a Slstaran ara ehed ee inn nepearaeneeast ylletins of Americ Begun in 1895 NUMBER 365 FEBRUARY 25, 2004 A Late Cambrian (Sunwaptan) Silicified Trilobite Fauna from Nevada by Jonathan M. Adrain and Stephen R. Westrop Paleontological Research Institution 1259 Trumansburg Road ithaca, New York, 14850 U.S.A. PALEONTOLOGICAL RESEARCH INSTITUTION Officers PRESIDENTE Ree etre On eT tn eee Tncacass na ear eye ene a CHRISTOPHER G. MAPLES RIRSTAVICE=PRESIDEN Te siraiicis aioe Gates Roca eee aa eke Davip H. TauBE SECOND WICE-BRESIDEN LE ie tieectsieiensiel teenie iene ie eee Patricia H. KELLEY SEGREGARY tyes Sine cet Ete cama ota it Mad Ri eeu NTs AE en ps Soe aw SHIRLEY K. EGAN IDREASURERM Rn tee et On Gea s ror teeter cs On air emer eure, A ees et i Tn Patricia A. JOHNSON IDIREGTOR! © Bn erat cuss cuales er cues LE oe re ee ee eee ale WarrREN D. ALLMON Trustees JoHN D. ALLEN Amy R. McCune Puitie BARTELS JOHN Poseta, JR. CARLTON E. BRETT PuiLip PROUJANSKY WILLIAM L. CREPET MeaGaNn D. SHay J. THomas Dutro, JR. Mary M. SHUFORD Howarp P. HartNETT ConsTANCE M. Soja PATRICIA HAUGEN JOHN C. STEINMETZ Rosert M. Horn, Jr. i PETER B. STIFEL Harry G. LEE ARTHUR WATERMAN Trustees Emeritus HArry A. LEFFINGWELL Rosert M. LINSLEY SAMUEL T. PEES Epwarp B. Picou, Jr. JAMES E. SORAUF RAYMOND VAN HoutTTE WILLIAM P. S. VENTRESS THOMAS E. WHITELEY BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA WAR REND ACANTSTERAONT wre ok teeees Svsireiss th acieu otis gis Mittaduatt/ tou ei ae a ie eel aaa ec teuses Pen isu Epitor A list of titles in both series, and available numbers and volumes are available online at www.priweb.org. Volumes 1—23 of Bulletins of American Paleontology are available from Periodicals Service Company, 11 Main St., Germantown, New York 12526 USA. Volume | of Palaeontographica Americana has been reprinted by Johnson Reprint Corporation, 111 Fifth Ave., New York, NY 10003 USA. Subscriptions to Bulletins of American Paleontology are available for US $165 per year (individual or institution) plus postage. Issues are available and priced in- dividually. Numbers of Palaeontographica Americana are priced individually. for additional information, contact: Paleontological Research Institution 1259 Trumansburg Road Ithaca, NY 14850 USA (607) 273-6623 FAX (607) 273-6620 www.priweb.org © This paper meets the requirements of ANSI/NISO 239.48-1992 (Permanence of Paper). NUMBER 365 . FEBRUARY 25, 2004 , HAR 25 LIBRARIES A Late Cambrian (Sunwaptan) Silicified Trilobite Fauna from Nevada by Jonathan M. Adrain and Stephen R. Westrop Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York, 14850 U.S.A. ISSN 0007-5779 ISBN 0-877 10-460-3 Library of Congress Control Number: 2003106844 Note: Beginning with issue number 356, Bulletins of American Paleontology is no longer designating volumes. The journal will continue to publish approximately 2—4 issues per year, each of which will continue to be individually numbered. Printed in the United States of America Allen Press, Inc. Lawrence, KS 66044 U.S.A. TABLE OF CONTENTS /XDSTENGY. -o- & 31a B Gibb onbnaIB0-0 6 poe ed. eine a eee ome eee aeque oe er ceeO Corry Syn ence B.A ac "OvcntT teeoOutt 6 a7. 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SATIS sochur ues dH enoe a GHOME Nemo OO RDU O DA GOnneUOboo opus doe Edge eure Ooge oD KoDOOnOGUS 29 IRETETETICESY Gite mmr Me Wee Ie esc wogs ieee ee icy ck ae ha aes 3) enlele ay vt Coe sueNe eNO A alual FTIaL oh ae sDIeIay wha ap ee brate sda cee ahiayinn aes eee en oeeane Iiawiriestalsaqeneies Sire 30 IRIGS 2 so ben & cla.e hdia ofp ducks ceced, Sia. cvu.4 cee Gene Geen a eee cune CaO Fiat Or oat oy A oN COL = CRN CLUne ranto me comic Distro bucec nok cid metenrcio 35 IGE. Stiogia B's hain .8-6 0 OLED os SE AO Sle ee Ais oe Ee REE OFS IRIN a ae IE aE eC Deere cite, 5 eae eran Lb anenin CP Sant daar A ion cin wer on nue Tire 55 AP ue Pe LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP A LATE CAMBRIAN (SUNWAPTAN) SILICIFIED TRILOBITE FAUNA FROM NEVADA JONATHAN M. ADRAIN Department of Geoscience 121 Trowbridge Hall University of lowa Iowa City, IA 52242 AND STEPHEN R. WESTROP Oklahoma Museum of Natural History and School of Geology and Geophysics University of Oklahoma Norman, OK 73072 ABSTRACT At Barton Canyon, Cherry Creek Range, east-central Nevada, a two-meter interval of the Bullwhacker Member of the Late Steptoean—Sunwaptan Windfall Formation has yielded abundant silicified sclerites. This Late Sunwaptan (Late Cambrian) assem- blage, assigned to the informal Bowmania lassieae Fauna, is correlative with the Prosaukia pyrene Subzone of Texas, and with the uppermost ///aenurus Fauna of southern Alberta. At least 15 species are present, and these represent 14 genera; Cherrycreekia and Glaberaspis are new. New species are Prosaukia oldyelleri, Sunwaptia plutoi, Euptychaspis dougali, Eurekia rintintini, Bowmania lassieae, Cherrycreekia benjii, and Glaberaspis scoobydooi. INTRODUCTION North American silicified trilobites of Ordovician age were studied intensively in the 1950s by Evitt (1951), Ross (1951), Hintze (1953), Whittington and Evitt (1954) and Whittington (1956, 1959), and the morphologic and ontogenetic information provided by this work contributed greatly to the understanding of the phylogenetic relationships of post-Cambrian groups. In contrast, silicified faunas are virtually un- known in the Cambrian (see Ludvigsen, 1982, for an important exception) and their phylogenetic potential is largely untapped. Here we document a new silicified fauna from a Late Cambrian (Sunwaptan) sequence in the Cherry Creek Range of east-central Nevada. Al- though it lacks early ontogenetic stages, the fauna pro- vides new insight into the morphology of a variety of genera. The fauna is also of significance because, al- though the trilobites of the underlying Steptoean stage have received considerable attention (Palmer, 1960, 1962, 1965), Sunwaptan trilobites of the Great Basin are essentially undocumented (see Taylor, 1976, for an exception). The fauna was collected from a two-meter interval of the upper Bullwhacker Member of the Windfall For- mation (Text-fig. 1) on the eastern side of the Cherry Creek Range, about 10 km north of the town of Cherry Creek (Text-fig. 2). The measured section runs along the crest of the ridge that forms the north side of Bar- ton Canyon. Here, the upper Bullwhacker is composed of thin-bedded, fossiliferous calcareous sandstones and sandy bioclastic grainstones, with minor oolitic pack- and grainstones, intrarudites and thrombolitic micro- bial buildups (Text-fig. 3). The fauna includes 15 spe- cies, six of which are new. ACKNOWLEDGMENTS This a joint study; the order of authorship is alpha- betical and does not indicate seniority. Support by the National Science Foundation through grant EAR- 9973065 is gratefully acknowledged. We thank Pete Palmer for suggesting the Cherry Creek section as a locality with potential for recovery of silicified faunas, and Brian Chatterton and Bruce Lieberman for helpful reviews. 6 BULLETIN 365 5 ~ v4 »y mS; Fe (es = EGO My AEG le Text-figure 1.—A. Steptoean—Early Ibexian lithostratigraphy, Cherry Creek Range. B. Correlation of lithostratigraphic units immediately to the south of the study area, along an east-west transect from the House Range (west-central Utah) to the Hot Creek Range (central Nevada) (modified from Osleger and Read, 1993). STRATIGRAPHIC AND ENVIRONMENTAL SETTING STRATIGRAPHY The Windfall Formation (Nolan er al., 1956) was established in the Eureka Mining District of east-cen- tral Nevada for a sequence of carbonates that overlies the shales and interbedded carbonates of the Dunder- berg Formation. The formation has also been recog- nized to the east and northeast of Eureka, in the Cherry Creek, northern Egan, and northern Schell Creek rang- es (Palmer, 1971). Nolan et al. (1956) divided the Windfall into, in ascending order, the Catlin and Bull- whacker members. In the type area, the Catlin is com- posed of two distinct lithologies. The lower nine me- ters consists of thick-bedded, light-colored lime mud- 2 WEST EAST Bl ; HOT CREEK WHITE PINE SNAKE HOUSE Notch Peak Formation RANGE RANGE RANGE RANGE L 1 L Bullwhacker SN Member Catlin Member Notch Peak ¢ Barton Canyon Mbr Dunderburg Whipple Cave-Windfall Formation Sneakover STEPTOEAN | SUNWAPTAN ~ IBEX Windfall Fm NEVADA UTAH Text-figure 2—Locality Map, showing the measured section along the ridge at the north side of Barton Canyon, Cherry Creek Range. stones, and this is succeeded by about 75 meters of thin-bedded cherty carbonates. Farther to the east, in the northern Schell Creek Range, Young (1960) as- signed the lower, light-colored carbonates to the Bar- ton Canyon Limestone (named for, and well exposed at, the sample locality of this study), effectively re- stricting the Catlin to the overlying cherty carbonates. Subsequent workers (e.g., Palmer, 1965, 1971) have followed Young in separating the Barton Canyon from the Catlin, and the three-fold division of the Windfall Formation is used herein (Text-fig. 1A). The upper boundary of the Windfall Formation in the Cherry Creek Range is placed immediately below the base of a massive, cliff-forming unit that is com- posed of stacked thrombolitic and stromatolitic micro- bial buildups (Text-fig. 4). In previous work, Adair (1961) placed this buildup-bearing interval at the base of the “‘Pogonip Group.” More recently, Osleger and Read (1993) interpreted a correlative interval of build- ups farther to the south, in the White Pine Range, as a tongue of the Notch Peak Formation. In its type area of the southern House Range, Utah, the Notch Peak includes a thick interval of buildups (Hintze, 1973; Hintze er al., 1988), and Osleger and Read’s interpre- tation is followed herein. The Barton Canyon Limestone yields faunas of the Elvinia Zone, with the base of the /rvingella major Zone (basal Sunwaptan) lying about 10 cm below the top of the member (Palmer, 1965; Adrain and Westrop, LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 7 Base of Notch Peak Fm. = 405 | 2 as 2 oO ‘= = 400 7 - 395 4 aS 390 + 385 4 380 + Poorly exposed, probably thrombolitic buildups ~ = ~ = es Sample interval ) yy WN MMi [ole [-)3 a4 @s Text-figure 3.—Stratigraphic column through the upper Bull- whacker Member, Barton Canyon, Cherry Creek Range, showing the interval that yielded the trilobite faunas described herein. Scale in meters above the base of the Catlin Member. The entire Bull- whacker is about 270 m in thickness at this locality. 1, sandy bio- clastic limestone and calcareous sandstone; 2, wave-rippled oolitic grainstone; 3, bioclastic rudstone; 4, intraclastic rudstone; 5, throm- bolitic microbial buildups. unpublished data). The basal few centimeters of the Catlin Member contains a fauna that includes Elvinia roemeri (Shumard, 1861), and this is followed by a 15-m interval with undescribed species of Loganellus Devine, 1863, Wujiajiania? Lu and Lin, 1980, and Drumaspis Resser, 1942 (Adrain and Westrop, unpub- lished data). The remainder of the Catlin is unfossil- iferous, but the faunas of the lower 100 m of the Bull- whacker resemble the deep subtidal assemblages of the Rabbitkettle Formation of northwestern Canada (Lud- vigsen, 1982; Westrop, 1995), and include /diomesus Raymond, 1924, Yukonaspis Kobayashi, 1936a, Ta- tonaspis Kobayashi, 1935, Parabriscoia Kobayashi, 1935, Hungaia Walcott, 1914, Elkanaspis Ludvigsen, 1982, Naustia Ludvigsen, 1982 and Eurekia Walcott, 1916. The upper Bullwhacker includes the fauna de- scribed herein, and its age and correlation are dis- cussed below. The base of the Notch Peak Formation is a 50-cm- thick bed of sandy, cross-bedded bioclastic rudstone that provides the foundation for the overlying micro- bial buildups. The trilobite fauna of this rudstone in- cludes Eurekia longifrons Westrop, 1986b and Men- iscocoryphe platycephala (Kobayashi, 1935), and demonstrates that the Windfall-Notch Peak boundary correlates with the Saukiella junia Subzone of Oklahoma (Stitt, 1971, 1977) and Texas (Longacre, 1970), and the Proricephalus wilcoxensis Fauna of Al- berta (Westrop, 1986b). The buildup-bearing interval assigned to the Notch Peak Formation is overlain by a thick interval of large- ly unstudied carbonates. The lower 25 m consist most- ly of bioturbated lime mudstones, with chert horizons appearing about 20 m above the top of the buildups. A silicified trilobite fauna was recovered 24.15 m above the top of the buildups, and this contains Apo- planias Lochman, 1964, Symphysurina Ulrich, in Wal- cott, 1924, and Parakoldinioidia stitti Fortey, 1983. It likely correlates with the upper Missisquoia or lower Symphysurina zones (e.g., Stitt, 1977), an interval which lies near the top of the Notch Peak Formation in west-central Utah (Hintze ef al., 1988). SEDIMENTARY FACIES The thin-bedded, cherty lime mudstones and shales of the Catlin Member record a sharp deepening fol- lowing the deposition of the shallow subtidal lime- stones of the Barton Canyon Limestone (see Brady and Rowell, 1976, for interpretation of the Barton Canyon Limestone and correlatives). The contact between the Catlin and the Bullwhacker Member is not exposed, and the latter is at least 270 m thick. The lower 100 m of the Bullwhacker consists of thin-bedded, unbi- oturbated lime mudstones with thin, dolomitic part- ings, and closely resembles the deep shelf facies of the Rabbitkettle Formation of northwest Canada (e.g., Ludvigsen, 1982, fig. 12D; Westrop, 1995, text-fig. 3). In higher parts of the Bullwhacker, lime mudstones are extensively bioturbated and dolomite-mottled, sug- 8 BULLETIN 365 Text-figure 4.—Skyline along ridge immediately to the north of the measured section, showing topographic expression of the Windfall and Notch Peak formations. D.R, Dunderburg Formation; B.C.L., Barton Canyon Limestone; C.M., Catlin Member; B.M., Bullwhacker Member; N.P.F, Notch Peak Formation; ?, unstudied cliff-forming carbonates of the ‘‘Pogonip Group.” Stratigraphic thickness from the base of the Catlin Member to the top of the lower, resistant cliff formed by the Notch Peak buildup complex is 514.5 m. gesting shallower, more oxygenated, subtidal condi- tions. In the upper 60 m of the Bullwhacker (Text-fig. 3), bioturbated lime mudstones are minor components of a succession that includes sandy bioclastic grain- stones and calcareous sandstones. Shallow subtidal conditions (above storm wave base) are indicated by intraclastic rudstones (“‘flat pebble conglomerates”) and pebbly intraclastic grainstones. Wave-rippled 0o- litic grainstones and thrombolitic buildups (1.5—3 m in thickness) also point to shallow-water conditions. The Bullwhacker Member may be interpreted as re- cording upward-shoaling from deep subtidal condi- tions, culminating with the appearance of the thick, microbial buildup complex recorded by the Notch Peak Formation. The appearance of quartz sand and silt in the upper Bullwhacker (about 20 m below the fauna described herein) may be of more than local sig- nificance. Osleger (1995; Osleger and Read, 1993) suggested that a sequence boundary could be recog- nized within the lower Saukia Zone throughout south- ern Laurentia (Virginia—Tennessee, Oklahoma, Texas and west-central Utah). The biostratigraphic control presented by Osleger (1995) is limited, but the calcar- eous sandstones and sandy carbonates of the Bull- whacker may be an expression of the same sea-level fall. AGE AND CORRELATION OF THE FAUNA The assemblage described here is assigned to an in- formal biostratigraphic unit, the Bowmania lassieae n. sp. Fauna. Several species occur in other parts of North America, including ///aenurus montanensis Kobayash1, 1935, Cherrycreekia benjii n. sp., and Corbinia im- plumis Winston and Nicholls, 1967. At Wilcox Peak, southern Alberta (Westrop, 1986b, text-fig. 31), 7 montanensis and C. benjii have been recorded from the upper part of the ///aenurus Zone, where they are separated by less than two meters of strata. Prorice- phalus scapane (Longacre, 1970) occurs with C. benjii in Alberta and is also present in the Prosaukia pyrene Subzone of the Wilberns Formation, central Texas (Longacre, 1970). Corbinia implumis is known from two figured spec- imens (Winston and Nicholls, 1967, pl. 9, fig. 3; Lon- gacre, 1970, pl. 3, fig. 13) from Texas that, according to boundaries defined by Longacre (1970, pp. 11—12), occur in the P. pyrene Subzone. In Alberta, this spe- cies extends from the upper ///aenurus Zone into the overlying Proricephalus wilcoxensis Fauna (Westrop, 1986b). Although the biostratigraphic data support a corre- lation with the upper ///aenurus Zone of Alberta and the Prosaukia pyrene Subzone of Texas, we have not assigned the fauna from the silty and sandy carbonates of the upper Bullwhacker to either of these units. Quantitative analyses of Late Sunwaptan_ trilobite abundance and distribution (Ludvigsen and Westrop, 1983a; Westrop, 1986b, 1995, 1996) have demonstrat- ed profound facies control, especially in carbonate en- vironments. Assemblages track lithofacies changes LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 9 (e.g., Westrop, 1996, fig. 9), and this provides un- equivocal evidence for the existence of environmen- tally controlled trilobite biofacies. Ludvigsen and Wes- trop (1983a; see also Ludvigsen et al., 1986) advocat- ed the use of separate zonations for different facies belts, and argued that correlation between zonations is best achieved through occurrences of relatively rare, widespread species. In contrast, Loch er al. (1993) ig- nored the complexities of facies control, and attempted to force all shallow-water facies into a single “‘stan- dard” zonation based on the succession in southern Oklahoma and central Texas. They noted that the first occurrences of Calvinella tenuisculpta Walcott, 1914, a species that occurs at the base of the Saukiella ser- otina Subzone in Oklahoma, and Stenopilus glaber (Westrop, 1986b) are within three meters of each other in Alberta. From this, they concluded that the Steno- pilus glaber Fauna of the latter region and the Sau- kiella serotina Subzone were equivalent. Calvinella tennuisculpta is, however, very rare in the Mistaya Formation (nine cranidia from three collections rep- resent less than two percent of the trilobites recovered from the S. glaber Fauna; Westrop, 1984), so that it is unlikely that the first appearance in Alberta is syn- chronous with that in Oklahoma. As noted by Loch er al. (1993), C. tenuisculpta and S. glaber make their first occurrence in the same collection in a section at Mt. Murchison. They fail to mention, however, that this is the on/y collection from the Mistaya Formation at that locality, and is separated from the closest un- derlying sample by more than 100 meters (Westrop, 1986b, fig. 24). As such, it says nothing about the order of appearance of these species. Similarly, their (Loch et al., 1993, p. 503) observation that the epon- ymous species is absent from the S. glaber Zone at Chaba Creek is irrelevant because the single collection from that locality contains only four trilobite sclerites (Westrop, 1984). Finally, the species that can be used to assign their section at Mt. Wilson to the Saukiella serotina Subzone are either poorly preserved, very rare (e.g., Euptychaspis kirki Kobayashi, 1935, is rep- resented by only one cranidium; Loch er al., 1993, Appendix 1) or misidentified (the larger of the two cranidia assigned to “Briscoia” Ilanoensis Winston and Nicholls, 1967, by Loch er al. [1993, fig. 6.18] shows a clearly defined anterior border and short preg- labellar field that is not present on material from the type area in Texas [Winston and Nicholls, 1967, pl. 10, figs. 1, 3, 5]). Thus, although an approximate cor- relation between Alberta and Oklahoma-Texas is pos- sible (Westrop, 1986b), use of a common zonal no- menclature implies a degree of accuracy that is not supported by the available data. SYSTEMATIC PALEONTOLOGY INTRODUCTION Our approach to systematic treatment of fossils is essentially that laid out by Smith (1994), and our spe- cles concept corresponds to what he defined as “phena.”” Morphological terminology follows Whit- tington (1997). Specimens are reposited in the Pale- ontology Repository, Department of Geoscience, Uni- versity of Iowa, with specimen numbers prefixed SUI. Trilobites were photographed using a Leitz Aristophot macrophotography system and Kodak Technical Pan film. Negatives were scanned using a Polaroid nega- tive scanner to produce digital images, which were ma- nipulated using Adobe Photoshop. Class TRILOBITA Walch, 1771 Family DIKELOCEPHALIDAE Miller, 1889 Discussion.—The problematic nature of many di- kelocephalid genera has been discussed often over the last 25 years (e.g. Taylor, in Taylor and Halley, 1974; Ludvigsen and Westrop, 1983b; Westrop, 1986b) but little progress has been made. The large number of taxa involved and their broad geographic distribution (e.g., Shergold, 1975; Ergaliev, 1980; Peng, 1984, 1992) make revision of the Dikelocephalidae a daunt- ing task that is well beyond the scope of this study. Genus DIKELOCEPHALUS Owen, 1852 Type species.—Dikelocephalus minnesotensis Owen, 1852, p. 574. Discussion.—The presence of a pair of posterolateral pygidial spines has generally been considered to be a diagnostic character of Dikelocephalus Owen (e.g., Westrop, 1986b; Hughes, 1994). Apart from the ab- sence of marginal spines, pygidia of several species cur- rently assigned to Briscoia Walcott, 1924, (e.g., Wes- trop, 1986b, pl. 2, figs. 3, 4) differ little from those of Dikelocephalus. It is also clear that the holaspid onto- genetic development of the frontal area in cranidia of Briscoia, in which the distinction between the pregla- bellar field and anterior border is lost (e.g., Westrop, 1986b, pl. 2, figs. 1, 5, 6, 7) is similar to that of Di- kelocephalus. Indeed, as noted by Westrop (1986b, p. 29), only the more anteriorly positioned palpebral lobe separates cranidia of Briscoia from Dikelocephalus, but similarly positioned palpebral lobes occur in a variety of other dikelocephalid genera (e.g., Longacre, 1970, pl. 4, figs. 16, 17; Taylor and Halley, 1974, pl. 2, fig. 2; Westrop, 1986b, pl. 4, figs. 1, 10). Thus, even if well- developed pygidial spines and posteriorly positioned palpebral lobes are apomorphies of Dikelocephalus, rec- ognition of the genus may create paraphyly in Briscoia. 10 BULLETIN 365 Resolution of this problem must await a comprehensive revision of the Dikelocephalidae. Dikelocephalus minnesotensis Owen, 1852 Plate 1, figures 1-26 Dikelocephalus minnesotensis Owen, 1852, p. 574, pl. 1, figs. 1, 2 (only), pl. la, figs. 3, 6; Hughes, 1994, p. 53, pls. 1-8, pl. 10, figs. 14, 15, pl. 11 (see for complete synonymy); Stitt and Straat- man, 1997, p. 86. Figured material.—One cranidium (SUI 99042), two pygidia (SUI 99048, 99051), one hypostome (SUI 99043), four librigenae (SUI 99045-99047) and two thoracic segments (SUI 99049, 99050). Discussion.—Hughes (1994), in his analysis of phe- notypic variation in the type area of the Upper Miss- sissippi1 Valley, advocated a broad species concept for Dikelocephalus minnesotensis. At least one other spe- cies, D. freebergensis Feniak (in Bell et al., 1952: Hughes, 1994, pl. 9, figs. 3-5, 17-19), may be repre- sented in the Sunwaptan of the Upper Mississippi Val- ley (see Hughes, 1994, p. 57). It differs from D. min- nesotensis in such pygidial features as longer, stouter marginal spines and a more transverse posterior py- gidial margin. Pygidia from the Bullwhacker Member (PI. 1, figs. 13, 18, 19, 22—26) possess a fourth axial ring that is poorly differentiated from the terminal piece and fall within the range of variation of specimens of D. min- nesotensis illustrated by Hughes. The pygidial dou- blure (Pl. 1, fig. 26) is very broad, and has a prominent medial notch beneath the terminal piece of the axis. In contrast, the doublure of Prosaukia oldyelleri n. sp. (Pl. 3, figs. 1, 18) is narrower, with an anterior margin that is bluntly rounded medially and extends forward only as far as the end of the postaxial ridge. A dou- blure similar to that of P. oldyelleri is also present in pygidia of Calvinella palpebra Ludvigsen (1982, fig. 58J) and, judging from the position of the faint para- doublural furrow or inflexion on the pleural field, in Hoytaspis speciosa (Walcott) (Ludvigsen and Westrop, 1983b, pl. 15, figs. 11-13), P. corrugata Rasetti (1959, pl. 54, figs. 6, 7) and P. stosei (Walcott) (Rasetti, 1959, pl. 54, fig. 17). The associated cranidium (PI.1, figs. 1-4) is much smaller than any that have been illustrated previously. It has a shorter frontal area than most larger holaspids from the Upper Mississippi Valley (e.g., Hughes, 1994, pl. 2, figs. 2, 3, pl. 3, figs. 1-6), although Hughes (1994, p. 26, figs. 18, 19) demonstrated sub- stantial variability in frontal area length. A distinct an- terior border and border furrow is present, and similar features can be seen on small cranidia from the Upper Mississippi Valley (e.g., Labandeira and Hughes, 1994, fig. 1.3). In this respect, it resembles small ho- laspids of Briscoia (Westrop, 1986b, pl. 2, fig. 5). Fi- nally, the palpebral lobe is relatively long (PI. 1, fig. 1; equal to slightly more than half of glabellar length), and this is consistent with Hughes’s (1994, p. 32, fig. 24) conclusion that palpebral lobe length is size-de- pendant. The hypostome of D. minnesotensis (Pl. 1, figs. 5, 6, 8) can be identified with confidence because of the association with complete cephala in Wisconsin (UI- rich and Resser, 1930, pl. 10, fig. 2). The expansion of the flat lateral border opposite the median furrow is particularly distinctive. Hypostomal borders of other dikelocephalids are variable. Some are similar to, but narrower than, those of Dikelocephalus (e.g., Sher- gold, 1991, pl. 4, figs. 7, 20), whereas others are con- vex and rim-like (e.g., Ulrich and Resser, 1933, pl. 36, fig. 14). A comparable range in morphologies, from flat and somewhat expanded (Westrop, 1986b, pl. 7, fig. 9, pl. 8, fig. 16) to convex rims (Westrop, 1986b, pl. 8, fig. 4), is seen among species of such outgroups as the ptychaspidid Ptychaspis Hall, 1863, so that character polarities are uncertain. Genus PROSAUKIA Ulrich and Resser, 1933 Type species.—Dikelocephalus misa Hall, 1863, p. 144. Discussion.—As discussed by Ludvigsen and Wes- trop (1983b, p. 30) and Westrop (1986b, p. 32), Pro- saukia and Saukiella Ulrich and Resser, 1933, are to some extent gradational and could prove to be syno- nyms. Part of the problem stems from the fact that Saukiella currently includes two groups of species that differ in the structure of the frontal area. The type species, Saukiella pepinensis (Owen, 1852) (Ulrich and Resser, 1933, pl. 32, figs. 1—4, pl. 33, fig. 22; Longacre, 1970, pl. 5, figs. 10, 11), and S. junia (Wal- cott, 1914) (Winston and Nicholls, 1967, pl. 9, figs. 8, 10, 12, 14; Longacre, 1970, pl. 5, figs. 13-17, 19, 20) both possess long frontal areas in which the pregla- bellar field is barely developed. In contrast, S. pyrene (Walcott, 1914) (Ulrich and Resser, 1933, pl. 34, pl. 35, fig. 1; Longacre, 1970, pl. 5, figs. 1-7), S. fallax (Walcott, 1914) (Longacre, 1970, pl. 5, figs. 1, 3) and S. serotina Longacre (1970, pl. 6, figs. 1-3) are char- acterized by short, subequally divided frontal areas that are comparable to those of Prosaukia (e.g., Lon- gacre, 1970, pl. 4, figs. 19-21; Ludvigsen and Wes- trop, 1983b, pl. 11, figs. 1-8; Westrop, 1986b, pl. 4, figs. 8-I1, 13). Indeed, of the criteria suggested by Longacre (1970, p. 49), only the confluent border fur- rows of the librigenae separate S. pyrene (e.g., Ulrich and Resser, 1933 pl. 34, pl. 35, figs. 2, 3, pl. 36, figs. 7-9) from Prosaukia hartti (Walcott, 1879) which has border furrows that do not meet (Ludvigsen and Wes- LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 11 trop, 1983b, pl. 11, fig. 10). Character polarities, how- ever, are uncertain because both states occur in out- groups to the Dikelocephalidae (for examples of iso- lated border furrows similar to those of P. hartti, see Ludvigsen, 1982, fig. 58N, fig. 59S, T; Westrop, 1986b, pl. 7, fig. 5, pl. 8, fig. 5; confluent border fur- rows occur in Keithiella depressa |Rasetti, 1944], see Ludvigsen and Westrop, 1983b, pl. 16, fig. 8). Among dikelocephalid genera, confluent border furrows are present in Calvinella (Walcott, 1914) (Ulrich and Res- ser, 1933, pl. 37, figs. 22, 24, 27, 28, 31, 32; Ludvig- sen, 1982, fig. S8F) and Tellerina Ulrich and Resser (1933, pl. 44, figs. 4, 19), whereas isolated furrows occur in Parabriscoia (Palmer, 1968, pl. 15, fig. 1). Thus, librigenal border morphology is ambiguous and does not demonstrate monophyly of Saukiella. As a tentative first step toward a revision of the dikelocephalid genera, we suggest restriction of Sau- kiella to S. pepinenis and S. junia, with frontal area proportions (long frontal area with very short pregla- bellar field) as a potential apomorphy. Saukiella py- rene, S. fallax, and S. serotina are transferred to Pro- saukia, and the diagnosis of Ludvigsen and Westrop (1983b) is followed herein. Prosaukia oldyelleri, new species Plate 2, figures 1-39, Plate 3, figures 1—41 Diagnosis.—A_ species of Prosaukia with small marginal spines on anteriormost pleura of pygidium. Anterior end of palpebral lobe reaches glabella, so that palpebral furrow joins axial furrow. Short, narrow frontal area has subtriangular anterior border. Description.—Strongly convex subrectangular gla- bella occupies about 85 percent of cranidial length and slightly less than 60 percent of cranidial width across palpebral lobes. Axial and preglabellar furrows are finely etched grooves, and are bowed outward at S1 and S2 lobes, especially in larger cranidia; glabella is weakly constricted opposite anterior ends of palpebral lobes. Longitudinal profile of glabella is gently convex between posterior margin and anterior tips of palpebral lobes, but curves steeply downward anteriorly. Occip- ital furrow is narrow (sag.), roughly transverse groove. S1 furrows are curved gently backward and connected across glabella, although become somewhat shallower medially. S2 furrows also curved backward although are well defined only near axial furrows; may be con- nected across glabella in some individuals. Frontal area is short and narrow, with maximum width equal to about 70 percent of cranidial width across palpebral lobes; unequally divided into short preglabellar field and longer, convex, subtriangular anterior border by shallow, forwardly curved border furrow. Long, flat, strongly curved palpebral lobes are centered slightly in front of anterior tips of SI furrows and extend from occipital furrow to mid-point of frontal glabellar lobe: separated posteriorly from glabella by narrow strips of fixigenae but abut glabella anteriorly. Palpebral furrow is finely etched groove that merges with axial furrow anteriorly; palpebral lobe may be subequally divided by barely perceptible furrow that parallels palpebral furrow. Posterior branches of facial sutures diverge sharply backward. Anterior branches moderately di- vergent near palpebral lobe, curving gradually inward to become nearly parallel at anterior border furrow be- fore converging abruptly inward along anterior crani- dial margin. Posterior fixigenae narrow, strap-like; in anterior view, flexed downward at about 30 degrees. Posterior border furrow very shallow, finely etched groove. Glabella, interocular fixigenae and anterior border have sculpture of terrace ridges: palpebral lobes and preglabellar field are smooth. Occipital ring may carry minute occipital spine. Librigenae separated by median suture. Long, slen- der genal spine curves gently inward; equal to about 275 percent of length of librigenal field. Moderately inflated librigenal field separated from convex poste- rior and lateral border by shallow, confluent border furrows. Eye socle consists of two wire-like bands sep- arated by finely etched longitudinal furrow. Inner edge of doublure lies beneath lateral border furrow but di- verges posteriorly from posterior border furrow, so that doublure narrows laterally away from genal angle. Genal spine, borders, doublure and librigenal field car- ry sculpture of terrace ridges. Pygidium subelliptical in outline, with length about 66 percent of maximum width; pair of minute marginal spines located slightly anterior of posterior tip of axis. Convex axis accounts for about half of pygidial height in lateral view, and about 40 percent of pygidial width at anteriormost axial ring; tapers backward and occu- pies slightly more than 75 percent of pygidial length; post-axial ridge terminates close to pygidial border. Axial furrows are shallow grooves. Four subequal ax- ial rings and rounded terminal piece separated by sub- transverse axial ring furrows; semielliptical articulat- ing half-ring equal to about 75 percent of length of anteriormost axial ring. Pleural field nearly flat at axial furrow but flexed downward, becoming nearly flat at pygidial margin. Inner edge of doublure underlies point of downward flexure of pleural field and does not reach posterior end of axis. Pleural and interpleural furrows well defined and curve outward and backward to terminate just short of pygidial margin; degree of curvature decreases in successive furrows so that pos- teriormost are nearly straight. Apart from anteriormost, convex anterior and posterior pleural bands subequal in length. Pleural field and doublure carry fine terrace 12 BULLETIN 365 ridges that roughly parallel pygidial margin; axis also with terrace ridges. Holotype.—A cranidium (SUI 99054; PI. 2, figs. 3, 4,7, 11) from the Bullwhacker Member, Windfall For- mation, Barton Canyon, Cherry Creek Range, Nevada. Figured material.—Eleven cranidia (SUI 99052— 99062), four librigenae (SUI 99063, 99064, 99080, 99081), and 14 pygidia (SUI 99065—99079). Etymology.—Named for Old Yeller. Discussion.— Prosaukia oldyelleri n. sp. is unusual in possessing palpebral lobes whose anterior tips abut the glabella. The typical dikelocephalid condition has the anterior end of the palpebral lobe separated from the glabella by a strip of fixigena of variable width (e.g., Prosaukia |Rasetti, 1959, pl. 54, figs. 4, 5, 9, 16, 22; Longacre, 1970, pl. 4, figs. 19-21; Taylor and Hal- ley, 1974, pl. 2, figs. 15-17; Ludvigsen and Westrop, 1983b, pl. 10, figs. 1, 3; Westrop, 1986b, pl. 4, figs. 8-11]; Calvinella Walcott, 1914 [Nelson, 1951, pl. 110, fig. 21; Longacre, 1970, pl. 4, figs. 16, 17; Taylor and Halley, 1974, pl. 2, figs. 2, 3]; Saukia Walcott, 1914 [Westrop, 1986b, pl. 3, figs. 8, 9, 11]; Hoytaspis Ludvigsen and Westrop [1983b, pl. 14, fig. 1, 8]; Sau- kiella Ulrich and Resser, 1933 [Longacre, 1970, pl. 5, figs. 10, 12, 17]; Stigmaspis Nelson, 1951 [Westrop, 1986b, pl. 4, figs. 1, 3-5]; Tellerina Ulrich and Resser, 1933 [Nelson, 1951, pl. 112, figs. 5, 12]; Briscoia Wal- cott, 1924 [Walcott, 1925, pl. 20, fig. 1; Westrop, 1986b, pl. 2, figs. 1, 5-7, 10]: Parabriscoia Kobay- ashi, 1935 [Palmer, 1968, pl. 15, figs. 2, 5; Westrop, 1995, pl. 1, figs. 28]; Elkia Walcott, 1924 [Walcott, 1925, pl. 18, figs. 1, 2]; Dikelocephalus Owen, 1952 [Hughes, 1994, pl. 2, figs. 1-3, 6, 7]; Lophosaukia Shergold, 1972 [Shergold, 1975, pl. 18, fig. 1; Peng, 1992, fig. 24B]; Mictosaukia Shergold, 1975 [Robison and Pantoja-Alor, 1968, pl. 104, figs. 13, 18; Shergold, 1975, pl. 24, fig. 10; Peng, 1992, fig. 24H]; Anders- sonella Kobayashi, 1936b [Shergold, 1975, pl. 20, fig. 4]; Galerosaukia Shergold [1975, pl. 22, fig. 9]; Caz- naia Shergold [1975, pl. 25, fig. 1]; Platysaukia Ko- bayashi, 1960 [Shergold, 1991, pl. 3, fig. 8]; Eosaukia Lu, 1954 [Shergold, 1991, pl. 5, fig. 21]). Although the anterior branches of the facial sutures are sharply divergent, the position of the palpebral lobes of P. old- yelleri results in a relatively narrow frontal area that also differs from typical dikelocephalids. Only Osceo- lia osceola (Hall, 1863) (Nelson, 1951, pl. 110, fig. 9) and at least some specimens of Prosaukia pyrene (Walcott, 1914) (e.g., Ulrich and Resser, 1933, pl. 34, pl. 35, fig. 1; Nelson, 1951, pl. 110, fig. 4) have pal- pebral lobes in a position that is similar to P. oldyel- leri. Osceolia osceola, however, is differentiated read- ily by a much longer frontal area on the cranidium and a pygidium (Nelson, 1951, pl. 110, fig. 10) that lacks interpleural furrows and has very long, stout marginal spines on the anteriormost pleura. Prosaukia pyrene has less strongly divergent anterior branches of the fa- cial sutures, and an arcuate anterior border that results in an evenly rounded anterior cranidial margin. The minute marginal spines on the anteriormost pleura and associated embayment of the lateral margin separate pygidia of P. oldyelleri trom those of all pre- viously described members of Prosaukia, although similarly sized spines could perhaps be overlooked or destroyed in preparation of “‘crackout” pygidia of oth- er species. The only other spinose species is P. spinula Taylor (in Taylor and Halley, 1974, pl. 2, figs. 18, 20), but in that species, a single median spine is present. Apart from the absence of marginal spines, pygidia of P. pyrene (Longacre, 1970, pl. 5, fig. 8) are very similar to those of P. oldyelleri. The type species, P. misa (Hall, 1863) (Westrop, 1986b, pl. 4, fig. 14), pos- sesses pygidia that differ from those of P. oldyelleri and P. pyrene in having an axis composed of three, rather than four, axial rings plus terminal piece, where- as P. hartti (Walcott, 1879) (Ludvigsen and Westrop, 1983b, pl. 11, fig. 12) has five rings and a terminal piece. The thoracic segment illustrated on Plate 17 (figs. 41, 46. 50) probably belongs to a dikelocephalid tri- lobite. We hesitate to assign it to P. oldyelleri because the coarse granules on the pleural bands and along the posterior margin of the axial ring are not present on any of the sclerites that can be confidently attributed to this species. Family PTYCHASPIDIDAE Raymond, 1924 Subfamily PTYCHASPIDINAE Raymond, 1924 Discussion.—The genera of the Ptychaspidinae are in need of revision. Among North American represen- tatives of the subfamily, monophyly of /diomesus Ray- mond, 1924, is supported by substantial eye reduction or loss. Keithia Raymond, 1924, is defined by an ex- panded, bulb-shaped glabella that partly or completely overhangs the anterior border. Proricephalus Westrop, 1986a, (and its probable synonym Plectrella Ludvig- sen and Westrop, in Ludvigsen et al., 1989) can be diagnosed on the structure of the frontal area. The sta- tus of Prychaspis Hall, 1863, and Keithiella Rasetti, 1944, is less certain. These genera have been separated by the expression of the anterior border and border furrow (e.g., Longacre, 1970; Westrop, 1986b; Lud- vigsen et al., 1989). Keithiella possesses a convex an- terior border and firmly impressed anterior border fur- row, Whereas Prychaspis is characterized by an undif- ferentiated frontal area. By comparison with outgroups in the Dikelocephaloidea (e.g., Westrop, 1986b, pl. 5, LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 13 figs. 1, 2, 6), the condition in Keithiella is most likely plesiomorphic. The frontal area morphology of Pry- chaspis is, however, shared with /diomesus. Thus, it is possible that both Prychaspis and Keithiella are para- phyletic. Any phylogenetic analysis will need to con- sider Australian and Chinese representatives of the subfamily, including Asioptychaspis Kobayashi, 1933 (regarded as a synomym of Ptychaspis by Shergold, 1991), Changia Sun, 1924, and Quadraticephalus Sun, 1924. Genus IDIOMESUS Raymond, 1924 Type species.—Idiomesus tantillus Raymond, 1924, paso. Idiomesus levisensis (Rasetti, 1944) Plate 4, figures 1-20, 22, 23 Stigmametopus levisensis Rasetti, 1944, p. 257, pl. 37, figs. 8, 9. Idiomesus levisensis (Rasetti). Taylor, 1976, p. 686, pl. 3, figs. 12, 13 (see for complete synonymy); Ludvigsen and Westrop, 1986, p. 305, pl. 20, figs. 5, 6D (see for synonymy); Ludvigsen, Wes- trop and Kindle, 1989, p. 32, pl. 20, figs. 8-13; Westrop, 1995, p. 24, pl. 7, fig. 24. Figured material.—Six cranidia (SUI 99082— 99088) and three librigenae (SUI 92089-92091). Discussion.—The spindle-shaped glabella with S2 and S3 lateral glabellar furrows is characteristic of /di- omesus levisensis (Rasetti) (see Taylor, 1976, p. 686; Ludvigsen and Westrop, 1986). The librigena, illus- trated here for the first time (PI. 4, figs. 19, 20, 22, 23), carries a long, gently curved genal spine that con- trasts with the minute spine of /. tantillus Raymond (Ludvigsen, 1982, fig. 54R) Subfamily MACRONODINAE Westrop, 1986a Genus SUNWAPTIA Westrop, 1986a Type species.—Sunwaptia carinata Westrop, 1986a, p. 218. Discussion.—Pygidial morphology offers potential synapomorphies for the Macronodinae (Adrain and Westrop, 2001, fig. 8), so that the discovery of the pygidium of Sunwaptia (Pl. 5, figs. 21-32) is of phy- logenetic significance. As in Macronoda (Lochman, 1964, pl. 14, figs. 14, 18, 19, 21, 22; Westrop, 1986b, Pl hisss 6, 7: Locher al) 1993) fis: 6:24), it 1s subtriangular in outline, with a long axis and narrow pleural fields. Moreover, Sunwaptia and Macronoda possess pits in the border furrow, and this character is an unequivocal synapomorphy. Sunwaptia differs in that the pits are overlain by swollen protuberances that extend inward from the border. The two genera also differ in the segmentation of the pygidial axis. The axis of Sunwaptia plutoi n. sp. has three or four axial rings, with a long terminal piece that occupies at least one-third of axial length. In contrast, pygidia of Ma- cronoda have multisegmented axes, with up to at least 14 poorly defined axial rings (Loch er al., 1993, p. Si/2): Sunwaptia plutoi, new species Plate 4, figures 21, 24—26, Plate 5, figures 1—32 Diagnosis.—A species of Sunwaptia in which fixi- genal ridge is poorly defined or absent. Palpebral lobe relatively small. Anterior cranidial arch weak. Description.—Cranidium subsemielliptical in out- line, with length equal to 60 percent maximum width; posterior margin curved backward, so that posterior tips of fixigenae extend back well beyond occipital ring. Glabella strongly convex and accounts for about 75 percent of cranidial height in anterior view; bulb shaped in outline, and occupies about 90 percent of cranidial length and nearly 50 percent of cranidial width across palpebral lobes. Longitudinal profile hor- izontal between posterior margin and S1 furrow, be- coming arched strongly upward at frontal lobe before curving almost vertically downward at anterior. Axial and preglabellar furrows moderately impressed grooves. Occipital furrow deeply incised, transverse; occipital ring equal to about 15 percent of glabellar length and with posterior margin bowed gently back- ward. S1 firmly impressed transverse groove; LI trans- verse band, roughly equal in length to occipital ring. Frontal lobe suboval in outline and strongly inflated, with maximum height in lateral view equal to 150— 175 percent of height of L1; maximum width opposite palpebral ridge and equal to 130—145 percent of width of L1. Anterior border furrows shallow, diverging for- ward from anterior corners of glabella to anterior cor- ners of cranidium; anterior border nearly flat medially but arched strongly downward in anterior view in all but smallest cranidium (PI. 5, fig. 9). Palpebral lobe ill-defined inflated area at abaxial end of conspicuous, gently curved, wall-like palpebral ridge; located in front of mid-length of anterior glabellar lobe. Anterior branches of facial suture run forward and inward from palpebral lobe; posterior branches diverge gradually backward before curving slightly inward near posterior corner of cranidium. Posterior fixigena broad, maxi- mum width equal to about 300 percent of interocular fixigena; slopes steeply upward from axial furrow, cre- ating broad, arcuate, depressed area from palpebral ridge to S1 furrow; reaches maximum convexity be- hind palpebral lobe before flexing downward to lateral cranidial margin. Some individuals show low fixigenal ridge extending for short distance posterolaterally from palpebral lobe (PI. 4, figs. 25, 26). Posterior border furrow deeply incised, slot-like, and curves gently backward from axial furrow; posterior border convex, 14 BULLETIN 365 curving gently backward and expanding distally, so that length is less than length of occipital ring at axial furrow but is subequal at posterior corner. Well-pre- served cranidia (PI. 5, figs. 1, 4, 5) with coarse tuber- cles along crest of glabella, becoming finer along the sides; larger tubercles perforated by large pore. Near axial furrow, glabella mostly smooth, as is adjacent portion of posterior fixigena. Outer parts of posterior fixigena with closely spaced fine tubercles and scat- tered coarser tubercles. Librigena with short, broad-based, subtriangular ge- nal spine. Librigenal field broad and moderately in- flated. Lateral border furrow moderately impressed, running parallel to border posteriorly, then diverges from border, curving backward and inward as shallow paradoublural furrow; posteriorly, border furrow ill de- fined, marked by change in slope. Lateral border con- vex, best defined anteriorly, and merges with rim-like posterior border at tip of genal spine. Outer edge of weakly convex doublure follows anterior border and paradoublural furrows. Sculpture of very fine terrace ridges on doublure; remainder of librigena smooth. Pygidium subtriangular in outline, with length slight less than 70 percent of maximum width. Axis long, extending back to border and narrow, accounting for about 25 percent of maximum pygidial width; parallel sided to gently tapered anteriorly but with terminal piece expanded posteriorly, and strongly convex, standing well above pleural fields. Four axial rings and long terminal piece separated by firmly impressed, for- wardly curved ring furrows; successive rings decrease slightly in length, so that posteriormost about 75 per- cent length of anteriormost; terminal piece accounts for about 40 percent of axis length. Articulating half- ring short, equal to 25 percent of length of adjacent axial ring, with very gently curved anterior margin: articulating furrow also gently curved and firmly im- pressed. Pleural field triangular in outline and flexed downward from axis; crossed by three pairs of firmly impressed, oblique pleural furrows; interpleural fur- rows barely perceptible on broad pleural bands. Border narrow, convex rim; border furrow with four pairs pits that are overlain by swollen protuberances that extend inward from the border. Doublure narrow, convex, so that border is subcircular in cross-section. Dorsal sur- face of pygidium smooth except for coarse terrace ridges on border. Holotype.—A cranidium (SUI 99092; PI. 4, figs. 21, 24—26) from the Bullwhacker Member, Windfall For- mation, Barton Canyon, Cherry Creek Range. Figured material.—Six cranidia (SUI 99092— 99097), three librigenae (SUI 99098—99100), and four pygidia (SUI 99101-99104). Etymology.—Named for Pluto Pup. Discussion.—Sunwaptia plutoi n. sp. is very similar to the type species, Sunwaptia carinata Westrop (1986a, figs. 4A-E; 1986b, pl. 11, figs. 9-13), from the Mistaya Formation of Alberta, but clearly differs in that the fixigenal ridge extending from the palpebral lobe to the posterior border furrow is poorly defined, extending for only a short distance from palpebral lobe (e.g., Pl. 4, figs. 25, 26), or absent (e.g., Pl. 5, figs. 10, 14, 17). Other differences in S. plutoi include a some- what longer L1 glabellar lobe, a less pronounced an- terior arch, and a smaller palpebral lobe. The smallest cranidium (PI. 5, figs. 8, 9) has a transverse, rather than arched, anterior margin, and appears to have a faint anterior border furrow and rim-like border. Subfamily EUPTYCHASPIDINAE Hupé, 1953 Discussion.—Ingroup relationships of both the Eup- tychaspidinae and Macronodinae have been discussed recently by Adrain and Westrop (2001). As currently conceived, the Euptychaspidinae is confined to the Up- per Sunwaptan (sensu Ludvigsen and Westrop, 1985) of North America, although Briggs ef al. (1988) and Edgecombe (1992) suggested that Curiaspis Sdzuy, 1955, from the Leimitz Shale of Germany, might be an Ordovician ptychaspidid. Among the Ptychaspidi- dae, glabellar structure of Curiaspis (Sdzuy, 1955, p. 7, figs. 11-16) is most similar to Euptychaspis, sharing transglabellar S1 and S2 furrows and a rounded ante- rior lobe. It has comparable palpebral lobes, but lacks the ridge-like extensions of the border on the occipital ring, which carries a conventional spine. Unlike Eup- tychaspis (and any other dikelocephaloidean), Curias- pis is proparian, with a short, slender genal spine. The relationship between Curiaspis and the euptychaspi- dines is uncertain, although discovery of the pygidium may clarifiy the affinities of this genus. Calvipelta Westrop, 1986b, a small, effaced, blind trilobite from the Late Sunwaptan of Alberta, may prove to be a euptychaspidine. The poorly defined, parallel-sided glabella shares features with Euptychas- pis (Pl. 6, figs. 1, 2, 4, 8; see also Ludvigsen, 1982, fig. SSK—M, Q, V, W). Although not connected across the glabella, distinct Sl and S2 lateral furrows are present, and the frontal lobe may be slightly expanded (Westrop, 1986b, pl. 41, figs. 33-35). In addition, the posterior border is curved backward to merge with the occipital ring. This resembles the structure of the oc- cipital ring in Euptychaspis, in which the posterior border is extended backward as ridge (PI. 6, figs. 1, 2, 4, 8; see also Ludvigsen, 1982, fig. S3K—M). The ex- ternal surface of the pygidial exoskeleton appears to have been entirely effaced (Westrop, 1986b, pl. 41, fig. 36), but internal molds show that the axial, axial ring and pleural furrows were expressed on the ventral sur- LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP | face. The axis is similar in width to that of Eupty- chaspis (e.g., Pl. 6, fig. 39), but the pleural field is broader. The pleural field is, however, more closely comparable to that of Larifugula leonensis (Winston and Nicholls, 1967) (Ludvigsen, 1982, fig. 67R), which was assigned to the Euptychaspidinae by Adrain and Westrop (2001). Genus EUPTYCHASPIS Ulrich in Bridge, 1931 Type species.—Euptychaspis typicalis Ulrich in Bridge, 1931. p. 218. Discussion.—Euptychaspis has to this point con- sisted of three named species: E. typicalis, the type species, E. kirki Kobayashi, 1935, and E. jugalis Win- ston and Nicholls, 1967. Euptychaspis frontalis Lon- gacre, 1970, has been assigned to Kathleenella Lud- vigsen, 1982. The holotype of Euptychaspis tremato- cus Hu, 1973, appears to be a shumardiid, and the pygidium associated by Hu (1973, pl. 2, fig. 14) ap- pears to represent a missisquoiid. Euptychaspis typicalis is known in its type occur- rence in the Eminence Dolomite of Missouri from a tiny, retouched photograph (Ulrich in Bridge, 1931, pl. 19, fig. 7) of a dolomitic internal mold of cranidium lacking its occipital spine and posterior fixigenae, along with two stylized line drawings (Ulrich in Bridge, 1931, pl. 19, figs. 5, 6). The types have never been revised, and no other material from the Eminence Dolomite has ever been figured. Documentation of the types of Euptychaspis kirki is equally poor. The two incomplete, poorly preserved cranidia (Kobayashi, 1935, pl. 10, figs 4, 5) from the Windfall Formation in the Eureka mining district, Nevada, have never been revised, and no other material from this unit has ever been illustrated. Euptychaspis jugalis is known from a tiny stereopair photograph of a single incomplete cran- idium (Winston and Nicholls, 1967, pl. 9, fig. 13) from the San Saba Member of the Wilberns Formation, Tex- as. Longacre (1970, pl. 3, fig. 18) figured another ster- eopair of a large cranidium from the type area but it is so poorly preserved that it is far from clear that it is actually conspecific with Winston and Nicholls’ ho- lotype. Taken together, the type material of the species as- signed to Euptychaspis provide a woefully inadequate basis for comparison. Nevertheless, the names E. typ- icalis and E. kirki have been used for many occur- rences of Euptychaspis, in widely separated regions of Laurentia, and both species have come to be regarded as biostratigraphically important. Material has been as- signed to Euptychaspis typicalis from Texas (Dake and Bridge, 1932; Winston and Nicholls, 1967; Longacre, 1970), Maryland (Rasetti, 1959), Oklahoma (Stitt, 1971), New York State (Taylor and Halley, 1974), the Nn Mackenzie Mountains (Ludvigsen, 1982), and the southern Canadian Rocky Mountains (Westrop, 1986b). Similarly, Euptychaspis kirki has been report- ed from Texas (Winston and Nicholls, 1967; Longacre, 1970), Oklahoma (Stitt, 1971), and the Mackenzie Mountains (Westrop, 1995). The species have also been used to support the trilobite biostratigraphy of potential Cambrian-Ordovician boundary stratotype sections in western Utah (e.g., Miller ef al., 1982; see also Hintze et al., 1988; Loch er al., 1999), though no specimens have ever been figured. Close examination of the range of intra-sample var- iation in these reports suggests that pervasive morpho- logical differences exist between some samples from different regions, and that in the case of both E. typi- calis and E. kirki, a plexus of related species has been confused as a single species, largely on the basis of inadequate documentation. We will deal with the spe- cies regarded as Euptychaspis kirki in a forthcoming work. Here we document an unequivocal new species that would have been assigned under previous practice to the broad wastebasket of E. typicalis. The status of other occurrences assigned to E. typicalis is discussed below. Euptychaspis dougali, new species Plate 6, figures 1—44 Diagnosis.—S1 only weakly impressed medially in most specimens; S2 restricted to notches adjacent to the axial furrows, not impressed medially and not forming a single transverse furrow; L1 and L2 lacking sharp, scarp-like anterior and posterior margins; eye ridge not discernible dorsally or ventrally; interocular fixigenae broad; genal spine very long; pygidium with three axial rings. Description.—Cranidium subpentagonal in outline, with length (excluding occipital spine) equal to about 60 percent of width at posterior; strongly convex with height opposite palpebral lobes equal to about half of cranidial length (excluding occipital ring). Glabella parallel sided, well rounded anteriorly, strongly con- vex and raised well above adjacent fixigenae at L1 lobe; occupies about 80 percent of cranidial length (ex- cluding occipital ring) and 40 percent of cranidial width between the palpebral lobes. In front of occipital ring, longitudinal profile of glabella curves steadily downward so that anterior part of anterior lobe weakly raised above surrounding fixigenae. Axial and preg- labellar furrows narrow but well-defined grooves. Composite occipital ring includes slender, steeply in- clined occipital spine equal to about 60 percent of pre- occipital glabellar length; ring and spine enclosed by raised rims that are extensions of posterior border and that join beneath posterior tip of spine. Occipital fur- 16 BULLETIN 365 row finely etched groove, transverse or bowed gently forward. S1 furrow transglabellar (Pl. 6, fig. 4, 22), deepest at axial furrow but shallow medially. S2 lateral furrow well incised, narrow (tr.), extending inward for about 15 percent of glabellar width, and not connected across glabella. L1 lobe convex, subtransverse band and slightly wider (tr.) than occipital ring. L2 lobe sub- equal in length and width to L1. Frontal lobe weakly inflated, well rounded anteriorly, and accounts for about 50 percent of preoccipital glabellar length. Fron- tal area slopes forward to terminate at minute trian- gular border that is littke more than expanded sculp- tural ridge. Palpebral area of fixigenae nearly flat. Pal- pebral lobe semielliptical, upturned flap, length about one-third of preoccipital glabellar length; palpebral furrow finely etched groove. Anterior branches of fa- cial suture initially gently convergent before swinging sharply inward along anterior cranidial margin; pos- terior branches diverge gradually backward. Convex posterior border slightly shorter (exsag.) than L1 lobe and separated from fixigena by firmly impressed bor- der furrow. Doublure beneath border short near axial furrow but increases in length (exsag.) distally. Frontal area with coarse, irregular sculptural ridges that are roughly parallel to cranidial margin. With exception of smooth cranidial furrows, posterior border and ridge along occipital spine, remainder of cranidium has sculpture of irregular, coarse anastomosing ridges. Sculpture not expressed on ventral surface (PI. 6, fig. 3). Librigenae with long genal spine narrowing back- ward and gently curved distally; length somewhat more than twice length of genal field. Genal field con- vex, accounting for more than half of height of libri- gena in lateral view, with distinct eye socle overlain by visual surface of eye. Posteriorly, librigenal field merges with broad, anterior end of carinate ridge ex- tending along entire length of genal spine. Lateral bor- der furrow is broad shallow groove; lateral border con- vex and steeply downsloping. Posterior border furrow firmly impressed and does not join lateral border: ex- tends along inner edge of genal spine as narrow, weak- ly concave band that lacks sculpture. Narrow, tubular doublure beneath borders and raised above adjacent doublure of genal spine. Genal field, borders and spine with coarse, weakly anastomosing sculptural ridges that run roughly parallel to margin; border furrows and doublure smooth. Pygidium elliptical in outline with length about 60 percent of maximum width; strongly convex, with height in posterior view equal to about half of pygidial width. Posterior margin with narrow, upward medial embayment. Axis and very narrow pleural field en- closed by narrow, rim-like ridges that extend backward and inward from anterior pygidial margin to join be- hind axis. Convex axis tapers gently backward and oc- cupies about 65 percent of pygidial length; width at anterior axial ring equal to slightly less than 40 percent of maximum pygidial width. Three axial rings sube- qual in length and separated by finely etched, trans- verse ring furrows. Forwardly curved articulating half ring bounded posteriorly by transverse, finely etched articulating furrow. Pleural field with firmly impressed pleural furrow at anterior; remaining pleural and in- terpleural furrows shallow to barely perceptible. Broad posterior border slopes steeply downward from ridges bounding axis and pleural field. Border carries sculp- ture of anastomosing terrace ridges whereas axis has coarser anastomising ridges; pleural fields and pygidial furrows smooth. Holotype.—A cranidium (SUI 99105; Pl. 6, figs. 1, 5, 11, 12, 22) from the Bullwhacker Member, Windfall Formation, Barton Canyon, Cherry Creek Range. Figured material.—Seven cranidia (SUI 99105— 99110, 99115, 99119), seven librigena (SUI 99111— 99114, 99116-99118, 99122, 99123), and two pygidia (SUI 99120, 99121). Etymology.—After Dougal, of the Magic Round- about. Discussion.—The most striking feature of Eupty- chaspis dougali is the presence of S2 furrows that are not connected across the glabella. A transglabellar S2 furrow is clearly present in Ulrich’s photographed type specimen of Euptychaspis typicalis (Ulrich in Bridge, 1931, pl. 19, fig. 7). Moreover, in all reasonably well- known cranidia that have been assigned to E. typicalis (Rasetti, 1959, pl. 52, figs. 11-13; Winston and Nich- olls, 1967, pl. 9, fig. 17; Longacre, 1970, pl. 4, fig. 9: Stitt, 1971, pl. 6, fig. 19; Taylor in Taylor and Halley, 1974, pl. 2, figs 4-6; Ludvigsen, 1982, fig. 58K, Q, V; Westrop, 1986b, pl. 10, figs 22, 23), both SI and S2 are transglabellar and expressed in the central body of the glabella as distinct, unsculptured, transverse trenches. Both L1 and L2 are convex, transverse bands that extend across the glabella and whose anterior and posterior margins are sharply defined at a vertical, scarp-like break in slope. Opposite the notch-like S2 of E. dougali, the glabellar sculpture of coarse, anas- tomosing ridges extends without interruption across the central area of the glabella. SI is generally more weakly developed in £. dougali than in any cranidia assigned to E. typicalis. Although this furrow is clearly transverse (confirmed by the presence of a furrow in ventral view, Pl. 6, figs. 3, 22), it is much deeper and notch-like near the axial furrow and very shallow to nearly indistinct (e.g., Pl. 6, fig. 2) medially. In several specimens, the glabellar sculpture runs medially across S1 essentially without interruption. This glabellar mor- LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP E7/ phology is unique within the genus, and it alone serves to differentiate E. dougali from all other occurrences of Euptychaspis. The species differs in detail in other ways from various taxa assigned to E. typicalis, and to clarify these contrasts it is necessary to evaluate each of these occurrences: The type material of E. typicalis is totally inade- quate and cannot be meaningfully compared with other taxa. Euptychaspis typicalis should be restricted to its type specimens, until such time as it is revised on the basis of new and better material. Occurrences in Texas (Winston and Nicholls, 1967; Longacre, 1970) and Oklahoma (Stitt, 1971) are so poorly documented that they, too, cannot be meaning- fully compared with other taxa. Until such time as they are adequately described, with more cranidia, knowl- edge of librigena and pygidia, etc., they should be re- garded as Euptychaspis cf. typicalis. For the same rea- sons, two cranidia from Maryland (Rasetti, 1959) should also be placed in open nomenclature. We regard occurrences of Euptychaspis from the Whitehall Formation of New York (Taylor in Taylor and Halley, 1974) and the Rabbitkettle Formation of northwest Canada (Ludvigsen, 1982) as each repre- senting a distinct species, but we are reluctant to for- mally name them in the present state of knowledge. The Whitehall material is known from three cranidia, a librigena, and a pygidium (Taylor and Halley, pl. 2, figs. 4-11). It differs from what little is known of E. typicalis most prominently in the fact that its L1 is substantially wider than its L2 (this also distinguishes it from all other material assigned to E. typicalis). Fur- ther, its anterior glabellar bulb is wider and more in- flated than in any other material assigned to E. typi- calis. It has a prominent eye ridge, not visible on UI- rich’s photograph of E. typicalis or on any other spec- imens that have been assigned to the species. Finally, it has very small, subsemicircular palpebral lobes. Ad- ditional comparisons are made with other taxa below. The species from the Rabbitkettle Formation is known from three cranidia, two librigenae, and a py- gidium, all silicified (Ludvigsen, 1982, fig. S8K—W). It differs from the Whitehall species in the possession of an L1 that is subequal in width to L2, a considerably less laterally inflated anterior glabellar lobe, longer (exsag.) palpebral lobes, librigena with a much shorter genal spine, a pygidium with two as opposed to three clearly developed axial rings, and in the absence of distinct eye ridges. Caution must obviously be exer- cised in pygidial comparisons, as each species is rep- resented by only one specimen. However, work in progress on silicified faunas of the Notch Peak For- mation of western Utah indicates that in large pygidial samples of Eupytchaspis, there is no intrasample var- iation in axial ring number. Indeed, there is no docu- mented example of variation in this feature in any spe- cies of Euptychaspis. The two cranidia from the Mis- taya Formation of the southern Canadian Rocky Mountains illustrated by Westrop (1986b) are compa- rable in all available details to the Rabbitkettle material (including the presence of fine anastomosing sculpture at the base of the occipital spine) and may well prove conspecific. Euptychaspis dougali shares with the Whitehall spe- cies a pygidium with three distinct axial rings and a very similar librigena with a long genal spine. In ad- dition to its glabellar autapomorphies, E. dougali dit- fers in that its L1 is subequal to, or even narrower than, its L2, its anterior glabellar bulb is less inflated, it lacks eye ridges, it lacks a very sharp break in slope of the frontal area (demarcated in the Whitehall spe- cies by a prominent, transverse sculptural ridge), and it has longer, larger palpebral lobes with a much less prominent palpebral furrow. E. dougali can be differ- entiated from the Rabbitkettle species (in addition to its glabellar autapomorphies) in the possession of a more transverse versus more rounded anterior cranidial margin in dorsal view (this could be affected by dis- tortion of the Rabbitkettle specimens), relatively wider interocular fixigena, less well impressed palpebral fur- row, much longer genal spine, and a pygidium with three versus two axial rings. The pygidium of EF. dou- gali has a prominent median notch in its posterior mar- gin (PI. 6, fig. 44) that is not present in the Rabbitkettle specimen (Ludvigsen, 1982, fig. 58S), but this appar- ent difference could be influenced by photographic ori- entations and should be confirmed on the basis of ad- ditional specimens. Family ILLAENURIDAE Vogdes, 1890 Genus ILLAENURUS Hall, 1863 Type species.—Illaenurus quadratus Hall, 1863, p. 176. Illaenurus montanensis Kobayashi, 1935 Plate 7, figures 1-37, Plate 8, figures 1-35 Illaenurus montanensis Kobayashi, 1935, p. 48, pl. 10, figs. 1, 2; Westrop, 1986b p. 70, pl. 34, figs. 13-15 onymy). (see for complete syn- Diagnosis.—A species of I/laenurus with divergent anterior branches of facial sutures; in large individuals, width at anterior end of cranidium exceeds width across palpebral lobes. Discussion.—As revised by Westrop (1986b, pp. 69-71), Ilaenurus falls into two stratigraphically seg- regated groups of species that differ in cranidial length. A lower group, comprising /. priscus Resser, 1942, 18 BULLETIN 365 (Westrop, 1986b, pl. 34, figs.1—5) and /. holcus Wes- trop (1986b, pl. 34, figs. 6-10), is characterized by relatively short cranidia. The stratigraphically higher species, /. quadratus Hall, 1863, (Westrop, 1986b, pl. 33, figs. 1-7) and J. montanensis Kobayashi, 1935, (Westrop, 1986b, pl. 34, figs. 13-15) have longer cran- idia. The material illustrated here conforms to the cur- rent concept of ///aenurus montanensis by possession of strongly divergent, anterior branches of the facial sutures. Like cranidia from Alberta (Westrop, 1986b, pl. 34, fig. 14), width at the anterior end of the cran- idium of large individuals of /. montanensis from Ne- vada exceeds width across the palpebral lobes. Cran- idia from Alberta possess punctae along the axial fur- rows and frontal area that are absent from cranidia illustrated herein. //laenurus quadratus is character- ized by subparallel to weakly divergent anterior branches of the sutures and, consequently, the anterior portion of the cranidium is relatively narrower. Sclerites other than the cranidium have not been il- lustrated previously. Small librigenae (PI. 8, figs. 5, 12, 14-16) have long, gently curved genal spines and conspicuous, convex lateral borders. During ontogeny, this spine is reduced to a small, thorn-like structure (Pl. 8, figs. 1, 2, 4, 6) and is lost almost completely in the largest individuals (PI. 8, fig. 13). The lateral bor- der is lost posteriorly, but 1s retained as a rim anteri- orly (e.g., Pl. 8, figs. 1, 2, 10). The doublure is narrow, and at least one specimen (PI. 8, figs. 1, 7) suggests that a functional rostral suture was present. In contrast, I. priscus Resser (Westrop, 1986b, pl. 33, figs. 14, 15) appears to have had yoked cheeks. The pygidium of /. montanensis has not been de- scribed previously. It is subelliptical in outline, with length slightly less than 40 percent of maximum width, and is moderately convex, with height along midline (posterior view) a little less than 25 percent of pygidial width; anterior corners have well-defined articulating facets. The lateral profile is evenly curved upward. The axis is weakly convex and differentiated from the pleural field in posterior view only by a change in slope. The axial ring furrows are completely effaced. The pleural field is effaced except for one pair of pleu- ral furrows at anterior. The doublure occupies about 33 percent of pygidial length and maintains a roughly even width; the anterior margin is weakly undulose. The external surface of the pygidium is smooth except for terrace ridges near, and parallel to, the posterior margin. Figured material.—Thirteen cranidia (SUI 99124— 99137), eleven librigenae (SUI 99138-99149), one thoracic segment (SUI 99154), and five pygidia (SUI 99150-99153, 99155). Family CATILLICEPHALIDAE Raymond, 1937 Genus TRIARTHROPSIS Ulrich, in Bridge, 1931 Type species.—Triarthropsis nitida Ulrich, in Bridge, 1931, p. 214. Triarthropsis limbata Rasetti, 1959 Plate 9, figures 1—25, 28, 32, 33 Triarthropsis limbata Rasetti, 1959, p. 382, pl. 52, figs. 1-8; Lud- vigsen, 1982, p. 74, fig. 57U (see for complete synonymy). Figured material.—Seven cranidia (SUI 99156— 99161, 99170) and seven librigenae (SUI 99162— 99169). Discussion.—Wide fixigenae and, on several speci- mens, a poorly defined anterior border furrow, are shared with Triathropsis limbata Rasetti (1959, pl. 52, figs. 1-8). Rasetti’s types are variable in glabellar out- line but tend to have a somewhat more tapered anterior lobe than the cranidia illustrated herein. Rasetti (1959, p. 382) described faint median furrows on the anterior lobes of his specimens, although they are not evident in his photographs. Triarthropsis nitida Ulrich (in Bridge, 1931, pl. 19, figs 3, 4; Rasetti, 1959, pl. 55, figs. 6-13; Westrop, 1986b, pl. 39, figs. 8-13) has nar- rower fixigenae and lacks an anterior border and bor- der furrow. In addition, specimens from Pennsylvania (e.g., Rasetti, 1959, pl. 55, fig. 12) and Alberta (e.g., Westrop, 1986b, pl. 39, figs. 8, 10, 12) have paired tubercles on the fixigenae and glabella. Triarthropsis marginata (Rasetti, 1945, pl. 60, figs, 9-13; Ludvigsen et al., 1989, pl. 35, figs. 17-19), T. cf. marginata (Westrop, 1986b, pl. 39, figs. 6, 7) and T. casca Ludvigsen and Westrop (in Ludvigsen et al., 1989, pl. 35, figs. 20-27) all differ from 7. limbata in having much shorter frontal areas and palpebral lobes that are located close to the glabella. The poorly known 7. princetonensis Kobayashi, 1935, (Winston and Nicholls, 1967, pl. 11, fig. 26) differs from 7. limbata on the basis of the subrectangular glabella that is poorly differentiated from a short anterior border, and palpebral lobes that are centered opposite the S2 glabellar furrow, rather than the L2 lateral lobe. Librigenae (PI. 9, figs. 12-25) include some speci- mens that are yoked. They possess long genal spines and convex lateral borders that carry sculpture of coarse terrace ridges. The librigenal field is narrow and also carries terrace ridges. Similar librigenae have been attributed to T. nitida Ulrich (Rasetti, 1959, pl. 55, fig. 9; Westrop, 1986b, pl. 39, fig. 13), and those of Per- acheilus spinosus (Rasetti, 1945) (Ludvigsen er al., 1989, pl. 34, fig. 17) differ in having a shorter, more slender genal spine and a more convex librigenal field. Theodenisia gibba (Rasetti, 1944) (Ludvigsen ef al., 1989, pl. 32, fig. 10) has a librigena with sculpture of LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 19 coarse terrace ridges and a stout genal spine, but the lateral border is not differentiated from the librigenal field. Triarthropsis sp. | Plate 9, figures 26, 27, ?29, 30, 31, 34-38 Figured material.—Three cranidia (SUI 99171-— 99173) and three librigenae (SUI 99174—99176). Discussion.—A few cranidia differ from Triarthrop- sis limbata (P1. 9, figs. 1-11) in having a shorter fron- tal area and narrower preocular fixigenae. In these re- spects, they resemble cranidia of T. marginata (Rasetti, 1945, pl. 60, figs, 9-13; Ludvigsen er al., 1989, pl. 35, figs. 17-19), T. cf. marginata (Westrop, 1986b, pl. 39, figs. 6, 7), T. casca Ludvigsen and Westrop (in Ludvigsen et al., 1989, pl. 35, figs. 20-27) and 7. princetonensis Kobayashi, 1935, (Winston and Nich- olls, 1967, pl. 11, fig. 26). All of these differ from T. sp. 1, however, in having smaller palpebral lobes that are located very close to the glabella. In addition, the palpebral lobes of T. princetonensis are located farther forward on the cranidium and the anterior end of the glabella is poorly differentiated from the frontal area. Librigenae of T. sp. 1 (Pl. 9, figs. 34, 35, 37, 38) are similar to those of 7. limbata (PI. 9, figs. 12—25), dif- fering in possessing a much longer posterior segment of the the facial suture that corresponds to a wider posterior fixigena (Pl. 9, fig. 26, 27). Also, the border furrow of 7. sp. | is shallower than on similarly sized librigenae of 7. limbata. Family EUREKIIDAE Hupe, 1953 Discussion.—Ludvigsen and Westrop (in Ludvigsen et al., 1989) suggested that the Eurekiidae could be assigned to the Remopleuridoidea. Although some characters (e.g., size and position of the palpebral lobes) lend support to this view, new information on the structure of the thorax (PI. 11, figs. 30—35, Pl. 12, figs. 1-5) suggests that eurekiids are not remopleuri- doideans. Thoracic segments of Eurekia are strongly arched with a well-defined fulcrum and wide inner portion of the pleura; articulation is fulcrate. In con- trast, remopleuridoideans have a fulcrum close to the axial furrow and, consequently, very narrow inner por- tion of the pleura (Whittington, 1997); articulation in- cludes well-developed fulcral processes and sockets (Chatterton and Ludvigsen, 1976, pl. 1, figs. 16-19, 23, 25-29, 31, 49). The Eurektidae are regarded herein as of uncertain affinities. Although the broader relationships of the Eurekiidae are uncertain, they may be related to such Early Sun- waptan genera as Monocheilus Resser, 1937, and Stig- macephalus Resser, 1937. Westrop (1986b) considered such a relationship unlikely, but there are striking sim- ilarities in glabellar furrow morphology and size and position of the palpebral lobes between small cranidia of Monocheilos (e.g., Westrop, 1986b, pl. 15, figs. 7, 8) and eurekiids. Restudy of the poorly known Ma- ladia Walcott, 1924, generally regarded as an early member of the Eurekiidae (e.g., Longacre, 1970), may be helpful in evaluating eurekiid relationships. Genus EUREKIA Walcott, 1916 Type species.—Ptychoparia (Euloma)? dissimilis Walcott, 1884, p. 409 (see Taylor, 1978). Eurekia rintintini, new species Plate 10, figures 1-32, Plate 11, figures 1-35, Plate 12, figures 1-29 Diagnosis.—A species of Eurekia with sculpture of closely spaced, irregular, star-shaped tubercles over ex- ternal surface of cranidium, librigenal field, thoracic pleurae, and axis and pleural field of pygidium. Cran- idium with distinct preglabellar field that is subequal in length to anterior border. Large pygidium with five pairs of long, widely spaced, tapered marginal spines. Description.—Cranidium (excluding posterior fixi- genae) subrectangular in outline, with width between the palpebral lobes equal to cranidal length; maximum width across posterior fixigenae slightly more than 150 percent of width between palpebral lobes. Convex gla- bella raised well above level of palpebral lobes and occupies a litthke more than 80 percent of cranidial length; width is 55 percent cranidial width across pal- pebral lobes. Occipital ring raised above rest of gla- bella in lateral view; longitudinal profile of preoccip- ital glabella curved, with curvature increasing sharply in front of palpebral lobes. Glabellar outline subrect- angular; rounded anteriorly. Axial furrows firmly im- pressed and bowed gently outward, so that maximum glabella width is at SI furrow or L2 lobe. Occipital furrow well-incised groove, subtransverse medially but deflected forward near axial furrows; occipital ring oc- cupies slightly less than 25 percent of glabellar length. Firmly impressed S1 furrow curves backward and in- ward from axial furrow. L1 lobe subcircular in outline and slightly shorter than occipital ring; width equal to about 25 percent of glabellar length. S2 furrow as deep as, but less strongly curved than, S1 furrow. L2 lobe equal in length to occipital ring. Frontal lobe accounts for about 27 percent of glabellar length. Frontal area subequally divided into downsloping preglabellar field and upturned, triangular anterior border that is strongly arched in anterior view (PI. 10, fig. 4); anterior border furrow may be transverse (Pl. 10, figs. 1, 22), for- wardly curved (PI. 10, fig. 16) or bowed gently back- ward (Pl. 10, fig. 3). Interocular fixigenae narrow, roughly equal in width to palpebral lobe, and upwardly 20 BULLETIN 365 sloping. Palpebral lobe flat to gently upsloping, arcuate band centered opposite L2 lobe; extends from mid- point of L1 to posterior end of frontal lobe. Palpebral furrow finely etched groove. Anterior branches of fa- cial suture weakly convergent, nearly straight before swinging abruptly inward along anterior cranidial mar- gin. Posterior branches diverge at almost 90 degrees to axial furrow, then curve almost straight back. Pos- terior fixigenae narrow, nearly transverse bands flexed downward at about 45 degrees; bisected by firmly im- pressed posterior border furrow; posterior border ex- pands abaxially, so that distal width is twice width at axial furrow. Cranidial furrows, inner half of palpebral lobe and preglabellar field lack sculpture; glabella, fix- igenae, and anterior border carry sculpture of closely spaced, irregular, star-shaped tubercles; outer part of palpebral lobe has network of anastomosting ridges that produce an irregularly punctate appearance. Hypostome shield shaped in outline with width about 75 percent of length; posterior margin well rounded and anterior margin bowed gently forward. Convex, subelliptical median body divided unequally by barely perceptible median furrow into crescentic posterior lobe and roughly oval anterior lobe; latter accounts for about 60 percent of median body length. Lateral and posterior borders narrow, convex rims sep- arated from median body by finely etched border fur- rows; width of posterior border about 50 percent width of lateral border. Anterior border wall-like, directed ventrally well below level of adjacent portions of lat- eral borders. Anterior wings triangular in outline, flexed dorsally at about 30 degrees; width about 30 percent of hypostome length. Posterior wings narrow, vertically directed prongs with tips curved gently for- ward. Sculpture of terrace ridges confined to borders and anterior wings. Librigenae separated by median suture and carry small, thorn-like genal spine. Librigenal field tall, ac- counting for about 75 percent of librigenal field in lat- eral view, and slopes steeply downward from eye so- cle. Socle consists of two bands separated by shallow longitudinal furrow; upper band slightly narrower than lower band. Convex, tube-like border separated from librigenal field by broad, shallow border furrow; inner edge of doublure les beneath border furrow; panderian notch present near posterior end of doublure. Libri- genal field with sculpture of closely spaced, irregular, star-shaped tubercles and coarse, longitudinal ridges on border; doublure with fine terrace ridges. Thorax of at least 11 segments; tapers gradually backward, so that width at posterior is about 67 per- cent width at anterior. Axis occupies about 35 percent of segment width in dorsal view; strongly arched, ac- counting for about 45 percent of segment height in anterior view. Axial furrows shallow, ill-defined grooves. Subelliptical articulating half-ring depressed slightly below rest of ring: firmly impressed articulat- ing furrow transverse medially but curved forward near axial furrows. Pleura with well-defined fulcrum. Inner portion of pleura horizontal; outer portion slopes steeply downward from fulcrum to terminate at short, blunt spine. Well-incised, narrow, nearly transverse pleural furrow divides pleura into subequal anterior and posterior pleural bands; outer portion of anterior band with narrow, subtriangular facet. Facet and artic- ulating half-ring smooth; pleural spine with terrace ridges. Sculpture of closely spaced, irregular, star- shaped tubercles on remainder of segment. Pygidium subelliptical in outline, with length (ex- cluding marginal spines) slightly more than 50 percent of width; triangular facet at anterior corner. Five pairs of tubular marginal spines that decrease in size pos- teriorly; posteriormost pair about 33 percent of length of anteriormost. Spines become longer, more slender, distinctly tapered, more pointed, and more widely spaced during holaspid ontogeny (compare PI. 12, figs. 7, 8, 11, 15, 16 and Pl. 12, figs. 19-21, 23-27). Axis strongly convex, raised well above pleural field, and accounts for about 65 percent of pygidial height in posterior view; in dorsal view, occupies slightly less than 90 percent of pygidial length and about 33 per- cent of maximum pygidal width; tapers gradually backward, with width at anterior ring about 150 per- cent of width at terminal piece. Axial furrows broad, clearly defined grooves. Three axial rings and rounded terminal piece; anteriormost ring with conspicuous, semielliptical articulating half-ring and deep, trans- verse articulating furrow. Rings decrease in length pos- teriorly, so that first ring is almost twice length of third; terminal piece accounts for about 20 percent of axial length. Two anterior ring furrows firmly im- pressed, but third furrow shallower. Pleural fields con- vex, downsloping. Narrow, slot-like pleural and inter- pleural furrows become shallower and indistinct to- ward rear; only two pairs usually evident. Subequal anterior and posterior pleural bands usually evident only opposite first axial ring. Doublure narrow, with anterior edge extending to posterior end of axis. Pleu- ral field and axis with sculpture of irregular tubercles; marginal spines carry terrace ridges. Holotype.—A cranidium (SUI 99178; Pl. 10, figs. 2. 5, 8, 9) from the Bullwhacker Member, Windfall Formation, Barton Canyon, Cherry Creek Range. Figured material.—Twelve cranidia (SUI 99177— 99187, 99193), seven hypostomes (SUI 99188-99192, 99195, 99196), five librigenae (SUI 99194, 99197— 99200), one thoracopygon (SUI 99203), two isolated LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 21 thoracic segments (SUI 99201, 99202), and eight py- gidia (SUI 99204-99211). Etymology.—Named for Rin Tin Tin. Discussion.—Irregular, star-shaped turbercles simi- lar to those of Eurekia rintintini n. sp. are scattered over external surfaces of Eurekia sp. | from the Rab- bitkettle Formation of the Mackenzie Mountains (Wes- trop, 1995, pl. 6, fig. 1), although their true morphol- ogy cannot be determined on internal molds. Eurekia sp. | differs from E. rintintini in lacking a preglabellar field. Eurekia longifrons Westrop (1986b, pl. 6, figs. 1— 5), from the Mistaya Formation of Alberta, is the only other species with a distinct preglabellar field. This feature is relatively longer than that of EF. rintintini, and is equal to roughly twice the length of the anterior border. Eurekia longifrons also possesses convention- al, rounded tubercles on the cranidium and has nar- rower, less strongly curved palpebral lobes than E. rin- tintini. Pygidia of these two species possess similar marginal spines, but can be differentiated on the basis of sculpture. The type species of Eurekia, E. dissimilis (Walcott, 1884) (Taylor, 1978, text-fig. 1) from the Windfall Formation of Nevada, is much more strongly convex than E. rintintini, so that the anterior third of the glabella slopes steeply downward and partly over- hangs the anterior border. Eurekia ulrichi (Rasetti, 1945) (Ludvigsen, 1982, fig. 61A—Q), from northern and eastern Canada, has a finely tuberculate sculpture and lacks a preglabellar field. The pygidium of this species has shorter, less tapered marginal spines than E. rintintini, and has faint pleural and axial ring fur- rows posteriorly. The hypostome attributed to E. ul- richi is very similar to that of E. rintintini, and cor- roborates the assignment. Eurekia eos (Hall, 1863) (Taylor, 1978, pl. 1, figs. 1-17, pl. 2, figs. 1-17), a species that has been reported widely over North America, and E. bacata Ludvigsen (1982, fig. 62A—J), from the Rabbitkettle Formation of the Mackenzie Mountains, both differ from £. rintintini in lacking a preglabellar field. In addition, the pygidia are differ- entiated readily from E. rintintini. Eurekia eos has short, closely spaced, bluntly ended marginal spines (see also Westrop, 1986b, pl. 6, fig. 11), whereas E. bacata has a broad axis that overhangs the posterior pygidial axis. Finally, Eurekia plectocanthus Loch (in Loch ef al., 1993, fig. 6.2, 3, 5-7), from the Survey Peak Formation, Alberta, is based upon inadequate material and is probably best restricted to the types. It appears to have possessed an anteriorly rounded gla- bella that is quite different from the subquadrate gla- bella of E. rintintini. Genus CORBINIA Walcott, 1924 Type species.—Corbinia horatio Walcott, 1924, p. 55: Corbinia implumis Winston and Nicholls, 1967 Plate 13, figures 1-28 Corbinia implumis Winston and Nicholls, 1967, p. 86, pl. 9, fig. 3: Westrop, 1986b, p. 78, pl. 6, figs. 6, 7 (see for complete synon- ymy). Bayfieldia binodosa (Hall). Stitt and Straatman, 1997, fig. 9.17 (only). Diagnosis.—A species of Corbinia with coarsely granulose sculpture on cranidium: pygidium = with sculpture restricted to terrace ridges on or near mar- ginal spines. Only anterior axial ring and pleural fur- rows impressed firmly; remaining furrows shallow to barely perceptible. Terminal piece of axis has pair of gently rounded protuberances. Bluntly rounded mar- ginal spines are closely spaced. Description.—Cranidium (excluding posterior fixi- genae) subrectangular in outline, with width across palpebral lobes equal to about 95 percent of length; width across palpebral lobes 67 percent of width across posterior fixigenae. Glabella tapers forward, gently rounded anteriorly and slightly constricted at L1; occupies about 85 percent of cranidial length and 60—70 percent (lower values in smaller cranidia) of cranidial width between palpebral lobes; strongly con- vex and raised well above palpebral lobes in anterior view. Lateral profile of glabella curved, with occipital ring barely raised above level of L1; degree of cur- vature increases in front of palpebral lobes. Axial and preglabellar furrows narrow, but clearly defined, grooves. Occipital furrow firmly impressed, transverse medially but curved forward near axial furrow; bifur- cates distally, so that occipital ring is composite with small, gently inflated antero-lateral lobe. Occipital ring occupies about 17 percent of cranidial length. S1 and S2 lateral furrows are barely perceptible on even small cranidia (PI. 13, figs. 3, 4) and not expressed on ventral surfaces (Pl. 13, fig. 11). Short frontal area with dis- tinct preglabellar field equal to 20—30 percent of an- terior border length; border furrow may be transverse or bowed gently backward, so that outline of border may be subtriangular (Pl. 13, fig. 3) to transversely subelliptical. Border gently upturned in lateral view and moderately arched in anterior view. Palpebral lobes flat to weakly upturned, arcuate bands centered opposite L2; length decreases somewhat through ho- laspid ontogeny from 45 percent of glabellar length in smaller cranidia to 36 percent in large specimens. Pal- pebral furrow finely etched groove. Interocular fixi- genae narrow, equal in width to palpebral lobe: ante- rior and posterior tips of palpebral lobes separated Dp) BULLETIN 365 from glabella by very narrow strips of fixigenae. An- terior branches of facial sutures very weakly divergent before swinging inward along anterior cranidial mar- gin. Posterior branches initially weakly divergent be- fore diverging abruptly along nearly transverse path; swing backward at anterior tips of posterior fixigenae and are subparallel near posterior margin of cranidium. Posterior fixigenae narrow, nearly transverse bands flexed downward at about 45 degrees; bisected by firmly impressed posterior border furrow (shallower in largest cranidum); posterior border expands abaxially, so that distal width is twice width at axial furrow. Most small cranidia with sculpture of closely spaced, fine tubercles over entire surface; on largest cranidium (PI. 13, fig. 1), tubercles subdued, more widely scattered, and confined to glabella. Fixigenae separated by median suture and with very short, sharply pointed genal spine. Eye socle simple, arcuate band. Tall librigenal field slopes steeply down- ward from socle to broad, shallow anterior border fur- row. Anterior border convex, tubular; outer edge of doublure lies beneath border furrow and is deflected by panderian notch near posterior margin of librigena. Sculpture of closely spaced, fine tubercles on librigen- al field; coarse, longitudinal ridges on border. Pygidium subelliptical in outline with length slightly less than half of width; narrow, triangular facet at an- terior corner. Five pairs of short, bluntly pointed, closely spaced marginal spines that become progres- sively more curved inward and reduced slightly in size toward rear; posteriormost pair expressed only as rounded protuberances. Axis convex, gently tapered and long, occupying almost entire pygidial length; width at anterior ring about 35 percent of maximum pygidial width. Axis strongly convex, occupying about 75 percent of pygidial height in posterior view. Two axial rings and long terminal piece that carries pair of ill-defined, rounded protuberances at posterior; termi- nal piece occupies 40 percent of axis length. Anter- iormost ring includes conspicuous, semielliptical artic- ulating half-ring and firmly impressed articulating fur- row. Two transverse axial ring furrows; posteriormost very shallow and barely perceptible on some speci- mens. Pleural field flexed steeply downward, becom- ing flatter near margin. Two pairs of pleural furrows expressed as narrow grooves on most specimens; in- terpleural furrows weak. Subequal anterior and pos- terior pleural bands well defined opposite anteriormost axial ring, but indistinct on remainder of pleural field. Medially, outer edge of doublure reaches posterior end of axis; doublure expands abaxially, so that width at anterior corner of pygidium almost twice width behind axis. Surface smooth except for terrace ridges on and near marginal spines, doublure, and posterior tip of terminal piece. Figured material.—Four cranidia (SUI 99212-— 99215), one librigena (SUI 99216), and three pygidia (SUI 99217-99219). Discussion.—Westrop (1986b) restricted the type species of Bayfieldia, B. tumifrons Clark, 1924, to the incomplete holotype (Westrop, 1986b, pl. 6, fig. 8), and suggested that Bayfieldia binodosa (Hall, 1863) should be assigned to Corbinia Walcott, 1924. Pygidia (Hall, 1863, pl. 7, fig. 47) and cranidia (Clark, 1924, pl. 4, fig. 7; see Winston and Nicholls, 1967, p. 84 for discussion) of C. binodosa are preserved as sandstone internal molds and have never been illustrated photo- graphically, so that this species is difficult to interpret. Cranidia of C. implumis Winston and Nicholls (1967, pl. 9, fig. 3) are coarsely granulose, whereas cranidia from Texas (Winston and Nicholls, 1967, pl. 9, fig. 1) that have been attributed to C. binodosa are smooth. Although Longacre (1970; see also Stitt, 1971) argued that C. binodosa and C. implumis were synonyms, Westrop (1986b) suggested that the distinction be- tween them should be maintained. The material illus- trated herein supports the latter view. Cranidia (PI. 13, figs. 1-15) closely resemble the holotype of C. im- plumis (Winston and Nicholls, 1967, pl. 9, fig. 3), dif- fering only in having an anterior border furrow that is less strongly curved backward posteriorly. The coarse- ly granulose sculpture is retained through a broad size range, although it is more subdued in the largest (PI. 13, fig. 1, 15) and smallest (Pl. 13, figs. 4, 10) speci- mens. Pygidia of C. implumis have not been described previously but are quite distinct from those attributed to C. binodosa, including Hall’s (1863, pl. 7, fig. 47) type. On the dorsal surface (Pl. 13, figs. 18, 19, 21, 24), pygidia of the former species have one well-de- fined anterior axial ring, and a second ring that is sep- arated from the terminal piece by a faint ring furrow. Pleural furrows also become progressively effaced to- ward the rear. Expression of axial ring and pleural fur- rows is equally poor on ventral surfaces (PI. 13, fig. 27) and, therefore, these features will be ill defined on internal molds. In contrast, Hall (1863, p. 160) noted the presence of three axial rings and a terminal piece in the axis of C.? binodosa, and described well-defined ribs on the pleural field. Pygidia attributed to this spe- cies by other workers (e.g., Grant, 1965, pl. 15, fig. 18: Winston and Nicholls, 1967, pl. 9, fig. 2: Stitt, 1971, pl. 5, fig. 7) all possess three pairs of firmly impressed pleural furrows that define convex pleural bands. In addition, these pygidia are relatively narrow- er than those illustrated herein. Pygidia of the type species of Corbinia, C. horatio Walcott, 1924 (Westrop and Ludvigsen, 1986, fig. 2.6— LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 2.8), are closely comparable to those of C. implumis in the degree of effacement. Corbinia implumis has rounded, closely spaced marginal spines, whereas those of C. horatio are widely spaced and sharply pointed. In addition, C. horatio lacks the pair of round- ed protuberances that are present on the terminal piece of the axis of C. implumis (e.g., Pl. 13, figs, 18, 24), and the pleural field carries granulose sculpture. Cran- idia of C. horatio from Walcott’s type lot (Westrop and Ludvigsen, 1986, fig. 2.1, 2.2, 2.5, 2.9) are mostly ex- foliated, but demonstrate that the external surface of the fixigena, frontal area, and at least part of the gla- bella was smooth. This species is also unique in the very small size of the palpebral lobes (e.g., Westrop and Ludvigsen, 1986, fig. 2.9: Westrop, 1986b, pl. 5, fig. 15). Our cranidia of C. implumis cover a broad size range and demonstrate that the relative length of the palpebral lobe was reduced during holaspid ontog- eny. Only the largest cranidium (PI. 13, fig. 1) has a palpebral lobe that approaches the size of that of C. horatio. The cranidia of C. implumis show the bifurcating occipital furrow and inflated lateral portion of the oc- cipital ring (e.g., Pl. 13, fig. 3) that was included in the diagnosis of Bayfieldia by Longacre (1970, p. 36). However, the phylogenetic significance of this feature, which is poorly expressed in C. horatio, is unclear because it also occurs in “Bayfieldia” simata Winston and Nicholls, 1967, (especially ““B.”? simata “‘var. A” Winston and Nicholls, 1967, pl. 9, fig. 24 [regarded herein as a separate species]) and, apparently, Maladia Walcott, 1924 (Walcott, 1925, pl. 16, figs. 23, 24). Family ENTOMASPIDIDAE Ulrich, in Bridge, 1931 Genus HETEROCARYON Raymond, 1937 Type species.—Heterocaryon platystigma Ray- mond, 1937, p. 1119. Heterocaryon vargum Westrop, 1986b Plate 14, figures 1—33 Heterocaryon vargum Westrop, 1986b, p. 80, pl. 40, figs. 4-6 (see for complete synonymy); Loch et al., 1993, fig. 6.10. Figured material.—Five cranidia (SUI 99220— 99224), seven librigenae (SUI 99225-99230, 99232), and two pygidia (SUI 99231, 99233). Discussion.—Cranidia from the Bullwhacker Mem- ber (Pl. 14, figs. 1-16) are closely comparable to si- licified specimens from the Rabbitkettle Formation, northwest Canada (Ludvigsen, 1982, fig. 5SA—F, H, L) assigned to Heterocaryon vargum Westrop, 1986b, a species known from two cranidia from the Mistaya Formation of the southern Canadian Rocky Mountains. Nw Ww Pygidia illustrated herein (Pl. 14, figs. 26, 27, 29-33) are somewhat longer than those from the Rabittkettle Formation, and have a weak medial indentation (PI. 14, figs. 30, 33) in the ventral margin of the steeply sloping border. Ludvigsen (1982, fig. 55G) illustrated a single incomplete librigena. New material illustrated herein (Pl. 14, figs. 17-19) demonstrates that the spe- cies, like Bowmania (Pl. 16, figs 18, 21, 22; Ludvig- sen, 1982, fig. 54F; Westrop, 1995, pl. 14, fig. 5), pos- sessed yoked librigenae. Genus BOWMANIA Walcott, 1924 Type species.—Arethusina americana Walcott, 1884, p. 62. Discussion.—In his revision of the genus, Ludvig- sen (1982, p. 69) included the presence of marginal cephalic spines on the librigenae in the diagnosis of Bowmania. Bowmania lassieae n. sp. from the Bull- whacker Member at Cherry Creek has a fringe of closely crowded, very short spines, and possession of a row of elongate spines can now be interpreted as a probable autapomorphy of the type species, B. amer- icana (Walcott, 1884). Librigenae are unknown for other species currently assigned to the genus. Ludvig- sen (1982, p. 72) noted that highly spinose librigenae occurred with cranidia of Bowmania pennsylvanica Rasetti, 1959, in the Frederick Limestone of Maryland. The types of B. pennsylvanica, however, are from the Conococheague Formation and lack librigenae; crani- dia from the Frederick Limestone are poorly preserved and only “tentatively attributed to the species’ (Ra- setti, 1959, p. 396). Thus, the nature of the librigenae of B. pennsylvanica remains uncertain. The dorsal pygidial margins of B. americana (Lud- vigsen, 1982, figs, 53K, 54H—L: Westrop, 1995, pl. 14, figs. 7, 9, 11) and B. bridgei (Rasetti, 1952, pl. 117, fig. 13) have narrow, nearly continuous raised rims, composed of low, closely spaced subrectangular pleu- ral spines, and Ludvigsen (1982, p. 69) included this trait (misconstured as a “‘pygidial border’’) in his di- agnosis. In the pygidium of B. lassieae (Pl. 17, figs. 1-16, 18-20, 23, 25, 26, 28) the pleural spines are less crowded, and are similar to those of Heterocaryon var- gum (see above) (PI. 14, figs. 26, 29, 30-33). Bowmania lassieae, new species Plate 15, figures 1—30, Plate 16, figures 1-30, Plate 17, figures 1-16, 18—20, 23, 25, 26, 28 Diagnosis.—A species of Bowmania with a very subdued fringe of small spines along cephalic margin; occipital spine absent in all but smallest holaspids. An- terior cranidial border long, convex, with length roughly equal to occipital ring. Cranidial sculpture of closely spaced tubercles augmented by fine pits. Py- 24 BULLETIN 365 gidial border formed by incompletely fused, square- tipped marginal spines. Description.—Cranidium subtrapezoidal in outline, with forwardly curved anterior margin; length 80 per- cent of width across palpebral lobes, and maximum width across posterior fixigenae 125 percent of width at palpebral lobes. Posterior cranidial margin curved weakly (Pl. 15, fig. 1) to strongly (Pl. 15, fig. 2) back- ward, so that lateral tips of posterior fixigenae extend back slightly to well behind occipital ring. Glabella parallel sided and well rounded anteriorly, with length 67 percent of cranidal length and width 33 percent of cranidial width across palpebral lobes; strongly convex and stands well above level of fixigenae; in most spec- imens, accounts for about half of cranidial height in anterior view. Longitudinal profile of glabella weakly convex between occipital furrow and anterior tips of palpebral lobes, then sloping forward to become nearly vertical at preglabellar furrow. Axial and preglabellar furrows shallow grooves. Finely etched occipital fur- row is transverse medially but curved forward near axial furrow. Occipital ring accounts for slightly more than 20 percent of glabellar length; may bear large median tubercle or, in smallest individuals, minute, thorn-like occipital spine. Firmly impressed S1 furrow short and oblique, terminating close to axial furrow; S2 similar but more transverse. L1 about twice length of L2 and occupies about 20 percent of glabellar length; frontal lobe accounts for nearly 40 percent of glabellar length. Long frontal area with inflated, steep- ly sloping preglabellar field and shorter, gently convex anterior border; border occupies 33—40 percent of frontal area length. Anterior border furrow well-in- cised groove and curved forward, roughly parallel to anterior cranidial margin. Small, semicircular, gently upsloping palpebral lobe centered opposite L2 or, less commonly, S2 and equal to about 25 percent of gla- bellar length; differentiated from broad, gently inflated interocular fixigenae by change in slope. Convex pal- pebral ridge curved gently forward and reaches gla- bella near mid-length of frontal lobe. Anterior branch- es of facial sutures weakly convergent before swinging inward along anterior cranidial margin. Posterior branches moderately divergent, but curve inward at posterior border furrow. Posterior fixigenae with firmly impressed posterior border furrow and convex poste- rior border; near axial furrow, border equal to about seven percent of cranidal length and increases some- what in length distally. Surfaces of fixigenae and preg- labellar field finely pitted and carry closely spaced tu- bercles that are perforated by median pores in large cranidia. Similar tubercles present on glabella, anterior and posterior border and palpebral ridges, and _ scat- tered fine tubercles on inner part of palpebral lobe. Librigenae yoked anteriorly and carry long genal spines that curve gently outward and backward, and may be flexed upward distally; spine equal to 325 per- cent of length of librigenal field. Eye socle of two narrow bands separated by finely etched groove; upper band slightly smaller than lower band. Librigenal field tall, accounting for about 65 percent of librigenal height in lateral view, and slopes steeply downward from socle to borders. Lateral and posterior borders broad, shallow, confluent grooves. Lateral and poste- rior borders convex; doublure also convex and outer edge lies beneath border furrow. Librigenal field with pitted sculpture augmented with “pitted” tubercles similar to those on cranidium. Tubercles also present on lateral and posterior borders, and continue along proximal 33 percent of genal spine; remainder of genal spine finely granulose. Doublure carries fine terrace ridges. Thoracic segment with very long, gently inclined axial spine; spine about 14 times length of rest of seg- ment. Axis narrow, equal to slightly more than 20 per- cent of segment width, and convex, accounting for about 50 percent of segment height. Articulating half- ring slightly more than half of length of axial ring: articulating furrow transverse. Inner portion of pleura horizontal; outer portion flexed gently downward at fulcrum and teminates at slender spine. Pleural furrow transverse, finely etched groove and divides pleura into subequal anterior and posterior pleural bands. Pleurae and axial ring with sculpture of fine tubercles; tuber- cles present on proximal part of axial spine but grade into granulose scupture distally. Pygidium subelliptical in outline, with length about 50 percent of maximum width. Axis long and narrow, occupying about 80 percent of pygidial length and 25 percent of maximum pygidial width; convex, standing well above pleural field and accounting for about 60 percent of pygidial height. Six axial rings and rounded terminal piece; anterior ring with semielliptical artic- ulating half-ring, equal to about 50 percent of length of ring and transverse, finely etched articulating fur- row. Ring furrows also transverse and finely etched. Pleural fields weakly arched in posterior view; flat near axis but flexed gently downward distally. At least four pairs of well-incised pleural furrows define subequal pleural bands. Anterior furrow nearly transverse before curving gently backward near border. Other furrows are increasingly oblique toward rear, and posteriormost does not reach border. Interpleural furrows finely etched and parallel to pleural furrows. Pygidial rim formed by closely crowded, square-tipped pleural spines. Border descends steeply from rim. Doublure extends inward medially to posterior edge of axis, but widens abaxially to become about 200 percent of me- LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 25 dial width at anterior corners of pygidium. Sculpture of fine tubercles on axial rings and pleural bands; on some segments, sculpture is missing on some anterior pleural bands. Holotype.—A cranidium (SUI 99234; Pl. 15, figs. 1, 4, 7, 12, 13) from the Bullwhacker Member, Wind- fall Formation, Barton Canyon, Cherry Creek Range. Figured material.—Fifteen cranidia (SUI 99234— 99248, 99250), four librigenae (SUI 99251, 99253- 99255), one thoracic segment (SUI 99249), and nine pygidia (SUI 99256-99264). Etymology.—Named for Lassie. Discussion.—The type species of Bowmania, B. americana (Walcott, 1884) is known from a single cranidium from the Eureka mining district of Nevada. Specimens from various regions of Laurentia have been assigned to it, but more data from Nevada are required to properly evaluate the true range of varia- tion of the species. Material from elsewhere (Ludvig- sen, 1982, fig. S3K—S, fig. 54A—O; Westrop, 1995, pl. 14, figs. 1-14), is variable in sculpture, frontal area length, and glabellar proportions, but all cranidial morphs are characterized by the presence of an occip- ital spine and a shorter anterior border than B. lassieae; librigenae have fringe of long marginal spines (Lud- vigsen, 1982, figs. 53P, 54E G, M—O; Westrop, 1995, pl. 14, figs. 5, 12). The type lot of B. pennsylvanica Rasetti (1959, pl. 55, figs. 1-5) apparently varies somewhat in cranidial sculpture (Taylor in Taylor and Halley, 1974, p. 21), but all specimens are character- ized by very short anterior borders. The cranidum identified as B. cf. B. pennsylvanica by Taylor (in Tay- lor and Halley, 1974, pl. 2, figs. 12-14) also has a short anterior border, and the preglabellar field de- scends steeply from the anterior end of the glabella. Bowmania sagitta Winston and Nicholls (1967, pl. 10, figs. 19, 20) has a medially pointed anterior margin, which gives the cranidium a subpentagonal outline. The less crowded pygidial pleural spines separates the pygidium of B. lassiae (Pl. 17, figs. 1-16, 18-20, 23, 25, 26, 28) from all other species of the genus for which this sclerite is known (e.g., Rasetti, 1952, pl. 117, fig. 13; Ludvigsen, 1982, figs, 53K, 54H—-L; Wes- trop, 1995, pl. 14, figs. 7, 9, 11). Family PLETHOPELTIDAE Raymond, 1925 Discussion.—The most recent evaluation of the Plethopeltidae was presented by Ludvigsen and Wes- trop (in Ludvigsen er al., 1989, p. 56). Of the char- acters listed in their diagnosis, the terminations of the thoracic pleurae appear to be the most robust of the potential synapomorphies that define the group. Pleth- opeltis Raymond, 1913, has distinctive, square-tipped segments with ill-defined spines that appear to be con- tinuations of the anterior pleural bands (Ludvigsen er al., 1989, pl. 45, figs. 9-11, pl. 46, fig. 2, 3). Identical thoracic tips are present in Leiocoryphe Clark, 1924 (Ludvigsen ef al., 1989, pl. 48, fig. 11, pl. 49, figs. 7, 11, 12) and on all but the three anterior segments of Stenopilus pronus Raymond, 1924 (Stitt, 1976, pl. 2, fig. 1). A wide range of pygidia have been attributed to species assigned to Plethopeltis (e.g., Rasetti, 1959, pl. SSueses oy LOIS Stitt, lO IeypIo mites. 13.4: 18, pl. 8, fig. 14; Westrop, 1986b, pl. 36, figs. 7, 10, 12, 13, pl. 37, figs. 6, 8-10, 14, 15; Ludvigsen et al., 1989, pl. 45, figs. 2, 9, 10, pl. 46, figs. 12, 14, 18, 19), suggesting that the current classification captures only a fraction of the phylogenetic structure that might be retrieved from a detailed analysis of the Plethopeltidae. Recognition of Plethometopus Ulrich, in Bridge, 1931, and Plethopeltis as differently effaced grades, how- ever, as advocated by Loch ef al. (1993), does not address this issue and merely creates paraphyly in Plethopeltis. Further revision is needed, but is beyond the scope of this monograph. CHERRYCREEKIA, new genus Type species.—Cherrycreekia benjii, new species. Diagnosis.—A genus of? Plethopeltidae with cran- idial outline bluntly pointed at anterior. Librigenae with long, slender, outwardly curved genal spine. Py- gidium with short axis reduced to single axial ring and terminating at conspicuous ridge that is directed steep- ly upward and backward. Pleural and interpleural fur- rows absent. Etymology.—For the Cherry Creek Range. Bynumiella? oklahomensis Res- Assigned species. ser, 1942; Cherrycreekia benjii n. sp. Discussion.— Cherrycreekia resembles several var- iably effaced, mostly small and probably polyphyletic Sunwaptan trilobites, including Calvipelta Westrop, 1986b and Pugionicauda Westrop, 1986b. Westrop (1986b) initially assigned them to the family Kings- toniidae but later (Westrop, 1992) argued that differ- ences in the structure of the occipital ring cast doubt on a relationship with such genera as Kingstonia Wal- cott, 1924, and Bynumia Walcott, 1924. As discussed above, Calvipelta may prove to be an effaced eupty- chaspidine, but the affinities of Pugionicauda remain uncertain. Cranidia from the Mistaya Formation, Alberta, (Westrop, 1986b, pl. 41, figs. 11-13) are clearly con- specific with those illustrated herein (PI. 18, figs. 1— 23, 29, 30). In discussing the affinities of this species, Westrop (1986b) made comparisons with Acheilus Clark, 1924, (see Ludvigsen, 1986), but noted that dif- ferences in the size and position of the palpebral lobes 26 BULLETIN 365 made an assignment to that genus questionable. Also, the glabella of Achei/us is subrectangular in outline (Ludvigsen er al., 1989, pl. 37, figs. 6, 12), whereas C. oklahomensis (Resser, 1942) (Westrop, 1986b, pl. 41, fig. 8) has a glabella that is tapered anteriorly. Thus, while comparisons between effaced taxa are fraught with difficulty, the available information makes a close relationship between Cherrycreekia and Acheilus unlikely. Cherrycreekia is most likely a member of the family Plethopeltidae. The new silicified material (PI. 18, figs. 1—23) shows that the cranidial outline of Cherrycreek- ia is very similar to that of Plethopeltis (e.g., see Lud- vigsen, 1982, fig. 56T—V; Ludvigsen and Westrop, 1983b, pl. 19, figs. 1-5, 8, 9; Westrop, 1986b, pl. 36, figs. 1, 2, 14, 16, 17, 19, pl. 37, figs. 1-3, 11-13), and differs only in the bluntly pointed, rather than evenly rounded, anterior cranidial margin (e.g., Pl. 18, fig. 16) and the less divergent posterior branches of the facial sutures. The long, slender, outwardly curved genal spines differ from the short, stout spines that are de- veloped in Plethopeltis (e.g., Ludvigsen and Westrop, 1983b, pl. 18, figs, 7, 8, 13, pl. 19, fig. 10; Westrop, 1986a, pl. 36, fig. 5; Ludvigsen ef al., 1989, pl. 45, fig. 11, pl. 46, fig. 1): other plethopeltid genera possess rounded genal angles (e.g., Ludvigsen et al., 1989, pl. 47, fig. 3, pl. 48, figs. 3, 9, pl. 49, fig. 22, pl. 50, figs. 2): Square-tipped thoracic segments (Pl. 17, figs. 48, 49) similar to those of Plethopeltis and Leiocoryphe (e.g., Ludvigsen et al., 1989, pl. 45, figs. 9-11, pl. 46, fig. 2, 3, pl. 48, fig. 11, pl. 49, figs. 7, 11, 12) may belong to Cherrycreekia and provide strong support for an assignment to the Plethopeltidae. The pygidium of Cherrycreekia has a distinctive ridge at the posterior end of the short axial lobe that must have docked with the cephalic doublure during enrollment. Although a wide diversity of plethopeltid tails have been described (e.g., Rasetti, 1959, pl. 3, figs: 3; 5; 7; 13, 18; 19; 20; 21, 28-30; Sttt, 1971), pl. 4, fig. 10, pl. 6, figs. 13, 14, 18, pl. 8, fig. 14; Westrop, 1986b, pl. 36, figs. 7, 10, 13, pl. 37, figs. 6, 8, 9, 14; Ludvigsen ef al., 1989, pl. 45, figs. 2, 9, pl. 46, figs. 3, 12, 14, 18, 19, pl. 47, figs. 5, 6, 8, 9, 11-14, pl. 48, figs. 5, 18-20. pl. 49, figs. 3, 7, 11, 12, 19), none possesses a comparable structure. Ridge-shaped struc- tures that presumably functioned in enrollment also occur on pygidia of the euptychasidine, Euptychaspis (Pl. 6, figs. 37-39, 42—44; see also Taylor and Halley, 1974, pl. 2, fig. 11; Ludvigsen, 1982, fig. S8S—U; Wes- trop, 1995, pl. 7, fig. 21), but are much lower than in Cherrycreekia. In both genera, the down-sloping re- gion of the pygidium outside of the ridge is unfur- rowed, and carries a sculpture of anastomosing terrace ridges or coarser ridges. Despite these general similar- ities, we are confident the pygidium of Cherrycreekia is correctly assigned. Sclerites of Cherrycreekia do not occur in association with cranidia and librigenae of euptychaspidines. There are numerous differences in the structure of the cranidia and librigenae between Euptychaspis and Cherrycreekia, so that pygidial sim- ilarities are reasonably interpreted as homoplasious. It is also worth noting that several features of the pygid- ium of Cherrycreekia also occur in some plethopeltids, including the overall outline and the convex, down- sloping pleural field with sculpture of terrace ridges (e.g., Rasetti, 1959, pl. 53, figs. 17-19). Cherrycreekia benjii, new species Plate 18, figures 1—30, Plate 19, figures 1-11, 17, ?Plate 17, figures 48, 49 Acheilus? ct. oklahomensis (Resser, 1942). Westrop, 1986b, p. 83, pl. 41, figs. 11-13 (only; fig. 10 = Calvipelta spinosa). Diagnosis.—A species of Cherrycreekia with gla- bella effaced anteriorly and with long, slender occipital spine. Description.—Cranidium subrectangular in outline, with bluntly pointed anterior margin; width across pal- pebral lobes slightly greater than preoccipital length. Long, slender occipital spine directed gently upward at about 10 degrees and equal to at least 50 percent of preoccipital cranidial length. Lateral cranidial profile gently convex between occipital furrow and anterior tips of palpebral lobes, then slopes evenly downward at about 45 degrees to anterior cranidial margin. Cran- idial furrows largely effaced, with very shallow, sub- parallel axial furrows expressed only between poste- rior Margin and anterior tips of palpebral lobes. Gla- bella moderately arched posteriorly, occupying about 60 percent of width between palpebral lobes, but un- differentiated from fixigena in front of palpebral lobes. Faint, transverse occipital furrow evident on most specimens; occipital ring subtriangular, length (exclud- ing spine) equal to slightly more than 25 percent of preoccipital cranidial length. Palpebral lobes semiellip- tical flaps, horizontal or gently down sloping; differ- entiated from down-sloping interocular field centered slightly behind cranidial mid-length; length equal to about 75 percent of occipital ring length. Anterior branches of facial sutures initially subparallel, then curve smoothly inward to become nearly tranverse at midline; posterior branches diverge for short distance before becoming subparallel. Posterior fixigenae sub- triangular in outline and flexed downward at about 45 degrees; posterior border furrow obsolete. External surface of cranidium smooth. Librigena with long, stout, gently tapered, slightly LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP DF, advanced genal spine curved outward and backward: length about 160 percent length of remainder of libri- gena. Eye socle composed of two parallel bands sep- arated by shallow, transverse groove; upper band somewhat smaller than lower band. Librigenal field slopes steeply downward almost to cranidial margin: lateral border very narrow rim separated from libri- genal field by finely etched groove. Doublure narrow, gently convex and maintains even width. External sur- face of librigena smooth, except for coarse terrace ridges on border. Pygidium subelliptical in outline, with length about 80 percent of maximum width; strongly convex, with distinct arch in posterior margin; lateral margins straight, oblique, and broad posterior margin well rounded. Axis very short, equal to about 25 percent of pygidial length, and bounded posteriorly by tall, wall- like ridge extending upward and backward to termi- nate well above level of axis; in posterior view, ridge has inverted v-shape. Single transverse axial ring and subequal articulating half-ring with gently curved an- terior margin; articulating furrow shallow, nearly transverse groove. Pleural field unfurrowed and flexed steeply down to posterior margin; border and border furrow absent. Doublure narrow, gently convex and maintains even width along posterior margin; length equal to 10 percent of pygidial length. Pleural field with sculpture of anastomosing terrace ridges; ridge at end of axis may have small node at apex. Holotype.—A cranidium (SUI 99276; Pl. 18, figs. 1, 2, 5, 10, 12) from the Bullwhacker Member, Wind- fall Formation, Barton Canyon, Cherry Creek Range. Figured material.—Eight cranidia (SUI 99276— 99282, 99286), three librigenae (SUI 99284, 99285, 99287), three pygidia (SUI 99288—99290) and, possi- bly, one thoracic segment (SUI 99268). Etymology.—Named for Benji. Discussion.— Cherrycreekia oklahomensis (Resser, 1942) (Westrop, 1986b, pl. 41, figs. 8, 9; see also Stitt, 1971, pl. 7, fig. 15) differs from C. benjii n. sp. in the absence of an occipital spine, and by possession of a more nasute anterior cranidial margin. Cherrycreekia oklahomensis is also less effaced, so that the glabella is outlined completely by axial and preglabellar fur- rows on both the dorsal surface of the exoskeleton (Stitt, 1971, pl. 7, fig. 15) and on internal molds (Wes- trop, 1986b, pl. 41, figs. 8, 9). Faint S1 lateral furrows and a more firmly impressed occipital furrow are pres- ent, as are palpebral ridges. As discussed above, cranidia from the Mistaya For- mation, Alberta, assigned by Westrop (1986b) to Ach- eilus cf. oklahomensis (Resser, 1942), are unquestion- ably conspecific with C. benji. Westrop (1986b, pl. 41, fig. 10) also attributed a small, exfoliated pygidium with a long axis to this species, but it most likely be- longs to Calvipelta spinosa Westrop, 1986b, which oc- curs through the same stratigraphic interval (Westrop, 1986b, fig. 31). GLABERASPIS, new genus Type species.—Glaberaspis scoobydooi, new spe- cles. Diagnosis.—A blind, isopygous genus of ?Pletho- peltidae with semielliptical pygidium with long, nar- row axis that consists of four axial rings and terminal piece. Convex cranidium with conspicuous occipital ring that is curved strongly backward. Where evident, glabella is forwardly tapered and subtriangular in out- line. Etymology.—From glaber, hairless, bald, smooth, and aspis, shield, in reference to the strongly effaced cranidium of this species. Assigned species.—Leiocoryphe occipitalis Rasetti, 1944: Leiocoryphe longiceps Rasetti, 1963; Bynumiel- la vescula Stitt, 1971; Glaberaspis scoobydooi n. sp. Discussion.—In their revision of the plethopeltid genera, Ludvigsen and Westrop (in Ludvigsen ef al., 1989) assigned Leiocoryphe occipitalis Rasetti and L. longiceps Rasetti only questionably to that genus in the absence of information of the pygidium. Cranidia of both of these species, and a related new species from the Bullwhacker Member, differ from those of Leiocoryphe in possessing conspicuous, backwardly curved occipital rings. The new species has a pygidi- um (PI. 19, figs. 24-39) that differs markedly from all previously described plethopeltid pygidia, and pro- vides the basis for the establishment of a new genus. The pygidium of Glaberaspis scoobydooi n. gen. and sp. is semielliptical in outline, with a long, well-de- fined axis that consists of four axial rings and a ter- minal piece. Cranidia and pygidia show a comparable size range, suggesting that it was isopygous. In con- trast, Leiocoryphe is micropygous with an effaced len- ticular pygidium whose axis is broad and convex (Lud- vigsen et al., 1989, pl. 48, fig. 11, pl. 49, figs. 3, 4, 7, Nils 1D), Although the dorsal surface of the cranidium of Glaberaspis is effaced, the ventral surface of the exo- skeleton shows the barely perceptible outline of an an- teriorly tapered, subtriangular glabella (Pl. 19, figs. 16, 19; the dark, triangular areas near the posterior mar- gins of the cranidia are shadows created by flash pho- tography). Taylor (1976) suggested that Bynumiella vescula Stitt (1971, pl. 7, figs. 16-18) should be as- signed at least questionably to Leiocoryphe. The well- defined occipital ring and anteriorly tapered, subtrian- gular glabella, however, both suggest that this species 28 BULLETIN 365 is related to G. scoobydooi. Differences between these two species are discussed below. Like Leiocoryphe and Glaberaspis, Meniscocoryphe Ludvigsen and Westrop (in Ludvigsen er al., 1989) is blind, and possesses broad, short, transversely semi- elliptical pygidia. Although expressed only on the ven- tral surface of the exoskeleton, the long, narrow axis of Mensicocoryphe (e.g., Ludvigsen et al., 1989, pl. 49, fig. 19) appears to consist of at least four segments and, in this respect, resembles the pygidium of Gla- beraspis. Pygidia of Meniscocoryphe (e.g., Stitt, 1971, pl. 4, fig. 10; Westrop, 1986b, pl. 38, fig. 21; Ludvig- sen et al., 1989, pl. 49, figs. 19, pl. 50, fig. 3) encom- pass a similar size range as associated cranidia and it is possible that this genus, like Glaberaspis, was iso- pygous. Both Stenopilus and Plethopeltis differ from Gla- beraspis in possessing eyes. Cranidia of Stenopilus (e.g., Ludvigsen et al., 1989, pl. 47, figs. 1-4, 7, 16— 22, pl. 48, figs. 1-3, 8, 9, 13-16) are comparable to Glaberaspis in the degree of effacement, but are more strongly arched longitudinally. The effaced pygidia of Stenopilus are typically short and possess broad, con- vex axes (e.g., Ludvigsen et al., 1989, pl. 47, figs. 5, 6, 9, 12-14, pl. 48, figs. 4-6, 12). The glabella of Plethopeltis is defined by axial furrows at least pos- teriorly and, where fully expressed, is very gently ta- pered and rounded anteriorly (e.g., Ludvigsen and Westrop, 1983b, pl. 18, figs. 1-3, 9, 12, pl. 19, figs. 1, 6, 8, 11, 13). In late meraspids of Plethopeltis has- tatus (Westrop, 1986b, pl. 38, fig. 14), however, the glabella is subtriangular in outline, and resembles Gla- beraspis much more closely. Although most species of Glaberaspis possess posteriorly rounded occipital rings, G. cf. G. occipitalis from the Shallow Bay For- mation (Ludvigsen ef al., 1989, pl. 49, figs. 17, 18) has a tapered, posteriorly pointed occipital ring and distinct occipital furrow that closely resembles those of some species of Plethopeltis (e.g., Westrop, 1986b, pl. 36, figs, 8, 9, pl. 37, fig. 6; Ludvigsen er al., 1989, pl. 46, figs. 6, 8, 13) In the absence of information on the thoracic seg- ments, assignment of Glaberaspis (and Meniscocory- phe) to the Plethopeltidae must be tentative. It is also worth making comparisons with Clelandia Cossman, a genus whose affinities are currently uncertain. Wes- trop (1986b) commented on the similarities between some species of this genus and G. vescula. The gla- bella of the type species, C. typicalis (Resser, 1942) (Westrop, 1986b, pl. 41, figs. 20-30) is strongly ta- pered and subtriangular in outline. Lateral glabellar furrows are effaced on the external surface of the exo- skeleton but, as in G. vescula (e.g., Stitt, 1971, pl. 7, figs., 17, 18), they are expressed on internal molds as ill-defined pits that are connected across the glabella by a shallow furrow (e.g., Westrop, 1986b, pl. 41, figs. 23, 24). Pygidia of Clelandia are quite different from those of Glaberaspis or any other plethopeltid (Nor- ford, 1969). Glaberaspis scoobydooi, new species Plate 19, figures 12—16, 18-39 Diagnosis.—A_ species of Glaberaspis with con- spicuous, posteriorly rounded occipital rings that lacks an occipital furrow. Glabella is poorly defined on ven- tral surface of exoskelton. Description.—Cranidium subelliptical in outline, with width between posterior corners of fixigenae 90— 95 percent of length; strongly convex with highest point at posterior end of occipital ring: lateral profile gently curved upward and steeping in slope along an- terior third of cranidium. All cranidial furrows com- pletely effaced on dorsal surface; strongly tapered, subtriangular glabella outline barely perceptible on ventral surface. Occipital rings conspicuous, occupy- ing about 30 percent of cranidial length and about 70 percent of maximum cranidial width; posterior margin curved strongly backward. Palpebral lobes absent. In dorsal view, sutures converge forward in smooth curve. In anterior view, each branch of the sutures ap- pears gently curved upward, meeting on midline, so that anterior tip of cranidium is pointed (PI. 19, fig. 20). External surface of cranidium is smooth. Pygidium semielliptical in outline with length 67— 80 percent of maximum width (lower proportions in smaller pygidia). In posterior view, axis and pleural fields weakly arched, with very weakly concave lateral margins descending steeply. Axis long, narrow, ta- pered gradually backward, and gently convex, occu- pying 33-43 percent of pygidial width at anterior (lower proportions in smaller pygidia), and nearly 95 percent of pygidial length in dorsal view. Axial fur- rows very shallow grooves. Axial rings and ring fur- rows ill defined on dorsal surfaces of larger pygidia; ventral surfaces of larger pygidia and dorsal surfaces of some small individuals show four axial rings and rounded terminal piece separated by nearly transverse axial furrows. Pleural field crossed by faint, oblique pleural furrows. Border in form of narrow rim at base of steeply descending flanks of pygidium. External surface of pygidium is smooth. Holotype.—A cranidium (SUI 99291; Pl. 19, figs. 12, 14, 19, 20) from the Bullwhacker Member of the Windfall Formation, Barton Canyon, Cherry Creek Range. Figured material.—Three cranidia (SUI 99291— 99293) and five pygidia (SUI 99294-99298). Etymology.—Named for Scooby-Doo. LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 29 Discussion.—The conspicuous, well-rounded occip- ital ring of Glaberaspis scoobydooi is shared with G. occipitalis (Rasetti, 1944), a species that has been re- ported from the south-central United States (e.g., Bell and Ellinwood, 1962; Stitt, 1971) and eastern Canada (Rasetti, 1944; Ludvigsen ef al., 1989). However, all cranidia assigned previously to the latter species (Bell and Ellinwood, 1962, pl. 59, fig. 4; Stitt, 1971, pl. 4, fig. 13; Ludvigsen et al., 1989, pl. 49, figs. 15, 16) possess a well-defined occipital furrow on both testate and exfoliated surfaces, whereas the furrow is absent on G. scoobydooi. In addition, the occipital ring 1s the most elevated portion of the cranidium of G. scooby- dooi (Pl. 19, figs. 14, 18, 21), whereas stereopairs of G. occipitalis (e.g., Stitt, 1971, pl. 4, fig. 13) indicate that the central portions of the cranidium are strongly convex and are elevated above the occipital ring. Gla- beraspis cf. G. occipitalis from the Shallow Bay For- mation of western Newfoundland (Ludvigsen ef al., 1989, pl. 49, figs. 17, 18) has a tapered, posteriorly pointed occipital ring and distinct occipital furrow, and probably represents an undescribed species. Glaber- aspis longiceps (Rasetti, 1963, pl. 130, figs. 21-26) has a relatively narrower cranidium than G. scooby- dooi and is much more convex, so that the anterior end slopes almost downward in lateral view. In addi- tion, an occipital furrow is expressed on at least larger individuals (Rasetti, 1963, pl. 130, fig. 25). Glaberaspis vescula (Stitt, 1971, pl. 7, figs. 16-18: see also Taylor, 1976, pl. 3, fig. 21) bears a superficial resemblance to G. scoobydooi, but shows an anteriorly tapered glabella on testate (Stitt, 1971, pl. 7, fig. 16) and exfoliated surfaces (Stitt, 1971, figs. 17, 18; Wes- trop, 1986b, pl. 41, fig. 31). Stitt (1971, p. 23) de- scribes “‘very faint” palpebral lobes and furrows, al- though they are not evident in his photographs (1971, pl. 7, figs. 16-18). Examination of the holotype (OU 6519) and paratypes (OU 6520, OU 6521), housed at the Oklahoma Museum of Natural History, showed that these features are not present. The apparent de- flection in the suture on the left side of the holotype (Stitt, 1971, pl. 7, fig. 16) is actually a broken surface, and the sutures form a smooth curve in lateral view. At least parts of the lateral cranidial margins of the paratypes have been damaged during preparation and do not show the true course of the facial sutures. Family UNCERTAIN GEN. AND SP. INDET. Plate 17, figures 51—53 Figured material.—One cranidium (SUI 99275) Discussion.—A single cranidium is characterized by a narrow, convex, gently tapered, anteriorly rounded glabella with three pairs of shallow lateral furrows. Palpebral lobes are long, extending from the occipital furrow to the S3 furrow, and are separated from nar- row fixigenae by finely etched palpebral furrows. The short frontal area lacks an anterior border and border furrow. The long palpebral lobes invite comparison with genera of the Dikelocephalidae or, perhaps, Eureki- idae. However, dikelocephalids typically possess con- spicuous, transglabellar S1 furrows throughout the ho- laspid ontogeny (e.g., Pl. 2, figs. 2, 13, 15, 34), where- as the cranidium described herein has weak lateral fur- rows only. Some eurekiids have lateral furrows that approach those of our cranidium (e.g., Ludvigsen, 1982, fig. 61 A—F), but those species with long palpe- bral lobes are characterized by very narrow interocular fixigenae (e.g., Westrop, 1986b, pl. 6, fig. 15). UNASSIGNED SCLERITES Plate 17, figures 17, 21, 22, 24, 27, 29—47, 50 Discussion.—Thoracic segments with narrow pleu- rae and extremely long axial spines (PI. 17, figs. 17, 21, 22, 24, 27, 29, 30, 34, 36) are presumably from the posterior part of a thorax. Similar segments occur at the end of the thoraces of articulated individuals of ‘ukonaspis from the lower Bullwhacker Member at Cherry Creek (Adrain and Westrop, unpublished data), although other sclerites of this genus have not been recovered from the samples described herein. Hypostomes have been attributed to very few Sun- waptan trilobites. Eurekiid (Ludvigsen, 1982; Pl. 11, figs. 1-11), plethopeltid (Westrop, 1986b, pl. 36, fig. 3, pl. 37, fig. 16; Ludvigsen er al., 1989, pl. 46, fig. 15) dikelocephalid (PI. 1, figs. 5, 6, 8; Ulrich and Res- Ser 1933, pla26) foaG) pls siltaio 2 pla Sonos» ple 30; fis. 135 ple 37, nes 37Shergold WOON ple 3: tie: 11, pl. 4, figs. 7, 14, 20) and ptychaspidid (Lochman and Hu, 1959, pl. 58, fig. 25; Westrop, 1986b, pl. 7, fig. 9, pl. 8, figs. 4, 16) hypostomes have been docu- mented and, on this basis, the specimens illustrated herein are unlikely to belong to Prosaukia, Eupty- chaspis, Sunwaptia, Corbinia, Cherrycreekia or Gla- beraspis. The hypostomes are similar in outline, convexity and shape of the median body, expression of the me- dian furrow and the morphology of the lateral and pos- terior borders. They differ in size and position of the anterior and posterior wings. On the basis of size, the larger specimens illustrated herein (PI. 17, figs. 33, 35, 37, 40, 42, 45) might belong to ///aenurus montanen- SIS. A single pygidium (Pl. 17, figs. 31, 38, 43) is con- vex with a well-defined axis of three rings and a ter- minal piece, weakly furrowed pleural field, narrow 30 BULLETIN 365 posterior border and a well-defined median embay- ment of the posterior margin in posterior view. Only two genera, Triarthropsis and Gen. Uncertain, are po- tential candidates for this pygidium, as all others occur with pygidia that are assigned with confidence. Al- though a wide variety of pygidia have been attributed to catillicephalids (e.g., Ludvigsen ef al., 1989, pl. 32, figs. 21, 22, 28, 29, pl. 34, figs. 13, 28, 29, pl. 35, fig. 7), the specimen illustrated herein is unlikely to belong to either species of Triarthropsis present in our col- lections. The pygidia associated with holotype of T. limbata Rasetti in Virginia (Rasetti, 1959, pl. 52, figs. 5-8) are quite different, with long, multi-segmented axes and pleural fields traversed by up to six pairs of firmly impressed pleural and interpleural furrows. The pygidia that occur with cranidia of 7. nitida Ulrich (Rasetti, 1959, pl. 55, figs. 6-8) are comparable to those of 7. limbata and are unlike our specimen. As noted earlier, under the discussion of Prosaukia oldyelleri, dikelocephalid thoracic segments (Pl. 17, figs. 41, 46, 50) are left unassigned because they pos- sess sculpture of coarse granules that is not matched in either of the species described herein. A librigena (Pl. 17, fig. 47) also belongs to a dikelocephalid tri- lobite but differs from those of P. oldyelleri (Pl. 2, figs. 35, 37-39; Pl. 3, figs. 33, 41) in having a shorter, more slender and rapidly tapering genal spine. REFERENCES CITED Adair, D.H. 1961. Geology of the Cherry Creek District. 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Intermountain Association of Petroleum Geologists Guidebook to the Geology of east-central Ne- vada. — 7 a >=, of an a ee a - a : - > 7 = _ a - a - _ a Oo a — a ee - a a - —_ : 7 a —— oe ——- daar oe LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP PLATES ee) Nn 36 BULLETIN 365 EXPLANATION OF PLATE 1 Figure Less I>26Dikelocephalus minnesotensissOweny kSo2a iene cused neler ences eateries aie area ene oa aura ite ite mene) ayiaitel chee ence 10 I—4. Cranidium, SUI 99042, dorsal, left lateral, anterior, and ventral views, * 15. 5, 6, 8. Hypostome, SUI 99043, ventral, right lateral, and posterior views, <4. 7, 10. Lett librigena, SUI 99044, external and internal views, X12. 9. Left librigena, SUI 99045, external view, = 10. 11. Right librigena, SUI 99046, external view, * 12. 12. Right librigena, SUI 99047, external view, < 10. 13, 18, 22, 23, 26. Pygidium, SUI 99048, dorsal, posterior, oblique, lateral and ventral views, <3. 14, 15, 21. Thoracic segment, SUI 99049, dorsal, right lateral, and anterior views, 7.5. 16, 17, 20. Thoracic segment, SUI 99050, dorsal, right lateral, and anterior views, 7.5. 19, 24, 25. Pygidium, SUI 99051, dorsal, posterior, and right lateral views, < 10. BULLETINS OF AMERICAN PALEONTOLOGY, BULLETIN 365 PLATI BULLETINS OF AMERICAN PALEONTOLOGY, BULLETIN 365 PLATI Figure LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP EXPLANATION OF PLATE 2 l=30), Prosmiga Olean! DESY SIRI, Soocc ean sdoouweeebuovubobeoagronamanogo boon Udnu oon ooo oo abasaonauaanoaen 1, 5, 8, 12. Cranidium, SUI 99052, dorsal, left lateral, anterior, and oblique views, <4. , 6, 9. Cranidium, SUI 99053, dorsal, left lateral, and anterior views, <7.5 Cranidium, holotype, SUI 99054, ventral, dorsal, right lateral, and anterior views, «7.5 2 By 4s a Wile , 14, , 18, 5 7, 25% uh wee m2. 30, 29, 35) 16. 19. 21 31. 33. 28. 36. 34. Cranidium, Cranidium, . Cranidium, Cranidium, Cranidium, Cranidium, Cranidium, Cranidium, SUI 99055, SUI 99056, SUI 99057, SUI 99058, SUI 99059, SUI 99060, SUI 99061, SUI 99062, dorsal, left lateral, and anterior views, *7.5. dorsal, anterior, and right lateral views, 7.5. dorsal, left lateral, and anterior views, 10. dorsal, right lateral, and anterior views, <7.5. dorsal, left lateral, and anterior views, 15. left lateral, dorsal, and anterior views, *7.5. dorsal, right lateral, and anterior views, 7.5. anterior, left lateral, and dorsal views, <7.5. Right librigena, SUI 99063, external view, <7.5. 37-39. Left librigena, SUI 99064, external, ventrolateral, and internal views, *7.5. 38 BULLETIN 365 EXPLANATION OF PLATE 3 Figure Page —4ileeProsaukiavoldyellerismew SpeCles ya taart mle eibeo crorai ota Oo ICI orc imrusn tit) DsSicIGIOED 21, 24-26. cranidium, holotype, SUI 99092, oblique, dorsal, left lateral, and anterior views, 7.5. 40 BULLETIN 365 EXPLANATION OF PLATE 5 Figure Page I-32.) Sunwaptias plutou new SPEClES. ty ope: coes sles ch ou ci aileiten eiea te rcteinc. selunce ere oeebeotu ett) NS) crash oie cr-teerteagel cue eyewear eae see ene pie a teen ekg ee 13 1, 2. 4, 5. Cranidium, SUI 99093, dorsal, ventral, anterior, and right lateral views, * 15. 3, 6, 7. Cranidium, SUI 99094, dorsal, anterior, and right lateral views, x 10. 8, 9, 12. Cranidium, SUI 99095, dorsal, anterior, and left lateral views, *20. 10, 11; , 16. Left librigena, SUI 99098, external and internal views, * 10. . Left librigena, SUI 99099, external view, * 12. . Left librigena, SUI 99100, external view, * 10. . 25, 29. Pygidium, SUI 99101, dorsal, right lateral, and posterior views, * 10. . 26, 30. Pygidium, SUI 99102, dorsal, right lateral, and posterior views, x 10. 14, 17. Cranidium, SUI 99096, dorsal, anterior, and right lateral views, *15. 15, 18. Cranidium, SUI 99097, dorsal, anterior, and left lateral views, 12. 23, 27, 31. Pygidium, SUI 99103, dorsal, left lateral, and posterior views, * 10. , 28, 32. Pygidium, SUI 99104, dorsal, right lateral, and posterior views, X12. BULLETINS OF AMERICAN PALEONTOLOGY, BULLETIN 365 PLAT! BULLETINS OF AMERICAN PALEONTOLOGY, BULLETIN 365 PLATE 6 LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 4] EXPLANATION OF PLATE 6 Figure Page [SAAD hy CRASPUNAOU 2 GLMMEWESPECCICS Map saete ees ssc) 1 | Giishee sac) sadics tds e aeelec ete eases au eve) suepayisl eva Ao 40 acs aye athe She. # schus & wie iiss Gr oh Seer caense 1S 1, 5, 11, 12, 22. Cranidium, holotype, SUI 99105, dorsal, anterior, oblique, right lateral, and ventral views, < 12 , 3, 6, 9. Cranidium, SUI 99106, dorsal, ventral, anterior, and left lateral views, * 12. = 4, 7, 10. Cranidium, SUI 99107, dorsal, anterior, and left lateral views, * 12. 8, 14, 16. Cranidium, SUI 99108, dorsal, anterior, and left lateral views, * 10. 13, 17, 18. Cranidium, SUI 99109, dorsal, left lateral and anterior views, = 10. 15, 20, 21. Cranidium, SUI 99110, dorsal, anterior, and right lateral views, * 12. 19. Left librigena, SUI 99111, external view, = 10. 23, 25, 26. Left librigena, SUI 99112, external, ventrolateral, and internal views, 24. Left librigena, SUI 99113, external view, 10. 27. Right librigena, SUI 99114, external view, * 10. 28-30. Cranidium, SUI 99115, dorsal, right lateral, and anterior views, < 10. 31. Left librigena, SUI 99116, external view, 10. 32. Right librigena, SUI 99117, external view, 10. 33. Left librigena, SUI 99118, external view, 12. 34-36. Cranidium, SUI 99119, dorsal, anterior, and left lateral views, * 12. 37, 42, 43. Pygidium, SUI 99120, dorsal, left lateral, and posterior views, < 15. 38, 39, 44. Pygidium, SUI 99121, left lateral, dorsal, and posterior views, x 10. 40. Left librigena, SUI 99122, external view, * 10. 41. Left librigena, SUI 99123, external view, *20. x10. 42 BULLETIN 365 EXPLANATION OF PLATE 7 Figure Page 1=37, Ulaenurus, montanensis Kobay ashy plOS5 eves eiecs os se ist at eye eect ie © olen ele pe aie austere tice, Ch aleiey = coer pe ewe ere a 17 1, 2, 6, 7, 10. Cranidium, SUI 99124, dorsal, ventral, left lateral, anterior, and oblique views, *7.5. 3. Cranidium, SUI 99125, dorsal view, *7.5. 4, 8, 12. Cranidium, SUI 99126, dorsal, anterior, and right lateral views, * 10. 5. 9, 14. Cranidium, SUI 99127, dorsal, left lateral, and anterior views, 4. 11, 13. Cranidium, SUI 99128, dorsal and right lateral views, * 10. 15, 22. 25. Cranidium, SUI 99129, dorsal, left lateral, and anterior views, 7.5. 16, 17, 23. Cranidium, SUI 99130, dorsal, anterior, and right lateral views, 10. 18-20. Cranidium, SUI 99131, anterior, left lateral, and dorsal views, *7.5. 21. Cranidium, SUI 99132, dorsal view, *7.5. 24, 28. Cranidium, SUI 99133, left lateral and dorsal views, * 10. 26, 27, 29. Cranidium, SUI 99134, right lateral, dorsal, and anterior views, 10. 30, 31, 37. Cranidium, SUI 99135, left lateral, dorsal, and anterior views, *7.5. 32, 33. Cranidium, SUI 99136, dorsal and right lateral views, *7.5. 34-36. Cranidium, SUI 99137, right lateral, anterior, and dorsal views, * 10. BULLETINS OF AMERICAN PALEONTOLOGY, BULLETIN 365 TINS OF \MERICAN PALEONTOL( IGY, BULLI PLATE 8 LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 43 EXPLANATION OF PLATE 8 Figure : Page LESS ML GenunUShriOflanensiseWoODAyAashinnl OS a seiseatey caer a ricied uence aerate cles ester = fo) clonal) ele otie\ =. stv, s)celepcieusys, <=) si) siete easo oe inci oe 17 1, 7, 10. Left librigena, SUI 99138, external, internal, and ventrolateral views, *7.5. 2. 4. Left librigena, SUI 99139, external and internal views, 7.5. 3. Left librigena, SUI 99140, external view, * 10. 5. Left librigena, SUI 99141, external view, * 10. 6. Right librigena, SUI 99142, external view, *7.5. 8. Left librigena, SUI 99143, external view, *7.5. 9. Right librigena, SUI 99144, external view, *7.5. 11. Right librigena, SUI 99145, external view, *7.5. 12. Left librigena, SUI 99146, external view, < 10. 13. Right librigena, SUI 99147, external view, < 10. 14, 16. Right librigena, SUI 99148, external and ventrolateral views, 10. 15. Left librigena, SUI 99149, external view, * 10. 17, 18, 22. Pygidium, SUI 99150, dorsal, right lateral, and posterior views, <6. 19, 21, 25. Pygidium, SUI 99151, posterior, dorsal, and left lateral views, <5. 20, 23, 24, 28. Pygidium, SUI 99152, dorsal, posterior, left lateral, and ventral views, *7.5. 26, 27, 32. Pygidium, SUI 99153, left lateral, dorsal, and posterior views, *7.5. 29, 30, 35. Thoracic segment, SUI 99154, dorsal, anterior, and right lateral views, * 10. 31, 33, 34. Pygidium, SUI 99155, right lateral, dorsal, and posterior views, * 10. 44 Figure 1-25 ils Ze 26, 2 26, Zi; 29. 34. 35; St BULLETIN 365 EXPLANATION OF PLATE 9 228.325 09 irlartnropsis: limbaravRasettial.O59 sec cet) netey ste) at ae Ne sade eee eee PR Teen See) alceo eel tte ce nk ak 2. 6, 11. Cranidium, SUI 99156, dorsal, ventral, left lateral, and anterior views, 10. Cranidium, SUI 99157, dorsal view, 10. . 5, 10. Cranidium, SUI 99158, dorsal, left lateral, and anterior views, * 10. . Cranidium, SUI 99159, dorsal view, *15. . Cranidium, SUI 99160, dorsal view, * 10. . Cranidium, SUI 99161, dorsal view, «10. . Right librigena, SUI 99162, external view, 10. . 15. Left librigena, SUI 99163, external and internal views, < 10. . Left librigena, SUI 99164, external view, * 10. . 20, 23. Yoked librigenae, SUI 99165, dorsal, right lateral, and anterior views, * 10. , 21, 24. Yoked librigenae, SUI 99166, dorsal, left lateral, and anterior views, * 10. , 19. Right librigena, SUI 99167, external and internal views, «10. 2. Right librigena, SUI 99168, external view, * 10. . Right librigena, SUI 99169, external view, * 10. , 32, 33. Cranidium, SUI 99170, dorsal, anterior, and left lateral views, < 12. Ths WOW EE Sil see haliaiigbaycs llbsoedecdecncodau dense onemotonboonh bugaboo conGoonepoDoMDObOC TO SES 30, 36. Cranidium, SUI 99171, dorsal, ventral, and left lateral views, 10. 31. Cranidium, SUI 99172, dorsal and left lateral views, * 15. Cranidium, SUI 99173, dorsal view, * 10. Left librigena, SUI 99174, external view, *17. 38. Right librigena, SUI 99175, external and internal views, 10. Right librigena, SUI 99176, external view, 15. BULLETINS OF AMERICAN PALEONTOLOGY, BULLETIN 365 PLATE 9 BULLETINS OF AMERICAN PALEONTOLOGY, BULLETIN 365 PLATE 10 LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 45 EXPLANATION OF PLATE 10 Figure Page IB 2B UKE Ki GMTIME WAS PCCIES saiewem nia yetii-tc = cis, che rie) shen | LLETINS OF \ MERIC AN PALEONTOLOGY, BULLETIN 365 PLATE ] 2) LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP 47 EXPLANATION OF PLATE 12 Figure 1-5. Thoracopygidium, SUI 99203, dorsal, ventral, oblique, posterior, and left lateral views, * 15. 6, 9, 10. Pygidium, SUI 99204, dorsal, right lateral, and posterior views, = 10. 7, 8, 13. Pygidium, SUI 99205, dorsal, posterior, and left lateral views, *7.5. 11, 12, 15, 16. Pygidium, SUI 99206, dorsal, right lateral, posterior, and ventral views, *5 (note inverted cranidum of Bowmania lassieae n. sp. visible in fig. 16). 14, 17, 18. Pygidium, SUI 99207, dorsal, right lateral, and posterior views, < 10. 19, 23. Pygidium, SUI 99208, dorsal and posterior views, 10. 20, 24, 25. Pygidium, SUI 99209, dorsal, posterior, and right lateral views, * 10. 21, 26, 27. Pygidium, SUI 99210, dorsal, posterior, and right lateral views, * 12. 22, 28, 29. Pygidium, SUI 99211, dorsal, posterior, and right lateral views, < 10. A8 Figure 1-28. Corbinia implumis Winston and Nicholls, 1967 4.6 , 20. i Dwell 355 1, 8 9 1 BULLETIN 365 EXPLANATION OF PLATE 13 12, 14, 15. Cranidium, SUI 99212, dorsal, ventral, right lateral, anterior, and oblique views, *4. . 13. Cranidium, SUI 99213, dorsal, anterior, right lateral, and oblique views, X10. . Cranidium, SUI 99214, dorsal, anterior, and right lateral views, * 10. 0. Cranidium, SUI 99215, dorsal, anterior, and left lateral views, x 10. Right librigena, SUI 99216, external and internal views, * 10. , 25. Pygidium, SUI 99217, right lateral, dorsal, and posterior views, <6. , 24, 26, 27. Pygidium, SUI 99218, dorsal, right lateral, oblique, posterior, and ventral views, 5. , 28. Pygidium, SUI 99219, dorsal, left lateral, and posterior views, <5. BULLETINS OF AMERICAN PALEONTOLOGY. Bt LLETIN 365 PLATI 13 BULLETINS OF AMERICAN PALEONTOLOGY, BULLETIN 365 PLATE 14 Figure 1-33. il, 3) LATE CAMBRIAN TRILOBITES OF NEVADA: ADRAIN AND WESTROP EXPLANATION OF PLATE 14 EACLE OCOMy ON BUG CUTAN CS LLOD Lo 8 OD mere eg Meee te ke arme ttre ahs aiey oe eat New, ercliel x fetseiiera dedeuslea emer’ ct aug) aris tue) ais ote Soe one ZO , 14-16. Cranidium, SUI 99220, dorsal, left lateral, anterior, oblique, and ventral views, * 10. 2, 6, 10. Cranidium, SUI 99221, dorsal, right lateral, and anterior views, * 10. 3, 7, 8. Cranidium, SUI 99222, dorsal, anterior, and right lateral views, x 10. 4, 9. Cranidium, SUI 99223, dorsal and anterior views, < 10. 11-13. Cranidium, SUI 99224, anterior, left lateral, and dorsal views, * 12. 17— 20. 21, 23. 24. 25. 26, 28. 29, 19. Yoked librigenae, SUI 99225, anterior, right lateral, and dorsal views, 12. Left librigena, SUI 99226, external view, *15. 22. Left librigena, SUI 99227, external and internal views, «15. Left librigena, SUI 99228, external view, * 12. Left librigena, SUI 99229, external view, 10. Right librigena, SUI 99230, external view, 10. 27, 30-32. Pygidium, SUI 99231, dorsal, ventral, posterior, right lateral, and anterodorsal views, Left librigena, SUI 99232, external view, X12. 33. Pygidium, SUI 99233, dorsal and posterior views, 10. «10. 49 50 BULLETIN 365 EXPLANATION OF PLATE 15 Figure Page 1—30! Bowmania lassieaemew Species ra = = sere ielcns excnteeteneais caer eae ee 10 TALON ASDISii-h- tone 18 eer te doe Remo S te Teoh ous uC Cre eee 4 Me lleninayg Mey : aeyseee seater eg i teens ho heye (k-th eee ee tenuisculpta, Calvinella PRCOdERISIO S92 Fcc eos cq Meats ah ay suees Ue Lape he, ines) ech ete eS XA ela ky ma OMe EM Gag eogneuodasGauavoddacacs 12 LVIQTINVODSIS eaghcOa tester a, Ore seca oe peeo negate 15S 6327 FUINIFTONS RDB GYILELALG fepe este) oti eget s aaen ene iene ere 19 typicaliss Clelandia® ww. ees 25 typicalis, Euptychaspis 3, 14 ULFiCAUSEULTEKIG: yeh cute os sock cy th eitehaie ek ek nee eee 18 VAI QUM: LCLEFOCATYONE sj nis. -.tonsae aio: cheney sek civ seer ene 20 VESCUIG, GIADETASPIS facet ieee eee oe ce oe ae 24, 26 WhitehallvRonmattoness.) checrersrens cies etal eee eee 14 WalbernssBormationt © scsyc cs a, a chun, eevee © aueien eee aie a ceew en aeeaeees Sl. 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Begun in 1895 NUMBER 366 FEBRUARY 25, 2004 The Genus Lepicythara (Gastropoda: Turridae) from the Neogene and Pleistocene of Tropical America by Peter Jung Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York 14850 U.S.A. | y ISSN 0007-5779 ISBN 0-87710-459-X Library of Congress Control Number: 2003106843 Note: Beginning with issue number 356, Bulletins of American Paleontology is no longer designating volumes. The journal will continue to publish approximately 2—4 issues per year, each of which will continue to be individually numbered. Printed in the United States of America Allen Press, Inc. Lawrence, KS 66044 U.S.A. CONTENTS JNIDSTURS?: 5 5:8: 6 415 Bip. 5G HES Aye ee REIS CAE, HieM cpt ORG En cree Sue SNCME tS eg oS 5 FRCS TIN CUM ere eee cae warranty Remsets cpa Uae sner er ener sienna cP aych se RCSA ZguRNe ie cite ay aidan dsc Sen laVE EIS oe diag ee ees =) NATTA CU OT Mae Were uP Wee Wee Weve oe Merce ayaa ell Caleta NG. al cen eresh atm MeN Seo cs eacte afiane el vallty yar yh, aateds chia ow aguas SEe ae 5) NC OWIEUSCIMEN ES ey ert gary uss Sway ed ee ec cerey eaet epics es eli odeps Berks EMOTE AOE Lee cee rudy e wieehenmeuasie 6 Distibuitonkihroushmimesyan dks paccanmer errr er ee rr eer rc eiee re cing ire ye es eae ee eee 6 PAT CRUMCLE BN OM VAT ORS DECCLESH A ere yeyteleg Ve ueyeretat Cede vel os ssa tenehe remo essa reuse tuck SP Neiees f PIR Sass lef axe: evapo. te- enSuesere cheno o Systematic Paleontology IMItLOGUGT One epee tocr wer ree eee ania te RT ca eke eaten ATA WR MAAR cay ae mAbs 9 JN STOTRE NAA WIGIING: os ea eB G'S se SIS: Bac aoe Et ct ORT OP OMI Eas et Meee Cn an 9 DIAM OST CRLCAMITCS gree, Mer Pe fest tyareke ucts Ne co taye RTE POV ros SRSA SE ae Chr Te aes SHAK, Shae hia wit ays aatindans 11 Genuselepi cy inarat@|Ssompll9 OA meee ae heespe eae see ere ee ST eT see te erorcul iow achece eustoxotels Cie itil We DUGY LHATARDGSILESSG’ (Gardner) seca sea aeINee Te ee ee eee hen a caer icmers cues ener Roeser 13 ER COTILOTONEHSISE (@lSSOM) eee ars fe caer ART ue uehe lec) eee kaos o ee En ONE Ue IO OE ER 16 EEC OSTORICETISTSA (@1S SOM) ope Ruse cee ciores ace ea oe ee TEV eI ARS TONNE Re oy Sonate Ruehe lees 18 PaaS OSTANEGETSISN (@1SSOM) borates Merete ee esto te eet ST A ES OTR Ee eesot eee Fagen MS EMCES CLUS Com (UNI 8) etry crete gra LRN epee Rosin SIN Se ay RIO Cece WON PT ys IE Oe et ae 25 Ih, LADUE OO (GEV) 8) Gras cheese pesto RO ear er eet ee Rig PT eee Ia eee ie STE 28 pac iaelic piaeorian (Graloty) were ece seven sts hse CR ASO eS Pesan ahs eoeotiars eee oe ae 31 Pematiem epic Orie (Galo) espera erie ee eek oko oe ee Soe eer RS SU ay eit st eans llc sactcg see gaucrate exe lei asc atee 33 TERRES CLES USMIUMS DMR: Meese rates sPau eed ee straps eas Soa ee ses ORO Ts STOTT Cs AT as i RR 34 Dag: UQFDATO IE We SOS" cr octet ows MRS ON EAE CREME REREEP ORICA ace SE EE TEMPTS IPR RE EE GE UE et COUR RA 36 1 ey. Cikes UO LA AOU TON Wei) Ola ra as pr clac gee RCE Tae eT REC OE ee OS eevee ot a PR ea age 39 EM RATALGES CLUS QUIMARST) erry sey PESOS ToS. Bocce ce tay ones Sites epee ooh Tete eae a ne | Ge Os ere ae 40 Ibn. JUDG OTG (GED) - a: Ser thesos eee RRP EOE ETE eR ee OLA ee REN OP Pn Doe eee Spal ere oie 43 JES CCAIR COMDY scat S eoeace rene RHO aCe ron Raia See REPRE ee RACE a RTE TSE tT trai on Tet? 52 IE, HORDANGIS OE OS dG BRO 05-2 Ce eRe en eI PIE OC TOIATER OTe Choco crear eset atone ee 61 EMLL UT UC Cm INT ATES 11.6] Cll) eee rene pet cys ta citss arcane aa ener eae a eee SOA one) Hc oe Ee Ah ci enieiciee 64 Pmatiemicenritca NIAMS TI CLA) Aes amin ner weet te ect eS ore = my eee Stepanek ee OOS 66 EC DUG LELATLGS [) el NW ree RPE RR AS Uo EN oe, eM A EOE eS EN ITT ee th ata 68 JEG RES UNCN ACL ON BOR er een wie oc ore Cente Renee oe POOP OE AAC NE ROSES OE TO a OLE eo 68 LQ ENANOTE oye el aco Be Coe OTE LORS CAT OTC EECA ORER CEE TOUR ee ETE NCEE CAEP R oper ciere rene 70 EG MESMMG EP GOs 1D) sts neem petites: OG reciente REO MERC aE Ree Ra CCRC OR IO I eT: 70 HET) ICN LAT CES) WE MPM Tate Lee oN Fe sare OM ee So Ree Sa Oo ARI eNO eo EI OER Ne eae: 70 RET CLE NCOP Mae Ne a MRr Mcrae ieee alesis) SSSR hone ord ae aeng cise Rn md REL ae Reed Ble noel ate Guseas IMEC SSG hatte O Chalet ee 71 /NYO) BISSAU 0 eee Ste 00.55 ce Ne CER CE eee eR 72 AND DSMGIDS ILL a B'S oe Gee Grce Grey ee eek eRe MORE RC ne eC PS ee nee eer eee ee 73 Ni Gl xa a NS ty. Ss 898 oe al nnd ek cede Pe ec ered Re a epatate Lite a enn Oe Wee are, ene a ees a FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG THE GENUS LEPICYTHARA (GASTROPODA: TURRIDAE) FROM THE NEOGENE AND PLEISTOCENE OF TROPICAL AMERICA PETER JUNG Natural History Musuem Basel, Augustinergasse 2, CH-4001 Basel, Switzerland ABSTRACT The shallow to moderately deep water turrid genus Lepicythara is restricted to the Neogene and Pleistocene of tropical America including Florida. So far the genus consists of 22 species, twelve of which are specifically identified, five are identified by means of open nomenclature, and five are characterized by letters. Four species are described as new: L. higensis from the Pleistocene of Pacific Costa Rica, L. lJopenzana from the late Early to Middle Miocene Baitoa Formation of the northern Dominican Republic, L. paradisclusa trom the Early Pliocene Springvale Formation of the Central Range of Trinidad, and L. toroensis from the Early Pliocene Shark Hole Point Formation of the Valiente Peninsula, Province of Bocas del Toro, Panama. The geographic distribution of the species is irregular. Of the 13 areas of occurrence six are situated in Panama and Costa Rica. The amount of material assigned to individual species is also most irregular: only one species (L. polygona) is very well represented, two species (L. costaricensis and L. terminula) are well represented, but all the other species have to be called rare or extremely rare. The species diversity through time is fluctuating. After a period of low diversity during the late Early and Middle Miocene the diversity reached a maximum during Late Miocene times. In the Early Pliocene it was still fairly high, but during Middle and Late Pliocene times there was a steady decrease in diversity, the genus Lepicythara seemingly became extinct toward the end of the Pleistocene. RESUMEN El genero marino Lepicythara (Turridae) vivia en agues de poca hasta mediana profundidad y su distribution se limitaba al Neogeno y Pleistoceno de la America tropical, includido la Florida. Hasta ahora, el genero se compone de 22 especies, de las cuales 12 son identificadas especificaments, 5 se caraterizan por la monemclatura abierta, y las otras 5 por letras. Cuatro especies son nuevas. L. higensis del Pleistoceno de la parte pacifica de Costa Rica, L. lopenzana de la formacio Baitoa (ultima parte del periodo temprano del Mioceno, hasta lost principios del periodo medio de dicha epoca) de la Republica Dominicana del norte, L. paradisclusa de la formacio Springvale (Plioceno temprano) de la Central Range de Trinidad, y L. toroensis de la formacion Shark Hole Point (Plioceno temprano) do la peninsula Valiente, Provincia de Bocas del Toro, Panama. La distribucion geografica de las especies es irregular. De las 13 regiones, en las cuales se conoce Lepicythara, seis se encuentran en Panama y Costa Rica. Respecto a la frecuencia de los especimenes, solo una especie (L. polygona) es muy bien representada, dos especies (L. costaricensis y L. terminula) son bien representadas, y las otras especies son raras hasta muy raras. Principiando en el Mioceno tardio inferior, la diversidad de las especies Ilego a su maximo durante el Mioceno superior. En el Plioceno temprano, la diversidd todavia era relaiveamente considerable, per durante la epoca del Plioceno medio y tardio ocurrio una disminucion, u el genero Lepicythara evidentemente resulto extinto a finales del Pleistoceno. INTRODUCTION The turrid genus Lepicythara Olsson is by no means common where it occurs. A total of only 176 lots have been available for this study (Table 1). This material can be subdivided into three categories: 1) borrowed from other institutions (60 lots) 2) collections in the Naturhistorisches Museum Basel, Switzerland (NMB) (70 lots) 3) collections of the Panama Paleontology Project (PPP) (46 lots) The NMB material contains 47 lots from the Domin- ican Republic, 12 from Trinidad, 5 from Costa Rica, 3 from Ecuador, and 3 from Florida. The PPP material contains 24 lots from Panama, 19 from Costa Rica, and 3 from Ecuador. Not only is the material of Lepicythara rather scarce, but the species diversity is not great either. Out of the 22 species discussed in this report only three are represented by a reasonable amount of material; all the others are rare or extremely rare. Table | lists these species, and the number of the available lots and spec- imens is indicated for each. By far best represented is L. polygona; it is followed by L. costaricensis and L. terminula. After these three species the number of available specimens drops dras- tically. Twelve species are positively identified, five are identified by means of open nomenclature, and five are characterized by a letter. Four species are described as new. They are: L. higensis, L. lopezana, L. para- disclusa, and L. toroensis. For details of lithostratig- raphy, exact geographic location of occurrences, and precise stratigraphic position of localities reference is made to Coates (1999a—c). 6 BULLETIN 366 Table 1.—Total number of lots and specimens of species of Lep- icythara discussed in this paper. Number Number of Species of lots specimens basilissa 5 11 camaronensis 7 18 costaricensis 35) 138 cf. costaricensis | 1 disclusa 8 29 heptagona 10 16 ct. heptagona ] 2 aff. heptagona l 5 higensis 5) 15 lopezana 4 6 cf. lopezana 2 5 paradisclusa 5 26 polygona 40 1184 terminula 29 136 toroensis 3 7 turrita ts) 34 aff. turrita 3 4 sp. A 3} 3} sp. B ] 4 sp. 3 3 sp. D | 1 sp. E | i Total 176 1649 ACKNOWLEDGMENTS I would like to thank Antoine Heitz, preparator, and René Panchaud, collections manager, both of the Basel Natural History Museum, for their continued help dur- ing the preparation of this paper. Severino Dahint, pho- tographer at the museum, I would like to thank for his excellent work. Richard Guggenheim, who was in charge of the Scanning Electron Microscope Labora- tory of the University of Basel, gave permission to use his equipment. I would like to thank Dan Miller and Pascal Tschudin for their help in making the Scanning Electron Microscope photographs. In addition I am in- debted to Szuszi Thommen for her translation of the abstract into Spanish. Finally | owe much to a number of persons for the loan of relevant specimens: Roger Portell and Kathie Weedmann of the Florida Museum of Natural History, Division of Invertebrate Paleon- tology, Gainesville, Florida: Jann Thompson, Warren Blow, Tyjuana Nickens, and M.G. Harasewych of the National Museum of Natural history, Washington, D.C.; Elana Benamy and Gary Rosenberg of the Acad- emy of Natural Sciences, Philadelphia: and Wendy Taylor and Warren Allmon of the Paleontological Re- search Institution, Ithaca, New York. DISTRIBUTION THROUGH TIME AND SPACE The genus Lepicythara is known only from the Western Hemisphere. Its rather spotty occurrences in tropical America and Florida are shown in Text-figure 1. Below follows a list of the species discussed in this paper arranged by countries: Southern Florida, U.S. A. L. basilissa L. terminula L. turrita Eastern Haiti L. cf. lopezana Northern Dominican Republic L. heptagona L. lopezana L. polygona Trinidad L. disclusa L. paradisclusa Northern Colombia L. cf. Heptagona Northwestern Ecuador L. camaronensis Lasps Panama L. costaricensis cf. costaricensis . toroensis aff. turrita sp. A SUSU Is 2 sp. B Jé, So, (e Costa Rica L. costaricensis L. higensis JE, kyo) 1D) Southern Mexico L. aft. heptagona The greatest diversity (seven species) occurs in Pan- ama. On the other hand only one species each is re- corded from eastern Haiti, northern Colombia, and southern Mexico. Two species each are recorded from Trinidad and northwestern Ecuador, and three each from Florida, the northern Dominican Republic, and Costa Rica. Thus, the distribution and diversity are rather uneven. The species of Lepicythara are part of shallow to moderately deep water assemblages (Jack- FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG q Text-figure 1—Map showing areas of occurrence of species of Lepicythara. 1, northern Florida; 2, southern Florida; 3, eastern Haiti; 4, northern Dominican Republic; 5, Trinidad; 6, northern Colombia; 7, Esmeraldas area, northwestern Ecuador; 8, Darien, eastern Panama; 9, Canal area, Panama; 10, Bocas del Toro Province, northwestern Panama: 11, Limon Basin, Caribbean Costa Rica; 12, Golfo Dulce, Pacific Costa Rica; 13, Puntarenas Province, Pacific Costa Rica; 14, Santa Rosa, Veracruz, Mexico. son et al., 1999, table 3, p. 204, appendix 1, pp. 212— 213; for details see Appendix II). The stratigraphic ranges of the species are shown in Text-figure 2. The species diversity through time is visualized in Text-figure 3: after a hesitant beginning in Late Early and Middle Miocene times, the diversity increases rapidly to its maximum during Late Miocene times. During the Early Pliocene the diversity is still quite large, but after that there is a steady decrease until the genus disappears toward the end of the Pleis- tocene. Text-figure 3 resembles the analogous representa- tions for genera of the Strombina-group (Jung, 1989, fig. 28), and it is especially similar to the genus Sin- cola. There are, however, two basic differences: first the genus Lepicythara did not survive the Pleistocene, and second there is not a “bottleneck”” during Middle and Late Pliocene times in Lepicythara, whereas the genera of the Strombina-group all show it. In Lepicyt- hara there is a gradual decrease from the Middle Pli- ocene to the Pleistocene. i) The following list is a summary of the distribution of the 22 discussed species through time and space: L. basilissa: Shoal River Formation (Middle Mio- cene), northern Florida L. camaronensis: Onzole Formation (Early Plio- cene), northwestern Ecuador L. costaricensis: Rio Banano, Cayo Agua, and Shark Hole Point formations (all Pliocene), Carib- bean Costa Rica and Province of Bocas del Toro, Panama L. cf. costaricensis: Nancy Point Formation (Late Miocene), Province of Bocas del Toro, Panama L. disclusa: Melajo Clay Member of Springvale Formation (Early Pliocene), Trinidad L. heptagona: Cercado and Gurabo Formations (Late Miocene), Dominican Republic L. cf. heptagona: Late Miocene, northern Colom- bia . L. aff. heptagona: beds of Late Miocene age, Ve- racruz, Mexico 5.1 11.3 14.4 24.6 BULLETIN 366 Q n o i B oO a) 5 Sooo doe os 3 Se -_ © = o o> 2 oO & 633 88a8€ se g2e2 24% Spey SS Eee IO fa a ee (oh, TS Ce Oe SR RS in) ue tee ete Se (7) = = = Ones 2 5 Ses 2s Gane a ooo ole oS aoe Holocene / Recent Pleistocene se | m4] late middle —| Pliocene | i Hiaudl Haid Higddd ‘ | ih I PErirrridd 4 i middle i | —| Miocene if early Text-figure 2 L. higensis: Pleistocene, Pacific coast of Costa Rica L. lopezana: Baitoa Formation (late Early to early Middle Miocene), Dominican Republic. L. cf. lopezana: Thomonde Formation (late Early to early Middle Miocene), Haiti L. paradisclusa: Springvale Formation (Early Pli- ocene), Trinidad L. polygona: Cercado and Gurabo Formations (Late Miocene to Early Pliocene), Dominican Republic L. terminula: Pliocene Florida to Pleistocene, southern 2.—Stratigraphic ranges of the species of Lepicythara. 20. . L. toroensis: Shark Hole Point Formation (Early Pliocene), Province of Bocas del Toro, Panama L. turrita: Jackson Bluff Formation and Pinecrest beds (Pliocene), Florida L. aff. turrita: Nancy Point Formation (Late Mio- cene), Province of Bocas del Toro, Panama L. sp. A: Gatun Formation (Late Miocene), central Panama L. sp. B: Tuira Formation (Middle Miocene), Dar- ien, Panama L. sp. C: Nancy Point Formation (Late Miocene), Province of Bocas del Toro, Panama FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 9 7 Holocene / Recent 0.01 Pleistocene 1.9 24 _ late middle ie Pliocene early 5.1 |e late Wiles) ail middle 14.4 || Miocene early 10 species Jed ee dt Ld id | 24.6 Text-figure 3.—Species diversity of Lepicythara through time. The radiometric ages (in millions of years) on the left margin are taken from Bolli and Saunders (1985, p. 159, text-fig. 3). 21. L. sp. D: Late Miocene (?), Punta Judas, Pacific coast of Costa Rica 22. L. sp. E: Angostura Formation (Late Miocene), northwestern Ecuador ARE THERE NO LIVING SPECIES? Lepicythara ranges from late Early Miocene to Pleistocene. It seems strange that no living species has ever been recorded. In the Gibson-Smith collection of the NMB, there are two small, Recent specimens from two different localities, which are close to Lepicythara, but they cannot definitely be assigned to that genus. The larger specimen (restored height 6.2 mm, width 2.8 mm, ratio 2.21: Text-fig. 4) is well preserved. Its protoconch is not quite complete but has 2.5 volutions. There are a litthe more than four teleoconch whorls. This specimen (NMB H 18118) has been collected at NMB locality 17666: Adicora, east coast of the Para- guana Peninsula, Venezuela. The smaller specimen (re- stored height 4.9 mm, width 2.1 mm, ratio 2.33; Text- fig. 5) is not well preserved, and the number of vo- lutions of its protoconch cannot be determined. There are 3.25 teleoconch whorls. The specimen (NMB H 18119) has been collected at NMB locality 17671: Tu- cacas, Falcon, Venezuela. The two specimens probably do not represent the same species. The larger specimen has twelve axial ribs on its last whorl, the smaller only nine. On the other hand both show many characteristics including the spiral sculpture typical for Lepicythara. There is, however, one constant difference: the angulation of the profile of the teleoconch whorls continues to the last whorl, whereas in species of Lepicythara it is restricted to the early teleoconch whorls. SYSTEMATIC PALEONTOLOGY INTRODUCTION The organization and conventions of the systematic part are basically the same as those followed by Jung (1989, p. 35). In the following descriptions references to the size of a species is made by means of the words small, medium and large. These are defined as: “small”: height 10.5 mm or less; “*medium”’: height between 10.6 and 13.00 mm; “large”: height 13.1 mm or more. ABBREVIATIONS ANSP Academy of Natural Sciences, Philadelphia, PAS UWS] A CR Costa Rica DR Dominican Republic NMB Naturhistorisches Museum Basel, Switzer- land (the letter H after NMB stands for gas- tropods) PPP. Panama Paleontology Project PRI Paleontological Research Institution, Ithaca, INE UES AG UF Florida Museum of Natural History, Univer- sity of Florida, Gainesville, FL, U.S. A. USGS — United States Geological Survey USNM_ United States National Museum of Natural 10 BULLETIN 366 Text-figure 4.—Lepicythara? sp. 1. NMB H 181118. Recent specimen from NMB locality 17666: Adicora, east coast of the Paraguana Peninsula, Falcon, Venezuela. Height 6.2 mm, width 2.8 mm. 1, front view: 2, enlargement of apical area; 3, rear view: 4, enlargement of apical area; 5, apical view; 6, enlargement of apical view. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 11 3 x/0 4 x37 Text-figure 5.—Lepicythara? sp 2. NMB H 18119. Recent specimen from NMB locality 17671: Tucacas, Falc6n, Venezuela. Height 4.9 mm, width 2.1 mm. 1, front view; 2, rear view; 3, enlargement of apical area: 4, apical view. History, Smithsonian Institution, Washing- ton; DE) U.S: A: DIAGNOSTIC FEATURES The most important morphological characteristics of the species discussed in this paper are summarized in Table 2. They include the general habitus, the range of the restored heights, the number of volutions of the protoconch, the profiles of the early and late whorls, and the number of axial ribs on the body whorl on one hand and early whorls on the other hand. The species of Lepicythara can also be subdivided into groups of species based on the number of axial ribs per whorl. A first group with more or less the same number of axial ribs on early whorls and on the body whorl includes: L. basilissa, L. camaronensis, L. costaricensis, L. ct. heptagona, L. lopezana, L. cf. lo- pezana, L. paradisclusa, L. terminula, L. sp. A, L. sp. B, and L. sp. D. A second group of species having more axial ribs on the body whorl than on early whorls includes: L. cf. costaricensis, L. disclusa, L. heptagona, L. aff. hep- tagona, L. higensis, L. polygona, L. toroensis, L. sp. Cyandvixspye- A third group of species with more axial ribs on early whorls than on the body whorl includes only: L. turrita and L. aff. turrita. Family Turridae Adams and Adams, 1853 Genus LEPICYTHARA Olsson, 1964 Lepicythara Olsson 1964, p. 110. Type species (by original designation).—Cythara BULLETIN 366 Table 2.—Summary of the most important morphological characters discussed in the text. Range of Axial Axial (restored) ribs on — ribs on General height Volutions Profile Profile body early Species habitus (in mm) protoconch early whorls late whorls whorl whorls basilissa small slender 3.7-10.1 3.25 slightly convex slightly convex 7-8 7-9 camaronensts medium-large 12.4-19.7 3.0 straight ? slightly convex 8-9 8-9 biconic stout costaricensis medium-large moder- 9.5-16.1 2.5-2.75 straight angulated slightly convex 8-10 7-9 ately slender cf. costaricensis small biconic 10.5 254 straight angulated slightly convex 10 ) disclusa large, biconic moder- 13.1-16.9 2.75-3.0 straight angulated slightly convex 9-10 8-9 ately stout heptagona medium-large biconic, — 11.3—17.0 2.25 straight angulated slightly convex 8-9 7-8 moderately slender cf. heptagona small-large moderately —10.4—13.6 2.75-3.0 straight angulated slightly convex 8-9 8 slender aff. heptagona large moderately 13.7 3.25 straight angulated slightly convex g) 7 slender higensis medium-large 12.2-16.7 215) straight angulated slightly convex 10-11 7-9 slender lopezana medium-large moder- 11.5-14.0 P15) slightly convex convex 7-8 7-8 ately slender cf. lopezana small-medium 7.1-11.0 2S slightly convex convex 8-9 8 slender paradisclusa small-medium biconic 7.6-12.5 PTB) straight angulated straight 8-9 8-9 stout polygona small-medium 6.4-12.1 2.25—2.75 straight to slightly convex 12-28 8-13 slender convex terminula medium-large moder- 10.6—-19.4 2-5 straight angulated slightly convex 7-10 7-10 ately slender toroensis large biconic 19.3-19.6 29 straight angulated slightly convex 12-13 8-9 stout turrita small-large biconic, 8.9-14.9 2.75-—3.0 straight angulated convex 8-9 9-10 moderately stout aff. turrita large, moderately 14.8-17.7 Dl straight angulated slightly convex 7 8-9 slender sp. A medium slender 12.6—12.8 3:29) straight angulated slightly convex 8-9 7-8 sp. B large slender 14.0 Sat straight slightly convex 6-7 7 sp. C large, moderately Sys 25 straight angulated slightly convex 12 9 slender sp. D large stout 14.1 2 straight ? straight to 8 ? slightly convex spl medium slender 12.5 2, straight slightly convex 9 7] terminula Dall (1890, p. 38, pl. 2.5). Pliocene and Pleistocene of southern Florida. Diagnosis.—Shells of small to large size (total range of height: 10.1—19.7 mm), general shape ranging from stout to slender, protoconch with 2.25 to 3.25 volutions, about its first two volutions are smooth, the remainder sculptured by a varying number of opistho- cline to opisthocyrt axial riblets. Outer lip of proto- conch opisthocline to opisthocyrt. The number of te- leoconch whorls usually lies between 4.5 to 5.5, and in rare cases there are more than six whorls. Profile of early teleoconch whorls rarely slightly convex, usually straight and frequently with a carination or angulation near the abapical suture. Profile of late teleoconch whorls usually slightly convex, rarely convex, and even more rarely straight. Axial sculpture consists of a varying number per whorl of basically orthocline ribs, which may become somewhat sigmoid on the body whorl. Axial ribs usually narrow adapically and wider abapically. Spiral sculpture consists of narrow grooves or incised lines, which increase in number to- wards late whorls. Secondary spiral grooves are rare on early whorls, but more frequent on late whorls and the body whorl. All spiral grooves cross the sometimes fairly sharp ridges of the axial ribs. Suture not deep. Aperture narrow. Outer lip thickened. Sinus adjoining suture shallow to moderately deep. Inner surface of outer lip smooth, with or without a ridge parallel to FossiIL LEPICYTHARA IN TROPICAL AMERICA: JUNG 13 1 2 3 all x5 Text-figure 6.—Lepicythara basilissa (Gardner). USNM 351224. Holotype. USGS Station 3742. Shell Bluff, Shoal River, Walton County, Florida, Shoal River Formation. Height 9.8 mm, width 3.8 mm. 1, front view: 2, rear view; 3, from right side. the sharp edge of the outer lip. Columellar callus thin to moderately prominent. Parietal callus usually incon- spicuous, rarely thickened near sinus. Anterior canal straight or slightly twisted to the left, usually narrow, and short to moderately long. Remarks.—As now known the genus Lepicythara consists of 22 species, ten of which are not named or are identified by means of open nomenclature only. Its occurrence 1s restricted to tropical America and Florida and its total stratigraphic range is late Early Miocene to Pleistocene. Lepicythara basilissa (Gardner, 1937) Text-figures 6—9 “Cythara”™ basilissa Gardner, 1937, p. 344, pl. 42, f. 23-24. Description.—Of small size, slender. Protoconch consists of 3.25 volutions; surface of its first 2.5 vo- lutions smooth, the remainder sculptured by up to 15 opisthocyrt axial riblets. Number of teleoconch whorls up to 4.5, their profile slightly convex on early whorls as well as on late whorls. Teleoconch whorls sculp- tured by opisthocline to slightly sigmoid axial ribs; their number per whorl is seven to eight on early whorls and seven to nine on late whorls. Interspaces of axial ribs slightly concave, smooth except for sig- moid growth lines or weakly sculptured by incised spi- ral lines on the abapical part of the whorl. The crests of the axial ribs on spire whorls are crossed by a grad- ually increasing number of incised spiral lines. On the body whorl these incised spiral lines are present on the whole surface including the interspaces of the axial ribs but excluding a narrow zone on the interspaces, which adjoins the suture. Suture not deep. Aperature narrow. Outer lip thickened. Sinus adjoining suture rather shallow. Inner surface of outer lip smooth, with- out a ridge parallel to the sharp edge of the outer kip. Columellar and parietal calluses not conspicuous. An- terior canal straight, moderately long. 2 x80 Text-figure 7.—Lepicythara basilissa (Gardner). USNM 509803. USGS Station 23979: Shoal River, Walton County, Florida, Shoal River Formation. Height 5.8 mm, width 2.2 mm. 1, rear view; 2, enlargement of apical area; 3, apical view. 14 BULLETIN 366 (| SP 4 x90 Text-figure 8.—Lepicythara basilissa (Gardner). UF 102877. Shell Bluff, Shoal River, Walton County, Florida, Shoal River Formation. Height 6.0 mm, width 2.3 mm. 1, front view; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view. Holotype.—USNM 351224 (Text-fig. 6). Dimensions of holotype.—Height 9.8 mm, width 3.8 mm. Type locality—USGS Station 3742: Shell Bluff, Shoal River, Walton County, Florida. Shoal River For- mation (Middle Miocene). Remarks.—L. basilissa is a rare species as only 11 specimens from three different localities are available. Although the holotype—probably the only specimen Gardner (1937, p. 344) had at hand—has an incom- pletely preserved protoconch, Gardner stated that it must consist of more than three volutions. This state- ment now proves to be correct as shown by the single specimen with a complete protoconch consisting of 3.25 volutions (Text-fig. 9.5). Comparisons.—L. basilissa is the smallest of the species described in this report and cannot be com- pared meaningfully with any of them. It is more slen- FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 15 4 x50 5 x120 Text-figure 9.—Lepicythara basilissa (Gardner). UF 102878. Shell Bluff, Shoal River, Walton County, Florida, Shoal River Formation. Height 3.7 mm, width 1.7 m. 1, rear view: 2 ; 2, enlargement of apical area; 3, enlargement of body whorl; 4, apical view; 5, enlargement of apical view. 16 BULLETIN 366 Table 3.—Measurements (in mm) of Lepicythara basilissa (Gard- ner, 1937). Height/ Restored width Specimen height Width ratio USNM 351224 (holotype) 10.1 3.8 2.66 USGS locality 23979 5.8 Dr, 2.64 UF 66069 9.4 3.6 2.61 UF 88143 6.2 2.6 2.38 5.6 22 D9 UF 89592 6.0 2S 2.61 Shy/ 1.7 2.18 der, /.e., it has a smaller apical angle than other species. The only species with which Gardner (1937, p. 344) compared her L. basilissa is the living Mangilia (Cythara) cymella Dall (1886:101, pl. 12, f. 4). The present writer received the following material of M. cymella on loan from the USNM: two syntypes from Barbados (USNM 87419), one specimen from near Miami, Florida (USNM 410336), three specimens from off Ajax Reef, Florida (USNM 410348), and two specimens from the Campeche Bank off Yucatan, Mexico (USNM 667918). This material clearly shows that Mangilia cymella is not a species of Lepicythara but belongs to some other, possibly undescribed turrid genus. A few specimens of the available material of M. cymella show faint traces of spiral sculpture on late whorls, but all of the other specimens have no spiral sculpture. In this respect the original figure is mislead- ing. Another problem of the material of M. cymella con- cerns dimensions. In the original description Dall (1889, p. 102) indicated a maximum height of the shell of 12.5 mm. In the explanation of figure 4 on his Plate 12, Dall gave a height of 13.0 mm. None of the eight specimens cited above exceeds a height of 9 mm. It is therefore evident that a measuring error has occurred. Material.—Five lots with a total of eleven speci- mens as listed below: 1 spec., USNM 351224: holotype. USGS Station 3642: Shell Bluff, Shoal River, Walton County, Florida. Shoal River Formation (Middle Mio- cene). 1 spec., USGS locality 23979: Shoal River, Walton County, Florida (no additional details). Shoal River Formation (Middle Miocene). 1 spec., UF 66069: Shoal River Grotto (WLO04), Walton County, Florida. Shoal River Formation (Middle Miocene). 2 spec., UF 88143: Shoal River Grotto (WLO04), Walton County, Florida. Shoal River Formation (Middle Miocene). 1 3 Text-figure 10.—Lepicythara camaronensis Olsson. USNM 644221. Holotype. USGS Station 23480: Quebrada Camarones, Es- meraldas Province, Ecuador. Onzoloe Formation. Height 16.5 mm, width 7.7 mm. 1, front view; 2, rear view; 3, from right side. 6 spec., UF 89592: Shell Bluff (type locality) (WLO002), Walton County, Florida. Shoal River Formation (Middle Miocene). Measurements.—(see Table 3). Occurrence.—This species is recorded from the fol- lowing areas within Walton County, Florida (all Shoal River Formation): Shell Bluff, Shoal River: USGS 3742, UF 89592: Shoal River USGS 23979: Shoal River Grotto: UF 66069, UF 88143. Distribution.—Not known outside Walton County, Florida. Lepicythara camaronensis Olsson, 1964 Text-figures 10-13 Lepicythara camaronensis Olsson, 1964, p. 110, pl. 20, fig. 3, 3a. Description.—Oft medium to large size, biconic, rather stout. Protoconch consists of about three volu- tions. Apex hardly pointed. Number of teleoconch whorls up to five, their profile straight to slightly con- vex. Teleoconch whorls sculptured by eight to nine FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 17 1 3 Text-figure 11.—Lepicythara camaronensis Olsson. NMB H 18113. NMB locality 128222: km 493.050 of Trans Ecuadorian Pipeline System (TEPS), Esmeraldas Province, Ecuador, Onzole Formation. Height 14.0 mm, width 7.3 mm. 1, front view; 2, rear view; 3, from right side. orthocline to slightly opisthocline axial ribs per whorl. Axial ribs more or less alined on successive whorls. Interspaces of axial ribs slightly concave, sculptured by three to seven flat topped spiral riblets on spire whorls, which usually are subdivided centrally by an incised line. The spiral sculpture is crossing the axial ribs not only on the body whorl but also on the spire whorls. Suture not deep. Aperture moderately narrow. Outer lip thickened. Sinus adjoining suture moderately deep. Inner surface of outer lip smooth, but with a ridge parallel to the sharp edge of the outer lip ex- tending from the sinus to the beginning of the anterior canal. Columellar and parietal calluses moderately prominent. Anterior canal almost straight and short. Holotype.—USNM 644221 (Text-fig. 10). Height 16.5 mm, width Dimensions of holotype. 7.7 mm. Type locality.—UGSG locality 23480 Quebrada Ca- marones, Esmeraldas Province, Ecuador. Onzole For- mation (Early Pliocene) (Whittaker, 1988, fig. 2 and ja 1D). Remarks.—The protoconch of the holotype is not preserved, and the first 2.5 teleoconch whorls are pre- served as an internal mold. The figured paratype settlement of Camarones / / NMB 12826 = 19137 ( = PPP 3487 ) ¢ NMB 12825 = 19136 ( = PPP 3485 ) approx. 500 m Text-figure 12.—Sketch map of the lower course of the Rio Ca- marones, about 10 km east of the town of Esmeraldas, Ecuador, showing NMB localities that have yielded L. camaronensis. (USNM 645311) has a strongly worn protoconch that consists of about three volutions. The specimen is in- complete and has about four teleoconch whorls. Ols- son’s figure (1964, pl. 20, fig. 3a) is a misleading re- construction. All the other specimens at hand are not well preserved and partly fragmentary. Sculptural de- tails can hardly be recognized. The early teleoconch whorls are not preserved well enough to determine whether they are somewhat angulated near the periph- ery. Comparisons.—L. camaronensis may be compared with L. disclusa from the Early Pliocene Melajo Clay 18 BULLETIN 366 0 5 10 km ESMERALDAS Atacames Text-figure 13.—Sketch map of the Esmeraldas area showing NMB locality 12822, that has yielded L. camaronensis. Member of the Springvale Formation of Trinidad. L. camaronensis is somewhat stouter, its axial ribs are less prominent, and their number per whorl is higher in L. disclusa. Material.—Seven lots with a total of 18 specimens as listed below (see Text-figs. 12, 13): I spec., USNM 64421: holotype. USGS locality 23480: Quebrada Camerones, Esmeraldas Prov- ince, Ecuador. Onzole Formation (Early Plio- cene). I spec., USNM 645311: figured paratype. USGS lo- cality 23480: as above. 2 spec., NMB locality 12822: km 493.050 of Trans Ecuadorian Pipeline System (TEPS), Esmeraldas Province, Ecuador. Onzole Formation; Globoro- talia margaritae Zone (Early Pliocene). | spec., NMB locality 12825: Quebrada Camarones, about 10 km east of Esmeraldas, Ecuador. Onzole Formation; Globorotalia margaritae Zone (Early Pliocene). 2 spec., NMB locality 12826: Quebrada Camarones, as above. 4 spec., NMB locality 19136: Quebrada Camarones, as above. 5 spec., NMB locality 19137: Quebrada Camarones, as above. Measurements.—(see Table 4.) Occurrence.—This species is recorded from the fol- Table 4.—Measurements (in mm) of Lepicythara camaronensis Olsson, 1964. Height/ Restored width Specimen height Width ratio USNM 644221 (holotype) 16.9 TT 2.19 14.6 7.3 2.00 14.5 6.1 2.38 NMB locality 12826 19.7 = — 12.4 5.4 2.23 NMB locality 19136 16.9 6.7 BSD 16.1 6.9 2:38 NMB locality 19137 14.8 6.6 2.24 lowing NMB localities: 12822, 12825, 12826, 19136, 19137 (all Early Pliocene Onzole Formation, north- western Ecuador). Distribution.—So far this species is not known from outside northwestern Ecuador. Lepicythara costaricensis (Olsson, 1922) Text-figures 14-2] Cythara terminula costaricensis Olsson, 1922, p. 77, pl. 5, figs. 21, oy) Non Cythara terminula costaricensis Olsson. Woodring, 1970, p. 390. Description.—Oft medium to large size, biconic, moderately slender. Protoconch consists of 2.5 to 2.75 volutions. Surface of the first 1.5 volutions smooth, remainder of the protoconch sculptured by up to 22 opisthocyrt axial riblets. Apex not pointed or only slightly pointed. Number of teleoconch whorls up to all x5 Text-figure 14.—Lepicythara costaricensis (Olsson). PRI 20951. Lectotype. Hill la, Banana River, Limon Basin, Costa Rica. Rio Banano Formation. Height 12.3 mm, width 5.5 mm. 1, front view; 2, rear view; 3, from right side. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 19 all x5 Text-figure 15.—Lepicythara costaricensis (Olsson). PRI 42106. Paralectotype. Hill la. Banana River, Limon Basin, Costa Rica. Rio Banano Formation. Height 13.0 mm, width 5.7 mm. 1, front view: 2, rear view; 3, from right side. 5.25, their profile straight on early spire whorls, slight- ly convex on later spire whorls. The first two teleo- conch whorls are angulated near the adapical suture and thus overhanging it. Teleoconch whorls sculptured by orthocline to slightly opisthocline axial ribs. Their number per whorl is seven to nine on early whorls and eight to ten on the body whorl. The axial ribs are there- fore alined or not quite alined on successive whorls. They usually are narrow adapically and somewhat wider abapically. Interspaces of axial ribs concave, sculptured by four to six incised, spiral lines on spire whorls. On later spire whorls some secondary incised, spiral lines are introduced. All spiral lines cross the axial ribs. Suture not deep. Aperature moderately nar- row. Outer lip thickened. Sinus adjoining suture mod- erately deep. Inner surface of outer lip smooth, with or without a ridge parallel to the sharp edge of the other lip. If present, this ridge extends from the sinus to the beginning of the anterior canal. Columellar and parietal calluses thin. Anterior canal straight or slightly twisted to the left, narrow, and moderately long. Lectotype.—(selected herein) PRI 20951 (Text-fig. 14). Dimensions of lectotype.—Height 12.3 mm, width 5.5 mm. Type locality.—*Hill la, Banana River; Gatun Stage”. This indication probably refers to outcrops in the vicinity of La Bomba on Rio Banano, Limon Prov- ince, Costa Rica (see Jung, 1989, figs. 15-18). Rio Banano Formation (Pliocene). Remarks.—Brann and Kent (1960, p. 309) consid- Text-figure 16.—Lepicythara costaricensis (Olsson). NMB H 18148. NMB locality 18721 (=PPP 2224): northeast coast of Cayo Agua, Bocas del Toro, Panama. Cao Agua Formation. Height 14.4 mm, width 6.9 mm. |, front view; 2, rear view; 3, from right side. ered specimen PRI 20951 as the holotype of L. cos- taricensis citing both figures given by Olsson (Olsson, 1922, pl. 5, figs. 21-22). These two figures, however, represent two different specimens, which were united under PRI 20951. A lectotype selection becomes nec- essary, the lectotype being PRI 29051 (Text-fig. 14), and the paralectotype is renumbered PRI 42106 (Text- fig. 15). Olsson unfortunately gave the same height (13 mm) for both specimens, but they actually differ in height (see legend of the respective figures). As stated in the above description there are seven to nine axial ribs per whorl on early whorls and eight to ten on the body whorl. There is a remarkable exception: two specimens from Cayo Agua (NMB locality 18405) have more axial ribs per whorl: 9-10 on early whorls and 11 to 15 on the body whorl. Specimens of L. cos- taricensis from outside the Limon Basin of Costa Rica, i.e., from the Province of Bocas del Toro, Panama, seem to have a somewhat larger apical angle, and the axial ribs seem to be more regularly aligned on suc- cessive whorls (Text-fig. 16). There is, however, here is a variability in those two features as can be seen in the list of height/width ratio values. Comparisons.—L. costaricensis 1s similar to L. hep- tagona (Gabb). There is one constant difference, the 20 BULLETIN 366 < ’ : or a ce \ . bak : i ee >. 4 x90 Text-figure 17.—Lepicythara costaricensis (Olsson). NMB H 18140. NMB locality 17775 (=PPP 452): La Bomba, Rio Banano, Limon Province, Costa Rica. Rio Banano Formation. Height 7.7 mm, width 3.6 mm. 1, rear view; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view. protoconch of L. heptagona consists of 2.25 volutions, I spec., PRI 20951: lectotype figured by Olsson whereas that of L. costaricensis has 2.5 to 2.75. In (1922, pl. 5, p. 21); Hill la, Rio Banano, Limon addition, the number of axial ribs tends to be higher Province, CR; Rio Banano Formation (Pliocene). in L. costaricensis. I spec., PRI 42106: paralectotype figured by Ols- Material.—36 lots with a total of 139 specimens son (1922, pl. 5, p. 22); Hill la, Rio Banano, as listed below (for exact locations see Coates, Limon Province, CR; Rio Banano Formation 1999b-c). (Pliocene). Foss LEPICYTHARA IN TROPICAL AMERICA: JUNG a 3 x15 4 5 x 4 x80 Text-figure 18.—Lepicythara costaricensis (Olsson). NMB H 18141. NMB locality 17775 (=PPP 452): La Bomba, Rio Banano, Limon Province, Costa Rica. Rio Banano Formation. Height 12.0 mm, width 5.8 mm. 1, front view; 2, enlargement of apical view: 3, apical view: 4, enlargement of apical view. 10 spec., NMB locality 17445 (=PPP1726): La overlying NMB locality 17445. Type section of Bomba, Rio Banano, Limon Province, CR. Left Rio Banano Formation (Pliocene). Bank, 700 m southwest of railroad bridge. Type 4 spec., NMB locality 17447 (=PPP 1728): directly section of Rio Banano Formation (Pliocene). overlying NMB locality 17446. Type section of 9 spec., NMB locality 17446 (=PPP 1727): directly Rio Banano Formation (Pliocene). in) i) 1 x10 2 x60 Text-figure 19. BULLETIN Lepicythara costaricensis (Olsson). NMB H 18142. NMB locality 177772 (=PPP 449): Quitaria, Rio Banano, Limon Province, Costa Rica, Rio Banano Formation. Height 12.5 mm, width 5.6 mm. 1, oblique front view: 2, enlargement of apical view; 3, apical view. 13 spec., NMB locality 17451 (=PPP 1732): La Bomba, Rio Banano, Limon Province, CR. Right bank, about 500 m southwest of railroad bridge. Rio Banano Formation (Pliocene). 13. spec., NMB locality 17775 (=PPP 452): La Bomba, Rio Banano, Limon Province, CR. Right bank, 600 m southwest of railroad bridge. Rio Banano Formation (Pliocene). 6 spec., NMB locality 17783 (=PPP 460): La Bom- ba, Rio Banano, Limon Province, CR. Left bank, 700 m southwest of railroad bridge. Type section of Rio Banano Formation (Pliocene). 1 spec., NMB locality 18091 (=PPP 1983): La Bomba, Rio Banano, Limon Province, CR. Right bank, about 500 m southwest of railroad bridge. Rio Banano Formation (Pliocene). 14 spec., NMB locality 18095 (=PPP1984): La Bomba, Rio Banano, Limon Province, CR. Right i) to bank, about 500 m southwest of railroad bridge. Rio Banano Formation (Pliocene). spec., NMB locality 18099 (=PPP 686): La Bom- ba, Rio Banano, Limon Province, CR. Left bank, 700 m southwest of railroad bridge. Type section of Rio Banano Formation (Pliocene). spec., NMB locality 18100 (=PPP 1986): La Bomba, Rio Banano, Limon Province, CR. Left bank, 700 m southwest of railroad bridge. Type section of Rio Banano Formation (Pliocene). 4 spec., NMB locality 18101 (=PPP 691): La Bom- ba, Rio Banano, Limon Province, CR. Left bank, 700 m southwest of railroad bridge. Type section of Rio Banano Formation (Pliocene). spec., NMB locality 17454 (=PPP 1734): Quita- ria, Rio Banano, Limon Province, CR. Rio Ba- nano Formation (Pliocene). spec., NMB locality 17772 (=PPP 449): Quitaria, FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 23 5 x50 6 x100 Text-figure 20.—Lepicythara costaricensis (Olsson). NMB H 18149. NMB locality 18733 a(=PPP 2236): 1 km southeast of Punta de Tiburon, Cayo Agua, Bocas del Toro, Panama. Cayo Agua Formation. Height 11.1 mm, width 5.0 mm. 1, rear view: 2, enlargement of apical area; 3, further enlargement of apical area; 4, apical view; 5, enlargement of apical view; 6, further enlargement of apical view. 16 14 0 BULLETIN 366 [Ss 4 5 6 7 8 Text-figure 2].—(Restored) height/width diagram of L. costari- censis. | es) —_ Rio Banano, Limon Province, CR. Rio Banano Formation (Pliocene). spec., NMB locality 17773 (=PPP 450): Quitaria, Rio Banano, Limon Province, CR. Rio Banano Formation (Pliocene). | spec., NMB locality 18096 (=PPP 679): Quita- ria, Rio Banano, Limon Province, CR. Rio Ba- nano Formation (Pliocene). spec., NMB locality 18097 (=PPP 1985): Quita- ria, Rio Banano, Limon Province, CR. Rio Ba- nano Formation (Pliocene). spec., NMB locality 18270 (=PPP 1990): Rio Ba- nanito, road cut near Finca Banaga, Limon Prov- ince, CR. Rio Banano Formation (Pliocene). spec., NMB locality 18266 (=PPP 932): Rio Viz- ie) tO tO = bo caya, 3.5 km south-southwest of Quitaria, Limon Province, CR. Rio Banano Formation (Pliocene). spec., NMB locality 18267 (=PPP 933): Rio Viz- caya, about 3.5 km south-southeast of Quitaria, Limon Province, CR. Rio Banano Formation (Pli- ocene). spec., NMB locality 18268 (=PPP 935): Rio Viz- caya, 3.5 km south-southeast of Quitaria, Limon Province, CR. Rio Banano Formation (Pliocene). spec., NMB locality 17635 (=PPP 201): northeast coast of Cayo Agua, Bocas del Toro, Panama. Cayo Agua Formation (Pliocene). spec., NMB locality 17808 (=PPP 475): northeast coast of Cayo Agua, Bocas del Toro, Panama. Cayo Agua Formation (Pliocene). spec., NMB locality 17811 (=PPP 296): west of Punta de Tiburon, Cayo Agua, Bocas del Toro, Panama. Cayo Agua Formation (Pliocene). spec., NMB locality 17822 (=PPP 326): west of Punta de Nispero, Cayo Agua, Bocas del Toro, Panama. Cayo Agua Formation (Pliocene). spec., NMB locality 18374 (=PPP 1203): north- east coast of Cayo Agua, Bocas del Toro, Pana- ma. Cayo Agua Formation (Pliocene). spec., NMB locality 18405 (=PPP 67): south of Punta de Nispero, Cayo Agua, Bocas del Toro, Panama. Cayo Agua Formation (Pliocene). spec., NMB locality 18719 (=PPP 2222): north- east coast of Cayo Agua, Bocas del Toro, Pana- ma. Cayo Agua Formation (Pliocene). spec., NMB locality 18720 (=PPP 2223): 22 m south-southeast of Punta Norte, Cayo Agua. Bo- cas del Toro, Panama. Cayo Agua Formation (Pli- ocene). spec., NMB locality 18721 (=PPP 2224): north- east coast of Cayo Agua, Bocas del Toro, Pana- ma. Cayo Agua Formation (Pliocene). spec., NMB locality 18722 (=PPP 2225): north- east coast of Cayo Agua, Bocas del Toro, Pana- ma. Cayo Agua Formation (Pliocene). spec., NMB locality 18733 (=PPP 2236): 1 km southeast of Punta de Tiburon, Cayo Agua, Bocas del Toro, Panama. Cayo Agua Formation (Plio- cene). spec., NMB locality 17864 (=PPP 426): northeast coast of Isla Popa, Bocas del Toro, Panama. Cayo Agua Formation (Pliocene). spec., NMB locality 18602 (=PPP 423): northeast coast of Isla Popa, Bocas del Toro, Panama. Cayo Agua Formation (Pliocene). spec., NMB locality 18716 (=PPP 2217): Playa Lorenzo, 5 k southeast of Cayo Patterson, south coast of Valiente Peninsula. Bocas del Toro, Pan- ama. Shark Hole Point Formation (Pliocene). FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG DS Table 5——Measurements (in mm) of Lepicythara costaricensis (Olsson, 1922). Height/ Restored width Specimen height Width ratio PRI 20951: lectotype 12.4 S55) 225) PRI 42106: paralectotype 13.0 Sy/ 2.28 NMB locality 17445 14.4 6.5 Dgyp) 14.2 6.3 225 13.9 6.3 2.21 10.8 o22 2.08 NMB locality 17447 11.8 Sy) 2.27 NMB locality 17451 9.9 5.0 1.98 11.2 2.3 Zrii 13.4 -= — 9.5 4.8 1.98 NMB locality 17775 12.0 5.8 2.07 eA 5.8 2.19 NMB locality 17783 14.5 6.6 2.20 14.6 6.2 23'S) 11.6 She) 2.19 NMB locality 18095 12.0 Se PN 14.4 6.9 2.09 iil? Seif, 1.96 NMB locality 18099 12.3 6.2 1.98 NMB locality 18101 11.3 Sel 2.22 12.1 5.6 2.16 12.2 Ss) 2.22 1S? — — NMB locality 17454 14.7 6.8 2.16 NMB locality 17772 12.5 5.6 DDS, 13.6 ay) 2.30 NMB locality 17808 15.9 7.6 2.09 NMB locality 17811 11.4 5.4 praia i1t3} 5.0 2.26 NMB locality 17822 10.9 5.6 1295 9.9 5.0 1.98 11.5 6.0 1.92 NMB locality 18374 10.9 — -- 14.9 7.4 2.01 NMB locality 18405 12.1 6.0 2.02 16.1 7.8 2.06 NMB locality 18719 1229, 5.9 2.19. NMB locality 18720 13.0 6.6 1.97 NMB locality 18721 14.3 7.0 2.04 14.9 2s 2.07 12.5 6.7 1.87 13.9 6.8 2.04 NMB locality 18722 12.8 6.2 2.06 122 5.8 2.10 14.0 6.7 2.09 NMB locality 18733 ae S\-5) 2.04 NMB locality 17864 11.0 5) 2.00 122 5.6 2.18 NMB locality 18602 IORI Dall PP) NMB locality 18716 12.2 6.5 1.88 Measurements.—(See Table 5, Text-fig. 21.) Occurrence.—This species is recorded from the fol- lowing areas: Rio Banano, Rio Bananito, Rio Vizcaya, and Limon Province, Costa Rica. Rio Banano Formation (Pliocene): NMB localities: 17445-71447, 17451, IWASA Wide. ie ios Iis835 809M: 18095-18097, 18099-18101, 18266-18268, 18270. Cayo Agua, Bocas del Toro, Panama. Cayo Agua Formation (Pliocene): NMB localities: 17635, 17808, 17811, 17822, 18374, 18405, 18719— 18733. Isla Popas, Bocas del Toro, Panama. Cayo Agua Formation (Pliocene): NMB localities 17864, 18602. South coast of Valiente Peninsula, Bocas del Toro, Panama. Shark Hole Point Formation (Pliocene): NMB locality 18716. Distribution.—Rio Banano Formation (Pliocene), Limon Province, Costa Rica. Cayo Agua Formation (Pliocene), Cayo Agua and Isla Popa, Bocas del Toro, Panama. Shark Hole Point Formation (Pliocene), Va- liente Peninsula, Bocas del Toro, Panama. Lepicythara cf. costaricensis (Olsson, 1922) Text-figure 22 Remarks.—A single, not quite complete specimen from the Late Miocene Nancy Point Formation of NMB locality 18705 (=PPP 2206) is available. This locality is situated in the westernmost part of the south coast of the Valiente Peninsula, Province of Bocas del Toro, Panama (see Coates, 1999b, map 5, inset C, p. ZIIEM999 cy sections; yp» 322): The specimen is small (restored height 10.5 mm, width 4.8 mm, ratio 2.19) and does not have a per- fectly preserved protoconch, but is seen to consist of a little more than 2.5 volutions. The last part of the protoconch is sculptured by nine opisthocline to opis- thocyrt axial riblets. The number of preserved teleo- conch whorls is 4.5. The profile of the early teleoconch whorls is straight, that of the late teleoconch whorls slightly convex. The first two teleoconch whorls ar an- gulated near the adapical suture. The number of axial ribs per whorl is nine on early whorls and ten on the body whorl. The spiral sculpture is the same as that of L. costaricensis. The specimen of L. cf. costaricen- sis is smaller than L. costaricensis and seems to have more axial ribs per whorl. Lepicythara disclusa Jung, 1969 Text-figures 23-25 Lepicythara disclusa Jung, 1969, p. 551, pl. 59, figs. 7-10 (in part). Description.—Of large size, biconic, moderately stout. Protoconch consists of 2.75 to three volutions. A little less than the first two volutions are smooth, the remainder of the protoconch sculptured by 17 to 26 BULLETIN 366 5 x50 6 x100 Text-figure 22.—Lepicythara cf. costaricensis (Olsson). NMB H 181150. NMB locality 18705 (=PPP 2206): westernmost of the south coast of the Valiente Peninsula, Province of Bocas del Toro, Panama. Nancy Point Formation. Height 10.4 mm, width 4.7 mm. 1, view from right side; 2, enlargement of apical area; 3, further enlargement of apicalarea; 4, apical view; 5, enlargement of apical view; 6, further enlargement of apical view. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG Dy Text-figure 23.—Lepicythara disclusa Jung. NMB H 15291 Ho- lotype NMB locality 18574: Melajo River, soiuth slope of the east- ern part of the Northern Range, Trinidad. Melajo aClay Member of Springvale Formation. Height 16.0 mm, width 7.1 mm. 1, front view; 2, rear view; 3, from right side. 22 opisthocline to strongly opisthocyrt axial riblets. Apex a little pointed. Number of teleoconch whorls up to five, their profile straight on early teleoconch whorls and slightly convex on late whorls. The axial ribs of the first two teleoconch whorls are somewhat pointed at the periphery thus projecting a little over the ab- apical suture. Teleoconch whorls sculptured by eight to ten orthocline to slightly opisthocline axial ribs per whorl. The axial ribs may be alined on successive whorls and those on the body whorl may be somewhat sigmoid. Interspaces of axial ribs concave, sculptured by four incised, spiral lines on the first teleoconch whorl. Their number increases to twelve on the pen- ultimate whorl. There are few secondary incised, spiral lines. All spiral lines cross the axial ribs. Suture shal- low. Aperature narrow. Outer lip thickened. Sinus ad- joining suture moderately shallow. Inner surface of outer lip smooth, in rare cases with an inconspicuous ridge parallel to the slightly crenulated, sharp edge of the outer lip extending from the sinus to the beginning of the anterior canal. Columellar and parietal calluses weakly developed. Anterior canal straight, fairly long. Holotype.—NMB H 15291 (Text-fig. 23). Dimensions of holotype.—Height 16.0 mm, width 7.1 mm. Type locality.—NMB locality 18574 (=PJ 285): Melajo River on the south slope of the eastern part of the Northern Range, Trinidad (Jung, 1969, p. 296, text- fig. 2). Melajo Clay Member of Springvale Formation (Early Pliocene). Remarks.—When I originally described L. disclusa, the material from the Savaneta Glauconitic Sandstone Member of the Springvale Formation of the Central Range of Trinidad was erroneously included in it (Jung, 1969, p. 552). The material from the Central Range is quite a different species; it is considerably smaller, has a larger apical angle, and is described herein under the name of L. paradisclusa. The above description states that the spiral sculpture includes a few secondary incised lines. As a matter of fact, the number of these secondary lines is quite var- iable. On the penultimate whorl they are present but on the lower part of the body whorl, they are frequent- ly missing. Comparisons.—The differences between L. disclusa and L. paradisclusa have been mentioned briefly. L. toroensis is larger than L. disclusa and has a larger apical angle. Its protoconch consists of 2.5 volutions as compared to 2.75 to 3 in L. disclusa. L. disclusa has many more opisthocline to opisthocyrt axial. rib- lets on the late part of the protoconch. In addition the number of axial ribs in L. foroensis is eight to nine on early teleoconch whorls, but 12—13 on the body whorl. The corresponding figures in L. disclusa are also eight to nine on early whorls, but only 9-10 on the body whorl. The size of L. disclusa is similar to that of L. heptagona. The protoconch of L. heptagona has only 2.25 volutions, whereas that of L. disclusa has 2.75 to 3. In addition the number of axial ribs per whorl is smaller in L. heptagona on both the early teleoconch whorls and the body whorl. Material.—Eight lots with a total of 29 specimens as listed below. All the specimens come from the Me- lajo River, south slope of the Northern Range, north- eastern Trinidad, and have been collected fro the Me- lajo Clay Member of the Springvale Formation (Early Pliocene, Globorotalia margaritae Zone). (See Jung, 1969, p. 296, text-fig. 2.) 1 spec., NMB H 15291: holotype. NMB locality 18574 (=PJ 285). 1 spec., NMB H 15292: figured paratype. NMB lo- cality 18574 (=PJ 285). 28 BULLETIN 366 2 x70 3 xf0 Text-figure 24.—Lepicythara disclusa Jung. NMB H 18114. Paratype. NMB locality 18574: Melajo River, south slope of the eastern part of the Northern Range, Trinidad. Melajo Clay Member of Springvale Formation. Height 5.2 mm, width 2.6 m. 1, front view; 2, enlargement of apical area; 3, enlargement of apical view. I spec.,. NMB H 15293: figured paratype. NMB lo- cality 18574 (=PJ 285). 14 specs., NMB H 15290: paratypes. NMB locality 18574 (=PJ 285). 6 specs., NMB H 15286: paratypes. NMB locality 18923 (=Hutch 47). 2 specs., NMB H 15287: paratypes. NMB locality 18925 (=Hutch 51). 2 specs., NMB H 15288: paratypes. NMB locality 18571 (=KR 11862). 2 specs.,. NMB H 15289: paratypes. NMB locality 18922 (=RR 293). Measurements.—(See Table 6.) Occurrence.—This species occurs only along the Melajo River on the south slope of the Northern Range of northeastern Trinidad. It has been found at the fol- lowing NMB localities: 18571, 18574, 18922, 18923 and 18925. All these localities are part of the Melajo Clay Member of the Springvale Formation (Early Pli- ocene, Globorotalia margaritae Zone). Distribution.—So far L. disclusa is not known from outside Trinidad. Lepicythara heptagona (Gabb, 1873) Text-figures 26-31] Mangelia heptagona Gabb, 1873, p. 211. Cythara cercadica Maury, 1917, p. 61, pl. 9, fig. 15. Cythara heptagona (Gabb). Pilsbry, 1922, p. 322, pl. 17, fig. 9 (in part). Non Brown and Pilsbry, 1911, p. 345: see under L. sp. A. Non Weisbord, p. 55, pl. 5:13—14; see under L. cf. heptagona. Non Lepicythara heptagona (Gabb). Woodring, 1970, p. 390, pl. 60: 4, pl. 64:11; see under L. sp. A. Non Perrilliat, 1973, p. 57, pl. 28, figs. 9-12; see under L. aff. heptagona. Description.—Of medium to large size, biconic, rather slender to moderately stout. Protoconch consists of 2.25 volutions. Surface of protoconch smooth ex- cept for its last part which is sculptured by up to nine opisthocyrt axial riblets. Apex not pointed. Number of teleoconch whorls up to 5.5, their profile straight on early spire whorls, slightly convex on late spire whorls. The first two teleoconch whorls are somewhat FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 29 4 x70 Text-figure 25.—Lepicythara disclusa Jung. NMB H 18115. Paratype. NMB locality 18574: Melajo River, south slope of the eastern part of the Northern Range, Trinidad. Melajo Clay Member of Springvale Formation. Height 15.8 mm, width 6.6 mm. 1, spire whorls; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view. carinated near the abapical suture thus overhanging it a little. Early teleoconch whorls sculptured by seven, rarely eight practically orthocline axial ribs, late whorls usually by nine, sometimes by eight. On the body whorl the axial ribs may be somewhat sigmoid. On the spire whorls the axial ribs are narrow adapi- cally but wider abapically. Interspaces of axial ribs concave, sculptured by four to seven incised spiral lines on spire whorls. On late spire whorls secondary incised spiral lines are introduced. All spiral lines cross the axial ribs. Suture not deep. Aperature narrow. Out- er lip thickened. Sinus adjoining suture shallow to moderately deep. Inner surface of outer lip smooth, with a more or less well developed ridge parallel to the sharp edge of the outer lip extending from the sinus to the beginning of the anterior canal. Columellar and parietal calluses moderately prominent. Anterior canal straight to slightly twisted to the left, narrow and short. Dimensions of lectotype.-—(ot heptagona): Height 15.0 mm, width 6.5 mm. 30 BULLETIN 366 Table 6.—Measurements (in mm) of Lepicythara disclusa Jung, 1969. Height/ Restored width Specimen height Width ratio NMB H 15291 16.0 Tell 225, NMB H 15292 15.6 6.8 229 NMB H 15293 13.3 6.7 1.98 15.8 Iss 2.16 NMB H 15290 15.8 6.6 2.39 ISS 6.6 2.07 15.1 22 2.09 13.8 6.6 2.09 15.2 Tal 2.14 14.9 6.6 2.26 13.9 és 2.21 1 2 3 NMB H 15286 iS 7.4 2.05 15.3 7.4 2.07 all x5 13.6 6.5 2.09 NMB H 15287 13.2 69 1.91 Text-figure 27.—Lepicythara heptagona (Gabb). NMB H 18122. 13.1 = Sd NMB locality 16842. Rio Cana, Dominican Republic. Cercado For- NMB H 15288 15.2 AS 2 34 mation. Height 11.9 mm, width 5.0 mm. (Same specimen as Text- 15.0 70 a 414 fig. 30.) 1, front view; 2, rear view; 3, front right side. NMB H 15289 16.9 7.4 2.28 Type locality.—(of heptagona) According to Pilsbry (1922, p. 307) the exact locality and the age of the lectotype of L. heptagona are not known. For this rea- son the type locality is here restricted to NMB locality 16932, where 4 of the 16 known specimens have been 3 Text-figure 28.—Lepicythara heptagona (Gabb). NMB H 18123. Text-figure 26.—Lepicythara heptagona (Gabb). ANSP 2915 NMB locality 16914: Rio Mao, Dominican Republic. Cercado For- Lectotype. Cibao Region, Dominican Republic. Height 15.0 mm, mation. Height 15.6 mm, width 7.0 mm. 1, front view; 2, rear view; width 6.5 mm. 1, front view; 2, rear view; 3, from right side. 3, from right side. Fossit LEPICYTHARA IN TROPICAL AMERICA: JUNG 31 all x5 Text-figure 29.—Lepicythara heptagona (Gabb). PRI 28656. Ho- lotype of Cythara cercadica Maury. Rio Mao, Bluff 1 f Maury, Dominican Republic. Gurabo Formation. Height 14.6 mm, width 5.4 mm. 1, front view; 2, rear view: 3, from right side. collected: Rio Mao, Bluff 2 of Maury, Dominican Re- public. Cercado Formation (Late Miocene). For exact location see Saunders et al. (1986, text-figs. 29-31). Holotype.—(of cercadica) PRI 28656 (Text-fig. 29). Dimensions of holotype.—(of cercadica) Height 14.6 mm, width 5.4 mm. Type locality.—(of cercadica) Rio Mao, Bluff 1 of Maury, Dominican Republic. Gurabo Formation (Late Miocene). Remarks.—Pilsbry (1922, p. 322) mentioned the type (lectotype) and another specimen. This specimen is the only paralectotype (ANSP 79153). Its proto- conch is incomplete, but its last volution is sculptured by nine opisthocline to slightly opisthocyrt axial rib- lets. The number of its teleoconch whorls is 4.5; these are sculptured by seven axial ribs, which are alined on successive whorls. L. heptagona is not a common spe- cies at all. As interpreted here it occurs only in the Late Miocene of the Dominican Republic. Comparisons.—L. heptagona may be compared with L. costaricensis, but there are some clear differ- ences mentioned under the latter species. L. /opezana from the late Early to early Middle Miocene Baitoa Formation of the Dominican Republic has more pro- toconch volutions, is smaller than L. heptagona, and its parietal callus is more strongly developed. Material.—Ten lots (all from the Dominican Repub- lic) with a total of only 16 specimens as listed below: 1 spec., ANSP 2915 (lectotype), Ciboa Region. Ex- act locality and age not known. 1 spec., ANSP 79135 (paralectotype), Cibao Re- gion. Exact locality and age not known. 1 spec., PRI 28656 (holotype of Cythara cercadica Maury): Rio Mao, Bluff | of Maury. Gurabo For- mation (Late Miocene). | spec., NMB locality 15871: Rio Gurabo. Gurabo Formation (Late Miocene). 1 spec., NMB locality 16821: Rio Cana. Gurabo Formation (Latest Miocene). 1 spec., NMB locality 16842: Rio Cana. Cercado Formation (Late Miocene). 3 spec., NMB locality 16910: Rio Mao. Bluff 1 of Maury. Gurabo Formation (Late Miocene). 1 spec., NMB locality 16912: Rio Mao. Bluff 3 of Maury. Cercado Formation (Late Miocene). spec., NMB locality 16914: Rio Mao. Bluff 2 of Maury. Cercado Formation (Late Miocene). 4 spec., NMB locality 16832: Rio Mao. Bluff 2 of Maury. Cercado Formation (Late Miocene). i) Measurements.—(See Table 7.) Occurrences.—This species is recorded from the following sections in the Dominican Republic (for lo- cation see Saunders et al., 1986). Rio Gurabo: NMB locality 15871: Gurabo Formation (Late Miocene). Rio Cana: NMB localities 16821: Gurabo Formation (Lat- est Miocene) and 16842: Cercado Formation (Late Miocene). Rio Mao: NMB localities 16910: Gurabo Formation (Late Miocene) and 16912, 16914, and 16932: all Cercado Formation (Late Miocene). Distribution.—So far this species is not known from outside the Dominican Republic. Lepicythara cf. heptagona (Gabb, 1873) Text-figure 32 Remarks.—The two specimens from Colombia men- tioned by Woodring (1970, p. 391) under his Lepicyth- ara heptagona are at hand. They were collected from a horizon assigned by Woodring to the Middle Miocene (probably rather Late Miocene), about half a kilometer east of Usiacuri, northern Columbia (USGS Station 7873). The larger specimen (restored height 13. mm, width 6.5 mm, ratio 2.09) has a protoconch with a little less than three volutions carrying nine slightly opistho- cyrt axial riblets on its last portion. It has a little more than 4.5 teleoconch whorls carrying eight axial ribs per whorl on early whorls as well as on the body whorl. The profile of the teleoconch whorls is straight on the early whorls with an angulation near the abapical su- ture, but slightly convex on late whorls. The protoconch of the smaller specimen (restored height 10.4 mm, width 4.8 mm, ration 2.17) is not completely preserved, but carries ten opisthocyrt axial riblets on its last por- tion. The number of teleoconch whorls is 4.25. They Ww tN BULLETIN 3606 4 x70 Text-figure 30.—Lepicythara heptagona (Gabb). NMB H 18122. NMB locality 16842: Rio Cana, Dominican Republic. Cercado Formation. Height 11.9 mm, width 5.0 mm. (Same specimen as Text-fig. 27.) 1, front view of spire whorls; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view. are sculptured by eight axial ribs per whorl on early whorls, but by nine on the body whorl. The profile of the teleoconch whorls is the same as in the larger spec- imen. Both specimens from USGS Station 7873 are bi- conic and moderately slender. Their spiral sculpture consists of fine, incised lines which cross the axial ribs. Specimen PRI 22939 is the specimen described and figured by Weisbord (1929, p. 55, pl. 5, figs. 13-14) as Cythara heptagona? (Gabb), which was been collected from an unspecified locality and horizon in Colombia. It is re-figured here under this heading because it is only the third specimen of Lepicythara recorded from Colom- bia, 1f Oinomikado’s (1939, p. 624) undocumented rec- ord of Cythara cf. cercadica Maury from southwestern Colombia is not taken into consideration. The proto- conch of this weathered specimen is not preserved. The early teleoconch whorls carry seven axial ribs per whorl, the body whorl nine. Its anterior canal is broken. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 3 x20 4 x70 Oo es) Text-figure 31—Lepicythara heptagona (Gabb). NMB H 18124. NMB locality 16932: Rio Mao, Bluff 2 of Maury, Dominican Republic, Cercado Formation. Height 12.3 mm, width 4.5 mm. 1, spire whorls; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view. Due to its rather poor preservation the present writer is not able to determine whether specimen PRI 22939 is conspecific with the two specimens from USGS Sta- tion 7873. On the other hand he is confident that they do not belong to L. heptagona (Gabb). Their proto- conch has a little less than three volutions, whereas specimens of L. heptagona from the Dominican Re- public never have more than 2.25 volutions. Lepicythara aff. heptagona (Gabb, 1873) Text-figure 33 Lepicythara heptagona (Gabb). Perrilliat, 1973, p. 57, pl. 28, figs. 9-12. Remarks.—Under the name of L. heptagona Perri- lliat (1973, p. 57) recorded specimens from Santa Rosa, Veracruz, Mexico. The location of this locality 34 BULLETIN 366 Table 7.—Measurements (in mm) of Lepicythara heptagona (Gabb, 1873). Height/ Restored width Specimen height Width ratio ANSP 2915 15:2 6.5 2.34 ANSP 79153 ib 3} 5.0 2.26 PRI 28656 14.6 5.4 2.70 NMB locality 16821 13.2 Syi/ 2.32 NMB locality 16842 12.0 5.0 2.40 NMB locality 16910 14.9 TS) 1.99 14.2 6.8 2.09 NMB locality 16912 15:9) 6.9 2.30 NMB locality 16914 15.6 7.0 2.23 NMB locality 16932 14.6 6.4 2.29 17.0 7.0 2.43 is given by Perrilliat (1972, p. 11, fig. 1). Akers (1972, p. 30) assigned those beds to the Agueguexquite For- mation, which he dated as Middle to Late Pliocene. Later Akers (1979, p. 497) introduced the name ‘*Me- dias Aguas Formation” stating that it ““will be desig- nated in a subsequent report (Tulane Studies in Geol- ogy and Paleontology) for unnamed beds of upper Miocene age (Zone N17)”. This promised paper, how- ever, never appeared, and the Medias Aguas Formation is therefore a nomen nudum. For further discussion of the Santa Rosa beds reference is made to Vokes (1994, p. 138) and Vermeij and Vokes (1997, p. 84). Perrilliat had six specimens from the same locality (USGS 23737) at hand, when she described her L. hep- tagona. The present writer has seen five of them. The sixth specimen was not available; it has been figured by Perrilliat (1973, pl. 28, figs. 11-12) carrying the number IGM2415, and is deposited in the Instituto de Geologia of the Universidad Nacional Autonoma de Mexico. The dimensions given by Perrilliat show that this is a Lepicythara of large size like L. heptagona from the Dominican Republic. The number of axial ribs per whorl ranges from seven on early whorls to nine on late whorls like in L. heptagona from the Do- minican Republic. The specimen figured here (Text-fig. 33) has an in- complete protoconch, but its last part shows eleven opisthocline to slightly opisthocyrt axial riblets. The number of its teleoconch whorls is 4.25. The first te- leoconch whorl is sculptured by seven, later whorls by eight to nine axial ribs. Specimen USNM 647171 has been figured by Perrilliat (1973, pl. 28, figs. 9-10). Its protoconch is not quite complete, but it is seen to con- sist of probably 3.25 volutions. This is a clear differ- ence to the protoconch of L. heptagona from the Do- minican Republic, which consists of only 2.25 volu- tions. The material from Santa Rosa is therefore not identified as L. heptagona, and it is insufficient to 1 3 Text-figure 32.—Lepicythara cf. heptagona (Gabb). PRI 22939. Specimen from an unspecified locality and horizon in northern Co- lombia figured by Weisbord (1929, pl. 5:13—14) under the name of Cythara heptagona? (Gabb). Height 13.7 mm, width 6.8 mm. 1, front view; 2, rear view; 3, from right side. serve as type material for the formal description of a new species. Lepicythara higensis, new species Text-figures 34—36 Description.—Of medium to large size, slender. Protoconch consists of 2.5 volutions. The surface of a little less than the first two volutions is smooth. The remainder of the protoconch is sculptured by up to 14 opisthocline to opisthocyrt axial riblets. Apex not pointed. Number of teleoconch whorls up to 6.75; their profile straight on early spire whorls, slightly convex on late spire whorls. The first two to three teleoconch whorls are somewhat carinated near the abapical suture thus overhanging it a little. Early teleoconch whorls sculptured by seven to nine orthocline to slightly opis- thocline axial ribs, late whorls by ten to eleven. Inter- spaces of axial ribs concave, sculptured by three in- cised, spiral lines on early teleoconch whorls, by five on the penultimate whorl. There are a few secondary incised, spiral lines. All spiral lines cross the axial ribs. Suture shallow. Aperture narrow. Outer lip thickened. Sinus adjoining suture shallow. Inner surface of outer lip smooth, without a ridge parallel to the sharp edge of the outer lip, but with a small thickening just below the sinus adjoining the suture. Parietal callus slightly thickened near sinus, columellar callus inconspicuous. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 35 SmxXa5 4 x70 Text-figure 33.—Lepicythara aff. heptagona (Gabb). USNM 495825. USGS Station 23737: Santa Rosa, Veracruz, Mexico. Beds of Late Miocene age. Height 13.7 mm, width 6.0 mm. 1, from right side; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view. 36 BULLETIN 366 1 3 Text-figure 34.—Lepicythara higensis n. sp. NMB H 18146. Ho- lotype. NMB locality 17736: southern end of Golfo Dulce, Pacific side of Costa Rica: Quebrada El Higo, about 5 km northeat of Punta Banco; at bridge across Quebrada. Pleistocene. Height 16.1 mm, width 6.4 mm. 1, front view; 2, rear view; 3, from right side. Anterior canal twisted to the left, rather narrow, and moderately long. Holotype.—NMB H 18146 (Text-fig. 34). Dimensions of holotype.—Height 16.1 mm, width 6.4 mm. Type locality—NMB locality 17736 (=PPP 237): southern end of Golfo Dulce, Pacific side of Costa Rica. Quebrada El Higo, about 5 km northeast of Pun- ta Banco; at bridge across Quebrada. Pleistocene. See Text-figure 36. Remarks.—The largest lot of L. higensis consists of nine specimens, which are part of a float collection. The specimens are rolled and sculptural details are not preserved. With the exception of the protoconch most of them are complete specimens. The protoconch of the figured paratype is complete but a little weathered. Comparisons.—Specimens of L. polygona from the Cercado and Gurabo Formations (Late Miocene to Early Pliocene) of the Dominican Republic are smaller than L. higensis and have many more axial ribs per whorl. Specimens of L. toroensis trom the Early Pli- ocene Shark Hole Point Formation of the Valiente Pen- insula, Panama, have the same number of volutions of the protoconch, but L. toroensis is a larger and stouter species with more axial ribs per whorl. Material.—Five lots with a total of 15 specimens as listed below (all of the localities are situated in the Quebrada El Higo, about 5 km northeast of Punta Ban- co, southern end of Golfo Dulce, Pacific side of Costa Rica): (see Text-fig. 36). 1 spec., NMB locality 17736 (=PPP 237): at bridge across Quebrada El] Higo. Pleistocene. Holotype. 9 spec., NMB locality 17745 (=PPP 436): Quebrada El] Higo. Float collected over an air distance of 550 m, i.e., from near mouth of Quebrada to con- tact with basalt. Pleistocene. Paratypes. 1 spec., NMB locality 17746 (=PPP 273): Quebrada El Higo. Float collected over an air distance of 1.5 km above waterfall (basalt). Pleistocene. Pa- ratype. 3 spec., NMB locality 17752 (=PPP 262): Quebrada El Higo, about 550 m air distance downstream from contact with basalt. Pleistocene. Paratypes. 1 spec., NMB locality 17793 (=PPP 268): Quebrada El Higo, above waterfall. Pleistocene. Paratype. Measurements.—(See Table 8.) Occurrence.—This species is recorded from the fol- lowing NMB localities, which are all situated in the Quebrada El Higo, Pacific side of Costa Rica (Text- fig. 36): 17736, 17745, 17746, 17752, 17793 (Pleis- tocene). Distribution.—So far this species is not known out- side the type area. Etymology.—Reters to the geographic name of Que- brada El Higo, Province of Puntarenas, Costa Rica. Lepicythara lopezana, new species Text-figures 37—38 Description.—Of medium to large size, moderately slender. Protoconch consists of 2.75 volutions. The surface of the first two and a litthe more volutions is smooth, the remainder of the protoconch sculptured by up to eight opisthocline to opisthocyrt axial riblets. Apex slightly pointed. Number of teleoconch whorls up to 5.25; their profile is slightly convex on early whorls and convex on later whorls. Early teleoconch whorls sculptured by seven to eight orthocline to slightly opisthocline axial ribs, concave, sculptured by four incised spiral lines on the first teleoconch whorl and increasing in number to eight on the penultimate whorl There are a few secondary incised, spiral lines. All spiral lines cross the axial ribs. Suture moderately deep. Aperature narrow. Outer lip thickened. Sinus ad- joining suture rather deep. Inner surface of outer lip smooth, with a prominent ridge parallel to the sharp edge of the outer lip extending from the sinus to the beginning of the anterior canal. Parietal callus thick- ened near sinus, columellar callus moderately promi- FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 37 5 x50 6 x100 Text-figure 35.—Lepicythara higensis n. sp. NMB H 18147. Paratype. NMB locality 17752: Quebrada El Higo, about 5 km northeast of Punta BAnco, southern end of Golfo Dulce, Pacific side of Costa Rica, about 550 m air distance downstream from contact with basalt. Pleistocene. Height 14.6 mm, width 5.6 mm. 1, rear view; 2, enlargement of apical area; 3, further enlargement of apical area; 4, apical view; 5, enlargement of apical view; 6, further enlargement of apical view. 38 BULLETIN 366 PUNTARENAS Pta Banco Text-figure 36.—Sketch map of Quebrada El Higo, Costa Rica, showing position of NMB localitites that have yielded L. higensis. nent. Anterior canal slightly twisted to the left and short. Holotype.—NMB H 18126 (Text-fig. 37). Dimensions of holotype.—Height 13.9 mm, width 6.0 mm. Type locality.—NMB locality 17288: Lopez section on Rio Yaque del Norte, Dominican Republic. Baitoa Formation (Late Early to Early Middle Miocene). For location and stratigraphic position see Saunders ef al. (1986, text-fig. 21, 25, pl. 9). Remarks.—This species is based on six specimens only. The holotype and two paratypes from NMB lo- Table 8—Measurements (in mm) of Lepicythara higensis new species. Height/ Restored width Specimen height Width ratio NMB locality 17736 16.2 6.4 2.53 NMB locality 17745 16.7 6.0 2.78 13.9 5.4 2.57 13.2 5.0 2.64 13.0 5:3, 2.45 14.8 5.6 2.64 14.3 5.8 2.47 NMB locality 17746 122 4.8 2.54 NMB locality 17752 14.6 5.6 2.60 1333 2) 2.56 NMB locality 17793 12.9 5.3 2.43 cality 17289 are the only adult and more or less com- plete specimens. One of the paratypes is immature and the remaining two are fragmentary. However, one of the fragmentary paratypes has a complete protoconch (see Text-fig. 38.3). Comparisons.—L. lopezana is very similar to L. heptagona (Gabb) from the Cercado and Gurabo For- mations (Late Miocene) of the Dominican Republic. On an average L. heptagona is somewhat larger than L. lopezana. The main differences, however, is seen in the protoconch: that of L. heptagona has 2.25 volu- tions, that of L. lopezana 2.75. In addition the parietal callus of L. lopezana is more strongly developed. Material.—Four lots with a total of only six speci- all x5 Text-figure 37.—Lepicythara lopezana n. sp. NMB H 18126. Ho- lotype. NMB locality 17288: Lopez section on Rio Yaque del Norte, Dominican Republic. Baitoa Formation. Height 13.9 mm, width 6. mm. 1, front view; 2, rear view; 3, from right side. & FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 39 1 x70 3 x70 Text-figure 38.—Lepicythara lopezana n. sp. NMB H_ 18125. Paratype. NMB locality 17287. Lopez section on Rio Yaque del Norte, Dominican Republic. Baitoa Formation. Height 6.4 mm, width 3.0 mm. 1, enlargement of apical area; 2, apcal view; 3, en- largement of apical view. Table 9.—Measurements (in mm) of Lepicythara lopezana new species. Height/ Restored width Specimen height Width ratio NMB locality 17288 14.0 6.0 2.33, NMB locality 17289 12.4 Sf Dale) 11.5 5.0 2.30 mens are listed below. All the lots come from the Lo- pez section on Rio Yaque del Norte, Dominican Re- public. Baitoa Formation (late Early to early Middle Miocene): spec.. NMB locality 17286. Paratype. specs.. NMB locality 17287. Paratypes. spec., NMB locality 17288. Holotype. specs., NMB locality 17289 Paratypes. Ne Ne Measurements.—(See Table 9.) Occurrence.—This species occurs only in the Lopez section on Rio Yaque del Norte, Dominican Republic. It has been found at the following NMB localities: 17286-17289. All these localities are situated in the Baitoa Formation (late Early to early Middle Miocene) (Saunders er al., 1986, text-figs. 21, 25, pl. 9). Distribution.—So far L. lopezana is not known from outside the type area. Etymology.—Refers to the Lopez section on Rio Ya- que del Norte, Dominican Republic. Lepicythara cf. lopezana, new species Text-figure 39 Remarks.—At first the present writer was tempted to include in L. lopezana, five specimens from the Thomonde Formation of Haiti, which are of about the same age as L. lopezana from the Lopez section. Three of these specimens (USNM 482429) are from USGS locality 9945: trail from Hinche to Thomassique, at a crossing of Riviere Roche Salee, left bank, Departe- ment del l’Artibonite. The remaining two specimens (USNM 482596) are from USGS locality 9946, which is almost the same locality, but on the right bank of the river and stratigraphically 1 m above USGS local- ity 9945. The specimens from Haiti have a protoconch like that of L. lopezana consisting of 2.75 volutions. The figured protoconch (see Text-fig. 39.4) is not pre- served well enough to see this, but a specimen from USGS locality 9945 has a protoconch consisting of 2.75 volutions, but other features are incomplete. The Haitian specimens are smaller and a little more slender than those from the Lopez section, i.e., their apical angle is somewhat smaller. There are eight axial ribs per whorl on early teleoconch whorls, but eight to nine 40 BULLETIN 366 3 x20 Text-figure 39.—Lepicythara cf. lopezana n. sp. USNM 482596. USGS Station 9946: trail fro Hinche to Thomassique at crossing of Riviere Roche Salee, right bank, Department de I’ Artibonite, Haiti. Thomonde Formation. Height 11.0 mm, width 4.4 mm. 1, front view; 2, enlargement of apical area; 3, apical area; 4, enlargement of apical view. on the body whorl, which is slightly more than in L. Measurements.—(See Table 10.) lopezana. In addition the spiral sculpture of the Haitian ; specimens is not well developed. Because of these dif- Lepicythara paradisclusa, new species ferences and in view of the scarcity of material the Text-figures 40-42 specimens from Haiti are not considered conspecific “Cythara” (Brachicythara?) cf. terminula Dall. Rutsch, 1942, p. with L. lopezana. 169, pl. 3, figs. 10-11. FossitL LEPICYTHARA IN TROPICAL AMERICA: JUNG 4] Table 10.—Measurements (in mm) of Lepicythara cf. lopezana new species. Height/ Restored width Specimen height Width ratio USNM 482429 9.8 3\8) 2.51 Tal 3:2 222 USNM 482596 11.0 4.4 2.50 Lepicythara disclusa Jung, 1969, p. 551, in part (not pl. 59, figs. 7-10). Description.—Of small to medium size, strongly bi- conic and stout. Protoconch consists of 2.75 volutions. The surface of the first two volutions is smooth, the remainder of the protoconch is sculptured by about 12 opisthocline to opisthocyrt axial riblets. Apex hardly pointed. Number of teleoconch whorls 4.5, their profile practically straight. Teleoconch whorls sculptured by eight, rarely nine, orthocline to slightly opisthocline axial ribs per whorl thus being alined on successive whorls. The axial ribs of the first two teleoconch whorls are somewhat pointed at the periphery thus projecting a little over the abapical suture. Interspaces of axial ribs a little concave, sculptured by four in- cised, spiral lines on the first teleoconch whorl and increasing in number to ten on the penultimate whorl There are few secondary incised, spiral lines. All spiral lines cross the axial ribs. Suture shallow. Aperture nar- row. Outer lip thickened. Sinus adjoining suture shal- low. Inner surface of outer lip smooth, in rare cases with an inconspicuous ridge parallel to the sharp edge of the outer lip extending from the sinus to the begin- ning of the anterior canal. Columellar and parietal cal- luses weakly developed. Anterior canal slightly twisted to the left, rather short. Holotype.—NMB H 18120 (Text-fig. 40). Dimensions of holotype.—Height 8.6 mm, width 4.7 mm. Type locality.—NHB locality 13720: Central Range, Trinidad; 1700 feet southwest of Philippine Estate. Sa- vaneta Glauconitic Sandstone Member of Springvale Formation (Early Pliocene, Globorotalia margaritae Zone) (Jung, 1989, p. 13, fig. 13). Remarks.—Many of the available specimens are in- complete. There is not a single perfectly preserved protoconch. Comparisons.—L. paradisclusa cannot be compared with any of the species described herein. It is the only species with a straight profile on its late teleoconch whorls. In addition its apical angle is larger than in other species. all x5 Text-figure 40.—Lepicythara paradisclusa n. sp. NMB H 18120. Holotype. NMB locality 13720: 1700 feet southwest of Philippine Estate, Central Range, Trinidad. Savaneta Glauconitic Sandstone Member of Springvale Formation. Height 8.6 mm, width 4.7 mm. 1, front view; 2, rear view; 3, from right side. Material.—Five lots with a total of 26 specimens as listed below: 19 specs., NMB locality 13720 (holotype and para- types): 1700 feet southwest of Philippine Estate, Central Range, Trinidad. Savaneta Glauconitic Sandstone Member of Springvale Formation (Early Pliocene, Globorotalia margaritae Zone). 2 specs., NMB locality 10490 (paratypes): same lo- cality as lot 1. 1 spec., NMB H 6250 (paratype; figured by Rutsch, 1942, pl. 3, fig. 10) NMB locality 10515: Brechin Castle Estate, Central Range, Trinidad. Savaneta all x5 Text-figure 41.—Lepicythara paradisclusa n. sp. NMB H 18121. Paratype. NMB locality 13720: 1700 feet southwest of Philippine Estate, Central Range, Trinidad. Savaneta Glauconitic Sandstone Member of Springvale Formation. Height 8.1 mm, width 4.3 mm 1, front view; 2, rear view; 3, from right side. 42 BULLETIN 366 Text-figure 42.—Lepicythara paradisclusa n. sp. NMB H 18116. Paratype. NMB locality 13720: 1700 feet southwest of Philippine Estate, Central Range, Trinidad, Savaneta Glauconitic Sandstone Member of Springvale Formation. Height 6.4 mm, width 3.3 mm. 1, rear view; 2, enlargement of apica area; 3, apical area; 4, enlargement of apical view. Glauconitic Sandstone Member of Springvale Formation (Early Pliocene, G. margaritae Zone). | spec., NMB H 6251 (paratype; figured by Rutsch, 1942, pl. 3, fig. 11). NMB locality 10515: same as lot 3. 3 spec., NMB H 6288 (paratypes; mentioned by Rutsch, 1942, p. 170). NMB locality 10512: Rio Dulce, Central Range, Trinidad. Gransaull Clay 4 x70 5 Member of Springvale Formation (Early Plio- cene, G. margaritae Zone). Measurements.—(See Table 11.) Occurrences.—This species is recorded from the following NMB localities, which are all situated in the Early Pliocene Springvale Formation of the Central Range of Trinidad: 10490, 10512, 10515, 13720. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 43 Table 11.—Measurements (in mm) of Lepicythara paradisclusa new species. Height/ Restored width Specimen height Width ratio NMB locality 13720 8.6 4.7 1.82 8.2 4.3 1.91 12.5 5.8 2.16 OF 4.9 1.98 7.6 4.1 1.85 Oy} 5.0 1.86 10.1 4.8 2.10 11.0 52 2.12 9.0 4.6 1.96 NMB H 6250 10.5 4.9 2.14 NMB H 6251 12.3 6.2 1.98 HMB H 6288 10.5 5.6 1.87 Distribution.—So far this species is not known from outside the Central Range of Trinidad. Etymology.—Greek para (= next to, beside); refer- ring to the fact that geographically and stratigraphi- cally this species is close to L. disclusa. Lepicythara polygona (Gabb, 1873) Text-figures 43-56 Mangelia polygona Gabb, 1873, p. 211. Cythara polygona (Gabb). Pilsbry, 1922, p. 322, pl. 17, fig. 10. Cythara polygona Gabb. Maury, 1917, p. 60, pl. 9, fig. 13. Cythara caimitica Maury, 1917, p. 60, pl. 9, fig. 14. Description.—Of small to medium size, slender to moderately slender. Protoconch consists of 2.25 to 2.75 volutions. Surface of protoconch smooth except for its last part, which is sculptured by up to 20 axial all x5 Text-figure 44.—Lepicythara polygona (Gabb). PRI 28654. Spec- imen figured by Maury (1917, pl. 9, p. 130). Rio Mao, Bluff 3 of Maury, Dominican Republic. Cercado Formation. Height 10.7 mm, width 4.6 mm. 1, front view; 2, rear view; 3, from right side. riblets. The first riblets are faint, but gradually become more conspicuous. At the same time their shape is changing from opisthocyrt in the beginning to opistho- cline toward the end of the protoconch. In the inter- spaces of the last axial riblets there are four (rarely five) equally spaced flat, spiral ridges, which do not cross the axial riblets. Apex not pointed. Number of teleoconch whorls up to five, their profile almost straight to convex on early spire whorls, slightly con- vex on late spire whorls. The first one to two teleo- conch whorls may be somewhat carinated near the ab- 1 2 3 all x5 Text-figure 43.—Lepicythara polygona (Gabb). ANSP 2916. Lec- totype. Cibao Region, Dominican Republic. Exact locality and age unknown. Height 10.9 mm, width 4.6 mm. 1, front view; 2, rear view; 3, from right side. all x5 Text-figure 45.—Lepicythara polygona (Gabb). PRI 28655. Ho- lotype of Cythara caimitica Maury (1917, p. 60, pl. 7, fig. 14). Rio Cana near Caimito, Dominican Republic. Cercado Formation. Height 9.8 mm, width 4.9 mm. 1, front view; 2, rear view; 3, from right side. 44 BULLETIN 366 Text-figure 46.—Lepicythara polygona (Gabb). ANSP 79154. Paralectotype (with 13 axial ribs on body whorl). Cibao Region, Dominican Republic. Exact locality and age unknown. Height 5.8 mm, width 2.7 mm. 1, from right side; 2, enlargement of apical area; 3, enlargement of apical view. apical suture. Early teleoconch whorls sculptured by eight to thirteen practically orthocline axial ribs, late whorls by 12 to 28. On the body whorl the axial ribs may be slightly sigmoid. On the spire whorls the axial ribs have practically the same width from suture to suture. Interspaces of axial ribs concave. On the first teleoconch whorl these interspaces are sculptured by five or six spiral threads with interspaces of varying width. On later whorls these spiral threads become flat- topped and their interspaces narrower. On late whorls these flat-topped and wide spirals may be subdivided by a median, incised line. All spiral threads of the teleoconch cross the axial ribs. Suture not deep. Ap- erture narrow. Outer lip thickened. Sinus adjoining su- ture shallow to moderately deep. Inner surface of outer lip smooth, with a more or less well-developed ridge parallel to the sharp edge of the outer lip. This ridge extends from the sinus to the beginning of the anterior canal or only part of this distance. Columellar and pa- rietal calluses moderately prominent. Anterior canal slightly twisted to the left, narrow, and short. Lectotype.—(of polygona) ANSP 2916 (Text-fig. 43). Dimensions of lectotype.—(of polygona) Height 10.9 mm, width 4.6 mm. Type locality.—(ot polygona) According to Pilsbry (1922, p. 307), the exact locality and age of the lec- totype of L. polygona are not known. For this reason the type locality is here restricted to NMB locality 16923 (from where 83 specimens are available): Rio Mao, mouth of Arroyo Bajon, Dominican Republic. Cercado Formation (Late Miocene). For exact location and stratigraphic position, see Saunders ef al. (1986, text-figs. 29-30, 32). Holotype.—(of caimitica) PRI 28655 (Text-fig. 45). Dimensions of holotype.—(of caimitica) Height 9.8 mm, width 4.9 mm. Type locality.—(of caimitica) Rio Cana near Cai- mito, Dominican Republic. Cercado Formation (Late Miocene). Remarks.—L. polygona 1s represented by a total of 1184 specimens from 40 different localities from the sections of Rio Mao, Rio Cana, and Rio Gurabo. The provenance of the material is not even: there are 526 specimens from 18 localities along Rio Mao, 23 spec- FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 45 Text-figure 47. w ie > > Lepicythara polygona (Gabb). ANSP 79514. Paralectotype (with 17 axial ribs on body whorl). Cibao Region, Dominican Republic. Exact locality and age unknown. Height 7.0 mm, width 3.4 mm. 1, from left side: 2, enlargement of apical area; 3, enlargement of apical view. imens from nine localities along Rio Cana, and 635 specimens from 13 localities along Rio Gurabo. It is not surprising that this large amount of material shows some variability in several respects. As indi- cated in the description the number of axial ribs on teleoconch whorls varies greatly but differently from river to river. The number of axial ribs on early teleo- conch whorls varies from ten to thirteen on Rio Mao, from eight to eleven on Rio Cana, and from ten to thirteen again on Rio Gurabo. The corresponding num- ber on the body whorl varies from 14 to 23 on Rio Mao, from 12 to 18 on Rio Cana, and from 13 to 28 on Rio Gurabo. The protoconch is said to vary from 2.25 to 2.75 volutions in the above description. As a matter of fact, it varies from 2.5 to 2.74 volutions in the material from Rio Mao, but from 2.25 to 2.5 in the material from Rio Cana and Rio Gurabo. In addition the initial vo- lution in the material from Rio Mao is very slightly smaller than that in the material from Rio Cana and Rio Gurabo. Whether this has to be interpreted as a geographic variation remains undetermined for the time being. Stratigraphically, the material from Rio Mao occurs between Bluff 2 and 3 of Maury, which corresponds to about 45 m of section within the Cer- cado Formation. In Rio Cana, L. polygona occurs from 170 to 230 m in the section, i.e., over a thickness of 60 m in the upper part of the Cercado Formation, and in the Rio Gurabo from 80 to 140 m in the section, i.e., also over a thickness of 60 m in the upper part of the Cercado Formation. Thus, L. polygona lived at about the same time in all three river sections. There is one stratigraphic exception in the Rio Cana section: NMB locality 16817 has yielded a single specimen of L. polygona, which belongs to the Early Pliocene part of the Gurabo Formation (stratigraphic distribution ac- cording to Saunders et al., 1986). As listed under material, there are nine paralecto- types of L. polygona (ANSP 79154). Three of them are figured (see Text-fig. 46). Two of them have a pro- toconch with 2.5 volutions, the third with 2.75 volu- tions. The surface of the first two volutions is smooth. The remainder of the protoconch is sculptured by about twelve axial riblets. The first of these riblets are faint, but gradually become more conspicuous. At the same time, their shape is changing from opisthocyrt in the beginning to opisthocline toward the end of the protoconch. In the interspaces of the last few axial 46 BULLETIN 366 2 x70 Text-figure 48.—Lepicythara polygona (Gabb). ANSP 79154. Paralectotype (with 19 axial ribs on body whorl) Cibao Region. Dominican Republic. Exact locality and age unknown. Height 9.7 mm, width 4.0 mm. 1, front view; 2, enlargement of apical area; 3, enlargement of apical view. riblets, there are four equally spaced spiral threads, which however, do not cross the axial riblets. Further- more, their initial volution is slightly smaller than that of protoconchs from the sections of Rio Cana and Rio Gurabo (see above). Comparison with a protoconch from NMB locality 16915 on Rio Mao (Text-fig. 50.4) shows that they are practically identical These features make it highly probable that the type lot of L. poly- gona had been collected from the Rio Mao section. Comparisons.—L. polygona cannot meaningfully be compared with any of the species described herein. It has many more axial ribs on the teleoconch whorls than any other species. Material.—The NMB localities cited are all from the Late Miocene Cercado Formation of the Domini- can Republic except as noted (NMB locality 16817: Rio Cana, Early Pliocene part of Gurabo Formation, and NMB locality 15878: Rio Gurabo, Late Miocene part of Gurabo Formation). There are 40 lots with a total of 1184 specimens as listed below: 1 spec., ANSP 2916 (lectotype): Cibao Region. Ex- act locality and age unknown. 9 spec., ANSP 79154 (paralectotypes): Cibao Re- gion. Exact locality and age unknown. 1 spec., PRI 28654 (figured by Maury 1917, pl. 9, fig. 13): Rio Mao, Bluff 3 of Maury. 1 spec., PRI 28655: holotype of L. caimitica; Rio Cana near Caimito. 18 spec., NMB locality 16912: Rio Mao, Bluff 3 of Maury. 79 spec., NMB 16913: Rio Mao, Bluff 3 of Maury. 1 spec.. NMB 16914: Rio Mao, Bluff 2 of Maury. 37 spec., NMB 16915: Rio Mao, Arroyo Bajon. 7 spec., NMB 16917: Rio Mao, Arroyo Bajon. 32 spec., NMB 16917: Rio Mao, Arroyo Bajon. 42 spec., NMB 16918: Rio Mao, Arroyo Bajon. Il spec., NMB 16922: Rio Mao, Arroyo Bajon. 83 spec., NMB 16923: Rio Mao, Arroyo Bajon. 42 spec., NMB 16924: Rio Mao, Arroyo Bajon. 74 spec., NMB 16926: Rio Mao, Arroyo Bajon. 63 spec., NMB 16927: Rio Mao, Arroyo Bajon. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 47 tof 7 x/0 Text-figure 49.—Lepicythara polygona (Gabb). NMB locality 16913: Rio Mao, Bluff 3 of Maury, Dominican Republic, Cercado Formation. 1-2, NMB H 18127. Height 9.9 mm, width 3.6 mm. 1, front view of aperture; 2, enlargement of apical area. 3-4, NMB H 18128. Height 8.6 with a ridge parallel to the sharp edge of the outer lip; 4, mm, width 3.6 mm. 3, front view of aperature: note inner surface of outer lip ght 6.5 mm, width 2.7 mm. 5, rear view: 6, enlargement of apical area; 7, further enlargement enlargement of apical area. 5-7, NMB 18129. Hei of apical area. 48 BULLETIN 366 4 x70 Text-figure SO.—Lepicythara polygona (Gabb). NMB H 18139. NMB locality 16915: Rio Mao, Arroyo Bajon, Dominican Republic. Cercado Formation. Height 10.6 mm, width 4.4 mm. 1, front view of spire whorls; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view. n 20 spec., NMB 16928: Rio Mao, Arroyo Bajon. 4 spec., NMB 16929: Rio Mao, 130 m below Ar- royo Bajon. spec., NMB 16855: Rio Cana. spec., NMB 16856: Rio Cana. spec., NMB 16986: Rio Cana. Wn Wn 2 spec., NMB 17269: Rio Mao, Bluff 3 of Maury. 3 spec., NMB 17003: Rio Cana. | spec., NMB 16817: Rio Cana, Canada de Zamba. 8 spec., NMB 15878: Rio Gurabo. Gurabo Forma- Gurabo Formation (Early Pliocene). tion (Late Miocene). 5 spec., NMB 16838: Rio Cana. 14 spec., NMB 15900: Rio Gurabo. 1 spec., NMB 16844: Rio Cana. 180 spec., NMB 15903: Rio Gurabo. | spec., NMB 16854: Rio Cana. 78 spec., NMB 15904: Rio Gurabo. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 49 4 x60 Text-figure 51.—Lepicythara polygona (Gabb). 1-2, NMB H 18130. NMB locality 16844. Rio Cana, Dominican Republic. Cercado For- mation. Height 9.0 mm, width 4.3 mm. 1, rear view; 2, enlargement of apical area. 3-5, NMB H 18131. NMB locality 16844. Rio Cana, Dominican Republic. Cercado Formation. Height 9.0 mm, width 4.3 mm. 3, rear view; 4, enlargement of apica area; 5, enlargement to show oPxs0 spiral sculpture. 113 spec., NMB 15906: Rio Gurabo. 15 spec., NMB 15914: Rio Gurabo. 65 spec., NMB 15907: Rio Gurabo. 27 spec., NMB 15915: Rio Gurabo. 55 spec., NMB 15910: Rio Gurabo. 14 spec., NMB 15916: Rio Gurabo. 32 spec., NMB 15911: Rio Gurabo. 31 spec., NMB 15912: Rio Gurabo. 3 spec., NMB 15913: Rio Gurabo. Measurements.—(See Table 12 and Text-figure 56.) Occurrence.—This species is recorded from the fol- 50 BULLETIN 366 6 x40 7 x90 Text-figure 52.—Lepicythara polygona (Gabb). 1-4, NMB H 18137. NMB locality 16856: Rio Cana, Dominican Republic. Cercado For- mation. Height 9.5 mm, width 4.0 mm. 1, rear view; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view. 5-7, NMB H 18138. NMB locality 17003: Rio Cana, Dominican Republic. Cercado Formation. Height 5.2 mm, width 2.6 mm. 5, enlargement of apiclarea; 6, apical view; 7, enlargement of apical view. FosstL LEPICYTHARA IN TROPICAL AMERICA: JUNG 51 Text-figure 53.—Lepicythara polygona (Gabb). NMB locality 15906: Rio Gurabo, Dominican Republic, Cercado Formation. 1-3, NMB H 18132. Height 8.6 mm, width 3.33 mm. 1, rear view: 2, enalrgement of apical area; 3, enlargement to show spiral sculpture. 4-6, NMB H 18133. Height 10.2 mm, width 4.9 mm. 4, rear view: 5, enlargement of apical area; 6, enlargement to show spiral sculpture. Nn i) 6} 5.4l(0) BULLETIN 366 Text-figure 54.—Lepicythara polygona (Gabb). NMB locality 15906: Rio Gurabo, Dominican Republic, Cercado Formation. 1-2, NMB H 18134. Height 11.4 mm, width 4.4 mm. 1, front view; 2, enlargement of apical area. 3-4, NMB H 18135. Height 10.0 mm, width 4.1 mm. 3, front view: 4, enlargement of apical area. lowing NMB localities and section in the Dominican Republic: Rio Mao: 16912-16918, 16922-16924, 16926— 16929, 17269: all Cercado Formation (Late Mio- cene). Rio Cana: 16838, 16844, 16854-16856, 16986, 17003: all Cercado Formation (Late Miocene); 16817: Gurabo Formation (Early Pliocene). Rio Gurabo: 15900, 15903, 15904, 15906, 15907, 15910-15916: all Cercado Formation (Late Mio- cene); 15878: Gurabo Formation (Late Miocene). Distribution.—So far this species is not known from outside the Dominican Republic. Lepicythara terminula (Dall, 1890) Text-figures 57—64 Mangilia (Cythara) terminula Dall, 1890, p. 38, pl. 2, fig. 5. Lepicythara terminula Dall. Olsson, 1964, p. 111. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 53 Text-figure 55.—Lepicythara polygona (Gabb). NMB H 18136. NMB locality 15903: Rio Gurabo, Dominican Republic, Cercado Formation Height 6.1 mm, width 2.8 mm. 1, oblique front view; 2, enlargement of apical area; 3, apical area; 4, enlargement of apical view. Description.—Of medium to large size, biconic, moderately slender. Protoconch consists of 2.5 volu- tions. The surface of the first one and a half volutions is smooth, the remainder of the protoconch sculptured by up to 17 slightly opisthocline axial riblets. Apex not pointed. Number of teleoconch whorls up to 5.75, their profile straight on early spire whorls, slightly convex on later spire whorls. The first two teleoconch whorls are somewhat carinated near the abapical suture and thus overhanging it. Teleoconch whorls sculptured by orthocline to slightly opisthocline axial ribs. Their number per whorl is usually eight or nine, rarely sev- en, or up to ten. The axial ribs may or may not be alined on successive whorls. They are narrow adapi- cally and wider abapically. Interspaces of axial ribs concave, sculptured by three to seven incised, spiral lines on spire whorls. On later spire whorls some sec- ondary incised, spiral lines are introduced. All spiral lines cross the axial ribs. Suture not deep. Aperture narrow. Outer lip thickened. Sinus adjoining suture 54 BULLETIN 366 e 12 5 e ee 11 10 9 1 2 3 all x5 g Text-figure 57.—Lepicythara terminula (Dall). USNM 97338. Lectotype. Caloosahatchee River, Florida. Caloosahatchee Forma- tion. Height 14.4 mm, width 6.2 mm. 1, front view; 2, rear view; 3, from right side. ul ee ee e 6 e 5 le 7 a as ea Sa 0 2 3 4 5 Text-figure 56.—(Restored) height/width diagram of L. polygona. moderately deep. Inner surface of outer lip smooth, with a slight indication of a ridge parallel to the sharp edge of the outer lip extending from the sinus to the beginning of the anterior canal Columellar and parietal Table 12.—Measurements (in mm) of Lepicythara polygona (Gabb, 1873). 1 3 Height/ Restored width all x5 Specimen height Width ratio PRI 28654 10.7 ae 232 Text-figure 58.—Lepicythara terminula (Dall). USNM oes ANSP 2916 113 aG 7 46 Paralectotype. Caloosahatchee River, Florida. Caloosahatchee For- a a ie d ES ati eight 15 leh iew; 2, rear view; ANSP 79154 91 36 253 mation. Height 15.7 mm, width 6.6 mm. 1, front view; 2, rear view 3, from right side. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG Nn Nn 1 3 Text-figure 59 —Lepicythara terminula (Dall). USNM 495823 (ex 163902). USGS Station 3300. Shell Creek, De Soto County, Florida. Caloosahatchee Formation. Height 16.4 mm, width 7.0 mm. 1, front view; 2, rear view: 3, from right side. calluses thin. Anterior canal straight or slightly twisted to the left, narrow, and moderately long. Lectotype.—(selected herein) USNM 97338 (Text- ine, Ss Dimensions of lectotype.—Height 14.4 mm, width 6.2 mm. Type locality.—Caloosahatchee River, Florida. Ca- loosahatchee Formation (Plio-Pleistocene). Remarks.—Dall (1890, p. 38) apparently had two specimens available when he described L. terminula. He commented that the species is rare. On the label accompanying specimen USNM 97338 it says “‘fig- ured syntype’’, which is here selected as the lectotype. The label of specimen USNM 647034 says ““measured syntype’’. This specimen is the paralectotype (Text-fig. 58). The present writer was first confused about the identity of these specimens until he found out that Dall had given the (approximate) measurements of the un- figured paralectotype in the original description but not those of the lectotype. Whenever preserved, the protoconch of this species consists of 2.5 volutions and therefore represents a constant feature. The last volution of the protoconch is sculptured by slightly opisthocline axial riblets. The 1 3 Text-figure 60.—Lepicythara terminula (Dall). NMB H 18117. NMB locality 18960: Shell Pit south of Arcadia, De Soto County, Florida. Caloosahatchee Formation. Height 16.6 mm, width 7.2 mm. 1, front view; 2, rear view; 3, from right side. number of 17 such riblets given in the above descrip- tion is rarely observable due to imperfect preservation. On the other hand, the number of axial ribs per teleo- conch whorl is somewhat variable with the result that these axial ribs may be alined on successive whorls or not. Comparisons.—L. toroensis from the Early Pliocene Shark Hole Point Formation of the Valiente Peninsula of Panama is also a large species. L. toroensis and L. terminula both have 2.5 protoconch volutions. L. to- roensis has a larger apical angle, /.e., it is less slender than L. terminula. In addition, L. toroensis has more axial ribs on the body whorl than on early whorls, whereas L. terminula belongs to the group of species having more or less the same number of axial ribs on early whorls and on the body whorl. Almost the same can be said of L. costaricensis except that it has 2.5 to 2.75 protoconch volutions. Material.—29 lots with a total of 136 specimens as listed below: Nn BULLETIN 366 3 x70 Text-figuré 61.—Lepicythara terminula (Dall). USNM 495820 (ex 163902). USGS Station 3300: Shell Creek, De Soto County Florida, Caloosahatchee Formation. Height 11.5 mm, width 5.3 mm. 1, front view; 1 spec., USNM 97338: lectotype. Caloosahatchee River, Florida. Caloosahatchee Formation (Plio- Pleistocene). | spec., USNM 647034: paralectotype. Caloosahat- chee River, Florida. Caloosahatchee Formation (Plio-Pleistocene). 35 spec., USNM 163902, USGS Station 3300: Shell Creek, DeSoto County, Florida. Caloosahatchee Formation (Plio-Pleistocene). USNM 113175: Shell Creek, De Soto County, Florida. Caloosahatchee Formation (Plio- Pleistocene). 1 spec.. NMB locality 11187: Spoil banks, north side of Caloosahatchee River, 5.5 miles west of ee) spec., 2, apical view; 3, enlargement of apical view. Ortona Lock, Glades County, Florida. Caloosa- hatchee Formation and unnamed Caloosahatchee mixed (Plio-Pleistocene). 5 spec., NMB locality 18959: Quality Aggregates Pit, Sarasota County, Florida (27’21'N, 82”"26'W). Pinecrest beds (Pliocene). 4 spec., NMB locality 18960: Shell Pit south of Ar- cadia, DeSoto County, Florida (27"03'00"N, 81”49'30"/W). Caloosahatchee Formation (Plio- Pleistocene). 19 spec., UF 47779: Macasphalt Shell Pit (SOOO1), Sarasota County, Florida. Plio-Pleistocene. 13 spec., UF 61417: Fort Basinger 02 (OB002), Okee- chobee County, Florida. Pinecrest beds (Pliocene). FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG Si, S) Dats) 4 x70 Text-figure 62.—Lepicythara terminula (Dall). USNM 495821 (ex 163902) USGS Station 3300: Shell Creek, De Soto County, Florida, Caloosahatchee Formation. Height 16.5 mm, width 7.3 mm. 1, front view of spire whorls; 2, enlargement of apical area; 3, apical area; 4, enlargement of apical view. 2 spec., UF 49149: Kissimmee River 01 (HGOO1), 2 spec., UF 11084: Macasphalt Shell Pit (SOOO1), Highlands County, Florida. Pinecrest beds/Caloo- Sarasota County, Florida. Plio-Pleistocene. sahatchee Formation (Plio-Pleistocene). 2 spec., UF 47371: Caloosahatchee Canal 06 2 spec., UF 42662: Mule Pen (CRO04), Collier (GLO025), Glades County, Florida. Pleistocene. County, Florida. Pinecrest beds (Pliocene). 6 spec., UF 59983: Fort Basinger 02 (OBOO2), 2 spec., UF 61635: Fort Basinger 01 (OBOO1), Okeechobee County, Florida. Pinecrest beds (Pli- Okeechobee County, Florida. Pinecrest beds (Pli- ocene). ocene). 1 spec., UF 62383: Fort Basinger 04 (OBOO8), Nn ioe) BULLETIN 366 4 x70 Text-figure 63.—Lepicythara terminula (Dall). USNM 495822 (ex 163902). USGS Station 3300: Shell Creek, De Soto County, Florida. Caloosahatchee Formation. Height 14.1 mm, width 5.6 mm. 1, view of spire whorls from left side; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view. Okeechobee County, Florida. Pinecrest beds (Pli- (HNOO2), Hendry County, Florida. Pinecrest beds ocene). (Pliocene). | spec., UF 61394: Fort Basinger 02 (OBOO2), 2 spec., UF 61036: Fort Basinger 01 (OBOO1), Okeechobee County, Florida. Pinecrest beds (Pli- Okeechobee County, Florida. Caloosahatchee ocene). Formation (Plio-Pleistocene). 2 spec., UF 2835: Caloosahatchee River O1 3 spec., UF 46672: Clewiston (HNO17), Hendry 19 18 17 14 13 11 10 0 FossitL LEPICYTHARA IN TROPICAL AMERICA: JUNG 59 4 5 6 7 8 Text-figure 64.—(Restored) height/width diagram of L. terminula. i) County, Florida. Caloosahatchee Formation (Plio- Pleistocene). spec., UF 57865: Caloosahatchee Canal 04 (GLOO9), Glades County, Florida. Caloosahat- chee/Bermont formations (Plio-Pleistocene). spec., UF 31933: Macasphalt Shell Pit (SOOO1). Sarasota County, Florida. Plio-Pleistocene. spec., UF 13441: Bird Road (DAOO1), Dade County, Florida. Pinecrest beds (Pliocene). spec., UF 29119: Macasphalt Shell Pit (SOOO1), Sarasota County, Florida. Plio-Pleistocene. Text-figure 65.—Lepicythara toroensis n. sp. NMB H 18143. Ho- lotype. NMB locality 18724; north side of Valiente Peninsula, Proy- ince of Bocas del Toro, Panama. Bruno Bluff. Shark Hole Point Formation. Height 19.3 mm, width 9.0 mm. 1, front view; 2, rear view; 3, from right side. 2 spec., UF 50624: Fort Basinger 01 (OBOO1), Okeechobee County, Florida. Pinecrest beds (Plhi- ocene). 8 spec., UF 47824: Macasphalt Shell Pit (SOOO1), Sarasota County, Florida. Plio-Pleistocene. 2 spec., UF 42992: Mule Pen (CRO04), Collier County, Florida. Pinecrest beds (Pliocene). 1 spec., UF 60107: Cochran Shell Pit (HNOO4), Hendry County, Florida. Caloosahatchee Forma- tion (Plio-Pleistocene). 4 spec., UF 22190: Macasphalt Shell Pit (SOO01), Sarasota County, Florida. Plio-Pleistocene. 60 BULLETIN 366 Table 13.—Measurements (in mm) of Lepicythara terminula Table 13.—Continued. (Dall, 1890). Height/ Height/ Restored width Restored width Specimen height Width ratio Specimen height Width ratio 14] 67 2.10 USNM 97338 14.5 6.2 2.34 12.7 6.2 2.05 USNM 647034 15:9 6.6 2.41 1223) 32. 2.37 USNM 163902 13.6 5.8 2.34 11.8 Sys) 2723) UES 53 2.17 17.8 7.0 2.54 16.5 7.3 2.26 12.7 5.6 2.27 15.6 6.7 2233) 14.3 6.7 2.13 17.1 6.9 2.48 14.0 6.4 2.19 14.1 5.6 252 13.0 5.4 2.41 16.4 7.0 2.34 : 13:3: 6.2 2.15 14.8 6.3 2.35 17.0 7.3 2:33 1522 6.6 2.30 17.8 eS) DSi, 13.1 5.8 2.26 18.7 8.4 2723 15.0 6.6 2.27 15.8 6.9 2229) 12.2 5.6 2.18 ies} 8.3 2.33 16.2 6.8 2.38 NES} 7.0 2.19 18.6 Teal 2.62 13.1 6.4 2.05 16.8 6.8 2.47 14.0 6.6 Dal: 16.9 7.6 2.22 14.2 6.8 2.09 13.9 6.0 232 14.5 Re 2.01 17.9 Wel BSD 14.9 6.9 2.16 13.5 6.1 22M 16.8 7.8 DAS 14.9 6.1 2.44 14.8 7.0 Qalel 14.6 6.0 2.43 13.8 6.7 2.06 12.9 5.9 2.19 Sy 6.5 2.32 15:3) 6.3 2.43 16.6 6.9 2.40 13.0 55 2.36 ley? 7.2 el 13.0 5.6 2:32 16.3 FES) Dai; 14.0 6.2 2.26 13.8 6.1 2.26 15.7 6.6 2.38 17.0 6.8 2.50 16.9 6.9 2.45 16.7 6.6 293 16.9 Wed 2.35 16.6 7.0 2.37. 10.6 4.5 2.36 15.9 7.4 DAS 8.6 4.1 2.10 19.4 Te 2°59 12.2 5:3 2.30 155) 72 PIAS) 11.1 5.0 DD, 12.5 Sy 2.19 1527, Thal 2.21 1229 6.0 2.15 16.6 V2: 2.31 13.5 5.8 233) 15.9 6.7 237) 12.3 5.5 2.24 18.3 74 2.47 12.2 5.8 2.10 17.2 7.4 2.32 2 33 2.28 18.5 7.6 2.43 13*5 6.3 2.14 15.0 5.8 DESY 15.8 7.0 2.26 14.8 6.1 2.43 14.0 6.0 2.33 15.2 6.6 2.30 15.7 7.6 2.07 15.9 7.0 D2, 13.9 5.9 2.36 16.4 2 2.28 16.4 6.7 2.45 16.4 6.8 2.41 14.9 6.8 2.19 15.6 6.1 2.56 18.3 7.8 2.35 NSyo7/ 6.8 2331 14.5 6.1 2.38 14.3 6.2 D3] 17.6 8.0 2.20 15.5 6.3 2.46 11.6 5:3. Dad) 13.8 6.2 223 12.3 5.9 2.08 18.1 6.8 2.66 18.2 7.6 2539) 15.4 6.8 2.26 16.8 7.0 2.40 14.0 6.3 DDD. 17.8 esl, 2-9) 13.4 6.2 26 2. 16.2 TS) 16 FossiIL LEPICYTHARA IN TROPICAL AMERICA: JUNG 61 4 x70 3 x35 Text-figure 66.—Lepicythara toroensis n. sp. NMB H 18144. Paratype. NMB locality 18724: north side of Valiente Peninsula, Province of Bocas del Toro, Panama, Bruno Bluff, Shark Hole Point Formation. Height 5.0 mm, width 2.3 mm. 1, oblique rear view: 2, enlargement of apcal area; 3, apical view; 4, enlargement of apical view. Measurements.—(See Table 13, Text-fig. 64.) Lepicythara toroensis, new species Occurrence.—This species is recorded from for- Text-figures 65—66 mations of Pliocene and Pleistocene age of southern Florida (for details see under **‘Material”’). : Description.—Of large size, strongly biconic and Distribution.—So far this species is not known from stout. Protoconch consists of 2.5 volutions. The sur- outside southern Florida. face of the first two and a littlke more volutions is 62 BULLETIN 366 smooth, the remainder of he protoconch sculptured by four opisthocline to opisthocyrt axial riblets. Apex slightly pointed. Number of teleoconch whorls up to 5.75; their profile is straight on early whorls with an angulation near the abapical suture, but slightly convex on later whorls. Early teleoconch whorls sculptured by eight to nine orthocline to slightly opisthocline axial ribs. The number of axial ribs per whorl gradually in- creases reaching twelve to thirteen on the body whorl The axial ribs of the first two teleoconch whorls are somewhat pointed at the periphery thus projecting a little over the abapical suture. Interspaces of axial ribs concave, sculptured by four to five incised, spiral lines on the first teleoconch whorl and increasing in number to eleven on the penultimate whorl There are a few secondary incised, spiral lines. All spiral lines cross the axial ribs. Suture shallow. Aperture narrow. Outer lip thickened. Sinus adjoining suture moderately deep. Inner surface of outer lip smooth, with a prominent ridge parallel to the sharp edge of the outer lip ex- tending from the sinus to the beginning of the anterior canal. Parietal callus somewhat thickened near sinus, columellar callus moderately prominent. Anterior ca- nal straight and short. Holotype.—NMB H 18143 (Text-fig. 65). Dimensions of holotype.—Height 19.3 mm, width 9.0 mm. Type locality.—NMB locality 18724 (=PPP 2227 north side of Valiente Peninsula, Province of Bocas del Toro, Panama. Bruno Bluff. Shark Hole Point For- mation (Early Pliocene). See Coates, 1999b, map 5, p. 290: 1999cy section 125 p) 312: Remarks.—This species is based on seven speci- mens only. Three of them are adult, but only one—the holotype—has a moderately well-preserved proto- conch. The other four specimens are juveniles. The type lot of L. toroensis from NMB locality 18724 was collected in 1995. The lot from NMB locality 17851 (=PPP 379) consisting of three paratypes was collected in 1988. Both localities are exactly the same (Coates, 1999b, map 5, p. 290; 1999c, section 12, p. 312). The fossils from both were collected from a 20 cm thick shell bed with leached mollusks situated about 8 m above sea level and hence were taken from fallen blocks. The third lot consisting of a single paratype from NMB locality 17850 (=PPP 376) was collected about 8 m below the other two localities, i.e., at about sea level (Coates, 1999b, map 5, p. 290; 1999c, section WO SIP) Comparisons.—L. toroensis is the largest species described herein and belongs to the group of species having more axial ribs on the body whorl than on early whorls. L. disclusa is smaller than L. toroensis and has a smaller apical angle, i.e., it is less stout. Its proto- 1 2 3 all x5 Text-figure 67.—Lepicythara turrita (Mansfield). USNM 369984. Holotype. UGSG Station 3671 Hosford, Liberty County, Florida. Jackson Bluff Formation (Choctawhatchee Group). Height 12.2 mm, width 5.6 mm. 1, front view; 2, rear view; 3, from right side. conch consists of 2.75 to 3 volutions, whereas that of L. toroensis of only 2.5. The number of opisthocline to opisthocyrt axial riblets on the late part of the pro- toconch is much larger in L. disclusa. Finally the num- ber of axial ribs in L. disclusa is 8—9 on early teleo- conch whorls and 9-10 on the body whorl The cor- responding figures in L. toroensis are also 8—9 on early whorls, but 12—13 on the body whorl. L. heptagona is also smaller than L. torensis and also has a smaller apical angle and therefore is more slender. Its protoconch consists of 2.25 volutions, that of L. toroensis of 2.5. the number of opisthocline to opisthocyrt axial riblets on the late part of the proto- conch is up to eight in L. heptagona, but only up to four in L. toroensis. The number of axial ribs in L. heptagona is seven to eight on early teleoconch whorls and eight to nine on the body whorl, which is less than the corresponding numbers in L. toroensis. L. toroensis may also be compared with L. terminula (see p. 55 for more information). Material.—Three lots with a total of only seven specimens as listed below: | spec., NMB locality 17850 (=PPP 376): Bruno Bluff, outer coast of Valiente Peninsula, Bocas del Toro, Panama. Shark Hole Point Formation (Early Pliocene). Paratype. 3 spec., NMB locality 17891 (=PPP 379): Bruno Bluff (as above). Shark Hole Point Formation (Early Pliocene). Paratypes. 3 spec., NMB locality 18724 (=PPP 2227): Bruno FosstL LEPICYTHARA IN TROPICAL AMERICA: JUNG 63 4 x70 Text-figure 68.—Lepicythara turrita (Mansfield). USNM 495824 (ex 369986). USGS Station 3421: Harveys Creek, about half a mile above the abandoned mill, Leon County, Florida. Jackson Bluff Formation (Choctawhatchee Group). Height 9.7 mm, width 4.5 mm. 1, rear view; 2, enlargement of apical area; 3, apical area; 4, enlargement of apical view. Bluff (as above). Shark Hole Point Formation (Early Pliocene). Holotype and two paratypes. Measurements.—(See Table 14.) Occurrence.—This species is recorded from the fol- lowing NMB localities: 17950, 17851, 18724: all Bru- no Bluff, outer coast of the Valiente Peninsula, Prov- ince of Bocas del Toro, Panama. Shark Hole Forma- tion (Early Pliocene). Distribution Not known from outside the type area. Etymology.—Refers to the geographic name of the Province of Bocas del Toro, Panama. 64 BULLETIN 366 3 x20 4 x65 Text-figure 69.—Lepicythara turrita (Mansfield). UF 102876 (ex 71582). Alligator Alley (CROO7), Collier County, Florida, Pinecrest beds. Height 10.9 mm, width 5.0 mm. 1, rear view; 2 Lepicythara turrita (Mansfield, 1930) Text-figures 67—70 Brachycythara turrita Mansfield, 1930, p. 43, pl. 3, fig. 8. Description.—Of small to medium size, biconic, rather stout. Protoconch consists of 2.75 to 3 volutions. Surface of the first two volutions smooth, remainder 2, enlargement of apical area; 3, apical area; 4, enlargement of apical view. of the protoconch sculptured by thirteen opisthocyrt axial riblets. Number of teleoconch whorls almost five, their profile straight on early spire whorls, convex on late spire whorls. On all spire whorls, there is a slight concavity adjoining the adapical suture. The first two to three teleoconch whorls may be somewhat carinated near the abapical suture thus overhanging it. Early te- FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 65 Table 14.—Measurements (in mm) of Lepicythara toroensis new species. Height/ Restored width Specimen height Width rao NMB locality 17850 19.6 93 2.11 NMB locality 18724 19.5 8.9 29) 19.3 9.0 2.14 leoconch whorls sculptured by nine practically ortho- cline axial ribs, late whorls by eight. The axial ribs are narrow adapically and much wider abapically. Inter- spaces of axial ribs strongly concave, sculptured by three to seven incised, spiral lines on spire whorls. On late spiral whorls secondary incised, spiral lines are introduced. All spiral lines cross the axial ribs. Suture not deep. Aperture narrow. Outer lip thickened. Sinus adjoining suture moderately deep. Inner surface of out- er lip smooth, but with a well-developed ridge parallel to the sharp edge of the outer lip extending from the sinus to the beginning of the anterior canal. Columellar and parietal calluses moderately prominent. Anterior canal straight, moderately narrow, and short. Holotype.—USNM 369984 (Text-fig. 68). Dimensions of holotype.—Height 12.2 mm, width 5.6 mm. Type locality.—USGS Station 3671: Hosford, Lib- erty County, Florida. Jackson Bluff Formation (Plio- cene). Remarks.—This species is described as being of small to medium size. Actually there is a single spec- imen from the Pliocene Pinecrest beds of Basinger, Okeechobee County (UF 48019), which has a restored height of 14.9 mm, and should therefore be called “large” according to the definition given on page 9. L. turrita is being described as having nine axial ribs on early teleoconch whorls and eight axial ribs on late teleoconch whorls. There are, however, a few speci- mens with ten axial ribs on early, and nine axial ribs on late teleoconch whorls. It is thus practically the only species having more axial ribs on early whorls than on the body whorl. In the above description, it is stated that the first two to three teleoconch whorls may be somewhat car- inated near the abapical suture. One of the figured specimens from the Pliocene Pinecrest beds (Text-fig. 69.2) looks like an exception in having an almost straight profile without carination on early teleoconch whorls. Other Pliocene specimens, however, do have a carination near the abapical suture. Comparisons.—L. turrita and L. aff. turrita are the only species of the genus having less axial ribs on the body whorl than on early teleoconch whorls. Therefore 15 e 14 13 e e e 12 oe Lene e e 11 e e e eo @ ee ee 10 A e e e e e 9 > e 0 4 5 6 7 Text-figure 70.—(Restored) height/width diagram of L. turrita. they cannot really be compared to other species of Le- picythara. The two species are compared under L. aff. turrita. Material.—Eight lots with a total of 34 specimens as listed below: 1 spec., USNM 369984: holotype; USGS Station 3671: Hosford, Liberty County, Florida. Jackson Bluff Formation (Pliocene). 12 spec., USNM 369985: paratypes; USGS Station 3421: Harveys Creek, about half mile above the abandoned mill, Leon County, Florida. Jackson Bluff Formation (Pliocene). 2 spec., USNM 369986: paratypes; USGS Station 3421: Harveys Creek, approx. one half mile above an abandoned mill, Leon County, Florida. Jackson Bluff Formation (Pliocene). 2 spec., UF 6952: Harveys Creek (LNOO3), Leon County, Florida. Jackson Bluff Formation (Plio- cene). 66 BULLETIN 366 Table 15.—Measurements (in mm) of Lepicythara turrita (Mans- field, 1930). Height/ Restored width Specimen height Width ratio USNM 369984 125) 5.6 2.23 USNM 369985 SHY) 4.6 PI) 9.6 4.9 1.96 10.1 52 1.94 98 4.9 2.00 10.3 Shs) 1.87 10.3 5.6 1.84 10.1 5.0 2.02 10.6 5.3 2.00 Me9, 523, DZS 11.8 Dif) 2.07 USNM 369986 1k9, 5.4 2.20 9.7 4.5 2.16 UF 6952 9.4 4.7 2.00 12.1 6.4 1.89 UF 71582 10.9 5:0 2.18 Te 7; 5.8 2.02 UF 69302 8.9 4.5 1.98 9.0 4.9 1.84 10.6 5.4 1.96 10.3 5:3 1.94 10.7 5:3 2.02 10.8 5:5) 1.96 10.1 5.0 2.02 11.8 6.0 1.97 UF 69296 9.0 5.0 1.80 ies 6.0 1.88 UF 48019 12:5 6.1 2.05 14.9 Tal 2.10 2 spec., UF 71582: Alligator Alley (CROO7), Collier County, Florida. Pinecrest beds (Pliocene). 10 spec., UF 69302: Jackson Bluff (LNO04), Leon County, Florida. Jackson Bluff Formation (Plio- cene). 3 spec., UF 69296: Jackson Bluff (LNOO4), Leon County, Florida. Jackson Bluff Formation (Plio- cene). spec., UF 48019: Basinger (2664), Okeechobee County, Florida. Pinecrest beds (Pliocene). ie) Measurements.—(See Table 15 and Text-figure 70.) Occurrence.—This species is recorded from the Jackson Bluff Formation and the Pinecrest beds of Florida. Distribution.—So far this species is not known from outside Florida. Lepicythara aff. turrita (Mansfield) Text-figures 71-72 Remarks.—There are four specimens of this species occurring in the Late Miocene Nancy Point Formation. One practically complete specimen has been collected Text-figure 71.—Lepicythara atf. turrita (Mansfield). NMB H 18151. NMB locality 18705: westernmost part of the south coast of the Valiente Peninsula, Province of Bocas del Toro, Panama. Nancy Point Formation. Height 17.7 mm, width 7.9 mm. 1, front view: 2, rear view; 3, from right side. at NMB locality 18705 (=PPP 2206), which is situated in the westernmost part of the south coast of the Va- liente Peninsula, Province of Bocas del Toro, Panama. This is the largest of all four specimens (Text-fig. 71). The remaining three specimens are adult and have been collected at two localities on Finger Island, which is situated west of Bluefield Bay, Valiente Peninsula, Bocas del Toro, Panama. One specimen was collected at NMB locality 17824 (=PPP 477), the other two at NMB locality 18375 (=PPP 1996). For the exact lo- cation of these localities see Coates (1999b, map 5, insets A and C, p. 291; 1999c, section 14, p. 318; 1999c, section 15, p. 322). L. att. turrita is a large species of the genus. Its protoconch consists of a littke more than 2.75 volu- tions, the first two of which are smooth and the re- FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 67 3 x100 % POT ES Pty , <9 — ¢ a 5 Fr x at le SS > meas ~ er) CS ee 5 x50 6 x80 Text-figure 72.—Lepicythara aff. turrita (Mansfield). NMB H 18151 (same specimen as Text-fig. 72) NMB locality 18705: westernmost part of the south coast of the Valiente Peninsula, Province of Bocas del Toro, Panama. Nancy Point Formation. Height 17.7 mm, width 7.9 mm. I, rear view of spire whorls; 2, enlargement of apical area; 3, further enlargement of apical area: 4, apical view; 5, enlargement of apical view: 6, further enlargement of apical view. 68 BULLETIN 366 Table 16.—Measurements (in mm) of Lepicythara aff. turrita (in mm). Height/ Restored width Specimen height Width ratio NMB locality 18705 Wied 7.9 2.24 NMB locality 17824 14.9 7.0 213 NMB locality 18375 14.8 7.0 Pela 15.8 7.0 2.26 mainder sculptured by up to fourteen opisthocline to opisthocyrt axial riblets. There are up to 5.25 teleo- conch whorls. The profile of the early teleoconch whorls is straight, and there is a small angulation near the abapical suture. The profile of the late whorls is slightly convex. There are eight to nine axial ribs on the first teleoconch whorl, but only seven on late whorls. The spiral sculpture of the body whorl consists not only of primary and secondary, but also of some tertiary incised lines. This species is larger than L. tu- rrita, and there are no tertiary spiral incised lines on the body whorl of L. turrita. The two species, however, have two important features in common; their proto- conchs are practically identical, and both have more axial ribs on early whorls than on late whorls. This latter feature is rare in Lepicythara, having been ob- served only in L. turrita and L. atf. turrita. Measurements.—(See Table 16.) Lepicythara sp. A Text-figure 73 ?Cythara heptagona (Gabb). Brown and Pilsbry, 1911, p. 345. Lepicythara heptagona (Gabb). Woodring, 1970, p. 390. pl. 60, no. 4, pl. 64, no. 11. Remarks.—Woodring (1970, p. 390) recorded spec- imens from a number of localities within the Gatun Formation of Panama under the name of L. heptagona (Gabb). The single specimen reported by Brown and Pilsbry (1911, p. 345) under this name probably rep- resents the same species. Three specimens of Woodring’s material from three different localities are at hand. The localities are: 1. USGS 8382: railroad cuts west of Gatun Dam, Canal area, USGS 8383: Caribbean coast, west of Rio San Miguel, Panama, 3. USGS 16926: westernmost cut on Panama Rail- road cutoff south of Fort Davis, 1.9 km northeast of Gatun railroad station, Canal area. in) The specimen from USGS 8383 is a fragment and therefore does not provide much morphological infor- mation. The other two specimens are of medium size, Table 17.—Measurements (in mm) of Lepicythara sp. A (in mm). Height/ Restored width Specimen height Width ratio USGS 16926 12.8 5.0 2.56 USGS 8382 12.6 3:5) 2229) biconic, and slender, L. heptagona from the Dominican Republic on the other hand is of large size, also bi- conic, but rather slender to moderately stout. The num- ber of axial ribs on early whorls is seven to eight, and on the body whorl eight to nine like in L. heptagona from the Dominican Republic. The protoconch con- sists of 3.25 volutions, and its apex is pointed, whereas the protoconch of L. heptagona trom the Dominican Republic only has 2.25 volutions, and its apex is not pointed. Surprisingly, the large PPP collections have yielded only a single fragmentary specimen from NMB locality 17641 (=PPP 223): Sabanita, Panama; lower Gatun Formation (Coates, 1999b, map 1, inset, p. 287; 1999c, section 1, p. 301). This specimen has an incomplete protoconch, and only a few early teleo- conch whorls are preserved. Based on this information is obvious that the Lepicythara from the Gatun For- mation of Panama cannot be identified as L. hepta- gona, but probably represents some other species. The existing materials, however, are considered insufficient for a formal description. Measurements.—(See Table 17.) Lepicythara sp. B Remarks.—Woodring (1970, p. 391) mentioned a lot from USGS Station 8477 (Rio Tuira between Li- mones and Rio Cube, Darien, Panama), which he iden- tified as L. heptagona (Gabb). This locality is part of the Middle Miocene Tuira Formation. The lot consists of four worn specimens. Three of them are fragmen- tary, their body whorl not being preserved. The fourth is an adult specimen lacking its protoconch (restored height 14.0 mm, width 5.7 mm, ratio 2.46). They all are not preserved well enough to be illustrated. These specimens cannot be identified as L. heptagona (Gabb). Two of the fragments have an apparently com- plete protoconch which, however, is badly preserved. Although not clearly recognizable, these two proto- conchs seem to consist of a littke more than three vo- lutions. The protoconch of L. heptagona trom the Do- minican Republic on the other hand has only 2.25 vo- lutions The number of axial ribs on early whorls is seven in the material from Darien and seven to eight in L. heptagona from the Dominican Republic. The corresponding number on the body whorl is six to sey- en in the material from Darien but eight to nine in L. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 69 eee 4 x60 5 x100 Text-figure 73.—Lepicythara sp. A. USNM 509803. USGS Station 16926: westernmost cut on Panama Railroad cutoff south of Fort Davis, 1.9 km northeast of Gatun railroad station. Canal area. Middle part of Gatun Formation. Height 12.8 mm, width 5.0 mm. 1, rear view; 2, enlargement of apical area; 3, apical view; 4, enlargement of apical view: 5, further enlargement of apical view. 70 BULLETIN 366 heptagona from the Dominican Republic. Due to the lack of more and better preserved material it is not possible to positively identify the Lepicythara from Darien. The large PPP collections at the NMB do not contain a single specimen of this species. Lepicythara sp. C Remarks.—There are three specimens from the Late Miocene Nancy Point Formation of Finger Island, west of Bluefied Bay, Valiente Peninsula, Province of Bocas del Toro, Panama, which were collected on different occassions and therefore carry different locality num- bers: NMB 17629 (=PPP 191), NMB 17824 (=PPP 477), and NMB 18711 (=PPP 2212). For exact loca- tion see Coates (1999b, map 5, inset A, p. 291; 1999c, section 14, p. 318). Two of these specimens are incomplete juveniles, and the third is a worn adult lacking its protoconch. One of the juveniles has an incompletely preserved protoconch, which consists of abut 2.5 volutions. On its last part a few opisthocryt axial riblets are recog- nizable. The adult specimen from NMB locality 17824 is fairly large (restored height 15.1 mm, width 7.2 mm, ratio 2.10). The profile of the early teleoconch whorls is straight, with a slight angulation near the abapical suture, and that of late whorls is slightly convex. The number of axial ribs per whorl is nine on early whorls and 12 on the body whorl. The preservation of this material is insufficient to allow meaningful compari- sons with described species. Lepicythara sp. D Text-figure 74 Remarks.—A single specimen from NMB locality 17757 (=PPP 275) is available. This locality is situ- ated near Punta Judas on the Pacific coast of the Prov- ince of Puntarenas, Costa Rica (for exact location see Jung 1995, p. 44, fig. 1), and the age is probably Late Miocene. The specimen is fairly large (restored height 14.1 mm, width 7.4 mm, ratio 1.91) and stout, i.e., it has a large apical angle. Unfortunately it is worn and partly encrusted, so that some features cannot be ob- served. The protoconch is not preserved. The profile of the early teleoconch whorls is straight, that of late whorls slightly convex. The number of axial ribs per whorl on early whorls cannot be determined, but is probably eight as on the body whorl. The anterior ca- nal is short and slightly twisted to the left. Lepicythara sp. E Remarks.—A_ single specimen is available from NMB locality 19126 (=PPP 3437): Cueva de Angos- tura on Rio Santaigo, Borbon, northwestern Ecuador; all x5 Text-figure 74.—Lepicythara sp. D. NMB H 18145. NMB locality 17757: near Punta Judas, Pacific coast of the Province of Puntarenas, Costa Rica. Probably Late Miocene. Height 13.6 mm, width 7.4 mm. |, front view; 2, rear view; 3, from right side; 4, apical view. Angostura Formation (Late Miocene) (Whittaker, 1988, p. 10). The specimen is of medium size (restored height 12.5 mm, width 4.9 mm, ratio 2.55) and slender. It is somewhat deformed, its main axis not being quite straight. Its dorsal side has been exposed to erosion, and the sculpture is therefore not preserved. The tip of the protoconch is missing, and the sculpture on the last volution of the protoconch is hardly recognizable. The number of teleoconch whorls is 5.25, their profile is straight on early whorls and slightly convex on late whorls. The number of axial ribs 1s seven on early whorls and nine on the body whorl. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 7AM REFERENCES CITED Akers, W.H. 1972. Planktonic Foraminifera and Biostratigraphy of some Neogoen Formations, Northern Florida and Atlantic Coastal plain—Tulane Studies in Geology and Paleon- tology, vol. 9, pp. 1-139, pl. 1-60, fig. 1-4, 1 map. 1979. Ancient Environments and Geological Ages in Mexico. In Proceedings of the International symposium on Marine biogeography and Evolution in the Southern Hemisphere. Auckland, New Zealand, 17—20 July 1978. New Zealand Department of Scientific and Industrial Research Infor- mation Series, vol. 2, pp. 491-499. Bolli, H.M. and Saunders, J.B. 1985. Oligocene to Holocene low latitude planktic foraminifera. In Bolli, H.M., Saunders, J.B., and Perch-Nielson, K., eds., Plankton stratigraphy. Cambridge University Press, Cambridge, pp. 155-262. Brann, D.C. and Kent, L.S. 1960. Catalogue of type and figured specimens in the Paleon- tological Research Institution. Bulletins of American Pa- leontology, vol. 40, no. 184, 995 p. Brown, A.P. and Pilsbry, H.A. 1911. Fauna of the Gatun Formation, Isthmus of Panama. Pro- ceedings of the Academy of Natural Sciences of Phila- delphia, vol. 63, pp. 336-373. Carter, J.G. 1984. Summary of Lithostratigraphy and Biostratography for the Coastal Plain of the South Eastern United States. Bio- stratigraphy Newsletter No. 2. Coates, A.G. 1999a._ Lithostratigraphy of the Neogene strata of the Caribbean Coast from Limon, Costa Rica, to Colon, Panama. /n Col- lins, L.S., and Coates, A.G., eds., A Paleobiotic Survey of Caribbean Faunas from the Neogene of the Isthmus of Panama. Bulletins of American Paleontology, no. 357, pp. 17-38. 1999b. Appendix A: maps. /n Collins, L.S., and Coates, A.G., eds., A Paleobiotic Survey of Caribbean Faunas from the Neogene of the Isthmus of Panama. Bulletins of American Paleontology, no. 357, pp. 287-298. 1999c. Appendix B: stratigraphic sections. /n Collins, L.S., and Coates, A.G., eds., A Paleobiotic Survey of Caribbean Faunas from the Neogene of the Isthmus of Panama. Bul- letins of American Paleontology, no. 357, pp. 299-348. Collins, L.S. and Coates, A.G., eds. 1999. A Paleobiotic Survey of Caribbean Faunas from the Neo- gene of the Isthmus of Panama. Bulletins of American Paleontology, no. 357. Dall, W.H. 1889. Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78) and in the Caribbean Sea (1879-80), by the U.S Coast Survey Steamer “Blake”, Lieut. Commander C.D. Sigs- bee, U.S.N., and Commander J.R. Bartlett, U.S.N., commanding. XIXX. Report on the Mollusca. Part II. Gastropoda and Scaphopoda. Bulletin of the Museum of Comparative Zoology, no. 18, 492 pp. 1890. Contributions to the Tertiary fauna of Florida; with es- pecial reference to the Miocene silex-beds of Tampa and the Pliocene beds of the Caloosahatchee River. Transac- tions of the Wagner Free Institute of Science, Philadel- phia, vol. 3, no. 1, pp. 1-200. Gabb, W.M. 1873. On the topography and geology of Santo Domingo. Trans- actions of the American Philosophical Society (n.s.), vol. 15, pp. 49-259. Gardner, J. 1937. The Molluscan fauna of the Alum Buff Group of Florida. Part VI. Pteropoda, Opisthobranchia, and Ctenobranchia (in part). U. S. Geological Survey Professional Paper 142- FE pp. 251-435. Jackson, J.B.C., Todd, J.A., Fortunato, H., and Jung, P. 1999. Diversity and Assemblages of Neogene Caribbean Mol- lusca of Lower Central America. /n Collins, L.S.,.and Coates, A.G., eds., A Paleobiotic Survey of Caribbean Faunas from the Neogene of the Isthmus of Panama. Bul- letins of American Paleontology, no. 357, pp. 193-230. Jung, P. 1969. Miocene and Pliocene mollusks from Trinidad. Bulletins of American Paleontology, vol. 55, no. 247, pp. 289-657. 1989. Revision of the Strombina-Group (Gastropoda: Colum- bellidae), fossil and living. Distribution, biostratigraphy, systematics. Schweizerische Paléiontologische Abhand- lungen, vol. 111, 298 pp. 1995. Judaphos, a new genus of buccinid Gastropod from the Neogene of Costa Rica. The Veliger, vo. 38, no. 1, pp. 43-46. Mansfield, W.C. 1930. Miocene gastropods and scaphopods of the Choctawhat- chee Formation of Florida. Florida Geological Survey Bulletin 3, pp. 1-185. Maury, C.J. 1917. Santo Domingo type sections and fossils. Pt. 1: Mollusca. Bulletins of American Paleontology, vol. 5, no. 29, pp. 1-251. Oinoomikado, T. 1939. Miocene Mollusca from the neighbourhood of Cucurrupi, Department of Choco, Colombia. Journal of the Geolog- ical Society of Japan, vol. 46, pp. 617-630. Olsson, A.A. 1922. The Miocene of northern Costa Rica. Bulletins of Amer- ican Paleontology, vol. 9, no. 39, pp. 1-168. 1964. Neogene mollusks from northwestern Ecuador. Paleonto- logical Research Institution, Ithaca, New York, 256 pp. Perrilliat, M.C. 1972. Monografia de los moluscos del Mioceno medio de Santa Rosa, Veracruz, Mexico. Parte I. (Gasteropodos: Fiussu- rellidae a Olividae). Paleontologia Mexicana, vol. 32, pp. 1-130. 1973. Monografia de los moluscos del Mioceno medio de Santa Rosa, Veracruz, Mexico. Parte II. (Gasteropodos: Mitridae a Terebridae). Paleontologia Mexicana, vol. 35, pp. 1-97. Pilsbry, H.A. 1922. Revision of W.M. Gabb’s Tertiary Mollusca of Santo Do- mingo. Proceedings of the Academy of Natural Sciences of Philadelphia, vol. 73, pp. 305—435. Rutsch, R.F. 1942. Die Mollusken der Springvale-Schichten (Obermiocaen) von Trinidad (Britisch-West-Indien). Verhandlungen Na- turforschende Gesellschaft Basel, vol. 54, pp. 96-182. Saunders, J.B., Jung, P., and Biju-Duval, B. 1986. Neogene Paleontology in the Northern Dominican Re- public. |. Field Surveys, Lithology, Environment, and Age. Bulletins of American Paleontology, vol. 89, no. 323, pp. 1-79. Vermeij, G.J. and Vokes, E.H. 1997. Cenozoic Muricidae of the Western Atlantic Region. Part 1D, BULLETIN 366 XII. The Subfamily Ocenebrinae (in part). Tulane Studies in Geology and Paleontology, vol. 29, no. 3, pp. 69-118. Vokes, E.H. 1994. Cenozoic Muricidae of the Western Atlantic Region. Part X. The Subfamily Muricopsinae. Tulane Studies in Ge- ology and Paleontology, vol. 26, nos. 2—4, pp. 49-160. Weisbord, N.E. 1929. Miocene Mollusca of northern Colombia. Bulletins of American Paleontology, vol. 14, no. 54, pp. 1-57. Whittaker, J.E. 1988. Benthic Cenozoic Foraminifera from Ecuador. Taxonomy and Distribution of Smaller Benthic Foraminifera from Coastal Ecuador (Late Oligocene-Late Pliocene). British Museum (Natural History), London, 194 pp. Woodring, W.P. 1970. Geology and Paleontology of Canal Zone and Adjoining Parts of Panama. Description of Tertiary Mollusks (Gas- tropods: Eulimidae, Marginellidae to Helminthoglypti- dae). U. S. Geological Survey Professional Paper 306-D, pp. 299-452. APPENDIX I. Species excluded from Lepicythara. Although the species described below does not be- long to Lepicythara, it is briefly discussed here for the sake of completeness. Lepicythara veracruzana Perrilliat Text-figure 75 1973 Lepicythara veracruzana Perrilliat. Perrilliat, p. 58, pl. 28, pp. 13-14. Description.—Of small size, not biconic, slender, Protoconch incomplete, without recognizable axial rib- lets on its last part. Number of teleoconch whorls 4.25, their profile convex. First teleoconch whorl sculptured by eight, subsequent whorls by six opisthocline to op- sithocyrt axial ribs. The width of the axial ribs is about the same from suture to suture. Interspaces of axial ribs concave, without spiral sculpture. Suture not deep. Aperture -moderately narrow. Shape of outer lip not known. Columellar and parietal calluses not preserved. Anterior canal broken. Holotype.—USNM 647172 (Text-fig. 75). Dimensions of holotype.—Height 9.0 mm, width 4.0 mm. Type locality.—USGS Station 9995: Santa Rosa, Veracruz, Mexico. For location see Perrilliat (1972, p. 11, fig. 1). Beds of late Miocene age. For more infor- A= = 2 both x5 Text-figure 75.—Lepicythara veracruzana Perrilliat. USNM 647172. Holotype. USGS Station 9995. Santa Rosa, Veracruz, Mex- ico. Beds of Late Miocene age. Height 9.0 mm, width 4.0 mm. 1, front view; 2, rear view. mation see under L. aff. heptagona, and Akers (1979, p. 497) and Vokes (1994, p. 138). Remarks.—Lepicythara veracruzana 1s based on a single, incomplete specimen, the holotype. The above description is therefore not the description of a species but the description of a specimen, which the present writer considers as undesirable to serve as type ma- terial. This species lacks several features characteriz- ing other species of the genus Lepicythara. It is not biconic in general shape, the last part of its protoconch has no recognizable axial riblets, the teleoconch whorls are not sculptured spirally, and the axial ribs of the teleoconch whorls have about the same width from suture to suture instead of being narrow adapi- cally and wider abapically. Due to the poor quality of preservation, it is not possible to assign it to another turrid genus. Material.—As mentioned above the holotype is the only available specimen. Measurements.—Restored height 9.7 mm, width 4.0 mm, ratio 2.42. Occurrence.—Known only from USGS Station 9995, the type locality: Santa Rosa, Veracruz, Mexico. Beds of Late Miocene age. See also under “type lo- cality”’, above. FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG 73 Appendix I].—In the chapter “Distribution through time and space” reference was made to Jackson et al. (1999, table 3, p. 204, appendix 1, pp. 212-213). In order to be more specific, the cited table 3 and appendix | are reproduced hereafter. A. List of 37 faunules (molluscan taxa from a single horizon at a single outcrop or closely grouped outcrops) and descriptive statistics used for the ordination analyses. Taxa are genera or subgenera. Lists of PPP numbers for each faunule are given in Appendix 3. Documentation for ages and depths are given in Appendix |. Estimated ages and depths placed in brackets. L = Limon Basin, B = Bocas del Toro Basin, NC = North Coast of Panama, C = Panama Canal Basin. Number Number of of Number Faunule Section Median Median collec- speci- of Fisher’s number Faunule name Basin number age depth tions mens taxa alpha 1 Swan Cay B 25 1.4 100 1 1,418 135 36.691 2 Cemetery Pueblo Nuevo IL; 35 1.6 75 1 452 67 21.744 3 Upper Lomas del Mar east (reef) IL, 36 1.6 WS) 12 5,986 219 44.637 4 Empalme L 34 1.6 20 5 2,188 143 34.508 5 Cangrejos Creek Ie; ay 1.6 200 5) 828 116 36.734 6 Lower Lomas del Mar east (non-reef) Ib, 36 lay © 10 6,458 304 66.229 7 Northwest Escudo de Veraguas B 10 2.0 125 4 433 49 14.206 8 Fish Hole B 22/23 2.6 70 3 331 114 61.516 9 Ground Creek B [2.6] [50] 2 723) 90 20.283 10 North central Escudo de Veraguas B 10 2.8 125 8 5,019 227 48.916 11 Rio Limoncito Ib 3.0 [30] 1 148 39 17.269 12 Chocolate Buenos Aires 1c 33 3.1 [50] 3 1,011 45 9.657 13 Bomba Ib, 29) 3.1 30 34 18,181 285 47.980 14 Agua L 29 3:3 30 2 841 53 12.565 15 Bruno Bluff B 12 BES 175 4 1,310 133 35.822 16 Cayo Agua: west side Punta Norte B 16 35) 30 8 2S 139 31.238 17 Quitaria L 29 3:5 30 7 12,690 179 29.508 18 Rio Vizcaya IU; 39 35 25 7 979 47 10.296 19 Santa Rita Ie, 32 BED: 30 2 497 81 27.462 20 Northeast Escudo de Veraguas B 10 3.6 125 4 2,588 175 42.847 21 Southeast Escudo de Veraguas B 1] 3.6 125 9 2,25) 166 41.888 22 Cayo Agua: Punta Tiberon B 19 3.6 60 9 4,001 270 65.368 23 Cayo Agua: Punta Nispero west B 19 3.6 60 6 1,339 122 32.648 24 Cayo Agua: southeast Punta Nispero B 20 3.6 60 7 3,307 175 39.562 25 Isla Popa B [4.3] [60] i 2,445 101 22.431 26 Cayo Agua: Punta Norte east B 19 4.3 60 6 2,185 124 28.663 27 Cayo Agua: Punta Piedra Roja west B 17 4.3 43 6 6,640 275 57.881 28 Quebrada Brazo Seco It 4.8 [SO] 3 240 Si 23.632 29 Shark Hole Point B 12 Syl 150 7 432 Sy7/ 17.586 30 Finger Island B 14 6.9 80 3 1,817 165 44.354 31 Rio Sand Box and Hone Creek 1b; POT Wea, 175 6 697 65 17.534 32 Rio Tuba IL, [7.7] [175] 5 9] 40 27.279 33 Rio Calzones NC 9 [8.3] (25] 2 185 43 18.598 34 Miguel de la Borda NC 6 [8.3] 25 1 699 97 30.580 35 Isla Payardi ¢€ 1 9.0 28 14 14,627 172 27.376 36 Mattress Factory € 1 9.0 28 16 W957 236 41.677 3y7/ Martin Luther King Jr. E 1 11.6 28 11 9,242 155 26.455 74 BULLETIN 366 B. Ages and paleobathymetries of faunules Age Faunule (with section #) (Ma) Depth (m) 1. Swan Cay (#25) 1.6-1.2 80-120! 2. Cemetery Pueblo Nuevo (#35) 1.7-1.5 50—100 3. Upper Lomas del Mar East (reef) (#36) 1.7-1.5 50—100 4. Empalme (#34) 1.7-1.5 10-30 5. Cangrejos Creek (#37) 1.6-1.5 150-250 6. Lomas del Mar East (non-reet) (#36) 1.9-1.5 50-100 7. Northwest Escudo de Veraguas (#10) 2.1-1.9 100-150 8. Fish Hole (#22/23) 3.0-2.2 75-100 (upper mudstone ) 40-100 (lower reef conglomerate) 9. Ground Creek (no section) 3.5-1.63 <50? 10. North-central Escudo de Veraguas (#10) 3.6-1.9 100-150 11. Rio Limoncito (no section) 6-2.4 20-40? 12. Chocolate Buenos Aires (#33) 3.2-3.0 <50? 13. Bomba (#29) 3.2-2.9 20-40 14. Agua (#29) 3.6-2.9 20-40 15. Bruno Blutf (#12) 3.6-3.3 150-200 16. Cayo Agua: West side of Punta Norte (#16) 3:5. 20-40 17. Quitéria (#29) 3.6-3.4 20-40 18. Rio Vizcaya (#39) 35 <25 19. Santa Rita (#32) 3:5) 20-40 20. Northeast Escudo de Veraguas (#10) 3.6-3.5 100-150 21. Southeast Escudo de Veraguas (#11) 3.6-3.5 100-150 22. Cayo Agua: Punta Tiburon (#19) 3.6-3.5 40-80, 23. Cayo Agua: Punta Nispero West (#19) 3.6-3.5 40-80 24. Cayo Agua: Punta Nispero Southeast (#20) 3.6-3.5 40-80 25. Isla Popa (no section) 5.0-3.5 <50? 26. Cayo Agua: Punta Norte East (#19) 5.0-3.5 40-80 27. Cayo Agua: Punta Piedra Roja West (#17) 5.0-3.5 10-75 Abundant diagnostic taxa Amphistegina gibbosa, Cassidulina curvata, Eponides antillarum, Eponides repandus, Par- arotalia rosea, Planulina ariminensis var. exor- na, Quingqueloculina lamarckiana, Siphonina pulchra based on lithostratigraphic relation to faunule #3 C. curvata, Elphidium discoidale, P. ariminensis var. exorna, Sigmoilina tenuis, Spirillina vivi- para E. discoidale, Fursenkoina pontoni, Nonionella atlantica,-Pararotalia magdalenensis, Sagrina pulchella Bulimina aculeata, Bulimina marginata, Cassidu- lina minuta, Gyroidina regularis, Planulina foveolata, Trifarina eximia based on lithostratigraphic relation to Faunule #3 Bolivina paula, B. marginata, C. curvata, C. min- uta, G. regularis, Hanzawaia concentrica, Me- lonis barleeanum, Reussella spinulosa, S. tenu- is, S. pulchra, Uvigerina laevis, Uvigerina peregrina B. marginata, E. antillarum, P. ariminensis vat. exorna, T. eximia, U. peregrina, A. gibbosa, E. discoidale, E. antillarum, Nodobaculariella cassis, P. ariminensis var. exorna, Q. lamarcki- ana, S. pulchra estimate based on sediments and mollusks same as Faunule #7 based on apparent stratigraphic relationship to Faunule #’s 13 and 17-19 Based on lithostratigraphic position between reef trends Ammonia decorata, P. magdalenensis, P. sar- mientot, Rotorbinella umbonata, S. tenuis Based on stratigraphic relations to Faunule #’s 13, 17-19 B. marginata, C. curvata, C. minuta, C. norcrosst australis, T. eximia, U. peregrina. E. discoidale, E. antillarum, F. pontoni, H. con- centrica, N. cassis, N. atlantica, Quinqueloculi- na compta, Q. lamarckiana Same as Faunule #’s 13 and 19 Ammonia becarii, A. gibbosa, Buccella hannai, N. atlantica, P. magdalenensis, Trifarina occiden- talis A. gibbosa, E. antillarum, Hauerina fragillissima, N. cassis, P. ariminensis var. exorna, R. wm- bonata Same as Faunule #7 Same as Faunule #7 Cassidulina subglobosa, E. discoidale, E. antillar- um, F. pontoni, H. concentrica, N. atlantica, P. ariminensis, R. spinulosa, S. tenuis Same as Faunule #22 Same as Faunule #22 Based on apparent stratigraphic equivalence and proximity to older Cayo Agua Fm. Same as Faunule #22 A. gibbosa, Cancris sagra, E. discoidale, E. antil- larum, Quinqueloculina spp. vs) NO tw Wo Wo Mm Bw 36. Sie FossiL LEPICYTHARA IN TROPICAL AMERICA: JUNG I! Appendix II—Continued. Nn . Quebrada Brazo Seco (no section) 5.2-4.3 . Shark Hole Point and top of Nancy Point (#12) 5.7-5.6 . Finger Island (#14) 8.25.6 . Rio Sand Box (#27) 8.7-7.2 . Rio Tuba (no section) 8.2—7.24 . Rio Calzones (#9) 11.2-5.3> . Miguel de la Borda (#6) 11.2—5.3° . Isla Payardi (#1) 9.4-8.6 Mattress Factory (#1) 9.4-8.6 Martin Luther King (#1) 11.8-11.4° <50? 100—200 60—100 150—200 150—200 15—40 15-40 Based on stratigraphic position between reef tracts and Rio Banano Fm. Bolivina barbata, Bolivina imporcata, N. atlanti- ca, P. ariminensis, U. peregrina A. gibbosa, B. barbata, C. curvata, E. antillarum, H. concentrica, Hanzawaia isidroensa, Lenticu- lina calcar, P. ariminensis, Quinqueloculina seminulum, S. pulchra, U. peregrina B. imporcata, Bolivina lowmani, Bolivina mexi- cana, C. minuta, N. atlantica, P. magdalenen- sis, R. umbonata Assumed equivalent to Faunule #31 based on ap- parent stratigraphic position Assumed equivalent to Faunule #34 A. beccarii, Bolivina merecuani, Bolivina vaugh- ani, B. hannai, P. magdalenensis, R. spinulosa, R. umbonata same as Faunule #35 same as Faunule #35 ' We used the maximum rather than the median depth because the sediments are a reef talus slump deposit. * Assumed Late Pliocene age based on inferred stratigraphic position. * Assumed equivalent to older Cayo Agua Fm. + Assumed equivalent to nearby Rio Sandbox. * Assumed Late Miocene. INDEX INBEV JOGO Cae So ce oomakn do oben ooh eee 34 /Naitxorurigy Ieee perme ageaehaoenaconoconascae Oe 7A0) Baitoa-Formationys ca = seers ei ere aioe 8, 38, 39 DasilisSanMLepiGyiInanrd janie tee ene ete toe 6, 7, 11-13 Caimitica Lepicyinarad, wasn acre eiee et ae ee ake) Sees eae: 44 @aloosahatcheesFormationte rr seen ete) eevee sicher ee 54-59 Camaronensis, JLepiCyiNQray fev.ts:. vnc) este anee sisted Chg JON IPAS Ms} GayorAeualebormationy jariernyeier saan tnen en eerie Te 2425 wD GercadowHormationpan seers 7, 8, 31, 36, 38, 44-53 (Golojrlsel Mima oom cobs ooh. dom 4 6-60, choo 6 ord area 65732) (Boer iweey so Apeoan dans odd Soy oh HEE AE Wey, Sle Zi75 740) costaricensis, Lepicythara ......... Sie UN 2 SLO Zot costaricensis, epicythara'chs «is... seo 2 65 75 Wl, 1125255226) cymella Mangilia(Cythara)) irs. 1st rencs vet Wetec) es =e eee) = 16 disclusa, Lepicythara ......... 6,7, 11, 12; 255°27—29; 43) 62 DominicansRepublic ty. eyes 1s 35, 65,8; Sl, 333134, 36,138, 39, 44, 47, 49-53, 68, 70 Eeuador® 2 eyeisie stare cascode, Pevaushsusta ye et arene teas Oy Oe Le eB Av7.0) Blorida’ 2p... ci scnecushets sien. earls si, D550; 40; 4259459 —09 104—66; GatunsRormatione asic re ce csde con ese eee iets eres 8, 68, 69 Globorotalia margaritae Zone ............ 18, 27, 28, 41, 42 GransaulliGlay Members cysts) shea ete elie a-a oe neneaiere 42 Gurabos Formation’ 2.2 ae). 4 7, 8, 31, 36, 38, 45, 46, 48, 52 Faitinpeperedstopaito + fashevacatencetneeeeee © eee ences Ges 5e39 heptagona, Lepicythara ....... Gree 2 ON 2052575289502 31, 33, 34, 38, 62, 68, 70 heptagona, Lepicythara aff... 2.2.2... OP 25332 35.02 hepiagona LepicyiharaiChe vam varie) eet es Gie75, Uy 125 31 higensis, Lepicythara s). 2. =. -<.2: 5, 6, 8, 11, 12, 34, 36-38 JacksonBlufi Hormationl <3. )uets)r-ets cline les 8, 65, 66 lopezana;, Lepicythara.. sat. 22 ssi. a By Oh oy Jl a lopezana, Lepicythara cf. Medias Aguas Formation Melajox@layalViem beter sence ciaierries Masten een eee MEXICO eS catkins eset tine sepiyceite re SvSr Bede ope tae teen anette 6, Nancy Point Formation .....5..-.... 7 O32 50205 Onzole Formation Panama ......... 5, 6, 8, 19, 24-26, 36, 55, 61-63, PanamalPaleontolosy rojectesy. rene) eecie)atchensenenee paradisclusa, Lepicythara ......... 53165,9; ileei2s apbcthes Supe hese AM eo nachos nee 8, 56-59, 64-66 Saeheiaiste oF. 50s SOs OU 2s Pinecrest beds 66, 67, 70 7, 16-18 66-68, 70 eS 5 27, 40, 41 36, 43-54 Savaneta Glauconitic Sandstone Member ............ 41, 42 Shark Hole Point Formation ...... 7, 8, 24, 25, 36, 55, 61-63 ShoaliRiver Formationy =. cu-vue + <1 enciere ch emen steerer 7, 13-16 Spi Asnepicythara aaa -neicrcie ts oro chee oan 6, 8, 11, 12, 68, 69 SpiByMepicythara tem snemee tea nou sgt por ey mares 6,°8, 115 127568 SpicC -Lepicythara evasive ok tet ots ates -here se) ae 6, 8, 11, 12, 70 Sp; Diplepicytharat es yarns as sche ros een eye Re 6; 1 270 Sp PE epicy thang. siexeusushes soraceos isl seen 6; 1, 1257.0 Springvale Formatloniasrr «erst ter) <1 cia eens 7, 8, 27-29, 41 terminula, Lepicythara ........... 5, 6, 8, 11, 12, 52, 54-60 AN evoyreloyatels Ietoyqnvelalojn) Gino anoodddnhecooocasouesos bac 8, 39 toroensis, Lepicythara 5, 6, 8, 11, 12, 27, 36, 55, 59, 61, 62, 65 Meimidads 2 ssc. o 46k a evils of ce) line) aco vps ts bat chek Dy) Osmeai males MuiraYFormation) css fo @ oem Siete eas = bic eke eee eee 8, 68 Pid IE Monitelgeh @s eam cosa Bo e.d cl 6, 8, 11, 12, 64-66, 68 turrita, Lepicytharazatt: Senet 20) -)- eis els 6, 8, 11, 12, 65-67 WENEZUC]ahg: ee ieee yer toreesn ages neko tke ies pales ames 9-11 JETACTUZANG, ILEDICYIRATG. ya aeeae melts akots on ety an ea 72 PREPARATION OF MANUSCRIPTS Bulletins of American Paleontology usually comprises two or more sep- arate papers in two volumes each year. 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Printed in the United States of America Allen Press, Inc. Lawrence, KS 66044 U.S.A. CONTENTS Page NDS 4 Sol dn oo Goose onde oun Od ue UdopEtiode cond 066 0 cljjac.n ooo om obo Soi oo OIRO Coach ioe DE tO ea ecos oto Dats ic 5) IiRBHO 6 6 oc utmd oS caeo ud obs bone oe om DOS 6 oo Uo meow oqo wick MEDIO oN8)0 yo olceoetinsh cedece in ici ticsais DAO tue rc DCD 5 Prieosane Simitseeidiy coogeaegccdeos oe agen cS ce uonussaccm 606000 Damion aid colnreoS pic anion OID OCG: io nino iG Oicibi 7 PAO ONT Sc cu coco ceded aoa aS UBS MONE CO UR COD diwin a roto G o.oo Olomacios COI Ec ole OU IO Canmin aCe S RACE. O25 8 Compositionyandealeobiopeopraphy, vercyrer= cis ert eis benete tere semen suet ofan ies dials a lec alse ers ne afc! aye eles eo cls utc ils 11 QUGIMNAGT oc cd.0 due oe oe COUN) Orion me SE co mie 6G bGis 0/0" oxic oO ora EN 0 Genin pina pido eap lola co Da aibarsOr) icicle ec Sic ic 15 QysisimAite PALO) casmnocusoooupnaona coo mDodon Sa nach Gmmtidic. 41901 610 co ska cio UigiDroiO eit OrsIuI Cac IO oie 2 ai 16 Gags IDEN cols be betdeoeee eowdee pico eodbe bebo cope bape Dade Go am oUa mc Ooo Uae ciD Cr cuteipsOsD ort OOo pGwoerrer Oso 16 Oritee Wma Gupoe desc epoaunee deo on meh on 6 66.680 oa dg. olin O/oerarc.asSip ei ci0lb Orc Gof 1o, clmiclc Osne car Gho scr FORO gC aio cia c 16 JEATNINY INGMEGED a eon mane bo ee ome RED OO OO a8 > cri ne Gio b.0 © cbt akc ono pr oloeeeo: eyByo se Gattac oetrty oon eae iii eG 16 anni lygVi alll etic ac mepemenere se specter ae tee eens: 1 ester efor vob se atcsMcitey et =r Oh) b-day recta inkedfer-) eo -casict sev euasial ay nencae ing (t-aancirict 19 (Oye INGIONGE = saades oes se Gand eed 0 Ga monn SOmmnCs oo Sols 65 orld Sod a. bercim ios © oka chp lokg Ryo Usd acum care tase cicuCacaok Oth 20 RarmlyaGucullacidacssmyatacrrqecri-nseeienerer eureka ee -ieyeg es seep nen Nya tenon sme i2bey rtee) eyeet trols ne Netcare =e teas sn regeded cuca Sc 20 Oye ME 5 op copaegacansas ance au pond gman comets HOnipor ao ome OO DUO Omen oO Oo IURIa Kae Doras: 20 IIA, IMINGES. 6 o5 ago pipe alas o 465 glo Goo Vee ates cbr Gatos bale 0 Dicken mai. c ocho bug iii a pune tag oac)cika Fasc 20 t 20 (O}Ge IAGnOGEy coon Glsc6 opin coms a0 poe cOtndeee mpumoe Go.c's olpiy ckena.o U6 a Gcanicineo aim Onto DhOlo rancor creera Gg. crorckc Oso robot 20 iremilhy INGE. 5g occgandaubanqean oo a poMemUnMUe ceadmga npolom 2c ur mod Oldod Olovro anh cf atic Tetha-c.5 tid cao BiG 20 JS MIN OMICS oo odin op sua reomi oot uno OMG ob mmm UO e obi omnes poe dn Hogi noo ou ce oia cr aia Clb icin GTi Zl Oiler Veineiotk: 55 cede Gmos eno 6b 0 Oo clomiolg ute EU moro Braye rome 6bi0 Pcrd/d. oO acne 0B deb Oto. Gad oec IU CeD GOO Ich Cr Oh OM ria ti ceciec 21 TFT ILA CAGES. a jon ab 6 000 0 pups Re mmm neice OURO 6-0 O Ofte pros ig Ore. clo DiscrO eb Od G Biotic Sisco Digs taint 21 TEA; WW MESIGGES o5.6.5.6 gid ened an aoa ono Ume ON deuniy alone crcbedto G aic aicya Ci :Olo Tce ceo a eecigo, oo ALOE Reman DIDI 22 lsat y UA MINTIGEIS. oo mee plo ao Gd a bomiblo ond Oo crclnreee me eenOrOn nro min lb 516 ee cc ofa ms legs orc 0 ican ci GION ie ICh On 23 Reith? NENSEGES nine cade camo da ones o cole cla mowo eo a Rin ol Aird a cierd)as ocd Olgas ona gine Caan aeO ce oe 02O1c a 24 ORERIMNOGA oe aobaveadee osanmoonounU ao oom co Ome Uo UO 0 CONE pi Om cigar Helo Cr Omi igad cyrhc on aca ReCI ETD E 24 RAMI TACIIGES goo uaennosa eee pot enoos GMa ori a ma eemiG OAM OD Om lod Ge Gra o sini otent Ol Ostiey OisuesOIE ic 6D, Gic One: 24 Onl Mnaktloninochls ogee ego opeuston peo nbOaaGuns Moatoaa so oA SOR olad co Oga a gua dm im or alerein Om ano oui Cas ONae 24 jamilyaPeriplormatid ae cacy wewsesarsesse yest stein ane ecient en shee oer eel este ae et ested ecm oelyfc gs WauicNe Yo scicccheuenry hata ceed 24 Ghes Garin goagensdooosedduaades samo ce cna dGoMoUsese men mo oD Room a cmon on oom mmm og ou oui oC pO 25 Onise Awemeorrimpsruht; gonanwoeer ashe ancgop Gos uosE mes uo UDoon ao Oo dD UOId mim mao ee OG odo Dc Ona 25 Jah emioiomrinitcho Goon oe seE nooo o¢os dogo mmouemmamaacigo Ss CeO ona ne.cd ns opin Getto COmNG co dian exo Oi 25 OrdemPatellocastropodaleeew were uey suemeere le ets geerlen eplessga afer Voumone ta raulnear gat eMagsba chen suis c= fey =) shia) afeorie)sedcitenrse imasic sara is 26 lstnnihy NeW oo bopoe da Guna co UdopHO SUD DUG OmM AHO Snn COU GOD OD pO OUND gon romano Cumb od COD a oO 2c ce 26 Oncor Chanopesieostt sogugeoomeces sachs ood Udoe edad be mb e aa Ob co Rol erode ao toe) DID IONO!o oe aay 2 lem Ganiniehs “eo enoneadananathecose ses amber mnon bp obosc ecco mroe GObmnn one me 0G DU amma cain 27 iseinotihy IitemGHY Ganaogeoecomeaouneunboomaoco Eno dee Ucn ccinmbon 6 Gomi or ot oo aU SBI Oma aint DIAG CS 28 lsatihy AyoeiniiGS Gop goapondnusdcdse coe mo bod ao oam pen moo be pom Hecho mG cle cicsd om DiniCiuema co uG pO Pac 30 ley SininOLnGhs 6 oaagcouddas uboe e006 capi ca cicemmmn Scions 5 G01 nie oi aitap Edi SIO cg -bio Oc Occ iiel a aaratr 31 Inada? VAI Zone ac ocnunedg on aud ou bos duro como man cds Gobo Odeo om WO. aD tO-CaninI oo bio dC Ot eraaG Eau nnipi Hy 33 jk NEGOGHS Gaareas nc saoee aaueoe nooo eas Donne nom ou cod ci neo cbr dim 0 oo bi O me mipio iio Re eA PeoiOr a 33 lseinmhy leeINSNNGES sy eo gud asc Se dee hones epasoen coder ede toes Pod co odin ibaa mm. 0 0 to 0 Dien ys-5 caDicidio mir Q rid tu 35 letienihy MIE 5 cpnagossctusaDneon Dome eno bEMn ODE Omoou od od dudm cle ha d:c.o tio bisa cb)o Cac asus Ole orc. 36 [RAMI TMGKINGED oelogodbobonecsoueceoe apapbun MHU mor ou samatN Too ORn acme OG COD mC tr rE OED oie Oc 37 linnhy NESIGED. 5 oeopoanse och eon Oeeu Hone DMO CGO SME GOO EHO COM e 00.5 00 Cima dont Bylo CrR mG m0 o> Olcr ion 38 [Raby FEGSOIHIGES, Aca gn aolcin mew nib bin o Dold Ome am olbimo cmd onic i olp Ooi. o pla tira eiicen Grr tect Cad ina ceoe rior eRIaG 45 iReratihy WONGUEO ecpodeebenios OpMoo ooo aD Com MomD EDO bobo Ubu gape cigoommcrO pid cine Ubi Odo tiS oi DONS c 47 [RMI IM OeGES. Gonmensaducd dod ue pon SsmoUe mad omen ome 7b o0-oO cco os cao G0 Cima cx Din ini Orb Olds 47 On SisilomeiopliOn .sotnacencdengoens sooouomuoMmpOs EH eA mo ence obo oy COG E Oem U Demon 0 GCL i0 ao DD 48 IMIhZ NMOS coe goonnaqdeduas san be ob dmio on oOo os.s ob Deo o Ur em eid oo /Uic Diam eb G10 cam CNei iE C: Oct CIO to1E 48 Onis Geimlognti Geaonauesaavachecssoouad opens Namo do oom ane G acur mas amr oiclol b koe uksmoic clo ren r OSH 51 Sei) CU nihGke so ocomeconecnHPenbobore Gea Oeo oC One H COBOURG OOO Dao PB Ome OME Orc DbIOS 2 iDaGn Ort ct 51 Appendix: Maastrichtian/Danian Seymour Island Data Base, by William J. Thi GulsKergaouedooucgene see so So aa costs com ts o 51 AGMMAMEAMINS coocvdenodencs 66 bdo sete docaroamane goes 650 bem Ooo pia nmmc sie pica. Opi DoT RAD imi-C tac) n Oe 64 References! Gited) # weer cere eins c ioeiestereas sens ba ouhiere eee. Oe Oil oh Ota nO: OCU EAE EE RUMEN ONG Ole peanter HOE tact own Ione IO Capron Rea 65 PINGS odasodcotizs ue mouonoon pale bond cdo clo oC asub om ae Sino ooo iG Gp 0 e.cip kiGiO shoseleecsois cero 5) OecaC RGR Cat C a CGA 73 4 BULLETIN 367 LIST OF ILLUSTRATIONS Text-figure Page 1. Index map showing Seymour Island off the northeast tip of the Antarctic Peninsula .............. 02.0. e eee eee eee eee 6 2. Distribution of latest Maastrichtian and Danian mollusks between 900 m and 1200 m of the Lopez de Bertodano and Sobral formations De iaea a Wau tes, a4 cue ws bo ayeeenebens Wega Oleh tpenn. ol t/a) Mo auecernds aro Gir tusPetehs Gus MepoL a ciremecre ar alses, * emer) G),o eae eae 8 3. Stratigraphic distribution and feeding strategies of Danian bivalves from the Lopez de Bertodano and Sobral formations, with inferred InN re Gono Go dobbs oso GOs 0 blo 46 UdUt CUMOT OO UOy Ss UCC MAG UeoOOn OOOO Uan EO boo MOoob Uno oe 9 4. Stratigraphic distribution and feeding strategies of Paleocene gastropods from the Lopez de Bertodano and Sobral formations ... . . 10 S.estratigrapbhicsplane-analysispprojeCuOmSe tay pete eis yey cvielteatiemoae a ietiouaienst ies iianeertot = eolgettsvie usikodicli-talfotisyielictie caietic tr xetial oa. keith Weht stage eee eer 52 6.) Determinationiofirelativeystratisraphic Occurrence... iste melas ocyeMeneiedelo tele: ~ vodcmen= nel oueiietlsrie-volietsiteleltel i olicnce tells tokeltell i aan ae eee 52 7. Geometric relationship of stratigraphic plane with spatial occurrence of location data ............ 0.5.00 0 00 cee eee eee 52 8. Two-dimensional projections of Maastrichtian/Danian fossil localities on Seymour Island ... 2... 0.020202 0 ee 53 LIST OF TABLES Table Page 1. Systematic checklist of Paleocene bivalves from the Lopez de Bertodano and Sobral formations, with inferred life habits ........ 11 2. Systematic checklist of Paleocene gastropods from the Lopez de Bertodano and Sobral formations, with inferred life habits ..... . 12 3. Geographic and relative stratigraphic locations of Maastrichtian/Danian fossil localities from the Lopez de Bertodano and Sobral POLTMALLONS ee fons, 51S eecesha FER Bie PACED GEA eee She. eo oy cule sae sere etennbrre ete ents alas Gales: Ar PSR Ria Pie shope Pet oA ies Roptaten outete apart tts Rete h Ce ace aan ee eam 54 Ave Danianwlocality/SPEClESsTe OI SUL Yat pcos rene retake gate er ol ol na) ira oacors Meveoy fel agence icon 2) ay ievrettay esta tetietenite nes Man osNe] onto reste folteyias te eviee te ck keer teh schist aan Syl Se Danianspecies OCcuIreNncevand abUNGANCEME SIS HEY” yey reyr=eyct apts, wheres 12) eter let cits cote Doe Cee yeep ohiol is Ses fave scl- toute 'o) fet auel etteettoli st ett=yie fies ete ea eee 6l EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: SYSTEMATICS, PALEOECOLOGY AND PALEOBIOGEOGRAPHIC SIGNIFICANCE JEFFREY D. STILWELL!2, WILLIAM J. ZINSMEISTER*, AND ANTON E. OLEINIK?* 'School of Geosciences, Monash University, Clayton [Melbourne] VIC 3800, Australia Centre for Evolutionary Research, Australian Museum, 6 College Street, Sydney, NSW 2000, Australia E-mail: Jeffrey.Stilwell @sci.monash.edu.au 3Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, IN 47907 U. S. A. E-mail: wjzins @ purdue.edu ‘Department of Geography and Geology, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991 U. S. A. E-mail: aoleinik@fau.edu ABSTRACT The Paleocene (Danian) molluscan fauna of the Lépez de Bertodano and Sobral formations of Seymour Island, Antarctic Peninsula, is the only shelf fauna of this age from the continent of Antarctica and provides the critical insight into the emergence of marine faunas of the Southern Hemisphere following the mass extinction at the end of the Cretaceous. The Danian molluscan fauna on Seymour Island consists of 58 species of which 40 are new. Bivalves are represented by 20 species from the Lopez de Bertodano Formation unit 10 and the Sobral Formation. Newly recognized taxa in the Antarctic Danian include: Nucula sp., Nuculana antarctirostrata n. sp., Ledina? sp., Jupiteria? sp., Saxolucina antarctipleura n. sp., Thyasira austrosulca n. sp. and Periploma? sp. The gastropod component of the Danian molluscan fauna of Antarctica is by far the most diverse, with 37 species recorded, of which the following 30 are newly described: Conotomaria sp. A, Conotomaria sp. B, Conotomaria sp. C, Acmaea submesidia n. sp., Bittium (Bittiwn?) paleonotum n. sp., Bittium (Zebittium?) brooksi n. sp., Turritella (Haustator?) parisi n. sp., Mesalia virginiae n. sp., Struthiochenopus hurleyi n. sp., Antarctodarwinella austerocallosa n. sp., Amauropsis notoleptos Nn. sp.. Euspira antarctidia n. sp., Antarctiranella tessela n. gen. n. sp., Melanella seymourensis n. sp., Heteroterma? n. sp., Pyropsis? australis n. sp., Colus delrioae n. sp., Pseudofax? paucus n. sp., Levifusus woolfei n. sp., Probuccinum palaiocostatum n. sp., Serrifusus binodosum n. sp., Sycostoma pyrinota n. sp., Strepsidura? polaris n. sp., Paleopsephaea? nodoprosta n. sp., Taioma sobrali n. sp.. Zygomelon apheles n. sp., Mitra (Ewmitra?) antarctmella n. sp., Marshallaria variegata n. sp., Cosmasyrinx (Tholitoma) antarctigera n. sp., and Cylichnania? cf. C. impar Finlay and Marwick, 1937. These gastropods occupied various niches in temperate shallow shelf environments and are represented by only a few individuals at any given locality. The Danian gastropod fauna of Seymour Island is dominated by carnivores (c. 60%) with epifaunal grazers (c. 17%), deposit feeders (c. 13%), epifaunal browsers (c. 7%), and a single ectoparasite (c. 3%) composing the remainder of the fauna. The fauna extends the geologic range of many groups with several crossing the K-T boundary extinction event. Species-level survivorship is relatively high at 39%. Five gastropod genera (Antarctodarwinella, Antarctiranella n. gen., Probuccinum, Sey- mourosphaera, and Struthiochenopus) are endemic to Seymour Island. All species reported from the Danian of Seymour Island are endemic, pointing to a strong degree of provincialism and isolation of the fauna from coeval forms in the Southern Hemi- sphere. These new data suggest that the molluscan faunas of Antarctica belonged to a distinct biotic province by Danian time. INTRODUCTION Paleocene molluscan faunas are rare in the Southern Hemisphere fossil record, and those from the earliest Paleocene (early Danian) are particularly important, in that they provide data on the early biotic recovery and repopulation phase following the Cretaceous-Tertiary (K-T) boundary extinction event. Paleocene faunas are characterized by complex evolutionary histories fol- lowing the end-Cretaceous event. The survivors of the K-T event and also the appearance of new groups and migrants in the Danian not only herald the beginnings of the modern biota, but further mark the initial re- covery and radiation phase immediately following the extinction interval. Few diverse Paleocene molluscan faunas have been recorded in the Southern Hemi- sphere, and of these faunas, the shallow-marine suc- cession on Seymour Island, Antarctic Peninsula (Text- fig. 1) represents the only well-preserved molluscan record across the K-T interval and into the early Pa- leocene (Danian). The Seymour Island sequence pre- serves an important record of the composition of Dan- ian Mollusca, which is providing exciting new data on the extent of the extinction event in the high southern latitudes and also the complex processes of biotic re- covery. These records document changing environ- mental conditions relating to the final breakup of Gondwana, lowering sea-surface temperatures, the K/T extinction event, and the refilling of vacant eco- space with opportunistic and migrant groups of mol- 6 BULLETIN 367 Lopez de Bertodano Bay Cape Wiman Surficial deposits ie) Telm6-7 La Meseta Telm &-5 Formation Telm3 Telm1-2 Penguin aC Bay ross Valley Mbr. Sobral Tpst Ips? Formation ps3 Tps3 sad Ips)-2 Penguin KTIb 10 Lopez de Kib1-9 Bertodano Formation pms Text-figure 1.—Index map showing Seymour Island located on the northeast tip of the Antarctic Peninsula. lusks following the impact event at the end of the Cre- taceous. Most previous work on Antarctic Paleogene mol- lusks has focused on the highly diverse Eocene assem- blages of the La Meseta Formation of Seymour and Cockburn islands (see Wilckens, 1911; Zinsmeister, 1984; Stilwell and Zinsmeister, 1992; Stilwell and Ga- Zdzicki, 1998; Stilwell, 2003a) and those taxa recov- ered from Eocene erratics of the McMurdo Sound re- gion of East Antarctica (Stilwell, 2000; Stilwell and Zinsmeister, 2000). Stilwell and Zinsmeister (1992) recognized 170 species of Eocene Antarctic mollusks, collected from a spectrum of environmental settings spanning barrier islands to nearshore tidal and wave- dominated environments. At least 10 species remain undescribed (JDS, personal observation). Stilwell (2000) recently described 65 species from McMurdo Sound glacial deposits in nearshore shelf settings and facies. Of these, at least 22 species of mollusks, a sin- gle brachiopod, and a shark were found to be common to both the Antarctic Peninsula and East Antarctica. The discovery of a significant number of taxa common to both regions indicates unequivocal marine links dur- ing the Eocene and circum-Antarctic circulation (Stil- well and Zinsmeister, 2000). These authors concluded that the East Antarctic sea-surface temperatures during the Eocene may have been temperate, based on the composition of characteristic warmer water taxa and the marked percentages of characteristic Indo-Pacific/ Tethyan and cosmopolitan genera and subgenera in the fauna. Further, approximately 11% of the 136 mollusk genera and subgenera and all of the species recorded from the Eocene of Antarctica are endemic, indicating that the continent belonged to a distinct biotic province by this time. The strong endemicity of the fauna sug- gests that the isolation of Antarctica commenced by the early Paleocene. To date four taxonomic papers have been published on Antarctic Paleocene mollusks; these include a sca- phopod Eodentalium grandis Medina and del Valle, 1985, from the Sobral Formation; bivalves from the Lopez de Bertodano and Sobral formations (Zinsmeis- ter and Macellari, 1988); one species of aporrhaid gas- tropod, Struthiochenopus hurleyi n. sp. (= S. norden- skjoldi (Wilckens, 1910)), originally thought to be re- stricted to the latest Cretaceous but now known to span the K-T boundary into the Danian interval on Seymour Island (Zinsmeister and Griffin, 1995); and a new ge- nus of probable pseudolivine gastropod, Seymouros- phaera, represented by four species (Oleinik and Zins- meister, 1996) in the Danian. These studies reveal that a rich, shallow-marine fauna existed during the early Paleocene along the Antarctic Peninsula. This research not only provides additional insight into the immediate post K-T boundary radiation of marine mollusks in Antarctica and globally, but further, yields exceptional EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. iT. new data on the patterns of biotic recovery of post K- T extinction faunas in the high southern latitudes. PALEOCENE STRATIGRAPHY Seymour Island contains the most complete, well- exposed section of Upper Cretaceous to lower Tertiary rocks in the Southern Hemisphere and is composed of highly fossiliferous marine sandstones and siltstones reflecting a spectrum of environments along the shal- low- to mid-shelf. The sequence is exposed over the southern two-thirds of the island, an area of approxi- mately 70 km?*. The extensive exposures of these rocks include one of the best K-T boundary sections in the world, which is providing an important opportunity to examine in detail the events at the close of the Cre- taceous, not only in a temporal context, but spatially as well (see Zinsmeister, 1998a). Upper Cretaceous and lower Paleocene strata on Seymour Island consist of approximately 1600 m of homoclinal, gently eastward-dipping, mid-shelf clastic to inner shelf concretionary siltstones and silty sand- stones, comprising strata of gray to tan fine-grained sandstone and sandy siltstone of the Lopez de Berto- dano and Sobral formations (Zinsmeister, 1998a). The Lopez de Bertodano Formation ranges in age from late Maastrichtian to Danian, and the Sobral Formation is of Danian age. Faunal diversity is relatively high with an admirable record of mollusks, corals, brachiopods, annelids, decapods, echinoderms, and marine reptiles. Substantial tree fragments up to | m in diameter are abundant at various levels in the succession. Sedimen- tological evidence, such as extensive bioturbation in the strata and the absence of primary sedimentological structures, suggests that deposition was, in all likeli- hood, mid-shelf below effective wave base (Macellari and Zinsmeister, 1983; Macellari, 1988; Oleinik and Zinsmeister, 1996). The K-T boundary interval is located at the base of a glauconitic unit referred to as the ““K-T Glauconite”’ and crops out in a snake-like pattern along strike for approximately 7 km forming a belt about 2 km wide. No K-T boundary section in the Northern or elsewhere in the Southern Hemisphere has aerial exposures that approach those on Seymour Island. The K-T Glauco- nite consists of three lithologic units: Lower Glauco- nite with iridium anomaly (O—1.5 m), Fish Bone Layer (2-3 m), and Upper Glauconite (O—0.1 m) (Zinsmeis- ter, 1998a). Precise dating of events through the ex- tinction-survival-recovery interval on Seymour Island is limited by the absence of calcareous nannoplankton and planktic foraminifera in some horizons. Work by Huber (1988) suggested that the last Cre- taceous planktic foraminifera are recovered from an interval 1 to 4 m below the glauconite bed and that the first Danian species of planktic forms are recog- nized | m below the contact between the Lopez de Bertodano and Sobral formations approximately 45 m above the K-T boundary. This places the contact be- tween these formations with the API Foraminiferal Zone. Huber (1988) referred to this gap in the presence of planktic microfossils as the “‘dissolution’’ zone re- sulting from the perturbation of the sea chemistry fol- lowing the K-T boundary event. The ubiquitous pres- ence of well-preserved macrofossil assemblages throughout the K-T boundary section indicates that whatever processes dictated the presence or preserva- tion of calcareous plankton did not affect calcareous macrofossils such as mollusks. The K-T boundary is pinned to the Lower Glauconite based on the presence of the iridium anomaly at the base of the ““K-T Glau- conite” (Elliot et al., 1994). The extinction-survival- recovery phases succeeding the boundary event on Seymour Island span the approximately 90-m interval of Unit 10 of the Lopez de Bertodano Formation and the lower two units of the Sobral Formation (see Text- fig. 3). Analysis of the geological range data of species re- covered from the K-T boundary interval on Seymour Island (Text-fig. 2) reveals that at least 20 species (55%) disappeared through a 16-m interval below the K-T boundary (Zinsmeister, 1998a). Two extinction steps occur 1.5 m and 1 m below the Lower Glauco- nite. Two species (6%) last occur in the “K-T Glau- conite’” and 14 (39%) Maastrichtian species pass through the boundary event into the Danian. The Low- er Glauconite is interpreted to represent the boundary event with the extinction interval commencing | m below, following the study by Kauffman and Harries (1996) on biotic recovery. The survival interval is rep- resented in the Fish Bone Layer and the recovery in- terval occurs in the Upper Glauconite. Some 11 spe- cies of mollusks are present in the ““K-T Glauconite,” 6 species in the Lower Glauconite, 6 in the Fish Layer and 8 in the Upper Glauconite (WJZ and JDS). Only two species, bivalves Panopea clausa and Seymour- tula antarctica, become extinct within this interval. These bivalves were probably suspension feeders, which were especially hard hit during the K-T bound- ary event with the significant reduction in primary pro- duction at the boundary (Rhodes and Thayer, 1991; Hansen et al., 1993; Sheehan er al., 1996). The Fish Bone Layer (see Zinsmeister, 1998a) is believed to represent the “‘crisis zone’ immediately following the boundary event. The significant occurrence of fish de- bris over an interval of ~2 to 3 m indicates multiple local kill events, which suggests that the Fish Bone Layer represents an interval of unstable conditions fol- lowing the extinction event. 8 BULLETIN 367 1200 — Opportunistic— sled Floods ~~ _| 64.981 ma 1150 Pe aeeeaane | Bone Horizon 1100 10650 1000 960 300 123.4 5 6 7 8 9 101112131415 1617 18192021 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39.40 41424344 45 46 47 48 4950515253 54 55 56 57 585960616263 64 65 66 67 68 69 Text-figure 2.—Distribution of latest Maastrichtian and Danian mollusks between 900 m and 1200 m of the Lopez de Bertodano and Sobral formations. Data obtained from 327 localities from ~70 km? on the southern two thirds of the island in addition to 25 limited measured sections (see Zinsmeister (1998a) for discussion of data from these limited measured sections). Stratigraphic occurrence of each taxon was determined using Stratigraphic Plane analysis (Zinsmeister, 2001). Dates highlighted in figure were determined by McArthur er al. (1998). The expanded box shows the K/T boundary (1054 m); Fish Bone Layer; first appearance of opportunistic Lahillia larseni and Struthiochenopus hurleyi floods (64.981 ma); A, first appearance of crisis progenitor species Struthiochenopus hurleyi, B, first appearance of northern refugia species (Seymourosphaera spp.) from Southern South America and cosmopolitan immigrants; C, first occurrence of western refugia immigrant species (Antarctodarwinella austerocallosa n. sp.); and D, diversity of Danian molluscan assemblage reaches pre-extinction diversity (64.701 ma). Ages of opportunistic floods and diversity based on strontium isotope profile (McArthur er al., 1998). Taxa in figure—l. Entolium seymourensis, 2. Nekewis n. sp.; 3. Nordenskjoldea nordenskjoldi; 4. Austrocucullaea oliveroi, 5. Pulvinites antarcticus; 6. Dozyia dryalskiana; “Buccinum” n. sp. A; 8. Modiolus pontotocensis; 9. Thyasira towsendi; 10. Lucina scotti 11. Solemya rossiana; 12. Seymourtula antarctica; 13. Vanikoropsis n. sp.; 14. Buccinum n. sp. B; 15. Pycnodonte seymourensis; 16. Anagaudryceras seymourensis; 17. Perotrochus larseniana; 2. Pseudophyllites loryi;, 23. Zelandites varuna, 24. Diplomoceras maximum, 25. Austroaporrhais larsent; 26. Kitchinites laurae, 27. Taioma paviasela 28. Grossouverites gem- “Cassidaria” mirabilis; 18. “Fusus” philippiana; 19. Pachydiscus ultimus, 20. Eselaevitrigonia regina; 21. Amauropsis n. sp.; 2 matus; 29. Goniomya pens 30. Pyenodonte vesiculosa; 31. Cucullaea antarctica; 32. Amberleya spinigera; 33. 34. Oistotrigonia pygocelium; 35. Cimomia sp.; 36. Maorites densicostatus, 37. Cyclorisma chaneyi, 38. Panopea clausa; 39. Pinna freneixae; 40. Lahillia larseni; 41. Vanikoropsis arktowskiana; 42. Mesalia virginiae n. sp.; 43. Acesta webbi; 44. Cosmasyrinx (Tholitoma) antarctigera n. sp.; 45. Cucullaea ellioti, 46. Nucula (Leionucula) suboblonga, 47. Marwickia woodburnei; 48. Struthiochenopus hurleyi; 49. Ostrea sp.; 50. Seymourosphaera elevata, 51. Seymourosphaera bulloides, 52. Seymourosphaera subglobosa;, 53. Euspira antarctidia n. sp.; 54. Acmaea 58. Conotomaria sp. B; 59. Conotomaria sp. C; 60. Saxolucina antarctipleura n. sp.; 61. Antarctodarwinella austerocallosa n. sp., 62. Periploma? sp.; 63. Seymouros- phaera depressa, 64. Levifusus woolfei n. sp., 65. Pseudofax? paucus n. sp.; 66. Colus delrioae n. sp.; 67. Sycostoma pyrinota n. sp.; 68. submesidia n. sp.: 55. Bittium (Bittium?) paleonotum n. sp.; 56. Australoneilo casei; 57. Conotomaria sp A. Thyasira austrosulca n. sp.; 69. Nuculana antarctirostrata n. sp. Stratigraphic ranges based on regional dip of 7.4°. The contact between the Lopez de Bertodano unit 10 and the Sobral Formation is marked by a discon- tinuity. The relief along the discontinuity may be as much as 50 m. Phosphatic nodules, many with fossil cores and corroded concretions, occur along the dis- continuity. The discontinuity appears to represent a short period of scouring along storm weather wave base which may have been associated with the first drop in sea level during the earliest Danian. The ab- sence of any significant changes in the composition in the benthic fauna suggests that the disconformity does not represent a significant gap in time within the se- quence. PALEOECOLOGY Little has been published on the paleoecology of Ter- tiary Antarctic bivalves, apart from a few works dealing with life habits and environmental settings of Eocene mollusks of the La Meseta Formation of Seymour and Cockburn islands, Antarctic Peninsula, and McMurdo Sound, East Antarctica (Stilwell and Zinsmeister, 1992; Stilwell, 2000); and also Pliocene deposits (Jonkers, 1998a, b, 1999). These assemblages of mollusks were derived from a spectrum of environments along the up- per shelf ranging from beach to tidal-dominated near- shore facies. Paleocene mollusks of Antarctica lived in temperate sandy, shallow- to middle-shelf environ- EARLY PALEOCENE MOLLUSKS OF 1400 1350 1300 1250 1200 1150 1100 1050 1000 leo UNO 4s oie 1G) | ir 8 ANTARCTICA: STILWELL et al. 9 (Om tte 12) 13 9145 15> 161" 17 18" 9 Text-figure 3.—Stratigraphic distribution and feeding strategies of Danian bivalves from the Lopez de Bertodano and Sobral formations, with inferred life habits. Symbols: open square, suspension feeders; solid square, infaunal byssate; cross, epifaunal sessile; solid diamond, deposit feeder; open triangle, shallow infaunal. Acronyms: SE, suspension feeder; DI, deep infaunal; IB, infaunal byssate; SI, shallow infaunal; ES, epifaunal sessile; DE deposit feeder. 1, Panopea clausa (SF-DI); 2, Pinna freneixae (SF-IB); 3, Lahillia larseni (SF-SI); 4, Acesta webbi, (SF-ES); 5, Nucula (Leionucula) suboblonga (DF-SI); 6, Cucullaea ellioti (SF-S1); 7, Marwickia woodburnei (SF-SI); 8, Saxolucina antarc- tipleura n. sp. (SF-SI); 9, Ostrea sp. (SF-ES); 10, Jupiteria? n. sp. (DF-SI); 11, Ledina? n. sp. (DF-SI); 12, Nucula (Leionucula) hunickeni (DF-IS); 13, Periploma? n. sp. (SF-DI); 14, Thyasira austrosulca n. sp. (SF-SI); 15, Nucula sp. (DF-SI); 16, Australoneilo gracilis (DF-SD; 17, Lahillia huberi (SF-S1); 18, Australoneilo casei (DF-S1); 19, Nuculana antarctirostrata n. sp. (DF-SI). ments. See Text-figures 3 and 4 for the stratigraphic distribution of primary feeding strategies for the Danian bivalves and gastropods from the Lopez de Bertodano unit 10 and the Sobral Formation. The Paleocene gastropods from the upper units of the Lopez de Bertodano Formation and the Sobral For- mation were derived from predominantly sandy, shal- low- to middle-shelf environments in temperate coastal waters of normal salinity. Mollusks generally occur in isolated local shell concentrations throughout the Dan- ian part of the sequence, the only exception being the floods of opportunistic species, chiefly Lahillia larseni and Struthiochenopus hurleyi n. sp. immediately above the K-T Glauconite at the base of unit 10. In descending order of species-level diversity and importance, suspension feeders dominate the bivalve fauna with 55% of the assemblage belonging to this category, followed by 45% of deposit feeders. Most of the suspension feeders are shallow infaunal forms at- tributed to the Cucullaeidae, Lucinidae, Thyasiridae, Cardiidae, Veneridae, and Periplomatidae (see Table 1). The diversity and abundance of epifaunal bivalves are surprisingly rare during the Danian. The occur- rence of an undescribed species of Ostrea is restricted to the individuals associated with small biohermal con- centrations of branching corals that are limited to im- mediately above the disconformity between unit 10 and the Sobral Formation. Epibyssate suspension feed- ers are rare and include the rare species, Acesta webbi Zinsmeister and Macellari, 1988 (Limidae). Equally uncommon are byssate representatives such as Pinna freneixae Zinsmeister and Macellari, 1988, and Sey- mourtula antartica (Wilckens, 1910). Deposit feeders are members of Nuculidae, Nuculanidae and Mallet- tiidae, and are infaunal burrowers. This is consistent with the idea that epifaunal suspension feeders were particularly affected by the phytoplankton crash or the significant drop in primary production at the K-T boundary, leading to the demise of many suspension- feeding groups, compared with deposit feeders (see Rhodes and Thayer, 1991; Hansen er al., 1993; Shee- han et al., 1996). In the Southern Hemisphere, this pattern of selective extinction is corroborated in the K- BULLETIN 367 1400 1350 1300 1100 + +: ~ > $2 + 2 ¥ + . 2 2 {000 | SA che Nice ser Nia, 2) Al) 12/13 1S: 16 17 18) 19!) 20! 21 220 23° 24 25 26. 27 28°29! Sul si seas Text-figure 4.—Stratigraphic distribution and feeding strategies of Paleocene gastropods from the Lopez de Bertodano and Sobral formations. Symbols (and acronyms): open square, carnivore (C); open diamond, deposit feeder (DF); open triangle, epifaunal grazer (G); solid circle, ectoparasite (EP). 1, Vanikoropsis arktowskiana (Wilckens, 1910) (C); 2, Struthiochenopus hurleyi n. sp. (DF); 3, Conotomaria n. sp. C (EG); 4, Amauropsis notoleptos n. sp. (C); 5, Mesalia virginiae n. sp. (DF); 6, Seymourosphaera bulloides Oleinik & Zinsmeister, 1996 (C); 7, Acmaea submesidia n. sp. (EG); 8, Turritella (Haustator?) parisi n. sp. (DF); 9, Seymourosphaera elevata Oleinik & Zinsmeister, 1996, (C); 10, Cosmasyrinx (Tholitoma) antarctigera n. sp. (C); 11, Cylichnania cf. C. impar Finlay and Marwick, 1937, (C); 12, Euspira antarctidia n. sp. (C); 13, Melanella seymourensis n. sp. (EG); 14, Bittium (Zebittium) brooksi n. sp. (EG); 15, Bittium (Bittium?) paleonotum n. sp. (EG); 16, Conotomaria sp. A (EG); 17, Taioma sobrali n. sp. (C); 18, Marshallaria variegata n. sp. (C); 19, Antarctiranella tessela n. gen. n. sp. (C); 20, Levifusus woolfei n. sp. (C); 21, Seymourosphaera subglobosa Oleinik & Zinsmeister, 1996, (C); 22, Zygomelon apheles n. sp. (C); 23, Paleopsephaea? nodoprosta n. sp. (C); 24, Probuccinum palaiocostatum n. sp. (C); 25, Serrifusus binodosum n. sp. (C); 26, Colus delrioae n. sp. (C); 27, Pseudofax? paucus n. sp. (C); 28, Antarctodarwinella austerocallosa n. sp. (EG); 29, Conotomaria sp. B (EG); 30, Seymou- rosphaera depressa Oleinik & Zinsmeister, 1996 (C); 31, Sycostoma pyrinota n. sp. (C); 32, Heteroterma? n. sp. (C); 33, Pyropsis? australis? n. sp. (C). 11 14 T boundary and early Paleocene molluscan faunas of Antarctica and also New Zealand (see Stilwell, 1994). No bivalves are particularly abundant at any locality apart from a flood of the presumed opportunistic bi- valve Lahillia larseni (Sharman and Newton, 1897) in the early Danian. Lahillia larseni extends in the strati- graphic record from the late Maastrichtian across the K-T boundary into the Danian on Seymour Island, and although it is a relatively common member of the Maastrichtian benthic community, the bivalve is usu- ally represented by fewer than five individuals at any given locality. In the Upper Glauconite on Seymour Island, L. larseni is locally abundant, occurring in floods of thousands of individuals. Although the num- ber of individuals of L. /arseni decreases dramatically above the Upper Glauconite, the species continues to be a prominent member of the Danian benthic com- munity remaining. Only general comments about the Antarctic bivalve community can be made here, as it is a rather depauperate assemblage of only 18 species, and most of these species are generally represented by a few specimens of variable preservation. The number of articulated specimens of these bivalves is relatively high, suggesting that the environments in which they lived were below fair-weather wave base. Indeed, the absence of shallow-water sedimentary structures in EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 11 Table 1.—Systematic checklist of Paleocene bivalves from the L6pez de Bertodano and Sobral formations, Seymour Island, Ant- arctic Peninsula, with inferred life habits. Identifications by J. D. Stilwell and W. J. Zinsmeister. Acronyms used: DF, deposit feeder; IB, infaunal byssate; SF, suspension feeder; NS/, nonsiphonate in- faunal; BY, byssate: EB, epifaunal byssate; S/, siphonate infaunal. Inferred Life Bivalvia Habits Nuculidae Nucula sp. DF-IB Nucula (Leionucula) suboblonga (Wilckens, 1905) = DF-IB Nucula (Leionucula) hunickeni Zinsmeister and Macellari, 1988 DF-IB Nuculanidae Nuculana antarctirostrata n. sp. DF-IB Ledina? sp. DF-IB Jupiteria? sp. DF-IB Malletiidae Australoneilo gracilis (Wilckens, 1905) DF-IB Australoneilo casei Zinsmeister and Macellari, 1988 DF-IB Cucullaeidae Cucullaea ellioti Zinsmeister and Macellari, 1988 — SF-NSI Pinnidae Pinna freneixae Zinsmeister and Macellari, 1988 SF-NSI-BY Limidae Acesta webbi Zinsmeister and Macellari, 1988 SF-EB Seymourtula antarctica (Wilckens, 1910) SF-EB Ostreidae Ostrea sp. SF-ES Lucinidae Saxolucina antarctipleura n. sp. SF-SI Thyasiridae Thyasira austrosulca n. sp. SF-SI Cardiidae Lahillia larseni (Sharman and Newton, 1897) SF-SI Lahillia huberi Zinsmeister and Macellari, 1988 SF-SI Veneridae Marwickia woodburnei Zinsmeister and Macellari, 1988 SF-SI Panopea clausa Wilckens, 1910 SF-SI Cyclorisma chaneyi Zinsmeister and Macellari, 1988 SF-SI Periplomatidae Periploma? n. sp. SF-SI Unit 10 of the Lopez de Bertodano Formation and the Sobral Formation corroborates this observation. The Paleocene gastropods from the Lopez de Ber- todano and Sobral formations (Table 2) were derived from predominantly sandy, shallow- to middle-shelf environments in temperate coastal waters of normal salinity. In descending order of species-level diversity and importance, the gastropod fauna encompasses five general groupings: carnivores, epifaunal grazers, de- posit feeders, epifaunal browsers, and a single ecto- parasite. It is difficult to ascertain from the fossil re- cord if some of these taxa were predominantly epifau- nal or infaunal forms or at specific times during their life cycle could inhabit both realms (e.g., Naticidae, Cerithiidae, Struthiolariidae). The carnivores dominat- ed the Paleocene Antarctic shelf environments with just over 60% of recorded gastropod species belonging to this category. These families include the Naticidae, Tudiclidae, Buccinidae, Fasciolariidae, Volutidae, Mi- tridae, Turridae, and Cylichnidae. Most of these taxa are considered to be epifaunal mobile taxa, apart from the volutes and naticids, which could have been either infaunal or epifaunal comparable to Recent forms. Carnivores apparently dominated the immediate, post K-T boundary shelf environments, and were opportu- nistic, rapidly evolving species of so-called ““bloom families” (sensu Hansen, 1988) that flourished in Pa- leocene marine environments. Epifaunal grazers such as the pleurotomariids and the single acmaeid make up 17% of the gastropod fauna, although it is possible that some pleurotomariids were either unspecialized om- nivores or carnivores (see notes by Darragh and Ken- drick, 1994, p. 5). Deposit feeders were a significant element in the Antarctic Paleocene community, but still represent only about 7% of the total species-level diversity; these include members of the Aporrhaidae and Struthiolariidae. Epifaunal browsers that fed large- ly on detritus make up a small proportion of the fauna at only 7% and these include cerithiids of the Bittium group. Turritellids are largely suspension feeders (AII- mon, 1988), and make up about 6% of the species total. Melanella was in all likelihood an ectoparasite that lived on echinoderms, consistent with most living forms, and makes up the smallest category of Antarctic Paleocene gastropods at only 3% of the total. None of the recorded gastropods from the Lopez de Bertodano and Sobral formations are particularly abundant at any locality, except for Struthiochenopus hurleyi n. sp. and Bittium (Zebittium) brooksi n. sp. S. hurleyi n. sp be- comes locally abundant immediately above the upper glauconite horizon. Its abundance in association with the Lahillia floods suggests that it is one of the op- portunistic species which appear in great number fol- lowing the boundary event. Throughout the rest of the Lopez de Bertodano and Sobral formations S. hurley n. sp. is locally abundant. B. (Z.) brooksi forms local nearly monotypic concentrations at several localities in the lower 50 m with its first appearance in the Fish Bone Horizon. This overall rarity and rather low spe- cies-level diversity of gastropods attests to the signif- icant impact of the K-T boundary event and is a re- flection of the decimation and general low diversity of 12 BULLETIN 367 Table 2.—Systematic checklist of Paleocene gastropods from the Lopez de Bertodano and Sobral formations, Seymour Island, Ant- arctic Peninsula, with inferred life habits. Identifications by J.D. Stil- well and A.E. Oleinik. Acronyms used: DF, deposit feeder; SE sus- pension feeder; C, carnivore; EB, epifaunal browser; EG, epifaunal grazer; EP, ectoparasite; E/I, epifaunal/infaunal; EM, epifaunal mo- bile. Inferred Life Gastropoda Habits Pleurotomariidae Conotomaria sp. A EG-C? Conotomaria sp. B EG-C? Conotomaria sp. C EG-C? Acmaeidae Acmaea submesidia n. sp. EG Cerithiidae Bittium (Bittium?) paleonotum n. sp. E?B Bittium (Zebittium) brooksi n. sp. E?B Turritellidae Turritella (Haustator?) parisi n. sp. SF-E/I Mesalia virginiae n. sp. SF?-E/1? Aporrhaidae Struthiochenopus hurleyi n. sp. DF Struthiolariidae Antarctodarwinella austerocallosa n. sp. DF-E?/1? Vanikoridae Vanikoropsis arktowskiana (Wilckens, 1910) 1?/E?-C Naticidae Amauropsis notoleptos n. sp. C-E?/1? Euspira antarctidia n. sp. C-E?/I? Ranellidae Antarctiranella tessela n. gen. n. sp. C-EM Eulimidae Melanella seymourensis n. sp. EP Tudiclidae Heteroterma? n. sp. C-EM Pyropsis? australis n. sp. C-EM Buccinidae Colus delrioae n. sp. C-EM Pseudofax? paucus n. sp. C-EM Levifusus woolfei n. sp. C-EM Probuccinum palaiocostatum n. sp. C-EM Serrifusus binodosum n. sp. C-EM Sycostoma pyrinota n. sp. C-EM Seymourosphaera subglobosa Oleinik & Zinsmeister, 1996 C-EM Seymourosphaera depressa Oleinik & Zinsmeister, 1996 C-EM Seymourosphaera bulloides Oleinik & Zinsmeister, 1996 C-EM Seymourosphaera elevata Oleinik & Zinsmeister, 1996 C-EM Strepsidura? polaris n. sp. C-EM Fasciolariidae Paleopsephaea? nodoprosta n. sp. C-EM Taioma sobrali n. sp. C-EM Table 2.—Continued. Inferred Life Gastropoda Habits Volutidae Zygomelon apheles n. sp. C-EM Mitridae Mitra (Eumitra?) antarctmella n. sp. C-EM Turridae Marshallaria variegata n. sp. C-EM Cosmasyrinx (Tholitoma) antarctigera n. sp. C-EM Cylichnidae Cylichnania cf. C. impar Finlay and Marwick, 1937 1?-C invertebrate faunas during the earliest Danian resulting from the mass extinction. COMPOSITION AND PALEOBIOGEOGRA PHY Paleocene molluscan faunas are rare in the Southern Hemisphere, and earliest Paleocene faunas are partic- ularly so, and are represented solely by the early Dan- ian fauna of Seymour Island. This fauna is extremely important in that it not only fills a major gap in our knowledge of early Paleocene Austral molluscan fau- nas, but provides much new data on the steps of biotic recovery following the K-T boundary event. Other Austral Paleocene faunas have been thoroughly doc- umented and/or await further attention, but are either late early to late Paleocene in age or not particularly well dated; these include the late early to late Paleo- cene faunas of New Zealand (Finlay and Marwick, 1937; Stilwell, 1993, 1994; JDS, unpublished data), late Paleocene of Chatham Islands (Campbell ef al., 1993; Stilwell and Grebneff, 1996; Stilwell, 1997, 2003a; JDS, unpublished data.), mid- to late Paleocene of Victoria and Western Australia, (Singleton, 1943; Darragh, 1994, 1997; Stilwell, 2003b; JDS, personal observation), and poorly dated Paleocene faunas of southern South America, predominantly southern Ar- gentina (Olivero eft al., 1990; Camacho, 1992; Griffin and Hiinicken, 1994; JDS, personal observation). The Paleocene fauna of Antarctica provides important in- formation on the composition of immediate post K-T faunas during the early recovery phase following the mass extinction event. The Antarctic gastropod fauna records taxa that are either the oldest member of respective genera (e.g., Bittium (Zebittium), Antarctodarwinella, Amauropsis?, Melanella, Heteroterma?, Pseudofax?, Colus, Levifu- sus, Probuccinum, Strepsidura?, Zygomelon, Vexillum s.L., Marshallaria, Cosmasyrinx (Tholitoma), and Cy- lichnania) or some that survived the K-T event in the earliest Danian (e.g., Perotrochus, Conotomaria, Ac- EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 13 maea, Struthiochenopus, Vanikoropsis, Euspira, “*Pyr- opsis,” Serrifusus, Sycostoma, Paleopsephaea, and Taioma). Others are either members of widespread genera that may have evolved in the high southern latitudes or of uncertain origin, representing Indo-Pa- cific/Tethyan or Temperate forms (e.g., Perotrochus, Conotomaria, Amauropsis, Antarctiranella n. gen., Pyropsis?, Heteroterma?, Colus, Strepsidura?, Levi- fusus, Serrifusus, and Paleopsephaea). Some 34% of genera and subgenera make up this category. Only four genera, Antarctodarwinella, Antarctiranella n. gen., Probuccinum, and Seymourosphaera, are endem- ic to Antarctica, and compose between 12.5% and 16% of the total fauna. Antarctodarwinella austerocallosa n. sp. is the progenitor of two Eocene species, A. ellioti Zinsmeister, 1976, recorded from Units II-III of the La Meseta Formation, and younger A. nordenskjoldi (Wilckens, 1911), distributed in Units II—V. Antarc- todarwinella became extinct during the late Eocene. These taxa form a lineage with an observed gap in the late Paleocene to early Eocene record in Antarctica. This gap in the record may contribute to the observ- able difference in overall morphology in A. austero- callosa n. sp. and younger Eocene forms A. e/lioti and A. nordenskjoldi, discussed in detail in the systematics section of this work (pp. 31-32). Antarctiranella n. gen. is distinct from other coeval and younger ranellid gastropods, so probably represents a short-lived group that evolved during an early stage of the radiation of this family and became extinct sometime during the Paleocene. Seymourosphaera is closely related to the pseudolivine gastropod, Austrosphaera from the Late Cretaceous to Paleocene of southern Argentina (Tierra del Fuego), and most likely is descended from Aus- trosphaera (Oleinik and Zinsmeister, 1996). Probuc- cinum has been recorded only in Antarctica where it spans the entire Cenozoic beginning in the earliest Pa- leocene and today has a circum-Antarctic distribution in depths of 140 m to more than 600 m (see Dell, 1990). However, there is a gap of nearly 65 m.y. in the fossil record of this group and it 1s surprising that there is no evidence of Probuccinum in the La Meseta Formation or younger Tertiary marine sediments. This may reflect the migration of mid-Tertiary forms to deeper waters, of which we have no record. Paleoaustral gastropods dominate the fauna at 44% (including endemic taxa in accordance with Fleming’s (1963) original ideas). Cosmopolitan groups make up 22% of the total fauna. At species level, however, all taxa are endemic. Thus, the composition of the fauna has generally a cosmopolitan or at least a widespread flavor at genus level with relatively few provincial forms. Further, few taxa recorded in the Antarctic Pa- leocene are present in the Cretaceous deposits in the James Ross Basin, apart from Acmaea, Struthiochen- opus, Euspira, and Taioma, but some are known from other northern and southern regions in Cretaceous de- posits (e.g., Perotrochus, Conotomaria, Bittium, Tur- ritella s.1., Mesalia, Amauropsis, “*Pyropsis,” Levifu- sus?, Serrifusus?, Paleopsephaea, and Cylichnania). Thus, most of the Paleocene Antarctic gastropod fauna is composed of groups that originated in the Late Cre- taceous or earliest Tertiary, either from southern cir- cum-Pacific regions, or the north, or evolved in the Antarctic region and dispersed further afield during the Cenozoic. The patterns of composition of the fauna and biotic recovery in the Paleocene reflect several factors, among them the final breakup of the super- continent Gondwana with ensuing changes to oceanic circulation and climate, and all of these factors play significant roles in the observed biodiversity patterns. The marked endemism at species level for the Ant- arctic Peninsula region during the Paleocene points to a strong degree of provincialism and also isolation from other coeval recorded faunas around the southern circum-Pacific. However, on a higher grade of paleo- biogeographic scale, there is a moderate degree of sim- ilarity of faunas around the southern circum-Pacific margin. This reinforces the proposition posed by Crame (1996) and Stilwell (1997) that the occurrence of dis- junct species of congeners around the southern circum- Pacific reflects evolution in isolation, resulting from retracted distributions of cosmopolitan taxa during the latter part of the Cretaceous. Further, the breakup of Gondwana would have increased the sea-surface tem- perature gradient and maximized shelf area for dis- persal of marine invertebrate taxa, but it would have also enhanced provinciality of faunas due to segmen- tation of presumed oceanic circulation patterns during the latest Cretaceous and early Tertiary (Stilwell, 1997). Progressive continental reshuffling and associ- ated changes in oceanic circulation played a large role in disrupting biotic distributions late in the Mesozoic and early Cenozoic. This trend commenced during the latter part of the Mesozoic, especially during the mid- to Late Cretaceous period, when the final breakup of Gondwana was well underway. During this time the Antarctic fauna belonged to the Austral Province of Kauffman (1973). Preliminary biodiversity and paleobiogeographic trends are relatively consistent with data on the tec- tonic and paleo-oceanographic history of the Austral region, but still require much refinement and rigorous testing. The Early Cretaceous period saw the breakup of East Gondwana, including Australasia, especially by 130 Ma when initial rifting had begun between Australia and greater India (see review of Gondwana breakup by Lawver et al., 1992). Provinciality of shelf 14 BULLETIN 367 faunas increased throughout the Late Jurassic and Ear- ly Cretaceous when most of the Southern Hemisphere belonged to the Austral Province. Although this pro- vinciality decreased from Aptian to Maastrichtian times in the Australian region (Kauffman, 1973; Veev- ers, 1984; Stilwell and Crampton in Henderson et al., 2000; Stilwell and Henderson, 2002), so did the genus- level diversity, reflecting gradual contraction and with- drawal of shallow epicontinental seas with fluctuations throughout the Late Cretaceous (Frakes et al., 1987). Seaways were most widespread during the Aptian-Al- bian in Australia, but were most extensive during the latest Cretaceous for Antarctica, New Zealand, Chat- ham Islands, and New Caledonia, reflecting the final fragmentation of these regions from the Gondwana margin and resultant thermal subsidence and _ trans- gression. As such, there was increased shelf area re- sulting from the transgression, but oceanic circulation patterns were becoming increasingly segmented. Zinsmeister (1982) and Huber and Watkins (1992) proposed that the southern Pacific margin was domi- nated by counterclockwise circulation with a western boundary current flowing southward along Australia and New Zealand comparable to the present-day Ku- roshio Current of the North Pacific. Hence, the south- ern circum-Pacific was, for the most part, isolated by the prevailing oceanic circulation from other major oceans in the Southern Hemisphere. However, during the late Campanian and early Maastrichtian (c. 79 Ma), microfossil evidence, including the presence of latest Cretaceous microfossils in reworked glacial diamicti- tes in the Transantarctic Mountains (Huber and Wat- kins, 1992), points to circum-Antarctic flow of shallow surface waters and the presence of a Trans-Antarctic seaway. Stilwell (1997) presented two scenarios for dispersal of molluscan larvae along shallow, southern circum- Pacific shelves during the latest Cretaceous. First, it is possible that larvae were dispersed from currents flow- ing from the New Zealand—Chatham Rise region to the margins of Marie Byrd Land—Antarctic Peninsula and through the shallow gateway between the Antarctic Peninsula and southern South America. Second, cur- rents originated from the New Zealand—Chatham Rise region and eventually progressed northward through the Trans-Antarctic seaway to reach the Antarctic Pen- insula. Because part of Western Antarctica was thought to be a series of islands (Zinsmeister, 1987), larvae may have been distributed through these areas, not- withstanding the probability of a Trans-Antarctic sea- way. But did this occur? The distances between the New Zealand—Chatham Rise and Antarctic Peninsula/ southern South America regions were still immense during the Late Cretaceous, despite their high-latitude position (approximately 90° of longitude or an esti- mated 4000 km), such that of macroinvertebrates, only those with planktotrophic teleplanic larvae capabilities would have been the most successful of marine organ- isms to make the long journey along the increasingly dissected Gondwana margin. No species-level gastro- pods have a wide distribution in the Southern Hemi- sphere during the latest Cretaceous and only four re- corded gastropods traversed the nearly 1000-km dis- tance along the Chatham Rise—New Zealand subcon- tinent (Stilwell, 1997, 1998). With the final breakup of Gondwana at the close of the Mesozoic, the Austral Province lost its identity. One of the smaller faunal provinces, the Weddellian Province (Zinsmeister, 1979), resulting from the dis- solution of the Austral Province, occupied the region south of the northeastern coast of Australia and New Zealand, extending westward and including the con- tinental shelf areas along Antarctica and southern South America. The concept of the Province can be expanded to include New Caledonia and Chatham Is- lands, based on quantitative analyses of molluscan similarities (Stilwell, 1991, 1994, 1997). Another re- cent study on Maastrichtian gastropods of Antarctica supports the existence of the Weddellian Province dur- ing the latest Cretaceous (Fricker, 1999). Faunal comparisons around the southern circum-Pa- cific indicate that Western Australia can be excluded from the Weddellian Province. Evidence supports the idea that there was virtually no faunal interchange be- tween Western Australia and the southern circum-Pa- cific during the latest Cretaceous (Darragh and Ken- drick, 1991), and also Paleocene faunas of southeast- ern Australia and other Austral localities (Darragh, 1994, 1997). Molluscan evidence (Stilwell, 1994, and JDS, unpublished data) supports the contention that the Weddellian Province was probably short-lived, exist- ing only through the Campanian-Maastrichtian time, after which the province was either reduced quite con- siderably or had broken up into smaller biogeographic entities by the earliest Tertiary, much earlier than the Eocene proposed by Zinsmeister (1979, 1982). Distri- butions of Paleogene Austral mollusks indicate that the Weddellian Province was reduced during the earliest Tertiary to the area of southeastern Australia, New Zealand, and possibly the Chatham Islands, and that the Antarctic Peninsula and southern South America probably also belonged to separate provinces or sub- provinces (Stilwell, 1991, 1994). This pattern most likely reflects the environmental perturbations at the end of the Cretaceous resulting from the continental redistribution (Stilwell, 1997). The Paleocene bivalve fauna of Antarctica is the oldest recorded Austral Cenozoic assemblage and as EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 15 such, provides an important data set for early Paleo- cene faunal composition and paleobiogeographic dis- tributions. As stated by Stilwell (2000), the Paleocene molluscan faunas of Antarctica yield significant infor- mation on the composition of immediate post-K-T fau- nas in the Southern Hemisphere, not found elsewhere, and also patterns of the early recovery phases follow- ing the mass extinction event. The composition of the bivalve fauna corroborates the findings of Stilwell (2000) on the paleobiogeographic history of Paleocene Antarctic gastropods, the details of which will not be repeated herein. In summary, at species level all Antarctic Paleocene bivalves are endemic, indicating that this marked en- demism points to a strong degree of provinciality and also isolation of the Antarctic Peninsula faunas with other Paleocene faunas around the southern circum- Pacific. The Paleocene Antarctic faunas, in all likeli- hood, belonged to a distinct biotic province by Paleo- cene time. The distribution of Paleogene Austral mol- lusks suggests that the Weddellian Province of Zins- meister (1979) was greatly reduced by the early Tertiary and had dissipated into separate biotic entities by this time (see Stilwell, 1997). At genus level the composition of the bivalve fauna has a strong cosmopolitan flavor with a weaker Pa- leoaustral component. Widespread and long-ranging bivalves dominate the assemblage at approximately 75% of the recorded genera of bivalves, including Nu- cula, Leionucula, Nuculana, Ledina?, Jupiteria?, Cu- cullaea, Pinna, Acesta, Saxolucina, Thyasira, and Per- iploma?. Most of these genera provide new and addi- tional records of these groups in the fossil record of Antarctica by extending stratigraphic ranges. As an ex- ample, Saxolucina and Periploma? were previously recognized in the Eocene of Seymour Island (Stilwell and Zinsmeister, 1992), but the Paleocene records ex- pand the range to include first occurrences in the Dan- ian. The possible record of Ledina may indicate an Austral origin for this nuculanid group, previously re- ported from the late early Paleocene of New Zealand (see review by Stilwell, 1994), and subsequent youn- ger Paleogene deposits elsewhere. Only 25% of the bivalves are Paleoaustral forms with a long history in the Southern Hemisphere; these include Australoneilo, Lahillia, Marwickia and Cy- clorisma. Of note, three groups, apart from Marwickia, have latest Cretaceous representatives in the Austral realm, indicating that they crossed the K-T boundary into the Tertiary. Australoneilo and Cyclorisma dis- appeared from the fossil record sometime during the Eocene in Antarctica, whereas Lahillia became extinct during the Miocene in South America. The earliest Pa- leocene Antarctic record of Marwickia predates the New Zealand record (Beu and Maxwell, 1990; Stl- well, 1994) by a few million years. Thus, many of the bivalve and gastropod groups present in the Antarctic Paleocene originated in the Late Cretaceous, either from southern circum-Pacific regions, or the north. Some taxa such as Pinna have had a very long history in Antarctica, being first recorded in Upper Jurassic sediments (Willey, 1975), but disappeared from the fossil record in the Eocene. The disappearance of Aus- traloneilo, Lahillia, Cyclorisma, and other mollusk groups in the Eocene of Antarctica most likely corre- sponds to deteriorating climatic condition at the close of the Eocene. One aspect of the Paleogene faunas of Antarctica that is not commonly recognized is that the shelf re- gion along Antarctica was the source for a number of groups of benthic invertebrates that have a wide and varied distribution in mid- and low latitudes during the latter part of the Cenozoic. Zinsmeister and Feldmann (1984) discussed the phenomenon of heterochroneity of the marine faunas of the Southern Hemisphere. The recognition of the earliest occurrence of a number of mollusks, arthropods and echinoderms on Seymour Is- land clearly indicates that the high southern latitudes around Antarctica during the Paleogene were the site of diversification of the marine faunas associated with climatic change and the development of marked sea- sonality. These newly evolved groups were restricted to the shelf region around Antarctica until conditions in the mid-latitudes cooled enough to allow them to migrate northward. In addition to the northward mi- gration of shallow-water taxa, a number of taxa (Me- tacrinus (crinoid), Zoroaster and Ctenophoraster (sea stars), and Lyreidus (decopod)) migrated into deep ma- rine environments as cooling of the deep-sea environ- ment developed during the Eocene. SUMMARY The early Danian molluscan fauna from the Lopez de Bertodano and Sobral formations provides a unique insight into the origin of the Cenozoic marine fauna following the terminal Cretaceous extinction event. It is clear that climatic cooling during the Maastrichtian and the final breakup of Gondwana had initiated major changes in the composition of marine faunas in the southern high latitudes and set the stage of the mass extinction at the end of the Cretaceous. Although di- versity dropped dramatically at the K-T boundary, ~39% of the molluscan fauna survived the boundary event. Initial recovery of the shelf faunas was char- acterized by floods of opportunitistic groups such as Lahillia and Struthiochenopus followed by the reap- pearance of cosmopolitan and refugia Lazarus species. As the diversification within the faunas began to in- 16 BULLETIN 367 crease, the isolation of Antarctica became more pro- nounced as the other southern continents moved north- ward. Major changes in oceanic circulation associated with the final breakup of Gondwana enhanced the iso- lation of the marine faunas along Antarctica. Only with the onset of glacial conditions and marked cooling of both the shallow and deep-sea realms, did the Antarc- tic faunas begin to migrate northward into the mid- latitudes. SYSTEMATIC PALEONTOLOGY There are of number of nomenclatural problems with several of the taxa described and figured by Otto Wilckens (1910). To understand the source of these problems a brief review of field activities of the Swed- ish South Polar Expedition is necessary. Fossil mate- rial from Seymour Island was collected by Otto Nor- denskjold, Gunnar Andersson and other members of the Swedish South Polar Expedition. Only Gunnar An- dersson was a trained geologist and his work on the island was limited to the last days of the expedition’s stay in Antarctica. Nordenskjold’s field work on Sey- mour Island was hindered by circumstances which pre- vented them from recognizing the remarkable pale- ontologic record on the island. During the two and a half years spent in the James Ross Basin only a limited amount of time was spent collecting fossils. Seven sledging trips to Seymour Is- land were made during this period; except for the last trip led by Gunnar Andersson during late October and early November of 1903, each visit was three days or less in length and none of the personnel on these visits was a trained geologist. Another factor that played a central role in the limited success of their work on Seymour Island was that all sledging trips along the coast were restricted to the east coast which is the least fossiliferous region of the island. The only exception was the Bodman party during November 21 through 25 of 1902, which went along the west coast of the island and crossed through Cross Valley to the east coast to collect penguin eggs at the penguin rookery. Although the Bodman party passed through some of the most fossil-rich regions of the Upper Cretaceous and Danian strata on the island, none of the personnel in Bodman’s party had any scientific training and only a few fossils without any locality data were collected. As a consequence, many of the fossils Wilckens de- scribed had only the most superficial locality data. Only during the last visit to Seymour Island in the spring of 1903 by Andersson were any fossils collect- ed with adequate field data. Combined with the fact that nothing was known about stratigraphy of the Late Cretaceous/earliest Tertiary, several of Wilckens’ taxa were based on material collected from different strati- graphic horizons and ages. Another factor that influ- ences Wilckens’ systematic study of the fauna was the common belief during the early part of the 20th cen- tury that the Danian was the uppermost part of the Cretaceous. It is interesting to note that Andersson (1904) felt that because of the absence of any am- monites, the fossils from the Swedish South Polar Ex- pedition (SSPE) locality 9 were, indeed, Tertiary, but Wilckens included them with the Cretaceous taxa he described. The mollusks described and figured in this paper are housed at the National Museum of Natural History, Washington, DC (USNM); Department of Earth and Atmospheric Sciences, Purdue University (PU); Uni- versity of Buenos Aires, Argentina (UBA); Institute of Geological Sciences, London (IGS); and the Natur- hisktoriska Riksmuseet, Stockholm, Sweden (Mo). Additional material from Seymour Island is housed in the British Museum of Natural History; British Ant- arctic Survey, Cambridge; and the Centro de Investi- gaciones en Recursos Geologicos, Buenos Aires, Ar- gentina. The systematic paleontology section in this work incorporates a complete catalogue of all mollus- can species recorded from the Paleocene of Antarctica. Where appropriate, in some species, the taxonomy is updated and modernized, in accordance with recent ad- vances in molluscan systematics. The Appendix (p. 51) contains stratigraphic data for Maastrichtian and Danian localities on Seymour Is- land, as well as individual occurrences and abundance data for Danian species. Phylum MOLLUSCA Linnaeus, 1758 Class BIVALVIA Linnaeus, 1758 Subclass PALAEOTAXODONTA Korobkoy, 1954 Order NUCULOIDA Dall, 1889 Superfamily NUCULOIDEA Gray, 1824 Family NUCULIDAE Gray, 1824 Subfamily NUCULINAE Gray, 1824 Genus NUCULA Lamarck, 1799 Arca nucleus Lin- Type species (by monotypy). naeus, 1758. Subgenus Leionucula Quenstedt, 1930 Type species (by original designation).—Nucula al- bensis d Orbigny, 1844 Nucula (Leionucula) suboblonga (Wilckens, 1907) Plate 1, Figures 1—4, 8 Nucula suboblonga Wilckens, 1907, pp. 53; 1910, pp. 22—24, pl. 2, figs. la,b, 2; Zinsmeister and Macellari, 1988 p. 256, figs. 3.1—5. EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. iV7/ Nuculoma (Palaeonucula) poyaensis Freneix, 1958 (1956), pp. 157— 158, pl. figs. la, b. Leionucula poyaensis (Freneix). Freneix, 1980, pp. 75—77, pl. 1, figs. 1-4. Dimensions.—Hypotype USNM 404809, length 44 mm; height 30 mm. Type.—Lectotype MO 1424a. Localities.—9, 459, 477, 497, 514, 725, 754, 757, V2 VIGs Vs WHS UNOS WS eA SUS syns iey 1148, 1430, 1431, 1432, 1467, 1473, 1502, 1505, IS06; dSOs TS519l 16975 1529; 1531, 1533, 1534, 1535, 1536, 1537, 1548, 1586. Material.—150 specimens. Stratigraphic distribution.—1040 to 1216 m. Discussion.—This species was originally described from the Upper Cretaceous sequence at Cerro Cazado in southern Patagonia (Wilckens, 1907). In the same paper, Wilckens described a second species of Nucula (L.) ob- longa and separated the two by the more centrally lo- cated umbones of N. (L.) suboblonga. Untortunately he did not figure N. (L.) suboblonga because he did not have a “perfect” specimen. Wilckens (1910) subsequent- ly reported the occurrence of this species on Seymour Island and included the first figure of the species. Freneix (1958) described a similar species (NV. (L.) poyaensis) from New Caledonia. Because the dimensions of N. (L.) poyaensis and N. (L.) suboblonga are nearly identical, we believe that the two are conspecific. Nucula (L.) suboblonga has an extensive range on Seymour Island, first appearing in the middle part of the Maastrichtian of the Lopez de Bertodano and ex- tending through the Sobral Formation. Although it is not very abundant in the Maastrichtian, it becomes a very common element throughout the Danian on Sey- mour Island. Nucula (Leionucula) hunickeni Zinsmeister and Macellari, 1988 Plate 1, figures 6, 7 Nucula (Leionucula) hunickeni Zinsmeister and Macellari, 1988, 256-257, figs. 3.10, 3.11. Dimensions.—Holotype USNM 404814; length 23 mm, height 17 mm, width of paired valves 12 mm. Type.—Holotype USNM 404814. Stratigraphic occurrence.—Middle part of unit | of the Sobral Formation. Localities.—9 (type), 497, 746, 1104, 1505, 1519, 1534. Material.—31\ specimens. Stratigraphic range.—1072 to 1375 m. Discussion.—This species of Leionucula may be distinguished from Nucula (L.) suboblonga by its smaller size and straighter anterior, which slopes at a steeper angle. Nucula (L.) hunickeni has only been en- countered in a dark-brown silty sandstone facies of the Sobral Formation. Nucula species Plate 1, figures 13, 16 Locality.—1535. Material examined.—One poorly preserved speci- men. Stratigraphic range.—1078 m. Discussion.—The atfinity of this poorly preserved, minute nuculid bivalve is uncertain, as the delicate, disarticulated shell is partly immersed in fine matrix. The specimen is 2.5 mm in length and 2.0 mm high, circular to slightly ovate, gently inflated, with orna- mentation of closely spaced commarginal riblets that become coarser and broader near the ventral margin. There is also evidence of a poorly developed radial element. The specimen is reminiscent of Linucula? mcemurdoensis Stilwell, 2000 (p. 265, pl. 1, figs. D. J) from the Eocene of East Antarctica in size and outline, but Nucula sp. has more developed commarginal or- namentation. The sculpture of Nucula sp. 1s compa- rable to Nucula (Leionucula) palmeri (Zinsmeister, 1984) (pp. 1501-1502, fig. 3A, B; Stilwell and Zins- meister, 1992, pp. 47—48, pl. 1, figs. a, b), from Unit II of the La Meseta Formation, also Eocene, of Sey- mour Island, but Nucula sp. is more ovate, whereas N. (L.) palmeri has a subtrigonal outline and more evenly spaced commarginal riblets of mostly equal strength. More material is needed to assess the relationships of this species in detail. Nucula sp. is distinct from N. (L.) suboblonga (Wilckens, 1907) and N. (L.) hunick- eni Zinsmeister and Macellari, 1988, both recorded from the Danian of Seymour Island. Superfamily NUCULANOIDEA H. and A. Adams, 1858 Family NUCULANIDAE H. and A. Adams, 1858 Subfamily NUCULANINAE H. and A. Adams, 1858 Genus NUCULANA Link, 1807 Type species (by original designation).—Arca ros- trata Chemnitz, 1774 (= Arca pernula Miiller, 1771). Nuculana antarctirostrata, new species Plate me ficures ie 12515 Diagnosis.—Small- to medium-sized Nuculana with a narrowly elongate, moderately rostrate, moderately inflated shell; posterior end moderately pointed; um- bones strongly opisthogyrous, small; escutcheon bor- dered by moderately developed, weakly concave um- bonal ridge; ornamentation of closely spaced commar- ginal riblets, overprinted by discordant riblets that be- 18 BULLETIN 367 come more concordant anteriorly and_ posteriorly; posterior part of hinge 70% of length of shell. Description.—Shell small- to medium-sized for ge- nus (length 10.3 mm), thin, narrowly elongate, mod- erately rostrate; shell moderately inflated, more so cen- trally on disk becoming less so at anterior and poste- rior margins; umbones small, strongly opisthogyrous, located more anteriorly; lunule poorly developed; es- cutcheon long, narrow, with weak threads, bordered by gently convex to nearly straight umbonal ridge; anter- odorsal margin short, steeply sloping, scarcely convex, more straight, merging with well-rounded anterior margin; posterodorsal margin long, gently concave, merging with narrowly rounded to subangular, pointed posterior margin; ventral margin moderately broadly convex; more rounded near anterior margin; sculpture of closely spaced commarginal riblets (>10 per | mm) with some marked growth pauses, and moderately pro- nounced discordant riblets, more distinctive on central part of disc and ventrally; discordant riblets become more concordant near anterior and posterior margins; posterior hinge 70% of length of shell; many chevron- shaped hinge teeth becoming weaker near posterior and anterior margins; pallial line poorly developed; in- ner margins smooth. Dimensions.—Holotype USNM 517001, length 10.3 mm, height 6.5 mm, width of paired valves 6.0 mm; paratype USNM 517002, length 7.5 mm, height 5.0 mm (internal). Types.—Holotype USNM 517001; paratype USNM 517002. Locality.—1589. Material examined.—Two specimens. Stratigraphic range.—1149 m. Discussion.—Nuculana antarctirostrata n. sp., one of three nuculanid species newly recorded from the Antarctic Paleocene, belongs to a characteristic latest Cretaceous—early Paleogene group ornamented with discordant commarginal riblets. Nuculana n. sp. of Stilwell (1994, pp. 268-270, pl. 3, figs. 1-2, 5) from the Maastrichtian of Northland, New Zealand, is mor- phologically very similar to N. antarctirostrata, dif- fering in the Antarctic species being slightly smaller with a more narrowly rounded and convex ventral margin and more unevenly spaced, commarginal rib- lets that are more discordant along the central part of the disc. No other Paleocene nuculanid has a compa- rable sculptural configuration. Etymology.—Species named for its endemic Antarc- tic occurrence and its moderately developed rostrum. Genus LEDINA Dall, 1898 Type species (by original designation).—Leda ebo- rea Conrad, 1860 (non Conrad, 1846) (= Leda (Led- ina) smirna Dall, 1898). Ledina? species Plate 1, figures 5, 9, 10 Description.—Shell relatively small (length 7.5 mm nearly complete), thin, polished, subtrigonally elon- gate-ovate, moderately inflated, scarcely rostrate; um- bones subcentral, just more anterior, suborthogyrous, just slightly curved toward posterior; lunule and es- cutcheon poorly differentiated; anterodorsal margin short, steep, gently convex; anterior margin incomplete on available specimen; posterodorsal margin moder- ately long and steep, very gently convex to nearly straight, merging with blunt, narrowly rounded, pos- terior margin; ventral margin broadly rounded; sculp- ture of many, closely spaced commarginal threads and riblets, becoming more spaced and raised ventrally; hinge details unknown; inner margin smooth. Dimensions.—USNM 517003, length 7.5 mm, height 5.5 mm, width of paired valves 4.5 mm. Locality.—1519. Material.—One specimen. Stratigraphic range.—1072 m. Discussion.—This new species is probably assign- able to the Paleocene to Eocene genus Ledina Dall, 1898, but as there are no internal details available and part of the anterior end of the shell is missing, only a tentative assignment is made here. The subovate out- line and slightly rostrate shell, sculpture of slightly variable commarginal riblets, and poorly defined lu- nule and escutcheon in the Antarctic species are all characteristics of Ledina, type species L. smirna (Dall, 1898) (see Puri in Moore, 1969, p. N237, fig. A7-3; Toulmin, 1977, pp. 149-150, pl. 2, figs. 8-9) from the Paleocene of North America. Ledina smirna is larger with finer ornamentation, a slightly broader ventral margin, and a scarcely more developed rostrum, com- pared with Ledina? sp. The rostrum in Ledina? sp. 1s more pronounced, compared with L. taioma (Finlay and Marwick, 1937) (pp. 16-17, pl. 1, figs. 1, 3, 6; Fleming, 1966, p. 106, pl. 4, fig. 59-61; Stilwell, 1994, pp. 727-730, pl. 47, figs. 16, 19-20) from the late early Paleocene of New Zealand, which is also twice the size of the Antarctic species with more pro- nounced growth pauses and a more inflated shell. Led- ina paucigradata (Singleton, 1943) (p. 268, pl. 12, fig. la-b; Darragh, 1994, pp. 77, 79, fig. 1H—I, O—P, R-S, U-V) from the mid-Paleocene of southeastern Victo- ria, Australia, is not a closely related form, as it has a much larger, more elongated shell and more indistinct commarginal ornamentation, compared with Ledina? n. sp. Genus JUPITERIA Bellardi, 1875 Type species (by subsequent designation, Dall, 1898).—Nucula concava Bronn, 1831. EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 19 Jupiteria? species Plate 1, figures 14, 17 Description.—Shell average-sized for family (8 mm in length), thin, moderately inflated, subtrigonally elongate—broadly ovate; length to height ratio 1.15:1; very weakly rostrate; umbones slightly inflated, sub- central, weakly opisthogyrous; umbonal ridge poorly developed; anterodorsal margin moderately sloping, very weakly convex, merging with rounded anterior margin; posterodorsal margin moderately long and de- scending, nearly straight; ventral margin broadly con- vex; shell polished, weakly ornamented with many, closely spaced commarginal striae; inner details un- known. Dimensions.—USNM 517004, length 8.0 mm, height 7.0 mm, width of single left valve, ~2.3 mm. Type.—Hypotype USNM 517004. Localities.—1519, 1538. Material examined.—One specimen. Stratigraphic range.—1072 m. Discussion.—This probable new nuculanid species is of uncertain affinity. Only one nearly complete ex- ternal valve is available. Without hinge details, it is often difficult to distinguish nuculanid genera, but the scarcely rostrate, broad, subtrigonally ovate, smooth and polished shell of closely spaced commarginal stri- ae in this species is reminiscent of Tertiary species of Jupiteria Bellardi, 1875, type species J. concava Bronn, 1831, from the Pliocene of Italy. We can find no closely related species in the Paleogene record in the Southern Hemisphere. Some species of Jupiteria, such as Jupiteria sp. of Maxwell (1992, p. 57, pl. 2, fig. k) from the late Eocene of New Zealand, have similar sculpture or near lack thereof, but Jupiteria? sp. has a more elongate shell and more developed ros- trum, compared with the Antarctic species. Further, few North American species are similar apart from a superficial resemblance to Tindaria sp. 2 of Peterson and Vedelsby (2000, pp. 34—35, fig. 19A—B) from the Paleocene of Nuussuaq, Greenland, but Jupiteria? n. sp. from Seymour Island has less well-defined com- marginal sculpture, less inflated umbones and a less steeply sloping posterodorsal margin, compared with the Greenland species. Family MALLETHDAE H. and A. Adams, 1858 Genus AUSTRALONEILO Zinsmeister, 1984 Type species (by original designation).—Australo- neilo rossi Zinsmeister, 1984. Discussion.—Australoneilo is much more wide- spread than previously recognized, being recorded from the latest Cretaceous? to Paleocene of southern Argentina and Paleocene to Eocene of Antarctica (Zinsmeister and Macellari, 1988), latest Cretaceous of New Zealand (Stilwell, 1994), and mid-Paleocene of southeastern Australia (Darragh, 1994). Reduction in valve inflation and lengthening of shell seem to be the most prominent changes in Australoneilo species from late Campanian? or Maastrichtian to Eocene time, after which the group disappears from the fossil record. Australoneilo gracilis (Wilckens, 1905) and A. casei Zinsmeister and Macellari, 1988, also from the Paleo- cene of Antarctica, appear to be morphologically in- termediate forms between an undescribed species from New Zealand and A. rossi Zinsmeister, 1984, which both share a moderate degree of valve inflation and shell elongation. Australoneilo gracilis, A. casei, and A. cultrata Darragh, 1994, are of close lineal descent and Australoneilo n. sp. may be ancestral as indicated by their close morphological affinity. Australoneilo gracilis (Wilckens, 1905) Plate 1, figures 19, 20, 23 Malletia gracilis Wilckens, 1905, p. 35, pl. 5, fig. 10; Wilckens, 1910, p. 25, pl. 2, fig. 4. Australoneilo gracilis (Wilckens). Zinsmeister and Macellari, 1988, p. 258, fig. 3.6, 3.7; Stilwell, 1994, p. 302. Neilo (Australoneilo) gracilis (Wilckens). Darragh, 1994, p. 79. Dimensions.—USNM_ 517005, length 34.0 mm, height 17.0 mm (right valve and part of hinge). Localities.—9, 497, 1104 1137, 1138, 1414, 1434. Material.—27 specimens. Stratigraphic distribution.—1107 to 1375 m. Discussion.—Zinsmeister and Macellari (1988, p. 258) re-evaluated Australoneilo gracilis (Wilckens, 1905), which is recognized both in uppermost Creta- ceous?—Paleocene deposits of southern Patagonia and in the Danian of Seymour Island. New well-preserved material from Seymour Island and the discovery of a similar species in New Zealand improves our knowl- edge of the relationships of this species. Austaloneilo gracilis is most closely related to Austaloneilo n. sp. of Stilwell (1994, pp. 300-303, pl. 4, figs. 14, 15, pl. 5, figs. 1-6) from the Maastrichtian of Northland, New Zealand. Australoneilo gracilis is slightly more elon- gate and more compressed with a slightly concave pos- terodorsal margin and slightly more pointed posterior margin, compared with the new New Zealand species. See Plate 1, figure 23 for the complete external form of A. gracilis and partial hinge details, previously not figured for this species. Australoneilo casei Zinsmeister and Macellari, 1988 Plate 1, figures 18, 21, 22, 24 Australoneilo casei Zinsmeister and Macellari, 1988, p. 258, figs. 3.8, 3.9; Stilwell, 1994, pp. 302-303. Neilo (Australoneilo) casei (Zinsmeister and Macellari). Darragh, 1994, p. 79. 20 BULLETIN 367 Dimensions.—USNM_ 517006, length 36.0 mm, height 18.0 mm, width of paired valves 15.5 mm (par- tial hinge exposed); USNM 517007, length 28.5 mm, height 17.0 mm, width of paired valves 13.0 mm. Types.—Hypotype USNM 517006; hypotype USNM 517007. Material examined.—Eight specimens. Locality.—746. Stratigraphic range.—1168 m. Discussion.—Australoneilo casei Zinsmeister and Macellari, 1988, is most closely allied with A. cultrata Darragh, 1994 (p. 79, fig. 1A—G) from the mid-Paleo- cene of southestern Australia, but is differentiated from the Australian species in having a slightly larger shell and a smooth shell nearly void of ornamentation apart from very fine commarginal striae. The outlines and convex ventral margins of A. casei and A. cultrata are strikingly similar. The dorsal margin and partial hinge of A. casei are depicted herein in Plate 1, figs. 21, 22 to illustrate the hinge teeth, external ligament and articulated left and right valves, not clearly visible in Zinsmeister and Macellari (1988). Subclass PTERIOMORPHIA Beurlen, 1944 Order ARCOIDA Stoliczka 1871 Superfamily ARCOIDEA Larmarck, 1809 Family CUCULLAEIDAE Stewart, 1930 Genus CUCULLAEA Lamarck, 1801 Type species (by subsequent designation, Children, 1823).—Cucullaea auriculifera Lamarck, 1801. Cucullaea ellioti Zinsmeister and Macellari, 1988 Plate 2, figures 1—6 Cucullaea ellioti Zinsmeister and Macellari, 1988, p. 261, figs. 5.1— 10. Cucullaea n. sp. Zinsmeister and Macellari, 1983, p. 68, Fig. 2al. Dimensions.—USNM 404838, length 51 mm, height 35 mm, width of single valve 16 mm. Type.—Holotype USNM 404838. Localities.—9 (type), 477, 485, 496, 497, 631, 746, TAOS BOLUS WMS 55 VI SGN eG mols os alo2. 1430, 1431, 1434, 1435, 1508, 1510, 1529, 1531, 1534, 1536, 1537, 1601. Material.—158 specimens. Stratigraphic distribution.—1051 to 1369 m. Discussion.—Cucullaea ellioti is easily separated from the Maastrichtian C. antarctica by its smaller size, less inflation of valves, greater elongation, and narrow ligamental region. The absence of a myophoric flange also serves to distinguish C. ellioti from C. an- atarctica. Cucullaea ellioti makes its first appearance within the ‘““K-T Glauconite” and forms an important element of the Danian bivalve fauna in Unit 10 and the Sobral Formation. Although it was originally believed to have made its first appearance below the K-T boundary (Zinsmeister and Macellari, 1983), C. ellioti is now considered to make its first appearance in the Danian. All occurrences in the ““K-T Glauconite” are above the Lower Glauconite which marks the K-T boundary. Order MYTILOIDA Feérussac, 1822 Superfamily PINNOIDEA Leach, 1819 Family PINNIDAE Leach, 1819 Genus PINNA Linnaeus, 1758 Type species (by subsequent designation, Children, 1823).—Pinna rudis Linnaeus, 1758. Discussion.—Pinna had a long presence in Antarc- tica, with the oldest records extending into the Late Jurassic (Tithonian) (Willey, 1975), and disappeared in the fossil record during the late Eocene (see Stilwell and Zinsmeister, 1992). Pinna freneixae Zinsmeister and Macellari, 1988 Plate 2, figures 7-10 Pinna freneixae Zinsmeister and Macellari, 1988, p. 265, fig. 3.16; Stilwell, 1994, p. 354; Stilwell, 1998, p. 37. Dimensions.—USNM 517008, length 83.5 mm in- complete; USNM 517009, length 83.0 mm. Type.—Hypotype USNM 517008: hypotype USNM 517009. Localities 497, 746, 769, 772, 776, 763, 764, 1132, 1134, 11136; 1139) 1150; 1179) 118i 169s: Material examined.—18 specimens. Stratigraphic range.—431 to 1369 m. Discussion.—Pinna freneixae Zinsmeister and Ma- cellari, 1988, previously thought to have become ex- tinct at the close of the Maastrichtian, is now known to have crossed the K-T boundary in the earliest Dan- ian. Adding to discussion of this species by Zinsmeis- ter and Macellari (1988, p. 265), P. freneixae has also an apical angle ranging from 23° to 26°, very close to Pinna sp. of Stilwell (1994, pp. 353-354, pl. 9, fig. 1, 3; Stilwell, 1998, pp. 36-37, fig. 3K G), from the Cam- panian? to Maastrichtian of New Zealand and Chat- ham Islands, which has an apical angle of 20°. Pinna sobrali Zinsmeister, 1984 (p. 1510, fig. 5G, H; Stilwell and Zinsmeister, 1992, pp. 59-60, pl. 3, figs. j, k) from the uppermost Unit VII of the La Meseta Formation (upper Eocene) of Seymour Island, is a closely related species and probably the descendant of P. frenetxae. EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 74} | Order PTERIOIDA Newell, 1965 Suborder PTERIINA Newell, 1965 Superfamily LIMOIDEA Rafinesque, 1815 Family LIMIDAE Rafinesque, 1815 Genus ACESTA Adams and Adams, 1858 Type species (by monotypy).—Ostrea excavata Fa- bricius, 1780. Acesta webbi Zinsmeister and Macellari, 1988 Acesta webbi Zinsmeister and Macellari, 1988, pp. 267—268, figs. 91-3. Dimensions—USNM 405769, length 56 mm, height 71 mm, width of paired valves 30 mm. Type.—Holotype USNM 405769. Localities.—1119, 1134, 1135, 1139, 1548. Material.—Seven specimens. Stratigraphic range.—900—-1145 m. Discussion.—Acesta webbi 1s easily separated from A. shackeltoni by its smaller size, more elongated shell outline, and near absence of radial sculpture. The al- most total absence of radial ornamentation is uncom- mon among members of the family Limidae. “*Lima” cf. L. latgens Feruglio 1936 (pl. 14, figs. 10, 11) from the Maastrichtian of Lago Argentino in Patagonia is very similar to A. webbi, but the posterior auricle is not as broad and the shell is not as inflated. Genus SEYMOURTULA Zinsmeister in Zinsmeister and Macellari, 1988 Type species (by original designation).—Lima an- tarctica Wilckens, 1910. Seymourtula antarctica (Wilckens, 1910) Lima (Limatula) antarctica Wilckens, 1910, pp. 16-17, pl. 1, fig. 8: Fleming, 1978, p. 52, fig. 26 (not S. antarctica Wilckens). Seymourtula antartica (Wilckens, 1910). Zinsmeister and Macellari, 1988, figs. 8.12, 8.13. Dimensions.—USNM 405787, length 32 mm, height 18 mm. Types.—Holotype Mo 1636; hypotypes USNM 405787, 405788, 405789, 405790. Localities.—7154, 757, 763, 776, 1109, 1110, 1116, 1143, 1172, 1178, 1190, 1468, 1591, 1620, 1632. Material.—33 specimens. Stratigraphic range.—692 to 1053 m. Discussion.—Although Seymourtula antarctica is not a common bivalve and is not represented by a large number of individuals, it does have has an extensive range through all the Maastrichtian on Seymour Island and finally disappears in the earliest Danian in the Fish bed horizon of the ““K-T Glauconite.””> When encoun- tered, S. antarctica normally is represented by several individuals. The co-occurrence of several individuals probably represents the gregarious habit of some spe- cies of limids of attaching in clusters to some solid surface. Suborder OSTREINA Ferussac, 1822 Superfamily OSTREOIDEA Rafinesque, 1815 Family OSTREIDAE Rafinesque, 1815 Subfamily OSTREINAE Rafinesque, 1815 Genus OSTREA Linnaeus, 1758 Type species (by subsequent designation, ICZN Opinion 94).—Ostrea edulis Linnaeus, 1758. Ostrea species Localities.—1131, 1483. Material.—Two specimens. Stratigraphic occurrence.—1065 to 1125 m. Discussion.—Oysters are very rare in the Danian of either the Lopez de Bertodano or Sobral formations. Likewise they are also very rare in the Maastrichtian of the Lopez de Bertodano and the Eocene La Meseta formations. The near absence in the Maastrichtian and the Danian probably reflects unfavorable facies for the group, but the limited occurrence of oysters in the shallow-water tidal-dominated facies of the La Meseta Formation is puzzling. The rareness of the ostreids on Seymour Island may reflect the high-latitude location of the island during the Late Cretaceous and early Ce- nozoic. Subclass HETERODONTA Neumayr, 1884 Order VENEROIDA H. and A. Adams, 1856 Suborder LUCININA Dall, 1889 Superfamily LUCINOIDEA Fleming, 1828 Family LUCINIDAE Fleming, 1828 Subfamily LUCININAE Fleming, 1828 Genus SAXOLUCINA Stewart, 1930 Type species (by original designation).—Lucina saxorum Lamarck, 1806. Saxolucina antarctipleura, new species Plate 3, figures 7—13 Diagnosis.—Medium-sized lucinid with subcircular shape and near 1:1 length to height ratio; lunule pro- nounced, narrow, subclavate; escutcheon long, narrow; sculpture of closely spaced, mostly even commarginal riblets (about 3 per | mm), and many secondary threads; ligament external, narrow, elongated, pencil- shaped. Description.—Shell medium-sized for family (up to 30 mm in length), moderately thick, subcircular, dis- 2D, BULLETIN 367 coidal, moderately compressed; equivalved; length to height ratio nearly 1:1; lunule well-developed, but nar- row, elongated, subclavate, slightly depressed, mod- erately deep, escutcheon long, narrow, moderately deep; anterodorsal margin short, slightly concave, moderately steep, merging with well-rounded anterior margin; posterodorsal margin moderately long, nearly straight, margin with somewhat bluntly angular pos- terior margin; ventral margin strongly convex; orna- mentation of evenly spaced, moderately developed, primary riblets (~3 per 1 mm) and many weak, inter- stitial striae, primaries gradually strengthening from umbones to ventral margin; left valve with two car- dinal teeth, anterior one triangular and posterior one elongated, details of teeth uncertain as hinges poorly preserved; external ligament strongly developed, elon- gated, narrow, pencil-shaped; inner margin smooth. Dimensions.—Holotype USNM 517010, length 21.0 mm, height 18.5 mm, width of paired valves ~8.0 mm; paratype USNM 517011, length 30.0 mm, height 28.0 mm; paratype USNM 517012, length 22.0 mm, height 22.0 mm, width of paired valves 8.0 mm. Types.—Holotype USNM 517010; paratypes USNM 517011, 517012. Localities.—746, 1105, 1131 (type), 1137, 1161, 1430, 1467, 1535. Material examined.—33 specimens. Stratigraphic range.—1065 to 1369 m. Discussion.—The ancestor-descendant relationship of Saxolucina antarctipleura n. sp. and S. sharmani (Wilckens, 1911) (p. 12, pl. 1, fig. 11; Zinsmeister, 1984, p. 1513, fig. 7M—N; Stilwell and Zinsmeister, 1992, p. 64, pl. 4, figs. j, n; Stilwell, 2000, pp. 278— 279, pl. 3, fig. C-D, EK H), from the middle to late Eocene of Seymour Island and McMurdo Sound, East Antarctica, is secure. There is little to distinguish be- tween S. antarctipleura n. sp. and S. sharmani, except that the Paleocene species is generally larger with a slightly more inflated shell and the commarginal riblets tend to flatten out slightly posteroventrally, compared to the circum-Antarctic Eocene species. Lucina scotti (Wilckens, 1910) (p. 57, pl. 3, fig. 2a, b; Zinsmeister and Macellari, 1988, p. 273, figs. 9.5, 9.6) from the late Maastrichtian of Seymour Island is not a closely related form, as the umbones are nearly central and the ornamentation is of much more pronounced commar- ginal ribs. The Tertiary South American species, Lu- cina promaucana Philippi, 1887 (p. 175, pl. 24, fig. 6; see Ortmann, 1902, pp. 130-131, pl. 27, fig. 4a, b), is also a closely related form and may be congeneric, differing from the Paleocene Antarctic species in hav- ing a longer anterodorsal margin and more projecting umbones. Etymology.—Species named for its endemic pres- ence in Antarctica and from the Greek plewron (equiv- alent to “rib, side’’) for its closely spaced, commar- ginal riblets. Family THYASIRIDAE Dall, 1901 Genus THYASIRA Leach in Lamarck, 1818 Type species (by original designation).—Amphides- ma flexuosa Lamarck, 1818. Thyasira austrosulca, new species Plate 3, figures 14—17 Diagnosis.—Minute, moderately inflated, subcircu- lar thyasirid (maximum height 5.5 mm), umbones strongly prosogyrous; posterior sulcus strongly devel- oped, situated nearly flush with posterior margin; shell polished with poorly developed ornamentation of com- marginal threads that increase in strength slightly from umbones to ventral margin. Description.—Shell small for genus and family (up to 5.5 mm high), thin, moderately inflated, subcircular; length to height ratio nearly 1:1; umbones small, slightly pointed, situated centrally along dorsal mar- gin; strongly prosogyrous, anterodorsal margin steeply sloping, short, very gently concave, merging with strongly convex anterior margin; posterodorsal margin with strong sulcation, positioned nearly flush with pos- terior margin about 10% of distance of length of shell from posterior margin; posterior margin moderately long, only marginally convex, merging with bluntly truncated sulcation; outer margins of posterior sulcus gently concave; ventral margin well-rounded, convex; shell polished, mostly smooth, apart from very weak ornamentation of many, commarginal threads, increas- ing in strength slightly from umbones to ventral mar- gin, where they become a bit more spaced and un- equal; hinge and inner details unknown. Dimensions.—Holotype USNM 517013, length 5.3 mm, height 5.5 mm; paratype USNM 517015, length 5.3 mm, height 4.5 mm. Types.—Holotype USNM 517013, paratype USNM 517015. Locality.—1519 (type). Material examined.—Two specimens. Stratigraphic range.—1073 m. Discussion.—This new small thyasirid bivalve is represented by one articulated specimen and also by a slightly decorticated left valve. Thyasira austrosulca n. sp. has no recorded close relative in the Cenozoic record of Antarctica, and seems to be most closely allied to a Recent circum-Antarctic species, 7. dear- borni Nicol, 1965 (p. 79, pl. 8, figs. 1, 2; Nicol, 1966, p. 62, figs. 7, 8; Dell, 1964, p. 207, fig. 4, nos. 10, 11; Dell, 1990, p. 56, figs. 91, 92), found today in depths between 351 and 836 m. Thyasira austrosulca is a bit EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. smaller and has a slightly broader posterior sulcus compared with 7. dearborni, but there is little else to distinguish these closely related forms. In all likeli- hood, 7. austrosulca is the ancestor of 7. dearborni. Dell (1990) noted intraspecific variation in the mor- phology of the posterior sulcus in 7. dearborni, but we can find no differences in the two specimens of T. austrosulca. Another closely related Austral species is Thyasira sp. of Darragh (1994, p. 89, fig. 4P. Q) from the mid-Paleocene of Australia, which reaches a length and height of 7.2 mm. Thyasira sp. of Darragh (1994) has a more circular, slightly larger shell and a margin- ally weaker sulcus compared with the Paleocene Ant- arctic species, but again there is little to differentiate these taxa, which are seemingly from the same stock. Thyasira austrosulca may be separated from the Maas- trichtian 7. townsendi White from the Lopez de Ber- todano Formation by its small size and the absence of a broad, very deep sulcus that characterizes the pos- terioventral margin of 7. townsend. Etymology.—Species named for its Austral occur- rence and from the Latin sulcus (equivalent to “‘fur- row, groove’’) for its prominent posterior sulcus. Superfamily CARDIOIDEA Lamarck, 1809 Family LAHILLIIDAE Finlay and Marwick, 1937 Genus LAHILLIA Cossmann, 1899 Type species (by subsequent designation, Finlay and Marwick, 1937).—Amathusia angulata Philippi, 1887. Lahillia larseni (Sharman and Newton, 1897) Plate 2, figures 11-14 Cyprina larseni Sharman and Newton, 1897, pp. 59-60. pl. 1. Lahillia lusia Wilckens, 1910, pp. 58-63, pl. 3, figs. 4, 5, 6, 7a—c, 11; Zinsmeister and Macellari, 1983, p. 68, fig. 2, B3. Lahillia larseni (Sharman and Newton). Zinsmeister and Macellari, 1988, pp. 276-277, figs. 15.1-S. Dimensions.—USNM 405803, length 105 mm, height 94 mm, width of paired valves 72 mm. Type.—Holotype IGS 4053. Type locality.—No locality given by Sharman and Newton (1897) other than Seymour Island. Localities.—9, 477, 485, 496, 631, 757, 776, 777, (7S MVIZOl VI3Bie W345 11355 1136; 1137, 1148, Lier, 1192, 1430, 1431, 1432, 1435, 1473, 1499, 1501, 1504 ISOS 1529 ASS 1532. Material.—110 specimens. Stratigraphic range.—867 to 1200 m. Discussion.—Lahillia larseni was originally de- scribed by Sharman and Newton (1897) from a me- dium-sized paired-bivalved specimen collected by Captain A. Larsen during his first visit to Seymour Island during the austral summer of 1892—93. Since Nw ee) the material Sharman and Newton had previously de- scribed from Seymour Island was Tertiary and they were not aware of Cretaceous strata on the island, they assumed that the undescribed species of Lahillia was also of Tertiary age. The existence of Cretaceous age sediments was not recognized until the Swedish South Polar Expedition at the beginning of the 20th century. As a consequence, Sharman and Newton referred L. larseni to the Tertiary, which Wilckens (1911) fol- lowed. Wilckens (1911) referred the Cretaceous spe- cies collected by the Swedish South Polar expedition to the South American species L. /usia. Examination of Larsen’s specimen and the collection of a large number of additional specimens from the Eocene La Meseta Formation has revealed that Larsen’s specimen is distinct from the Eocene species. Comparison of the Sharman and Newton specimen with the Maastrich- tian/Danian Lahillia clearly shows the two to be con- specific. It is also clear that the Seymour Island species is distinct from the L. /usia from Patagonia (Zins- meister and Mascellari, 1988). As a consequence, the specific name L. larseni is now applied to the Maas- trichtian/Danian species of Lahillia in the Lopez de Bertodano and Sobral formations. The eroded nature of the shell together with extensive fieldwork on Sey- mour Island suggest that the specimen of L. larseni that Larsen found most likely was found on the beach north of Penguin Point. Eroded Cretaceous fossils are occasionally encountered along the beach in this area. This is the area where Larsen and his men landed on their first visit to the island. Lahillia larseni makes its first appearance in unit 8 of the Lopez de Bertodano Formation and though pre- sent at most localities, it forms a relatively minor com- ponent of the molluscan fauna. In the lowermost Dan- ian, immediately above the ““K-T Glauconite,” the abundance of L. larseni increases dramatically and is characterized by floods of thousands of individuals. This sudden increase in abundance is believed to re- flect the opportunistic nature of the species. The ab- sence of competition following the mass extinction at the end of the Cretaceous enabled L. larseni to become the dominant element in the shelf faunas in the Sey- mour Island region during the earliest Danian. With the diversification and appearance of new benthic taxa, the floods of lahillia disappeared. Although L. larseni remains an important element of the Danian shelf fau- nas in the Seymour Island region, the floods of thou- sands of individuals are restricted to the interval dur- ing the period immediately following the extinction event. Lahillia huberi Zinsmeister and Macellari, 1988 Plate 3, figures 1, 2 Dimensions. —USNM 405817, length 71 mm, height 64 mm, width of paired valves 44 mm. 24 BULLETIN 367 Types.—Holotype USNM 405817; paratypes USNM 405818, 405819. Localities.—9, 496, 631, 746 (type), 1136, 1148, 1192, 1698. Material.—41 specimens. Stratigraphic range.—1134 to 1179 m. Discussion.—Lahillia huberi may be distinguished from L. larseni by its smaller size, subtrigonal shell outline, orthogyrate beaks, and an only moderately concave anterior margin. The nymph of L. /arseni is considerably more massive, longer, and extends above the margin of the valves. Suborder ARCTICINA Newell, 1965 Superfamily VENEROIDEA Refinesque, 1815 Family VENERIDAE Rafinesque, 1815 Subfamily PITARINAE Stewart, 1930 Genus MARWICKIA Finlay, 1927 Type species (by original designation).—Finlaya parthiana Marwick, 1927. Marwickia woodburnei Zinsmeister and Macellari, 1988 Plate 3, figures 3-6 Astarte ct. A. venatorum Wilckens, 1910, pp. 49-50, pl. 2, figs. 28a, b, not figs. 29 a, b. Dimensions.—USNM 405804, length 30 mm, height 29 mm, width of paired valves 16 mm. Types.—Holotype USNM 405804; paratypes USNM 405805, 405834. Localities.—9 (type), 746, 1130, 1131, 1134, 1135, 1136, 1137, 1138, 1139, 1148, 1149, 1189, 1414, 1432, 1434, 1435, 1448, 1467, 1502, 1504, 1507, 15035, S10; W529 slS3 0 153i 53261533. 1934, 1536; 15875 1538, 15869 15895 1695, 1697; Material.—137 specimens. Stratigraphic range.—1052 to 1216 m. Discussion.—Venerid bivalves are rare in the Lopez de Bertodano and Sobral formations and are charac- terized by a similar inflated ovate shell. Species are separated by variation of the hinge elements. Wilckens (1910) tentatively referred specimens from SSPE lo- cality 8 on Snow Hill Island and SSPE 9 on Seymour Island to the genus Astarte. Zinsmeister and Macellari (1988) believed that the assignment of the specimens from Seymour Island to Astarte was based on the as- tarte-like hinge of the fragmented specimens from Snow Hill Island. The presence of an anterior lateral tooth on specimens from Seymour Island clearly shows that they belong to the venerid subfamily Pi- tarinae and not in the family Astartidae. Marwickia woodburnei is easily separated from the Maastrichtian venerid species Cyclorisma chaneyi Zinsmeister and Macellari, 1988, by the presence of an elongated an- terior lateral and by a more centrally located umbone. Order MYOIDA Stoliczka, 1870 Suborder MYINA Stoliczka, 1870 Superfamily HIATELLOIDEA Gray, 1824 Family HIATELLIDAE Gray, 1824 Genus PANOPEA Menard de la Groye, 1807 Mya glycimeris Born, 1778. Type species. Panopea clausa Wilckens, 1910 Plate 3, figures 20—22 Panopea (Pleuromya?) clausa Wilckens, 1910, 68—69, pl. 3, figs. 10a, b. Panopea clausa Wilckens. Woods, 1917, p. 33, pl. 18, figs. 6a, b, 7; Freneix, 1958, p. 343, pl. 3, fig. 6; Warren and Speden, 1978, p. 40, fig. 26-13; Zinsmeister and Macellari 1988, pp. 280-282, figs. 16.1-3. Localities.—458, 459, 757, 769, 776, 1116, 1146, 1176, 1178, 1180, 1190, 1426, 1471, 1476, 1489, 1492, 1540, 1584, 1595, 1614, 1615, 1620, 1622. Material.—15 specimens. 344 to 1056 m. Discussion.—Although Panopea clausa is not a common bivalve and is not represented by a large number of individuals, it does have an extensive range through all the Maastrichtian on Seymour Island and finally disappears in the earliest Danian in the “K-T Glauconite” fish bed horizon. Surprisingly, P. clausa or related species of Panopea are not present in either Danian of Unit 10 or the Sobral Formation. The genus reappears in the Eocene La Meseta formation at the north end of the island. Stratigraphic range. Subclass ANOMALODESMATA Dall, 1889 Order PHOLADOMYOIDA Newell, 1965 Superfamily PANDOROIDEA Rafinesque, 1815 Family PERIPLOMATIDAE Dall, 1895 Genus PERIPLOMA Schumacher, 1817 Type species (by monotypy).—Corbula margarita- cea Lamarck, 1801. Periploma, new species Plate 3, figures 18, 19 Description.—Shell moderate-sized for family and genus (25.0 mm long), thin, slightly inflated, obliquely subovate, attenuate and compressed anteriorly; nearly equivalved; inequilateral; umbones small, scarcely in- flated, prosogyrous; anterodorsal margin short, mod- erately sloping, straight, merging with obliquely trun- cated anterior margin; posterodorsal margin moderate- EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 25 ly long, gently sloping, broadly convex, merging with well-rounded posterior margin; ventral margin strong- ly convex; ornamentation of low, rounded, closely spaced, commarginal riblets, growing in strength only slightly towards ventral margin; posterior gape only slightly developed; internal details unknown. Dimensions.—USNM_ 517014, length 25.0 mm, height 21.8 mm, width of paired valves 9.5 mm. Locality. —1138, 1484, 1519, 1538. Material examined.—Four specimens. Stratigraphic range.—1051 to 1104 m. Discussion.—This new species represents a member of the Periplomatidae, and is tentatively assigned to Periploma Schumacher, 1817, as it has the character- istic thin, obliquely subovate shell with an attenuate, compressed and slightly truncated anterior end; slight- ly gaping posterior end; small umbones; and closely spaced commarginal riblets, comparable to Cenozoic members of the family and genus. In outline, no other Antarctic fossil or Recent form approaches Periploma? n. sp. Periploma topei Zinsmeister, 1984 (pp. 1525— 1526, fig. 1OR G; Stilwell and Zinsmeister, 1992, p. 89, pl. 10, fig. e, I) and Periploma n. sp.? cf. P. topet Zinsmeister of Stilwell (2000, p. 290, pl. 5, fig. G) from the middle Eocene of Seymour Island and Mc- Murdo Sound have much larger, more compressed and obliquely ovate shells, compared with Periploma? n. sp. Periploma topei is doubtfully the descendant of Periploma? sp. Thracia subgracilis (Whitfield, 1880) (p. 419, pl. 11, figs. 29-30; Stanton, 1920, pp. 26-27, pl. 3, figs. 4a, b, Sa, b, Anatina; Cvancara, 1966, pp. 357-358, pl. 9, figs. 19, 20, Laternula?) from the Pa- leocene of North America has a similar outline and sculpture, more so than any other coeval forms from the Northern or Southern Hemisphere, except that 7. subgracilis has a slightly less circular shell with a cor- responding more convex posterodorsal margin and marginally more attentuate anterior margin, compared with Periploma? n. sp. The genus-level assignment of T. subgracilis is in a state of flux. The compressed nature of both 7. subgracilis and Periploma? n. sp. is identical. Of note, Thracia subgracilis doubtfully be- longs in Thracia, and is most likely a member of Per- iplomatidae. Class GASTROPODA Cuvier, 1797 Subclass STREPTONEURA Spengel, 1881 Order ARCHAEOGASTROPODA Thiele, 1925 Suborder PLEUROTOMARIINA Cox and Knight, 1960 Superfamily PLEUROTOMARIOIDEA Swainson, 1840 Family PLEUROTOMARIIDAE Swainson, 1840 Genus CONOTOMARIA Cox, 1959 Type species (by original designation).—Pleuroto- maria mailleana d Orbigny, 1843. Conotomaria species A Plate 4, figures 1, 2 Description.—Shell large with maximum diameter to 106.7 mm, thin (0.9 mm at base of last whorl), trochiform, broadly conical, as broad as high; spire angle ~69.8°; 7% whorls preserved; region between suture and selenizone convex; region between seleni- zone and periphery straight; suture abutting below pe- ripheral keel; selenizone moderately broad (5.6 mm; 0.15 ramp width), entirely below peripheral keel, flush to slightly convex; sculpture of fine spiral cords stron- gest at shoulder, 10-12 between selenizone and suture, along keel; base very weakly convex with only axial growth lines; periphery with pronounced keel: colu- mellar callus thin, nacreous, spanning 0.25 mm base radius; aperture ovate (height/width = 0.69 mm); um- bilicus deep and narrow. Dimensions.—USNM 511842, height 62.5 mm, di- ameter of last whorl 106.7 mm. Localities.—9, 1105, 1535. Material.—Three specimens. Stratigraphic range.—1077 to 1169 m. Discussion.—This species, assignable to Conoto- maria, differs from Pleurotomaria tardensis Stanton, 1901 (pp. 29-30, pl. 7, figs. 1, 2), from the Upper Cretaceous Belgrano Beds of Argentina (Patagonia), in having a higher spire, thinner and much larger shell, narrower selenizone, lack of spiral sculpture on the base of the shell, presence of a sharp peripheral keel, and in having a narrower and thinner columellar cal- lus. It is also distinguished from Perotrochus? larsen- iana (Wilckens, 1910), from the late Maastrichtian and early Paleocene of Seymour Island, in having a more angular outline, convex whorls, broader umbilicus, and position of selenizone on the mid-whorl, as well as the presence of thin, but prominent spiral threads. Cono- tomaria sp. A is closely allied with the Cretaceous type species, C. mailleana (d’Orbigny, 1842) (pp. 253-254, pl. 195), from France, but has slightly more convex whorls, a less distinct selenizone, and a slightly less developed peripheral keel. Conotomaria species B Plate 4, figures 3, 4 Description.—Shell small (maximum diameter of last whorl 44.8 mm), relatively thick (1.2 mm on ramp 26 BULLETIN 367 of last whorl), trochiform, broadly conical, extrapolat- ed to be broader than high; spire angle ~86.4°; three whorls preserved: region between suture and seleni- zone and periphery straight to concave; suture abutting below peripheral keel; selenizone moderately broad (1.8 mm; 0.16 mm ramp width), spanning mid-whorl; sculpture of numerous, thin, spiral cords (8 between suture and selenizone, 3 on selenizone, 6 between se- lenizone and periphery) and fine, oblique growth lines; periphery with prominent rounded keel; base poorly preserved, weakly convex, with fine spiral cords; shell anomphalous, with remains of strong columellar cal- lus; aperture narrowly ovate, height to width ratio of 0.40:1. Dimensions.—USNM 511843, height 32.5 mm, di- ameter of last whorl 44.8 mm. Locality.—9. Material.—Four specimens. Stratigraphic occurrence.—1168 m. Discussion.—This small species is very distinct among all other Pleurotomartidae on Seymour Island, in having a comparatively small size, distinctly angu- lated appearance, and prominent spiral sculpture. It also has a significantly thicker shell, in proportion to the size. In outline and size, Conotomaria sp. B is comparable with Pleurotomaria gurgitis Brongniart in Cuvier and Brongniart, 1822 (p. 96, pl. 9, fig. 7A, B; d’Orbigny, 1842, pp. 249-250, pl. 192, figs. 4-6) from the Gault region, France, but the whorls in Conoto- maria sp. B are slightly more flush and less convex, and the ornamentation is a bit weaker, compared with P. gurgitis. The specimen figured in Cuvier and Brongniart (1822) (see especially pl. 9, fig. 7A) is higher spired with no details of a selenizone. Conotomaria species C Plate 4, figures 5, 6 Description.—Shell medium- to large-sized (maxi- mum diameter of last whorl 89.2 mm), thick (~1.3 mm on ramp of last whorl), broadly conical, slightly broader than high; spire angle ~81.9°; 8.5 whorls pre- served; region between suture and selenizone convex, between selenizone and periphery straight to slightly convex; suture shallow, canaliculate; selenizone mod- erately broad (2.7 mm, 0.18 mm ramp width), slightly concave spanning mid-whorl; sculpture of thin, raised cords (from 7 on juvenile specimen to 16-18 on adults) between suture and selenizone, from 6—7 on juvenile to 11-12 on adults between selenizone and periphery, and fine, oblique growth lines; periphery marked with prominent angulated shoulder; base weakly convex, with fine spiral cords and axial growth lines; remains of the columellar callus nacreous and thin; umbilicus closed; aperture broad, roundly rect- angular. Dimensions.—USNM 511844, height 69.0 mm, di- ameter of last whorl 86.9 mm. Material.—Eight specimens. Localities.—9, 746, 1104, 1149. Stratigraphic range.—1052 to 1375 m. Discussion.—This species closely resembles Cono- tomaria sp. A. It differs, however, in having a broader, distinctly concave selenizone, canaliculated suture, thicker shell, presence of spiral threads on the base, generally lower and more compressed spire, closed umbilicus, and broader subrectangular aperture. As with Conotomaria sp. A and B, this species is left in open nomenclature until better preserved specimens are collected. Order PATELLOGASTROPODA Lindberg, 1986 Suborder DOCOGLOSSA Troschel, 1866 Superfamily PATELLOIDEA Rafinesque, 1815 Family ACMAEIDAE Carpenter, 1857 Genus ACMAEA Eschscholtz, 1830 Type species (by subsequent designation).—Acmaea mitra Eschscholtz, 1833. Discussion.—Acmaea species are characterized by variably smooth or radially ribbed limpet-like shells with generally an ovate outline and subcentral apex (Abbott, 1974, p. 28; see Lindberg, 1988). The geo- logic range of Acmaea is Cenomanian to Recent (Dockery, 1993, p. 43), although some workers sug- gest that fossil Acmaea-like gastropods belong else- Where (Lindberg, 1988; W. Ponder, personal commu- nication, 2001). The range of the group in Antarctica is restricted to the latest Cretaceous to the earliest Pa- leocene on Seymour Island. Acmaea submesidia, new species Plate 5, figures 1—4 Acmaea n. sp. 2 Zinsmeister et al., 1989, p. 733, fig. 2. Diagnosis.—Somewhat small Acmaea species with a maximum shell diameter of just over 10 mm and a thin, ovate shell of 0.5 mm thick; apex, although sub- central, is more anterior, located about a quarter of the length of shell from anterior margin; differs from type, A. mitra, in having a less elevated shell, a more ovate outline and more anteriorly situated apex. Description.—Shell relatively thin, porcelaneous, ovate with maximum diameter of just over 10 mm; conic in shape with rounded base; apex strongly ele- vated and pointed, but not sharply so, subcentral, sit- uated approximately a quarter of length of shell from anterior margin; surface of shell smooth, as is interior; EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. Zi muscle scars broadly crescent-shaped, connected by thin anterior line which is elevated above the base. Dimensions.—Holotype USNM 511846, length 14.5 mm, maximum diameter 15.5 mm, height 7.5 mm; paratype USNM 511847, length 7.25 mm, maximum diameter 6.0 mm, height ~3.5 mm. Types.—Holotype USNM 511846; paratype USNM 511847. Localities. 477, 1131, 1534, 1548, 1560 (type). Stratigraphic range.—1058 to 1074 m. Material.—23 mostly decorticated specimens. Discussion.—Acmaea submesidia n. sp. 1s curiously quite distinct from Acmaea n. sp. of Zinsmeister (1990, fig. 1) from the uppermost Lopez de Bertodano Formation, and lacks the crenulate margin present in the older latest Maastrichtian species. Acmaea sub- mesidia n. sp. is smaller, less rounded in outline and has a more anterior apex. Etymology.—Species named from the Greek mesi- dios (equivalent to “‘middle”’) for its subcentrally lo- cated apex. Order CAENOGASTROPODA Cox, 1959 Suborder NEOTAENIOGLOSSA Haller, 1892 Superfamily CERITHIOIDEA Fleming, 1822 Family CERITHIIDAE Fleming, 1822 Genus BITTIUM Gray, 1847 Type species (by subsequent designation, Gray, 1847).—Murex reticulatus Montagu (= Strombiformis reticulatus Da Costa, 1778). Subgenus BITTIUM sensu stricto Bittium (Bittium?) paleonotum, new species Plate 5, figure 5 Cerithium n. sp. Zinsmeister, 1998a, p. 565, fig. 9. Diagnosis.—Moderately sized Bittium species with high spire of at least 8 well-rounded convex whorls, and spire angle of some 22°; sculptural configuration of approximately 25 somewhat clathrose, pustule-bear- ing axial ribs and 7 closely spaced spirals with inter- stitial threads; differs from closely related B. antarc- tonodosum Stilwell and Zinsmeister, 1992, in having a slightly smaller shell, more pronounced clathrose sculpture, more spirals, and more impressed sutures. Description.—Shell medium-sized for genus (~18 mm high), rather thin- to medium-shelled, high-spired turritelliform; spire high, consisting of at least 8 mod- erately rounded, inflated, convex, and slightly com- pressed whorls; sutures impressed; spire whorl infla- tion mostly constant; spire angle ~22°; protoconch de- tails unknown; last whorl incomplete, but moderately inflated and convex; growth lines weakly developed, opisthocyrt; ornamentation of ~25 moderately strong nodulose axial ribs extending from suture to suture and 7 closely and evenly spaced, moderately strong spirals and fine interstitial spiral threads, most abapical rib subsuturally the weakest; sculpture attains a somewhat clathrose pattern with the even crossing of axials and spirals, creating weakly nodulose ribs; aperture details wanting on holotype. Dimensions.—Holotype USNM 511848, height 18.0 mm nearly complete, diameter of last whorl 6 mm. Type.—Holotype USNM 511848. Type locality.—1581. Material.—One specimen. Stratigraphic range.—1165 m. Discussion.—Bittium (Bittium?) paleonotum n. sp. was collected in association with a dense coral colony and is represented solely by the partially decorticated holotype. Despite the imperfect nature of the holotype, the preserved features of this cerithioid gastropod compare well with Bittium Gray, 1847, which is char- acterized by high-spired shells with dominant axial ribs that are overridden by spiral riblets or threads that are swollen into beads, creating a moderately strong clathrose pattern. Bittium (Bittium?) paleonotum n. sp. is apparently closely related to B. antarctonodosum Stilwell and Zinsmeister, 1992 (p. 98, pl. 12, figs. c, d), from Unit V of the La Meseta Formation on Sey- mour Island, differing in having a slightly smaller shell, fewer spirals, and slightly less impressed sutures. The clathrose sculpture is stronger in B. paleonotum n. sp. Although the subgenus is in question, B. (B.?) paleonotum n. sp. is strikingly similar to many extant North American species of the genus (see Abbott, 1974, pp. 106-107, figs. 1012-1031). We know of no other Paleocene species of the genus in the Southern Hemisphere apart from B. (B.?) paleonotum n. sp. Etymology.—Species named from its early occur- rence in the fossil record of Antarctica and from the Greek notos (equivalent to “‘south’’). Subgenus ZEBITTIUM Finlay, 1927 Type species (by original designation).—Cerithium exilis Hutton, 1873. Discussion.—The presence of Bittium (Zebittium) in the Sobral Formation of Seymour extends the range from the middle Eocene of Antarctica and New Zea- land (Stilwell and Zinsmeister, 1992) to the earliest Paleocene. Bittium (Zebittium) is rather common today in shallow to deep (up to 260 m) New Zealand waters (Powell, 1979, p. 132). Bittium (Zebittium) brooksi, new species Plate 5, figures 11—15 Diagnosis.—Moderately sized, high-spired Bittium (Zebittium) with a spire of 6 convex whorls, orna- 28 BULLETIN 367 mented with 12—13 sinuous axial ribs and 6—7 spiral threads, that create weak clathrose pattern, but axials still stronger than spirals; aperture ovate to subrhom- boid with poorly developed canal; differs from Recent type species, B. (Z.) exile (Hutton, 1873), in having less impressed sutures, more spirals, and rounded, op- isthocyrt-trending axials. Description.—Shell average-sized for genus, but small for family (~6.5 mm high), moderately robust, high-spired turritelliform; spire relatively high with at least 6 moderately convex, moderately compressed, well-rounded whorls; spire angle approximately 27°; whorl inflation gradual from early teleoconch whorls to last whorl; sutures impressed; protoconch details eroded in available material; last whorl slightly inflat- ed, ornamented with 12—13 poorly developed, sinuous axial ribs with an apex situated midway on the last whorl at maximum diameter or outer periphery, and ~13 narrowly and semi-equally spaced spiral threads; adapical slope on last whorl steep, short; axials on last whorl weaker than on teleoconch whorls; growth lines weak and strongly opisthocyrt; teleoconch whorls with 6-7 spiral threads, including sutural and subsutural ones, and opisthocyrt-trending axials; the crossing of axials and spiral create a weakly clathrose pattern of poorly developed nodulose ribs; basal constriction generally gradual: aperture small, ovate to subrhom- boid-shaped, with a poorly developed and very weak notch; columella smooth, short, concave; outer lip thin. Dimensions.—Holotype USNM 511849, height 4.5 mm incomplete, diameter of last whorl 2.25 mm; para- type USNM 511850, height 4.5 mm incomplete, di- ameter of last whorl ~2.3 mm; paratype USNM 511851, diameter of last whorl (apertural view) ~2.25 mm; paratype USNM 511852, height of shell 4.0 mm incomplete (showing aperture and sectioned whorls); paratype USNM 511853, height of spire fragment 3.5 mm; paratype USNM 511910, length of block with many specimens, ~68 mm. Types.—Holotype USNM_ 511849; paratypes USNM 511910, 511850—511853. Type locality.—1535 (type locality), 1537. Material.—Several hundred mostly incomplete specimens. Stratigraphic distribution.—1078 to 1099 m. Discussion.—Bittium (Zebittium) brooksi n. sp. from the Sobral Formation is not only the earliest member of this Austral cerithiid group, but is also the most abundant of Antarctic Paleocene mollusks with dense nearly monotypic concentrations of these gas- tropods present at Loc. 1535. As the minute shell of B. (Z.) brooksi is rather fragile, no complete specimen with protoconch preserved is available for study. How- ever, enough characters are preserved in the type ma- terial to enable us to easily differentiate this early spe- cies with other members of the group. Bittium (Zebit- tium) brooksi 1s a distinct member of this subgenus, as the axial ribs are generally just slightly more de- veloped than the spirals, which is generally not the case in most species of Bittium (Zebittium), in which the spirals tend to dominate the axials resulting in a relatively weaker or obsolete nodulation (Powell, 1979p. 132): The Recent type species, B. (Z.) exile (Hutton, 1873) (p. 27; Powell, 1979, p. 132, fig. 32-1) is strikingly similar to B. (Z.) brooksi n. sp., and differs predomi- nantly in whorl shape and minor sculptural differences. Bittium (Zebittium) brooksi is slightly larger with less impressed sutures and has more spirals that are also less nodulose, compared to B. (Z.) exile. The whorl outline of B. (Z.) brooksi is more reminiscent of the Recent New Zealand (Three Kings Islands) species, B. (Z.) editum (Powell, 1930) (see Powell, 1979, p. 132, pl. 29, fig. 15), with a steep subsutural adapical slope, but the axials in the Antarctic species are more pro- nounced and opisthocyrt. The only other Antarctic species of Bittium (Zebit- tium), B. (Z.) granchii Stilwell and Zinsmeister, 1992 (p. 98-99, pl. 12, figs. 1, m), from Unit V of the La Meseta Formation, is quite distinct from, and probably not closely related to, Z. (B.) brooksi, as the Sobral Formation species is much smaller with more but weaker spirals, and has more impressed sutures. A lin- eage from B. (Z.) brooksi to B. (Z.) granchii is un- likely. Etymology.—Species named for Velma May Brooks Paris for her continued support of WJZ over the years. Family TURRITELLIDAE Woodward, 1851 Subfamily TURRITELLINAE Woodward, 1851 Genus TURRITELLA Lamarck, 1799, p. 74 Type species (by monotypy).—Turbo terebra Lin- naeus, 1758. Subgenus HAUSTATOR Montfort, 1810 Type species (by original designation).—Haustator gallicus Montfort, 1810 (= Turritella imbricataria La- marck, 1804). Discussion.—Genus-level systematics and nomen- clature in turritellines are as yet unresolved and in a state of flux (Allmon, 1996). We have therefore chosen to use the generic name Turritella s.1. Only one spec- imen of a turritelline was collected from the Sobral Formation and it is incomplete. This specimen, USNM 511854, has characteristic features of generally flat- tened to very gently convex and solid whorls, weakly impressed sutures, and strong spiral sculpture, similar EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 29 to Turritella (Haustator), type species Turritella (Haustator) gallicus (Montfort, 1810), but it is as- signed to Turritella (Haustator?) until better material is obtained. Turritella (Haustator?) parisi, new species Plate 5, figure 17 Turritella n. sp. Zinsmeister, 1998a, p. 565, fig. 9. Diagnosis.—Moderately sized turritellid with acute spire of more than 5 gently convex to nearly subquad- rate whorls, ornamented with dominantly spiral sculp- ture of 5 primary cords with excavated and gently wavy interspaces and a weak axial, nodulose compo- nent in early whorls; growth lines shallowly opistho- cyrt with apex of sinus in lower third of whorls; differs from Eocene type species, 7. (H.) imbricataria La- marck, in having a shorter spire, slightly stronger spi- ral cords, and broader opisthocyrt growth lines. Description.—Shell medium-sized for family, mod- erately thick, moderately high-spired turritelliform; spire moderately high to high of more than 5 subquad- rate, gently convex to nearly flush whorls; spire angle acute at approximately 23°; protoconch unknown; su- tures very slight impressed to almost flush; last whorl incomplete; spire whorls sculptured with 5 pronounced primary spiral cords that have slightly wavy, excavated interspaces, generally weakening only slightly adapi- cally; in early whorls a weakly nodulose axial com- ponent of poorly developed opisthocyrt-trending growth elements that become weaker on younger whorls where there are very fine growth lines; apex of growth lines on lower third of each whorl; base with rapid constriction that is nearly flat to gently convex: aperture incomplete, but remnants indicate a subquad- rate outline. Dimensions.—Holotype USNM 511854, height 16.0 mm incomplete, diameter of last whorl 7.5 mm. Type.—Holotype USNM 511854. Type locality.—1716. Material.—Holotype. Stratigraphic range.—1066 m. Discussion.—The whorl profile, outline and sculp- ture of this new Antarctic turritellid, named here Tur- ritella (Haustator?) parisi, matches coeval and slightly younger Eocene species of Turritella (Haustator), type species 7. (H.) imbricataria Lamarck, 1804 (p. 216; Montfort, 1810, pp. 182-184, full-page woodcut (p. 182); Cossmann, 1888, p. 300; see Wenz, 1939, pp. 653-654, fig. 1860), from the middle Eocene of France, in having a relatively high-spired shell with subquadrate to gently convex, nearly flush, whorls. The sutures are, indeed, only weakly impressed to al- most flush in 7. (H.) imbricataria. The Antarctic spe- cies has these features and also the prominent spiral cords found in the type, but with respect to the growth lines the apex of the sinus is shallower than the type. Few other Paleocene taxa compare well with 7. (H.?) parisi n. sp. apart from the highly variable spe- cies T. (H.) nigeriensis Adegoke, 1977 (pp. 95—96, pl. 16, especially fig. 7) from the Paleocene of Nigeria, but the Antarctic species has fewer and comparatively weaker spiral cords and less impressed sutures. There are no other related Antarctic turritellids. Etymology.—Species named in honor of Dr. David Paris MD for his untiring support of WJZ during the early years of his career. Subfamily PAREORINAE Finlay and Marwick, 1937 Genus MESALIA Gray, 1847 Type species. (by original designation).—Cerithium mesal Adanson (= Turritella brevialis Lamarck, 1822). Mesalia virginiae, new species Plate 5, figures 6—10 Mesalia n. sp. B, Zinsmeister et al., 1989, p. 734, fig. 3. Diagnosis.—Moderately sized, high-spired, rather delicate thin-shelled Mesalia with at least 7 strongly unicarinate whorls, ornamented with 3—4 spiral cords and weaker, beaded, spiral threads on upper adapical half, strongest cord at peripheral angulation, becoming weaker abapically; growth lines broadly opisthocyrt; canal distinct, narrow and small, spout-like, twisted obliquely and abaxially. Description.—Shell medium-sized for genus (less than 30 mm high), relatively thin-walled, broadly high-spired of at least 7 strongly carinate, subquadrate, compressed whorls; spire angle 33°; protoconch in- complete, but apparently polygyrate of smooth, round- ed whorls; whorl inflation moderately rapid; sutures impressed; last whorl slightly to moderately inflated, strongly unicarinate with only spiral sculpture of 6 marked spiral cords on lower abapical half of shell, the strongest cord at peripheral angulation, and weak, beaded, spiral threads on short steep, weakly concave, adapical ramp; teleoconch whorls ornamented with weak spiral threads on upper halves of whorls and 3 to 4 moderately strong primary cords, cord at angu- lation the strongest, and quite weak secondary spiral threads; adapical slopes on teleoconch whorls steep, short; growth lines poorly developed, weak, closely spaced, broadly opisthocyrt; basal constriction rapid, culminating in a short, narrow, twisted, abaxially- trending, spout-like canal; aperture broadly D-shaped; 30 BULLETIN 367 columella short, mostly straight with narrow callus; outer lip thin. Dimensions.—Holotype USNM 511855, height 28.0 mm, diameter of last whorl 13.5 mm; paratype USNM 511911, height 21.5 mm, diameter of last whorl 16.5 mm incomplete; paratype USNM 511912, height 29.5 mm, diameter of last whorl 12.5 mm; USNM 511913, length of block of specimens 80.5 mm. Types.—Holotype USNM 511855; paratypes USNM 511911, USNM 511912, USNM 511913. Localities. 497, 746, 1104, 1139, 1548, 1591, 1715 (type). Material.—20 specimens. Stratigraphic range.—1053 to 1375 m. Discussion.—Mesalia 1s recognized in the fossil re- cord of Antarctica for the first time, represented by the relatively rare occurrence of M. virginiae n. sp., except at locality 1139 where it occurs in large numbers. In the Southern Hemisphere, species of Mesalia are an uncommon element of Paleocene faunas. Mesalia vir- giniae n. sp. is easily distinguished from other coeval species in having strongly unicarinate whorls and a short, but distinct, spout-like siphonal canal that is twisted obliquely and abaxially. Mesalia sp. 1 and 2 of Kollmann and Peel (1983, pp. 42—43, figs. 70, 71) from the Paleocene of Greenland have nearly the same outline with a similar spire angle, but the whorls are nearly flush with sculpture of even spiral cords. The canal is not nearly as distinct in the Greenland species. No unicarinate species are present in the Paleocene of Nigeria (Adegoke, 1977), and all have relatively reg- ular spiral sculpture. The Recent African type species, M. brevialis (Lamarck, 1822) (p. 58, not figured; Wenz, 1939, p. 651, fig. 1851; Abbott and Dance, 1983, p. 59, figure upper left corner), has a much high- er spire, more rounded whorl profiles, a more rudi- mentary siphonal canal, and flatter spiral ribs, com- pared to M. virginiae. The phylogeny of M. virginiae is uncertain, as it disappeared from the Antarctic fossil record after the Paleocene. Etymology.—This species is named in honor of Dr. Virginia Ann Paris Zinsmeister for keeping the home fires going during my numerous trips to Seymour Island and for also providing support to JS and AO while they were graduate students at Purdue University. Superfamily STROMBOIDEA Rafinesque, 1815 Family APORRHAIDAE Gray, 1850 Genus STRUTHIOCHENOPUS Zinsmeister and Griffin, 1995 Type species (by original designation).—Perissop- tera nordenskjoldi Steinmann and Wilckens, 1908. Discussion.—Struthiochenopus Zinsmeister and Griffin, 1995, is one of few aporrhaid gastropods that survived the K-T boundary well into the Tertiary with species spanning Campanian to early Miocene time from Antarctica to South America (Chile, Argentina). In Antarctica, the group spans the Campanian to Pa- leocene interval, represented by S. nordenskjoldi (Wilckens) (Campanian), from Snow Hill Island (pos- sibly also Vega and James Ross islands), and S. hurleyi n. sp. (Wilckens, 1910) (latest Maastrichtian to Paleo- cene) of Seymour Island. Struthiochenopus hurleyi, new species Plate 5, figures 18—20; Plate 6, figures 1—6 Perissoptera nordenskjoldi Wilckens, 1910, pp. 83-86, pl. 4, fig. 5 only; Macellari, 1984, pl. 34, figs. 5-8; Zinsmeister and Macel- lari, 1983, fig. B4; Zinsmeister et al., 1989, p. 733, fig. 2, p. 734, fig. 3, p: 736, fig. 6. Aporrhaidae spp. Palamarczuk er al., 1984, p. 401. Struthiochenopus nordenskjoldi (Wilckens). Zinsmeister and Griffin, 1995, pp. 699-700, fig. 3.11-3.19. Description.—Shell medium-sized with moderately low spire consisting of 7 to 8 convex whorls, spire an- gle 45° to 47°; protoconch of 2.5 smooth whorls with faint keel; keel strengthens rapidly becoming sharp on later whorls eventually merging with posterior digita- tion, second less pronounced more abapically keel de- veloped on body whorl, merges with anterior digitation; 20 to 24 weak rounded nodes present on primary keel becoming obsolete on body whorl; shoulder posterior to primary keel flat merging with slightly impressed suture; medial portion of whorl between keels flat to concave; body whorl anterior to secondary keel drawn out into narrow siphon; surface covered with faint nar- row spiral threads; aperture elongated, pyriform with moderately long and straight canal; outer lip expanded into broad moderately thick wing, inclined at about 50° or more to shell axis; moderately broad shallow sinus along posterior margin of wing; primary keel merges with long curved posterior digitation; posterior digita- tion frequently dorsally curved; anterior digitation blunt, anteriorly oriented; posterior margin of wing be- tween posterior digitation and suture thickened; medial apertural surface of wing digitation thickened; inner lip of aperture covered with moderate callus. Dimensions.—USNM_ 405836, height 57.0 mm, width of last whorl without wing 16.0 mm (figured specimen). Types.—Holotype 405857; paratypes USNM 405858, PU783/2. Localities.—9, 447, 497, 783, 1104, 1119, 1131, 1134) 1135, W36s 1137) W148) 16 iso 20s; 1430, 1431, 1433, 1434, 1435, 1442, 1456, 1467, 1479, 1502, 1508; 1505; 1506; 15075 15083 ds10; 15195) 15295 1531, 1532, 15345 W535) 1SsoNalasi: EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 31 ISS Siels485 is 74slisi 7s 1587. 1589) 160i, 1697, 1698, 1699, 1700. Material.—327 specimens. Stratigraphic range.—1037 to 1375 m. Discussion.—Although Zinsmeister and Griffin (1995) referred all of the aporrhaid gastropods figured by Wilckens (1910) to S. nordenskjoldi, it is clear from the examination of Nordenskjold’s material that there are two distinct species. Wilckens’ figures 2, 3, and 4 on plate 4 come from latest Campanian to early Maas- trichtian from Snow Hill Island while figure 5 without the wing is distinct and comes from the Danian of Seymour Island. This confusion stems from the fact that Andersson and Nordenskjold had only crude un- derstanding of the stratigraphic relationships between Snow Hill and Seymour islands and locality informa- tion was limited. Locality data concerning many of the fossils collected by Nordenskjold’s party prior to the arrival of Andersson in 1903 are absent and the strati- graphic horizon from which these fossils were col- lected can only be estimated from the nature of pres- ervation and the supposed track of the field parties to Seymour Island in 1902. It is now known that there are two horizons on Snow Hill and Seymour islands where Struthiochenopus occurs. The specimens referred to as S. nordenskjoldi in Wilckens (1910), figures 2—4, and Zinsmeister and Griffin (1995), figures 3.9 and 3.10, are from Snow Hill Island, where they typically occur as casts and molds in dark reddish brown concretions. Wilckens’s figure 3 actually shows a steinkern of S. nordenskjoldi in one of these concretions. His figures 2 and 4 are casts made from these steinkerns. It is interesting to note that the locality where this material was collected is only a short distance from Nordenskjold’s hut on Snow Hill Island and is probably the first fossil local- ity that Nordenskjold discovered on his arrival on the island. The two specimens figured by Zinsmeister and Griffin are latex molds from concretions collected by Zinsmeister from near Nordenskjold’s hut in a visit to Snow Hill Island in 1981. Struthiochenopus hurleyi n. sp., Wilckens’s figure 5 and Zinsmeister and Griffin’s figures 3.11—3.19, is restricted to the uppermost Maas- trichtian level of unit 9 of the Lopez de Bertodano Formation and the Danian unit 10 of the Lopez de Bertodano Formation and the Sobral Formation. Although Struthiochenopus hurleyi and S. norden- skjoldi are closely related, S. hurleyi is about two-thirds the size of S. nordenskjoldi. The shoulder of S$. norden- skjoldi is typically concave between the primary keel and the suture. In addition, the siphonal canal of S. nordenskjoldi is long and straight compared to the rel- atively shorter and curved siphon of S. hurleyi. It is possible that Rostellaria patagonensis von ther- ing, 1903 (p. 209, 221, not figured: 1904, pp. 13-14, fig. 11; 1907, p. 29), and R. chubutensis von Thering, 1903 (p. 220, pl. 2, fig. 17; 1907, p. 29), from the Paleocene Roca and Salamanca formations of Pata- gonia belong to Struthiochenopus, but the poor pres- ervation of these taxa prevents an accurate assessment. The mostly smooth unicarinate teleoconch whorls that are ornamented with poorly developed axial ribs are, however, consistent with Struthiochenopus. The disjunct stratigraphic distribution of Struthioch- enopus on Snow Hill and Seymour islands is a bit surprising. Although the genus is absent throughout the Maastrichtian on Seymour Island except for its re- appearance in the uppermost part of unit 9 just below the K-T boundary, Austroaporrhais, another genus of aporrhaid gastropod, is extremely abundant throughout the late Maastrichtian, but disappears prior to the re- appearance of Struthiochenopus. Immediately follow- ing the K-T extinction, S. hurleyi becomes very abun- dant and remains a prominent element in the Danian molluscan assemblage on Seymour Island. Etymology.—This species 1s named in honor of phe- nomenal photographer, Frank Hurley, on Ernst Shack- leton’s ill-fated attempt to cross the continent of Ant- arctica. The photographs that Hurley took during the expedition are considered to be some of the finest ever taken in Antarctica. Family STRUTHIOLARIIDAE Fischer, 1887 Genus ANTARCTODARWINELLA Zinsmeister, 1976 Type species (by original designation).—Antarcto- darwinella ellioti Zinsmeister, 1976. Discussion.—Presence of Antarctodarwinella in the Sobral Formation extends the stratigraphic range of this endemic characteristic struthiolariid into the early Paleocene. The heavily callused and globose nature of Antarctodarwinella is reminiscent of only one other struthiolariid gastropod, Conchothyra, recorded from the Campanian (or possibly Santonian) to Danian, of New Zealand. Although beyond the scope of this pa- per, the relationships between species of Conchothyra, Antarctodarwinella, and Australian Tylospira (espe- cially early forms such as 7. glomerata Darragh, 1991, from the early Miocene) require further assessment and clarification. The absence of Cretaceous struthio- lariids in the fossil record of Antarctica suggests that its dispersal from New Zealand was associated with the population of the shelf faunas along the southern Pacific margin during the recovery stage following the K-T boundary event. oS) tN Antarctodarwinella austerocallosa, new species Plate 6, figures 7—15 Conchothyra or Antarctodarwinella sp. Palamarczuk et al., 1984, p. 401. Antarctodarminella n. sp. Stilwell, 2002, p. 404. Diagnosis.—Medium-sized, robust, subglobose An- tarctodarwinella with at least 4 weakly angled to gent- ly rounded whorls; last whorl bicarinate with strongly projecting wing, ornamented with poorly developed tubercle development, slightly stronger on adapical keel: last whorl with sinuous growth rugae, stronger near wing and more spaced on older whorls; adapical or posterior sinus angle approximately 52.5°; callus de- velopment pronounced, partially enveloping spire, but only to penultimate whorl; distinguished from type species, A. ellioti Zinsmeister, 1976, in having a nar- rower less globose shell, stronger tubercle develop- ment, higher spire, and broader aperture. Description.—Shell moderately sized for genus and family (up to 35 mm high), semi-globose, thick and robust, low to moderately elevated spire of at least 4 compressed, weakly angled to gently convex, strongly ornamented whorls; protoconch paucispiral, smooth, only partially preserved in available material; spire an- gle variable from approximately 62° to just over 80°; whorl inflation rapid, especially from penultimate to last whorl; sutures encroaching on succeeding whorls, moderately declivous; last whorl capacious, well-in- flated with diameter of last whorl just under height of shell: last whorl bicarinate with projected wing, strongly ornamented with rugose, sinuous, varix-like growth increments, posterior or adapical sinus angle ~52.5 °; moderately spaced, rather blunt, axially ex- tending tubercles, present only on poorly developed carinae that are 5 mm apart, and with interspaces smooth; growth increments closer spaced on_ last whorl, especially more bunched on wing, compared to more spaced ones on older whorls; last whorl with distinct digitation, that is partially truncated to weakly convex and rounded on the distal portion of wing abaxially; spire whorls with sparse sculpture apart from 10-12 weakly developed, only slightly axially extending, tubercles that commence on antepenulti- mate whorl; last whorl with extensive callus that en- croaches on earlier whorls, extending completely over penultimate whorl, but does not completely envelop the spire, still creating a subglobose outline; fasciole forms a moderately developed low ridge on the ab- apical part of the last whorl; aperture moderately small, sublenticular to narrowly subovate with distinct raised callus pad extending to the parietal region, be- coming slightly narrower at poorly developed canal; BULLETIN 367 columella very gently curved, especially in the parietal area; outer lip thickened. Dimensions.—Holotype USNM 511856, height 35.5 mm, diameter of last whorl including wing 30.5 mm; paratype USNM 511857, height 32.5 mm, diameter of last whorl 22.5 mm (without wing preserved); para- type USNM 511858, height 33.25 mm, diameter of last whorl 22.5 mm; paratype USNM 511859, height 30.5 mm, most of last whorl incomplete; paratype USNM 511914, external mold height of specimen 34.5 mm, height of concretion 61.0 mm. Types.—Holotype USNM 511856; paratypes USNM 511858, USNM 511859, USNM 511914. Localities. —497, 1434 (type). Material.—Four moderately well-preserved speci- mens and one external mold. Stratigraphic distribution.—1166 to 1369 m. Discussion.—The presence of a species of Antarc- todarwinella, herein named A. austerocallosa n. sp., in the Paleocene of Antarctica not only extends the stratigraphic range from the Eocene to the Paleocene, but also presents new data on the phylogeny of this biostratigraphically significant group. Although only three species of Antarctodarwinella have been record- ed, A. austerocallosa n. sp., A. ellioti Zinsmeister, 1976 (Units II, Il only, La Meseta Formation), and A. nordenskjoldi (Wilckens, 1911) (Units HI—V, La Mes- eta Formation), the phylogeny of the genus is curi- ously not at all clear-cut, as the oldest Paleocene spe- cies, A. austerocallosa n. sp., is enigmatically much more similar to the youngest species, A. nordenskjoldi. The growth line symmetry is nearly identical in all three species. However, the adapical or posterior sinus angle (PSA) is similar in A. austerocallosa and A. nor- denskjoldi at just over 50°, whereas in the oldest Eo- cene species the angle is approximately 30°. Zins- meister and Camacho (1980, pp. 3—4) presented evi- dence of a large increase in the PSA through time in Antarctodarwinella, but measurements on the new Pa- leocene species falsifies this perceived trend. Antarc- todarwinella ellioti is larger and much more globose with a lower spire, compared to both A. austerocallosa and A. nordenskjoldi. The extensive callus develop- ment in A. ellioti is more reminiscent of Conchothyra parasitica Hutton, 1877, from the Santonian?—Cam- panian, and C. australis (Marshall, 1916) of New Zea- land, in which the callus nearly envelops the spire. It seems likely that A. nordenskjoldi was derived from A. austerocallosa, as growth lines and sculpture are comparable, except for the more developed wing in A. austerocallosa. Also, the last whorl in A. austerocal- losa is more strongly bicarinate with a marginally sharper abapical keel and the labial callus less devel- oped than in A. nordenskjoldi. The disparity in mor- EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. phology between the three species of Antarctodarwi- nella indicates that the fossil record of this group is far from complete, and other intermediate forms prob- ably existed, of which we have no fossil record. In- deed, no Antarctodarwinella-like struthiolariids are re- corded from upper Paleocene to lower Eocene depos- its, as there is a paucity of deposits of this age in the Southern Hemisphere. Etymology.—Species named from the Latin callosus (equivalent to “hard skin, callus”) and Latin auster (equivalent to “‘south’’?) for its heavily callused shell and endemic presence in Antarctica. Superfamily VANIKOROIDEA Gray, 1840 Family VANIKORIDAE Gray, 1840 Genus VANIKOROPSIS Meek, 1876 Type species (by original designation).—WNatica tou- meyana Meek and Hayden, 1856. Discussion.—Vanikoropsis is one of the oldest Cre- taceous gastropods with records extending back to the Barremian—Aptian of Japan (Tracey ef al., 1993, p. 148). Vanikoropsis had a wide distribution during the Cretaceous with reports of the genus from Europe, West India, North America, Australia, New Zealand and Antarctica (see Wenz, 1938; Fricker, 1999). The genus survived the K-T boundary extinction event and apparently inhabited northern and southern polar re- gions only (Kollmann and Peel, 1983; Zinsmeister er al., 1989). Vanikoropsis arktowskiana (Wilckens, 1910) Plate 6, figures 16-19 Eunaticina? arktowskiana Wilckens, 1910, pp. 78-80, pl. 3, figs. 29a, b, pl. 4, figs. 17, 18. Eunaticina arctowskiana Wilckens. Macellari, 1984, pl. 34, figs. 11— 12, pl. 35, fig. 11, error pro V. arktowskiana; Stilwell and Zins- meister, 1987a, p. 9, error pro V. arktowskiana; Stilwell and Zins- meister, 1987b, p. 8, error pro V. arktowskiana. Eunaticina arctowskiana Wilckens. Zinsmeister et al., 1989, p. 733, fig. 2, p. 734, fig. 3, p. 736, fig. 6, error pro V. arktowskiana; Stilwell, 1994, p. 661; Zinsmeister, 1998a, p. 565, fig. 9, error pro V. arktowskiana. Vanikoropsis. n. sp. Fricker, 1999, pp. 146-152, pl. 3, figs. 5-10. V. arctowskiana (Wilckens). Fricker, 1999, pp. 153-155, pl. 3, figs. 11, 12, pl. 4, figs. 1-3, error pro V. arktowskiana (Wilckens, 1910). Dimensions. —USNM 511860, height 44.5 mm, di- ameter of last whorl 36.5 mm; USNM 511861, height 34.0 mm, diameter of last whorl 29.5 mm. Types.—Mo 1330, Mo 1339, Mo. 1340. Localities.—9, 496, 1134, 1135, 1205, 1414, 1430, 1431, 1432, 1434, 1505, 1506, 1507, 1508, 1510, 1548, 1589, 1596, 1601, 1698, 1700. Material.—98 specimens. Stratigraphic range.—900 to 1201 m. eS) es) Discussion.—The abundant, characteristic natici- form gastropod Eunaticina? arktowskiana Wilckens, 1910 (p. 78, pl. 3, fig. 29a, b, pl. 4, figs. 17, 18), from the latest Cretaceous to Danian of the James Ross Is- land Group (recorded from Snow Hill, Seymour and James Ross islands), was divided recently by Fricker (1999, pp. 145-155) into two species, one new. In our opinion, this division may not be warranted, especially given the variable nature of Vanikoropsis (see Sohl, 1967; Erickson, 1974). A scatter diagram of height versus diameter provided by Fricker (1999, p. 152) does not yield evidence for such a separation of V. arktowskiana and, for example, the figured specimen of Vanikoropsis n. sp. (see pl. 3, fig. 3a, b) can hardly be distinguished from V. arktowskiana depicted on the same plate (see fig. 9a, b). The sculptural configuration of V. arktowskiana is diverse with differences from individual to individual of strength, width, spacing, and number of spirals. The convexity of the whorl out- line is also variable in the species, as is the expanded nature of the outer lip. Vanikoropsis arktowskiana is one of the longest ranging species in Antarctica with records extending from probably Campanian time to at least the early Danian, crossing the K-T boundary unscathed. We can cite no differences in Paleocene forms, compared with their Cretaceous counterparts. The affinity of probable older Antarctic forms such as Vanikoropsis? sp. of Thomson (1971) from Alexander Island is uncertain, as the material is poorly preserved. Superfamily NATICOIDEA Gray, 1840 Family NATICIDAE Gray, 1840 Subfamily POLINICINAE Gray, 1847 Genus AMAUROPSIS Morch, 1857, p. 81 Type species (by subsequent designation, Dall, 1909).—Natica helicoides Johnston, 1835 (= Nerita islandica Gmelin, 1791). Discussion.—Amauropsis 1s one of few gastropods with a stratigraphic range of Paleocene to Recent in Antarctica (see extant species described by Dell, 1990). Of note, Amauropsis is not present in the Eo- cene La Meseta Formation. Dell (1990, pp. 139-140) could see no evidence to separate the Arctic and Ant- arctic forms of Amauropsis, despite the absence of a channeled suture in Antarctic species, and advised that the concept of Amauropsis be expanded rather than to divide the northern and southern forms when the state of present knowledge of the significance of sutural dif- ferences has not been adequately evaluated. 34 BULLETIN 367 Amauropsis notoleptos, new species Plate 6, figures 20—22 Diagnosis.—Early, small Amauropsis with a mod- erately high spire of at least three convex whorls, and spire angle of ~92°; no sculpture as shell polished and smooth apart from weak prosocline growth lines and equally weak, numerous microscopic growth lines; umbilicus poorly developed; labial callus well raised, but rather narrow extending to parietal area; differs from closely related A. rossiana Smith, 1907, in hay- ing a much smaller shell, slightly less developed spiral sculpture of microscopic threads, a more raised callus, and slightly shallower umbilicus. Description.—Shell relatively small for genus (less than 10 mm high), thin, polished, strong, moderately high-spired naticiform, umbilicate; ratio of height to diameter of last whorl 1.25:1; spire moderately high, consisting of at least three convex whorls with narrow- ly channeled sutures or subsutural furrows; spire angle ~92°; apical whorls low, paucispiral, worn in available material; inflation rapid, especially from penultimate to last whorl; last whorl moderately inflated, convex, smooth apart from weak prosocline growth lines and weak microscopic spiral threads; sculpture on penul- timate whorls similar of very weak growth lines and spirals; aperture holostomatous, moderately ovate, open; columella gently concave; labium with raised, well-defined, moderately narrow callus; outer lip thin. Dimensions.—Holotype USNM 511862, height 8.0 mm, diameter of last whorl 7.0 mm; paratype USNM 511863, height 6.5 mm, diameter of last whorl 5.0 mm. Types.—Holotype USNM 511862; paratype USNM 511863. Localities.—1519, 1531 (type). Material.—Two specimens and other fragments. Stratigraphic distribution.—1053 to 1073 m. Discussion.—Amauropsis notoleptos n. sp. is the oldest record of the genus in Antarctica and the only species known from the Paleogene. A. notoleptos is apparently allied to and is probably the ancestor to living Antarctic species such as A. rossiana Smith, 1907 (p. 5, pl. 1, figs. 6, 6a; Dell, 1990, p. 140, figs. 247, 276), and A. powelli Dell, 1990 (p. 144, figs. 246, 268), but differs in its much smaller size and narrower, slightly taller spire. The aperture and callus of A. ros- siana 1s strikingly similar to A. notoleptos, but the Pa- leocene species has a marginally more developed um- bilicus. The Recent (also known as fossil, but ages unknown) type species, A. islandica (Gmelin, 1791) (p. 3675; Wenz, 1938-1944, p. 1035, fig. 2965; Mar- incovich, 1977, pp. 217-218, pl. 17, figs. 1-4, pl. 22, fig. 1, text-fig. 12), is largely a magnified version of and is very similar to A. notoleptos n. sp., and differs in having a much larger shell with a higher spire and more distinct prosocline growth lines. Other Paleocene species of Amauropsis, such as A. meierensis Zins- meister, 1983 (pp. 1292-1293, fig. 2L, M) and A. mar- tinezensis Dickerson, 1914 (p. 142, pl. 13, fig. 4a, b; Marincovich, 1977, pp. 221-222; pl. 17, figs. 5—10), from the Paleocene of Western North America have higher spires and much larger shells, compared to A. notoleptos, and are not closely related. The origin of A. notoleptos is uncertain, given the patchy strati- graphic distribution of the group in the earliest Tertia- ry. Etymology.—Species named from the Greek word notos (equivalent to “‘south’?) and Greek word /eptos (equivalent to “fine, small”) for its endemic Antarctic occurrence and small size for the genus. Genus EUSPIRA Agassiz in J. Sowerby, 1837 Type species (by subsequent designation, Bucquoy, Dautzenberg, and Dollfus, 1883)—Natica glaucinoides J. Sowerby, 1812 (non Deshayes, 1832) (= Natica la- bellata Lamarck, 1804) (Kabat, 1991, p. 429). Euspira antarctidia, new species Plate 7, figures 7-10 Diagnosis.—Relatively small but robust Euspira with nearly 1:1 ratio of height to diameter of last whorl; weakly channeled sutures, and dome-like pro- toconch of no more than 2 whorls; no sculpture, just weak prosocline growth lines and microscopic spirals; umbilicus moderately developed; funicle present; ap- erture D-shaped to broadly oval-shaped; differs from closely related Antarctic species, Euspira n. sp. of Fricker (1999), in being minute in comparison, with weaker growth lines, a funicle, and a more D-shaped aperture. Description.—Small-to medium-sized for genus (up to 13.0 mm high), moderately high-spired, robust, glo- bose naticiform, umbilicate; spire of at least 2 small, weakly inflated, convex whorls with weakly channeled sutures; ratio of height to diameter of last whorl just over |.1:1; protoconch paucispiral, dome-like, smooth, slightly covered in matrix on holotype; spire angle ob- tuse of approximately 112.5°; whorl inflation quite rap- id, especially from penultimate to last whorl; last whorl greatly inflated, with faint, weak microscopic threads and prosocline growth lines only; teleoconch whorls similarly smooth with only prosocline growth lines; aperture large, holostomatous; broadly ovate to D-shaped; umbilicus moderately deep; columella dis- tinctly curved with distinct but rather thin funicle; pa- rietal region with thin glaze; outer lip thin. Dimensions.—Holotype USNM 511864, height 13.0 EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL ef al. mm, diameter of last whorl 11.5 mm; paratype USNM 511865, height 7.0 mm, diameter of last whorl 6.5 mm; paratype USNM 511866, height 6.0 mm, diam- eter of last whorl 5.5 mm. Types.—Holotype USNM 511864; paratypes USNM 511865, USNM 511866. Localities.—1519 (type), 1535, 1538. Material.—Seven specimens. Stratigraphic range.—1072 to 1130 m. Discussion.—Euspira is recognized in Antarctic Pa- leocene deposits for the first time, previously recorded from the latest Cretaceous (Fricker, 1999) and mid- Eocene (Stilwell, 2000). Euspira antarctidia n. sp., de- scribed herein from the Sobral Formation, is closely related to Euspira n. sp. of Fricker (1999, pp. 158— 161, pl. 4, figs. 4a, b, 5a, b) from the Maastrichtian (perhaps even older record of Campanian, also) of the Lopez de Bertodano Formation, but is comparatively small to moderate in size with more defined prosocline growth lines, a slightly more compressed last whorl, a more D-shaped aperture, and a less open umbilicus. Euspira bohatyi Stilwell, 2000 (p. 303, pl. 8, figs. a—c) from the middle Eocene of McMurdo Sound, East Antarctica, has a much larger shell, a more compressed last whorl, stronger prosocline growth lines, and a much wider umbilicus. The European Eocene type species, E. labellata (Lamarck, 1804) (see Brown, 1849, p. 89 (error p. 99 in index), pl. 43, figs. 30-31, Natica glaucinoides, Wenz, 1941, p. 1042, fig. 2986), is also quite comparable to E. antarctidia, but differs again in its much larger size, a more inflated spire, and stronger growth lines. Other Austral Paleocene species are apparently only distantly related to E. antarctidia n. sp.; these include E. fyfei (Marwick, 1924) from South Island, New Zea- land, Euspira sp. cf. E. pueyrredonensis (Stanton, 1901) of Griffin and Hiinicken (1994) from south- western Patagonia, and E. saxosulensis Darragh, 1997, from Victoria, Australia. These records indicate that the genus was well distributed and established in Southern Hemisphere Paleocene shallow waters. Etymology.—Species named from the Latin dimin- utive prefix -idium and for its occurrence in Antarctica. Superfamily TONNOIDEA Suter, 1913 Family RANELLIDAE Gray, 1854 Subfamily CYMATIINAE? Iredale, 1913 Genus ANTARCTIRANELLA, new genus Type species (by original designation).—Antarctir- anella tesella n. gen. n. sp. Diagnosis.—Moderately high-spired ranelliform or fusiform shell with highly ornamented shell of can- oS) n cellate sculpture that approaches a tesselate or ““check- er-board” pattern on the central part of last whorl and penultimate whorl with rounded nodes at the intersec- tion of spiral and axial elements; spiral ornamentation of two strong carinae and spiral cords; outer lip broken on available material, but preserved sections indicate a definite flare or varix; inner lip with moderately broad callus, concave; aperture broadly ovate; inner labrum with furrows corresponding to spiral elements; siphonal canal moderately long, slightly twisted, nar- rowly notched. Discussion.—Antarctiranella n. gen. is erected here- in for an enigmatic Paleocene Antarctic gastropod with a moderately twisted siphonal canal, flared outer lip and shell form reminiscent of groups within the Ra- nellidae. Only one specimen of this gastropod was available for study, but a new species described by Fricker (1999) from the Lopez de Bertodano Forma- tion of Seymour Island is probably congeneric if not perhaps conspecific as well, but the penultimate whorl is more convex and the sutures more impressed. Frick- er (1999) (pp. 175-177) considered the Maastrichtian Antarctic species to be an aberrant member of the Ra- nellidae as it does not appear to have either a definite varix, columellar plications, or a rugose inner lip callus compared with many ranellid gastropods. Fricker sug- gested that a possible relationship to Buccinidae can- not be discounted, but we suggest that the overall form and flared outer lip is more indicative of Ranellidae. Further, Fricker was apparently unaware of a specimen collected from the Paleocene Sobral Formation of Sey- mour Island. This individual has an outer lip that can be described as a definite varix. There is no other member of the Ranellidae that approaches this new group apart from Cymatium s.l. (A. Beu, personal communication, 2000), so it is highly likely that An- tarctiranella n. gen. was short-lived and became ex- tinct sometime during the Paleocene. Etymology.—Named based on its sole early pres- ence in Antarctica and for its relationship to Ranelli- dae. Antarctiranella tessela, new species Plate 7, figures 5, 6 Diagnosis.—As for genus. Description.—Shell moderately large for family (slightly more than 38 mm high), robust, moderately thick-shelled, ranelliform to fusiform: spire moderately high of more than 2 unicarinate, nearly quadrate, slightly convex whorls, about a third of total height of shell; whorl inflation rapid from penultimate to last whorl; spire angle approximately 66.5°; protoconch unknown; suture barely impressed, slightly clasping, 36 BULLETIN 367 last whorl wrapping around noded axials of penulti- mate whorl; sculpture elaborate of tesselate or ““check- er-board”’ pattern of cancellate spiral ribs and equally strong axials, especially centrally on last whorl, bear- ing 10-11 axially aligned nodes on the two central carina, which are concave between; last whorl with more than 17 strong, but unequally developed spiral cords and many microscopic interstitial threads; last whorl broadly convex with 10-11 axials and nodes, slightly concave between carinas; sutural ramp mod- erately steep, gently concave, merging with carina; ax- ials on penultimate whorl extend from adapical carina abapically to suture; some 12 nodes on penultimate whorl; axials on penultimate whorl not aligned with those on last whorl; growth lines poorly defined; base of last whorl strongly contracted to moderately short, slightly twisted, narrowly notched canal; aperture broadly ovate with narrow channels corresponding to carina on last whorl; labium with moderately narrow callus; columella seemingly smooth, concave; outer lip flared abaxially into thickened varix, smooth internal- ly. Dimensions.—Holotype USNM 511867, height slightly more than 38.0 mm if complete, diameter of last whorl 29.0 mm. Type.—Holotype USNM 511867. Type locality.—1431. Material.—Holotype Stratigraphic range.—1144 m. Discussion.—Antarctiranella tessela n. gen. n. sp. represents an early member of the Ranellidae that has no other coeval or older Late Cretaceous relatives. It is probably a short-lived taxon that evolved during the K-T boundary marine revolution that became extinct sometime during the Paleocene. As reviewed by Beu (1988), the oldest recorded ranellid is Turonian in age, Sassia kanabensis (Stanton, 1893) from the Western Interior of North America, and most of the six record- ed species are Maastrichtian. None of these approach the new Antarctic Paleocene species. Paleocene mem- bers of the group are rare and consist of Gyrineum? judithae Zinsmeister, 1983, from the Danian, Sassia sp. of Darragh (1997, p. 74, fig. 3G, H) from the mid- Paleocene of southeastern Australia, and Ranella louellae Beu, 1988, from the late Paleocene of Cali- fornia. Ranellids described by Kollmann and Peel (1983) from the Paleocene of Greenland do not belong in this family (A. Beu, personal communication, 2000). Etymology.—Species named from the Latin fresella (equivalent to “inlaid with small, square stones, check- ered”) for its checkered sculptural configuration of ax- ials and spirals on the last and penultimate whorls. Superfamily EULIMOIDEA Philippi, 1853 Family EULIMIDAE Philippi, 1853 Genus MELANELLA Bowdich, 1822, p. 120 Type species (by monotypy).—Melanella dufresnei Bowdich, 1822 (non dufresnii, error, Abbott, 1974, p. 125): Discussion.—The Paleocene distribution of this eu- limid is extended to Antarctica, previously recorded from the Paleocene of New Zealand (Finlay and Mar- wick, 1937), and Eocene to Recent of Europe, North Africa, South India, Japan, West Indies, and North and South America (Wenz, 1940, p. 835). Balcis Leach, 1847, is a synonym (Warén, 1984; Maxwell, 1992). Unless the available fossil material is well-preserved, in practice it is often difficult to distinguish Melanella from pyramidellid groups such as Odostomia Fleming, 1817, which has a variably strong plait on the adapical part of the columella. The Antarctic material, which is nicely preserved, belongs in Melanella. Melanella seymourensis, new species Plate 7, figures 1—4 Diagnosis.—High-spired Melanella with more than five gently inflated, subtrapeziform whorls with only slightly impressed sutures; whorls polished, smooth, with only closely spaced microscopic spiral threads, opisthocyrt growth lines and a few groove-like varices; aperture tear-shaped; easily distinguished from M™. pontilis Maxwell, 1992, in having opisthocyrt growth lines and more swollen whorls that have more im- pressed sutures. Description.—Species small- to medium-sized for genus, thin-shelled, high-spired, subulate, polished, imperforate; spire high, subgradate, of at least five sub- trapeziform, gently swollen whorls; spire angle acute; sutures only slightly impressed; whorl inflation grad- ual; protoconch unknown, broken on available mate- rial; last whorl weakly inflated and convex, mostly smooth apart from many, closely spaced microscopic spiral threads and closely spaced, sinuous opisthocyrt growth lines; teleoconch whorls similarly sculptured; aperture moderately small, tear-shaped, holostomatous; pillar smooth, straight to only slightly concave, with very narrow, slightly raised callus; outer lip thin, smooth. Dimensions.—Holotype USNM 511868, height 5.5 mm, diameter of last whorl 2.0 mm; paratype USNM 511869, height 6.25 mm, diameter of last whorl 2.5 mm; paratype USNM 511870, height 4.0 mm incom- plete. Types.—Holotype USNM 511868; paratypes, USNM 511869, USNM 511870. Localities.—1519, 1535 (type). EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. Bi Material.—Two mostly complete specimens and several fragments. Stratigraphic range.—1072 to 1078 m. Discussion.—The oldest records of Melanella are in the Southern Hemisphere and are represented by M. seymourensis n. sp. from the Sobral Formation, M. lautoides Finlay and Marwick, 1937, from the late ear- ly Paleocene of the Wangaloa Formation of New Zea- land, and Melanella? n. sp. of Stilwell (1994) from the mid-Paleocene Kauru Formation, also of New Zea- land. The Kauru Formation species (Stilwell, 1994, pp. 937-938, pl. 68, fig. 6) is most like M. seymourensis in having a subulate, high-spired, polished shell, but the growth lines of M. seymourensis are opisthocyrt, whereas those of Melanella? n. sp. are more opisth- ocline. The Kauru Formation species was tentatively placed in Melanella as the aperture in the only known specimen is incomplete. All preserved features of this shell point to an allocation to Melanella. M. lautoides Finlay and Marwick, 1937 (p. 66, pl. 5, fig. 11; Flem- ing, 1966, p. 388, pl. 145, fig. 1748; Stilwell, 1994, pp. 935-937, pl. 68, figs. 1-5) has a much lower spired shell with a more gradate spire and deeper, more or- thocline growth lines, and more channeled sutures. Melanella pontilis Maxwell, 1992 (p. 120, pl. 16, figs. e, f) from the late Eocene of New Zealand is strikingly like M. seymourensis, but M. pontilis has a taller spire, more flush whorls and less distinctive opisthocline growth lines, compared to the Antarctic species. Of note, Melanella sp. of Finlay and Marwick (1937, p. 66, pl. 5, figs. 18, 19; Fleming, 1966, p. 388, figs. 1749, 1750) from the mid-Paleocene of Boulder Hill, South Island, New Zealand, doubtfully belongs to Melanella and may represent a species of Odosto- mia because of the preserved plait situated high on the pillar adapically. Etymology.—Species named for its endemic occur- rence on Seymour Island. Superfamily MURICOIDEA Rafinesque, 1815 Family TUDICLIDAE Cossmann, 1901, emend. Finlay and Marwick, 1937 Genus HETEROTERMA Gabb, 1869 Type species (by monotypy).—Heteroterma tro- choidea Gabb, 1869. Heteroterma?, new species Plate 7, figures 13, 14 Description.—Shell small- to medium-sized (up to 18.5 mm), moderately thick-shelled, low-spired bicon- ic; spire moderately low, of at least 3 weakly convex, noded whorls; protoconch paucispiral, smooth, only partially preserved on available specimen; spire angle approximately 77°; whorl inflation rapid from penul- timate to last whorl; suture slightly impressed, last whorl nearly clasping around noded penultimate whorl; sutural ramp steep; last whorl uniangulate, in- flated, with noded central keel; ornamentation of 12 well-developed tubercles centrally on keel and more than 25 spiral cords that are more bunched on base: growth lines weak, opisthocyrt; tubercled keel on pen- ultimate whorl located just adapical of suture; base contracting to short neck; aperture broad, ovate; col- umella obscured by matrix; outer lip slightly thickened at keel. Dimensions.—USNM 511871, height 18.5 mm, di- ameter of last whorl 14.5 mm. Locality.—1104. Material.—One specimen. Stratigraphic occurrence.—1375 m. Discussion.—The biconic outline and sculpture of strong tubercles and spiral cords of this probable tud- iclid approaches Heteroterma trochoidea Gabb, 1869 (p. 152, pl. 26, figs. 30, 30a; see review by Saul, 1988a, pp. 13-14, figs. 12, 72-76) and H.? acrita Saul, 1988a (pp. 14—16, figs. 13, 77-84) from the late Pa- leocene of California, but the shell of Heteroterma? n. sp. 1s somewhat abraded with loss of part of the si- phonal canal and sculpture details. It is not known whether or not a fasciole is present in this new Ant- arctic species. The suture of Heteroterma? n. sp. is somewhat clasping with the nodose keel of the pen- ultimate whorl just visible, as in H. trochoidea, where- as in H.? acrita the last whorl envelops the nodose keel of the penultimate whorl and takes the form of a steep collar or subsutural welt. More specimens are needed to confirm a genus-level assignment. Genus PYROPSIS Conrad, 1860 Type species (by monotypy).—Tudicla (Pyropsis) perlata Conrad, 1860. Discussion.—Although beyond the scope of this pa- per, further research on the problematic “*Wangaloan” Paleocene New Zealand species Heteroterma zelan- dica Marshall, 1917, and related Cretaceous and Pa- leocene taxa such as Cominella? praecursor Wilckens, 1905 (= Struthilariopsis? tumida Wilckens, 1905), Heteroterma elegans Griffin and Hiinicken, 1994, Pyr- opsis? gabbi (Stanton, 1896) [Heteroterma] and Het- eroterma? acrita Saul, 1988a, is necessary to clarify relationships of these closely related groups (Stilwell, 1993, 1994). Heteroterma zelandica is not a Hetero- terma as it is very much distinct from the type species, H. trochoidea Gabb, 1869, which has a developed fas- ciole, narrower and less expanded lip, moderately short siphonal canal, and a suture that does not cover the adapical series of nodes, very much distinct from H. 38 BULLETIN 367 zelandica. The new Antarctic species, Pyropsis? aus- tralis n. sp. described below, is very closely related to H. zelandica and both are congeneric and probably derived from the same stock. A full review of these taxa is being prepared by one of us (JDS), and until this work is completed in conjunction with the well- preserved New Zealand material, the Austral forms will be retained in closely allied Pyropsis. Pyropsis? australis, new species Plate 7, figures 9, 10 Diagnosis.—Moderately sized, robust, low-spired Pyropsis? with apical angle of 82°; 12-13 axially ex- tending tubercles and some 25 wavy spirals; steep sub- sutural ramp that wraps around tubercles of penulti- mate whorl yielding a band that has a wavy appear- ance, penultimate whorl with slightly swollen subsu- tural band giving a_ gently concave profile; distinguished from closely allied New Zealand species, “P. zelandica (Marshall, 1917), in having a higher spire, steeper adapical slope, less developed sutural band and fewer axials and spirals. Description.—Shell medium-sized for family (up to 47.5 mm high), relatively robust, thick, pyriform; spire low, conical, consisting of at least 4 compressed, gent- ly convex whorls; protoconch small, paucispiral, con- ical, a bit eroded on holotype; spire angle 82°; whorl inflation very rapid from penultimate to last whorl; suture complex with ill-defined, relatively blunt, axi- ally extending tubercles, bounded adapically by nar- row, wavy zone on extreme abapical part of last whorl that essentially wraps around adapical nodulation of penultimate whorl like a wavy band, on swollen, most- ly spirally sculptured, obliquely truncated, abapical an- gulation; last whorl capacious with short, rather steep adapical ramp that is gently concave, merging with distinctly angled periphery of ~12—13 moderately strong, broad, axially extending tubercles and spiral ornamentation of more than 25 wavy spiral cords that are more spaced on angulation; penultimate whorl with 6 narrow spiral cords; growth lines on last whorl op- isthocyrt on ramp becoming orthocline and just slight- ly sinuous on angulation and canal; basal constriction rapid; growth lines on teleoconch whorls opisthocyrt; aperture well open, broadly lenticular, with mostly straight columella; callus moderately thick, spreading into parietal glaze; siphonal canal moderately long, narrow, tapered; outer lip thickened. Dimensions.—Holotype USNM 511872, height 47.5 mm, diameter of last whorl 30.0 mm. Type.—Holotype USNM 511872. Locality.—1104. Material.—One specimen. 375s. Stratigraphic occurrence. Discussion.—Pyropsis? australis n. sp. is congener- ic with, and most closely allied to, Heteroterma zelan- dica Marshall, 1917 (pp. 453—454, pl. 35, figs. 20, 21; Finlay and Marwick, 1937, pp. 84—85, pl. 10, figs. 8— 10; Fleming, 1966, p. 322, pl. 112, figs. 1367-1369; Beu and Maxwell, 1990, pp. 84-86, pl. 2, fig. p; Stil- well, 1994, pp. 986-997, pl. 70, figs. 5, 9, 13-18) (= n. gen. aff. Pyropsis), one of the most characteristic and commonly figured Paleocene gastropods of New Zealand. These two taxa are strikingly similar, and dif- fer mainly in height of spire and minor sculptural at- tributes. Pyropsis? australis is distinguished from P.? zelandica in having a slightly higher spire, a slightly steeper adapical ramp on the last whorl, a less devel- oped sutural band, fewer axially extending tubercles, and fewer spiral cords. The Antarctic species is prob- ably slightly older than the New Zealand species, which is considered to be late early Paleocene in age (Stilwell, 1994). Heteroterma elegans Griffin and Hiinicken, 1994 (pp. 267-269, figs. 7.1, 7.2) from the Paleocene of Patagonia is also a congeneric form that has a longer siphonal canal, poorly developed tuber- cles, a less swollen subsutural band, compared to P.? australis and P.? zelandica. Of note, the only species comparable to P.? australis in the Northern Hemi- sphere are H.? acrita Saul, 1988a (pp. 14—16, figs. 13, 77-84) (= Pyropsis?) and H. striata Stanton, 1896 (p. 1046, pl. 67, fig. 5; Dickerson, p. 151, pl. 17, fig. 1; Zinsmeister, 1983, p. 1299, figs. 30, P; Saul, 1988b, pp. 885-886, figs. 2.3, 3.26—3.30) (= Pyropsis’?), from the Paleocene of California, but these taxa have small- er shells, slightly more developed tubercles, and a more swollen subsutural band, compared to P.? aus- tralis. The distribution of these species of Pyropsis? suggests that the group was well established in Danian shallow waters extending from western North America to the southern rim of the southern circum-Pacific. Etymology.—Species named for its Austral occur- rence. Superfamily BUCCINOIDEA Rafinesque, 1815 Family BUCCINIDAE Rafinesque, 1815 Subfamily BUCCININAE Rafinesque, 1815 Genus COLUS Rdéding, 1798 Type species (by original designation).—Colus is- landicus (Gmelin, 1791). Colus delrioae, new species Plate 7, figures 15—20 Diagnosis.—Large smooth Colus with moderately high spire of at least 7 rather compressed and weakly convex to almost flush whorls; spire angle approxi- mately 36° to 38°; shell nearly void of sculpture apart EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 39 from widely spaced, very weak spirals, and equally weak growth lines; base well contracted; siphonal ca- nal moderately long, gently twisted abaxially; colu- mella smooth and concave; differs from Recent type species, C. islandicus (Gmelin, 1791) in having a high- er spire with less convex and more flattened, flush whorls and weaker spiral ornamentation. Description.—Shell large (up to 90 mm high), rath- er slender, moderately thick-shelled, high-spired fusi- form; spire moderately high to high of at least 7 com- pressed, very weakly rounded to nearly flush whorls that approach a near gradate outline; protoconch par- tially present, paucispiral, smooth; spire angle acute of between 36° to 38°; whorl inflation moderately slow on spire increasing rapidly from penultimate to last whorl; sutures very weakly impressed: last whorl in- flated, convex, smooth and polished apart from weak, but broad, spiral ribs that are widely spaced, and weak growth lines that are opisthocline medially becoming more prosocline near base; spire whorls void of sculp- ture apart from microscopic spiral threads and faint opisthocyrt growth lines; last whorl contracts abruptly at base, producing a moderately long, gently oblique and twisted canal that is narrowly channeled; colu- mella moderately long, smooth, concave with narrow callus; outer lip thin, smooth. Dimensions.—Holotype UBA 16816, height 90.0 mm, diameter of last whorl 44.0 mm; paratype USNM 511873, height 51.5 mm, diameter of last whorl 24.0 mm (immature individual); paratype USNM 511874, height 38.5 mm, diameter of last whorl 25.5 mm. Types.—Holotype UBA 16816; paratypes, USNM 511873, USNM 511874. Localities.—1431, 1535, 1556. Material.—Three specimens. Stratigraphic range.—1077 to 1144 m. Discussion.—This enigmatic high-spired gastropod is rare in the Sobral Formation and is represented by three specimens, of which only one is moderately well preserved (an immature individual, USNM 511873). No other related species are recorded from the Ant- arctic fossil record or from the Recent. The outline and weak spiral sculpture is consistent with the Tertiary to Recent genus Colus Réding, 1798, type species C. is- landicus (Gmelin, 1791) (see Abbott and Dance, 1983, p. 163, colored figure), from Labrador to Norway. The siphonal canal is longer in C. islandicus and the whorls are more convex, but the Seymour Island species fits comfortably in the group, acknowledging the variable nature of this buccinid. Few fossil members of Colus approach the Antarctic species, but Fasciolaria rhom- boidea Rogers, 1839 (p. 376, pl. 30, fig. 3) (= Colus?) from the mid-Tertiary of Virginia is similar. Colus? rhomboidea has more rounded, convex whorls, com- pared with C. delrioae n. sp. The evolutionary history of Colus delrioae is un- certain and the group apparently did not survive after the Paleocene in Antarctica. This species is in all like- lihood a migrant species, but the imperfect preserva- tion of the available material prevents an in-depth in- vestigation of this unusual new group. Etymology.—This species is named for Dr. Claudia del Rio, University of Buenos Aires, who found the magnificent holotype of this species. Genus PSEUDOFAX Finlay and Marwick, 1937 Type species (by original designation).—Phos or- dinarius Marshall, 1917. Discussion.—Pseudofax was one of the most wide- spread buccinid gastropods in lower Tertiary shallow- marine deposits in the Southern Hemisphere. This group is represented in the early late Paleocene to mid- dle Eocene of New Zealand, Paleocene of southern Patagonia, mid-Paleocene of southeastern Australia, and from this work from earliest Paleocene to middle Eocene of Antarctica (see Finlay and Marwick, 1937; Stilwell and Zinsmeister, 1992; Stilwell, 1994; Griffin and Hiinicken, 1994; Darragh, 1997; Stilwell, 2000). Pseudofax, a generalized buccinid, was recently re- viewed in detail by Beu and Maxwell (1990, p. 83) and Stilwell and Zinsmeister (1992, pp. 124—125), so only a brief summary is appropriate here, with addi- tional records of this representative of a post K-T boundary “bloom taxon.” Pseudofax, as the name suggests, has an affinity with Fax Iredale, 1925, but protoconch differences separate the two groups: Pseu- dofax has a broadly conical protoconch, different from the cylindrical protoconch in Fax. Pseudofax is con- sidered to be intermediate morphologically among Nassicola, Zelandiella, Eucominia, Cominula, and Procominula, all Finlay (1926) buccinid genera. Wenz (1941, p. 1176) believed Pseudofax to be a subgenus of Phos Montfort, 1810, type species P. senticosus (Linnaeus, 1758) (see Wenz, 1941, p. 1175, fig. 3338), but the distinctive highly ornamental shell and aperture of P. senticosus effectively separates these groups at genus level. Pseudofax? paucus, new species Plate 8, figures 25, 26 Diagnosis.—Average-sized Pseudofax, but small for Buccinidae, relatively thin-shelled, moderately high- spired fusiform to elongate-ovate in outline; more than 3 convex spire whorls; spire angle about 59°; orna- mentation of some 15 equally spaced spiral cords and about 10 poorly developed, rounded axials; inner part of outer lip lirate; distinguished from type species, P. 40 BULLETIN 367 ordinarius (Marshall, 1917), in having generally more inflated whorls, less wavy spiral cords, reflecting a more subdued axial component, and broader more ovate aperture. Description.—Shell small for family (height 14 mm), broadly fusiform to elongate-ovate; spire mod- erately high of more than 3 rather squat, convex whorls; whorl inflation relatively rapid; spire angle ap- proximately 59°; protoconch details unknown; sutures impressed; last whorl moderately inflated, convex, or- namented with 15 equally spaced spiral cords and in- cised interspaces, and about 10 rounded, poorly de- fined, axial ridges; growth lines weak, poorly defined, orthocline to barely opisthocyrt; spire whorls with 5— 6 spiral cords and no perceptible axials; base contract- ed abruptly to short, notched, oblique, siphonal canal; columella short, concave with thin, narrow callus; fas- ciole poorly developed; aperture broad, ovate; inner part of outer lip lirate; outer lip relatively thin. Dimensions.—Holotype USNM 511875, height 14.0 mm, diameter of last whorl 9.5 mm. Type.—Holotype USNM 511875. Type locality.—1589. Material.—Holotype. Stratigraphic range.—1149 m. Discussion.—This rare species compares well with the Paleogene buccinid Pseudofax, type species P. or- dinarius (Marshall, 1917) (p. 456, pl. 35, figs. 24, 25: Wenz, 1941, p. 1176, fig. 3341; Finlay and Marwick, 1937, p. 80, pl. 9, figs. 16, 18; Beu and Maxwell, 1990, p. 83, pl. 2, fig. t), but the shell outline of the new Antarctic species is relatively broader, the spiral cords are more uniform and less wavy, and the aper- ture is more open and ovate. Phos conica Marshall, 1917, was relegated to subspecies-level status by Fin- lay and Marwick, (1937, p. 80), who believed it to be a subspecies of Pseudofax ordinarius. Beu and Max- well (1990) recognized the variability of P. ordinarius and considered P. conicus to be a morphotype, albeit extreme, of P. ordinarius. Stilwell (1994) supported Beu and Maxwell’s conclusions by collecting a large number of these morphotypes. Other Paleocene Aus- tral taxa, such as P. costellatus Griffin and Hiinicken, 1994, from southwestern Patagonia, and P. cf. P. or- dinarius from southeastern Australia, are not closely related. Although the preservation of the holotype is not overly well-preserved, there is evidence to suggest that P. paucus? n. sp. is the ancestor to P. weddellensis Stlwell and Zinsmeister, 1992, and P. suroinflatus Stilwell and Zinsmeister, 1992, from the La Meseta Formation. Pseudofax? paucus has narrower spiral cords and a much weaker axial component, compared with the Eocene Antarctic species. Pseudofax weddel- lensis (see Stilwell and Zinsmeister, 1992, pl. 16, figs. x-z) is morphologically very close to P.? paucus and probably represents a lineage. Etymology.—Species named from the Latin paucus (equivalent to “few, little’) for its rare occurrence on Seymour Island. Subfamily MELONGENIINAE Gill, 1867 Genus LEVIFUSUS Conrad, 1865 Type species (by original designation).—Fusus tra- beatus Conrad, 1833. Discussion.—Levifusus is recorded from Antarctica for the first time, previously cited from Paleocene to Eocene rocks of southeastern United States (Toulmin, 1977), East and West Africa (Adegoke, 1977; Gliozzi and Malatesta, 1985), and probably Australia (Dar- ragh, 1997). Southern Hemisphere records of the group are rare, compared to the much higher diversity in North America. Levifusus woolfei, new species Plate 9, figures 23-29 Diagnosis.—Relatively large Levifusus, with mod- erately high-spired, robust shell; whorls well shoul- dered with greatly inflated last whorl bearing 3 keels, the adapical one strongest with 11—12 spirally extend- ing tubercles; spire angle 120°; rows of tubercles not all aligned; penultimate whorl with strong angulation, bearing 14 small nodes; siphonal canal short, twisted abaxially; outer lip relatively thin without tubercles; distinguished from type species, L. trabeatus (Conrad, 1833), in having a more inflated last whorl, lower spire, more projecting tubercles, and short canal. Description.—Shell large (up to 57 mm high), ro- bust, moderately high-spired for genus, pyriform, with modestly elevated spire of at least 3 nodulose, well- shouldered whorls; somewhat enveloped from suc- ceeding whorls; spire angle obtuse, approximately 120°; whorl inflation very rapid from penultimate to last whorl; protoconch minute, paucispiral, dome- like?; sutures clasping around succeeding whorls and wavy; last whorl capacious, very inflated, tricarinate, highly ornamented with rows of nodes that are not all aligned; adapical ramp of last whorl moderately steep, short, mostly straight to only marginally concave, merging with a strong adapical peripheral angulation of 11-12 variable, spirally extending, inflated tuber- cles, central angulation spaced ~5 mm from adapical angulation, ornamented with ~12 slightly weaker, spaced tubercles; lowermost abapical keel rather weak, close to medial one, spaced about 3—4 mm, orna- mented with weak, only slightly raised tubercles; pen- ultimate whorl with strong medial angulation, bearing ~14 projecting, closely spaced nodes with moderately steep adapical ramp and very steep, nearly vertical EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 4] slope below angulation, meeting suture of last whorl; only weak angulation and poorly developed nodes on antepenultimate whorl; growth lines very weak, mostly prosocline; last whorl abruptly contracted by strong basal constriction to short, twisted canal; aperture large, broadly ovate to sublenticular; columella long, smooth, concave with broad callus pad, that spreads in parietal region over medial and abapical rows of tu- bercles; siphonal canal moderately broad, twisted slightly abaxially; outer lip relatively thin, void of tu- bercles in adult specimens. Dimensions.—Holotype USNM 511876, height 57.0 mm, diameter of last whorl 43.5 mm; paratype USNM 511877, height 44.0 mm, diameter of last whorl 40.5 mm; paratype USNM 511878, height 51.5 mm, di- ameter of last whorl 43.0 mm. Types.—Holotype USNM _ 511876; paratypes USNM 511877, USNM 511878. Localities.—9 (type), 479, 496, 1434, 1435, 1505, 1538, 1587. Material.—39 specimens. Stratigraphic range.—1168 to 1179 m. Discussion.—Levifusus woolfei n. sp. is most close- ly related to L.? quadrifunifer Darragh, 1997 (pp. 76— 77, fig. 3S, U) from the Paleocene of Australia, the only other member of the group in the Southern Hemi- sphere. No post-Paleocene records of the genus are known in the Austral Realm. Levifusus woolfei has a tricarinate profile like L.? quadrifunifer, but it is not as well-developed as in the Australian species. The spire in L. woolfei is also higher, compared with L.? quadrifunifer, which further has less projecting tuber- cles. The type species, L. trabeatus (Conrad, 1833) (p. 53, pl. 18, fig. 1 (see Harris, 1893, for discussion of the pagination of this complicated and rare original work); Wenz, 1943, p. 1222, fig. 3473), has a more gracile, high-spired shell, a longer siphonal canal, and a less inflated last whorl, but the relationship of the Antarctic species to the type is secure. In our opinion, L. mortonii (1. Lea, 1833) (p. 145, pl. 5, fig. 145: see also Toulmin, 1977, pp. 289-290, pl. 48, fig. 8), and L. mortoniopsis (Gabb, 1860) (p. 377, pl. 67, fig. 15: see also Toulmin, 1977, p. 290, pl. 48, fig. 6) from the eastern Gulf Coast are probably not congeneric, as there is an axial component and strong spiral element along with a straight canal, not present in the type. Levifusus maputi Gliozzi and Malatesta, 1983 (pp. 105—106, pl. 7, figs. 3-5), from the Paleocene of Moz- ambique is also not a close relative of L. woolfei, as the Mozambique species has a very marked shoulder angulation and higher spire, unlike L. woolfei. The Af- rican species described in Adegoke (1977) (see pp. 180-182, pl. 28, figs. 16-19) may not belong in Lev- ifusus either, as both the axial and spiral ornament is marked. Etymology.—Species named in honor of our late young colleague, Ken Woolfe, James Cook University, who passed on tragically in December 1999, for his ceaseless enthusiasm and voluminous contributions to Antarctic geology. Genus PROBUCCINUM Thiele, 1912 Type species (by original designation).—Neobuccin- um tenerum Smith, 1907. Probuccinum palaiocostatum, new species Plate 10, figures 1—3 Diagnosis.—Teleoconch of 5 convex whorls, axial sculpture of broad folds, spiral ornamentation of thin threads, siphonal canal slightly curved, fasciole weak to inconspicuous. Description.—Shell of small size (up to 50.2 mm high), thin to moderately thick in larger specimens, with up to 5 convex rounded whorls, separated by ad- pressed suture; protoconch not preserved: aperture semi-ovate, moderately wide; axial sculpture of straight to slightly curved folds, becoming wider and lower, to completely obsolete, in some specimens on the last whorl; spacing between folds is approximately equal to the width of the folds; examined specimens with 15—17 folds on last and penultimate whorls; spiral sculpture fine, slightly raised threads separated by in- terspaces of equal width; aperture subovate, tapering anteriorly and posteriorly; siphonal canal slightly curved, fasciole weak, inconspicuous on most speci- mens; outer lip thin, simple; inner lip smooth, gently concave; siphonal canal slightly curved sinistrally. Dimensions.—Holotype USNM 511879, height 26.0 mm, diameter of last whorl 21.0 mm; paratype USNM 511880, height 54.0 mm, diameter of last whorl 31.0 mm; paratype USNM 511881, height 44.0 mm incom- plete, diameter of last whorl 28.0 mm. Types.—Holotype USNM 511879; paratypes 511880, USNM 511881. Localities.—9, 746 1434, 1699, 1701. Material.—Eight specimens. Stratigraphic range.—1134 to 1167 m. Discussion.—The holotype of Probuccinum palaio- costatum n. sp. is apparently an immature individual without distinct axial sculpture developed on the last whorl. It differs from the Recent circum-Antarctic spe- cies P. costatum Thiele, 1912 (p. 211, pl. 13, fig. 22; see Dell, 1990, p. 171, fig. 285), in having a lower spire, a more rounded and convex whorl profile, and wider axial folds, separated by interspaces of equal width. Probuccinum palaiocostatum is the oldest member of this endemic Antarctic group. 42 BULLETIN 367 Etymology.—Species named from the Latin palaios (equivalent to “ancient, old”) and Latin costa (equiv- alent to “‘rib’’). Genus SERRIFUSUS Meek, 1876 Type species (by monotypy).—Fusus dakotensis Meek and Hayden, 1856. Discussion.—Serrifusus 1s a rare gastropod, known previously from North America by two species, the type S. dakotensis (Meek and Hayden, 1856), from the latest Campanian-Maastrichtian of Wyoming (perhaps also known from Hormby Island, Vancouver Island area, Canada; see Whiteaves, 1879, and Sohl, 1967, p. B29), and S. joaquinensis Anderson, 1958, from the Campanian of California. The Antarctic record from the Sobral Formation is the only one outside North America and also the only record from the Tertiary. Serrifusus binodosum, new species Plate 9, figures 1-5, 8-10 Diagnosis.—Moderately sized Serrifusus with at least 4 shouldered whorls with steep adapical slopes: last whorl bicarinate with moderately developed close- ly spaced noded keels, small, sharp nodes nearly aligned with weakly opisthocyrt, sinuous growth lines; outer lip slightly thickened, sinuous, with moderately developed flare below lower keel; canal short, slightly twisted; distinguished from type, S$. dakotensis (Meek and Hayden, 1856), in having a smaller shell, closer more sharply noded keels, and a shorter canal. Description.—Shell medium-sized, short-spired fu- siform, moderately thick; spire of at least 4 shouldered, compressed whorls with moderately steep slopes; pro- toconch medium-sized, dome-like, of at least one smooth whorl, slightly eroded in available material; whorl inflation very rapid from penultimate to last whorl; spire angle approximately 62°; sutures chan- neled, encroaching on penultimate whorl at outer lip; last whorl moderately inflated, bicarinate, keels closely spaced and slightly concave between, bearing 20—21 only slightly axially extending, small, sharp tubercles, that are nearly parallel and connected by slightly ex- cavated raised rib, and follow the moderately weak opisthocyrt growth lines; adapical ramp of last whorl long, steep, contracting greatly to a short canal except for contour of outer lip which hardly contracts, and is slightly flared and convex; spiral sculpture weak of equally and closely spaced threads only apart from noded keels; additional weakly noded spirals variably present on last whorl, but subsidiary to noded keels; spire whorls of weak spiral lines and two weakly nod- ed spiral ribs, located just adapical of suture; aperture large, ovate, some 70% of height of shell, contracting to short, slightly obliquely twisted, narrow canal; col- umella concave with moderately developed callus pad; outer lip sinuous, moderately thick and varix-like on adult holotype, and flared abapically just below low- ermost row of tubercles producing a curved concavity. Dimensions.—Holotype USNM 511882, height 41.0 mm, diameter of last whorl 26.5 mm; paratype USNM 511883, height 35.0 mm, diameter of last whorl 23.5 mm; paratype USNM 511884, height 38.0 mm, di- ameter of last whorl 24.0 mm (specimen showing se- vere repaired break); paratype USNM 511885, height 33.5 mm, diameter of last whorl 25.0 mm, most of canal missing; paratype USNM 511886, height 32.0 mm, diameter of last whorl 21.0 mm, immature indi- vidual. Types.—Holotype USNM 511882; paratypes USNM 511883, USNM 511884, USNM 511885 USNM 511886. Localities.—497, 746, 1104, 1138, 1431. Material.—39 specimens. 1134 to 1375 m. Discussion.—Serrifusus binodosum n. sp., a K-T boundary survivor, is the only Tertiary representative of this genus in the fossil record and can be separated from the latest Cretaceous North American type spe- cies, S. dakotensis (Meek and Hayden, 1856) (p. 65; Meek, 1876, p. 374, pl. 31, fig. 11, pl. 32, figs. a, c, also same paper S. goniophorus Meek, p. 375, pl. 32, fig. 7a, b?; Wenz, 1941, p. 1262, fig. 3594; Sohl, 1967, p. B29-B30, pl. 6, figs. 12, 13, 18-21), in having a smaller shell, more closely spaced noded keels, sharper nodes, and a more expanded sinuous outer lip. Serri- Stratigraphic range. fusus joaquinensis Anderson, 1958 (pp. 171-172, pl. 49, fig. 3) from the latest Cretaceous of the Pacific Coast is not closely allied with S. binodosum, as it has a much higher, more strongly unicarinate spire and last whorl. We believe that the Antarctic species falls into the limit of variability of this genus. Intraspecific var- iation 1s apparent in §. binodosum with various strengths of noded keels present in the type material. On the holotype, USNM 511882, a third adapical spi- ral row of nodes disappears gradually on the last whorl midway on the volution. Another specimen, paratype USNM 511884, has a severe repaired break, affecting the sculpture of the last whorl, making it quite irreg- ular. This break was probably made by a “‘lip-peeler”’ such as a decapod crustacean. Etymology.—Species named from the Latin nodosus (equivalent to “‘full of knots”) for its distinctive two spiral rows of nodes or tubercles. Genus SYCOSTOMA L. R. Cox 1931 Type species (by original designation).—Fusus bul- biforme Lamarck, 1803. Discussion.—Sycostoma has been recorded in Up- EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 43 per Cretaceous to Paleogene rocks of Europe, Mada- gascar and North America (Wenz, 1943, p. 1222), up- permost Cretaceous rocks of New Zealand (Fleming in Wellman, 1959; Stilwell, 1994), and Paleocene of Greenland (Kollmann and Peel, 1983). Austroficopsis Stilwell and Zinsmeister, 1992, may be a closely re- lated form. Melongenine gastropods are rare in Austral Cretaceous and Paleogene deposits. Sycostoma is re- ported herein from Antarctica for the first time. Sycostoma pyrinota, new species Plate 8, figures 23, 24 Diagnosis.—Small to moderately sized Sycostoma with low spire with at least two weakly convex whorls: spire angle about 74°; length of last whorl about 80% total height of shell; sculpture of rather weak, closely spaced, spiral threads, ~3 per mm; siphonal canal moderately long and broadly notched; most closely re- lated to latest Cretaceous New Zealand species, S. n. sp. of Stilwell (1994), differing by the new Antarctic species being half the size with weaker spirals and longer canal. Description.—Shell small- to medium-sized for ge- nus (27 mm high), low-spired, moderately robust, pyr- iform; spire obtuse, low, paucispiral, of at least two weakly convex, steeply sided whorls; whorl inflation rapid, especially from penultimate to last whorl; pro- toconch unknown; spire angle approximately 74°; su- tures weakly impressed; last whorl length about 80% of total height of shell; last whorl moderately inflated, ovately elongated, moderately convex, sutural ramp steep, ornamented with equally and closely spaced, weak spiral cords, ~3 per mm, equally strong from canal to suture; penultimate whorl similarly sculp- tured; growth lines very weak, nearly opisthocline; base contracted to a moderately long neck; siphonal canal moderately broad, notched; columella smooth, convex, long; outer lip thin. Dimensions.—Holotype USNM 511887, height, 27.5 mm, diameter of last whorl 17.0 mm. Type.—Holotype USNM 511887. Locality.—9. Material.—One specimen. Stratigraphic occurrence.—1168 m. Discussion.—Sycostoma pyrinota n. sp. is the only member of this genus in Antarctica and is closely re- lated to a slightly older Maastrichtian form, Sycostoma n. sp., from Northland, New Zealand (see Stilwell, 1994, pp. 673-676, pl. 43, figs. 1-4). Sycostoma pyr- inota may be the descendant of Sycostoma n. sp. from New Zealand, as the outline and sculpture is nearly identical, except that the Antarctic species is half the size with a slightly shorter, broader canal. No other member of this group has been recorded from the Southern Hemisphere, so the genus may have evolved in the north, where there is a much better and diverse record. The European Eocene type species, S. bulbi- forme (Lamarck, 1803) (p. 287; see Swainson, 1840, p. 308, fig. 75; Cossmann, 1889, p. 168; Wenz, 1943, p. 1222, fig. 3475; Oleinik and Zinsmeister, 1996, p. 927, fig. 4), is also larger than S. pyrinota with a high- er spire, slightly more inflated whorls, and a more de- veloped labial callus. Sycostoma jonesi Adegoke, 1977 (pp. 146-147, pl. 23, figs. 1-6) from the Paleocene of Nigeria is not a closely related species and has much more compressed spire whorls and is more globose, compared with S. pyrinota. Sycostoma disappeared from the fossil record in Antarctica after the early Pa- leocene. Etymology.—Species named for its pyriform outline and from the Greek notos (equivalent to “‘south’’) for its sole presence in Antarctica. Subfamily PPEUDOLIVINAE? Cossmann, 1901 Genus SEYMOUROSPHAERA Oleinik and Zinsmeister, 1996 Type species (by original designation).—Seymou- rosphaera bulloides Oleinik and Zinsmeister, 1996. Discussion.—Seymourosphaera is seemingly allied with Austrosphaera Camacho, 1949, and is distin- guished from the Argentine group in having “‘[a] more concave columella, generally broader and thicker cal- lus, narrower and shallower parietal and siphonal ca- nals, lacking a fasciole, and prominent spiral sculp- ture” (Oleinik and Zinsmeister, 1996, p. 926). This characteristic endemic group is associated with the re- population phase in Antarctica immediately following the K-T boundary (WJZ and JDS). Seymourosphaera shares features in common with both Buccinidae and Nassariidae, so it is tentatively placed in Buccinidae Pseudolivinae. Four species have been recognized in the Paleocene sequence of Seymour Island. Details are provided below. See Oleinik and Zinsmeister (1996) for detailed discussion of distinguishing features of these species, and their relationships to other closely related forms, not repeated herein. Seymourosphaera bulloides Oleinik and Zinsmeister, 1996 Plate 8, figures 1—7 Seymourosphaera bulloides Oleinik and Zinsmeister, 1996, pp. 926, 929-930, figs. 2.1, 2.3, 5.1-5.6, 5.10-5.11, 5.20, 5.21. Dimensions.—Holotype USNM 487298, height 41.3 mm, diameter of last whorl 27.3 mm (see Table 1, Oleinik and Zinsmeister, 1996, p. 930) for dimensions of paratypes. Types.—Holotype USNM 487298; paratypes 44 BULLETIN 367 USNM 487294, USNM 487296, USNM 487289, USNM 487300, PU 496, PU 746, PU 995, PU 1135, PU 1430, PU 1432. Localities.—9, 119, 496, 746, 1134, 1135, 1136, 1430, 1431, 1432 (type), 1434, 1506. 1538, 1589, 1601, 1694, 1700. Material.—98 specimens. Stratigraphic distribution.—1058 to 1168 m. Discussion.—Seymourosphaera bulloides is easily separated from Austrosphaera glabra Comacho, 1949, by having a more elevated and wider callus, generally elongated shape, lack of fasciole and presence of well- developed spiral sculpture on the upper part of the body whorl. Austrosphaera patagonica (Ferugho, 1936) has a narrower callus, and a much wider aper- ture, well-developed fasciole and siphonal notch. Sey- mourosphaera subglobosa Oleinik and Zinsmeister, 1996, has a less elongated shell, lower spire, and wider apical angle. Seymourosphaera elevata Oleinik and Zinsmeister, 1996, has a more elongated shell, elevated spire, smaller apical angle and four rather than five whorls. Seymourosphaera depressa Oleinik and Zins- meister, 1996, has a lower spire, broader aperture and lacks radial sculpture on the spire whorls. Seymourosphaera subglobosa Oleinik and Zinsmeister, 1996 Plate 8, figures 10—13, 20 Seymourosphaera subglobosa Oleinik and Zinsmeister, 1996, p. 930, figs. 2.2, 5.9, 5.12-5.17. Dimensions.—Holotype USNM 487292, height 33.3 mm, diameter of last whorl 26.3 mm. Types.—Holotype USNM 487292; paratypes USNM 487293, USNM 487295, USNM 487297, PU 9, PU 496, PU! 1135, PU! 1430 Localities.—1133, 1136 (type), 1430. Material.—15 specimens. Stratigraphic range.—1145 to 1165 m. Discussion.—Austrosphaera glabra Camacho, 1949, differs from Seymourosphaera subglobosa in lacking distinct spiral sculpture, narrower callus, broader aperture, straight columella, and by the pres- ence of a fasciole. Seymourosphaera depressa has a less elevated spire, broader apical angle. Austros- phaera patagonia (Feruglio, 1936) has a fasciole, si- phonal notch, and a narrower callus and a generally more elongated shell. Seymourosphaera depressa Oleinik and Zinsmeister, 1996 Plate 8, figures 8, 9 Seymourosphaera depressa Oleinik and Zinsmeister, 1996, p. 930, figs. 5.7—-5.8. Dimensions.—Holotype USNM 487290, height 38.3 mm, diameter of last whorl 28.7 mm. Type.—Holotype USNM 487290; paratypes PU 9, PU 1135: Localities.—9, 1104, 1434 (type). Material.—Five specimens. Stratigraphic distribution.—1168 to 1375 m. Discussion.—Austrosphaera glabra Camacho, 1949, differs in having a generally narrow and thicker callus, absence of spiral sculpture on the spire whorls and by the presence of a fasciole. The shell of Sey- mourosphaera subglobosa is more inflated and the ap- erture is narrower with a more concave columella. Sey- mourosphaera bulloides.may be separated by is nar- rower aperture, higher spire, and more prominent spi- ral sculpture. Seymourosphaera elevata Oleinik and Zinsmeister, 1996 Plate 8, figures 14-19, 21, 22 Seymourosphaera elevata Oleinik and Zinsmeister, 1996, p. 931, figs..5-18,-5.19)5:22-5.27. Dimensions.—Holotype USNM 487288, height 37.4 mm, diameter of last whorl 26.0 mm. Type.—Holotype USNM 487288, paratypes, USNM 487287, USNM 487291, USNM 487299, PU 9, PU 496, PU 1430. Localities 496, 1119, 1135 (type), 1136, 1148, 1189, 1430, 1432, 1433, 1506, 1577, 1586. Material.—42 specimens. Stratigraphic range.—1071 to 1215 m. Discussion.—This is the most distinctive and easily recognizable species of Seymourosphaera on Seymour Island. It differs from the other species by the absence of regular spiral sculpture, smaller apical angle, and higher spire consisting of five whorls. Seymouros- phaera elevata differs from Austrosphaera glabra Ca- macho, 1949, in having a more elongated shape, high- er spire, and broader callus with a concave columella. Compared to A. patagonica (Feruglio, 1936), S. ele- vata has a more elongated shell, higher spire, concave columella and the absence of regular spiral sculpture, a well-developed fasciole and a siphonal notch. Genus STREPSIDURA Swainson, 1840 Type species (by original designation).—Murex tur- gidus (Solander, 1766). Strepsidura? polaris, new species Plate 8, figures 27, 28 Diagnosis.—Relatively small to moderately sized buccinid with moderately high, slightly concave to near papillate, spire and subfusiform outline; spire an- EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 45 gle about 54°; last whorl inflated with broadly cancel- late sculpture of rounded, broad axial costae and many incised spirals; base contracted to notched, oblique, spout-like canal; differs from type species, Strepsidura turgida (Solander, 1766), in having a higher, more con- cave spire, more robust ornamentation, and a shorter siphonal canal. Description.—Shell small- to medium-sized (23.5 mm high), moderately high-spired, moderately robust, subfusiform to somewhat inflated biconical outline: spire with slightly concave to near papillate outline, of at least 4, nearly stacked whorls; spire angle approxi- mately 54°; whorl inflation slow then rapid from pen- ultimate to last whorl; protoconch apparently large, in- complete on holotype; suture weakly impressed: last whorl moderately inflated, convex, ornamented with near opisthocline-trending, cancellate, broad, axial ribs and many incised, equally spaced, spiral ribs; spire whorl sculpture obscured by diagenetic alteration of shell; base contracted gradually to curved, abaxially twisted, spout-like, moderately broadly notched canal; columella moderately short, concave; smooth; outer lip smooth, thin. Dimensions.—Holotype USNM 511888, height 23.5 mm, diameter of last whorl 16.0 mm. Type.—Holotype USNM 511888. Locality.—9. Material.—One specimen. Stratigraphic occurrence.—1167 m. Discussion.—The only collected specimen of this species of buccinid gastropod has been slightly dia- genetically altered such that the ornamentation is not clearly preserved, especially on the spire. The subfus- iform outline and cancellate sculpture is consistent with members of the Pseudolivinae, and the Tertiary genus Strepsidura may be a likely candidate for genus- level assignment, as apart from the apparent lack of a plication on the columella, there is general agreement in shell outline, sculpture and the oblique-trending, notched siphonal canal. The Eocene European type species, S. turgida (Solander, 1766) (p. 26, pl. 4, fig. 51; see also Sowerby, 1821, pl. 291, fig. 7; Cossmann, 1889, pp. 162-163; Wenz, 1943, p. 1270, fig. 3611) has a lower spire, two columellar plaits, and a slightly longer siphonal canal. This species may represent a new group, but more material is needed to make a more concrete assessment. Other Paleocene species such as S. kerstingi Oppenheim, 1914 (p. 58, pl. 5, figs. 4a, b; Adegoke, 1977, pp. 158-159, pl. 24, figs. 22-26), from Nigeria and Strepsidura sp. of Kollmann and Peel (1983) (pp. 86-87, fig. 192) from Greenland are not closely related forms. Etymology.—Species named for its polar occur- rence. Family FASCIOLARTIIDAE Gray, 1853 Subfamily FASCIOLARIINAE Gray, 1853 Genus PALEOPSEPHAEA Wade, 1926 Type species (by original designation).—Paleopse- phaea mutabilis Wade, 1926. Paleosephaea? nodoprosta, new species Plate 9, figures 6, 7, 11-16 Paleopsephaea n. sp. Zinsmeister et al., 1989, p. 733, fig. 2, p. 734, fig: 3): Diagnosis.—Moderately sized Paleopsephaea with moderately low spire of more than 5 strongly noded whorls; spire whorls and last whorl bearing 12—14 pro- jecting tubercles, some more axially extending; si- phonal canal short, only gently twisted, with moder- ately broad notch; columella with at least two oblique plaits; distinguished from type species, P. mutabilis, in having peripheral projecting nodes most of which do not axially extend and a much shorter, notched canal. Description.—Shell medium-sized (up to ~45 mm high), solid, moderately high-spired biconic-fusiform; spire of more than 5 strongly noded whorls, about 40% of total shell height; protoconch incomplete, but seem- ingly polygyrate of more than 2 smooth whorls; whorl inflation generally constant, increasing from penulti- mate to last whorl; spire angle varies from 43° to 52°; sutures gently declivous, encroaching on previous whorls; last whorl with steep, moderately concave adapical slope, merging with strongly noded medial periphery; basal constriction moderately rapid below medial angulation; sculpture on last whorl of 12—14 variably sharp to axially extending nodes and weak spiral threads; growth lines with broad sinus, apex sit- uated at center of periphery on nodes; spire whorls with medial or just adapical of suture angulation bear- ing 13-14 strong tubercles, some slightly extending axially; aperture moderately narrow, sublenticular, with moderately short broadly notched, only slightly twisted, canal; columella long, mostly straight, bearing at least two oblique folds; outer lip moderately thick, smooth. Dimensions.—Holotype USNM 511889, height 39.5 mm, diameter of last whorl 20.5 mm; paratype USNM 511890, height 44.5 mm, diameter of last whorl 24.5 mm; paratype USNM 511891, height 38.5 mm, di- ameter of last whorl 23.5 mm. Type species.—Holotype USNM 511889: paratypes USNM 511890, USNM 511891, USNM 511892. Localities.—746, 1104, 1586, 1701. Material.—12 specimens. Stratigraphic distribution.—1134 to 1375 m. Discussion.—The siphonal canal of Paleopsephaea? 46 BULLETIN 367 nodoprosta n. sp. is relatively short and the peripheries of spire whorls and last whorl bear strong tubercles, compared to the latest Cretaceous type species, P. mu- tabilis Wade, 1926 (p. 123, pl. 40, figs. 4, 5, 8; Wenz, 1943, p. 1328, fig. 3772; Sohl, 1964, pp. 209-210, pl. 28, figs. 1-6) from the Gulf Coast of North America, but the slender outline, contracted whorls, and position of columellar folds are consistent with Paleopsephaea. Further, P. mutabilis has three columellar folds, but only two are visible on P.? nodoprosta. A possible fourth specimen of P.? nodoprosta, USNM 511892 (see Plate 6, figures 15, 16), is recorded from Loc. 746-4 and is incomplete, but is more slender with ax- ially extending peripheral nodes. Etymology.—Species named from the Latin prosto (equivalent to “stand out, project”) and the Latin no- dus (equivalent to “knot, swelling”) for its protruding tubercles or nodes. Subfamily FUSININAE Swainson, 1840? Genus TAIOMA Finlay and Marwick, 1937 Type species (by original designation).—Taioma tri- carinata Finlay and Marwick, 1937. Discussion.—The family-level placement of Taioma is contentious in the literature as this characteristic Austral Late Cretaceous to Paleogene group has been placed in its own family Taiomidae (Finlay and Mar- wick, 1937; Stilwell and Zinsmeister, 1992; Griffin and Hiinicken, 1994), Fasciolariidae: Taiominae (Wenz, 1943), Turridae: Thatcheriinae (Stilwell, 1994), and Fasciolariidae: Fusininae (Fricker, 1999). This confu- sion of relationship between Taioma and especially the Turridae and Fasciolariidae hinges on common fea- tures shared between these groups. Until a detailed study of this genus is completed, we concur with Wenz (1943) and Fricker (1999) that Taioma can be included in the Fasciolariidae as it shares a similar size and shell form, a long siphonal canal, a smooth columella and a similar growth line sinus that many fasciolarids have and can be confused with Turridae. However, the turrid genus Clinura Bellardi, 1875, combines features of Taioma and Turridae, and cannot be easily dismissed as unrelated. Taioma is recorded from the Late Cre- taceous to Eocene of Antarctica, Paleocene of New Zealand, Paleocene of Patagonia, and perhaps the Pa- leocene of Greenland (see Stilwell, 1994, for review). Taioma sobrali, new species Plate 9, figures 17—22 Diagnosis.—Moderately sized, rather tumid, pago- daform to broadly fusiform Taioma with at least 5 noded, low-keeled, pagodaform whorls; whorls par- tially enveloped by succeeding whorls, so that abapical part of whorl just below tubercled keels are hidden, marked by suture line; last whorl bicarinate, spiral sculpture weaker than growth lines, spiral ribs more spaced abapically below keel; growth lines separate and in some instances dissect tubercles; separated from likely descendent, 7. bicarinata Stilwell and Zins- meister, 1992, in having a smaller shell, weaker spiral sculpture and tubercle development. Description.—Shell medium-sized for genus (more than 39.0 mm high), solid, tumid, broadly fusiform to pagodaform; spire moderately high, of at least 5 nod- ed, keeled, slightly compressed, pagodaform whorls; whorl inflation very rapid from penultimate to last whorl; protoconch conical, small, paucispiral of seem- ingly two smooth whorls; spire angle approximately 75°; sutures partially clasping, abutting against keel of previous whorls; last whorl capacious, moderately in- flated, bicarinate, subsutural ramp very steep, short, shoulder steep and mostly straight, merging with a strong, projecting, noded keel with some 18—20 poorly to moderately defined tubercles, excavated below abapically, merging with secondary abapical angula- tion or rather week keel; basal constriction moderately rapid; spiral ornamentation weak of closely spaced, weakly beaded threads and rather broadly spaced cords on lower abapical half of last whorl below primary keel; growth lines strong, especially between each tu- bercle, broadly opisthocyrt, with moderately deep si- nus with apex situated midway on shoulder; spire whorls with strong subsutural keel bearing sharp nodes sitting directly on suture; whorls partially envelop suc- ceeding whorl, so that area of whorl abapical of keel hidden; aperture moderately open, broadly lenticular to subovate; siphonal canal incomplete; columella broadly concave, smooth, with moderately broad cal- lus; outer lip moderately thick with distinct sinus on shoulder. Dimensions.—Holotype USNM 511893, height 40.0 mm, diameter of last whorl 30.5 mm; paratype USNM 511894, height 23.5 mm, diameter of last whorl 16.5 mm; paratype USNM 511895, height 27.0 mm nearly complete, diameter of last whorl 21.5 mm. Types.—Holotype USNM_ 511893; paratypes USNM 511894, USNM 511895. Localities. —497, 1104 (type), 1105, 1130, 1431. Material.—19 specimens. Stratigraphic range.—1095 to 1375 m. Discussion.—Taioma sobrali n. sp. fills a gap in the Antarctic lineage of this Late Cretaceous to Eocene group. Until this record from the Sobral Formation, Taioma was recognized from the Campanian—Maas- trichtian deposits of Seymour, Humps and James Ross islands (Macellari, 1984; Stilwell and Zinsmeister, 1987c; Aguirre-Urreta and Olivero, 1992) and Eocene shallow-marine deposits of Seymour Island (Zinsmeis- EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 47 ter, 1982; Stilwell and Zinsmeister, 1992). A lineal re- lationship between 7. sobrali and T. bicarinata Stl- well and Zinsmeister, 1992 (pp. 137-138, pl. 19, figs. a-d) is highly probable, as these taxa are extremely close morphologically. Minor differences in size of shell, tubercle development and spiral ornamentation serve to distinguish these Antarctic taxa. Taioma so- brali has a smaller shell, less developed tubercles cre- ating a slightly weaker keel, and weaker spiral sculp- ture, compared with 7. bicarinata. Although the ho- lotype and two other recorded specimens of 7. sobrali are slightly crushed from compaction, a bit abraded and slightly incomplete, it would be rather difficult to differentiate these specimens from others of 7. bicar- inata if they were recovered from the same unit. Taio- ma charcotianus (Wilckens, 1910) (pp. 91—93, pl. 4, figs. 6a, b, 8, 11; Macellari, 1984, pl. 35, figs. 6—8; Fricker, 1999, pp. 202-205, pl. 6, figs. 6, 7) from the Campanian—Maastrichtian of Antarctica is much closer in age to T. sobrali than this species is to 7. bicarinata, but a close relationship is not probable, as 7. charco- tianus has a very high-spired fusiform shell with more centrally located keels, unlike the tumid nature of 7. sobrali and T. bicarinata. The New Zealand Paleocene type species, T. tricarinata Finlay and Marwick, 1937 (p. 72, pl. 10, figs. 5-7; Wenz, 1943, p. 1256, fig. 3579; Fleming, 1966, p. 320, pl. 111, figs. 1361-1363; Stilwell, 1994, pp. 1087-1090, pl. 76, figs. 10-17), also has a high spire and is tricarinate, unlike 7. so- brali. Of note, Clinura sp. 1 of Kollmann and Peel (1983) (p. 97, fig. 220, especially C, D) from the Pa- leocene of Greenland may be a congeneric form, but the position of the keel on the spire whorl is more adapically positioned above the suture and has stron- ger spiral sculpture, but weaker growth lines, com- pared with 7. sobrali. The greatly disjunct, bi-polar distribution of Taioma during the Paleocene is difficult to reconcile if Clinura sp. | proves to be more appropriately allocated to Taioma. Perhaps Taioma had a more widespread dis- tribution during the Late Cretaceous than previously thought, or the groups are indeed homeomorphs. Etymology.—Species named for its presence in the Sobral Formation. Superfamily VOLUTOIDEA Rafinesque, 1815 Family VOLUTIDAE Rafinesque, 1815 Subfamily ZIDONINAE Pilsbry and Olsson, 1954 Genus ZYGOMELON Harasewych and Marshall, 1995 Type species (by original designation).—Zygomelon zodion Harasewych and Marshall, 1995. Discussion.—The stratigraphic range of Zygomelon is extended into the early Paleocene with the descrip- tion herein of Z. apheles n. sp. from the Sobral For- mation. The genus is represented only by Z. suropsilos (Stilwell and Zinsmeister, 1992), from the Eocene La Meseta Formation (Units V—VI), and the New Zealand type species, Z. zodion Harasewych and Marshall, L995: Zygomelon apheles, new species Plate 10, figures 4—10 Diagnosis.—Teleoconch of 6—7 smooth, rounded or weakly angulated whorls, callus thin, columella with a single oblique fold, and siphonal fasciole inconspic- uous. Description.—Shell of medium size (up to 77.2 mm), moderately thin for size, biconic, with fusiform spire, rounded anteriorly; protoconch not preserved: teleoconch of up to 7 convex, rounded or weakly an- gulated whorls. Suture adpressed; shell surface smooth except for thin axial growth lines; aperture ovate, ta- pering anteriorly and posteriorly; siphonal fasciole weak and inconspicuous on some specimens; outer lip smooth and simple; columella smooth with one oblique fold, located in the middle or slightly below the middle. Dimensions.—Holotype USNM 511896, height 53.0 mm, diameter of last whorl 25.0 mm; paratype USNM 511897, height 58.0 mm, diameter of last whorl 26.0 mm; paratype USNM 511898, height 70.5 mm, di- ameter of last whorl incomplete; paratype USNM 511899, height, 40.0 mm, diameter of last whorl 20.0 mm; paratype USNM 511900, height 47.0 mm nearly complete, diameter of last whorl 23.0 mm. Types.—Holotype USNM 511896; paratypes USNM_ 511897, USNM 511898, USNM 511899, USNM 511900. Localities.—9, 746, 1104, 1192, 1431, 1442, 1601. Stratigraphic range.—1124 to 1375 m. Material.—13 specimens. Discussion.—Zygomelon apheles n. sp. is distin- guished from the Recent New Zealand type species, Zygomelon zodion Harasewych and Marshall, 1995 (pp. 145-150, figs. 1-13), in having a larger size, thicker shell, lack of spiral and axial sculpture, other than growth lines, single oblique columellar plait, and narrower aperture tapering anteriorly and posteriorly. Etymology.—Named from the Greek apheles (equivalent to “‘even, smooth, simple” for its smooth, unornamented shell. Family MITRIDAE Swainson, 1831 Subfamily MITRINAE Swainson, 1831 Genus MITRA Swainson, 1831 Type species (by tautonomy).—Voluta mitra Lin- naeus, 1758. 48 BULLETIN 367 Subgenus EUMITRA Tate, 1889 Type species (by subsequent designation, Cotton, 1957).—Mitra alokiza Tenison-Woods, 1880. Mitra (Eumitra?) antarctmella, new species Plate 10, figures 11—14 Diagnosis.—Moderately sized mitrid with a ovately fusiform outline and characteristic telescoped whorl profiles; spire subgradate; sculpture poorly defined of weak spiral threads and mostly orthocline growth lines: short canal with distinct notch; columella with two folds (a possible adapical third poorly preserved): distinguished from Mitra (Ewmitra) sadleri Stilwell and Zinsmeister, 1992, in having a higher spire, more elongate last whorl, weaker spiral sculpture and dis- tinct telescoped whorls. Description.—Shell_ medium-sized for genus and subgenus (at least 33.0 mm high), moderately robust, moderately high-spired elongate-fusiform; spire of at least 3, gradate, telescoped, subsuturally swollen, sub- quadrate whorls; spire 38% of total shell height; whorl inflation relatively rapid from penultimate to last whorl; spire angle acute, approximately 35°; sutures weakly impressed to nearly channeled; protoconch un- known; last whorl capacious, but only moderately in- flated axially, with subsutural swollen ‘‘collar” just ab- apical of suture, becoming concave with a constriction between swollen “collar” and lower abapical swollen region followed by moderate tapering of siphonal ca- nal; sculpture poorly defined on holotype, but of weak spiral threads and mostly orthocline growth lines; only growth lines on spire whorls; aperture nearly half of length of shell, narrowly lenticular; canal short, with moderately broad spout; columella gently concave, with at least two, closely spaced, moderately devel- oped, columellar folds, a possible third adapical plait present, but poorly preserved on holotype, and a nar- row callus; outer lip thin. Dimensions.—Holotype USNM 511901, height 33.0 mm, diameter of last whorl 16.0 mm; paratype USNM 511902, height 19.5 mm, diameter of last whorl 9.5 mm. Types.—Holotype USNM 511901; paratype USNM 511902. Localities.—1108, 1635. Material for both localities was collected as surface float. Precise stratigraphic ho- rizon can only be approximated: locality 1108~1210 m, locality 1635~1175 m. Material.—Two specimens. Discussion.—The holotype and paratype of Mitra (Eumitra?) antarctmella n. sp. are coarsely preserved and worn, so that detail of ornamentation and colu- mella are ill defined. Thus, although clearly a member of the Mitra Lamarck, 1798, group, a subgenus-level assignment is tentative at the time of this writing. The specimens have a moderately high-spired fusiform out- line, at least two folds (a possible adapical third poorly preserved on the holotype), a subgradate spire, irreg- ular growth lines, a distinct notch, a slightly produced canal, all characters consistent with Mitra (Eumitra) (see review by Cernohorsky, 1970, pp. 36-37). If pos- itively identified, this specimen is the oldest member of this Tertiary group that became extinct in Australia and New Zealand during the early Pliocene. Previous- ly, the oldest record was from the Eocene of Antarc- tica, where two species were described, M. (E.) mon- oplicata and M. (E.) sadleri, by Stilwell and Zins- meister (1992) from the La Meseta Formation. Mitra (Eumitra?) antarctmella n. sp. is most closely allied with M. (E£.) sadleri Stilwell and Zinsmeister, 1992 (p. 148, pl. 21, fig. e) from Units I—V of the La Meseta Formation, but the Sobral species has a higher spire, more elongate last whorl with a swollen subsu- tural collar, and also spire whorls that are more su- bquadrate and telescoped. The sculpture and whorl shape of M. (E.?) antarctmella is also reminiscent of M. (E.) waitematiaensis (Powell and Bartrum, 1929) (see Cernohorsky, 1970, p. 37, pl. 3, fig. 5) from the Miocene of New Zealand, but the Antarctic species is slightly smaller with more telescoped whorls and more developed subsutural *‘collars.” Etymology.—Species named from the Latin me//lum (equivalent to “‘collar’), for its swollen, collar-like subsutural inflation and for its Antarctic occurrence. Order STYLOMATOPHORA A. Schmidt, 1865 Suborder TOXOGLOSSA Troschel in Troschel and Ruthe, 1848 Superfamily CONOIDEA Rafinesque, 1815 Family TURRIDAE Swainson, 1840 Subfamily PPEUDOTOMINAE Bellardi, 1875 Genus MARSHALLARIA Finlay and Marwick, 1937 Type species (by original designation).—Verconella spiralis Allan, 1926. Discussion.—A solely Austral group, the geograph- ic range of Marshallaria Finlay and Marwick, 1937, is expanded herein to include the Paleocene of Ant- arctica, previously recorded from the late early Paleo- cene to late early Miocene of New Zealand (Beu and Maxwell, 1990) and mid-Paleocene to early Oligocene of Victoria, Australia (Long, 1981; Darragh, 1997). Beu and Maxwell (1990, p. 124) stated that the few records of this turrid indicate that species during the Tertiary favored mid-shelf to upper bathyal zones; EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 49 however, M. multicincta (Marshall, 1917) from the New Zealand Paleocene and M. variegata n. sp. from the Antarctic Paleocene lived in nearshore, subtidal en- vironments along the inner shelf suggesting a possible gradual shift from shallower to deeper waters through- out the Tertiary. Further research on early Tertiary turrids is required to clarify the relationships of seemingly closely related groups such as Marshallaria and the Tertiary Euro- pean Pseudotoma Bellardi, 1875. Species of Marshal- laria have a slightly more produced siphonal canal and a narrower callus on the inner lip compared to species of Pseudotoma which have shorter less produced si- phonal canals and broader labial calluses. Additional study on these taxa may result in the abandonment of Marshallaria or at least reduction to subgenus level especially in light of the marked similarities between these two groups. Of note, another closely related group, Austrotoma Finlay, 1924, has a ridge-margined fasciole and a pronounced siphonal notch compared with Marshallaria (Beu and Maxwell, 1990, p. 124). Marshallena Allan, 1927, is another closely related taxon, but Marshallena has a more poorly defined si- nus and a regularly conic polygyrate protoconch in contrast to Marshallaria which has a more defined shallowly concave sinus on the adapical shoulder slope and polygyrate dome-shaped protoconch (see Powell, 1966, p. 27). Marshallaria variegata, new species Plate 10, figures 17—22 Diagnosis.—Relatively big Marshallaria with mod- erately high spire of at least 4.5 angulate, subtrapezi- form whorls; whorls partially envelop succeeding whorls variably, so that angulation on penultimate whorl either nearly abutting suture or well above adap- ically; spire angle varies from 56° to 67°; last whorl with strong medial angulation, bearing poorly devel- oped tubercles and weaker secondary one just below at onset of basal constriction; spiral sculpture stronger than growth lines; callus narrow, but rather thick; notch barely developed; outer lip moderately thick with sinus on shoulder; distinguished from closely al- lied type species, M. spiralis (Allan, 1926) in having a stronger peripheral angulation and an additional sec- ondary angulation below abapically, lower spire, and a longer, steeper, more concave adapical ramp on shoulder. Description.—Shell large for genus (up to 46.5 mm high), moderately thick-shelled, robust, relatively tu- mid, bioconic-fusiform; spire moderately high of at least 4.5, angulate, moderately compressed, subtrape- ziform whorls that partially envelop succeeding whorl; protoconch relatively large, dome-shaped, probably polygyrate, smooth, incomplete on available material; spire angle varies from 56° to 67°; whorl inflation rel- atively rapid, especially from penultimate to last whorl; sutures slightly impressed, gently declivous; last whorl capacious, biangulate, adapical ramp steep, moderately long, concave, merging with strong pe- ripheral angulation, bearing weak axially extending tu- bercles, and lower abapical secondary angulation, marked by onset of basal constriction, gently concave between angulations; sculpture of ~37—40 evenly and closely spaced spiral cords, more bunched on adapical sutural ramp on last whorl, and sinuous growth lines: sinus moderately concave on shoulder slope; spiral sculpture stronger than growth lines; ornamentation on spire whorls of ~15 spiral ribs and ~20 rather poorly defined tubercles on abapically positioned angulation; angulation on penultimate whorl variably positioned either just above suture or occupying a more medial whorl position; aperture over half the length of shell at 57% of shell height, moderately open, sublenticular with parietal canal and short, straight, virtually un- notched canal; columella long, concave above, straight below on pillar, callus narrow, thick, even along col- umella; fasciole poorly developed; outer lip moderate- ly thick with sinus on shoulder. Dimensions.—Holotype USNM 511904, 46.5 mm, diameter of last whorl 28.0 mm; paratype USNM 511905, height 45.0 mm, diameter of last whorl 28.5 mm; paratype USNM 511906, height 41.5 mm, di- ameter of last whorl 27.0 mm. Types.—Holotype USNM_ 511904; paratypes USNM 511905, USNM 511906. Locality.—746 (type), 1104, 1119, 1431, 1548. Material.—16 specimens. Stratigraphic range.—1096 to 1375 m. Discussion.—Marshallaria variegata n. sp., the old- est member of this group, fits comfortably in this Pa- leocene to Miocene genus, and greatly expands its geographic range. The late Eocene type species, M. spiralis (Allan, 1926) (p. 340, pl. 76, fig. 9: Wenz, 1943; p: 1389° fis: 3925;"Powell, 1966; p27; pl. 1, fig. 13; Beu and Maxwell, 1990, p. 124, pl. 8, fig. x; Maxwell, 1992, p. 155, pl. 22, figs. b, c, I) has a higher spire, steeper and longer shoulder, and single angula- tion on the last whorl, compared with M. variegata. These two taxa are closely allied forms. Marshallaria multicincta (Marshall, 1917) (p. 457, pl. 35, fig. 30: Finlay and Marwick, 1937, p. 84, pl. 11, figs. 10-12; Fleming, 1966, p. 368, pl. 135, figs. 1588-1590) (= Daphnella ovata Marshall, 1917, p. 457, pl. 35, figs. 28, 29) trom the New Zealand Paleocene and M. tu- mefacta Darragh, 1997 (p. 82, 84, fig. SQ, X. Y) from the Australian Paleocene are not closely related forms, but Marshallaria sp. a of Darragh (1997) (p. 84, fig. 50 BULLETIN 367 5M, N) from the early Eocene is reminiscent of M. variegata, differing in the Australian species having a more tumid shell and a steeper, more concave, longer adapical ramp. Although the Turridae is speciose in the Antarctic Eocene, no Marshallaria species have been recorded, although Austrotoma oliveroi Stilwell and Zinsmeister, 1992 (pp. 155-156, pl. 23, figs. a—d) comes closest to M. variegata, but has a much weaker peripheral angulation, narrower callus, and longer steeper adapical slope. Further, the available material of M. variegata reveals some interesting intraspecific variation, mainly in shell outline (either tumid or less so), strength of tubercles on angulation, and position of angulation on penultimate whorl (e.g., extent to which last whorl envelops penultimate whorl). Etymology.—Species named from the Latin varie- gatus (equivalent to “‘of different sorts”) for its vari- able nature in terms of shell outline and especially or- namentation. Subfamily TURRINAE Swainson, 1840 Genus COSMASYRINX Marwick, 1931 Type species (by original designation).—Cosmasy- rinx monilifera Marwick, 1931. Subgenus THOLITOMA Finlay and Marwick, 1937 Type species (by original designation).—Tholitoma dolorosa Finlay and Marwick, 1937. Discussion.—Recent work on Cosmasyrinx (Tholi- toma) indicates that this subgenus is more widespread than previously thought. The presence of the group in the Paleocene of Antarctica extends its range from middle to late Eocene, recorded by C. brychiosinus Stilwell and Zinsmeister, 1992. Darragh (1997) de- scribed C. (7.) levicristata from the Paleocene Pebble Point Formation of Victoria, Australia, and Cosmasy- rinx (Tholitoma) sp. of Long (1981) is the only known late Eocene species from Victoria, Australia. In New Zealand, Cosmasyrinx (Tholitoma) ranges from late early Paleocene to late Eocene (see Finlay and Mar- wick, 1937; Maxwell, 1992: Stilwell, 1994). Cosmasyrinx (Tholitoma) antarctigera, new species Plate 10, figures 15, 16 Diagnosis.—Small- to medium-sized for group, somewhat fusiform to pagodaform; spire angle about 63°; last whorl inflated with strong angulation or keel, bearing about 18 strong tubercles or nodes, some ax- ially extending, and spiral ornamentation of about 25 gemmuliform threads; apex of moderately deep anal sinus on middle part of shoulder slope, positioned just above appearance of tubercles; distinguished from type species, Cosmasyrinx (Tholitoma) dolorosa Finlay and Marwick, 1937, in having a more tumid pagodaform outline, stronger keel, weaker spiral ornamentation, and less developed subsutural submoniliform spiral cord. Description.—Shell small- to medium-sized for ge- nus and subgenus, moderately thin, polished in well- preserved specimens, moderately fusiform to pagoda- form; spire moderately high of at least four keel whorls, bearing strong tubercles; whorl inflation rapid; spire angle approximately 63°; suture moderately im- pressed, gently descending; protoconch moderately large, incomplete on types, but apparently polygyrate, dome-shaped; last whorl capacious, strongly unicari- nate with prominent keel bearing ~18 moderately de- veloped, slightly axially extending, collabral tubercles, and rather weak sculpture of 25 somewhat irregular, gemmuliform, closely spaced riblets; adapical shoulder slope of last whorl steep, slightly concave, merging with strong peripheral angulation and contracting rap- idly abapically below to moderately long neck; pres- ence of subsutural riblets poorly developed, closely spaced gemmules on margining submoniliform inflat- ed cord; gemmules on subsutural cord trend opposite to tubercles on periphery and generally follow growth lines; growth lines moderately strong with deep sinus midway on shoulder slope; spire whorls strongly car- inate with 16 nodules on slightly inflated keel sitting directly on suture and some 20 weak spiral threads; aperture long, narrow, sublenticular; outer lip thin; anal sinus moderately deep, U-shaped, apex situated just abapical of midpoint on adapical ramp, just above the appearance of collabral tubercles. Dimensions.—Holotype USNM 511907, height 7.0 mm, diameter of last whorl 5.5 mm; paratype USNM 511908, height 6.5 mm, diameter of last whorl 4.5 mm. Types.—Holotype USNM 511907; paratype USNM 511908. Localities.—496, 1519 (type), 1535. Material.—Three specimens. Stratigraphic distribution.—1073 to 1179 m. Discussion.—Cosmasyrinx (Tholitoma) antarctig- era n. sp. is the oldest recorded member of the group, as it is present in the early Danian of Antarctica. The next oldest species is the type, C. (7.) dolorosa Finlay and Marwick, 1937 (pp. 85—86, pl. 12, figs. 6, 7; Flem- ing, 1966, p. 364, pl. 133, figs. 1570-1572; Powell, 1966, p. 37, pl. 3, fig. 22; Stilwell, 1994, pp. 1059— 1063, pl. 75, figs. 1-8), from the late early Paleocene of New Zealand, which differs from C. (7.) antarctig- era in having a slightly larger, more slender, more high-spired shell, a stronger subsutural moniliform spi- ral cord, and a more prominent keel. Another closely EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 51 related species is the mid-Paleocene species, C. (7-) levicristata Darragh, 1997 (p. 82, fig. SR, V, W, Z) from Victoria, Australia, but differs from the Sobral Formation species in having a more slender, higher spired shell, and fewer, more spaced collabral tubercles on the peripheral angulation. Cosmasyrinx (Tholitoma) antarctigera is a most likely candidate as the ancestor of C. brychiosinus Stilwell and Zinsmeister, 1992 (p. 159, pl. 22, figs. i-l), from Units HI—VII of the La Meseta Formation of Seymour Island, and is separated from the younger Eocene C. brychiosinus in having a larger more inflated last whorl, a shorter spire, finer spiral ornamentation, and stronger tubercles on the keel. Etymology.—Species named from the Greek geras (equivalent to “‘old”’) for its earliest recorded occur- rence in Antarctica. Subclass OPISTHOBRANCHIA Milne-Edwards, 1848 Order CEPHALOSPIDEA Fischer, 1883 Suborder ACTEONOIDA d Orbigny, 1842 Superfamily PHILINOIDEA Gray, 1850 Family CYLICHNIDAE A. Adams, 1850 Genus CYLICHNANIA Marwick, 1931 Type species (by original designation).—Cylichnan- ia bartrumi Marwick, 1931. Discussion.—Cylichnania Marwick, 1931, is re- corded from Antarctica for the first time, previously known only from the Late Cretaceous to late Pliocene? of New Zealand (Stilwell, 1994) and mid-Paleocene to late Eocene of Australia (Darragh, 1997). Cylichnania is distinct in having a subcylindrical outline, ornamen- tation of even, low, flat-topped spiral cords, and its deep apical depression, with labrum extending well adapically to the labium (Beu and Maxwell, 1990, p. 238). Species of closely related Cylichna Loven, 1846, are characterized by small and cylindrical shells with a truncated abapical end, an involute spire reflecting a tightly coiled and multi-whorled shell, a small apical concavity and a columella with a single oblique fold (Abbott, 1974, p. 314; cf Stilwell and Zinsmeister, 1992, p. 173). Species of Cylichnania are eurybathyal, ranging from at least inner shelf to upper bathyal en- vironments (cf. Beu and Maxwell, 1990, p. 238). Pa- leocene representatives C. impar Finlay and Marwick, 1937, and Cylichnania n. sp. of Stilwell (1994), from the Wangaloa and Kauru formations of New Zealand are present in sandstones interpreted to have been de- posited along the inner shelf in a protected environ- ment (Stilwell, 1994, p. 1159). Cylichnania cf. C. im- par described below is also from an inner shelf envi- ronment. Cylichnania cf. C. impar Finlay and Marwick, 1937 Plate 10, figure 23 Description.—Shell average-sized for genus (10 mm high), thin, moderately slender, subcylindrical to narrowly ovate, involute, apex sunken (eroded on available specimen), subhorizontally truncated; orna- mentation of many, closely spaced, slightly wavy, re- volving spiral riblets (~15 per mm), generally weaker centrally on last whorl; growth lines weak becoming slightly stronger on edge of labrum, mostly orthocline apart from tendency to become weakly prosocline abapically near base; aperture very narrow, constrict- ing with parallel sides adapically, widening greatly at base; aperture at abapical end ovate; columella mostly straight, short, slightly truncated below, bearing a moderately developed plait, situated flush against col- umellar wall at base (covered by matrix more adapi- cally); umbilicus poorly developed; outer lip thin, probably finely crenulated, partially fragmented on available specimen; large break in shell during growth (damage by lip peeler?), which affected growth only slightly pathologically, in which spiral riblets along break are “‘warped.” Dimensions.—USNM 511915, height, 10.0 mm, di- ameter of last whorl 5.5 mm. Type.—Hypotype USNM 511915. Localities. —1519, 1538. Material.—Three specimens. Stratigraphic range.—1073 to 1104 m. Discussion.—Only one opisthobranch gastropod has been reported from the Paleocene of Antarctica. It is surprising that acteonid and ringiculid gastropods are absent in Antarctic Paleocene deposits, being present in uppermost Cretaceous units in Antarctica and also in coeval shallow-marine deposits of New Zealand, Australia, and South America, where opisthobranchs are moderately to highly diverse. The sole specimen belongs to the Cylichnidae and has a close affinity with Cylichnania impar Finlay and Marwick, 1937 (p. 93, pl. 13, fig. 1; Fleming, 1966, p. 382, pl. 142, fig. 1690; Stilwell, 1994, pp. 1159-1161, pl. 81, figs. I- 3) and Cylichnania n. sp. of Stilwell (1994, pp. 1161— 1163, pl. 81, figs. 4, 5, 9, 13, 18) from the late early Paleocene of New Zealand, differing slightly in orna- mentation and shell outline. The Antarctic species has a slightly smaller, less ovate and more cylindrical shell with finer and more abundant, wavy spiral riblets, compared to C. impar and Cylichnania n. sp. of Stil- well (1994), but overall is more comparable to C. 1m- par. Although probably a new species, the Antarctic species is left in open nomenclature until more mate- rial is discovered. 52 BULLETIN 367 Text-figure 5.—Stratigraphic plane analysis is a graphical tech- nique that produces two-dimensional geometric projections to vi- sualize simultaneously spatial and stratigraphic distribution of fossil occurrences using two intersecting planes (Reference and Strati- graphic) with a datum, which is defined by a specified elevation. The Reference Plane is a vertically oriented plane parallel to the strike of the sequence and is used to locate the spatial occurrence of x, y, and z coordinates of locality Z, where the y-axis is the strike of the sequence, the x-axis is normal to y, and the vertical z-axis defines the elevation. The Stratigraphic Plane is an arbitrarily des- ignated plane oriented parallel to the regional strike and dip of the bedding, where A is the angle of dip. X is the distance from the Reference Plane to Z and Z, represents the stratigraphic interval between locality Z and the Stratigraphic Plane. APPENDIX MAASTRICHTIAN/DANIAN SEYMOUR ISLAND DATA BASE William J. Zinsmeister The controversy about the nature, sequence, and timing of the extinction event at the K-T boundary has revealed several inherent limitations in the traditional biostratigraphic methods. The foundation of biostratig- raphy has been the measured section. Range data from measured sections, by convention, are combined into composite range charts that are intended to represent the temporal ranges of the taxa portrayed in the chart. An inherent problem with the use of measured sections is the integration of data that do not occur along any of the sections. The traditional approach when con- structing composite range figures is to determine the stratigraphic interval between an isolated fossil locality and a horizon that can be correlated into the measured section. In those cases where it is not practical or pos- sible to assign a locality to a known horizon, the strati- graphic location of the fossil occurrence is, as a con- sequence, estimated. In both approaches, the accuracy of the stratigraphic location of an isolated fossil local- ity is less than that obtained along a measured section. Another serious limitation in presenting occurrence data in composite range charts is the loss of the geo- graphic component with the data set. Although the data represented in a composite range chart may have = tanAxX N | Z, = cosr|Z,) Text-figure 6.—Determination of Z, values (relative stratigraphic occurrence): Z, location of the locality, is equal to the elevation at that point; X, distance from Z to the Reference Plane RP; A, angle of dip of the Stratigraphic Plane (equal to dip of bedding); Z,, ver- tical distance from Z located on the datum to the stratigraphic plane; Z,, the stratigraphic distance from Z to the stratigraphic plane. If Z is located above the datum (Z,), the value of Z’ is equal to the difference between the elevation Z, and Z, (when Z is located on the datum, Z, equals Z,). The conversion of spatial to stratigraphic data is expressed by the formulae to the right of the figure. been based on a number of measured sections from a broad geographic area, the spatial components within the data are suppressed when the data are merged in a single-dimensional (temporal) range chart. Zinsmeis- ter (1996) discussed the need to evaluate biostrati- graphic data from a spatial perspective and presented the first two-dimensional figures (spatial and _strati- graphic) of the distribution of ammonites from Sey- mour Island. Zinsmeister (1998b) proposed a graphical technique, Projection Plane Analysis, which uses or- thographic projections to locate simultaneously spatial and stratigraphic fossil occurrences. This technique al- lows for the determination of the relative stratigraphic occurrence of any locality not located along a mea- sured section. For a detailed description of the tech- RP A Stratigraphic Plane Projection D Reference Plane Projection SFero Text-figure 7.—Geometric relationship of stratigraphic plane with spatial occurrence of location data. Regardless of the location of the data point, when the data are projected against the Stratigraphic Plane, the relative stratigraphic position of the data point in relation to other data points may be determined. Stratigraphic projections also highlight any stratigraphic or structural anomalies which may compromise the data set. EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. Nn ies) 1000 400 200 0) 1000 2000 3000 4000 5000 6000 7000 8000 1000 400 200 3000 4000 5000 6000 7000 X 8000 9000 10000 11000 12000 Text-figure 8.—Two-dimensional projections of Maastrichtian/Danian fossil localities on Seymour Island. A, Z,Y projection of occurrence data along strike. B, projection of the data in A in a Z,X projection perpendicular to strike. Z,, stratigraphic occurrence (m) of localities; Y, distance (km) along strike; and X, distance (km) perpendicular to strike and from the intersection of the Stratigraphic and Reference planes with the datum horizon. The Stratigraphic Plane corresponds to the upper margin of the figures. Solid circles, Maastrichtian, and crosses, Danian localities in the Lopez de Bertodano Formation; open circles, Danian localities in the Sobral Formation. nique refer to Zinsmeister (2001). A brief summary of the Stratigraphic Plane Analysis is provided here as an introduction to stratigraphic data presented in this ap- pendix. The objectives of Projection Plane Analysis are to increase precision in the location of stratigraphic data not located along a measured section and to provide a technique to retain the spatial component in the eval- uation of a biostratigraphic data set over large geo- graphic areas. The technique is based on patterns pro- duced by orthographic projections of biostratigraphic data using two intersecting planes (Reference and Pro- jection planes) with a datum, which is defined by a specified elevation, typically sea level (Text-fig. 5). The Reference Plane is used to locate fossil localities spatially while the Projection Plane is a stratigraphic plane employed to locate the stratigraphic occurrence (Zn value) of a locality (Text-fig. 6). In traditional bio- stratigraphy, the data are plotted relative to a strati- graphic horizon, such as an ash bed or lithologic con- tact, which is considered to be a time horizon. The possibility exists that subtle surface relief along the stratigraphic horizon caused either by subtle changes of attitude or the bedding planes or pre-depositional erosion may compromise the stratigraphic integrity of data projected this way. Biostratigraphic errors caused by subtle surface relief along the horizon are magnified as the geographic area increases. As an example, a half of one degree of slope on a surface used to plot bio- stratigraphic data will produce an error of 8.7 m over 54 BULLETIN 367 Table 3.—Maastrichian-Danian locality registry. Geographic and relative stratigraphic locations (Z,,) of Maastrichtian and Danian lo- calities from the Lopez de Bertodano and Sobral formations. All Maastrichtian localities from the Lopez de Bertodano Formation have been included because a number of the Danian taxa have rang- es that extend into the Maastrichtian. The X, Y, and Z values in Table 3 provide the geographic location of each locality. The coor- dinates are based on the location of the Reference Plane, which was oriented N38°30’E. The intersection of the Stratigraphic and Refer- ence planes is located 525 m east of conical hill (56°42'54.2” and 64°15'75.5") located at the head of Cross Valley. The point at the head of Cross Valley is an arbitrary geographic point to locate the intersection of the Reference and Stratigraphic planes and to insure that all the localities would be located below the Stratigraphic Plane. The conical hill is located at a point 7000 m from the 0 m point on the Reference Plane. See Zinsmeister (2001) for in-depth discussion of the location and orientation of the Reference and Stratigraphic planes when using Stratigraphic Plane Analysis technique. Locality Ys Xx Zi Tas 9 7010 5550 47 1167.94 377 4690 8320 77 770.78 38 4720 7890 82 832.30 458 6440 7210 25 919.08 459 6170 8150 3) 769.01 468 6530 6970 36 963.16 477 5920 6055 30 1058.45 485 5880 6110 36 1056.12 496 7000 5490 sil 1179.42 497 7110 3810 22 1369.31 631 6630 5660 40 1138.29 648 6980 5500 55 1181.68 724 6030 8160 24 784.60 T29) 5930 9060 51 692.54 746 1950 3870 5 1134.22 754 5030 7310 48 885.08 755 4490 7580 82 862.98 756 5450 7530 43 866.53 TST: 5560 7040 35 925.34 758 5650 7460 34 873.15 759 4620 7130 82 926.22 760 4600 6950 83 949.59 761 4600 7170 81 919.27 762 4590 7190 82 917.29 763 6450 7080 29 940.04 764 4680 7190 79 917.91 765 6130 7070 52 955.59 767 4630 10360 15 444.17 768 4930 10260 30 483.56 769 4650 10800 58 430.94 770 4750 6780 92 986.36 ah 6100 6880 69 996.08 TID 4900 8620 45 708.53 TI3 5400 7460 38 868.91 774 6030 6770 76 1015.19 775 6580 6970 pHi] 955.47 776 4070 7280 23 825.14 777 6060 7090 40 939.14 778 5980 7090 31 927.90 779 5990, 6120 29 1051.14 780 6050 7740 37 852.16 781 5980 7730 39 853.40 783 5750 5970 38 1072.17 785 6000 7770 32 841.89 Table 3.—Continued. Locality 786 860 884 1104 1105 1109 1110 1116 1119 1120 1125 1128 1130 1131 1133 1134 1135; 1136 1137, 1138 1139 1140 1143 1146 1148 1150 1151 1157 1159: 1161 1164 1166 1167 1170 1171 1172 1173 1174 1175 1176 1177 1178 1180 1182 1183 1184 1185 1186 1187 1188 1189 1190 1192 1194 1195 1196 1197 1198 1199 1201 1204 ¥ 6060. 3990, 3200 7140 7080 1460 1730 2060 1970 1970 2020 1590 2150 2090 1570 1360 1610 1990 1850 1950 2260 2240 1610 2510 2670 1380 1640 1740 1950 5420 1990 1970 1980 1990 2260 1960 1900 1870 1930 2200 1930 2190 1890 2000 1860 1990 1990 1420 2230 1740 1980 2220 1750 2500 2200 1970 1610 2170 2280 1960 1850 Xx 7820 10080 6020 3790 3790 6240 6460 5540 5440 5175 5350 6310 4510 4690 4310 4290 4310 4250 4250 4365 4400 4440 6240 6810 4210 6680 4990 5330 6040 6100 6100 5320 6090 5540 5200 6720 6620 6130 5470 4615 5550 4230 5670 5090 5190 4760 5100 5030 5220 4670 Z n 828.26 451.01 1022.06 1375.46 1369.29 855.43 845.44 962.53 964.97 1031.83 1012.34 858.81 1094.66 1065.89 1087.34 1083.14 1091.90 1136.32 1125.70 1107.16 1145.11 1133.82 867.12 865.07 1215.89 812.34 1001.28 993:59 925.14 1050.70 920.86 1019.10 920.54 957.28 992-712 966.84 977.22 1001.83 1014.07 977.47 1020.61 986.99 1019.81 915.30 1008.94 1031.81 808.28 821.71 927.46 961.68 1070.85 961.68 1124.00 988.52 1035.83 1030.89 1032.95 1033.75 1054.24 1026.41 1050.78 Table 3.—Continued. EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. Locality BY Xx 1205 1600 4750 1206 2470 5630 1207 1415 4850. 1211 5450 6130 1404 1750 5650 1412 1980 5180 1420 4030 6370 1424 1530 6270 1425 1370 6250 1426 3130 10190 1427 3970 6680 1428 5250 6190 1429 4300 6180 1430 4580 5890 1431 2980 4620 1432 2970 4940 1433 2840 4515 1434 4850 5680 1435 3180 4660 1436 1720 6390 1437 3960 6780 1438 4020 6390 1439 3850 6910 1439 3840 6790 1440 1870 5190 1441 4400 7050 1442 3050 4710 1443 4260 6160 1448 4020 6500 1451 6450. 6490 1452 3680 5970 1453 2540 6090 1454 2840 5270 1455 2780 5810 1456 3530 5130 1457 2430 4950 1458 2800 5900 1460 4280 6255 1461 4420 6280 1462 4370 6330 1463 4380 6360 1464 4340 6340 1465 4300 6285 1466 2630 5340 1467 2730 5220 1468 2160 5890 1469 2600 5920 1470 2680 6140 1471 2700 6160 1472 1790 6530 1473 4000 5710 1474 1830 5140 1475 1810 5135 1476 3840 6880 1477 4250 6680 1478 1490 5270 1479 1480 5220 1480 1430 5260 1481 950, 5370 1482 990 5370 1483 6210 5740 43 101 126 Z in 1037.56 988.98 1006.71 1039.9] 929.21 1031.79 1013.94 856.12 822.44 408.97 958.42 1026.32 1037.33 1098.20 1144.26 1110.44 1174.05 1165.61 1165.45 866.71 962.94 1010.92 941.16 960.12 1024.72 931.48 1140.34 1040.17 987.83 1029.92 1047.31 958.51 1052.02 1011.92 1154.22 1060.38 1042.09 1027.80 1030.50 1022.95 1023.48 1020.40 1024.79 1038.37 1030.43 935:37 996.69 967.87 968.39 827.31 1110.49 1016.77 1028.06 953.48 980.70 985.29 989.09 972.74 903.36 = 909°10 1125.14 55 Table 3.—Continued. Locality AY; x LZ: Li 1484 2700 4470 61 1156.30 1485 2580 7670 54 730.50 1486 2430 8020 48 670.93 1487 2460 8090 52 667.60 1488 2830 8120 11 643.75 1489 3020 10250 15 383.58 1490 3970 9830 22 491.23 1491 4250 9950 29 495.08 1492 3800 8710 61 666.35 1493 5080 6890 84 976.70 1494 4350 6275 86 1029.19 1496 5350 6210 32 1022.25 1497 5340 6110 45 1047.68 1498 5300 6180 37 1029.35 1499 3860 5740 126 1116.11 1501 3730 5780 130 1108.86 1502 3640 5820 129 1098.44 1504 6060 5720 57 1132.44 1505 5870 5710 55 1126.18 1506 5630 5770 54 1110.01 1509 3130 4160 60 1218.33 1510 2990 4200 55 1200.87 1512 4000 8660 69 689.89 1513 5700 6530 44 1004.43 1514 4630 7400 1 884.90 1515 6180 6540 38 1011.36 1516 6060 6450 27 1008.67 1517 4530 6480 101 1025.14 1518 4170 6070 94 1055.80 1519 4150 6010 104 1072.57 1520 3690 6180 87 1012.80 1521 3570 6300 81 985.64 1522 3440 6360 93 983.44 1523 3340 6220 113 1016.32 1524 4580 6430 96 1028.65 1525 4590 6480 109 1035.51 1527 4750 6620 102 1016.88 1528 4770 6830 86 974.75 1529 4730 6270 100 1059.19 1530 5370 5680 41 1100.12 1531 6330 6270 34 1046.22 1532 6330 6230 50 1067.23 1533 6340 6170 48 1073.24 1534 6390 6140 44 1074.45 1535 6370 6110 44 1077.79 1536 6410 6090 49 1086.36 1537 6490 5940 40 1098.79 1538 6520 5930 43 1103.80 1539 5970 6085 34 1060.02 1540 5910 6100 32 1054.34 1541 2110 6210 64 901.07 1542 1920 6260 84 902.89 1543 1930 6330 12 882.59 1544 2030 6150 78 917.85 1545 1210 6240 71 846.77 1546 3090 6840 86 896.86 1547 3190 6880 90 900.86 1548 3630 7170 105 900.28 1549 3680 7200 105 898.81 1552 4790 7420 64 877.72 1553 4630 7500 74 871.03 Table 3.—Continued. Locality 1596 1598 1599 1600 1601 1603 1604 1605 1607 1608 1609 1610 1612 1613 1614 1615 1616 1617 1620 1621 1622 1623 1624 1625 1626 1628 1629 ay 5460 5470 4720 5140 4990 5960 5250 6020 6370 4440 4390 4270 1420 3820 1820 1490 3260 1250 4450 1390 3280 3430 3200 4440 1390 2990 2450 3110 6160 6160 5950 3690 3550 3250 1370 3440 3390 6580 6610 3950 5300 5700 5880 4910 5360 6440 5700 1520 1170 4160 4040 4260 4680 1720 3910 920 170 2580 4440 2660 4820 BULLETIN 367 xX Z: Vb 7540 34 856.65 7780 46 837.98 7370 68 885.39 7730 57 843.91 8340 86 788.62 5930 33 1078.70 6150 42 1036.43 6145 30 1049.78 6230 30 1048.45 7320 84 896.39 7400 83 883.01 7320 82 887.23 7120 84 837.98 6060 98 885.39 4910 45 843.91 4740 50 1037.68 4960 76 1137.86 4595 45 1035.54 6225 95 1048.74 4720 46 1029.74 4880 91 1164.05 7090 91 886.94 7310 92 847.98 11090 17 344.39 4795 42 1016.12 4480 93 1202.49 4490 56 1134.66 4630 52 1148.82 6130 29 1054.69 6140 29 1053.40 6110 32 1054.23 6260 81 996.55 6380 87 980.31 6560 77 932.26 6080 94 900.86 6050 107 1037.25 5900 1 1058.05 5660 44 1141.05 5590 53) 1159.72 6980 94 928.79 7470 43 869.16 7430 28 872.65 7250 36 909.29 7050 76 941.86 7310 39 887.86 6740 48 1002.42 5770 50 1108.26 4820 28 1007.51 7470 44 658.88 9850 22 497.11 6610 96 982.49 7490 79 861.93 8650 41 692.18 7720 53 671.61 6910 100 941.94 5940 39 833.81 6840 68 692.14 SOLO 56 688.70 8810 42 662.83 7720 40 714.67 5650 124 1166.34 Table 3.—Continued. Locality Y x Z Vie 1630 5630 8910 73 724.43 1631 2500 5780 61 976.33 1679 3440 8150 53 713.23 1690 680 5520 51 882.85 1694 3300 5040 72 1125.62 1695 2260 5770 58 960.73 1697 3440 8150 53 713.23 1700 4830 5660 125 1166.43 1703 4780 6850 85 CANESY/ 1705 2020 5120 60 1032.05 1706 4050 6420 96 1007.41 1707 4020 6690 92 967.32 1708 3920 6120 100 1044.14 1709 1270 4600 46 1037.23 1710 1150 4620 48 1028.56 1711 2840 5850 130 1054.67 1712 5780 6130 34 1048.52 1713 1890 5230 73 1022.79 1714 1980 5230 73 1028.33 1716 6250 6140 39 1065.78 1717 6230 6130 38 1065.53 1718 5930 6110 32 1053.64 1719 1700 4760 35 1033.73 1720 2240 4720 35 1071.97 1721 6240 7380 17 883.99 1722 1860 5440 137 1057.35 1723 5850 6090 35 1056.80 1725 5600 4970 161 1318.19 1726 4920 4970 162 1295.41 1727 4870 4970 163 1294.51 1728 4800 5340 159 1240.21 1729 5210 7260 41 891.07 1758 1690, 4785 26 1020.95 a distance of | km. Plotting the stratigraphic data in respect to the Projection Plane, which is by definition a plane, eliminates any possibility of compromising faunal range as a consequence of surface relief along a physical datum (Text-fig. 7). By using Projection Plane techniques it is possible to merge both spatial and stratigraphic components of paleontologic data into two-dimensional figures (ZnY and ZnX projections). The ability to retain the spatial component within a data set has the potential to pro- vide insights into paleontologic or stratigraphic rela- tionships that are obscured by conventional single-di- mensional graphical presentations of biostratigraphic data. Text-figure 8 presents the relative stratigraphic location of 327 Maastrichtian and Danian fossil oc- currences located over approximately 70 km? of the southern two-thirds of Seymour Island. Geographic and stratigraphic locations of Maastrichtian and Dan- ian localities are listed in Table 3, and individual oc- currences and abundances in Tables 4 and 5. Table 4.—Danian locality/species occurrence registry. Locality Meters 9 447 477 496 497 1167.94 1058.45 1179.42 1369.31 EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. Table 4.—Continued. No. speci- Species mens Australoneilo gracilis 7 Conotomaria sp. A 1 Conotomaria sp. C 3 Coral 1 Crinoids (numerous) Cucullaea ellioti 25 Echinoid spines 11 Lahillia huberi 10 Lahillia larseni l Levifusus woolfei n. sp. 21 Marwickia woodburnei 45 Nucula (Leionucula) hunickeni 1 Nucula (Leionucula) suboblonga 1 Probuccinum palaiocostatum n. sp. 1 Seymourosphaera bulloides 27 Seymourosphaera depressa 2) Strepsidura polaris 1 783 Struthiochenopus hurleyi n. sp. 104 Sycostoma pyrinota n. sp. 1 1104 Vanikoropsis arktowskiana 37 Zygomelon apheles n. sp. 3 Total 303 Brachiopod 17 Lahillia larseni 20 Nucula (Leionucula) suboblonga 1 Struthiochenopus hurleyi n. sp. 10 Acmea submesidia n. sp. 1 Cucullaea ellioti 6 Total 55 Cucullaea ellioti 3 Lahilla larsensi 15 Total 18 Cosmasyrinix antarctigera Nn. sp. 1 Cucullaea ellioti | 1105 Lahillia huberi 4 Levifusus woolfei n. sp. l Seymourosphaera elevata 1 Vanikoropsis arktowskiana 6 1161 Total 14 Antarctodarwinella austerocallosa n. sp. | Australoneilo gracilis 9 Cucullaea ellioti 3 Levifusus woolfei n. sp. 1 Mesalia virginiae n. sp. 1 Nucula (Leionucula) hunickeni 18 Pinna freneixae 1 1119 Scaphopod 4 Serrifusus binodosum n. sp. 3 Struthiochenopus hurleyi n. sp. 8 Taioma sobrali n. sp. 15 Total 64 Cladocera antarctica 1 Cucullaea ellioti 1 Lahillia huberi 2 Total 4 1130 Australoneilo casei 1 Conotomaria sp. C l Locality Meters 1072.17 1375.46 1369.29 1050.70 1095.70 1094.66 Species 57 Cucullaea ellioti Lahillia huberi Lahillia larseni Marshallaria variegata n. sp. Marwickia woodburnei Mesalia virginiae n. sp. Nucula (Leionucula) hunickeni “Paleopsephaea” nodoprosta n. sp. Pinna freneixae Probuccinum palaiocostatum n. sp. Saxolucina antarctipleura n. sp. Serrifusus binodosum n. sp. Seymourosphaera bulloides Struthiochenopus hurleyi n. sp. Zygomelon apheles n. sp. Total Struthiochenopus hurleyi n. sp. Total Australoneilo gracilis Conotomaria sp. C “Heterotrema™ sp. Marshallaria variegata n. sp. Mesalia virginiae n. sp. Nucula (Leionucula) hunickeni “Paleopsephaea” nodoprosta n. sp. Pyropsis australis n. sp. Scaphopod Serrifusus binodosum n. sp. Seymourosphaera depressa Struthiochenopus hurleyi n. sp. Taioma sobrali n. sp. Zygomelon apheles n. sp. Total Conotomaria sp. A Saxolucina antarctipleura n. sp. Taioma sobrali n. sp. Total Conotomaria sp. C Cucullaea ellioti Lahillia larseni Marwickia woodburnei Nucula (Leionucula) suboblonga Panopea clausa Saxolucina antarctipleura n. sp. Struthiochenopus hurleyi n. sp. Total Cucullaea ellioti Lahillia larseni Marshallaria variegata n. sp. Nucula (Leionucula) suboblonga Seymourosphaera bulloides Seymourosphaera elevata Struthiochenopus hurleyi n. sp. Acesta webbi Total Cucullaea ellioti Lahillia larseni Marwickia woodburnei FNeKENK OOK ww eS We NR KS ee 144 ww Table 4.—Continued. BULLETIN 367 Table 4.—Continued. Locality Meters Species Locality Meters Species 1131 1133 1134 1135 1137 1138 1139 1065.89 1087.34 1083.14 1091.90 1125.70 1107.16 1145.11 Nucula (Leionucula) suboblonga Taioma sobrali n. sp. Total Acmea submesidia n. sp. Cucullaea ellioti Lahillia larseni Marwickia woodburnei Nucula (Leionucula) suboblonga Ostrea sp. Saxolucina antarctipleura n. sp. Struthiochenopus hurleyi n. sp. Total Lahillia larseni Total Acesta webbi Coral Lahillia larseni Marwickia woodburnei Nucula (Leionucula) suboblonga Pinna freneixae Seymourosphaera bulloides Struthiochenopus hurleyi n. sp. Vanikoropsis arktowskiana Total Acesta webbi Cucullaea ellioti Lahillia larseni Marwickia woodburnet Nucula (Leionucula) suboblonga Seymourosphaera bulloides Seymourosphaera elevata Struthiochenopus hurleyi n. sp. Total Crinoids Cucullaea ellioti Lahillia huberi Marwickia woodburnei Nucula (Leionucula) suboblonga Pinna freneixae Seymourosphaera bulloides Seymourosphaera elevata Struthiochenopus hurleyi n. sp. Wood Total Australoneilo gracilis Marwickia woodburnet Saxolucina antarctipleura n. sp. Struthiochenopus hurleyi n. sp. Total Australoneilo gracilis Marwickia woodburnei Nucula (Leionucula) suboblonga Periploma? n. sp. Serrifusus binodosum n. sp. Total Acesta webbi Marwickia woodburnei to ive) FPNNNKK Oe Wwe NNO = WreNWNMN Por 1148 1189 to 11192 1430 i) ee) 1431 1432 1433 1434 1215.89 1070.85 1124.00 1098.20 1144.26 1110.44 1174.05 1165.61 Mesalia virginiae n. sp. Pinna freneixae Seymourosphera subglobosa Total Lahillia huberi Marwickia woodburnei Nucula (Leionucula) suboblonga Seymourosphaera elevata Struthiochenopus hurleyi n. sp. Total Cucullaea ellioti Marwickia woodburnet Nucula (Leionucula) suboblonga Seymourosphaera elevata Struthiochenopus hurleyi n. sp. Total Cucullaea ellioti Lahillia huberi Zygomelon apheles n. sp. Total Cucullaea ellioti Lahillia larseni Nucula (Leionucula) suboblonga Saxolucina antarctipleura n. sp. Seymourosphaera bulloides Seymourosphaera elevata Struthiochenopus hurleyi n. sp. Vanikoropsis arktowskiana Total Antarctiranella tessela n. gen. n. sp. Colus delrioae n. sp. Crinoids Cucullaea ellioti Lahillia larseni Marshallaria variegata n. sp. Nucula (Leionucula) suboblonga Serrifusus binodosum n. sp. Seymourosphaera bulloides Struthiochenopus hurleyi n. sp. Taioma sobrali n. sp. Vanikoropsis arktowskiana Zygomelon apheles n. sp. Total Marwickia woodburnet Nucula (Leionucula) suboblonga Seymourosphaera elevata Vanikoropsis arktowskiana Total Seymourosphaera elevata Struthiochenopus hurleyi n. sp. Total Antarctodarwinella austerocallosa n. sp. Australoneilo gracilis Cucullaea ellioti Echinoid spines Lahillia larseni Levifusus woolfei n. sp. No. speci- mens NNAWON Fe eBPNNN KK KW —- Ww SNe Nr WN to i) 31 80 17 16 an Table 4.—Continued. Locality Meters 1435 1442 1456 1467 1473 1483 1504 1505 1506 1510 1165.45 1140.34 1110.49 1125.13 1116.11 1108.86 1098.44 1132.44 1126.18 1110.01 1200.87 EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL ef al. 59 Table 4.—Continued. No. No. speci- speci- Species mens Locality Meters Species mens Marwickia woodburnei 7 Lahillia larseni 1 Probuccinum palaiocostatum n. sp. 1 Marwickia woodburnei 1 Seymourosphaera bulloides 11 Nucula (Leionucula) suboblonga 13 Seymourosphaera depressa 1 Struthiochenopus hurleyi n. sp. =) Struthiochenopus hurleyi n. sp. 10 Vanikoropsis arktowskiana 1 Vanikoropsis arktowskiana 19 Total pe) Total 65 1519 1072.57 Amauropsis notoleptos n. sp. 1 Cucullaea ellioti 2 Cosmasyrinix antarctigera Nn. sp. 1 Lahillia larseni 1 Cylichnania cf. C. impar 1 Levifusus woolfei n. sp. 3 Euspira antarctidia n. sp. 1 Marwickia woodburnei 2 Jupiteria? sp. 1 Seymourosphera subglobosa 3 Lahillia larseni 2 Struthiochenopus hurleyi n. sp. 3 Ledina? n. sp. 1 Total 14 Melanella seymourensis n. sp. 1 Struthiochenopus hurleyi n. sp. 1 Nuc¢ula (Leionucula) hunickeni 4 Zygomelon apheles n. sp. l Nucula (Leionucula) suboblonga | Total 2 Periploma? n. sp. 1 Struthiochenopus hurleyi n. sp. l Diautocheue pus hurleyi n. sp. 2 5 Thyasira austrosulca n. sp. 1 Total 1 ast , Total 21 Marwickia woodburnei 9 1529 1059.19 Il Hioti 10 Nucula (Leionucula) suboblonga 1 a aa Cucu eG e fou x : ae % ; Lahillia larseni 9) Saxolucina antarctipleura n. sp. 14 ase d So I es z 5 Marwickia woodburnei 4 Struthiochenopus hurleyi n. sp. 2, é Total 6 Nucula (Leionucula) suboblonga 3 MAYA aren | meer hurleyi n. sp. Q) a Nucula (Leionucula) suboblonga 1 le =e Seymourosphera subglobosa l 1530 1100.12 Lahillia larseni 1 Total 3 Marwickia woodburnei 2 Cladocera antarctica 100 Wes : Ostrea sp. l 1531 1052.66 Amauropsis notoleptos n. sp. 1 Total 101 Cucullaea ellioti 4 Peri 9 Lahillia larseni 2 eriploma? n. sp. 1 aa Ss : Marwickia woodburnei 3 Total 1 ; pe ; Nucula (Leionucula) suboblonga 4 Lahillia larseni 3 oe miete x5 Total 3 truthiochenopus hurleyi n. sp. 2 ‘ ; Total 16 Struthiochenopus hurleyi n. sp. 1 em , . 1532 1067.23 Lahillia larseni 2 Total 1 ae : ee : - Marwickia woodburnei 2 Marwickia Mi oodburmet iS Struthiochenopus hurleyi n. sp. 2 NEG (Leionucula) suborlonEg 2 Total 6 SUE OIOT ELD ASIANS BSD, 3 1533 1046.22 Marwickia woodburnei 1 lots t Nucula (Leionucula) suboblonga 4 Marwickia woodburnei 1 Wood 1 Total 1 Total 6 Levifusus woolfei n. sp. I 1534 1074.45 Acmea submesidia n. sp. 1 Nucula (Leionucula) hunickeni 1 Cucullaea ellioti i Nucula (Leionucula) suboblonga 2 Marwickia woodburnei 4 Struthiochenopus hurleyi n. sp. 3 Nucula (Letonucula) hunickeni 1 Vanikoropsis arktowskiana 3 Nucula (Leionucula) suboblonga 2 Total 10 Struthiochenopus hurleyi n. sp. 6 Crinoids Total 15 Nucula (Leionucula) suboblonga i 1535 1077.79 Bittium (Zebittium) brooksi n. sp. 50 Seymourosphaera bulloides 1 Colus delrioae n. sp. 1 Seymourosphaera elevata 1 Conotomaria sp. A 1 Struthiochenopus hurleyt n. sp. ! Cosmasyrinix antarctigera Nn. sp. 1 Vanikoropsis arktowskiana l Euspira antarctidia n. sp. 2 Total 5 Melanella seymourensis n. sp. 3 Cucullaea ellioti 1 60 Table 4.—Continued. Locality Meters 1536 1537 1538 1589 1591 1599 1601 1086.36 1098.79 1103.80 1137.86 1164.05 1202.49 1134.66 1148.82 1053.39 1058.05 1159572 Species BULLETIN 367 No. Table 4.—Continued. speci- mens Locality Meters Species Nucula (Leionucula) suboblonga Nucula sp. Saxolucina antarctipleura n. sp. Struthiochenopus hurleyi n. sp. Total Cucullaea ellioti Marwickia woodburnet Nucula (Leionucula) suboblonga Struthiochenopus hurleyi n. sp. Total Bittium (Zebittium) brooksi n. sp. Cucullaea ellioti Lahillia larseni Marwickia woodburnei Nucula (Leionucula) suboblonga Struthiochenopus hurleyi n. sp. Total Cylichnania cf. C. impar Euspira antarctidia n. sp. Jupiteria? sp. Lahillia larseni Levifusus woolfei n. sp. Marwickia woodburnei Periploma? n. sp. Seymourosphaera bulloides Struthiochenopus hurleyi n. sp. Total Bryozoa Struthiochenopus hurleyi n. sp. Wood Total Bittium paleonotum n. sp. Total Marwickia woodburnet Nucula (Leionucula) suboblonga Paleopsephaea? nodoprosta n. sp. Seymourosphaera elevata Total Levifusus woolfei n. sp. Struthiochenopus hurleyi n. sp. Total Marwickia woodburnei Nuculana antarctirostrata n. sp. Pseudofax? paucus n. sp. Seymourosphaera bulloides Struthiochenopus hurleyi n. sp. Vanikoropsis arktowskiana Total Mesalia virginiae n. sp. Seymourtula antarctica Total Wood Total Cucullaea ellioti Seymourosphaera bulloides Struthiochenopus hurleyi n. sp. Vanikoropsis arktowskiana 1 1 l ] NON 10 Ae NY E50) OWE Qe ee ee 10 why esp Zygomelon apheles n. sp. Total 1700 1166.43 Crinoids Seymourosphaera bulloides Struthiochenopus hurleyi n. sp. Total 1715 Mesalia virginiae n. sp. Total 1716 1065.78 Turritella (Haustator?) parisi n. sp. Total 10 10 No. speci- mens 1 25 1 4 5 1 1 1 1 EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. Table 5.—Danian species occurrence registry. Taxon Acesta webbi Total Acmea submesidia n. sp. Total Amauropsis notoleptos n. sp. Total Antarctodarwinella austerocallosa n. sp. Total Antarctiranella tessela n. gen. n. sp. Total Australoneilo casei Total Australoneilo gracilis Total Bittium (Bittium?) paleonotum n. sp. Total Bittium (Zebittium) brooksi n. sp. Total Colus delrioae n. sp. Total Conotomaria sp. A Total Conotomaria sp. B Total Conotomaria sp. C Total Tholitoma (Cosmasyrinix) antarctigera n. sp. Total Cucullaea ellioti Locality No. specimens 1119 1134 1135 1139 (ey 7 in) No = OV eH OV ww Si — te ie) 60 ie) Ww Table 5.—Continued. Taxon Total Cylichnania cf. C. impar Total Euspira antarctidia n. sp. Total Heteroterma? n. sp. Total Jupiteria? n. sp. Total Lahillia huberi Total Lahillia larseni 61 Locality No. specimens 746 1119 1130 1131 1135 1136 1161 1189 1192 1430 1431 1434 1435 1510 1529 1531 1534 1536 1537 1601 1519 1538 1519 1535 1538 1104 1519 1538 38 Ne KBP HOOK NK WORN Ke Ne = yt wWwhoft KH wWNONAKRO to SiS WRF eB Oe OWOON HK i) 41 Table 5.—Continued. Taxon Total Ledina? sp. Total Levifusus woolfei n. sp. Total Marshallaria variegata n. sp. Total Marwickia woodburnet Total Melanella seymourensis n. sp. BULLETIN 367 Locality 1508 1519 1529 1530 1531 1532 1538 1537 1519 Table 5.—Continued. No. specimens SBE ePnVnnrorr th WN FUND wre nn NONNAINY OK KH KH WO wn kee MmArAfe Wo ta 110 Taxon Locality No. specimens Total Mesalia virginiae n. sp. Total Mitra (Eumitra?) antarctmella n. sp. Total Nucula (Leionucula) hunickenti Total Nucula (Leionucula) suboblonga Total Nucula sp. Total Nuculana antarctirostrata n. sp. Total 1535 497 746 1104 1139 1548 1591 1715 yy ae ARKH NDADN OWNN WNe Re Ne wp nAnfkeEK De NFHLOO Ne tN EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL ef al. Table 5.—Continued. Taxon Locality No. specimens Ostrea sp. Total Paleopsephaea? nodoprosta n. sp. Total Panopea clausa Total Periploma sp. Total Pinna freneixae Total Probuccinum palaiocostatum n. sp. Total Pseudofax? paucus n. sp. Total Pyropsis? australis n. sp. Total Saxolucina antarctipleura n. sp. Total Serrifusus binodosum n. sp. Total Seymourosphaera bulloides 1131 1483 746 1104 1586 1701 1161 1138 1519 1484 1538 497 746 1132 1134 1136 1139 1 1 yh Wt] Oy = | Oo — Yl fel — tp = N = oO er SeSuto: ie! aes in) ios) WRNNON Nee ww to Nm tN es) ne 40 Table 5.—Continued. Taxon Locality No. specimens Total Seymourosphaera depressa Total Seymourosphaera elevata Total Seymourosphera subglobosa Total Seymourtula antarctica Total Strepsidura? polaris n. sp. Total Struthiochenopus hurleyi n. sp. 1432 1434 1506 1538 1589 1601 1694 1700 ys Seas) N= rey — Ve SOS pono a ww Woh wo WN hm Ww WoO Nsthknvne a Or Ke NRF Kw 40 64 Table 5.—Continued. Taxon Total Sycostoma pyrinota 0. sp. Total Taioma sobrali n. sp. Total Thyasira austrosulca n. sp. Total Turritella (Haustator?) parist Total Vanikoropsis arktowskiana Locality BULLETIN 367 Table 5.—Continued. No. specimens 1502 1503 1505 1506 1507 1508 1510 1519 1529 1531 1532 1534 1535 1536 1537 1538 1548 1574 S77, 1587 1589 1601 1697 1698 1699 1700 9 261 496 1134 1205 1335 1414 1430 1431 1432 1434 1505 1506 1507 1508 1510 1548 1589 1596 1601 1698 Nn ANNUON ore N= WN freee NN w on) wee KE NKHNnNNK WOK Ke KEK We Kae 19 Taxon Locality No. specimens 1700 4 Total 62 Zygomelon apheles n. sp. 9 3 746 5 1104 1 1192 1 1431 1 1442 I 1601 l Total 13 ACKNOWLEDGEMENTS We would like to thank C.E. Rinaldi, R. del Valle and E. Olivero, Instituto Antarctico Argentino for their support of our fieldwork on Seymour Island, and the many individuals who collected specimens described in this investigation. W. Allmon and N. Dutro, Pale- ontological Research Institution, edited and greatly im- proved the manuscript for publication. Many col- leagues assisted us throughout the duration of this long-term study; they are A. Edwards and B. Pump, James Cook University, Townsville, Australia; D. Gelt and P. Vickers-Rich, Monash University; C. del Rio and H. Camacho, Buenos Aires, Argentina; M. Griffin, La Plata, Argentina; K. McNamara, Western Austra- lian Museum, Perth; W. Ponder and I. Loch, Australian Museum, Sydney; A. Beu, Institute of Geological and Nuclear Sciences, Lower Hutt, New Zealand; and A. Grebneff, University of Otago, Dunedin, New Zea- land. We would also like to acknowledge the support of Dr. S. Borg, Office of Polar Programs for his efforts and support of our field program. This work was sup- ported by OPP grants 94-17776 and 98-14533 to WJZ and an Australian Research Council Fellowship and grant, a James Cook University Seed grant, and a Monash University Support grant, all to JDS. EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 65 REFERENCES CITED Abbott, R.T. 1974. American Seashells. Second Edition. Van Nostrand Rein- hold Company, New York, 663 pp. Abbott, R.T., and Dance, S.P. 1983. Compendium of Seashells. New York, 248 pp. Adams, A. 1850. 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Zinsmeister, W.J., and Camacho. H.H. 1980. Late Eocene Struthiolariidae (Mollusca: Gastropoda) from Seymour Island, Antarctic Peninsula and their signifi- cance to the biogeography of early Tertiary shallow-water faunas of the Southern Hemisphere. Journal of Paleontol- ogy, vol. 54, pp. I-14. Zinsmeister, W.J., and Feldmann, R.M. 1984. Cenozoic high latitude heterochroneity of Southern Hemi- sphere marine faunas. Science, vol. 224, pp. 281-283. Zinsmeister, W.J., and Griffin, M. 1995. Late Cretaceous and Tertiary aporrhaid gastropods from the southern rim of the Pacific Ocean. Journal of Pale- ontology, vol. 69, pp. 692-702. Zinsmeister, W.J., and Macellari, C.E. 1983. Changes in the macrofossil faunas at the end of the Cre- taceous on Seymour Island, Antarctic Peninsula. Antarctic Journal of the United States of America, vol. 18, no. 4, pp. 68-69. 1988. Bivalvia (Mollusca) from Seymour Island, Antarctic Pen- insula. Jn R.M. Feldmann and M.O. Woodburne, eds., Ge- ology and Paleontology of Seymour Island, Antarctic Peninsula. Geological Society of America Memoir 169, pp. 253-284. Zinsmeister, W.J., Woodburne, M.O., and Elliot, D.H. 1989. Latest Cretaceous/earliest Tertiary transition on Seymour Island, Antarctica. Journal of Paleontology, vol. 63, pp. 731-738. EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL ef al. PLATES 74 Figure io) Los to 1-4, 6, 395 20, 9) 8. 10. SeJUpiteria? SPECIES! <5! 4p2). iste. asaya eas tee Soe tans ags carota ta) Sh sesy toe eas eeu eas eRe gens 3) (e/ Gre the ncriealke, «Nee onan hetero a i BULLETIN 367 EXPLANATION OF PLATE | Page Nucula (letonucula).suboblonga: (Wilckemns,, 1907) oar. ecte = chien aie tee eustubene eedapeme ne clasiieienr eres Oy LO} 12. 13; 31-33; 57,4617 '84 5,853.6 Antarctodarwinella ellioti Zinsmeister, 1976 ........ 13531, 32 Antarctodarwinella nordenskjoldi (Wilckens, 1911) .......- 13 antarctonodosum, Bittiumy 20. b 226.5 ceva so es ee ae Dil API Poraminiteral Zones «oc =e ass eters reich eee ss ae mite ee 7 GpNelesA.Ly 2 OMELOM AMG SDs aslieenehsdecensus tena Mes, cliclou ay pelee nee oe ete ees 2 ode LOL 12) 475575585900! 045,92, 9310 PBT CO Te eyes us Seen dese Ea Eis, Bosch wi etehinns Ree ne tee eur 16 Arca nucleussinnaeus;, 758" sca. © tases aie eeishs ses tne 16 arktowskiana Bunaticina?’ 10 222 Ghee vie eX e cle eee See 33 ArKLOWSKIANG, WANIKOFODSIS =. = ton cel creas maces eisieste al oi ans nies sca eesdteenc got mayer ote 8, 10, 12, 33, 57, 58, 59, 60, 64, 84, 85, 6 arthropods? avs. srokene! 2s ais shecke, & Sp GATROMe MERE R Orel ns Rein, oN ches ces 15 AISTQrLO a eecssteisiiet ei haanaSue wee way e atee eR Dy aeer eps hata ohh Laval ares ay 24 Astarte:.cf..A. venatorum Wilckens; 19110) 22 222. 56.+64-+: 24 auriculiferay Cucuilaed. diate teed arora eae iets eee ae 20 Austaloneilom mies. 8,9) Dil, 15), 19; 20) 57558361 742 75 ee austerocallosa, Antarctodarwinella n. sp. ......---++++++++ wk 2 dit femeus sete is gee Geeee D4 Oy LO; 12) 135 SI 33557 Ole sas oiG Australi PrOVINCe: Py iy ike sede eae eee eee eee 13, 14 australis, Pyropsis? n.'sp. ... 5, 10) 12; 37).385 S7;1630:86,.87 07, Australoneilo cultrata Darragh, 1994 ............... 19, 20 Australoneilo rosst Zinsmeister, 1984 <2)... 2s 1- eran 19 Australonelio ....... 8,,9;. 11,15, 19) 20! 57; S856 7455s Australonelio casei Zinsmeister and Macellari, 1988 ....... ENO EN ae Or AO Re 8,9) 11, 19) 205615 745 75s Australonelio gracilis (Wilkens, 1905)) vius 2s ajar steerer Bey Goats, Sah oie, EPPS ren tienes Maik TON SS 9; 11,19, 57; S861 745 75a AUSTTOGDOTTNAIS ce sepat se tere axes! Bakc.she os. si ee eee 8, 31 Austroaporrhaisilarsent 2.2.5 25 «2 or) oe geen ete 8 Austrocucullaead’ Galtewee sis 5.56 = tics tune, Stake 8 Austrocucullaea oliveroi es «2. ac02 5 5s 1 ee ee 8 AUS EOfICOPSIS! axa. syerse Bs soe SS) Se ayoeace tens Pete 42 AUSITOSDAGERG: 3 iis fied B34 5.1312 Rudy scos else Eee an RE 13 Austrosphaera glabra:Camacho; U949) 2 6 2). teen Se 43 Austrosphaera patagonica (Feruglio, 1936) ........... 43. 44 austrosulca; Dhyasiram: SPs 26). 2 558,95 11 225235593: AUStTOLOMA? (© Shae ols Me lefedh aes 6 Re aeieyrios adeno tee ea een 49 AUSTOLOMANOLIVETOL. sus ince occ suche sue tens eRe Rene 49 BalcisMedch 84s a23. a5: gas @ Gt oso ete eee oe een 36 bartrumiGylichnania cscs & acter ie ee 5) bicarinata, Taiomay se 22 ses 3 share fe ee cytes 46, 47 binodosum, Serrifusus n. sp... 5, 10 12, 42, 57, 58, 63, 90, 91, 9 Bittium «....4... 5,8, 10, Wl, 12; 13; 27, 5951605 GI s2 58355 Bittium antarctonodosum Stilwell and Zinsmeister, 1992... . 27 Bittium (Bittium?) paleonotum MasSp.2 i. a wees Savas) eee si uN eees hime mrsae etalon ne Se 5; 8, 10; 12, 27,60; 1617825835 Bittium (Zebittium) Drooksiem: Sp. ii. s + ee hana, « vateuana peta eee Wed bate aret s fe ae Dn LOP Mk 125275 28759 GONG l aS 2neSsns) Bittium (Zebittium). editum Powell, 1979)... « sccde ces = cleus 28 Bittium (Zebittium) exile (Hutton, 1873) .........---- 27528) Bittium (Zebittium) granchii Stilwell and Zinsmeister, 1992 .. 28 bloom families: oo cncy. ci ceras tees iiss eins iene eee 11 DONALYLMEUSDITG a had alete tars icie styrene fl 2ch ei eee ne 35 brachiopod (s)ievcicacnemsneusts Cae outa Net sip cauieuat Mee ae teenie 6; 75.37 brevialis; Mesalighe cts accuse cys aie 2 omer 62h Phe eee 30 brevialis;, Turritella a ousteie aie 24 wie leven © oe: = potest ope 29 brooksi;, Bittium™(Zebittium) M.vSp-. - ii: 2x. 3 haa eee wi gtr e woaayediegnrens D5 LO} W125 27; 28559 160 ROI ez eesee brychiosinus, ‘COSMASYVINX. sels eeys He esas 22 ee ee 50 bEYOZOa(S)) cp des, niece a rouse eeRePa eee orckans, we 2c een ene ae 60 bulbifonmes HUSUS ats « o.c08 a) eens. oie teh kal een eee 42 bulbiforme: SVCOStOMmG Was clove mame enh cast oe eae ee 43 bulloides, Seymourospnaergd 2.2. os ue = 3) Se ee Sea eye ss ale se Dy Oy Os 120435 445 57581 09,008 OS poo mooms Daa Retr ee eae e cog eof Gomiatiomer mae eicacr ort Spo 11 Calcareous: MaCrOflOSSlIShe < ensue ates 2) sheers) saps sores ites U Galcareousinannoplanktome ts ci tense sroreiss ete oir esi cine eee ones 7 calcareous) plankton™ jey-it 5 sicheclolens- step tats ieteeene meee nam 7 (Rignthioins Welea been 6c og ow od laos Sa ae oe cies 10, 12 casei, Australoneilo. 2 22 os ov 85.9, 1, 1920561574; 7571 GQSSTAGTIG vate o wrcsohet cs rere: cer ceca sy, ur estes eee eee 8 CaSSidaria Mirabilis! Gia coeieusta =e c-n tps) oe ss) Oe 8 Gerithivurme acct ces oe cssce age SA eR eae ee 2129 EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 85 Centhiumiextlissiuttons USS -tatene = cise os os cs Steele 27 (GerithiumimesalXdansonhy -teyevsig =i sys) 2 ce eess= seu sees) 2) ons. seat 29 GerithivmspyZimsmeister p99 Sava. eens reesei aesieden nate © Dil, Giga CNUOMITUIG 555 ool be base see ode be. 6 ooe 8, 11, 24 ARARCOTAIDS, UCHNM) oo. oncom soomeaadun aoe Udo OK 8, 47 GRUDULEIIS ISSO SLELLGT Lawn te Rep ica ites iene ese cael 31 (GUOVILGES Dhimmi hae cae ia occ oes scenes a fe oe Peete p ed Su Sa he ARSENE 8 (CHEAGR SARs, se Boke OO Lio Oro OO co Chron one tree en aie 57, 59 (Glad oGerakantarGticas Fyn sates eleaste-= eee ees eso S99) GlaUSaNRANOPea. = Meni sae eee TS. OLS 24 S753 GLUT AB a foe, ete hs ess tesaee hase terd. Sk tks RPS, Poe el tussles toes bs 46, 47 (CONWR Sree cere icaronas D5 SO} 12,385.39), 58:59) 161, 86; 8757 Colus delrioae n. sp. .... 5, 8, 10, 12, 38, 39, 58, 59, 61, 86, 87, 7 GColusmislandicus) (Gmielins 1791)) Feb act ae.s ses ee ee 38, 39 COlUuS2aTHOMBDOIdCAS aie aav ss vs ayaa eps nchencueds af Gahan ord at 39 Gominella? praecursor Wilckens; 1905 22... 525225. ews 37 (COPTIC seve: He eae RC Oicen Renee CERRO CRE Ct eee 39 CONGAVGMINUCHICE) Fake cule iia A) spotrie occ Gigs ore sates we eveeees 18 (GONGCOLY Cpe ace © faiay 5, stetsienc ogee iors: TERRE: NS aa 3), 32 Goncoihyra parasitica Wutton,, W877) = 52. ee He ee 32 CONICUPP HOS mia ehins oye s2 aystis i cteeslid, Boe, etre cane Ryeeeehi Rede aus 39 COMIGUS SPSCUGOSAX 3.5). rog ei is eres ese ees SE 40 Conotomaria ....... D500, 0 OFZ 13525557 S9NOl SON81 4 Conotomaria mailleana d’Orbigny 1842 ................ 25 Conotomaria sp. A... ... DO nl OFA 25575, 5961, 80, 8174 Gonotomarialsp) BY. 2 5446-2 5, 8, 10, 12, 25, 26, 61, 80, 81, 4 (Gonotomaria\ sp: © « veeee, eeu 5, 10, 12, 28, 29, 60, 64, 82, 83, 5 taustaton gracilis Montfort, USilOk sec. .)tavs steven ies = cen 28 NElICOLd CS SINAL Cis ors tie te ait eee Oe OR 33 heterochroneity® ss tv ceeaeneteee eee 6; 12 Mfaunalabyssater egret ua wot een eenaiee eden Cans rel tiencee Oe UNI IGIUMANOmMaAlysche ii Ph ccs lhais a es Mieankasee het eeeeioae ane Ie 7 tslandica; AMAUmOpSis ob @shaigies ebcie ess ee Os 34 ESLANAGICA INET IG, 2.245 anette: apaidl anahe ee, eis lene ened cree i 33, 34 ESIGMAIGUS RE OLUS3. Stew dra tetegcee estes saa) ae tet eM ke Shey Sh) JaAmMeSHROSSHE ASIN vex. haeme os eee, 5 hls wo saeasticas le, cacy Seem ead 13 JOAQUINIENISISS SCT TIUfUSUS: sc te ara ase amane ais epee ee nee 41, 42 JONEST ASV COSLOMGA (ass. sisud os hone cietane S¥ekeus con areas Cae ee 43 JUAUINAE GY FINCUTTUnsancgne cis fue 2 Aes we ee eee eee 36 UDILChIC aaa cree een ne 5; 9; 11, 15, 18; 195595460! 61. 745 75; Jupileria?: Spo svaaie oo chs 3, 9, TI; 18; 198 S9NGOW6i; 743755 1 RitChinitess coe cye nieces soba tel hoods (ee Vaiss Parr oa Sel ate ee 8 Raitchinitesslaurae yin = oie cciecncesicieneno cena eee eee 8 K-T boundary extinction .........5, 6, 7, 8, 11, 12, 14, 15, 51 KT IGIAucOnitee ve eiskee S caet earns cae cea nee cae eee Ten) labellatasEuspira? cn errs. stacy) | ieee een eee 85 labellatasNatiéd o3ia 5s icatic aiisyare. cheba enciren et 34 7 ah Te ae ene ae eR aE CR RC OOIA OOD EEO CO OO. o.com 0.0 0 8, -9510; 11, 15,235.24, 57, 58; 59560; Gl, 765.775, 7897 9R2s3 Eahillia flOOS: sda. ths cice® eosin scion ne. hee See 11 Lahillia huberi Zinsmeister and Macellari, 1988 ........... God (Seen Mertens BeaneneNepe es eee 9) 11, 23, 24; 57, 585/615 78597993) Lahillia larseni (Sharmen and Newton, 1897) ............. Spar yates cei 85,9) 10, 11,23, 57, 58559, 60; G1, 162576 7HEe2 Lahillia luisa Wilckens: 1OlO) | See ee cick ee ikea ene 23 larsent, Austroaporrhais) 2 onc aac wise oe cosets sitet ee 8 larsent, WE YDKiInG 0 tee Soe ree Belo cote ease 23 larsent,Lahillia: "s2rsta sce as 8, 9, 10, 11, 23, 575/58, 59; 60861 larseniana; (Perotrochus® «isch. weewn 4 oe ieee serene 8, 25 Laternulan 230 seni ache adiate he DA eiten se ee Seen eee ee 25) latgens;. Eima@ Cho Tis, 2.1. 6 ees futowsvions, 9) sue coe een eee 21 laurae, WRUCHINILES” aie een etoile o, nse de.8s eee eT 8 lautoidessMelaneliamy.miein ox a8. eet ae eee 36, 37 PQZQTUS! 3/512 Ry ae ad cnt © aerate Bye Ee em LS VCMING! wad oistaet Vee eee eee DS OF UT DS 1859 NO 25a/ Ase Ledinaxeborea'Gonrads, 1860). 22 2s sense pee ee 18 Ledina paucigradata Singleton, 1943 .........28..0.2008- 18 Ledinasmirna’ Dall, W898i was. 2 acto 0, hs sate es cre ee 18 Ledina taioma Finlay and Marwick, 1937 ............... 18 Ledina? Sp. secs ae os 2 esta Ds Oy 1, 1S, 89590162 Asa Leionucula «... 8,9, 1, 15, 16, 17, 57,.58;.59; 60; 62: 745755 Eeionucula\ poyaensis: Breneixy L958 2.2 = ai. 2 en en eee 16 levicristata, ‘\Cosmasyrinx (Tholitoma).... =. . i... & ee ee 50 Levifusus .. 5, 8, 10, 12, 13, 40, 41, 57, 58, 59, 60, 62, 90, 91, 9 Levifusus maputi Gliozzi and Malatesta, 1983 ............ 41 Eevifusus: mortonit (Wl. Lea; 1833)) 2622 << 20s Sas coe een 41 Levifusus mortoniopsis (Gabb; 1860) .......-255..-.se8 41 Levifusus quadrifunifer Darragh, 1997 «= 23.4222 a eee 41 Bevifusus.woolfer Ms :Sps i 26. a.0k cane Gc els Ol nae eee ee wise eheta hs alanis Dy Oy, LOK 125 409415575758, 59) (60! 625 90 ROI gS DINAH 8h srg telah aia. aeaiaestoy ae Poh fe aes ea) OL aa 21 Eima‘antarctica Wilckens;, 1910)" 2). <2 5 ae, 2 cae 21 Lima’ci. E.latgens Ferughio,, 1936)... asc 2 sy < shoe eee 21 loryiiePseudophyllites...21. 1p eh © = cusucse 2 aie heh renae eenene 8 louellaes Ranella cau. cloak oe oct 2 se a ayets eee 2 eee 36 Lower Glaucomite: © <0. caosienscene = © ee) e enereie olen ee enn 1 TEMGING “Fi aya 8. ce Oe BeOS Poaceae ae 83 215,22 Lucina promaucana Philippi, W887 we wise eet ete neem 22 Lucina-saxorum Wamarcks 806 nec e ee cnet 21 DEUCINGES GOUL se pons okt, ed eesce cee ee to Se ete ROR Ree en 8 luisa; SEARING tgoks, J ntie sagt Rises mache A yoasoe eee ree 23 TEV TOLAUS 9's Saaqle a Safes, Reick fo {eus0sue vee ioon a) eer aasl seen ee eee 15 mailleana; \EONOLOMAL Gre re, ere.c) te) ene cence cen en ee 25 mailleana: Pleurotomaria’ =< s/2e..2i Nate 2 =): Sle ae ae 25 Malletia’ > a. \Sscn ann Oops atets Sener ante ol Teen oR 19 Malletia: sracilis Wilekemns; W905 a. 2) esc de secs actuarial 19 MGOPFILES snd AR eee eves NS ene 87S bya © RENO ee Ree 8 Maorites densicosignis). sic = 2a cicne ma eee ee aie ee 8 MATLATIACEA: \COTDUIG LS cc Jalencie teitsiel sthe,etel anes stleiset/-ee elev sede 24 Marie Byrd Land! s.c.2 7. 5 © citys lesou sp ucke ome, cite onerel hel een 14 INATINE SEPtilES) ax sa. «Gos es acee siege aus uct) ae ganeeasl neuen em Cae 7 Marshallaria ...... 5, 10, 12, 48, 49, 50, 57, 58, 62, 92, 93, 10 Marshallaria multicincta (Marshall, 1917) ........... 48, 49 EARLY PALEOCENE MOLLUSKS OF ANTARCTICA: STILWELL et al. 87 Marshallaria tumefacta Darragh, 1997 ................. 49 WO AANT TO WT BAG Coy as opt ese Oc oid oe GerOroe: 6 ey rome eres LOS 2 A8e 4 ON SON 57558562592), 93. 10 Marwickia ....... SOI WS; 245, 575,58; 59; 60; 62, 785 79:3: Marwickia woodburnei Zinsmeister and Macellari, 1988 oo, edieg afoge At Ane Ren Ee SH OF W124, 57.58, 59: 605162), 78;, 795.3 AE QUD IDI GOGAT Choon Soa bene soe uonnadss ated: 8 TLELEV.CVISUS PAI LUT OD SUSI riley eich eli Velie cas eiieeo eeseevia a eiceeene chee 34 Melanella eaaya as case LOR Me 1255365317095 (625 SOs. 7 Melanelladujresner Bowdichy W822, 7... 02. eee ne ee 36 Melanella lautoides Finlay and Marwick, 1937 ........ 36, 37 Melanella pontilis Maxwell, 1992 ................. 36, 37 WMelanellags €yMOourensisneesp 4 sea tenc iain +2 tne ele oe 2 here Go SONA iD kok Prose eee D5 1012536; -37,,.59;162,86; 875.7 LILES ys © CTELMLLLITD, axon spr vranrah shes Pages Says ave aca ES esau hey wris ie Hie 29 Mesaliay yc.) D318;) LO; 125 1135,29530)57;5.58; 60; 162, 82,835 5 Mesaliaibrevialis,(Wamarck. 911822) 6.2) 20e-0eks eos eae ede es oe 30 IQS EI WABI? NSO a Aavconageds aaedqsaeogdn a aneos e 5 noua hole crea area DOs l2) 29) 30) 55059; 6062, 82.) 83:5 WVICLACTENUS meen Woke oie hol cy set cis Ue ON eRe CU nS cia Cosine Gites 1S OIA (CUNT eS ofan a ooo a aol oo aco o.c eo one 8 VIET Ieee eee onan, sek deye aeiel Os 2s AI ASS 625/92) 93-110 Mitraalokiza;Venison=Woods, W880) 2 sss Face se 47 Mitra (Ewmitra) antarctmella n. sp. 5, 12, 47, 48, 62, 92, 93, 10 Mitra (Eumitra) sadleri Stilwell and Zinsmeister, 1992. ..... 48 Mitra (Ewnitra) waitematiaensis (Powell and Bartrum, 1929) 48 THULOE CWA CINGCON Nes seston uehcine Wawasan sy sada hceesu bares syeceiesl ees 26 TILLER CVO LULA vratcc, Ses Sp me etic be hens-y elem ec mnee spon A octet coins aoe 47 VIO GIOLU Stern wesc sie ey ee Sees As irse sis eeey ome so ced (iS tens 8 WMO GLOLUSHPONLOLOGENSISs a hammer necney ence seer ee ee eee): 8 ROCHA CONES eed ao eiod co 5 Hales cee ae eens 50 MOTION ELCVEFUSUS: aon .ci= aha Poi edisv el ote © io ees ht ous eowe 41 IMLOTLONLODSIS: SELVIFUSUS i a= fahroecch =| eof asters) suc) Fs) ese =) eh eiie cae re ole 41 MULLING IVIGY SNAIAT LG) tyepe oteiel 1 cient neers ere: 48, 49 IVIL OX are open cg eey atr= ooh eA wy clash autihiawtectsh, erienane: Bueaenelie: eveseniecs eas 27 Murexsreticulatus (Dai@osta, 1778)! 2. o- . 3. eee se 27 Murex turgidus)(Solander, 17/66)) «22... «a+ seer ee = 44 MUIADILIS) PGLCOPSEPNAEG: iat styles 4 2 2s es a ee 45 VA ON PMA CNM R Neots en st oes, ap aers sav eyalanise Ht criere Mereey seeeereb eis cts. 24 Mya ely CuneriSuBOIDs MiB" a cies sire ciens ee cieeere steve deve 24 NEXSTROGE oa teew i os CIN ole OO OE ob cae he oes 39 IN CLEC OD Secs yey oh sic se Ss Poo Soh oE Dato 5) 6 igus Beker ies a LSHEUN sacle? & Some 33) Natica’ glaucinoides J..Sowerby, 1892 2.2.25. 5.22555 34, 35 WNatica, helicordes) Johnston, el 83) ji-nse) oneness) seeds ene ee) anes 33 Waticarlabellataswamancks TSO4 07) cre eievsnsiaeua tas sascha 34 Neilo (Australoneilo) gracilis (Wilckens, 1905) ........... 19 INI TIQD sta! coc eh gee act ON Roe TEER oR ee Ra eae ree ae 19 IN EKEWESROSSD st yirretcedahituey ies aiityloh se ena onepens: Ghastes PIERSIMD Wed ie TAO 8 INCODUCGCIIUN Decay he aeedere Sp ere Hct outset alee eas epee Mee uae 41 Neobuccinum ienerum smith, W907 5 i sens aces ose 2 41 INQATIEE 5 Gm eA Ean OBR reais & Secure GD a eet Gea tee eae 33 NeritanislandicasGmeliney li. Oilin ayets ate eee teens) = eaceeh cic ae 33, 34 MUSErLEMSISs MMUTTILELIQ|(HQUSTAION)) asce = seis c ees «os 29 MOGOPTOStG, we AleopsepNacamM) Sp: Ga) = (erste tees: eee eae) sie ep. = seh ba. Dlotalelagt ce cree ere cae eye 5, 10, 12, 45, 46, 57, 60, 63, 90, 91, 9 nNousiphonatewntaumale -wepeps leat sha enetensneve tases | eeeeebaues ae eis 11 nordenskjoldi, Antarctodarwinella ........::i5.252+5+. 13 MOT ACRSKIOIALWNoOrdenskjOldia® ~ he sac. 52 As Ge ee 8 MOTACTISKJOLA LG RCiISSOPLENG) ey -pete yale s-iepeielnietehenceis: ene ete 30 nordenskjoldi, Struthiochenopus ............-5..-+4+ 3053I IN OTE EMSK] OLA Cg Me ga ne: a Nhs AS i Ibn ek ea ss Oks 8 Nordenskjoldiainordenskjoldi . 0s mnt it eS 22 cote chcieis 20 55 10}-12, 135.37; 38; 5i7,635186; 875. 7 Pyropsis zelandicay (Marshall, U9INs7)) a =, cespeciee) sneered, x, =uete = ote 37 Pyropsis? australis n. sp. >} LOY 12537) 38557103, 80.05 7 Pyropsis? gabbi (Stanton, 1896) [Heteroterma] ........... 37 QUAAKIFUNICTALGVLLISUS -crrareie euieueuayc ae nein. temo aees 41 IR GMO ee ene tie te Pee Es ke Gee EN EE ee ae Ge 36 Ranellatlouellae Beuy VOSS a. 2. = a ensle onae mae eusiee eis ete seeeenes 36 LSS UY FL Cea hath (cg EERIE eR TR cs te ere ER cry he en ics 8; 15 FEZING, ESCLACVIIFISONIAY oe aie vache canis cee sie ee elena aio ee 8 reticulats! Milrex e205 srtey ahs ests teud w.< arene sie) Senne Di. FLOMDOLCEGN COLUS?, fae as sunray at 02) apedn ayaa ah ee een 39 THOMMDOIAEGMUASCLOIATIO % a ota ews ae ee. ¢ eucme ee Rae ae 39 TOSSIANG WAIMAULLODSIS sates suate bie anepertheae tense Renee monekalene aot 33 TOSSLGNG: ‘SOLEMYA) (roses tashh-aesitalaciaas Shenae Net Nee Res ie meee oe 8 Rostellaria chubutensis von Ihering, 1903 .............-. 31 Rostellaria patagonensis von Thering, 1903 .............. 31 sadleri; MULT ay (EUmnitr@) sctach a ees ae ae aA eee neve ents 48 Sassia kanabensis, (Stanton; 11893) ci. csees we enon Sone setae 36 Saxolucina’; .. 5;.8;, 9; Vil, 15,2122. 57. 58; 59)..60)163.°78. 7953 Saxolueina antarctipleura n: Sp. 22 sae 25 6 oe ele ane eee we cies 2s D5 Oo Os UIE 21 2250575 58;, 59100103 1 Osu oees Saxolucina sharmant Wailckens; VOU Ves se ee to eee 22 SAXOTUM EUCING® (x fecece sa a fe essa 2 sees) | eee ee sans) He 21 SGXOSULEMSIS, -EUSDITG, "aars)e) = es elise, ie eee 35 Scaphopod(s)) (Wrctel. ccuse esac tare vsuetionctehaoyeesyoulerahnemenel hoes 6557 SCOME, TUCING (ooo reece ser ayn Hs oom 8d foes cartay atlas. oe Se ea 8 S€a-surbaGe) temperatinesiy-e-pces) ens fis) ce) aed sl erie eee eee 6 SCIECHVETEXCIMGHOM cae oy a: sania ter oie) Sheree stole) et een eae eee 9 SENTICOSUS PROS: 3052 ayacc Sak abate suas ie see tae eee 39 Serrifusus .. «25... 5; WO} 125.13, 41.42.57. 58635.:89 59089 Serrifusus binodosum n. sp... 5, 10, 12, 42, 57, 58, 63, 90, 91, 9 Serrifusus dakotensis Meek and Hayden, 1856 ........ 41, 42 Serrifusus goniophorus' Meek, 1876 22.502. a2 s- 205 4c 42 Serrifusus joaquinensis Anderson, 1958 ............. 41, 42 seymourensis: ANG AUdryCeEras. 3 veneer omen eee ee een es Oe OSL 298 BON OTs D800; (0220210945 VOHEI Game Gemiaciay styshn. ay chsh cess sy a) ayfsheite Yokshsyu, apeicavayscah oa iay eal eats 47 Vo lutanmitragleinnacuss WS Sierra cies aicuetcsl ees) cic. lve 47 wattematiaensis; (Mitra (EUMIra) J. ss ee eos ee te 48 WEDDUWACESTG aie ches ote cal ates S95 15 21 57-.58:161 weddellensisterSCUGOLAXG lis ie ch Seen ssn cede = eheiets casetiek et eae 40 WeddellianeProvinGeyacds tritici sucee meee sae re sae ee eee 14, 15 WOOGN AE Ranrsia tics eit) sytncpers gusustts cries an oney ape Cotatiecebees cuentas 59, 60 woodburnet, Marwickia .... . 8, 9, 11, 24, 57, 58, 59, 60, 62, 3 WOOL CL MECUITLUSTESAINS Devs us Cet eliou et clash Newel sien chee ra istone (peta ee attics eeests D5eOs, LOS, 127408415 75,585, 59,60: 905 91 9 PLA EIITTT Lata ONG, So One Ss LOM ds 2. 27259608 618258325 ZElANdICA LCLCTOLETING w=. = verdes cis eis) eye segs is eve ds io) «ue 37,38 Zelandicl aimed teh ass eichen seca eet ct Fae Neosieiis- shes 2) ke yous 39 Le LAN GUIES2 Peng ria, WC e ese et hes) SUED oes aed Grete Meunrehads ehstens 8 LEAN ATE SAV AKIN Qarmerras ies use cosh eh ene athe pita kee eee ken eae, are 8 Aes, AVA PAO om ORGS Coo Re Coo Ue oe ao 47 ZOTOASTC Tg eR EN ET ee ee eT Maes ial Meer ap sre erie 15 Zygomelon....-.... 5, 10, 12,47, 57, 58, 59,60, 64, 92,93, 10 LYS OMELONRAD HELE SEs SPs mete tok wee een Red Pease Rye tet eten sa sed ie Sed euaERl ee duoesliepeeehoos 5; 10), 12,475, 57, 58; 60; 64,:92,93, 10 Zygomelon suropsilos (Stilwell and Zinsmeister, 1992) ..... . 47 Zygomelon zodion Harasewych and Marshall, 1995 ........ 47 PREPARATION OF MANUSCRIPTS Bulletins of American Paleontology usually comprises two or more sep- arate papers in two volumes each year. 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Begun in 1895 NUMBER 368 DECEMBER 30, 2004 Carboniferous (Visean—Moscovian) Echinoderms from the Béchar Basin Area of Western Algeria by G. D. Webster, C. G. Maples, G. D. Sevastopulo, T. Frest, and J. A. Waters Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York 14850 U.S.A. ISSN 0007-5779 ISBN 0-87710-464-6 Library of Congress Control Number: 2004098888 Note: Beginning with issue number 356, Bulletins of American Paleontology no longer designates volumes. The journal publishes approximately 2—3 issues per year, each of which is individually numbered. Printed in the United States of America Allen Press, Inc. Lawrence, KS 66044 U.S.A. CONTENTS Page PADS (AG (pee eR RM Re eMC RU MCMC use RLS ou cee ihc an cs vay Tuca sbirsirans sitar Ceue hears, Sake, Se tsi eT AS NSLS US foo Li goats eis la tee Sayan eee ewe Se 7 NiO ANG C1 OMe arias eno ea cease ey ad ssscete re ete cetrs esa sof Juste ins. clo eeu a sar ce ehrey sa dea ug dl Sigerradle, siychiea soa ciestye snow apts epee cake Rapeaien coals 0: Bs nyse aasueghoceaieutes 7 PACKNOW EG SITIONS petra ge Regge ce wage cron asc Bey eonYscigs ac dges(ss cig sefok eu Sp sgetge ree Sass Satie loalee SASF cs Wego uepatic as ah si Reta ame ual eigicaro Gals owls rnse RONG See sees 8 Ralinalgsipiin Cancerandy COmpaulsOUSss ge cneicqe rate ae sy ace easyer sh ct aee ici, ie sere oiislenteciare cee oe erecta eieecie nie Guoimcudicmvine GLP euse 8 PNK AGH Am OTA ONE QVASCAM) kere. twee ct wtan goM cise ghia 2 2Rs ep au ucT VCR cam aise asks ce tenis ve rel ie ueNG EE bc UTS eS eS Ya ovr nS 10 ZOUSTAN APE OLIN Atl OMigmeae mee eRe WSR Sc Pech sie oikd Sse eh SYS, Sf, ae wis Sie se cay eee awe SH a ewe oo SM pire: wade sa cgeecheahe pep ene eadac oe oe 11 EGuelmounashormationh 57.eecctesasteve ste ehegece v2 se asrtssiohseenleiie sy cba epg (8) Sy seh-n zs se! Gite od douse ed Seeley sigah okey Rn Sasso Meye Eom gees ehewewie dh wvoael 11 PAinIne levi. DBISO TIN AtLON ewes sare eee gh ane aemeteme Cerca ash ssiues Site fous eides Saas er sl cies Sk Soa apee ocisoote nen cea oe oie SR Seo aon Bers oe aici 12 DyenicnkPonmatlonweek en ne nr mea cesta eee ewer, creas sik eke oa deok siete < mance ie Ores CERIN Renae, Coy OP ds Se Re 12 laonanayeormationWate:Serpukhovian—Early Bashkiriam)) 2). 23). cea ce 2s om Gea ebsicieue = sais eee el) yalea suai s wicvaiveisuacdle eleere- 13 FTassigWenrmay hOnmatl Ont mucnntecvone aus skRR Re enCnN ci felis 5 gov es 8g. avets reyes fsuse to 2) Mites Susie enenersiovies clus Ease Meus sencaewe cs We ycrienaae ote ee 13 @uedkelsamargeormati omteywegewes 8 uces see ers sites nsksms cits) shes h.3 -euisiueh arenes ce syrah ts Wy dS cours aso) oda ose sen ateweny eB ons ans@ ae Stews ae ee 13 OnedsB elfGrounkkornmationy(Moscovian))seeemneerer seis clei ciere oieieel ces atee. <1/-veuei sictesis cite: sticks) © ovis oe ete neye Skee ery renen yeaa on aeres 14 AUT AES UM ITIVE Me LARP Netcare Meet es ey spp wwe ee Hace fue! seedy d4 shaigay Sued ct dim aweste eon anid a) Sueregauey new aeen Lee Spates ewe eho: RA ORAL 14 Systematicalaleontolopyaesmee snare aber e ween Pes Mi we ted Htecilasce nay Stossel eloy-o) cv Alar as afar acet ai ciesne cer va See Weg cea NR egnepeatior nie noon ea elaatte 15 WARSI n'y Ga Aid ceo GUA Olt OED oho EOD A Chose SIRE ree aCe Ie Er ae Ree eared en Sm ee a OU GO ee ee 15 SLC HININ OOS Epa yaa Mem Wary ret LAL Aee wake Reet meee MMe Metis we ee) al elcid ote nrsne ofp yh. i'g-tv chicive. cx ot aheoneccot Si valRs eRe WATE eatee VOD ms Eareuate Pay ae EARNS 15 (CHEGSIUNCEIROE a Stoon ot achd Gite. cacid-e, aici cotiec aici ch Osc) Gr ONte oie a men en ea eo Ren CET mPa Go ee ene 17 IREDOSILOGY MEM te RMN PM Tr aes SE esi en PT Ne Teeny) ete Me iistiekrey'e tai alts bavay cnalae chard) saliaiueh aller outtaliaivan an A a cues cgay iene che eS en She ie ana 17 Subphylum a GrinOZ Od larger tee eee yee MurNe ie me we nee dee Ih he, Arms Sar lc alg anc caviow eine iench ‘Zistantey th ASS (ar Shae CaP ee per PRESS eae awl 17 GlassaB lastoldeal ee eee he RMR RRC Ce PR ote RT ere rire ar Seat ae Least ayfo.ssh aianec oN ayar ie sdetetvav al a Coulee col cer auch saveeemeu tapes ope cored osmenses ae 17 Orderghissiculatayeyyertom ter teeey a et teb es eee eis ley cx. cies castielins ey aah) sis cu ade wits Gus aldnay ot bel besa eeily meester ay Ausra, mw Ai aw ee Ph all 17 Ramilysenaenoschismatidae mrmum wire hein cnc cr siie catty orrensics cuseradussieinise gee onrs cayrscane Suc ue ce teaae] cul ee elec eeove etree nee emer ere iN9/ GenusaKory sGhisrri clase pew mente wm tL see cas Soh epee tay oi ciate ai Geahie eal Tonaiveviat Oise ducer woth, ae aa W eheae a ROR oS ER ee ee 17 Classi @rinoideam ew cecherca tele een eM RSE woke een ea eRe IS sale boro iat 4) 2 RTS OS Sng) Shale atuatio aD. tye Ey SRNR comcunaees outs Sap eee MARRS eps 18 Subclasse@ameratagepa mpm cut re ae ete Pe cnet cura An feats fe chicelsuge 3, sry Gia, abicite ot sei Gec ease cute ier Cone Nene ead aeRO EL RB hu fereste 18 OrdenDiplobathridagieememssce gtk eey eee ee tac eee ke ees ea sTon Cal 6 SL sense akg te Ne ceca gh je LO Mey OVENS ROR TS SENT Seco 18 Supertamilyanhodocnnitaccadmrry as-is esas amar sere te et fcaket oc) acioys carecinite euer ous Go ian tRSac een es nee aero ey CoN eee AO 18 | SetaaP NGI eeVays foyoratabiavel:\ohy So niank Bate ae cen Ouaiey cs Ged hl o-O. Cee ee eM LCE an eee Teme Sait Ges Bid comico a 6 eee 18 GenustRnOdocninite sie hela oe etc cue ere ueMsrs ie ei 8 Synth e Late avin reyte, eros PENSE 5 (57S ey eu em erate eee enone 18 OrdersMonobath rid ates cet et eesuere ees te eyes ueteteworecha toe omaha” 5: f5ic2\ al sue cs, sete deta Goeue aay ncomells selec oemeesl Gign dee Sagem oon tet aot Pee 19 Suborder CE OMPSOCKMIN Aime wersreeeye yen tw MeN een ee Wek he chess course NIG sh a oi oete eee er sae ee se vag Ra 19 SupertamtlypPerechochinaceauencpam tne Romer teuoteas is. Mens) cases i ay.chance eksieuevis alt eeerote mele Cy Wen ae Ree RMSE: ewe use: 19 Ramil yararap anicOCrinid ac ise. wewe se eM estcny Sae tary eae site. 8 canola pin cnn cs ae cahoae eaeee oie Coreg MOA og aN OPERA Mache Gare eae 19 (CUTS JVB Ae OT AT OTOR fot. ag close G10 EFS OIC CRE OLN te Chaka a ee aCe rear eaes Siena) ao Ok. Ger Oma Ee 19 Rarmithy@Atn PHOLACTINIG AS are aatcrsigsyasrs eskicy cyetepiehsuisue eyiestssie asec. 2 ena) 5) era (e4roc seh od, ch cbeeushegelte go noterewai teu saent Wake i ee aee rrouce ene eses 19 (GENUSRE CLOCK IMU Serer mice nays, Sep ey RR Teen oe Mois one cs Shei TEE SSeS, Se eE ANS Som Tee a ER Se Ri Ee hac ik) RamilyeActinocrimitid aces arate cy aawacr st siesus cocus eye. cece Sis) sice sd Fiscaases fi angels sare sameness oh aCrtier nace reat eemereh areata gee ESO IEY sc 23 Subfamily eA Ct nOCGIMItN ae emer etree Teac R ten oi She, cyan) scree st AG Ne GEO SLOTS ORE CPR RR Se Oe Nae its 23 GenUSPACINOGHINILCS? agers ema eM eS ee RET eB LO. 55ST SES Ls eRe OETA ee ope REI ME Ries ee ces ere 23 GENUSFACCOCTIMUS EH pore urn y Ne Bop men ore ae es cice hho Oke ieee bok as feed as BAS ROL IS eI ROTEL RE ee oes 24 (GEMUSESAINDS ONO CIINUS Wer weyers tn Sees Te Syed ate Si Sak. SNORE A) oe eta eas Rae cae cg Re ene ies ses 26 (GENUSTBIGINOCHINUS Iecwe face ener cays ste reasasceier See ahse 51,5: Fai. os, 8 aden ie aMeaarier a ae ore sade CRA RAP Poe Sosa chen ale eeere ate 27 GenUseRinliCOCTIMUSie seas tenns csp Oe ati eehs Gis. 0 E.S S NAS Fy Beep tila Peds ek iol ae eae eee PAOLA dhe nD Pace: 28 Suborder Gly ptocrininavewswyenarene es vache rare) sense fee ners rau tana Titec Aue PAE ee Se NL pee SITUA See ous ales. chanuesoetyNe 31 SupenfanilyaPlatyComitaceamew neue taxarwsh pe ee Neneh Fwyei th cies afc, 1ay Sues, nue) gy seetsuech epee one ute elem ous eee receas EASNE coast eae Teese ovo wut enh 31 RamalyiPlaty cninitidace cre cr steusi =) yatsertc mie eit to sie) sein) ) sae) wer ols trcmateyie) cue © cumyeusteMenseeamte tus ue coin, s fei earer eee sv see ious 31 (GenuseRlaiycrimile sis ays re- ta cg eesh sc cke cere 1551608 B58 eevee, arn LeRe abet © lek ode Me avers Piraeus tee Ae Sun nlc aidan ok skentewks Sil (GenUSPR LEU OCTIUS tern teh caret PYM Red ory Gace. Go es 6 lo ey 0 6) Sie Ne LM CCR RET EAE HE REMORSE ESN ER. ae 155s eens aa ies Toni Sew 36 GenussEUClAdOCr Inu Smear eet Were Fre eS Oa sc ae I UR a RE RI OE eee ees ey eaten aadeel eed ee 38 SubclasssDis paridarwweergeaa lee aera ke gee he ss eilsric hosts (aicese aie. nu rite lenabaaclcyee aa Cae gtune, Stedesct eee Hit on Goisios piu med sedurets 39 Supertamilyeb clemnOcnnacealacreaawms cer save creas ceive cis ered tors RRM MM Ieee een cr ener cia ns sous: d erteaie cobs fone ey er ovals 39 Ramilya SVD bathOCrini dae ware ee wen wees once oes ie ox ses min See CS en POR ENE Pits nee ei te nas eer my eteuemerttasien songs 39 (GENUSES VP AINOCT INS eae eee MERE as rhe. 2 eee RRM RETRE OP TELE: Coe geo otch Sos Ciceiovos ENS Ean 4 39 SHOES GIEGTGH 243 ola ora.o eae OAGn Gcee 1s See COURT OE SIS RSG 8 esr ce Po oe tere 39 OrdenGy athocrimidalmersrsreccnsteereeheee, oh tt teme, w,5 vriceil se es sltskovic) oa sens taka else titeh Mesh ol oi erelias such ous a Rie yas c) clients Shese buts @ prennd eae 40 Suborder Gy athocrinin ata srt eer eic. sews Aca cue Csiene ere ekemeamaie Maven cane pide ebin st aredsrar el aycanaislacenaon Afra hh opble a Mose eroue)s 40 Supertamtlya@yathocrimitacedmspayeuet elawssie ere scectousvapetedce seek ete eee ae Hari aici iie au cic aaa ty ica av Susivay 4) a ahusvian Shee te: GLa aMlayers 40 Family sBarycnmidae. .).e 4 a-)aee2e oe es Saeed Lee ere RE MRM ee you sae KeLoee) shatters son GiGi es oh rcv ian Selene ede ene) Sisweuapenel ous 40 Orde Mendrocninid ameew meena ee iPr re ee Alene eI NRE tee eer NA or iS) Se essuv wg si lAlgg Gav. Geeteyaincll eae Gudeavs 40 4 BULLETIN 368 SubordersDendrocrininage vans. sree dee aa cane tlie orate melee Moco t remot SL eRe etme een a Aaa Reiki sy eos oats ene etek eae cmede 40 SupestamilysMastisocrinacea sar ianertts si) cichsee) sl mcath ace peer taser eg Re eee a Rene aN RR Rel priest kche onan er Nees 40 WFamiuly, Mastigocrinidae: <3 /4ch ess sueus ono) csdye alt ences eyed aula lea es sclrewepemcnchie ets ota sila aiAkcyeinel setae lisa sutae-ee ede st eyes 40 GenusvHebonenocrinus;ynec Cena. is cicts tele sceteh ene sadn ue nchen nem er Rte uot kere Pusat eet ed Renew one k shee nen htt ee eee 40 lec heevi bial cole glove ab sialol: eet Mretene irre Cee aves unread AO Gite DanC OIG OO H0 GOO OOOO OSA OO MAT OG oo doa 41 Genus Balearocrinuss as arco Robie she PONT eee. ha Oo LO a BT fo Ree NETO Te Rye Ie oh eae Ree 42 Superfamily *Scytalocnrimaceat ss. acre em edoa mie eematoie en mck ego mee: Goknacnweae Gheuene con eso keucie) ee cieie nic ceeci ek ieee 43 RamilyaScytalocnmidae - 6.65% Sensei so tte dole: aus emtceneay aa orcs, SWemeyemesnrs eae neem a iets) Magelgey as tates an eat 43 Genus: SCyLQlOCTINUS: > ; S. - «Pp BEN ZIREG -- —~-—- > i] e Sh eee Se eee eae (eo) ea Ag Fen, _ BECHARe = «| OL Soe St « oie _.~. Hassi Kerma x WOR . . coPeee ee Bibs Djenione g. ¢ ele Ain el Mizab ae Oued CG = {4 Ge 0, « el Hamar} & ep, “e we ise SA eT ? s “Ope Ce te > ) Mm oa Ain 2) Arkr % ey atl N i} 2 SS ~- G,,\Mezerelt a» joes: -. Ch. Kouabi Bey S ) \.@ a Teniet el Aouldja rt ‘ ioe oo hee ~. = Se ese on y ee Sipe f , Meharez eae oe d al So ane ees 3 ear) Sc ak (Oe ar INS ~ Sena Dj. es ERG de TAGHIT 2: loucha.- > ay) ty ~~~ e Taouerta q] Ie gh “Ny “y @ IGLI 29 Harreze % ~ @ a < 12) 49 ) 1°) Text-figure 1.—Map of the Béchar Basin showing named topographic features of echinoderm collecting localities (modified after Lemosquet and Pareyn in Weyant, 1985). 10 (PART) PENNSYLVANIAN | | — (PART) MISSISSIPPIAN MOSCOVIAN BASHKIRIAN SERPUKHOVIAN OUED BEL GROUN OQUED EL HAMAR BOULMANE AKACHA IN iM if a a Sat BULLETIN 368 r 1000 m 77 500 m Om and abundant pluricolumnals in the collections might provide additional support for minor distances of transport or sorting with transport unless their absence reflects collection bias, which is a real possibility for columnals which are often considered to have little paleontological utility. The extent of collection bias is uncertain. It is con- sidered a strong factor concerning the lack of colum- nals, however, because it is uncommon to find cups and thecae without associated columnals or pluricol- umnals. Until the Algerian area is more accessible for recollection and study, questions concerning collection bias with sedimentary and environmental relationships remain unanswered. Each of the 18 faunas listed (See Appendix, p. 70) is followed by comments on the diversity, dominance, and comparisons to equivalent faunas. It should be noted that none of these faunas compares with the large diversity of some time-equivalent faunas from Scotland (Wright, 1950-1960) and the United States (Bassler and Moodey, 1943). Stratigraphic information is insufficient to determine the exact horizon from which a few of the specimens were collected. These specimens are indicated by an asterisk (*) and are in- cluded in all of the faunas in which they might have been found. Columnal taxa are preceded by the symbol @. Numbers in brackets following each taxon are the number of specimens. The faunas are discussed in or- der of oldest to youngest (Text-fig. 2). Akacha Formation (Viséan) Koryschisma saharae (Breimer and Macurda, 1972) [1] Ectocrinus rouchi (Delpey, 1941) n. comb. [11] Barycrinidae? indeterminate [5] Balearocrinus pareyni n. sp. [1] Cromyocrinid? indeterminate [1] Cladid indeterminate 3 [1] Sagenocrinid indeterminate 2 [1] The fauna of the Akacha Formation is moderately diverse for its small size. It is dominated taxonomi- cally by cladids (four species); however the most abundant taxon recovered is the camerate Ectocrinus rouchi n. comb. (11 specimens). Unfortunately, pres- ervation of four specimens precludes generic identifi- cation; however, three of the four can be assigned to a family or order. Although specimens of Koryschisma Text-figure 2.—Stratigraphic column of the crinoid-bearing parts of the Mississippian and Pennsylvanian strata of the Béchar Basin area. Standard lithologic symbols used for limestone, sandstone and shales. Section modified after Pareyn (1961) and Lemosquet and Pareyn in Weyant (1985). For member subdivisions of the Zousfana through Oued el Hamar formations see appendix. CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 1] saharae were not included in specimens studied, one specimen from the Akacha Formation was reported by Breimer and Macurda (1972) from the Pareyn collec- tion. This is the oldest occurrence of K. saharae, also known from the Ain Mezerelt and Ain el Mizab mem- bers, ranging from the late Viséan into the early Ser- pukhovian. The genus is also known from the Kin- derhookian (Tn2) of Montana in the western part of the United States (Sprinkle, 1973), from whence K. saharae was apparently derived. Ectocrinus rouchi and Balearocrinus pareyni n. sp. are related to equivalent-age species in England and Spain, respectively. Barycrinids have been reported from the Devonian (Emsian) of Spain, the Mississip- pian (Osagean and Meramecian) of North America (Moore and Teichert, 1978), and the Tournaisian of England (Wright, 1942). Pentameric columnals as- signed to Barycrinus sp. were reported from the Chad- ian of England by Donovan and Veltcamp (1990). Cromyocrinids are most abundant in the Pennsyl- vanian, but Viséan taxa have been reported from the Mississippian of Russia, Spain, England (Moore and Teichert, 1978), and the United States (Kammer and Ausich, 1993). Sagenocrinids are known from Missis- sippian faunas of Europe and North America but usu- ally in small numbers. Thus, the Akacha fauna has affinity with North American and European faunas, more with the latter. It differs from most middle Vi- séan faunas by the small number of camerate taxa but reflects the increasing dominance of the cladids over the camerates throughout the Mississippian. Zousfana Formation Ain Guettara Member (Late Viséan) Actinocrinitid indet. 2 [1] The single specimen of an actinocrinitid in the Ain Guettara Member may reflect an isolated preservation. The specimen is probably from the top of the Ain Guettara Member from the limestone overlying the sandstones. Actinocrinitids were at their acme during the late Tournaisian and Viséan. El] Guelmouna Formation Ain Mezerelt Member (Serpukhovian) Koryschisma saharae (Breimer and Macurda, 1972) [3] Rhodocrinites sp. [1] Ectocrinus mezereltensis n. sp. [9] Ectocrinus redactus n. sp. [1] Actinocrinites becharensis n. sp. [1] Actinocrinites combinatus n. sp. [1] Platycrinites reouienensis n. sp. [2] Synbathocrinus sp. [1] Zeacrinitid? indeterminate 2 [1] Pareyn (1961) recognized a vast meadow of crinoids dominated by camerates in the Ain Mezerelt Member in exposures in the E] Guelmouna Basin. He reported (p. 72) five species of camerates, differing from our identifications. We assume that the taxa listed, but not illustrated, by Pareyn are included within the species we have identified from his collections based on the stratigraphic information. In addition, Pareyn (p. 89) listed six taxa from the El Guelmouna Formation at the cliffs of Ain Tagnana. Stratigraphic information with two of the specimens Pareyn listed as Synbath- ocrinus nov. sp. and Zeacrinites nov. sp., here identi- fied as Synbathocrinus sp. and Zeacrinitid? indeter- minate, indicates they are from the Ain Mezerelt Mem- ber, where we have included them. The Ain Mezerelt Member fauna has a strongly cos- mopolitan composition. It contains four equatorial-belt cosmopolitan genera, which are considered by us to have had wide ecologic tolerance limits. Actinocrini- tes, Platycrinites, Rhodocrinites, and Synbathocrinus were cosmopolitan in the equatorial belt during the Tournaisian and Viséan. Camerates dominate the fauna of the Ain Mezerelt Member. Rhodocrinites sp. prob- ably was derived from Western Saharan Devonian or Moroccan Viséan species and is related to Scottish, Russian, Chinese, and United States Tournaisian and Viséan species. The two species of Ectocrinus are de- rived from E. rouchi and closely related to English and Irish species. The species of Actinocrinites and Pla- tycrinites are related closely to English, Scottish, and North American species. Although zeacrinitids are known from the Viséan of England and Scotland (Bather, 1916), most are known from the United States where they reached their diversity acme during the Pennsylvanian. El Guelmouna Member (Early Serpukhovian) Pleurocrinus glomerosus n. sp. [8] Cosmetocrinus? sp. [2] Dicromyocrinus vastus n. sp. [19] Ureocrinus commus n. sp. [1] The El Guelmouna Member fauna is dominated by cladids. This may be a reflection of a high clay content in the living environment as the El] Guelmouna Mem- ber consists of claystones in the lower half and dolo- mite in the upper half. Pareyn (1961, p. 89) listed two cladids, Phanocrinus nov. sp. and Aphelecrinus or Fi- feocrinus sp., from the El Guelmouna Member. We identify these specimens as Cosmetocrinus? sp. and Ureocrinus commus n. sp., respectively. Pareyn (1961, p. 89) also listed two flexible crinoids for the El Guel- mouna Member; however no flexibles were in his col- lections for our study from the El Guelmouna Member. The El Guelmouna Member contains the oldest known 12 BULLETIN 368 occurrence of Dicromyocrinus, extending the range downward from the Morrowan into the Serpukhovian. Ain El Mizab Formation El Harrada Member (Early Serpukhovian) Ectocrinus sp. [1] Mooreocrinus glomerosus n. sp. [2] Zeacrinitid indeterminate | [2] With two cladids and one camerate, the El Harrada Member fauna is similar at the subclass level to the El Guelmouna Member fauna and is another low-diver- sity fauna. The El Harrada Member is oolitic in the middle and yields crinoid remains in the thinner bed- ded lower and upper parts (Pareyn, 1961). Pareyn (1961, p. 89) listed Amphoracrinus nov. sp. from the E] Harrada Member from the cliffs of Ain Tagnana. We identify the specimen as Ectocrinus sp. The El Harrada Member contains the oldest recognized oc- currence of Mooreocrinus, extending the range down- ward from the Morrowan into the Serpukhovian. Ain El Mizab Member (Middle Serpukhovian) Ampullacrinus tritubulus n. gen., n. sp. [1] Palaechinus sp. [1] The echinoderm fauna of the Ain el Mizab Member is small. Ampullacrinus tritubulus also occurs in the upper part of the Djenien Formation. This is the lowest occurrence of Ampullacrinus. Mouizeb El Atchane Member (Middle Serpukhovian) Koryschisma saharae (Breimer and Macurda, 1972) [3] Megaliocrinus? sp. [1] Platycrinites aouidjaensis n. sp. [2] Seytalocrinus sp. [2] Dicromyocrinus vastus n. sp. [1] Mooreocrinus glomerosus n. sp. [2] Ampullacrinus marieae n. gen., n. sp. [4] The Mouizeb el Atchane Member fauna is a mixed fauna of moderate diversity. Cladids taxonomically outnumber the camerates four to two. It contains the youngest occurrence of Koryschisma saharae. Mega- liocrinus is known from this fauna and from some Spanish middle late Namurian faunas (reported as /b- erocrinus by Sieverts-Doreck, 1951, and referred to Megaliocrinus by Strimple, 1976). The greater abun- dance of cladids again reflects their increasing diver- sity in the late Mississippian and a high clay content in the sediments. Pareyn (1961) reported crinoids oc- curring in the uppermost thicker bed of the Mouizeb el Atchane Member. Specifically, he (p. 76) reported three crinoid taxa. The camerate, listed as Amphora- crinus nov. sp. A, we identify as Megaliocrinus? sp. The cladids, listed as Phanerocrinus [sic] nov. sp. and Cf. Fifeocrinus tielensis, we identify respectively as Scytalocrinus sp. and Ampullacrinus marieae n. gen. n. sp. Djenien Formation Hid El Kef Member (Late Serpukhovian) *Platycrinites aouidjaensis n. sp. [1] The faunas of the Hid el Kef Member, boundary beds of the Hid el Kef and Djenien members, and the undesignated part of the Djenien Member are perhaps isolated occurrences. Pareyn (1961) reported crinoids from the green shales of the Hid el Kef Member. The importance of these faunas is the occurrence of Hy- driocrinus? confusus n. sp. in the boundary beds of the Hid El Kef and Djenien members and Paianocri- nus?) carinatus n. sp. in the Djenien Member (undes- ignated). Although the generic assignments are ques- tioned, as explained in the systematics, these forms represent taxa not recognized in any of the other Al- gerian faunas. They provide significant paleobiogeo- graphic information and provide new evolutionary lin- eage links. Boundary Beds of Hid El Kef and Djenien Members (Late Serpukhovian) Hydriocrinus? confusus n. sp. [1] See comments under Hid el Kef Member above. Djenien Member (Undesignated) (Late Serpukhovian) *Paianocrinus? carinatus n. sp. [1] See comments under Hid el Kef Member above. Upper Part of Djenien Member (Late Serpukhovian) Actinocrinitid? indet. 5 [1] Platycrinites djihaniensis n. sp. [2] Platycrinites cf. P. djihaniensis n. sp. [4] Platycrinites sp. 2 [3] Ampullacrinus tritubulus n. gen., n. sp. [2] *Paianocrinus? carinatus n. sp [1] Cibolocrinus africanus Strimple and Pareyn, 1982 [3] Amphicrinus formosus n. sp. [2] Pareyn (1961) reported crinoids occurring in thin dark detrital beds that are interbedded with massive white limestones. At the generic level, the fauna from the upper part of the Djenien Member contains two camerates, one cladid, and two flexibles. This is an unusual faunal assemblage in the late Serpukhovian, as most faunas of this age are dominated by cladids with minor numbers of camerates, and even fewer flexibles (Bassler and Moodey, 1943; Webster, unpub- lished compilations). Most late Serpukhovian diverse echinoderm faunas are known from North America such as the Glen Dean Formation (Bassler and Mood- ey, 1943), Pitkin Formation (Strimple, 1951a, 1978), Bangor Limestone and Monteagle Formation (Burdick CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 13 and Strimple, 1983), and Sloans Valley Member of the Pennington Formation (Chestnut and Ettensohn, 1988), among others. The few late Serpukhovian cri- noids reported from Russia and Europe are often sin- gle-taxon occurrences. Cromyocrinids are rare in North American faunas of late Serpukhovian age, whereas scytalocrinid genera generally dominate the cladid-dominated faunas. This upper part of the Djen- ien fauna is more like Meramecian faunas of North America, which have higher camerate diversity with cladids and rare, but fairly ubiquitous, flexibles. Tagnana Formation (Late Serpukhovian—Early Bashkirian) Hebohenocrinus quasipatellus n. gen., n. sp. [1] Dicromyocrinus vastus n. sp. [2] One dendrocrinid and one cladid are insufficient to evaluate the Tagnana fauna with more than broad gen- eralizations. Hebohenocrinus quasipatellus n. gen., n. sp. 1s an endemic taxon questionably assigned to the Mastigocrinidae. The continuation of the cromyocrin- ids in the fauna is a carryover from older faunas. The exact horizon from which the crinoids are derived 1s not specified, but they are from the interbedded shales and limestones of the upper half of the formation. The Serpukhovian—Bashkirian boundary occurs within the middle of the Tagana Formation. Therefore, the age of this fauna is earliest Bashkirian. Hassi Kerma Formation Lower Part of Hassi Kerma Formation (Early Bashkirian) Dicromyocrinus? sp. [7] Cladid indeterminate 2 [3] @Floricyclus ct. F. angustimargo Moore and Jeffords, 1968 [1] @Plummeranteris? sp. [1] Taxocrinid indeterminate [1] Sagenocrinid indeterminate | [5] The fauna from the lower part of the Hassi Kerma Formation is mostly disarticulated cup ossicles, col- umnals, and fragmentary cups. This fauna is distinc- tive in the absence of camerates and the near codom- inance of flexibles and cladids. The continuation of the cromyocrinids corresponds with their common occur- rence in Pennsylvanian faunas in North America (Webster, 1981) and presence in 14 of the 18 faunas recognized herein. This collection and that from the upper part of the Hassi Kerma Formation are the only two containing abundant disarticulated ossicles, in- cluding columnals. It is not known if this is a result of taphonomy, collecting bias, or both. Upper Part of Hassi Kerma Formation (Early Bashkirian) Aacocrinus algeriaensis n. sp. [5] Aacocrinus algeriaensis? [2] Blairocrinus grafensis n. sp. [1] Actinocrinitid indet. 4 [5] Platycrinites hamarensis n. sp. [1] Platycrinites sp. 3 [1] Platycrinites sp. 4 [2] Platycrinites sp. 5 [2] Dicromyocrinus catillus n. sp. [1] Mathericrinus wallacei n. comb.[1] Cladid indeterminate 2 [3] Cladid indeterminate 4 [2] Cladid indeterminate 5 [1] Cladid indeterminate 6 [1] Cladid indeterminate 7 [4] oPlummeranteris? sp. [1] @Columnal undesignated [1] Amphicrinus prinsi n. sp. [7] Crinoid Indeterminate | [1] Crinoid Indeterminate 2 [2] Crinoids Indeterminate [17] Although the list of taxa for the fauna from the up- per part of the Hassi Kerma Formation is the largest of the Algerian faunas, it cannot be considered to be a true count of the number or diversity of taxa rec- ognized. Two or three of the indeterminate taxa may be from a single taxon, Platycrinites sp. 3, 4, and 5 may be parts of one or two species, and some of the columnal taxa may belong to one of the other taxa listed. The estimated composition of this fauna, occurring in limestones, is four camerates, six to eight cladids, and one flexible. The large number of camerates in a Bashkirian fauna is unusual. Most Bashkirian faunas worldwide either lack camerates or have only platy- crinitid columnals, which are often not reported. The occurrence of Aacocrinus is of particular significance because it extends the range of the genus upward from the Early Carboniferous (Osagean) into the Late Car- boniferous. Blairocrinus is also of significance because this is only the second reported occurrence of the ge- nus in the Late Carboniferous, the other from Des- moinesian strata of Japan (Hashimoto, 2001). Oued el Hamar Formation Lower Part of Oued El Hamar Formation (Late Bashkirian) *Pimlicocrinus octobrachiatus n. sp. [8] Pimlicocrinus sp. [1] *Platycrinites hamarensis n. sp. [4] Mathericrinus wallacei n. comb. [28] *Archaeocidaris sp. [2] Three of the taxa listed may belong in the upper part of the Oued el Hamar Formation, which contains 14 BULLETIN 368 a much larger fauna. If all of the identified taxa belong here, the crinoid fauna is camerate-dominated with an associated cromyocrinid and echinoid. Upper Part of Lower Part of Qued El Hamar Formation (Late Bashkirian) *Pimlicocrinus octobrachiatus n. sp. [8] Actinocrinitid indeterminate | [2] All of the small number of taxa are camerates. Ac- tinocrinitid indeterminate | may not be from this ho- rizon, but we are uncertain in which part of the Oued el Hamar Formation it may have been found. Upper Part Of Oued El Hamar Formation (Late Bashkirian) Sampsonocrinus cheguigaensis n. sp. [74] *Pimlicocrinus octobrachiatus n. sp. [8] Actinocrinitid indeterminate 3 [1] *Platycrinites hamarensis n. sp. [5] Platycrinites sp. [1] Pleurocrinus folliculus n. sp. 2 [3] Eucladocrinus? asymmetricus n. sp. [8] Eucladocrinus? sp. [2] Mathericrinus wallacei n. comb. [28] Cladid indeterminate | [1] *Archaeocidaris sp. [2] Even without the three questionable occurrences this fauna is dominated at the generic level by camerates. This may suggest, however, that the questionable oc- currences are from this interval. As noted above this is atypical of known Bashkirian faunas, and many of the same comments can be made about this fauna as that of the upper part of the Hassi Kerman Formation. The fauna occurs in a clay-dominated sequence of in- terbedded claystones and thin limestones. These li- thologies are generally cladid dominated. Of particular importance in this fauna is the occurrence of Samp- sonocrinus and Eucladocrinus. This is an upward ex- tension into the Bashkirian of their previously record- ed ranges from the Kinderhookian and Osagean. Oued Bel Groun Formation (Moscovian) Platycrinites? sp. [1] Dicromyocrinus? invaginatus n. sp. [5] Metacromyocrinus? sp. [1] Flexible indeterminate [1] The Oued Bel Groun fauna is the youngest known Paleozoic echinoderm fauna from Algeria. It is dom- inated by cromyocrinids, a group reaching their diver- sity acme during the early and middle Late Carbonif- erous. The occurrence of a platycrinitid in the fauna is not unexpected since platycrinitids, although rare, are found in the equatorial belt worldwide throughout the Late Carboniferous (Bowsher and Strimple, 1986). FAUNAL SUMMARY Several generalizations may be made when com- paring the various Algerian faunas to time-correlative faunas worldwide. The Algerian faunas provide con- siderable new interpretations regarding evolution and paleobiogeographic distributions of some taxa. With the exception of Koryschisma saharae, Ecto- crinus rouchi n. comb., Mathericrinus wallacei n. comb., Cibolocrinus africanus, and @Floricyclus cf. F. angustimargo, all named species in the Algerian fau- nas are new species. With the exception of Rhodocrin- ites, Ectocrinus (as Amphoracrinus), Actinocrinites (as Actinocrinus), Platycrinites (as Platycrinus), Pleuro- crinus, Cibolocrinus, and Archaeocidaris this is the first report of Megaliocrinus, Aacocrinus, Sampsono- crinus, Blairocrinus, Pimlicocrinus, Eucladocrinus, Synbathocrinus, Hebohenocrinus n. gen., Balearocri- nus, Scytalocrinus, Ampullacrinus n. gen., Hydriocri- nus, Cosmetocrinus, Dicromyocrinus, Mooreocrinus, Metacromyocrinus, Mathericrinus, Paianocrinus, Am- phicrinus, @Floricyclus, @Plummeranteris, and Palae- chinus, from North Africa, extending geographic rang- es for various genera from Europe, North America, Russia, China, Australia, and Japan. The stratigraphic ranges are extended downward into the Serpukhovian for Hydriocrinus, Dicromyocri- nus, and Mooreocrinus. Hydriocrinus was previously known from Desmoinesian into Virgilian strata. Di- cromyocrinus and Mooreocrinus were previously known from Morrowan through Desmoinesian strata. Stratigraphic ranges are extended upward into the Bashkirian for Ectocrinus, Aacocrinus, Sampsonocri- nus, and Eucladocrinus. The upper range of all of these genera was previously recognized as Viséan. Four species in the Algerian faunas are reported from more than one horizon. Koryschisma saharae ranges from the Akacha Formation into the Mouizeb el Atchane Member (Viséan—Serpukhovian). Dicro- myocrinus vastus n. sp. occurs in the El Guelmouna Formation, Mouizeb el Atchane Member, and bound- ary beds of the Hid el Kef Member and Djenien Mem- ber (all Serpukhovian). Platycrinites aouidjaensis 0. sp. occurs in the Mouizeb el Atchane and Hid el Kef members (both Serpukhovian). Ampullacrinus tritu- bulus n. gen. n. sp. occurs in the Ain el Mizab and Djenien formations (both Serpukhovian). Actinocrinitids and platycrinitids were exceedingly abundant during the Mississippian of Europe and North America, as shown on the distribution lists com- piled by Bassler and Moodey (1943) and more recently reported in China (Chen and Yao, 1993) and Australia (Lindley, 1979, 1988; Webster and Jell, 1999a). Actin- ocrinitids and platycrinitids were essentially equatori- CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. ] al-belt cosmopolitan taxa during the Mississippian. Platycrinitids, although they became less common, continued as equatorial cosmopolitan taxa through the Pennsylvanian and into the Permian, whereas the ac- tinocrinitids were restricted to the Tethys during this time. Actinocrinitids have been reported in Japan (Hashimoto, 2001) and Iran (Webster ef al., 2001) from the Early Pennsylvanian (Morrowan or Bashki- rian). Although their occurrence in Algeria expands their paleogeographic distribution within the Tethys and explains where they continued to evolve during the Early Pennsylvanian before their presence in the Permian of Timor (Wanner, 1916, 1924, 1937) and Late Permian extinction, a large time gap still exists between these Early Pennsylvanian and Permian oc- currences. The actinocrinitids must have been some- where during this time, but where remains to be dis- covered. Disparid crinoids are minor elements of the Algerian faunas, occurring in two of the oldest three faunas. Cladid crinoids taxonomically dominate the fauna from the Akacha Formation, but do not occur in abun- dance. Balearocrinus is also known from the island of Minorca in the Mediterranean and appears to be a western Tethys endemic of Viséan age. The dendro- crinid Hebohenocrinus n. gen. may be an early Bash- kirian western Tethys endemic. Cromyocrinids dominate the cladids in the Algerian faunas. The occurrences of cromyocrinids in most of the Algerian faunas, with the downward extension of the ranges of Dicromyocrinus, Mathericrinus, and Mooreocrinus, suggest that major evolution was oc- curring in this clade in northern Africa during the Ser- pukhovian. Although cromyocrinids are present in the Viséan and Serpukhovian in Europe and North Amer- ica, often they are relatively insignificant in numbers and diversity. Their greatest diversity and abundance are in the Pennsylvanian of North America (Webster, 1981). Scytalocrinacids are the second most common clad- id in the Algerian faunas, but they do not occur in abundance and are restricted to the Serpukhovian fau- nas. Some of the indeterminate crinoids in the upper part of the Hassi Kerman Formation may be scytalo- crinids. Recognition of a cladid crown with three en- toneural canals shows that evolution of entoneural ca- nals occurred in more than one clade, and by itself, is not a diagnostic character of the articulates. The oc- currence of the pirasocrinacid Paianocrinus? carinatus n. sp. possibly extends the geographic range of the genus from North America; whereas the occurrences of two zeacrinitids in the late Viséan Ain Mezerelt Member and the early Serpukhovian El Harrada Mem- nN ber show relationship with both European and North American faunas. Flexible crinoids are generally few in number and low in diversity, occurring in five of the 18 faunas of Algeria. Of particular significance is the occurrence of Cibolocrinus in the late Serpukhovian part of the Djen- ien Formation as reported by Strimple and Pareyn (1982), the oldest record of this genus. Cibolocrinus apparently spread from Algeria into North America, where it is known from several species during the Late Carboniferous and Early Permian. It reached its acme during the Permian, and is known from various shelf basins along the southeast (especially Timor), western, and northern margins of the Tethys, as well as Bolivia (Webster, 2003). This is the first record of Amphicrinus from the Serpukhovian. It was recognized previously in the Viséan of Scotland and Russia and the Morro- wan and Desmoinesian of the United States (Webster, 2003). Archaeocidarid spines and interambulacral plates are common elements in many Late Paleozoic faunas, whereas coronas seldom are preserved. The preserva- tion of a partial corona suggests rapid burial of the specimen. SYSTEMATIC PALEONTOLOGY INTRODUCTION Generic and specific concepts followed herein are based on morphologic characters used in the Treatise (Moore and Teichert, 1978). Crinoid species are more variable than was realized by most researchers in the nineteenth and first half of the twentieth century. Where large populations are available for study, char- acters such as the number of arms, disposition of the anal plates, and degree of ornamentation are found to vary considerably (see, for example, Ausich and Se- vastopulo 2001; Lane 1963; Wright 1927). A character that is commonly variable in one clade, however, is not necessarily so in another. Where a large number of specimens were available in this study, as, for ex- ample, in Ectocrinus, it was possible to assess intra- specific versus interspecific variation. In the majority of taxa, however, large populations were not available. New species erected, however, are sufficiently distinct morphologically from previously described congeneric species that it is unlikely that they will be found to be junior synonyms. The delimitation of supraspecific taxonomic categories in crinoids in the past has not been consistent, and many examples of polyphyletic and paraphyletic groupings are evident in the Treatise. In this study, we have tried to ensure that genera are monophyletic clades. The characters that serve to dif- ferentiate genera vary from clade to clade. 16 BULLETIN 368 TERMINOLOGY Crinoid terminology follows Ubaghs er al. in Moore and Teichert (1978), with modifications by Webster (1974) and Webster and Lane (1987). Blastoid termi- nology follows the Treatise (Moore, 1967), as modi- fied by Breimer and Macurda (1972). Columnal nod- itaxis formulae are after Webster (1974), and measure- ment and curvature teminology are after Webster and Jell (1999a). Basal Cup and Proximal Stem The terms stem impression, basal concavity, and basal invagination have been used interchangeably and indiscriminantly by various authors in the past. For uniformity of description, we propose and apply the following terminology when describing the base of the cup (Text-fig. 3). Horizontal infrabasal or basal circlet.—forms a planar fused (one single plate) or articulated (two to five plates) plate at the base of the cup normal to the linear axis of the crinoid, irrespective of the living ori- entation of the animal (Text-fig. 3A). There is no flex- ure in the plate(s) although the exterior surface distal to the stem facet may contain elevated or depressed ornamentation. Stem facet.—is the circular or polygonal attachment scar formed where the stem attaches to the base of the cup. Stem facet refers only to the configuration of the attachment scar, which may or may not be horizontal and may or may not have a central depression (Text- fig. 3B). The stem facet may be flush with the external surface of the cup (usually the infrabasal or basal cir- clet) or, more commonly, at the base of an impression. Stem facet is distinct from articular facet. Articular facet is applied to the proximal and distal articular sur- faces of columnals, but these are easily distinguished in context, and usually referred to as columnal facets. Stem impression.—is the depression on the external surface of the cup (usually the infrabasal or basal cir- clet) formed by an inset of the proximal columnal into the cup with or without any flexure of the cup plate(s) (Text-fig. 3C). The stem impression may be filled by part or all of the proximal columnal and may become deeper with growth of the plates. Often the proximal columnal is preserved attached to the cup and when in a basal concavity may be difficult to recognize with- out having a cross-section of the specimen cutting through the stem facet. Basal concavity (= basal invagination).—is a dis- tinct flexure of the base of the cup, usually the basal (Text-fig. 3D) or infrabasal (Text-fig. 3F) plates, pro- ducing an invagination or concavity at the base of the cup with the stem facet at the deepest part of the in- Text-figure 3.—Diagrams of base of cup demonstrating plate re- lationship of stem impression, and basal concavity or invagination. Symbols and abbreviations: Basal plates in black; LA—linear axis, Si—stem impression, BC—basal concavity, PBC—pseudobasal concavity. A. Orientation of linear.axis of crinoid and “horizontal” infrabasal or basal circlet. Living organism may tilt to a great angle laterally or even hang upside down. Linear axis may curve laterally in one or both directions distally from circlet. Centrally positioned axial canal dashed. B. Exterior surface of fused infrabasal or basal circlet showing stem facet and central axial canal. C. Cross-section through axial canal of horizontal infrabasal or basal circlet with stem impression on exterior surface. D. Cross-section through axial canal of part of crinoid cup with horizontal infrabasal circlet with stem impression at base of basal concavity or invagination. Note the downward flexure in the proximal part and recurving upward flexure in the distal part of the basals (in black). E. Cross-section through axial canal of part of crinoid cup with downflaring infrabasal circlet with stem impression (SI) at base of basal concavity (BC) or invag- ination. The basals (in black) are recurved. F Cross-section through axial canal of an infrabasal circlet. Infrabasals downflaring proxi- mally and extend beyond the basal plane recurving distally flaring upward and are visible in lateral view. G. Cross-section through axial canal of horizontal infrabasal circlet with bulbous basals (in black) forming a pseudobasal concavity (PBC) or invagination. Note the lack of any downward flexure in the infrabasals or basals. vagination. Distal from the deepest part of the invag- ination the basal or infrabasal plates recurve to form the basal part of the walls of the cup. The distal parts of the infrabasals and proximal parts of the basals may be downflared (Text-fig. 3E) to form the basal concay- ity in some crinoids. Rarely the proximal parts of the radials also are downflared, such as in some genera of the Zeacrinitidae. To avoid confusion, it is recom- mended that stem invagination not be used when dis- cussing the cup, because invaginations sometimes oc- cur on the stem, such as where cirri attach. These could be referred to as stem invaginations although CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 17 they are more appropriately referrred to as cirral or cirrus invaginations. Pseudobasal concavity (= pseudobasal invagina- tion).—is the concavity formed by externally inflated cup plates adjacent to the stem facet without any downward inflection of the interior surface of the in- flated plates as observed in cross-section (Text-fig. 3G). In some instances, immature stages have a flat or upflared base. With growth, the plates become inflated and a pseudobasal concavity develops. Without an in- terior view of the stem facet, it is sometimes impos- sible to determine if a basal concavity or pseudobasal concavity exists. Radial Facet Width Terms to describe the relative width of the radial facet compared to the width of the radial are angustary, peneplenary, and plenary. Plenary has been accepted as the facet occupying the full width of the radial to the lateral suture with adjacent radials or anals. The use of peneplenary and angustary has been subjective and what one author might call angustary another would call peneplenary. The Treatise (Moore and Teichert, 1978, pp. 231, 232) defined angustary as “very much narrower than width of plate,’ and pe- neplenary “‘occupying most but not all of distal ex- tremity of plate, leaving nonarticular surfaces (gener- ally narrow) next to sutures at plate margins.”” In order to standardize the meaning of these two terms, we pro- pose that angustary be defined as occupying 70% or less of the radial width at the distal ends of the lateral suture of the radial with adjacent plates. Peneplenary is defined as occupying greater than 70% but less than 100% of the width of the radial at the distal ends of the lateral suture with adjacent plates. Cladid Anals Cladid anals have been referred to as radianal, anal X, and right-tube plate by most crinoid workers since the early 1900s. Prior to that time a number of no- menclature systems were used by various authors. Webster er al. (2003) used primanal, secundanal, and tertanal respectively for the cladid anal plates. Webster and Maples (2003) noted that the use of anal X is often a misnomer and recommended following the usage of Webster ef al. (2003). That recommendation is fol- lowed herein. CLASSIFICATION Problems within higher level classifications of Pa- leozoic crinoids have been discussed by numerous au- thors over the past 20 years, as briefly summarized by Webster (1997) and McIntosh (2001). Currently the classification is undergoing critical review by several crinoid workers, some of who have proposed different classifications (e.g., Simms and Sevastopulo, 1993; Ausich, 1998a). Modification of these classifications was proposed to include Paleozoic articulates by Web- ster and Jell (1999b). Undoubtedly there will be ad- ditional modifications within the next few years, es- pecially within the Inadunata, a subclass that was dis- carded by both Simms and Sevastopulo (1993) and Ausich (1998b). Also, there will be considerable change in the classification of crinoids currently in the Suborder Poteriocrinina, which may be polyphyletic and was discarded by McIntosh (2001) and Webster (2003). Webster (1997) discussed some of the prob- lems within the Poteriocrinina and considered the Family Poteriocrinitidae to be derived from the cyath- ocrinitids, whereas McIntosh (2001) considered the Poteriocrinitidae to be derived from the dendrocrinids. REPOSITORY All specimens are reposited in the Nationaal Natu- urhistorisch Museum, Leiden, The Netherlands, under six-digit numbers preceded by RGM, except as noted under Cibolocrinus africanus. Subphylum CRINOZOA Matsumoto, 1929 Class BLASTOIDEA Say, 1825 Order FISSICULATA Jaekel, 1918 Family PHAENOSCHISMATIDAE Etheridge and Carpenter, 1886 Genus KORYSCHISMA Sprinkle and Gutschick, 1990 Koryschisma saharae (Breimer and Macurda), 1972 Plate 3, figures 15, 16 Pentremites sp. Pareyn, 1961, p. 223-224. Phaenoschisma? saharae Breimer and Macurda, 1972, p. 18-20, 387, pl. 5, figs. 4, 5, 10; Macurda, 1983, p. 61-65, pl. 14, figs. 1-13, table 21. Koryschisma saharae (Breimer and Macurda, 1972). Sprinkle and Gutschick, 1990, p. 120. Diagnosis.—Theca large, elongate conical, L/W av- erages 1.71, pelvis much longer than vault, V/P aver- ages 0.23, pelvic angle averages 38°; deltoid crests low to medium, hypodeltoid large, other deltoids appear confined to ambulacral sinuses; ambulacra nearly lin- ear, lancet making up about % of width; 5—9 hydrospire slits per group, number reduced by % on anal side; subdued secondary deposits at tip of basals. Remarks.—The original description of Koryschisma saharae by Breimer and Macurda (1972) was based on three specimens collected by Pareyn from the un- differentiated Akacha and Mazzer formations, Missis- sippian (late Viséan, P2) at Djebel Ioucha (two spec- imens), and from the top of the El Guelmouna For- 18 BULLETIN 368 Table 1.—Measurements in mm for Koryschisma saharae. Spec. no. (RGM) 361 151 361 150 361 152 Length 24.5 19.4 16.63 Width 16.8 eal 10.9 Vault 5.65 5.9 5.65 Pelvis 18.85 es) 10.98 Pelvic angle 36 38 36 Length/width 1.46 1.28 1.52 Vault/pelvis 0.3 0.44 0.51 mation, Mississippian (early Serpukhovian, El) at El Guelmouna (one specimen). Both localities are south- east of Béchar in northwestern Algeria. These speci- mens are not well preserved, particularly in the critical oral and anal areas, making generic assignment ques- tionable. As a part of the discussion of these speci- mens, Breimer and Macurda (1972, p. 20) stated that if there is an epi- and hypodeltoid, this most closely resembles a new Lower Mississippian genus being described from Montana by James Sprinkle and Raymond Gutschick. They will re-assign it to their ge- nus.” Macurda (1983) provided a more complete de- scription of the species based on eight additional spec- imens from the same localities that were much better preserved. Sprinkle and Gutschick (1990) erected Ko- ryschisma for their material from Montana and reas- signed the Algerian specimens to Koryschisma sahar- ae. There is no indication that they had additional Al- gerian material to examine. We conclude that the specimens described in this collection are conspecific with Koryschisma saharae even though they are somewhat wider relative to length than indicated in the revised diagnosis of Sprin- kle and Gutschick (1990) and have a somewhat longer vault (Table 1). We will not repeat the detailed de- scription of the species from Macurda (1983) because our specimens fit well within the parameters given there for Koryschisma saharae. Although the current specimens are generally well preserved, each is miss- ing the hypodeltoid. The lateral margins of the am- bulacral sinuses are not preserved well enough to de- termine the number of hydrospire slits. Breimer and Macurda (1972) reported Koryschisma saharae from the Akacha-Mazzer Formation of late Viséan age and the Mouizeb el Atchane Member of middle early Serpukhovian age. The occurrence in the Ain Mezerelt Member of earliest Serpukhovian age fills part of the gap between the earlier reported oc- currences. Koryschisma is known from the Kinderhookian (early Tournaisian) part of the Lodgepole Formation, Montana, and the Osagean (late Tournaisian) Lake Valley Formation, New Mexico, in western North America (Sprinkle and Gutschick, 1990). Its occur- rence in the late Viséan and early Serpukhovian of northern Africa reflects migration into the western Te- thys during the Early Mississippian. Material.—Three specimens: RGM 361 150 (llus- trated), RGM 361 151, and RGM 361 152 from the Ain Mezerelt Member, E] Guelmouna Formation, Mis- sissippian (Serpukhovian, El, Pareyn, 1961), at Moui- zeb Reouten, Legrand-Blain collection. Class CRINOIDEA J. S. Miller, 1821 Subclass CAMERATA Wachsmuth and Springer, 1885 Order DIPLOBATHRIDA Moore and Laudon, 1943 Superfamily RHODOCRINITACEA Roemer, 1855 Family RHODOCRINITIDAE Roemer, 1855 Genus RHODOCRINITES J. S. Miller, 1821 Rhodocrinites sp. Plate 1, figures 1-3. Description.—Theca globose, exposed length 15 mm, width 21 mm, widest at distal ends of first pri- mibrachial, walls slightly inclined distally, rounded stellate ornament, ray ridges not present, deep apical pits, all plates very tumid. Infrabasals confined to deep basal concavity, not exposed. Basals 5, large, hexag- onal, length 5 mm (estimated), width 4.9 mm, form base of cup, recurved, proximal end in basal concavity, distal ends upflared. Radials 5, septagonal, equidimen- sional 4.9 mm, outflared. Primanal in line of radials; anal series 1-3-4-2+-". Interray series begins in line of radials; series |-2-3-3-?. First primibrachial hexag- onal. Second primibrachial pentagonal, axillary, iso- tomous branching. Stem circular in transverse section, heteromorphic; noditaxis N3231323 minimal. Colum- nals short, symplectial articulation; latus convex; lu- men pentalobate. Remarks.—The globose shape of the specimen sug- gests that it may represent a new species. It is one of the few forms with deep apical pits, such as the trun- cate-cone shaped Rhodocrinites kirbyi (Wachsmuth and Springer, 1889) and Rhodocrinites sp. (Arendt, 2002, pl. 1, fig. 1), the latter also of Serpukhovian age. The specimen is well preserved but lacks the free arms. The distal base of the fixed arms, tegmen, and anal opening are not exposed, precluding its use as a holotype. Webster (1997) noted that Rhodocrinites, which reached its acme during the Osagean of North America and late Tournaisian of Europe, is in need of review. Material.—One specimen RGM 361 153, Ain Mez- erelt Member, El] Guelmouna Formation, Mississippian CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 19 (Serpukhovian, El), at Mouizeb Reouten, Pareyn col- lection. Order MONOBATHRIDA Moore and Laudon, 1943 Suborder COMPSOCRININA Ubaghs in Moore and Teichert, 1978 Superfamily PERIECHOCRINACEA Bronn, 1849 Family PARAGARICOCRINIDAE Moore and Laudon, 1942 Genus MEGALIOCRINUS Moore and Laudon, 1942 Megaliocrinus? sp. Plate 1, figure 13 Amphoracrinus nov. sp. A Pareyn, 1961, p. 76. Description.—Partial theca with calyx plates poorly preserved, numerous ungrouped arm openings, and numerous bulbous tegmen plates leading to terminal large central plate. Remarks.—The cup is not preserved and the tegmen is crushed inward on the opposite side. The preserved part of the specimen is similar to Megaliocrinus apla- tus Moore and Laudon (1942) from the Morrowan (Early Pennsylvanian) of North America. The two rows of larger distal tegmen plates below the terminal plates on this specimen, however, distinguish it from M. aplatus. Provisionally this extends the range of the genus downward into the Mississippian. The genus is also known from the Early Pennsylvanian (Bashkirian) of Spain (Strimple, 1976). Material.—One partial theca (RGM 361 175) from the Mississippian (Serpukhovian, E2; Pareyn, 1961) Mouizeb el Atchane Member of the Ain el Mizab For- mation, at Mader el Mahjib, synclinal bed 14, Pareyn collection. Family AMPHORACRINIDAE Bather, 1899 Emended diagnosis.—Actinocrinoid-like crinoids possessing five large oral plates at the tegmen summit, having the anal opening on a short anal tube or obliquely oriented beneath the large posterior oral plate, and commonly with meshwork ornamenation on calyx plates. Remarks.—The families Amphoracrinidae and Ac- tinocrinitidae are in need of systematic reevaluation. Currently, the Family Amphoracrinidae contains three genera: Amphoracrinus, Ectocrinus, and Pimlicocri- nus. The main features that distinguish Pimlicocrinus from the other two genera are an extremely low calyx to tegmen length ratio (as opposed to longer calyx to tegmen length ratios in the other genera), the absence of five large oral plates at the tegmen summit (as op- posed to presence of five large orals at the summits of the tegmens in the other genera), and the presence of a central to subcentral anal opening at the tegmen sum- mit (as opposed to an anal opening at the end of a laterally directed anal tube positioned beneath the large posterior oral plate in the other genera). We consider that Pimlicocrinus is more closely re- lated to actinocrinitids than to amphoracrinids. Be- cause the arms are grouped rather strongly on our specimens of Pimlicocrinus, which also is the case for the specimens of Pimlicocrinus figured by Wright (1955), and following the classificatory key to subfam- ilies and genera of the Actinocrinitidae presented in Webster and Lane (1987), we here remove Pimlico- crinus from the Amphoracrinidae and place it within the Subfamily Actinocrinitinae, Family Actinocriniti- dae. In addition to Amphoracrinus and Ectocrinus, two genera that were erected since publication of the Trea- tise (Moore and Teichert, 1978), Ancalocrinus and Displodocrinus Webster and Lane (1987) possess large spinose orals at the tegmen summit and an obliquely directed anal opening. Ancalocrinus was placed in the family Actinocrinitidae and Displodocrinus was placed in the Sunwaptacrinidae. Based on their shared characters with the two other genera of amphoracrin- ids, however, we here remove Ancalocrinus from the Family Actinocrinitidae and Displodocrinus from the Family Sunwaptacrinidae and place them both within the Family Amphoracrinidae. These changes in the family Amphoracrinidae now restrict its range to the Mississippian (Tournaisian, Viséan, and Serpukhovian) of North America, Europe, southwest China, and North Africa. Genus ECTOCRINUS Wright, 1955 Remarks.—Wright (1955) discussed the early rec- ognition of Amphoracrinus, noted the previous rec- ognition of A. gilbertsoni (Miller in Phillips, 1836) as the type species by Wachsmuth and Springer (1897), established the neotype for A. gilbertsoni, and erected Ectocrinus. Although he did not specify the generic differences between the two genera, his description of Ectocrinus mentions that the tegmen has very steep or concave sides and the cup has a more inflated bowl shape. All three species that Wright (1955) assigned to Ectocrinus (E. olla, E. expansus, and E. macneanensis) are distinguished from Amphoracrinus by the concave sides of the tegmen, a more inflated cup, and the pres- ence of five very large orals with projecting transverse ridges at the summit of the tegmen. The extreme de- velopment of the orals (large blade-like transverse pro- trusions ending in three short rounded nodes) also oc- curs on A. anthodeus Chen and Yao (1993), which we 20 BULLETIN assign to Ectocrinus. One could argue that the mor- phologic differences between Amphoracrinus and Ec- tocrinus are insignificant for generic recognition be- cause Amphoracrinus also has 5 large orals at the sum- mit. In Amphoracrinus, however, the orals tend to be smaller, commonly are very bulbous or have rounded protrusions, and lack the transverse ridge. Currently the 17 species assigned to Amphoracrinus (Bassler and Moodey, 1943; Wright, 1955; Webster and Lane, 1987; Chen and Yao, 1993) are known from northwestern Europe, North America, and China. Ectocrinus prob- ably evolved from Amphoracrinus by modification of the orals and, including those below, currently has sev- en species assigned to it from England, Ireland, Mo- rocco, Algeria, and China. Ectocrinus rouchi (Delpey, 1941), new combination Plate 1, figures 4—12 Amphoracrinus rouchi Delpey, 1941, p. 217, figs. 4-8. Termier and Termier, 1950, p. 83, pl. 208, figs. 37-41; Webster, 1973, p. 51. =) Description.—Theca turbinate, tegmen shorter than calyx, all plates with fine anastomosing ridge ornament forming irregular meshwork pattern, sutures im- pressed, pentalobate in oral view, may be slightly wid- er on posterior. Calyx medium high to wide bowl- shaped, sides weakly convex, base truncated for stem attachment. Basal circlet formed by 3 subequal plates, proximally horizontal, distally upflared at approxi- mately 50°, visible in lateral view. Radials 5, hexag- onal (A, C, and D) or septagonal (B and E) if adjoining 2 basals, slightly wider than long to equidimensional, outflared at approximately 50°, straight to slightly con- vex longitudinally, gently convex transversely. Radial facet plenary. Primanal hexagonal, slightly longer than wide, slightly smaller than radials, in line with radials; anitaxis |-2-3-3-tegmen. Primibrachials 2; first primi- brachial hexagonal, widening to base shoulder facets; second primibrachial pentagonal, axillary, much wider than long, straight to gently convex longitudinally; both primibrachials gently convex transversely, upflar- ing more steeply than radials. First and second secun- dibrachials fixed; second secundibrachials biserial, arms free above. Ambulacral openings 2 per ray, elon- gate, separated by narrow elongate ambulacral plate adjoining two central mutually adjacent second secun- dibrachials. Tegmen highly inflated, sides slightly con- cave, capped by 5 large orals, summit concave, plates slightly to moderately bulbous. Posterior oral largest, adjoining other 4 in a semicircle. Orals bear upward- flared sharply angular transverse ridge along midline, commonly lost by breakage. Ambulacral plates adja- cent and above openings small, numerous, irregular, grade into slightly larger plates below large orals. In- 368 Table 2.—Measurements in mm for Ectocrinus rouchi n. comb. Spec. no. (RGM) 361 154 361 155 361 156 Thecal length 37.8 32 45 Thecal width 30.4 30.2 38 (max.) Diameter basal circlet 12 9:3 13 Basal length 6.1 4.5 6.4 Basal width 9.0 6.9 10 Radial length 7.8 6 8.4 Radial width 10.1 3} 0.5 Primanal length 8.2 6 9.6 Primanal width thes) 5.6 9.0 First primibrach length 5.4 3:1 6.4 First primibrach width 8.0 6.7 8.2 Second primibrach length 4.5 4 5:3 Second primibrach width des} 6.5 7.3 Anal oral length 6.2 (approx.) 5.9 eh Anal oral width 9.3 (approx.) 8.4 95 Diameter stem facet 6.6 6.8 6.6 terambulacral plates of intermediate size, irregular up to large orals. Anal opening on distal side of anal tube formed of small irregular plates, directed upward in- side rounded lip terminating tube. Transverse medial ridge on posterior oral forms shield above anal open- ing. Stem facet round, slightly impressed, crenularium very narrow along wide areola, axial canal broadly pentalobate. Distal arms and stem unknown. Measure- ments given in Table 2. Remarks.—Ectocrinus rouchi (Delpey, 1941) was described from upper Viséan strata of Morocco. The original figures (Delpey, 1941, unnumbered plate figs. 4-8) are line sketches and show a fine granular orna- ment. Delpey (1941, p. 217), however, described the ornament as “‘Lornementation des plaques est guillo- chée, souvent avec un centre, mais ne forme jamais d’étoile,” which we interpret as ““The ornamentation is a window-like meshwork, often with a center, but without radiating ridges.” This is a meshwork orna- ment which is present on Amphoracrinus gilbertsoni (Miller in Phillips, 1836) as illustrated by Wright (1955, pl. 49, figs. 12, 13) and on Ectocrinus olla (M°Coy, 1851) as illustrated by Wright (1955, pl. 52, figs. 1, 10). Ectocrinus rouchi has a considerably lon- ger vase-shaped cup than the Irish species E. macne- anensis Wright (1955) or the two English species, E. olla and E. expansus Wright (1955), all of which have relatively shorter more globose-shaped cups. Most specimens of E. rouchi are slightly to mod- erately distorted and part of the theca may be lost by weathering. Variation in shape of the primibrachials is particularly noteworthy among these specimens (Table 3). In addition, rarely there is a single axillary primi- brachial in one ray (RGM 361 156). Abnormalities are noted on two specimens. Specimen RGM 361 154 has CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 21 Table 3.—Number of sides of primibrachial plates of Ectocrinus rouchi. Axillary primibrachials followed by capital A. Spec. no. (RGM) A ray B ray C ray D ray E ray 361 154 6 6 6 6 4 361 155 ? 6 5 6 ? 361 156 4 4 6A 4 4 361 157 6 5 6 2 B 361 158 5 4 4 a ? 361 159 6 6 ? ? 4 361 160 6 6 6 ? 6 361 161 6 5 6 ? ? 361 162 6 6 6 6 ? an abnormal E ray. It appears to have been damaged and in the process of regeneration of the proximal se- cundibrachials at the time of death or it was not re- generated (PI. 1, fig. 5). Specimen RGM 361 157 has aberrant growth with extreme shortening of the D ray in the tegmen, which resulted in arm openings very high on the tegmen (PI. 1, fig. 11). This is interpreted as the living organism having grown against an un- known object and the arm openings were unable to become free at the normal position. Specimen RGM 361 163—rays uncertain, one pri- mibrachial quadrangular, one pentagonal, one hexag- onal, others unknown. Specimen RGM 361 164—specimen too fractured, rays uncertain. Material.—Eleven specimens: Four figured speci- mens RGM 361 154, RGM 361 155, RGM 361 157, and RGM 361 158 and seven unfigured specimens RGM 361 156, and RGM 361 159 through RGM 361 164, all from the undifferentiated Akacha and Mazzer formations (Pareyn, 1961), at Couverture au Djebel loucha of late Viséan, very late Pl (Pareyn, 1961); Pareyn Collection. Specimens RGM 361 154-RGM 361 156 and RGM 361 158 are from a slightly lower stratigraphic level than all others. Ectocrinus mezereltensis, new species Plate 2, figures 1-12; Plate 3, figures 7-14 Diagnosis.—Distinguished by one or more of the following features: tegmen approximately equal to ca- lyx length but variable, tegmen with slightly convex to mostly concave sides, coarser nodose to anasto- mosing ornament, or narrower transverse ridges on five large orals. Description.—TVheca turbinate, tegmen approxi- mately same length as calyx varying from slightly less to a little greater length, all plates with coarse granu- lose to anastomosing ridge ornament, pentalobate in oral view, widest on posterior. Calyx wide bowl- shaped, sides vary from slightly concave to straight to weakly convex, base truncated for stem attachment. Basal circlet tripartite, formed by 3 subequal plates, proximally horizontal, distally outflared, visible in lat- eral view. Radials 5, hexagonal (A, C, and D) or hep- tagonal (B and E) if adjoining 2 basals, slightly wider than long to equidimensional, outflared at approxi- mately 45°, straight to slightly concave longitudinally, gently convex transversely. Radial facet plenary. Pri- manal hexagonal, slightly longer than wide, slightly smaller than radials, in line with radials; anitaxis 1-2- 3-4-tegmen. Primibrachials 2; first primibrachial quad- rate, pentagonal, or hexagonal widening to base shoul- der facets, shape dependent on contacts with first in- terprimibrachials, quadrate none, pentagonal 1, hex- agonal 2; proximal and distal sutures convex outward giving pseudohexagonal or puffy quadrate form; sec- ond primibrachial pentagonal, axillary, wider than long, straight to gently convex longitudinally, moder- ately convex transversely, outflaring at same angle as radials to more upflaring. First secundibrachial fixed; second secundibrachials biserial, arms free above. Am- bulacral openings 2 per ray, elongate, separated by narrow elongate ambulacral plate adjoining 2 central mutually adjacent second secundibrachials. Tegmen highly inflated, sides slightly concave to slightly con- vex, capped by 5 large orals. Posterior oral largest ad- joined by all others. Orals bear upward-flared trans- verse ridge slightly distal of midline, often lost by breakage. Ambulacral plates adjacent and above am- bulacral openings small, numerous, irregular up to large central plate followed by 2 rows of intermediate size interlocking staggered plates up to large orals. In- terambulacral plates of intermediate size, irregular up to large orals. Anal opening on protruded interambu- lacral series of small plates, directed laterally or obliquely upward. Stem transversely round, hetero- morphic proximally; noditaxis NI minimal. Columnals very short, latus angular or rounded; crenularium very narrow along wide areola; lumen large, broadly pen- talobate. Distal arms and stem unknown. Measure- ments given in Table 4. Remarks.—Ectocrinus mezereltensis n. sp. differs from E. rouchi by having nodose to anastomosing or- nament that is coarser than that of any of the three species recognized by Wright (1955). The transverse ridge of E. mezereltensis 1s much smaller than the plate-like protrusions on E. anthodeus (Chen and Yao, 1993). Variation is noted in the relative length of the teg- men, width of the posterior interray, number and ar- rangement of the ambulacral plates, relative size of plates immediately below the orals, and concavity of the tegmen summit of E. mezereltensis. As in E. rou- chi, considerable variation occurs in the shape of the Table 4.—Measurements in mm for Ectocrinus mezereltensis n. sp. BULLETIN 368 Type Holotype Paratype | Paratype 2 Paratype 3 Spec. No. (RGM) 361 165 361 166 361 167 361 168 Thecal length 37.4 20.9 28.7 35:5 Thecal width (maximum) 40.3 20 26.6 325 Diameter basal circlet 10.1 By 8 10.5 Basal length 5.6 333) 4 S) Basal width 8.1 5 6.7 7.6 Radial length 7 3. 4.3 6.0 Radial width 8.6 5.4 6.4 3.2 Primanal length 6.7 3.6 Sil 6.1 Primanal width 6.1 3:3 4.5 6.1 First primibrachial length 6.8 2 3.6 4.5 First primibrachial width 7.6 4.1 5.5 Gh) Second primibrachial length 2:3 2.6 ») 5 Second primibrachial width 4.5 6.6 8.5 Thee) Anal oral length ie B) 4.9 7.5 Anal oral width 8.5 525 eS 7.4 Diameter proximal columnal 3.5 5) 6.5 first primibrachials of E. mezereltensis (Table 5) and rarely there is an axillary single primibrachial in one ray. Material.—Nine specimens: Holotype RGM 361 165, six paratypes RGM 361 166—RGM 361 171, and two mentioned specimens (RGM 361 172, RGM 361 173). All specimens from the Ain Mezerelt Member, El Guelmouna Formation, Mississippian (early Ser- pukhovian, El; Pareyn, 1961), at Mouizeb Reouien; Pareyn collection. Etymology.—Named for the Ain Mezerelt Forma- tion. Ectocrinus redactus, new species Plate 3, figures 1—4 Diagnosis.—Distinguished by having most rays with single primibrachial axillary, relatively shorter calyx length, and the loss of intermediate-size plates between the small ambulacrals and the larger distal Table 5.—Number of sides of primibrachial plates of Ectocrinus mezereltensis. Axillary primibrachials followed by capital A. Spec. no. (RGM) A ray B ray C ray D ray E ray 361 165 6 6 6 6 7A 361 167 4 4 5 5 5 361 168 3) 5 6 6 5 361 169 4 4 5 4 4 361 170 6 6 6 6 5 361 171 6 6 5 6 LN 361 172 6 6 6 6 6 361 173 5 ee ? 5 4 ambulacrals below the large orals at the tegmen sum- mit. Description.—Theca turbinate, length 21.6 mm, width 21.3 mm, tegmen approximately same length as calyx, all plates with medium granulose to anastomos- ing ridge ornament, pentalobate in oral view. Calyx wide bowl-shaped, length 10.4 mm, width 18.5 mm, sides vary from slightly concave to weakly convex, base truncated for stem attachment. Basal circlet tri- partite, diameter 7.8 mm, formed by 3 subequal plates, proximally horizontal, distally outflared, visible in lat- eral view. Radials 5, hexagonal (A, C, and D) or hep- tagonal (B and E) if adjoining 2 basals, wider (7.3 mm) than long (5.2 mm) to equidimensional, A ray widest, narrower toward anal, outflared at approxi- mately 45°, straight to slightly concave longitudinally, gently convex transversely. Radial facet plenary. Pri- manal hexagonal, slightly longer than wide, slightly smaller than radials, in line with radials; anitaxis 1-2- 3-tegmen. Single primibrachial axillary, hexagonal or heptagonal, shape dependent on contacts with second interprimibrachials; C ray with 2 primibrachials, first pentagonal, axillary second hexagonal. Interprimibra- chials large, series 1—2-tegmen. Secundibrachials 2, fixed; arms free above. Ambulacral openings 2 per ray, elongate, separated by narrow elongate ambulacral plate adjoining two central mutually adjacent second secundibrachials. Tegmen highly inflated, sides slight- ly concave to slightly convex, capped by 5 large orals. Posterior oral largest adjoined by all others. Orals bear upward-flared transverse ridge distal of midline, com- monly lost by breakage. Ambulacral plates adjacent CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 23 and above ambulacral openings small, numerous, 11- regular up to large central plate followed by single larger plate below large orals. Interambulacral plates of intermediate size, 2 rows interlocking up to large orals. Anal opening on protruded interambulacral se- ries of small plates, directed obliquely upward, incom- plete. Stem facet transversely round, diameter 4.5 mm, crenularium very narrow along wide areola; lumen large, broadly pentalobate. Distal arms and stem un- known. Remarks.—Ectocrinus redactus n. sp. was derived from E. rouchi or E. mezereltensis by reduction of the primibrachials to a single axillary primibrachial in most rays. As noted in the descriptions, both E. rouchi and E. mezereltensis have considerable variability in the number of primibrachials (mostly two, but some- times one), and EF. redactus approaches the condition of a single primibrachial in all rays. Perhaps more im- portant is the loss of intermediate-size plates between the small ambulacrals and the larger distal ambulacrals below the large orals at the tegmen summit of E. re- dactus. This results in E. redactus having a relatively shorter calyx length. Second secundibrachials of the holotype are lost by weathering or breakage on all rays, but facets for their attachment to the tegmen plates are present on the plates along the sides of the ambulacral openings. The narrow intersecundibrachial plate is preserved in two rays. Material.—Holotype, RGM 361 174, from the Ain Mezerelt Member, El Guelmouna Formation, Missis- sippian (early Serpukhovian, E1), at Mouizeb Reouten; Pareyn collection. Etymology.—redactus, Latin, meaning reduced, which refers to the reduced number of primibrachials. Ectocrinus? sp. Plate 3, figures 5, 6 Remarks.—A fragmentary infrabasal circlet (two large, one small infrabasal plates) and partial basal cir- clet with three columnals has very fine granular to ver- miform ornament. It is questionably assigned to Ec- tocrinus, lacking the proximal arm plates and tegmen needed for unquestioned generic assignment. Material.—Figured specimen (RGM 361 350) from the El Harrada Member, Ain el Mizab Formation, Mis- sissippian (Serpukhovian, El), Cirque de Tagnana (Oued Narkla); Pareyn collection. Family ACTINOCRINITIDAE Austin and Austin, 1842 Subfamily ACTINOCRINITINAE Ubaghs in Moore and Teichert, 1978 Genus ACTINOCRINITES J. S. Miller, 1821 Remarks.—The stratigraphic range of Actinocrinites is Middle Devonian to Permian (Webster, 2003). The acme of the genus is in the Tournaisian, where it is cosmopolitan in the equatorial belt. Discovery of the Algerian Serpukhovian species fills a gap in the pre- viously recognized range. Actinocrinites is currently unknown in the Pennsylvanian and known only from the Permian of Timor and Australia. Actinocrinites becharensis, new species Plate 3, figures 17—20 Diagnosis.—Distinguished by the combination of cup equal to tegmen length, lesser degree of arm pro- trusion, smaller number of arms, and enlarged bulbous ornament on proximal half of radials. Description.—Theca turbinate, length 34.1 mm (in- complete), width 32.6 mm; calyx medium _ bowIl- shaped, length 15.9 mm, width 17.5 mm; tegmen con- ical with slightly excentric anal tube; fixed arms grouped, brachial lobes protruded; pentalobate in oral view; strongly inflated along E ray from base of cup to tegmen summit. Basal circlet 8.2 mm diameter, formed of 3 subequal plates with stem facet impression proximally surrounded by basal flange, distally upfla- red with tips projecting slightly beyond basal flange. Radials 5, hexagonal in contact with 2 basals (B and E), pentagonal in contact with | basal (A, C, and D), upflared, wider than long; radial facet plenary, concave exterior suture. Primanal hexagonal, equidimensional (4.7 mm), in line of radials; anitaxis |-2-3-3-3-tegmen plates. First primibrachial hexagonal where in contact with 2 interprimibrachials, pentagonal where in contact with | interprimibrachial (C ray only), length 4.7 mm, width 7 mm, gently convex longitudinally and trans- versely. Second primibrachial axillary, heptagonal, length 5.3 mm, width 5.8 mm. Axillary secundibra- chial heptagonal or octagonal. Two tertibrachials fixed, arms free above, second tertibrachial on outer half of ray axillary. Arms flare with first secundibrachial, 6 arms per ray where free. Interprimibrachial series |-2- 3-3-tegmen plates. Intersecundibrachial series 1—2-teg- men plates. Intertertibrachial series 1-1-2- or 1-2-2- tegmen plates. Tegmen plates medium size, with cen- tral node irregularly along center of ambulacral plates. Interambulacral plates lack nodes. Ornament on cup plates enlarged bulbous area on proximal half of radial leading to broadly rounded ray ridges extending onto tertibrachials. Finer ornament of anastomosing ridges on cup and tegmen plates, most strongly developed at top cup to base tegmen. Anal tube excentric, incom- plete, extending at least 4.4 mm above tegmen summit. Stem facet round in outline, 6.2 mm diameter, axial canal pentalobate. Distal arms and stem not preserved. Remarks.—Late Tournaisian and Viséan species of Actinocrinites have relatively long cups, most consid- erably longer than the tegmen, giving the specimen a 24 BULLETIN 368 long turbinate appearance with straight to concave cup walls; the arms are strongly grouped and widely pro- truded; and the ornament varies from rounded nodose to coarse nodose to ray ridge. These contrast markedly to the inflated convex walls, cup length equal to teg- men length, and less protruded bunched arms of A. becharensis n. sp. Material.—Holotype, RGM 361 176, is from the Ain Mezerelt Member, E] Guelmouna Formation, Mis- sissippian (early Serpukhovian, El; Pareyn, 1961), from Mouizeb Reouien; Pareyn collection. Etymology.—tThe species name refers to the region in which the specimen was found. Actinocrinites combinatus, new species Plate 4, figures 6—9 Diagnosis.—Distinguished by one or a combination of some of the following features: cup equal to tegmen length, strongly protruded grouped arms, eight arms at thecal rim, and elongated nodose ornament. Description.—Theca_ spindle-shaped, length 21.7 mm (incomplete), width 30.3) mm; calyx medium bowl-shaped, length 15.4 mm, width 23.3 mm; tegmen inverted medium bowl shape, excentric anal tube of unknown length; fixed arms grouped, brachial lobes strongly protruded; pentalobate in oral view. Calyx or- nament coarse nodes elongated to form ray ridges from base radials onto tertibrachials, inverted V ridges from base radials to first interprimibrachials, and flange around proximal edge of basal circlet. Basal circlet 6.6 mm diameter, formed of 3 subequal plates with hori- zontal? stem facet proximally, distally upflared with tips not visible in lateral view obscured by flange on radials. Radials 5, hexagonal in contact with 2 basals (B and E), pentagonal in contact with | basal (A, C, and D), upflared, wider (6.1 mm) than long (4.3 mm); radial facet plenary, concave exterior suture. Primanal hexagonal, slightly longer (4.4 mm) than wide (4.1 mm), in line of radials; anitaxis|]-2-3-5-3-tegmen plates. First primibrachial hexagonal where in contact with 2 interprimibrachials. pentagonal where in contact with | interprimibrachial, quadrangular if not in con- tact with interprimibrachials, length 4.6 mm, width 6.3 mm, strongly convex longitudinally and transversely. Second primibrachial axillary, pentagonal, hexagonal or heptagonal depending on contacts with interprimi- brachials, length 4.7 mm, width 6 mm. Axillary se- cundibrachial pentagonal or hexagonal depending on contacts with primibrachials, flares outward. Tertibra- chials 2 or 3, second tertibrachial on outer half ray axillary, third tertibrachial axillary on inner half ray. Arms flare with first secundibrachial, 8 arms per ray where free. Interprimibrachial series 1-2-2-3 or 4-teg- men plates. Tegmen plates small, numerous, tumid or with coarse central node. Anal tube excentric, extend- ing above tegmen summit unknown distance. Proximal columnals round in transverse section, 5.2 mm diam- eter, heteromorphic, noditaxis NI minimal. Columnals with roundly convex latus, subpentagonal lumen, sym- plectial articulation. Axial canal pentalobate. Distal arms and stem not preserved. Remarks.—The calyx ornament and number of arms at the thecal rim distinguishes Actinocrinites bechar- ensis N. Sp. (SIX arms per ray at tegmen ring) from A. combinatus n. sp. (much coarser cup ornament and eight arms per ray at tegmen ring). Both A. bechar- ensis and A. combinatus may have evolved from a form similar to A. subpulchellus Miller and Gurley (1896), an Osagean form from the Burlington Lime- stone of lowa. The ornamentation is similar to that of A. becharensis n. sp., but the calyx of A. subpulchellus has the elongate appearance of most late Tournaisian and Viséan actinocrinitids. Material.—Holotype, RGM 361 177 from the Ain Mezerelt Member, El Guelmouna Formation, Missis- sippian (early Serpukhovian, El), at Moutzeb Reouten; Pareyn collection. Etymology.—From the Latin combino referring to the combination of morphologic characters which dis- tinguish the species. Genus AACOCRINUS Bowsher, 1955 Aacocrinus algeriaensis, new species Plate 4, figures 1—5 Diagnosis.—Distinguished by the combinaion of a medium bowl-shaped calyx, four arms per ray at thecal rim, reduced fixed interbrachials, and longer tegmen. Description.—Calyx medium bowl-shaped, wider than high to nearly equidimensional, pentalobate in oral view, walls convex, brachial lobes sharply ex- tended in lateral view, flaring out on axillary secun- dibrachials, widely flared with tertibrachials, 4 arms per ray at thecal rim. Stellate ornamentation aligned along rays with secondary ridges to center of interbra- chials, on all cup plates, extending minimally to prox- imal tertibrachial. Tegmen inflated, plates bulbous. Basals 3, equal in size, sutures nearly ankylosed, form gently upflared base, truncated by circular stem im- pression. Radials 5, hexagonal, wider than long, mod- erately convex transversely and longitudinally, largest plates in calyx. First primibrachial wider than long, quadrangular, rounded sides, moderately convex trans- versely and longitudinally. Primibrachial 2 axillary, pentagonal, wider than long, moderately convex trans- versely, gently convex becoming moderately concave longitudinally. Secundibrachial axillary, heptagonal, wider than long, fixed in brachial lobe, widely out- CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 25 Table 6—Measurements in mm for Aacocrinus algeriaensis n. sp.: Type Holotype Paratype | Paratype 2 Spec. no. (RGM) 361 178 361 169 361 180 Calyx height (less anal tube) ib 7/g2) 15.7 16.2 Calyx width 21.8 NO 20.1 Basal circlet diameter 7s) 5 a Basal length 4.6 2 35 Basal width 5.4 4 (est.) 4.9 (est.) Radial length 5.8 4.2 39 Radial width 7.2 Si 6.7 Primibrachial | length See. 2.9 pi) Primibrachial | width 4.9 4.5 4.6 Primibrachial 2 length 24 2.6 2.8 Primibrachial 2 width 5.1 5.2 5.2 Secundibrachial length 2.9 2.4 3 Secundibrachial width 3:2 3 3.6 Primanal length 6 4.1 5 Primanal width 5:2 55) 4.5 Interbrachial length 6.2 5 4.3 Interbrachial width 5.3 4.5 4.3 9) Stem impression diameter flared, convex transversely, concave longitudinally. Outer tertibrachial 1 nearly equidimensional, larger than wider than long inner tertibrachial 1, both fixed in brachial lobe, outflared widely; 4 arms per ray at thecal rim. Primanal narrower and in line with radials, slightly longer than wide. Anitaxis series |-2-3-2, plates longer than wide, decrease in longitudinal con- vexity distally, third series in line with arm lobes. In- terbrachial series 1—2, with interbrachial 2 in line with arm lobes; interbrachial | large, longer than wide, oc- tagonal, widest at apices with primibrachials | and 2, moderately convex transversely and longitudinally. Tegmen strongly arched, plates numerous, 50 to 60, size small to medium, moderate to pronounced central bulbous elevation on each plate. Anal opening pro- truded, surrounded by 7 to 9 small bulbous plates bear- ing facets for higher circlet of plates forming short anal tube. Measurements given in Table 6. Remarks.—There is variation in the relative length of the theca to the tegmen, amount of tegmen arching, and number and arrangement of tegmen plates among the five specimens of Aacocrinus algeriaensis n. sp. Preservation of all specimens is only moderate as weathering processes have etched the surface destroy- ing much of the ornamentation and stem facets. Spec- imens show numerous fractures following rhombohe- dral cleavage planes. Aacocrinus algeriaensis belongs to the lineage of Aacocrinus that has four arms per ray at the thecal rim, such as A. chouteauensis (S.A. Miller, 1891b) or A. tetradactylus Brower, 1967. It is an advanced form of the genus showing reduction of the number of in- terbrachial plates in the theca, from five to three, and a relatively shorter calyx and longer tegmen. This is the youngest known occurrence of Aacocri- nus. It is the first report of the genus from Northern Africa. The genus attained its acme during the Kin- derhookian of North America. It has also been report- ed from the Tournaisian or Viséan of Australia (Web- ster and Jell, 1999a) and the Osagean of North Amer- ica (Brower, 1967; Webster and Lane, 1987). Material.—Five specimens: Holotype, RGM 361 178, and paratypes 1-4, RGM 361 179—RGM 361 182 from the upper part of the Hassi Kerma Formation, Pennsylvanian (middle Bashkirian), at Oglat Hamia; Legrand-Blain collection. Etymology.—Named for Algeria. Aacocrinus algeriaensis? Remarks.—Two globose internal molds show the outlines for the same plate arrangement of the theca as described for Aacocrinus algeriaensis except the an- itaxis is 1-2-4-2. This is probably intraspecific varia- tion. The molds show the four ambulacral tracks merg- ing into two immediately inside the tegmen then con- tinuing along the roof of the tegmen merging toward the mouth at a central junction next to the anus. The anus would have protruded above the mouth, probably as a short anal tube or projection on the tegmen. Un- fortunately the number and arrangement of tegmen plates are unknown. Because of this, plus the lack of all calyx plates to determine ornamentation, the spec- 26 BULLETIN 368 Table 7.—Measurements in mm for Sampsonocrinus cheguigaensis n. sp. Type Holotype Paratype | Paratype 2 Spec. no. (RGM) 361 185 361 186 361 187 Thecal length 15.5 14.4 12.6 Thecal width 23.6 21.2 17.8 Calyx length 9.0 8.1 8.8 Calyx width 17.0 14.2 13°3 Diameter basal circlet 5.0 5.2 4.4 Radial length 3.4 4.1 3.4 Radial width 5.7 BE) 4.5 First primibrachial length Dali 21 1.9 First primibrachial width 5.1 4.6 3:3 Second primibrachial length 2.2 2.0 L.5 Second primibrachial width 3.6 3.5 23) Primanal length 4.6 4 3.4 Primanal width 4.1 3:9 aul Diameter stem impression 3.3 2.0 Dil imens are questionably referred to Aacocrinus alger- iaensis. Material.—Two specimens, RGM 361 183 and RGM 361 184, from the upper part of the Hassi Kerma Formation, Pennsylvanian (middle Bashkirian), at Djebel Béchar; Legrand-Blain collection. Genus SAMPSONOCRINUS Miller and Gurley, 1895 Sampsonocrinus cheguigaensis, new species Plate 5, figures 1-19; Plate 6, figures 1-15 Diagnosis.—Distinguished by flaring with axillary secundibrachial and tegmen formed of many small no- dose plates. Description.—Theca small, globose, arms strongly grouped, protruded, pentalobate in oral view. Cup bowl-shaped, wider than long, sharp multiple ridge stellate ornament of ray ridges, circular rings around radial circlet and primibrachial circlet extending across interprimibrachials, and diagonal ridges from radials across interprimibrachials and anals. Basal circlet flat proximally, distal tips upflared, visible in side view; formed of 3 subequal plates, with thickened ridge sur- rounding stem facet. Radials 5, wider than long, out- flared at 45°, gently convex longitudinally and trans- versely; A, C, and D pentagonal with | suture with basal plate; B and E hexagonal with 2 sutures with 2 basal plates. Primanal longer than wide, gently convex longitudinally and transversely; anitaxis 1-2—3 to 5 (4 most common)-tegmen plates. First primibrachial wid- er than long, quadrangular to hexagonal depending on contacts with interprimibrachials laterally, rarely axil- lary. Axillary second primibrachial wider than long, pentagonal to heptagonal depending on contacts with interprimibrachials on distal shoulders and contact with intersecundibrachial. Axillary secundibrachials wider than long, normally hexagonal adjoining one in- terprimibrachial on both sides, rarely pentagonal not adjoining an interprimibrachial on one side, outflaring. Interprimibrachial series |!—2-variable number of teg- men plates; first interprimibrachial large, approximate- ly equidimensional, hexagonal. Intertertibrachial elon- gate, slender, adjoining 2 tegmen ambulacrals distally. Tegmen moderately arched, plates very tumid, tumid- ity increasing distally; ambulacrals small, numerous at ambulacral opening, increase in size distally; inter- ambulacrals with single large plate in line of thecal rim followed by 3 smaller and then 2 to 4 larger plates distally. Vertically directed anal opening excentric, surrounded by 6 or 7 very tumid to nodose plates. Stem impression circular; facet with wide crenularium, narrow areola, wide pentalobate axial canal. Measure- ments given in Table 7. Remarks.—Variation is noted among the 74 speci- mens of Sampsonocrinus cheguigaensis n. sp. in the amount of inflation of the tegmen from less than half to more than half the thecal length. A predominance of quadrangular and pentagonal primibrachials occurs in the higher cups, whereas hexagonal primibrachials predominate in lower cups as is normal for other spe- cies of Sampsonocrinus. Cups of S. cheguigaensis are rarely composed of primibrachial plates all of one shape. Quadrangular and hexagonal plates do not oc- cur in the same cup. Cup length is controlled primarily by the relative lengths of the first interprimibrachial and first primibrachial plates. Another morphologic feature that may control cup length in some of the actinocrinoids is the position of flaring of the arms, CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 27 which is consistently at the axillary secundibrachials on S. cheguigaensis. In older species of the genus the fixed arms in the cup begin to flare with the axillary primibrachial. The numerous small plates of the teg- men also distinguish S. cheguigaensis from other spe- cies. The axillary first primibrachial occurs in the A ray on specimen RGM 361 196, the B ray on specimen RGM 361 197, and the C ray on specimen RGM 361 193. Because these are collections and not populations it is uncertain if these are abnormal specimens or if they reflect genetic variability within the species. The number of free arms at the tegmen ring varies from four to six. Specimens from Foum ech Cheguiga and Teniet Aissa ben Azzi consistently have six arms, whereas specimens from Chebket Mennouna are var- iable. It is uncertain if the variation is the result of loss by weathering, growth stage, or actual number of free arms at the tegmen ring. Where six arms are present, the fifth and sixth arms are developed along the outer half of each half ray and first appear as small impres- sions of the ambulacral tract in the plates along the sides of the brachial plates. These subordinate ambu- lacral tracts appear to join the main ambulacral tracts above the impression within the axillary brachial. The 48 specimens from north of Chebket Mennouna are not as well preserved as those from Foum ech Che- guiga or Teniet Aissa ben Azzi. Stellate ray ornament on the Foum ech Cheguiga and Teniet Aissa ben Azzi specimens is obvious, whereas that on the Chebket Mennouna is vague on a few, and obliterated on most, specimens. This is interpreted as a taphonomic differ- ence among the three collections. The best preserva- tion of the ornament on the Chebket Mennouna spec- imens is commonly in relatively sheltered areas around the flared brachials, but variation is noted on the de- gree of sharpness of the ornament among the speci- mens. Based on this, the Chebket Mennouna speci- mens apparently remained at the sediment-water inter- face for a greater length of time than those from Foum ech Cheguiga or Teniet Aissa ben Azzi. This is the first report of Sampsonocrinus from the late Bashkirian and the first known from northern Af- rica. The genus previously was reported from the Kin- derhookian and Osagean of North America, late Tour- naisian of England, late Tournaisian and early Viséan of Ireland, and ?Viséan of Australia. The European species have been assigned to a new genus Thinocri- nus by Ausich and Sevastopulo (2001). Material.—Seventy four specimens, all from the Oued el Hamar Formation, Pennsylvanian (late Bash- kirian) in age; Pareyn collection. Holotype, RGM 361 185, Paratypes 1-7, RGM 361 186—RGM 361 192, mentioned specimen RGM 361 193, and two lots (RGM 361 194, 2 specimens; RGM 361 195, 8 spec- imens) from Foum ech Cheguiga. Two mentioned specimens (RGM 361 196, RGM 361 197), three listed specimens (RGM 361 198-RGM 361 200), one fig- ured specimen (RGM 361 201), plus 42 specimens (lot RGM 361 202) are all from north of Chebket Men- nouna. Two specimens (lot RGM 361 203) are from south of Teniet Aissa ben Azzi. Five specimens (RGM 361 204) are probably from Foum ech Cheguiga. Etymology.—tThe species name refers to Foum ech Cheguiga where the type specimens were found. Genus BLAIROCRINUS S.A. Miller, 1891a Remarks.—Blairocrinus is known from North America, represented by a Kinderhookian species (B. trijugis S.A. Miller, 1891a) and an undesignated Osa- gean specimen (B. sp. Lane and Dubar, 1983) and from Japan by a Desmoinesian specimen questionably re- ferred to the genus (B.? sp. Hashimoto, 2001). Lane et al. (1997) reported the genus Blairocrinus from Late Devonian (Famennian) rocks in northwestern China. Waters et al. (2003) reexamined this material and not- ed that the first primibrachials were either pentagonal or hexagonal. In both cases, however, the primibra- chials appeared quadrangular because the pentagonal or hexagonal shape was created by very small trun- cations of the distal corners for contact with interbra- chial plates. Consequently, Waters et al. (2003) placed the specimen in Actinocrinites. This is the first report of the genus from the Early Pennsylvanian. Blairocrinus grafensis, new species Plate 4, figures 13-15 Diagnosis.—Distinguished by a much wider calyx and tumid rather than nodose or spinose tegmen plates. Description.—Theca ovoid, much wider (31.4 mm) than long (19.7 mm), tegmen arched as much above thecal rim as medium bowl-shaped calyx length below rim, pentalobate in oral view. Basal circlet flat, 6.5 mm diameter, formed of 3 subequal plates, not visible in lateral view. Radials 5, wider (7.8 mm) than long (5.5 mm), hexagonal where in contact with | basal or hep- tagonal where in contact with 2 basals, widely out- flared, barely visible in lateral view. Primanal hexag- onal, length 5.9 mm, width 5.1 mm, in line of radials; anitaxis 1-2-3-tegmen plates. Primibrachials 2; first primibrachial quadrangular, wider (6 mm) than long (4.5 mm); second primibrachial axillary, wider (6.9 mm) than long (3.5 mm), hexagonal where in contact with 2 interprimibrachials or heptagonal where in con- tact with 3 interprimibrachials. Secundibrachial axil- lary, wider than long, normally pentagonal, hexagonal if in contact with 3 interbrachials. First tertibrachial on outer half of half ray axillary; second tertibrachial on 28 BULLETIN 368 inner half of half ray nonaxillary. Arms free above second tertibrachial, 8 arms per ray at tegmen ring. Interprimibrachial series |—2-tegmen. Intersecundibra- chial slender, elongate. Tegmen plates tumid; ambu- lacral plates very small and numerous above ambula- cral openings increasing to medium size distally; in- terambulacral plates very small above interprimibra- chials increasing to medium size distally; excentric anal opening on anal tube of indeterminate length at tegmen summit. Axial canal pentalobate. Stem and distal arms unknown. Remarks.—The calyx of Blairocrinus grafensis n. sp. is inflated in the C ray, and the tegmen 1s inflated in the posterior, giving the specimen an asymmetrical, unbalanced appearance. Solution weathering has de- stroyed plate ornament except along the thecal rim. Ambulacral openings of the eight arms at the tegmen ring are preserved only on the D ray. In lateral view the ambulacral openings appear to alternate in size (small-intermediate-small-large) from the outer to in- ner part of the half ray (Plate 4, figure 13). Branching occurs along both sides of the outer arms of each half ray above the secundibrachials. It is unknown if the largest ambulacral opening on the inner arm of the tertibrachials and the intermediate-sized ambulacral opening on the outer part of the same half ray repre- sent the coalesced ambulacral tracts of one or more distal branchings within the free arms leading to these Openings or if they simply are larger than the other arms of that half ray at the tegmen ring. It is also unknown if the size of the openings corresponds to the relative number of distal branchings. The calyx is much wider, and the tegmen is not nodose or spinose and much shorter in B. grafensis than that of the only other species B. trijugis Miller, 1891la, from the Mis- sissippian (Osagean) of North America. Material.—Holotype RGM 361 205 from the upper part of the Hassi Kerma Formation, Pennsylvanian (Bashkirian, R; Pareyn, 1961), from south of Teniet Oum el Graf; Pareyn collection. Etymology.—The species name refers to Teniet Oum el Graf where the specimen was found. Genus PIMLICOCRINUS Wright, 1943 Pimlicocrinus octobrachiatus, new species Plate 7, figures I-11 Diagnosis.—Distinguished by eight arms where free and coarse nodes on distal tegmen plates. Description.—Theca medium size, pear-shaped in lateral view, pentalobate in basal or oral view with strongly grouped arms projecting horizontally; tegmen highly inflated with central anal opening on anal tube of unknown length at summit. Calyx discoid to shal- low, wide bowl shape, all plates strongly inflated with stellate ornament with apical pits. Basal circlet tripar- tite, 3 subequal plates, proximally bearing circular stem facet, horizontal to slightly upflared distally. Ra- dials 5, pentagonal (A, D, C) or hexagonal (B, E), wider than long, subhorizontal to weakly upflared, D radial more equidimensional. Primanal hexagonal, ap- proximately equidimensional, in radial circlet; anal se- ries 1-2-5-tegmen plates. Primibrachials 2; first pri- mibrachial wider than long, rectangular, pentagonal, or hexagonal, may be in contact on distal shoulders with 1 or 2 interprimibrachial plates; second primibrachial wider than long, axillary, pentagonal, hexagonal, or heptagonal, laterally in contact with | or 2 interpri- mibrachials. Tertibrachials | per ray, axillary, wider than long, normally pentagonal, hexagonal if interter- tibrachial present. First quartibrachial nonaxillary in inner half of ray, axillary in outer half of ray. Second quartibrachial axillary in inner half of ray. Arms 8 per ray, projecting horizontally to slightly downflaring, free above branchings on second quartibrachial. Inter- primibrachial plates large, series 1—2-tegmen. Single intertertibrachial not common, very small. Tegmen ta- pers distally; plates increase in size distally, very tumid or with very coarse nodes on all distal plates. Ambu- lacral plates above ambulacral openings small, increas- ing in size distally; ambulacral plates smaller than in- terambulacral plates proximally, forming rounded cov- ering above arm bases. Tegmen summit capped by 6 or 7 larger plates followed by smaller plates forming anal tube. Proximal columnal circular in transverse section, narrow crenularium and areola, wide lumen round, rounded latus. Free arms and distal stem un- known. Measurements given in Table 8. Remarks.—Pimlicocrinus octobrachiatus n. sp. dit- fers from the three English species (Wright, 1955) and the three Chinese species (Chen and Yao, 1993) by having coarser nodes on the distal tegmen plates and eight arms where free. In addition, the shape of the theca differs from that of some of the species. The theca is relatively higher in P. octobrachiatus than in P. latus Wright, 1955. Pimlicocrinus has been reported from the Tournaisian of England (Wright, 1955) and China (Chen and Yao, 1993), Pennsylvanian (Namu- rian and Moscovian) of Spain (Breimer, 1962), and Moscovian of Morocco (fide Breimer, 1962, p. 82). Preservation of the specimens is good to poor. Or- namentation commonly has been modified or de- stroyed, presumably by solution and abrasion process- es. The tips of the fixed arms rarely are preserved be- yond the tertibrachials. Material.—Eight specimens from the Pennsylvanian (upper Bashkirian) Oued el Hamar Formation; Pareyn collection. Holotype (RGM 361 206), paratype 2 CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 29 Table 8—Measurements in mm for Pimlicocrinus octobrachiatus n. sp. Type Holotype Paratype 1 Paratype 2 Spec. no. (RGM) 361 206 361 207 361 208 Thecal length 23 Palle) 26 Thecal width (maximum) 28.7 29.2 35.9 Tegmen length (incomplete) 16.8 13.6 16.4 Diameter basal circlet 6.1 Tes) 7.4 Radial length 3-7 4.1 5.4 Radial width 6.6 6.6 8.2 First primibrachial length 3 3 4.2 First primibrachial width 52D) 6 6.4 Primanal length 4.6 4.8 5.1 Primanal width 4.3 4.8 3) Diameter proximal columnal 4.1 (RGM 361 208), paratype 4 (RGM 361 210), and specimen (RGM 361 211) are from the north flank of Chebket Mennouna. Paratypes | (RGM 361 207) and two specimens (lot RGM 361 212) are from southwest of Djebel Horreit. Paratype 3 (RGM 361 209) is from south of Teniet Aissa ben Azzi. Etymology.—Octobrachiatus, Greek, refers to eight arms where free. Pimlicocrinus sp. Plate 7, figures 18, 19 Description.—Calyx medium size, 23 mm long (in- complete), 26.7 mm wide, pear-shaped in lateral view, pentalobate in basal or oral view with weakly grouped arms. Calyx discoid, subhorizontal, sutures deeply im- pressed, all plates strongly tumid. Basal circlet small, 7.4 mm diameter, subhorizontal, with 1.7 mm circular invagination for stem attachment. Basals 3, subequal, length 3.2 mm, width 4.9 mm. Radials 5, wider (5.9 mm) than long (2.9 mm), hexagonal, slightly elevated above basal circlet; D radial more equidimensional. Primanal in radial circlet, pentagonal, length 3.2 mm, width 3.6 mm; anal series 1-2-5-tegmen. Primibrachi- als 2; first primibrachial hexagonal, second primibra- chial hexagonal or heptagonal depending on number of interray plates in contact. First secundibrachial wid- er than long, nonaxillary. Second secundibrachial wid- er than long, normally nonaxillary, may be axillary in anterior half of D ray. Arms 4 per ray where free, minimum 20 total, project downward slightly at base of free arms. Tegmen highly inflated, tapering distally; all plates bulbous, bearing coarse nodose ornament; ambulacral plates elevated above intervening inter- ambulacral areas. Anal opening probably central at distal end of tegmen, not preserved. Free arms and stem not preserved. Remarks.—There are three small circular borings, each 2 mm diameter, of an unknown organism on the calyx of Pimlicocrinus sp. (Text-fig. 4; Pl. 7, fig. 19). One is at the junction of the D radial, primanal, and basal circlet and may have resulted in deformation of the D radial. The second boring is between the D radial and first primibrachial toward the anal side. A third boring is between the A radial and the first primibra- chial toward the E ray side. All borings are filled with matrix, and it is uncertain if they completely penetrate the plates or not. All are located at plate sutures, one Text-figure 4.—Plate diagram of lower part of calyx of Pimlico- crinus sp. showing location of drill holes. Central stem impression surrounded by tripartite basal circlet. A ray at top. Radials—A through E, primanal—P, drill holes—black circles. 30 BULLETIN 368 a triple junction, and suggest selection of the boring site was made by the boring organism at points of weakness of the calyx. All of these sites were well below the anal opening and made while the crinoid was living. Baumiller (1990) documented gastropod drilling of crinoid tegmens. Although he did not spe- cifically note that the drilling occurred at triple junc- tions, it would appear that most of the drillings he illustrated were situated at plate junctions, mostly tri- ple junctions. Donovan (1991) illustrated a cup of Syn- bathocrinus conicus from the Mississippian of Eng- land with a boring site at a triple junction, which re- sulted in a deformation of the cup. He suggested that this site was located in a protected position, well ele- vated, and up current. We agree that the boring site would have been up current in an elevated position, but it depends upon the living orientation of the cri- noid as to how direct the exposure was within the cur- rent. The calyx lacks parts of A and E rays above the base of the arms and the distal part of the tegmen. Abrasion has obliterated most of the ornament on the cup and the tegmen. The four arms per ray distingish Pimlicocrinus sp. from the eight arms per ray of P. octobrachiatus. This is not thought to be a growth stage difference because comparable and smaller spec- imens of P. octobrachiatus have eight arms per ray. Material.—Figured specimen RGM 290 871 is from the Pennsylvanian (upper Bashkirian) Oued El Hamar Formation, lower member limestone above level ML176 at Mouizeb El Atchane, 300 m north of Beé- char; Winkler Prins collection. Actinocrinitids indeterminate Remarks.—Several specimens of actinocrinitids are similar to Sampsonocrinus, but are incomplete or so poorly preserved that they are unidentifiable with cer- tainty below the family level. They are mentioned for completeness of the fauna. Actinocrinitid indeterminate | Remarks.—Two unfigured weathered thecae (lot RGM 361 213) with nodose tegmen plates similar to those of Sampsonocrinus are from the Oued el Hamar Formation, southwest of Djebel Horreit; Pareyn col- lection. Actinocrinitid indeterminate 2 Plate 4, figure 12 Remarks.—One partial calyx (RGM 361 214) lack- ing the D ray plates and most plates of the thecal rim, possibly belonging to Sampsonocrinus, is from the Chabet Kerkour Formation (= Ain Guettara Member) at Iaouerta, southwest of Djebel Horreit; Pareyn col- lection. Actinocrinitid indeterminate 3 Plate 4, figures 10, 11 Remarks.—One abnormal partial theca, lacking the D ray and anal interray, has a small narrow extra plate in the B ray of the basal circlet, two primibrachials, an axillary secundibrachial, an axillary tertibrachial on the outer half ray, and two nonaxillary tertibrachials on the inner half ray. The arms flare with the axillary second primibrachial and are free above second terti- brachial or first quartibrachical. There are six arms per ray where free and the tegmen plates are all tumid to nodose. The tegmen is approximately the same length as the calyx. It is possibly a Sampsonocrinus. The specimen (RGM 361 251) is from the upper part of the Oued el Hamar Formation, Pennsylvanian (Bash- kirian), at Foum ech Cheguiga; Pareyn collection. Actinocrinitid indeterminate 4 Plate 7, figures 12-17 Remarks.—Five tegmen fragments, perhaps from the same specimen, consist of numerous small vari- able-sized bulbous to blunt-spined polygonal plates. The largest specimen (RGM 361 216) formed less than ¥, of the tegmen and is formed by more than 50 plates. One specimen (RGM 361 220) has several very small elevated ambulacral plates along one edge that are the outflared thecal rim plates immediately above the am- bulacral openings of one ray. Two specimens (RGM 361 216, RGM 361 218) lack the very small ambu- lacral plates, but have the converging smooth ambu- lacra trackways on the interior. Specimen RGM 361 217 has three plates along one edge that bordered the anal opening, which would have been ventrally di- rected and projected as an anal tube of undetermined length. These tegmen fragments are much larger and have higher bulbous to spinous surfaces than those of Aa- cocrinus algeriaensis. The tegmen would have con- tained many more plates than that of A. algeriaensis. Features preserved in these fragments show general morphology common to the aacocrinids and actino- crinids, thus they are conservatively referred to the actinocrinitids. Material.—Five fragmentary specimens, RGM 361 216-RGM 361 220, from the upper part of the Hassi Kerma Formation, Pennsylvanian (Bashkirian), at Djebel Béchar; Legrand-Blain collection. Actinocrinitid? indeterminate 5 Remarks.—One tripartite basal circlet, 3.9 mm long, 9.6 mm diameter, has irregular anastomosing ridge or- CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. nament surrounding the stem facet, has a pentalobate axial canal, and retains the proximal and part of the second columnal. Material.—Basal circlet, RGM 361 221, from the top of the Djenien Formation, Late Mississippian (Ser- pukhovian, E2), at Chebket Djihani; Pareyn collection. Suborder GLYPTOCRININA Moore, 1952 Superfamily PLATYCRINITACEA Austin and Austin, 1842 Family PLATYCRINITIDAE Austin and Austin, 1842 Genus PLATYCRINITES J. S. Miller, 1821 Remarks.—Approximately 175 named species, based on cups and crowns, currently are assigned to Platycrinites (Webster, 2003). All Silurian and most Devonian species assigned to the genus were judged not to belong to Platycrinites but were not reassigned (see Lane et al., 2001). Slightly over 100 species of Platycrinites are of Tournaisian and early Viséan age, with most reported from North America (70 species) and Europe (23 species), followed by China (6 spe- cies), Australia (1 species), and Japan (1 species). Even though some of the North American and Euro- pean Tournaisian and Viséan species are probably syn- onyms, this time interval represents the acme of the genus. During this acme, Platycrinites was a cosmo- politan equatorial-belt taxon occurring between a max- imum of 40° S (Australian block) to 30° N (northern part of the North American block), based on paleo- geographic reconstructions of Scotese and McKerrow (1990). From the late Viséan through the Guadalupian only 14 named species have been reported world wide, with 10 of these between the Mississippian (late Viséan) and Pennsylvanian (late Bashkirian) from North Amer- ica (6 species), Scotland (2 species), Russia (1 spe- cies), and Morocco (1 species). Permian species are known from Canada (1 species), Russia (1 species), Australia (1 species), and Timor (1 species). A number of unnamed species based on cups, crowns, and col- umnals have been reported from this same time inter- val from these same areas. An excellent review of the columnals assigned to Platyplateium Moore and Jef- fords, 1968, and Platycrinites for this time interval was given by Bowsher and Strimple (1986). Species of Platycrinites from Algeria occur in five horizons from the basal part of the Late Mississippian (Serpukhovian) into Pennsylvanian (basal Bashkirian) strata. Thus they provide significant new information about the genus during a time interval when relatively few species are known elsewhere. The species are con- sidered part of an evolutionary lineage that probably evolved from one of the Tournaisian or Viséan taxa of Platycrinites with nodose ornament illustrated by Wright (1956), such as P. granulatus Miller, 1821, and P. striatus Miller, 1821, from Tournaisian strata of Ire- land, or from one of the numerous spinose or nodose species illustrated by Wachsmuth and Springer (1897), such as P. hemisphericus (Meek and Worthen, 1865), P. nodostriatus (Wachsmuth and Springer, 1897), P. pocilliformis (Hall, 1858), P. spinifer (Wachsmuth and Springer, 1897), P. spinifer elongatus (Washsmuth and Springer, 1897), and P. verrucosus (White, 1865), among others, from North America. Nodes, anastomosing coalesced nodes, and ridge or- nament on the cups of Carboniferous species of Pla- tycrinites Show an extreme range of development, in- cluding a few aligned nodes (P. parvinodus (Hall, 1861)), many aligned nodes (P. pocilliformis (Hall, 1858)), many aligned granules (P. ornogranulus (McChesney, 1860)), aligned very coarse nodes to blunt spines (P. verrucosus (White, 1865)), aligned to anastomosing coalesced nodes (P. saffordi (Hall, 1858)), parallel ridges (P. regalis (Hall, 1861)), and more. Several patterns within this wide range of or- nament development are obvious with only a cursory scanning of the specimens. Multiple types of patterns may occur on a single specimen. These patterns in- clude a variety of types at specific locations on the cup that we interpret to represent morphologic develop- ment by the crinoid to thwart platyceratid gastropods or other unwanted organisms from crawling up the stem and across the cup before reaching the base of the arms or the tegmen. Each type is described here, followed by an interpretation for its position. 1. Aligned nodes to ridges around stem attachment: obstruct or discourage organisms from crawling onto the cup. 2. Aligned nodes to ridges radially across the basal circlet from the stem facet to distal edge in interray position: obstruct or discourage organisms from crawl- ing along the interray onto the radials and then onto the tegmen. 3. Aligned nodes to ridges radially across the basal circlet from the stem facet to distal edge in line of ray axes: obstruct organisms from crawling along the ray axes onto the radials and then to the base of the arms. 4. Aligned nodes, ridge, or parallel rows of ridges between stem facet and distal edge or along distal edge of basal circlet: obstruct organisms from crawling onto the radials and thence onto the tegmen or reaching the base of the arms. 5. Aligned nodes to ridges radially along the lateral edges of the radial: obstruct organisms from crawling across the radial to reach the tegmen. 6. Aligned nodes to ridges radially along the axes ee) to of the radial from the proximal edge to the base of the arms: obstruct organisms from crawling across the ra- dial to reach the base of the arms. 7. Aligned nodes, ridge, or parallel rows of ridges along proximal edge to base of arms: obstruct organ- isms from crawling across the radial to reach the base of the arms. 8. Aligned nodes or ridge forming inverted V from base of radial facet to proximal apices of radials: ob- struct organisms from crawling onto the radials and thence onto the tegmen or reaching the base of the arms. This ornament may continue onto the basal cir- clet. 9. Aligned nodes or ridge along proximal side of radial facet: obstruct organisms from obtaining access to tissue of base of arm. 10. Aligned nodes or ridge along distal edge of ra- dials lateral of facet: obstruct organisms crawling across radial onto tegmen. 11. Radially aligned nodes or ridge on first inter- ambulacral: obstruct organisms crawling across plate onto tegmen. Nodes or short spines on tegmen plates and the de- velopment of anal tubes also are interpreted as obstruc- tions to organisms trying to crawl across and settling on the tegmen. Development of spines on columnals would have been an additional deterent to organisms crawling along or attaching to the stem. Similar node and ridge ornament is found in some of the other gen- era of the platycrinitids, such as Eucladocrinus and Plemnocrinus, and probably served the same purposes. The development of nodose plates and stellate ridge ornament among some genera of the glyptocrinids, melocrinitids, rhodocrinitids, coelocrinids, acrocrinids, batocrinids, and actinocrinitids is considered to have served the same purposes as was node development. Genera within each of these taxonomic groups with platyceratids still attached to the calyx have been re- ported by several authors (Keyes, 1888: Clarke, 1921; Bowsher, 1955a; Yakovlev, 1956, among others). In the Viséan as most of the camerates declined, the pla- tyceratids adapted to living on the cromyocrinids, and continued to do so into the Permian. In the Late Car- boniferous the cromycrinids developed nodose orna- ment similar to that of the more nodose platycrinitids. Platycrinites reouienensis, new species Plate 8, figures 1—8 Diagnosis.—Distinguished from non-Algerian Mis- sissippian and Permian species by the combination of the globose theca, tegmen moderately arched, cup bowl-shaped, basal circlet shallow bowl, walls sub- vertical, radial facets elongate horseshoe-shaped on ra- dial platform, single axillary primibrachial, and anal BULLETIN 368 opening projecting obliquely. Distinguished from other Algerian species by the coarse nodose ornament form- ing an inverted-V pattern from radial facet to basal- radial apices, aligned along lateral sides of radials, and a few irregular nodes along the proximal part of the radials. Description.—Theca globose, medium size, length 13.6 mm (crushed inward and laterally), width 16 mm (average). Cup bowl-shaped, length 10.9 mm, width 16 mm (average), walls subvertical, sutures slightly impressed. Basal circlet shallow bowl, 10.5 mm di- ameter, formed of 3 plates, 2 larger of equal size, smaller in EA interray; proximal tips downflared be- low stem facet in shallow impression or basal concav- ity, distally upflared forming 3.5 mm of cup length; with coarse nodes aligned along interrays and less aligned along distal sides of plates. Radials 5, 8.3 mm long, 8.6 mm wide, widest at distal end of interradial sutures, moderately convex longitudinally and trans- versely; ornamented with coarse nodes forming in- verted V from radial facet to basal-radial apices, aligned along lateral sides of radials, and a few irreg- ular nodes along the proximal part of radials. Radial facet angustary, narrow, elongate, horseshoe-shaped, on slight radial platform, subvertical to slightly upward projecting. Single primibrachial axillary, overlapped laterally by first secundibrachials. Arms unknown, minimum 2 per ray. Tegmen crushed, proximal plates bulbous, distal plates with very coarse nodes; ambu- lacral plates small adjacent to ambulacral openings, distally become larger; interambulacrals with single large plate followed by 3 smaller plates and medium to larger plates distally. Anal opening separated from radials minimally by single row of small plates, may have had short anal tube. Opening projecting obliquely well below radial summit. Stem facet circular, 2 mm diameter, concave. Axial canal weathered, probably pentalobate. Remarks.—The tegmen is crushed, with plates of the anterior side doubled against one another and pro- jected over the AB interray on the holotype (RGM 361 222) of Platycrinites reouienensis n. sp. Before crush- ing, the tegmen would have been moderately arched, approximately half the height of the cup. The cup is only slightly distorted with the A radial extended out- ward. C- and D-ray primibrachials are weathered, and only two are preserved. Small facets on the outer edg- es of the radial facets are for the outer parts of first secundibrachials. A small holdfast is attached to the posterior side of the radial facet of the E radial. The paratype (RGM 361 223) is uncrushed and shows the large tegmen plates of the moderately inflated tegmen but lacks the plates around the anal opening. Although the specimen is abraded and the nodes on the radials CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. are greatly subdued, it still shows the same pattern as that of the holotype. Arrangement of the nodose ornamentation of Pla- tycrinites reouienensis is similar to, but specimens lack the keels present on, P. faberi (Miller, 1889), a Late Mississippian (Meramecian or Chesterian) form from North America. The disarticulated cup plates identified as P. spinifer elongatus Wachsmuth and Springer, 1897, by Termier and Termier (1950) from the Viséan of Morroco may have been the progenitor of the youn- ger Algerian species of Platycrinites described herein. The Moroccan specimens are not considered conspe- cific because they have less spinose tegmen plates, fin- er nodes, and a longer basal circlet than the holotype figured by Wachsmuth and Springer (1897, pl. 67, fig. 7). The Morocco specimens have a longer (i.e., more highly arched) tegmen than the Algerian specimens. Material.—Two specimens: Holotype, RGM 361 222, (CP52.27b) from the Ain Mezerelt Member, El Guelmouna Formation, Mississippian (Serpukhovian, early El), at Moizeb Reouten; Pareyn collection. Para- type. RGM 361 223, from the Ain Mezerelt Member, El Guelmouna Formation, Mississippian (Serpukhov- ian, early El), at El Aouidja; Legrand-Blain collection. Etymology.—Named for the locality where the spec- imen was found, Moizeb Reouien. Platycrinites aouidjaensis, new species Plate 8, figures 20, 21 ?Platycrinus spinifer elongatus (Wachsmuth and Springer, 1897). Termier and Termier, 1950, p. 86, pl. 226, figs. 36—37. Diagnosis.—Distinguished from non-Algerian Mis- sissippian and Permian species by the combination of the globose theca, tegmen flat, cup bowl-shaped, su- tures flush, basal circlet medium bowl, walls subvert- ical, radial facets elongate horseshoe-shaped on radial platform, single axillary primibrachial, and anal open- ing projecting subvertical. Distinguished from other Algerian species by the combination of the irregularly spaced coarse nodose ornament, which may form a poorly developed inverted-V pattern from radial facet to basal-radial apices, a ring of nodes surrrounding the stem facet, and a flat tegmen. Description.—Theca globose, large, length 22.2 mm (distal apex not exposed), width 24.6 mm, pentagonal in basal view. Cup medium bowl-shaped, length 17.7 mm, width 24.6 mm, base truncated for stem attach- ment, distal half of walls subvertical, sutures flush. Basal circlet medium bowl, 16.9 mm diameter, 7.6 mm length, plates fused, proximal tips subhorizontal for stem attachment, distally upflared at approximately 45°; with coarse nodes aligned along midline of inter- rays, ringed around stem facet, and some irregular. Ra- Oo es) dials 5, 6.5 mm long, 8.2 mm wide, widest at distal end of interradial sutures, moderately convex longi- tudinally and transversely; ornamented with coarse nodes irregularly spaced to forming poorly developed inverted Vs radiating from the radial facets to the basal radial apices. Radial facet angustary, narrow, elongate, horseshoe-shaped, on slight radial platform, subverti- cal to slightly upward projecting, laterally bear small facets for ends of first secundibrachials. Arms un- known, minimum 4 per ray. Tegmen flat, one-fourth length of cup, plates large with coarse nodes; ambu- lacral plates small adjacent to ambulacral openings, distally larger; interambulacrals with single large plate followed by 3 smaller (but large) node-bearing plates distally. Inflated anal area affecting subjacent radials, visible in basal view as obvious bulge in CD interray. Anal opening separated from radials minimally by sin- gle row of small plates, on anal tube of indeterminate length; opening projecting subvertical below radial summit near rim of tegmen. Stem facet circular, 4.8 mm diameter, concave areola. Remarks.—The holotype (RGM 361 224) of Pla- tycrinites aouidjaensis n. sp. is well preserved, with matrix covering most of the tegmen. The paratype (RGM 361 225), similarly preserved, has lost the basal circlet and proximal parts of some radials but shows the anal opening. A single radial (RGM 361 226) as- signed to P. aouidjaensis shows the proximal ends of four ambulacral grooves on the interior and retains the triangular-shaped axillary primibrachial and axillary single secundibrachials. The facets for the tertibrachi- als on the outer half of the ray are much smaller than those for the tertibrachials on the inner half of the ray, perhaps implying that the inner ones branch again. If so, there would be six arms per ray. Platycrinites aouidjaensis is distinguished from P. reouienensis by the flat rather than moderately arched tegmen, medium rather than shallow bowl-shaped bas- al circlet, poorly developed inverted-V nodes rather than aligned nodes on the radials, presence of a ring of nodes around the stem facet, and flush sutures. Material.—Three specimens. The holotype (RGM 361 224, measured specimen) is from the Mouizeb el Atchane Member, Ain el Mizab Formation, Mississip- pian (Serpukhovian, E2), from Teniet el Aouidja. The paratype (RGM 361 225) was found between the Djen- ien and E] Guelmouna formations, probably from the Mouizeb el Atchane Member of the Ain el Mizab For- mation, Mississippian (Serpukhovian, E2), from Teniet el Aouidja. A partial radial (RGM 361 226) is from the Mouizeb el Atchane Member of the Ain el Mizab Formation, Mississippian (Serpukhovian, E2), from the ravine at Djenien. All Pareyn collection. 34 BULLETIN 368 Etymology.—Named for the locality where the spec- imens were found, Teniet el Aouidja. Platycrinites djihaniensis, new species Plate 8, figures 14-19 Diagnosis.—Distinguished from non-Algerian Mis- sissippian and Permian species by the combination of the globose calyx, tegmen low flat, cup bowl-shaped, basal circlet shallow bowl, walls subvertical, radial facets elongate horseshoe-shaped on radial platform, single axillary primibrachial, and anal opening pro- jecting obliquely. Distinguished from other Algerian species by the combination of coarse nodose ornament forming inverted V from radial facet to basal-radial apices, aligned nodes along lateral sides of radials, nodes forming an inverted T below the radial facet along the ray axis, and anal opening projecting obliquely. Description.—Theca globose, small, length 14.6 mm, width 16.3 mm, base flat, tegmen low flat, cir- cular in oral view. Cup bowl-shaped, length 19.4 mm, width 16.3 mm, walls subvertical at top, sutures slight- ly impressed. Basal circlet fused, shallow bowl, 11.4 mm diameter, length 3.1 mm, with coarse nodes aligned along interrays, ringing stem facet and forming a T in central part of each ray. Radials 5, 8 mm long, 8.8 mm wide, widest at distal end of interradial su- tures, moderately convex longitudinally and_ trans- versely; ornamented with coarse nodes forming in- verted V from radial facet to basal-radial apices, aligned along lateral sides of radials, and forming an inverted T below the radial facet along the ray axis. Radial facet angustary, narrow, elongate, horseshoe- shaped, upward projecting 20° above horizontal; with single axillary primibrachial overlapped laterally by first secundibrachial. Arms unknown, minimum 2 per ray. Tegmen low, flat topped, plates with very coarse nodes to short spines; ambulacral plates small adjacent to ambulacral openings, distally become larger; inter- ambulacrals with single large plate followed by 2 or 3 smaller plates and larger plates distally. Anal opening separated from radials by single large interambulacral followed by minimum of | row of small plates, may have had short anal tube, with opening projecting ver- tically. Stem facet circular, 2.9 mm diameter, shallowly concave, wide crenularium and areola, pentalobate ax- ial canal. Remarks.—Platycrinites reouienensis, P. aouidjaen- sis, and P. djihaniensis n. sp. are closely related. Pla- tycrinites aouidjaensis and P. djihaniensis probably are derived from P. reouienensis by flattening of the tegmen, increased development of the nodose orna- ment, and slight differences in plate sizes and arrange- ment leading to the anal opening. The radial facets of P. djihaniensis are considerably more upflaring than those of P. reouienensis and P. aouidjaensis, whereas the basal circlet is relatively longer, and the pentagonal outline in oral view is best developed on P. aouid- jaensis. The nodose ornamentation of the tegmen of P. reouienensis, P. aouidjaensis, and P. djihaniensis separates them from the bulbous ornament of the teg- men of P. hamarensis n. sp. Material.—Two specimens: holotype (RGM 361 227) and paratype (RGM 362 228) are from the top of the Djenien Formation, Mississippian (Serpukhov- ian, E2), at Chebket Djihani; Pareyn collection. Etymology.—Named for the locality where the spec- imens were found, Chebket Dyjihani. Platycrinites cf. P. djihaniensis Plate 8, figures 11-13 Remarks.—One fused partial basal circlet, one near- ly complete radial, and two partial radials have the same basic nodose ornamentation pattern as P. djihan- iensis, except the nodes are much more numerous be- tween the interray aligned nodes forming triangles within triangles on the basal circlet and radials, the radial facets are relatively narrower with respect to the width of the radial, and the basal circlet is more up- flaring. These specimens may represent a variant of P. djihaniensis or a different species. Because the tegmen is unknown, all specimens are disarticulated, and most are fragmentary, they are referred to P. djihaniensis. Material.—Four specimens, a partial basal circlet (RGM 361 229), 1 nearly complete (RGM 361 230) and 2 partial radials (RGM 361 231, RGM 361 232), from the top of the Djenien Formation, Mississippian (Serpukhovian, E2), at Chebket Djihani; Pareyn col- lection. Platycrinites hamarensis, new species Plate 9, figures 15-22 Diagnosis.—Distinguished from non-Algerian Mis- sissippian and Permian species by the combination of the globose calyx, tegmen moderately arched, cup bowl-shaped, basal circlet very shallow bowl, walls subvertical, sutures impressed, radial facets wide horseshoe-shaped, single axillary primibrachial, and anal opening projecting obliquely. Distinguished from other Algerian species by the combination of coarse irregular nodose and vermiform ornament. Description.—Theca globose, large, length 17.1 mm, width 19.2 mm, tegmen moderately arched, pen- tagonal in oral view. Cup medium bow]l-shaped, length 8.5 mm, width 15.8 mm, base very shallowly convex, walls subvertical, sutures strongly impressed, plates with broad coarse irregular nodose and vermiform or- nament. Basal circlet fused or tripartite, very shallow CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. bowl, 11.2 mm diameter, length 2.5 mm; base with shallow concavity, distal edges upflared, barely visible in side view; azygous basal in E-A interray. Radials 5, large, 10.1 mm long, 10.4 mm wide, widest at distal end of interradial sutures, gently convex longitudinally and transversely, ornament of low broad nodes. Radial facet angustary, wide, horseshoe-shaped, subvertical. Primibrachial small, axillary, triangular in exterior out- line, moderately convex transversely, with low broad central node. First secundibrachials much wider than long, laterally extending beyond primibrachial to at- tach to radial. Second secundibrachial axillary. Mini- mum 4 arms per ray, free with first secundibrachial. Tegmen plates with very bulbous centers; ambulacral plates small adjacent to ambulacral openings, distally become larger; interambulacrals with single plate fol- lowed by 2 or 3 smaller plates and larger plates dis- tally. Anal interray has single large plate, larger than all other first interambulacrals, followed by 3 smaller plates at base of bulbous anal opening slightly above central tegmen summit. Anal opening projecting obliquely at 45°. Stem facet impressed, circular, small, 3.4 mm diameter, moderately concave. Remarks.—The holotype (RGM 361 233) of Pla- tycrinites hamarensis n. sp. lacks a part of the A radial and a small part of the basal circlet but has the pro- truded anal area. Paratype 1 (RGM 361 234) has a slightly flatter tegmen with more sharply defined or- namentation. Paratype 2 (RGM 361 235) is weathered and has lost part of the anal side of the theca. Paratype 3 (RGM 361 236) is partly embedded in matrix. A fifth specimen (RGM 361 237) is abraded and has a fragment of the basal circlet missing. Platycrinites hamarensis is distinguished from P. reouienensis, P. aouidjaensis, and P. djihaniensis by its impressed sutures, coarse nodose and vermiform ornament, bulbous tegmen plates, and obliquely pro- jecting bulged anal opening. Material.—Five specimens. Holotype (RGM 361 233) and paratypes 1-3 (RGM 361 234—RGM 361 236) from the Oued el Hamar Formation, Pennsylva- nian (late Bashkirian), north flank of Chebket Men- nouna; Pareyn collection. Mentioned specimen (RGM 361 237) is from the Hassi Kerma Formation, Penn- sylvanian (late Bashkirian), at Oglat Hamia; Legrand- Blain collection. Etymology.—Named for the Oued el Hamar For- mation. Platycrinites sp. | Plate 9, figures 23, 24 Remarks.—A single specimen is referred to Platy- crinites sp. 1. The specimen is of moderate size with a flat base, gently arched tegmen, outflaring cup walls, ee) Nn pentagonal in oral view, and has medium-coarse no- dose ornament forming in three to five semi-aligned rows massed along the interray edges of the radials and single spine alignments below the radial facets. It is poorly preserved, and the radial facets and arm ba- ses are not exposed. The combination of the above features allows recognition as a separate form, prob- ably representing a new species. Lacking knowledge of the arms, it is left in open nomenclature and men- tioned for faunal completeness. Material.—Figured specimen (RGM 361 238) from the upper part of the Oued el Hamar Formation, Penn- sylvanian (late Bashkirian), from Foum ech Cheguiga; Pareyn collection. Platycrinites sp. 2 Remarks.—Three partial radials are abraded or weathered, but still retain some nodes and aligned nodes or ridges. They are possibly variants of P. dji- haniensis, but so fragmentary they are considered in- determinate. Material.—Three partial radials (RGM 361 239), all from the top of the Djenien Formation, Mississippian (Serpukhovian, E2), at Chebket Djihani; Pareyn col- lection. Platycrinites sp. 3 Remarks.—Platycrinitid partial radial with primibra- chial and first secundibrachials. Material.—One partial radial (RGM 362 337), from the upper part of the Hassi Kerma Formation, lime- stone below level ML171, Pennsylvanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gul- ly, Béchar; Winkler Prins collection. Platycrinites sp. 4 Plate 8, figures 22, 23; Plate 17, figures 1, 2 Remarks.—A large tripartite basal circlet and a smaller fused basal circlet, both with irregular coarse- ridge ornament, are assigned to Platycrinites. The nearly circular stem facet is on a pedestal slightly be- low the exterior level of the circlet and is bordered by a round-based, narrow impressed trough. The irregular ornament is most prominent around the distal margin of the circlet. The small axial canal is pentalobate. Material.—Two basal circlets (RGM 361 338: RGM 361 339) from the upper part of the Hassi Kerma Formation, limestone below level ML171, Pennsyl- vanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar; Winkler Prins collec- tion. 36 BULLETIN 368 Platycrinites sp. 5 Plate 8, figures 9, 10 Remarks.—Two unornamented platycrinitid twist columnals (from segmented twist stems) with a den- ticulate fulcal ridge splitting into four finer ridges on distal ends (RGM 361 344). Material.—Two columnals (RGM 361 344, RGM 361 351), from the upper part of the Hassi Kerma For- mation, limestone below level ML171, Pennsylvanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar; Winkler Prins collection. Platycrinites? sp. Plate 9, figures 25-27 Description.—Calyx medium size, length 20.7 mm, width 23.4 mm, mushroom-shaped, pentagonal in oral view. Cup bowl-shaped, length 9.5 mm (estimated), width 19.5 mm, base shallowly invaginated, walls nearly vertical. Basal circlet tripartite, subhorizontal, 15.8 mm diameter, distal edges slightly upflaring, bear- ing circular 3.4 mm diameter stem facet. Basals 3, un- equal. Radials 5, considerably wider (10.4 mm) than long (6.5 mm estimated), projecting slightly medially for horseshoe-shaped subvertical angustary radial fac- et, proximally with extended lip for basal-radial suture, internally proximal edges with concave-downward thickening projection to attach to thick distal edges of basals, shoulders extend distally well above radial fac- et. Radial facets deep. Single axillary primibrachial tri- angular exteriorly. Secundibrachials deep, short, strongly convex transversely, gently convex longitu- dinally, minimum of 2 per half ray, bear V-shaped am- bulacral groove. First secundibrachial overlaps primi- brachial to contact radial facet. Arms 10, minimum, project subhorizontally from radials. Tegmen strongly inflated, projecting laterally beyond radials, formed of numerous medium sized bulbous plates bearing coarse nodose ornament. Single interambulacral plate fol- lowed by 3 or 4 plates in tegmen. Anal opening not exposed. Stem facet bears narrow crenularium along outer edge. Remarks.—The specimen is slightly distorted and cup plates are moderately to deeply abraded, especially along the basal-radial sutures. The assignment to Pla- tycrinites is not certain because the anal series is not exposed. The tegmen is similar to that of P. hamar- ensis. Approximately age-equivalent loose radials and basals bearing similar thickenings of the proximal edg- es of the radials and distal edges of the basals are known from the northwestern part of the People’s Re- public of China (Lane er al., 1996). Material.—Figured specimen (RGM 290 857), from the Oued Bel Groun Formation, Moscovian, Bed M1 (Deleau, 1951), from Béchar-Djedid, immediately south of Béchar. Winkler Prins collection. Genus PLEUROCRINUS Austin and Austin, 1843 Emended diagnosis.—A platycrinitid recognized as having five prominent orals, with each of the four smaller orals in contact with the larger central anal oral forming the summit of the tegmen with a variable small number of smaller interambulacral and ambula- cral plates between them and the radials, and an anal opening directed laterally. Remarks.—Genera of the Platycrinitidae commonly are recognized on the position or direction of the anal opening. An exception is Eucladocrinus Meek, 1872, recognized by having two main arm-bearing ramules in each ray. The excentric anal opening on Platycrin- ites is commonly on the side of the tegmen slightly above the radials but may occur much higher on the tegmen, with or without an anal tube. Pleurocrinus was defined on the presence of a laterally directed anal opening. Otherwise, it is indistinguishable from Pla- tycrinites, from which it was derived. The significance of the position of the anal opening, plate structure sur- rounding it, and overall plate structure of the tegmen with respect to the anal opening is uncertain. Perhaps the position of the anal opening on the edge of the tegmen or on an anal tube was an evolutionary or eco- phenotypic morphologic response to avoid being cov- ered by platyceratid gastropods. This suggestion is supported by the absence of drill holes through the tegmen of crinoids with platyceratids positioned above the anal opening and the presence of drill holes through the tegmen with platyceratids attached but not above the anal opening (Lane, 1978; Baumiller, 1990). All anal openings of Platycrinites and Pleurocrinus are excentric but the position between the radials and central linear axis is quite variable, sometimes show- ing variation within a single species. Species assigned to these two genera have a complete gradation from anal openings through the tegmen directly above the radials without intervening small plates, anal openings with small intervening plates, and openings separated from the radials by one or two larger plates with or without small intervening plates, anal openings well above the radials separated from the radials by a series of small to medium plates, to anal openings originating near the radials to well above the radials at the end of a short to lengthy anal tube. Except for one late Viséan species (P. grandis Wright, 1938), all other species currently assignable to Pleurocrinus are known from the Tournaisian and early Viséan of England, Ireland, and North America (Wright, 1956; Brower, 1970; among others) or the Permian of Timor (Wanner, 1916, 1937). CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 2i7/ Review of the nearly 200 species currently assigned to Platycrinites and Pleurocrinus is beyond the scope of this study. One trend that we recognize, however, is in the number of tegmen plates, which tends to de- crease throughout the late Paleozoic range of the Pla- tycrinitidae, with the exception of Oenochocrinus, which is an early member with five large orals. Until revision of the Platycrinitidae is made, we recommend that Pleurocrinus be defined as having five prominent orals, with each of the four smaller orals in contact with the larger central anal oral forming the summit of the tegmen with a variable small number of smaller interambulacral and ambulacral plates between them and the radials. Five large orals in the tegmen also are present in Neoplatycrinus Wanner, 1916, Oenochocri- nus Breimer, 1962, and Plemnocrinus Kirk, 1946, in the Platycrinitidae, as well as a number of camerate and cladid genera, all of which lack the intervening smaller plates or have a greatly reduced number of plates between the radials and the large orals. It is highly probable that the laterally directed anal openings evolved repeatedly within the Platycrinites lineage during the late Paleozoic and that species as- signed to Pleurocrinus are homeomorphs. This inter- pretation of Pleurocrinus may be supported by anal- ysis of the stem. Devonian and earliest Carboniferous species of Platycrinites have a continuous twist stem, which gave rise to the segmented twist stem (Webster, 1997) in the Early Mississippian (Kinderhookian). Both types of stems coexisted until Late Mississippian (Chesterian) when the segmented twist stem prevailed. To our knowledge, all Pennsylvanian and Permian spe- cies of Platycrinites have the segmented twist stem and the continuous stem type is unknown even as dis- associated columnals. The stem of Pleurocrinus 1s un- known except for the proximal-most one or two col- umnals, which are round to slightly elliptical, probably becoming elliptical distally as in Platycrinites. If the Pennsylvanian and Permian species of Pleurocrinus were shown to have the segmented twist columnal, it would suggest that the earlier and later species are homeomorphs, there was convergence in the columns, or Pleurocrinus species are a repeated variant of Pla- tycrinites. Pleurocrinus glomerosus, new species Plate 9, figures 1—10 Diagnosis.—Distinguished by having unrounded V- shaped ambulacral grooves, inset radial facets, coarser ornament, and deeply inset sutures. Description.—Calyx globose, small, length 12.9 mm, width 13 mm, widest slightly above tegmen base, ambulacral openings near midlength, all plates very tumid, sutures impressed, subpentalobate in oral view. Cup bowl-shaped, length 8 mm, width 12.8 mm, base flat, walls vertical, unweathered plates show coarse subdued fluted ridge ornament. Basal circlet discoid, 7.6 mm diameter, very gently upflared distally, bearing small (1.5 mm diameter) stem impression centrally. Basals 3, unequal, azygous in A-E interray, horizontal proximally, gently upflared distally. Radials 5, wider (7.2 mm) than long (5.4 mm), slightly convex longi- tudinally, moderately convex transversely, forming walls of cup. Radial facet angustary, inset slightly, subvertical, with deep V-shaped ambulacral groove. Single primibrachial axillary, small, triangular exterior, does not fill facet. First secundibrachials wider than long, extend beyond primibrachial to cover radial fac- et. Arms minimum 2 per ray, at least 10 in total, pro- ject horizontally from cup. Primanal large, length 3.5 mm, width 4 mm, adjoined distally by 2 large plates on each shoulder and shares 2 very small plates with larger plates. Anal opening directed obliquely upward, surrounded by 6 large plates and an inner row of 6 disconnected small plates, or variable number of smaller plates, which may form a double row as a rudimentary anal tube. Tegmen highly inflated with flattened summit, extending slightly beyond cup walls above ambulacral openings, with a central large pos- terior oral at summit surrounded by 6 large and 2 small (in anal interray) plates above large single interam- bulacral plate in each interray; ambulacral opening bordered by 2 small (1 mm or less) quadrangular plates, | to each side of arm mid-point with or without a central small diamond-shaped plate centrally located separating the oral side of the 2 ambulacral tracts join- ing at the base of the first secundibrachial. Stem and distal arms unknown. Remarks.—Pleurocrinus glomerosus n. sp. is more like Tournaisian and Viséan (Wright, 1956) than Perm- ian species (Wanner, 1916, 1937) assigned to the ge- nus, in that the basal circlet is wide and nearly discoid. It differs from those forms by having a shallow basal invagination, and it differs from all described species in that the ambulacral grooves are unrounded V- shaped, the radial facets are inset, the ornament is coarser, and sutures are deeply inset. Measurements were made on the holotype (RGM 361 240). All specimens show some degree of abra- sion destroying most ornamentation. Paratype | (RGM 361 241) shows the primibrachial in two rays and first secundibrachials in one ray. All of the five non-type specimens (lot RGM 290 875) are broken, distorted, or partial calices. Material.—Eight specimens: Holotype (RGM 361 240), two paratypes (RGM 361 241, RGM 361 242), and five other specimens (RGM 290 875) from the Mississippian (Serpukhovian, Pendleian), marly lime- 38 BULLETIN 368 stone above DZ12 of the El Guelmouna Formation at Djenien, east of Palmeraie de, before the pass, Béchar; Winkler Prins collection. Etymology.—Latin meaning like a ball, round, and refers to the globose shape. Pleurocrinus folliculus, new species Plate 10, figures 1—8 Platycrinites tuberculatus Miller, J. S., 1821. Termier and Termier, 1950, p. 86, pl. 212, figs. 10, 11. non Pleurocrinus tuberculatus Wright, 1938, p. 278, pl. 10, figs. 1-4. Diagnosis.—Distinguished by elliptical ambulacral tracts and a greater number of small plates in the teg- men. Description.—Theca globose, small, length 17 mm, width 17.7 mm, base flat, tegmen moderately arched, pentagonal in oral view. Cup medium flat-based bowl- shaped, length 10.4 mm, width 15.6 mm, walls sub- vertical, basal-radial sutures impressed, plates with broad coarse irregular nodose and vermiform orna- ment. Basal circlet fused or tripartite, discoid to very shallow bowl, 9.2 mm diameter, distal edges upflared, barely visible in side view; thickened ridge parallels distal edges; azygous basal in E-A interray. Radials 5, large, 6.4 mm long, 9.5 mm wide, widest at distal end of interradial sutures, straight longitudinally, gently convex transversely, thickest proximally forming ridge overhanging basal circlet. Radial facet angustary, wide, horseshoe-shaped, subvertical, at distal end of radial. Primibrachial small, axillary, triangular in ex- terior outline, moderately convex transversely. First se- cundibrachials much wider than long, laterally extend- ing beyond primibrachial to attach to radial. Second secundibrachial, axillary; elliptical ambulacral tract of outer heterotomous arm much smaller than inner am- bulacral tract. Tertibrachials 2, second axillary. Mini- mum 8 arms per ray, free with second secundibrachial. Tegmen inflated, gently arched; plates large, bearing central tumid node; 5 orals at tegmen summit, anal oral in semicirular contact with 4 others, separated from ambulacral opening by few small ambulacral and in- terambulacral plates. Anal interray has single row of plates above radials. Anal opening on side of tegmen, directed laterally. Stem facet circular, small, 2.4 mm diameter. Distal arms and stem unknown. Remarks.—Pleurocrinus folliculus n. sp. is most closely related to, but differs from, P. glomerosus by having elliptical ambulacral tracts, and a greater num- ber of small plates in the tegmen. Material.—Three specimens: Holotype (RGM 361 243), paratype 1 (RGM 361 244), and paratype 2 (RGM 361 245) from the Oued el Hamar Formation, Pennsylvanian (late Bashkirian), at Foum ech Chegui- ga; Pareyn collection. Etymology.—Latin, meaning an inflated ball, refer- ring to the inflated shape of the tegmen. Genus EUCLADOCRINUS Meek, 1872 Eucladocrinus? asymmetricus, new species Plate 10, figures 9—12 Diagnosis.—Distinguished by four arms per ray and robust size. Description.—Theca globose, large, length 20.4 mm, width 27 mm, base concave, tegmen low flat to very gently arched, elevated above ambulacral open- ings, pentagonal in oral view. Cup medium bowl- shaped, length 12.6 mm, width 25.1 mm, walls sub- vertical, trough along basal-radial sutures. Basal circlet fused, discoid to very shallow bowl, 16.4 mm diam- eter, length 2.5 mm, base concave with shallow con- cavity, distal edges upflared, barely visible in side view. Radials 5, large, 11 mm long, 14.1 mm wide, widest at distal end of interradial sutures, gently con- vex longitudinally and transversely, ornament of low broad nodes. Radial facet angustary, wide, horseshoe- shaped, subvertical; shows 3 facets, single axillary pri- mibrachial overlapped laterally by first secundibrachi- als. Primibrachial small, triangular in exterior outline, with rounded transverse ridge. First secundibrachials much wider than long, laterally attach to radial, with rounded transverse ridge. Second secundibrachial not preserved, axillary. Minimum 4 arms per ray, free with first secundibrachial. Tegmen low, flat to slightly arched; plates large with very coarse bulbous to no- dose centers; ambulacral plates small adjacent to am- bulacral openings, distally become larger; interambu- lacrals with single large plate followed by 2 or 3 small- er plates and larger plates distally. Anal opening sep- arated from radials by single large interambulacral followed by minimum of double row of small plates, projecting vertically. Stem facet circular, large, mod- erately concave, very narrow crenularium, wide areo- la; axial canal small, probably pentalobate. Remarks.—Eucladocrinus? asymmetricus n. sp. is distinguished by its robust size and concave basal cir- clet. Measurements were taken on the holotype (RGM 361 246). The concave base has an asymmetry with a greater declivity at the distal ends, commonly greatest in the D-E interray area. One specimen (RGM 361 253) has the greater declivity in the CD interray. These cups are remarkably similar to that of E. pleurovimen- us (White, 1862) as illustrated by Wachsmuth and Springer (1897, pl. 74, fig. 1). The generic assignment is tentative because Eucladocrinus has two large rami in each ray giving off pinnulate ramuli distally. It is CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 39 assumed that the four ambulacral openings on E.? asymmetricus represent the proximal ends of four rami or arms; it may represent a new genus. All specimens are solution- and abrasion-weathered and have lost most ornament. Paratype | (RGM 361 247) retains a small part of the broad nodes on one radial, shows the development of the proximal end of the two small ambulacral openings on the outer sides of each half ray in two rays, and retains part of the stem facet morphology. The bulbous tegmen plates are best preserved on paratype 2 (RGM 361 248) and paratype 3 (RGM 361 249). Specimen RGM 361 252 retains the stem facet and is abnormal, as the E and A radials are fused into one large armless plate. Speci- men RGM 361 253 has an inflated cup, with more strongly rounded walls, a more bowl-shaped cup, and greatest declivity in the CD interray; features we con- sider to reflect intraspecific variation. Material.—Eight specimens: Holotype (RGM 361 246), four paratypes (RGM 361 247—RGM 361 250), listed specimen (RGM 361 251), and mentioned spec- imen (RGM 361 252) from the Oued el Hamar For- maton, Pennsylvanian (late Bashkirian), southwest of Djebel Horreit. Mentioned specimen (RGM 361 253) from the Oued el Hamar Formation, Pennsylvanian (late Bashkirian), from the north flank of Chebket Mennouna. All Pareyn collection. Etymology.—From the Greek asymmetros, referring to the asymmetry of the basal circlet. Eucladocrinus? sp. Remarks.—Two specimens are tentatively assigned to Eucladocrinus? sp. These specimens are similar to E.? asymmetricus n. sp., but have gently rounded basal circlets. It is uncertain if they represent variation or a separate species. Both specimens are weathered, poor- ly preserved, and unsuitable to serve as types. Material.—Two mentioned specimens (RGM 36] 254) from the Oued el Hamar Formation, Pennsylva- nian (late Bashkirian), southwest of Djebel Horreit; Pareyn collection. Subclass DISPARIDA Moore and Laudon 1943 Remarks.—Recent studies of the higher level clas- sification of the Crinoidea have resulted in major re- allocation of several taxa above the superfamily level (Simms and Sevastopulo, 1993; Ausich, 1997, 1998a). One change with which most echinoderm workers are in agreement is dropping of the Subclass Inadunata because taxa within it are considered polyphyletic. Superfamily BELEMNOCRINACEA S. A. Miller, 1883 Family SYNBATHOCRINIDAE S. A. Miller, 1889 Genus SYNBATHOCRINUS Phillips, 1836 Synbathocrinus sp. Plate 9, figures 11-14 Description.—Cup conical, wider (13.4 mm) than high (8.2 mm), base truncated, walls gently convex becoming concave below radial facets. Basal circlet wider (8.4 mm) than high (2.3 mm), forms lower % of cup. Basals 3, 2 equal, | azygous in anal interray, hor- izontal proximally, steeply upflared distally. Radials 5, wider (7.3 mm) than long (6.4 mm), widest just below radial summit, gently convex transversely, gently con- vex becoming concave distally longitudinally or gently convex longitudinally. Radial facets plenary, upflaring adorally. Transverse ridge narrow, low, extends full width of facet. Outer ligament pit narrow, moderately deep, 0.5 facet width. Narrow transverse ridges and grooves along transverse ridge from ends of ligament pit to distal termination. Outer margin narrow. Muscle areas triangular with gently arched medial areas bor- dered by shallow grooves adoral of transverse ridge and along narrow V-shaped ambulacral groove. No in- ner ligament pit. Anal notch wider (3.1 mm) than deep (0.9 mm), almost entirely on C radial. Stem facet cir- cular, 4.1 mm diameter, impressed in basal circlet. Remarks.—Synbathocrinus is a long-ranging cos- mopolitan crinoid, most common in the Mississippian (Kinderhookian and Osagean) of North America and Tournaisian of Europe (Kesling and Smith, 1963). There are a few records from the late Viséan of Ireland (Waters and Sevastopulo, 1984) and the Serpukhovian (E2) of the Pyrenees (Delvolvé et al., 1996). All Penn- sylvanian species are known from North America (Strimple, 1938; Strimple er al., 1971; Strimple, 1975a; Burdick and Strimple, 1983) and have low bowl-shaped cups with convex radials. Although Syn- bathocrinus sp. May represent a new species, no name is designated because the surface is etched. Ornamen- tation, if developed, is not preserved, and a better specimen is needed to serve as holotype. Material.—Figured cup (RGM 361 255) from the Ain Mezerelt Member, El] Guelmouna Formation at El Aouidja, summit El] Hamar, Mississippian (Serpukhov- ian, El); Legrand-Blain collection. Subclass CLADIDA Moore and Laudon, 1943 Remarks.—The Order Cladida was elevated to sub- class status by Simms and Sevastopulo (1993), a pro- posal that was accepted by Ausich (1997, 1998b), but not by all authors (Webster, 1997; Webster and Houck, 1998; Webster and Hafley in Webster et al., 1999). 40 BULLETIN 368 Ausich (l998b) recognized the cladid orders Cyatho- crinida and Dendrocrinida, but suggested that the re- lationships of the poteriocrines (Suborder Poteriocri- nina of the Treatise, Moore and Teichert, 1978) needed additional study, with which we concur. Order CYATHOCRINIDA Moore and Laudon, 1943 Suborder CYATHOCRININA Bather, 1899 Superfamily CYATHOCRINITACEA Bassler, 1938 Family BARYCRINIDAE Jackel, 1918 Remarks.—Mclntosh (1984) transferred Barycrinus to the Botryocrinidae noting that both had a small pri- manal and larger secundanal. This was accepted by Kammer (2000) and Gahn and Kammer (2002). Al- though we agree that barycrinids may be more closely related to the dendrocrinids than the cyathocrinitids, we do not agree that Barycrinus belongs in the Botry- ocrinidae, because Barycrinus has a pentameric stem and Botryocrinus rammossius Angelin, 1878, the type species, has a holomeric stem. Also, Barycrinus has more advanced radial facets with a transverse ridge and other secondary grooves and ridges radiating from the central pit whereas Botryocrinus has smooth radial facets lacking other morphologic features. The 7Trea- tise (Moore and Teichert, 1978) noted that pentameric stems are developed in some species of Botryocrinus. The significance of the pentameric stem, anal plates, and morphology of the radial facets within the cyath- ocrinitids and dendrocrinids needs detailed analysis, beyond the scope of this study. We would suggest, however, that the results of such an investigation may result in a much greater shuffling of the genera and families within the cyathocrinitids and dendrocrinids. Barycrinidae? indeterminate Plate 10, figures 13-17 Description.—Cup moderately large, ’bowl-shaped, all plates with sharp stellate ridge ornament extending across plate boundaries and medium granular orna- ment. Infrabasals 5, large, distal tips upflared, visible in lateral view. Basals large, length 11.9 mm, width 11 mm, hexagonal (posterior basal heptagonal), gently convex longitudinally and transversely. Radials large, length 12.8, width 15.5, moderately convex longitu- dinally and transversely, incurving distally. Radial fac- et angustary, 8.7 mm = wide, concave, horseshoe- shaped, subvertical to slightly upflared; transverse ridge formed by double row of anastomosing ridges; outer marginal ridge of short adorally directed ridges and grooves; outer ligament furrow wide; muscle areas large, narrowing adorally; ambulacral groove deep V- shaped with extended slit at base of V. Anals 2; large primanal rectangular; larger secundanal pentagonal, on posterior basal, extending above radial summit. Col- umn circular in transverse section, diameter 8.9 mm, heteromorphic; noditaxis N3231323. Columnals with wide crenularium, pentalobate lumen. Remarks.—The description of Barycrinidae? inde- terminate is based on disarticulated plates or parts of cups as follows: one radial, one fragment of a large radial; one cup fragment of one radial, two basals, and the distal tip of an infrabasal plate; one cup fragment of three basals, three radials, and two anal plates; and an associated loose pluricolumnal. Classification of the material is uncertain. The two anals and radial facets are similar to those in the bar- yerinids (sensu Moore and Teichert, 1978). The pri- manal is rectangular, however, it is much larger than typical in the barycrinids or botryocrinids, which have a primanal much smaller than the secundanal. Unfor- tunately, the tegmen and arms of this specimen are unknown leaving additional uncertainty concerning the classification. The ornament and radial facets are sim- ilar to those found in some taxa of the Poteriocriniti- dae. The column is holomeric unlike the pentameric column of Barycrinus. The radial facets have a trans- verse ridge, an intermediate development in the evo- lution of the radial facet morphology of the early clad- ids. Material.—Five specimens: Two partial cups (RGM 361 256, RGM 361 257), one radial (RGM 361 258), one partial radial (RGM 361 259) and one pluricol- umnal (RGM 361 260) from the Akacha-Mazzer For- mation, unit 13 (Pareyn, 1961), Mississippian (late Vi- sean), at Djebel loucha; Pareyn collection. Order DENDROCRINIDA Bather, 1899 Suborder DENDROCRININA Bather, 1899 Superfamily MASTIGOCRINACEA Jaekel, 1918 ?Family MASTIGOCRINIDAE Jaekel, 1918 Genus HEBOHENOCRINUS, new genus Type spectes.—Hebohenocrinus quasipatellus new genus, new species, here designated. Diagnosis.—Cup medium asymmetrical cone- shaped, small; microscopic granular ornament on cup and primibrachials; 5 infrabasals, basals, and radials strongly upflared; radial facets peneplenary; interradial notches narrow; | anal mostly within cup, distally with 4 facets; ?single primibrachial axillary, isotomous branching widely flaring; stem facet horizontal, pen- tagonal, axial canal circular. Description.—As for the type species. Remarks.—Suprageneric classification of this spec- imen is problematic. The cone-shaped cup is a primi- tive feature. The peneplenary radial facets and pentag- CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 41 Text-figure 5—A. Hebohenocrinus quasipatellus n. gen. and sp., g 1 2 I posterior view, holotype RGM 361 262, Hebohenocrinus n. gen. based on holotype; R—radial, P—primanal. onal stem are intermediate evolutionary features in the cladids. Branching on the first primibrachial in at least one ray and presence of a single anal are advanced features (Text-fig. 5). The morphologic features of the steeply inwardly inclined thin radial facets relates them to the cladids. However, the transverse ridge is non- denticulate, whereas most cladids have denticulate transverse ridges. Most high-cone cladids have much thicker radial facets that are shallowly inclined inward, subhorizontal, or inclined outward. The genus is ques- tionably assigned to the Mastigocrinidae based on the primitive cup features but considered an advanced form based on the intermediate and advanced features. Etymology.—From the Greek hebos, meaning at the threshold of manhood, and henos, meaning old or for- mer, in reference to the advanced and primitive char- acters of the specimen, combined with krinon, mean- ing sea lily. eile aca arss quasipatellus, new species Plate 11, figures 5—7; Text-figure 5 Diagnosis.—As for the genus. Description.—Cup medium asymmetrical cone- shaped, longest on posterior side, small, length 6 mm, width at radial summit 7 mm, plates thin, with micro- scopic granular ornament. Infrabasals 5, dart-shaped, length 1.8 mm, width 1.8 mm, strongly upflaring dis- tally, gently convex longitudinally and transversely. Basals 5, hexagonal, except posterior basal heptagonal, length 2.8 mm, width 2.6 mm, slightly concave lon- gitudinally, gently convex transversely. Radials 5, wid- er (3.4 mm) than long (2.4 mm), strongly upflared, gently convex longitudinally and transversely, distal <4.3. B. Plate diagram of edge scalloped. Radial facets peneplenary, thin, slight- ly concave transversely, lens-shaped external of trans- verse ridge, thickest centrally; transverse ridge not denticulate; outer marginal area moderately wide, with moderately deep ligament pit; medium-sized muscle areas slope steeply inward and downward. Interradial notches narrow. Single anal 2.7 mm long, 2.4 mm wide, distal tip slightly above radial summit, distally with 4 small facets. May be | or 2 primibrachials, horseshoe-shaped in transverse section, slightly con- cave longitudinally, strongly convex transversely, bearing microscopic granular ornament as on cup. Is- otomous branching widely flaring. More distal arms, tegmen, and stem unknown. Stem facet horizontal on infrabasal circlet, pentagonal, | mm in diameter; axial canal circular. Remarks.—All plates of Hebohenocrinus quasipa- tellus n. sp. have been replaced by iron oxides. Some of the proximal brachials, including at least one non- axillary and three axillary primibrachials, are dislo- cated, but preserved within the cup. The nonaxillary primibrachial is slightly dislocated from the B radial into the interior of the cup with an axillary primibra- chial dislocated to its left. The B ray apparently had two primibrachials. The other two axillary primibra- chials have no associated nonaxillary primibrachials in association. There are two secundibrachals dislocated into the interior of the cup. There was probably a min- imum of ten arms total. Material.—Holotype (RGM 361 262) probably from between the Hassi Kerma and Djenien forma- tions (Tagnana Formation), Mississippian (late Serpu- khovian, E2), Tiberbatine Anticline, east side of Oued Guir; Pareyn collection. Etymology.—From the Latin quasi, meaning ap- pearing as if, and patella, meaning small dish, and refers to the patelloid process-like appearance of the radial facets in lateral view. Family POTERIOCRINITIDAE Austin and Austin, 1842 As used in the Treatise (Moore and Teichert, 1978), the Suborder Poteriocrinina (of Order Cladida) in- cludes several superfamilies in addition to the Poter- iocrinitacea. The poteriocrinids were separated from the other cladids based on the presence of pinnules. Webster and Hafley (in Webster ef al., 1999) did not accept the development of pinnules as a justifiable character for classification at the level of suborder, pointing out that pinnules have evolved repeatedly in various groups of crinoids during the Paleozoic. They recommended that the Cupressocrinitidae be removed from the poteriocrinids and placed under the Gaster- ocomacea of the Cyathocrinina. Webster and Jell 42 BULLETIN 368 (1999b) recognized the Order Ampelocrinida of the Subclass Articulata as including some genera of the Ampelocrinidae and Cymbiocrinidae, the families Cor- ythocrinidae and Calceolispongiidae, and some un- classified poteriocrinid genera. These changes re- moved a number of genera from the poteriocrinids. In addition, there have been several reallocations of gen- era and families within the Poteriocrinina since pub- lication of the Treatise (Moore and Teichert, 1978). We recommend abandonment of the Suborder Po- teriocrinina, because we believe that the origin of the Poteriocrinitidae is from the Cyathocrinina on the ev- idence of the morphology of the radial facets and structure of the cup, arms, and tegmen. The origin of the superfamilies Rhenocrinacea and Scytalocrinacea is through the Dendrocrinina, on the evidence of the morphology of the radial facet and structure of the tegmen and arms. Other superfamilies within the Po- teriocrinina (Treatise usage) also are believed to be derived from either the Cyathocrinina or Dendrocri- nina and require study beyond the scope of this paper for proper reallocation. Taxa described and discussed herein are assigned to poteriocrinine families as used in the 7reatise, but are not considered poteriocrinids unless assigned to the Family Poteriocrinitidae. Genus BALEAROCRINUS Bourrouilh and Termier, 1973 Remarks.—The primibrachials of Balearocrinus are quite distinctive. They are exceedingly short and the syzygial articulation leaves them firmly interlocked on the radial. Proximal primibrachials may be partially fixed to the radials. In the illustrations of Bourrouilh and Termier (1973, pl. 27, fig. 4; fig. 3, no. D) it is apparent that the first primibrachial is overlapped lat- erally by the second and perhaps higher primibrachials on the E-ray radial (right side of figure). On the A-ray radial (center radial, pl. 11, fig. 15) the first primibra- chial is tapering on the lateral ends and is overlapped by the second primibrachial near or at the radial mar- gin. The primibrachials on the B radial (left side of figure) also taper toward the lateral end but extend to the end of the facet. Additional evidence of the over- lapping of the first primibrachial by the second pri- mibrachial is present on the illustrations of the bra- chials by Bourrouilh and Termier (1973, pl. 28, figs. 1-3). The crenularium of the brachial of their figure 3 terminates along the sides without reaching horizontal radiations (i.e., less than a hemisphere). We interpret this as a first primibrachial facet, whereas the facets shown on their figures 1 and 2 radiate in a complete hemisphere, which we interpret as facets on distal bra- chials. We consider the narrow first primibrachial be- ing overlapped by the second primibrachial to be an important morphologic character of the genus but are uncertain how variable this feature is within the genus. These radial facets are related to the angustary radial facets of Poteriocrinites and the peneplenary radial facets of Rhabdocrinus, neither of which have the first primibrachial overlapped laterally by the second pri- mibrachial. The short brachials of Rhabdocrinus with radiating crenularia are very similar to those of Bal- earocrinus, but the latter lacks the interprimibrachials of the former. Balearocrinus pareyni, new species Plate 11, figures 13-15 Cf. Rhabdocrinus scotocarbonarius (Wright, 1937). Pareyn, 1961, p 223: Diagnosis.—Cup high conical, truncated base, plates smooth, very shallow apical pits, 3 anals in primitive position; plenary radial facets concave, slope outward; primibrachials very short, first primibrachial overlapped laterally by second primibrachial; crenu- larium on outer margin of brachials and anals; proxi- mal columnals round, heteromorphic, NI noditaxis, syzygial articulation. Description.—Cup high conical, 18.5 mm _ long, 14.9 mm wide (minimum), 18.5 mm wide (maximum), 16.7 mm (average), truncated base, shallow apical pits, plates smooth. Infrabasals 5; proximal half covered by proximal columnal, probably horizontal; visible distal half strongly upflared, length 5.5 mm, width 7.3 mm. Basals 5, slightly longer (9 mm) than wide (7.8 mm), hexagonal (except posterior heptagonal), straight to faintly concave longitudinally, gently convex trans- versely. Radials 5, equidimensional (7.9 mm), strongly upflared, straight longitudinally, gently convex trans- versely. Radial facets plenary, concave, strongly rounded outer rim, slope outward. Anals 3, primitive position. Primanal largest, 6.6 mm long, 6.1 mm wide, pentagonal, supporting third anal distally. Secundanal pentagonal, 6.4 mm long, 6.1 mm wide, distal tip at radial summit. Tertanal equidimensional, 4.7 mm, dis- tal tip above radial summit. Tube plate above tertanal with externally radiating crenularium of fine culmina and crenellae. Primibrachials very short, uniserial, strongly rounded externally, 3 commonly retained in cup, bear externally radiating crenularium as on tube plate, syzygial articulation; first primibrachial over- lapped laterally by second primibrachial. Second pri- mibrachial tapers on lateral edges, reaching end of ra- dial facet. Distal arms and tegmen unknown. Proximal columnals transversely elliptical, long axis 8.6 mm, short axis 7.8 mm, 8.2 mm average, heteromorphic, noditaxis N1, syzygial articulation. Remarks.—Balearocrinus pareyni n. sp. has a taller CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 43 cup and narrower first primibrachials than B. breimeri reported from Viséan strata of Minorca (Bourrouilh and Termier, 1973) and B. cantabricus from the late Viséan of the Cantabrian Mountains, northern Spain (Herbig, 1982, 1994). This is the first report of the genus from northern Africa. The specimen is crushed slightly, normal to the A ray-posterior plane of symmetry. Attached proximal columnals are considered originally to have been round transversely and distorted to the elliptical shape by compaction. Material.—Holotype (RGM 361 261) from the Mazzer Formation, Mississippian (late Viséan), Mader el Mahjib syncline, bed 13; Pareyn collection. Etymology.—Named for C. Pareyn who found the specimen. Superfamily SCYTALOCRINACEA Moore and Laudon, 1943 Family SCYTALOCRINIDAE Moore and Laudon, 1943 Genus SCYTALOCRINUS Wachsmuth and Springer, 1880 Scytalocrinus sp. Plate 11, figure 16 Phanerocrinus noy. sp. Pareyn, 1961, p. 76 [sic]. Description.—Cup truncated medium cone, length 8.7 mm, width 16.6 mm (average), medium granular oranment on all plates including secundibrachials. In- frabasal circlet with basal concavity, diameter 7.6 mm, proximally horizontal, distal tips weakly upflared, barely visible in lateral view; infrabasals 5. Basals 5, slightly wider (7.1 mm) than long (6.1 mm), hexagonal (CD basal may be heptagonal if in contact with se- cundianal), gently convex longitudinally and_ trans- versely, form lower half of cup wall. Radials 5, much wider (10.6 mm) than long (6.6 mm), pentagonal, gently outflaring, slightly convex longitudinally, mod- erately convex transversely. Radial facet plenary. An- als 3, primitive to slightly advanced arrangement. Ra- dianal largest, pentagonal or hexagonal, either under- lies both secundanal and tertanal or abuts secundanal and underlying tertanal. Secundanal mostly in cup, in line of radials. Tertanal proximal half in cup. Axillary single primibrachial widest at base, constricted medi- ally, strongly convex transversely, concave longitudi- nally. First secundibrachials widest at base, narrowing distally, slightly cuneate, concave longitudinally, mod- erately convex transversely. Stem facet round, 2.6 mm diameter, wide crenularium, no areola, circular axial canal. Remarks.—Both specimens of Scytalocrinus sp. are distorted through compaction with the one specimen with proximal brachials of three rays preserved partly enclosed in matrix and positioned above the oral sur- face of the more completely exposed cup of the other specimen. The shape of the distal brachials and the distal branching patterns are unknown. These specimens closely resemble S. robustus (Hall, 1861) in cup shape and structure, but differ by the presence of granular ornament. Ornamentation is not common in species assigned to Scytalocrinus (most species are described as having smooth plates or lack- ing ornamentation). Scytalocrinus disparilis (Miller and Gurley, 1890) was described as having smooth or granular plates and S. cantonensis (Miller and Gurley, 1890) was illustrated (pl. 8, figs. 3, 4) as having gran- ular ornamentation, but the ornamentation was not mentioned in the description. Scytalocrinus seafielden- sis (Wright, 1948) was described as having smooth or very finely frosted plates. Webster (1997) recognized three clades within Scytalocrinus based principally on the shape of the brachials. Because the distal brachials of these specimens are unknown they are left in open nomenclature, but are thought to represent a new spe- cies. Material.—Two specimens (RGM 361 263) from the base of Mouizeb el Atchane Member, Ain el Mizab Formation, Mississippian (Serpukhovian, E2), at Gadet Sedra; Pareyn collection. Genus HYDRIOCRINUS Trautschold, 1867 Hydriocrinus? confusus, new species Plate 11, figures 1—4 Diagnosis.—Distinguished by more elongate pri- mibrachials, an advanced primitive anal condition with the secundanal not in contact with the posterior basal, and a round stem. Description.—Cup elongate vase-shaped, length 8.4 mm, width 5.8 mm, widest slightly below distal end of basals, surface ornament of microscopic granules. Infrabasals 5, dart-shaped widening distally, visible length 3 mm, width 2.1 mm, straight longitudinally, gently convex transversely. Basals 5, large, length 3.7 mm, width 2.1 mm, hexagonal, moderately convex longitudinally and transversely, inflaring gently distal- ly. Radials 5, large, length 3.1 mm, width 3.6 mm, pentagonal, gently outflaring proximally, inflaring dis- tally, gently convex transversely. Radial facets plena- ry, slope inward moderately, bear transverse ridge, sharp outer marginal ridge, moderately deep outer lig- ament pit, and deep wide muscle areas. Anals 3. Pri- manal hexagonal, in contact with C radial, BC (nar- rowly) and CD basals, D radial, secundanal, and ter- tanal. Secundanal pentagonal, distal tip slightly above 44 BULLETIN 368 radial summit adjoined by 2 tube plates, tertanal, pri- manal, and D radial. Tertanal hexagonal, distal half above radial summit, adjoined distally by 2 tube plates, one in common with secundanal. E ray primibrachial elongate, nonaxillary, strongly rounded transversely, slight hour-glass shape. Axillary C and D ray primi- brachials much shorter (2 mm) than E ray primibra- chial (3.2 mm). Secundibrachial on anal side of D ray primibrachial slightly cuneate. More distal brachials and tegmen unknown. Proximal columnals transverse- ly round, tapering from 2.1 mm diameter at infrabasal facet to 2 mm on distal end of second columnal. Col- umnal facet with crenularium and areola of equal width; lumen shape unknown. Remarks.—The single specimen of Hydriocrinus? confusus nN. sp. is replaced with iron oxides and un- crushed. The anals are in a slightly advanced primitive condition with the secundanal not in contact with the posterior basal. The small size and vase shape of the cup are similar to Hydriocrinus pusillus Trautschold, 1867, reported from the Moscovian of Russia. Hydriocrinus, however, has a pentagonal stem, relatively short medially con- stricted primibrachials, rectilinear brachials, and arms that branch at least twice in some rays. It is uncertain from the original description and illustrations of Hy- driocrinus if all the primibrachials are the same length and if all are axillary. The two primibrachials of H.? confusus are constricted medially, but relatively much longer than those of H. pusillus Trautschold. The only single secundibrachial preserved on H.? confusus is slightly cuneate. Also, the round stem of H.? confusus is in contrast to the pentagonal stem of H. pusillus. Hydriocrinus? confusus with the slightly advanced po- sition of the anals occurs stratigraphically earlier (Ser- pukhovian) than H. pusillus, a Moscovian form, in which the anals are in the primitive position with the secundanal in contact with the posterior basal. Comparison of Hydriocrinus? confusus with other Carboniferous species assigned to the genus led us to question the generic assignment of each. In discussions with other crinoid workers, it was suggested that all Devonian and Early Carboniferous species assigned to Hydriocrinus actually belong to other genera (N. G. Lane, personal communication). The partially exposed cup of H. mjassoedowae Yakovlev (1926) has a more bowl shape, impressed sutures, and a round stem facet. It is not considered a Hydriocrinus. Two species, H. lorraineae Strimple and Watkins (1969) and H. tur- binatus Strimple (1971), have conical-shaped cups, 10 arms, isotomous branching on the axillary primibra- chial, cuneate brachials, and pentagonal stems with round lumens. These two species are considered to be- long to the same genus but not to Hydriocrinus. The second set of arms (Strimple and Watkins, 1969, pl. 34, figs. 6, 7) assigned to H. lorraineae have much more cuneate brachials and are not from the same spe- cies. The dorsal cup of H. acehillensis Pabian and Strimple (1985) is a conical cup, possibly belonging to the same genus as H. lorraineae and H. turbinatus. Their description states that the specimen has three anals, as shown in the posterior view of the cup (Pa- bian and Strimple, 1985, fig. 251), however the oral view (fig. 25k) shows a specimen with six radial facets and no anals. It appears that two different specimens are illustrated, but the description and remarks are based on a single specimen. Another dorsal cup, H.? roset Moore and Plummer, 1938, referred to Phacel- ocrinus by Strimple (1971), was considered to be the progenitor of Hydriocrinus in North America by Strimple and Watkins (1969) and Pabian and Strimple (1985). This specimen has an asymmetrical conical cup, considerably larger than Hydriocrinus cups, and probably belongs to a scytalocrinid, perhaps Hypse- locrinus or Phacelocrinus. The anal structure of Melbacrinus has been consid- ered to be comparable to that of Hydriocrinus (Strim- ple, 1971). The lower conical cup, elongate primibra- chials, and round stem of Melbacrinus, however, are quite distinct. The elongate primibrachials and round stem are comparable to those of H.? confusus, but the cup shapes differentiate these two genera. Material.—Holotype (RGM 361 264) from a hori- zon between the Hid el Kef and Djenien members, Djenien Formation, Mississippian (Serpukhovian, E2), north of Djebel Arlal; Pareyn collection. Etymology.—From the Latin confusio meaning mix- ture, disorder. Family AMPULLACRINIDAE, new family Type genus.—Ampullacrinus n. gen. Diagnosis.—Crown slender elongate, cup medium bowl or globe shape, shallow basal concavity, radial facets plenary, 3 anals in primitive position with se- cundanal in contact with posterior basal, arms 10, branching isotomously on single primibrachial, 3 en- toneural canals in brachials, advanced articular facets with transverse ridges on all proximal brachials, bra- chials slightly cuneate, proximal columnals round to weakly pentagonal, axial canal pentalobate. Remarks.—Sevastopulo and Keegan (1980) report- ed the discovery of triple aboral nerve canals, in an isolated brachial from the Mississippian (late Viséan) Charlestown Main Limestone of Scotland, when de- scribing a technique to study stereom structure of fos- sil crinoids. Ampullacrinus is the first report of the triple canals in an articulated partial crown. If it did not have the three entoneural canals in the brachials, CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 4 Ampullacrinus would be considered a scytalocrinid. Entoneural canals and advanced articular facets on the brachials are two features of Ampullacrinus shared with the articulates. Entoneural canals evolved several times in crinoids. They are present in crotalocrinids, euspirocrinids, some codiacrinids, gasterocomacids, encrinids, and the articulates as illustrated in the Treatise (Moore and Teichert, 1978, among others). Except for the articu- lates and encrinids, all of these groups became extinct in the Paleozoic. The encrinids became extinct in the Triassic. Crotalocrinids, euspirocrinids, codiacrinids, and gasterocomacids lack advanced articular facets on the brachials, except at arm divisions, and have a sin- gle entoneural canal (Moore and Teichert, 1978). The articulates have two entoneural canals and advanced articular facets on the brachials (Webster and Jell, 1999b). The encrinid Chelocrinus has two entoneural canals and have advanced articular facets on the un- iserial brachials, and two entoneural canals on the dis- tal biserial brachials (Hagdorn, 1982). Webster and Jell (1999b) considered the synapo- morphic feature that defines the Articulata to be the development of syzygial brachial pairs in the arms. Ampullacrinus lacks the distal parts of the arms be- yond the ninth secundibrachial. There is no indication of development of syzygial brachial pairs within the nine secundibrachials. Syzygial brachial pairs are not developed in Corythocrinus or Archaeoisocrinus until the fourth secundibrachial, and Chlidonocrinus is de- fined in Moore and Teichert (1978, p. T674) as having **Arms branching more than twice, some with syzygial paired brachials.”” This latter statement implies either that not all arms have syzygial paired brachials or that some species of Chlidonocrinus do not have syzygial paired brachials. Those species lacking syzygial paired brachials may be improperly assigned to Chlidonocri- nus. Development of the articular facets on brachials oth- er than axillary brachials and their distal counterparts is considered an important morphologic character of the ampelocrinids, demonstrating that they are primi- tive articulates. In some instances preservation of ar- ticulated arms or recrystalliation could easily mask the small entoneural canals, but the articular facets may be less affected. Thus, the development of, or combi- nation of, any one or more of the three synapomorphic features, two entoneural canals, syzygial brachial pairs, or articular facets on brachials other than axillary bra- chials, should be used for recognition of Paleozoic ar- ticulates. Logocrinus Goldring (1923) was considered the progenitor of the articulate crinoids based on the pres- ence of syzygial paired brachials by Webster and Haf- Nn ley (in Webster et al., 1999). This includes L. geni- culatus Goldring, 1923, L. infundibuliformis Goldring, 1923, L. kopfi (Goldring, 1946) L. brandoni Sigler et al., 1971, and ?L. conicus Kesling, 1968. The arms of L. conicus are unknown above the primibrachials, thus it is questionably assigned to the genus. The arm frag- ment with syzygially paired brachials, identified as Charientocrinus ithacensis by Goldring (1923, pl. 53, fig. 3), belongs to L. geniculatus or L. infundibulifor- mis. Logocrinus lacks entoneural canals (George Mc- Intosh, personal communication, December 2000). Lo- gocrinus probably evolved from an early glossocrinid and is herein questionably referred to the Family Cor- ythocrinidae but may be the progenitor of the primitive articulates. Including Logocrinus, the Corythocrinidae ranges from Givetian to the Sakmarian-Artinskian boundary. Ampullacrinus is specifically excluded from the primitive articulates because it lacks syzygial paired brachials and has three entoneural canals. Ampullacri- nus is probably derived from a scytalocrinid with de- velopment of the three entoneural canals. This is an- other instance of polymorphic evolution of entoneural canals not in the lineage of the articulates. Hagdorn (1995) reported that encrinids were derived (Encrini- dae, Traumatocrinidae, and Ainigmacrinidae) from a proto-articulate crinoid. Because encrinids lack syzyg- ial paired brachials they are excluded from the artic- ulate lineage. Encrinids are a separate example of evo- lutionary development of entoneural canals from an unspecified late Paleozoic cladid, perhaps like Aesi- ocrinus or one of the scytalocrinids with two primi- brachials. Their evolution included loss of the anals, development of biserial brachials distally, articulation facets with transverse ridges on proximal brachials minimally, and entoneural canals. AMPULLACRINUS, new genus Text-figure 6 E Type species.—Ampullacrinus marieae n. gen., new species, here designated. Diagnosis.—As for the family. Description.—As tor Ampullacrinus marieae, new species. Remarks.—Without the presence of the muscular and ligamentary facets and the entoneural canals, vis- ible only on the brachial facets, this taxon would be assigned to Scytalocrinus on the basis of the cup and arm morphology. Etymology.—From the Latin, ampulla, meaning flask and refers to an irregular flask-like shape of the enclosed crown. 46 BULLETIN 368 Ampullacrinus marieae, new species Plate 12, figures 1-10; Text-figure 6 B—E Cf. Fifeocrinus tielensis (Wright, 1936). Pareyn, 1961, p. 76. Diagnosis.—Distinguished by having a medium bowl-shaped cup, very fine granular ornament grading into vermiform and aligned granules, and a weakly pentagonal stem. Description.—Cup medium bow] shape, wider than long, widest at radial summit, sutures flush, not im- pressed, very fine granular grading into vermiform and aligned ornamentation. Infrabasal circlet subhorizon- tal, 6.1 mm diameter. Infrabasals 5, dart-shaped, slight- ly longer than wide, distal tips visible in lateral view, proximal ends downflaring in shallow basal concavity. Basals 5, wider than long, gently convex transversely and longitudinally. Radials 5, largest plates in cup, wider than long, gently convex transversely and lon- gitudinally. Radial facets plenary; transverse ridge nar- row, sharp crested; outer ligament pit 4% length trans- verse ridge, deep, slopes under ridge; outer marginal ridge with transverse ridges and grooves across facet; outer margin shelf moderately wide centrally, crescent- shape; muscle areas not exposed. Anals 3, large, in primitive position. Primanal largest, oblique position, adjoined by C radial, BC and CD basals, secundanal and tertanal. Secundanal elongate, distal half above ra- dial summit. Primibrachials wider than long, strongly convex transversely, gently convex longitudinally, ax- illary; primibrachials unequal in length, A longest, C and D second longest, B and E shortest. First secun- dibrachials wider than long, strongly convex trans- versely, straight longitudinally. Arms 2 per ray, 10 to- tal if no branching above primibrachials. Brachials strongly rounded transversely, straight longitudinally, slightly cuneate. Brachial facets symmetrical to slight- ly asymmetrical, bear nondenticulate transverse ridge, medium depth ligament pit, denticulate outer marginal ridge, and narrow outer ligament furrow; muscle areas large, transversely irregularly ridged, separated from transverse ridge by wide, coarsely crenulate articular fields along lateral sides and admedial smooth intera- reas; intermuscular furrow shallow, lacking recogniz- able central pit. Three small entoneural canals (Text- fig. 6); central canal medial between transverse ridge and intermuscular furrow; 2 elliptical lateral canals di- verging adorally to central canal along aboral end of intermuscular furrow. Stem facet weakly pentagonal; axial canal pentagonal; crenularium with 4 to 6 coarse crenula (longest centrally) per infrabasal. Proximal 2 columnals weakly pentagonal, heteromorphic; latus rounded; minimum N1 noditaxis. Measurements given in Table 9. Remarks.—The holotype of Ampullacrinus marieae Text-figure 6.—A-—C. Camera-lucida drawings of brachial facet of Ampullacrinus showing three entoneural canals. A. Ampullacrinus tritubulus n. gen., n. sp. Distal facet of second secundibrachial, right side of A ray. Paratype 2, RGM 361 335, 23. B. Ampullacrinus mariea n. gen., n. sp. Distal facets of first secundibrachials, E ray. Paratype 2, RGM 361 329, *7.5. C. Ampullacrinus mariea n. gen., n. sp. Distal facet of third or fourth secundibrachial, left side of A ray. Paratype 2, RGM 361 329, «12. D. Ampullacrinus marieae n. gen. and sp., posterior view, holotype RGM 361 330, «2.2. E. Plate diagram of Ampullacrinus n. gen. based on holotype and paratypes of A. marieae n. sp.: R radial, P—primanal, S—secundanal, T— tertanal. n. sp. is crushed with elongation in the A ray-posterior axis, has some chipping of cup plates, has up to 10 secundibrachials preserved, and shows the entoneural canals and brachial facets. The cup of paratype 1| is not crushed, lacks the D radial, has crushed arms, and retains the first and part of the second columnals; it also retains up to the third secundibrachial. Paratype 2 (RGM 361 329) is crushed with elongation normal to the A ray-posterior axis, has up to the third secundi- brachial preserved, and retains the best preservation of CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 47 Table 9—Measurements in mm for Ampullacrinus mariea n. gen., nN. sp. Type Paratype 2 Holotype Paratype | Spec. no. (RGM) 361 329 361 330 361 331 Specimen length 19.1 23.2 17.6 Cup length 8.5 Tes) VS Cup width maximum 17.8 16.5 18.6 Cup width minimum 12.0 14.1 18.0 Cup width average 14.9 15.3 18.3 IBB length De) 3 3.5 IBB width 2.6 3 355 BB length 5:2 4.9 6.2 BB width 5.8 5.4 (ong RR length 5.3) 5.5 6.4 RR width 8.1 8.4 10.4 Primanal length 5.6 5:9) 6.8 Primanal width 4 4.5 4.7 Secundanal length 5 4.2 4.8 Secundanal width Sh9/ 4.3 4.5 Primibrachial length 52. 4.2 5 Primibrachial width 8.4 7.4 8.4 Ist secundibrachial length 332 2.8 3.2 Ist secundibrachial width 4.5 3.5 She) Diameter stem facet 2.7 avg. Dell Diameter proximal columnal 3.1 the entoneural canals and articular facets of the bra- chials. Paratype 3 is crushed with elongation in the E- A interray-C ray axis, has crushed arms retaining up to the second secundibrachial, and has four solution- etched proximal columnals. Material.—Four specimens from the Mouizeb el At- chane Member, Ain el Mizab Formation, Mississippian (Serpukhovian, E2). Paratype 2 (RGM 361 329) from Djebel Béchar; Legrand-Blain collection. Holotype and paratype | (RGM 361 330; RGM 361 331) from the ravine at Mouizeb el Atchane and paratype (RGM 361 332) from Ravine de Djenien; Pareyn collection. Etymology.—Named for Marie Legrand-Blain who found one of the specimens. Ampullacrinus tritubulus, new species Plate 11, figures 17—23; Text-figure 6 A Diagnosis.—Distinguished by having a medium globe-shaped cup, fine granular and anastomosing or- nament, and a round stem. Description.—Cup medium globe shape, length 5.8 mm, width 14.8 mm (average), shallow basal concav- ity, plates slightly inflated, sutures lightly impressed, fine granular and anastomosing ornament. Infrabasal circlet pentagonal, shallowly invaginated, 5.3 mm di- ameter. Infrabasals not visible in lateral view. Basals 5, AB, DE, and EA hexagonal, BC and CD heptagonal for adjoining anals, length 5.3 mm, width 5.2 mm, moderately convex longitudinally and_ transversely, outflaring forming lower half of cup wall. Radials 5, pentagonal, wider (8.1 mm) than long (4.4 mm), mod- erately convex longitudinally and transversely, slightly outflaring distally. Radial facet plenary, sloping out- ward slightly. Anals 3, in primitive position. Primanal largest, length 4.5 mm, width 4 mm, pentagonal, abut- ting secundanal, supporting tertanal. Secundanal hex- agonal, directly above posterior basal, slightly less than half extending above radial summit. Tertanal smallest, hexagonal, slightly more than half extending above radial summit. Single primibrachials axillary, wider (7.6 mm) than long (4.2 mm estimate). Brachials strongly rounded transversely, straight longitudinally, slightly cuneate. Brachial facets symmetrical to slight- ly asymmetrical, bear nondenticulate transverse ridge, medium depth ligament pit, denticulate outer marginal ridge, and narrow outer ligament furrow; muscle areas large, transversely irregularly ridged, separated from transverse ridge by wide, coarsely crenulate articular fields along lateral sides and admedial smooth interar- eas; intermuscular furrow shallow, lacking recogniz- able central pit. Three small entoneural canals; central circular canal medial between transverse ridge and in- termuscular furrow; two elliptical lateral canals di- verging adorally to central canal along aboral end of intermuscular furrow. Branching isotomous, 2 arms per ray, 10 arms total if no distal branching. Secun- 48 Table 10.—Measurements in mm for Cosmetocrinus? sp. BULLETIN 368 Spec. no. (RGM) 290 874 361 265 Cup length 5) 7.3 (crushed) Cup width 6.5 9.6 max., 5.3 min., 7.4 avg. Infrabasal length 1.9 (est.) 2.1 Infrabasal width 129 2 Basal length 2.6 3:2 Basal width 235 Qf Radial length 2. 3 Radial width See Sul; Primibrachial length Sh 3.5 Primibrachial width 2.8 3.8 Diameter proximal columnal or impression 15 2.6 dibrachials much wider than long, moderately cuneate. Proximal stem round, heteromorphic; minimum NI] noditaxis; lumen pentalobate. Remarks.—The cup of the holotype (RGM 361 333) of Ampullacrinus tritubulus n. sp. is slightly crushed normal to the A ray-posterior plane of symmetry. Dis- tal parts of the arms are not preserved except for a fragment of one arm retained among the arm bases. The infrabasal circlet is not preserved. Paratype | (RGM 361 334) retains the basal circlet (which is crushed inward slightly), the D and E radials are bro- ken with parts missing, the arms are not preserved, and the abraded proximal stem 1s attached. Paratype 2 (RGM 361 335) lacks the infrabasal and basal circlets and retains proximal parts of all arms up to the third secundibrachial. Without the arms showing the entoneural canals, Ampullacrinus tritubulus has some resemblance to Mooreocrinus. The cup has a closely similar shape and may bear similar ornamentation. It differs, however, by having much thinner plates, less impressed sutures, and lacking the stitched appearance along the sutures typical of most cromyocrinids. Ampullacrinus tritu- bulus differs from A. marieae by having coarser or- nament, a medium globe-shaped cup, and a round stem. Material.—Three specimens: Holotype (RGM 361 333) from the base of the Ain el Mizab Member, Ain el Mizab Formation, Mississippian (Serpukhovian, El), from Foum es Sba. Paratype | (RGM 361 334) from the top of the Djenien Member, Djenien For- mation, Mississippian (Serpukhovian, E2), at Chebket Djihani. Paratype 2 (RGM 361 335) from the Djenien Member, Djenien Formation, Mississippian (Serpu- khovian, E2), at Chebket Djihani. All Pareyn collec- tion. Etymology.—From the Latin tri, meaning three, and tubus, meaning pipe or tube, and referring to the three entoneural canals. Family APHELECRINIDAE Strimple, 1967 Genus COSMETOCRINUS Kirk, 1941 Cosmetocrinus? sp. Plate 11, figures 8—12 Description.—Cup small, high cone-shaped, unor- namented. Infrabasals 5, equidimensional to slightly longer than wide, proximal end horizontal for stem facet, distal three-fourths upflared, visible in lateral view, forming basal one-fourth of cup, moderately convex transversely. Basals 5, slightly longer than wide, straight longitudinally, moderately convex trans- versely, AB, DE, and EA hexagonal, BC and CD sep- tagonal in contact with anals. Radials 5, shorter than long, straight longitudinally, moderately convex trans- versely, outflaring, maximum width at base of very narrow interradial notch. Radial facets peneplenary, slightly outset, subhorizontal. Radial-primibrachial su- ture gaping. Anals 3, normal position. Primanal and secundanal approximately same size. Primanal pentag- onal elongate. Secundanal hexagonal, extending slight- ly above radial summit. Anal series continues as two parallel columns of stacked polygonal plates in base of slender anal tube. Single primibrachials axillary in all rays, isotomous branching. Brachials strongly rounded transversely, straight to slightly concave lon- gitudinally, hourglass-shaped. Proximal secundibrachi- als shorter than primibrachials, shape similar to pri- mibrachials, cuneate. Arms 10 in preserved portion. Proximal columnal round transversely, lumen subpen- talobate. Measurements given in Table 10. Remarks.—These two partial crowns are tentatively assigned to Cosmetocrinus because they have very narrow interradial notches, that are essentially con- cealed by the outset radial facets. Interradial notches are not known in any species of Cosmetocrinus. The primibrachials are of differing lengths, with the B ray longest on both specimens. Differing lengths of the primibrachials is a feature common to Cosmetocrinus CARBONIFEROUS (VISEAN—-MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 49 Table 11.—Measurements in mm for Dicromyocrinus vastus n. sp. Type Holotype Paratype | Paratype 2 Paratype 3 Paratype 4 Spec. no. (RGM) 361 266 361 267 361 268 361 269 361 270 Crown length (incomplete) 17.4 10.8 Cup length 8.8 Sei 13.5 10.9 7.9 Cup width 15 10.8 6.5 5.4 14.6 Diameter infrabasal circlet 6.2 4.3 6.9 4.8 6.8 Basal length 5.4 Shi) 4.8 3:2 5.6 Basal width Dal, 4 533) 4.5 6.3 Radial length Sy) 32D 5:2 B53 6 Radial width 8.3 5.3, eS) 5.8 8 Primanal length 5.3 3.4 4.2 Bh) 4.1 Primanal width 3.6 2.6 4 32 3.4 Primibrachial length 3.8 6 Primibrachial width 7.6 4.1 Stem facet diameter 2.8 1.4 Proximal columnal diam. DES 1.8 7.4 and several other genera of the cladids. The small con- ical cup is also known among a few genera of the Scytalocrinidae, but none has interradial notches and the brachials are quite long, branching on primibra- chial two or higher. Material.—Two specimens (RGM 290 874, RGM 361 265) from marly limestone above DZ12 of the El Guelmouna Member, El Guelmouna Formation, Mis- sissippian (Serpukhovian, E1), at Djenien, east of Pal- meraie de, before the pass, Béchar; Winkler Prins col- lection. Superfamily CROMYOCRINACEA Bather, 1890 Family CROMYOCRINIDAE Bather, 1890 Genus DICROMYOCRINUS Jaekel, 1918 Dicromyocrinus vastus, new species Plate 12, figures 11—21; Plate 17, figures 25, 26 Diagnosis.—Distinguished by the medium-sized or- namentation, lesser degree of suture impression, ter- tanal in contact with primanal, and a slightly upflaring infrabasal circlet. Description.—Crown small, cylindrical with arm girdle in proximal part of secundibrachials. Cup me- dium bowI- to globe-shaped, incurving at distal tips of radials, base subhorizontal to shallow basal invagina- tion; all cup plates and proximal brachials bear me- dium granular to vermiform ornament; apical pits shal- low, sutures weakly to moderately impressed. Infra- basal circlet horizontal proximally, downcurving to horizontal medially, gently upcurved distally. Infra- basals 5, dart-shaped, widest at basal plane, distal tips barely visible in lateral view. Basals 5, large, slightly wider than long, AB, DE, and EA hexagonal, BC and CD heptagonal to accomodate adjoining anals, mod- erately convex longitudinally and transversely, outflar- ing proximally, subvertical distally, form lower half of cup wall. Radials 5, much wider than long, widest slightly below radial summit, moderately convex lon- gitudinally and transversely, incurving distally, form upper half of cup wall. C radial with shortened side adjacent to anal series; C and D radials not as wide as A, B, and E radials. Radial facet plenary, sloping out- ward slightly, with wide outer ligament area, moder- ately deep ligament pit, straight transverse ridge nearly plenary, wide muscle areas. Anals 3, primitive to in- termediate advanced position; primanal iargest, pen- tagonal, oblique, in contact with C radial, BC and DC basals or CD basal only, secundanal, and tertanal; se- cundanal hexagonal, directly above CD basal, one- third above radial summit; tertanal smallest, hexago- nal, slightly less than half above radial summit. Single primibrachial axillary in all rays, much wider than long, moderately convex transversely, longitudinally convex proximally becoming concave distally, mod- erate gape with radial. Branching isotomous, 2 arms per ray, 10 arms total unless additional branching dis- tally. Proximal columnals circular transversely, hetero- morphic. Noditaxis at least N212. Lumen pentalobate. Crenularium narrow, on outer half of facet. Measure- ments given in Table 11. Remarks.—Weathering apparently has destroyed much of the ornament on the cup plates of most spec- imens of Dicromyocrinus vastus n. sp. leaving an abraded surface with remnants of median coarse no- dose and anastomosing ridge ornament. The ornamen- tation is intermediate in size between the fine and coarse clades recognized by Webster (1981). It is most 50 BULLETIN 368 similar to that of D. medius Moore and Strimple (1973). These two species differ in the lesser degree of suture impression, the tertanal is in contact with the primanal, and the infrabasal circlet is slightly upflared in D. vastus, whereas the sutures are deeply impressed, the tertanal is not in contact with the primanal, and the infrabasal circlet is horizontal to slightly impressed in D. medius. It is distinguished from other species of the genus by the medium-sized ornamentation, not being as coarse as in D. granularis Easton (1962) from Low- er Pennsylvanian strata from North America. The or- nament is coarser and the base flatter in D. vastus than in D.? papillatus Worthen (1882) from Upper Missis- sippian strata of the Illinois Basin, North America. The medium bowl-shaped cup of D. vastus is an interme- diate form between the more primitive high-bowl or medium-globe shape of D. catillus n. sp. and the ad- vanced low-bowl shape of D. ?invaginatus n. sp., al- though it occurs stratigraphically below both species. The arm girdle or constriction of the arms above the radials in the enclosed position (Webster and Lane, 1967) is a common morphologic feature of most cro- myocrinids and some other late Paleozoic cladids and articulates (Webster and Jell, 1999b). Dicromyocrinus vastus belongs to the more primi- tive group of the genus with a rounded base but shows a slightly advanced condition with a shallow basal in- vagination involving the proximal parts of the infra- basal circlet and variation in the anals. The anals show variation from the normal primitive oblique to slightly advanced position with the primanal not in contact with the BC basal and the distal tip nearly at the radial summit. Variation in the anals is common in other gen- era of the cromyocrinids, such as Ulocrinus as illus- trated by Wright (1927). Preservation of the specimens differs with the for- mation. The two cups from a horizon between the Has- si Kerma Formation and Djenien Member are uncru- shed, replaced with iron oxide, and have a shiny to dull ferruginous brown appearance. Specimens from the El Guelmouna Member are partial crowns (lacking the arms above the proximal secundibrachial or two), abraded, solution etched, slightly distorted from com- paction, and weather a dull gray to gray-brown. The cup from the Mouizeb el Atchane Member is uncru- shed, retains two primibrachials, is abraded, and weathers a polished light gray-tan. The species ranges through the Serpukhovian. Material.—Twenty-two specimens. Holotype (RGM 361 266), paratype 1 (RGM 361 267), paratype 5 (RGM 361 271), paratype 6 (RGM 361 272), and 15 other specimens (lot RGM 290 876) from the marly limestone above DZ12 of the El Guelmouna Member, El Guelmouna Formation, Mississippian (Serpukhov- ian, El), at Djenien, east of Palmeraie de, before the pass, Béchar; Winkler Prins collection. Paratypes 2 and 3 (RGM 361 268; RGM 361 269) found between the Hassi Kerma Formation and Djenien Formation (Tagnana Formation?), Mississippian (Serpukhovian, E2), Tiberbatine Anticline, east side of Oued Guir; Pareyn collection. Paratype 4 (RGM 361 270) from the Mouizeb el Atchane Member, Ain el Mizab For- mation, Mississippian (Serpukhovian, E2), at Djebel Arlal; Legrand-Blain collection. Etymology.—From the Latin vastus, meaning des- olate or vast, in reference to the region wherein the specimens were found. Dicromyocrinus catillus, new species Plate 13, figures 10—12 Diagnosis.—Distinguished by the combination of low bowl shape and fine anastomosing ornament. Description.—Cup low bowl-shaped, width (16.3 mm) more than twice height (6.8 mm), widest at basal apices, very shallow basal invagination, walls in- curved at radial summit, sutures impressed, all plates ornamented with fine low anastomosing irregular ridg- es. Infrabasal circlet 8.1 mm diameter, subhorizontal, not visible in lateral view. Infrabasals 5, slightly wider (4.0 mm) than long (3.8 mm). Basals 5, wider (7.9 mm) than long (5.7 mm), strongly convex transversely and longitudinally, horizontal proximally, vertical dis- tally. Radials 5, width 8.4 mm, length 4.9 mm, strong- ly convex transversely and longitudinally, widest be- tween apices of basals. Radial facets plenary, subhor- izontal, deep, abraded. Anals 3, in primitive arrange- ment. Primanal largest, 5.8 mm long, 3.9 mm wide, in oblique position, pentagonal, adjoins C radial, BC and CD basals, secundanal and tertanal. Secundanal elon- gate, 4.5 mm long, 2.6 mm wide, distal half extends above radial summit. Stem impression circular, 2.5 mm diameter; lumen pentagonal. Remarks.—The cup of Dicromyocrinus catillus n. sp. has been slightly distorted normal to the plane of symmetry, giving it a slightly lop-sided appearance in lateral view. Weathering has obliterated the fine details of the articular facets, which had a transverse ridge, outer ligament pit, and inner muscle areas. Vermiform ornament is not the coarse nodose ornament normally developed on Dicromyocrinus (Webster, 1981). This specimen belongs to the low-bowl lineage of Dicro- myocrinus, Which evolved from the high-bowl form. The low bowl combined with the fine anastomosing ornament distinguishes D. catillus from all other spe- cies of the genus. Material.—Holotype (RGM 361 273), from the up- per part of the Hassi Kerma Formation, Pennsylvanian CARBONIFEROUS (VISEAN—-MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. (Bashkirian), at Oglat Hamia; Legrand-Blain collec- tion. Etymology.—From the Latin catillus, meaning bowl, in reference to the shape of the cup. Dicromyocrinus? invaginatus, new species Plate 13, figures 13-16; Plate 17, figures 9-14 Diagnosis.—Distinguished by the combination of the moderate to deep basal invagination and coarse nodose ornament. Description.—Cup medium flat-bottomed bowl- shaped, incurved slightly at distal tips of radials, mod- erate to deep basal invagination; all cup plates bear coarse nodose ornament; apical pits moderate, sutures moderately impressed. Infrabasal circlet horizontal proximally, forming vertical walls of invagination me- dially, slightly outflaring distally, all within basal in- vagination. Infrabasals 5, dart-shaped, not visible in lateral view. Basals 5, equidimensional, hexagonal or septagonal (BC and CD basals only) where in contact with anals, strongly convex longitudinally, moderately convex transversely, proximal tip in basal invagina- tion, medially form base of cup recurving upward and outflaring distally forming lower half of cup wall. Ra- dials 5, much wider than long, widest very slightly below radial summit, moderately convex longitudinal- ly and transversely, incurving slightly distally, form upper half of cup wall. C radial with shortened side adjacent to anal series; C and D radials not as wide as A, B, and E radials. Radial facet plenary, wide outer ligament area, moderately deep ligament pit, straight transverse ridge, wide muscle areas. Anals 3, primitive or slightly advanced position; primanal largest, hex- agonal, oblique, in contact with C radial, BC and CD basals, D radial, secundanal, and supports tertanal; se- cundanal pentagonal, directly above but not in contact with CD basal, more than half above radial summit, if hexagonal in contact with CD basal; tertanal smallest, pentagonal, two-thirds above radial summit. Arms un- known. Stem facet circular, crenularium half radius. Measurements given in Table 12. Remarks.—The generic assignment of Dicromy- ocrinus? invaginatus n. sp. is tentative because speci- mens have a moderate to deep basal invagination that includes the proximal ends of the basals. As recog- nized by Webster (1981), Dicromyocrinus may have a slightly upflared or slightly invaginated base. No spe- cies assigned to the genus has a moderate to deep basal invagination. None of the other cromyocrinids in the Late Carboniferous with three anals and a moderate to deep basal invagination has ornament. The moderate to deep basal invagination is an advanced evolutionary character. If all of these specimens had two anals, they would possibly be assigned to Ethelocrinus, which has nN _ Table 12.—Measurements in mm for Dicromyocrinus? invagina- tus n. sp. Type Holotype Paratype | Spec. no. (RGM) 361 281 361 282 Cup length 8.7 8.2 Cup width 19.0 16.9 Diameter infrabasal circlet 5 4 Basal length 7.6 6.2 Basal width 8.3 6.2 Radial length 6.4 5.8 Radial width 10 9.2 Diameter stem facet D: 0.9 Length basal invagination | 1.6 a shallow to moderately deep invagination. Variation in the position of the anals suggests mosaic evolution was occurring within D.? invaginatus: three specimens show the primitive position with the secundanal in contact with and directly above the CD basal, whereas two specimens show the slightly advanced position with the secundanal directly above, not in contact with the CD basal. The arms are unknown on the specimen, which is another reason to question the generic as- signment, because Dicromyocrinus has 10. uniserial arms and Ethelocrinus has 16 to 18 biserial arms (Webster, 1981). With future collecting we would not be surprised to see specimens found with three anals and 16 to 18 biserial arms. Both Dicromyocrinus and Ethelocrinus have similar ornament. Dicromyocrinus may be divided into two clades based on fine or coarse ornament. These spec- imens belong to the coarse ornament clade of Dicro- myocrinus as recognized by Webster (1981). All specimens are dorsal cups, lacking the arms and stem, and most ornament has been lost by abrasion or solution. The holotype (RGM 361 281) and one of the non-type (RGM 290 858) specimens have one radial missing. The smallest specimen (RGM 290 856) lacks the anals and three radials. Material.—Five specimens: Holotype (RGM 361 281) and paratypes | and 2 (RGM 361 282, RGM 361 283) and two other specimens (RGM 290 856, RGM 290 858) from the Oued Bel Groun Formation, Penn- sylvanian (Moscovian), Bed M1 (Deleau, 1951), from Béchar-Djerid, immediately south of Béchar; Winkler Prins collection. Etymology.—From the Latin in, into, and vagina, sheath, and refers to the basal invagination. Dicromyocrinus? sp. Plate 13, figures 1—S Remarks.—One disarticulated radial (RGM 361 274, 7.3 mm long, 12.0 mm wide), two BC basals Nn i) (RGM 361 275, 14.2 mm long, 19.8 mm wide: RGM 361 276, 11.4 mm long, 14.3 mm wide), three non- BC basals (RGM 361 277, 11 mm long, 13.0 mm wide; RGM 361 278, 12.2 mm long, 15.4 mm wide; RGM 361 279, 11.1 mm long, 12.7 mm wide), and one partial infrabasal circlet (RGM 361 280, 15.6 mm in diameter); all bearing fine granular ornament that grades into a vermiform ornament are tentatively re- ferred to Dicromyocrinus, based on several criteria. The basals and radials are convex transversely and lon- gitudinally. Radials are widest at the basal apices, nar- row upward and wedge inward with plenary radial fac- ets, as on Aaglaocrinus, Dicromyocrinus, and other cromyocrinids. The infrabasal circlet is upflared gently distally and was barely visible in lateral view, based on the curvature of the basals and radials. Three anals are in the cup in primitive arrangement, which is shown by the presence of an extra facet for the pri- manal articulation on the two BC basals positioned between the radial-tertanal facet, within the radial cir- clet, and the BC-CD basals suture below. The radial facets are plenary, subhorizontal, and deep. The trans- verse ridge is narrow and plenary; the outer ligament pit is shallow, narrow, and 0.7 length of transverse ridge. The outer ligament ridges are narrow, sharp crested, and divided by a narrow shallow furrow. The muscle areas are wide with furrows adoral to the trans- verse ridge. The stem facet is round (5.5 mm diameter) and has a pentalobate lumen. Based on the above fea- tures the cup would have had a medium globe shape. This fits the primitive lineage of Dicromyocrinus with a convex base. Material.—Seven specimens: One radial (RGM 361 274), two BC basals (RGM 361 275, RGM 361 276), three non-BC basals (RGM 361 277—RGM 361 279), and one infrabasal circlet (RGM 361 280) from the lower part of Hassi Kerma Formation, Pennsylvanian (Bashkirian), at Djebel Béchar; Legrand-Blain collec- tion. Genus MOOREOCRINUS Wright and Strimple, 1945 Mooreocrinus glomerosus, new species Plate 13, figures 17—26 Diagnosis. —Distinguished by the combination of less impressed sutures and lower cup with more round- ed base. Description.—Cup medium bowl-shaped, wider (15.0 mm average) than long (8.5 mm), base flat to shallow basal invagination, sutures flush to slightly im- pressed, base walls rounded, distal walls vertical, no ornamentation. Infrabasal circlet subhorizontal with shallow central invagination, 6.1 mm diameter, central BULLETIN 368 stem impression moderately deep. Infrabasals 5, dart- shaped, slightly longer (2.9 mm) than wide (2.6 mm), not visible in lateral view, downflaring proximally, horizontal distally. Basals 5, wider (5.8 mm) than long (5.2 mm), gently convex transversely and longitudi- nally. Radials 5, largest plates in cup, 8.1 mm wide, 5.3 mm long, gently convex transversely and longi- tudinally. Radial facets plenary; transverse ridge nar- row, sharp crested; outer ligament pit 4% length trans- verse ridge, deep, slopes under ridge; outer marginal ridge with transverse ridges and grooves across facet; outer margin shelf moderately wide centrally, crescent- shaped; muscle areas not exposed. Anals large, in primitive position. Primanal largest, 5.6 mm long, 4.0 mm wide, oblique position, adjoined by C radial, BC and CD basals, secundanal, and tertanal. Secundanal elongate, 5 mm long, 3.7 mm wide, distal half above radial summit. Axillary primibrachial wider (8.4 mm) than long (5.2 mm), strongly convex transversely, gently convex longitudinally; primibrachials unequal in length, A longest, C and D second longest, B and E shortest. First secundibrachial wider (4.5 mm) than long (3.2 mm), strongly convex transversely, straight longitudinally. Arms 2 per ray, 10 in total if no branch- ing occurs above primibrachial. Stem round, 2.7 mm (average) diameter; lumen pentagonal. Columnals het- eromorphic, noditaxis N1 at least; latus rounded. Remarks.—The holotype (RGM 361 284) of Moor- eocrinus glomerosus n. sp. 1s distorted slightly and re- tains parts of the D, E, and A ray arms up to the sixth secundibrachial as well as the proximal columnal. Paratype | (RGM 361 285) is a cup with the E, A, and B ray primibrachials and one of the first secun- dibrachials in the E and A rays. In addition it retains the proximal three columnals. Paratype 2 (RGM 361 286) is a crushed partial crown with distorted proximal parts of the arms and three proximal columnals. Para- type 3 (RGM 361 287) is a ferruginous-replaced cup. Mooreocrinus glomerosus lacks the moderately to deeply impressed sutures of M. mendesi (Lane, 1964), M. wilburni Strimple and Watkins (1969) and M. gem- inatus (Trautschold, 1867). It is most similar to M. magdalenensis Strimple, 1975b, but has a relatively lower cup and more rounded base with less of the basals in the vertical cup walls. This is the first report of Mooreocrinus from the Mississippian. It is also the first report of the genus from North Africa. Material.—Four specimens: Holotype (RGM 361 284) and paratype 3 (RGM 361 287), from the El Har- rada Member, Ain el Mizab Formation, Mississippian (Serpukhovian, El), at Cirque de Tagnana (Ued Nark- la); paratypes | and 2, (RGM 361 285, RGM 361 286) from the Mouizeb el Atchane Member, Ain el Mizab CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. Formation, Mississippian (Serpukhovian, E2), at Ra- vine de Djenien; Pareyn collection. Etymology.—Latin, meaning like a ball, referring to the bowl-shaped cup. Genus METACROMYOCRINUS Strimple, 1961 Metacromyocrinus? sp. Plate 15, figures 1—4 Description.—Cup globose, small, length 6.2 mm, width 9.0, all plates with vermiform ornament; apical depressions shallow, deeper at radial-basal apices than basal-infrabasal apices. Infrabasals 5, dart-shaped, length 3.2 mm, width 2.4 mm, gently convex longi- tudinally and transversely, proximally bear 1.2 mm shallow invagination for stem attachment, distally up- flared, visible in lateral view. Basals 5, moderately large, length 3.9 mm, width 4.3 mm, hexagonal, except BC and CD basals septagonal in contact with anals, moderately convex longitudinally and transversely, form maximum width of cup. Radials 5, nearly twice as wide as long, length 3.7 mm, width 4.9 mm, nar- rowing distally, moderately convex longitudinally and transversely, incurved distally. Radial facets plenary, slope gently inward. Anals 3, normal position; pri- manal elongate pentagonal, length 3.7 mm, width 1.9 mm, supporting tertanal on left upper shoulder. Secun- danal directly above posterior basal, length 2.6 mm, width 1.6 mm, distal half above radial summit. Stem and arms unknown. Remarks.—The cup of Metacromyocrinus? sp. is abraded but still shows vestiges of the vermiform or- nament. The arms, tegmen, and stem are not pre- served. Although this is probably a new species, pres- ervation precludes using the specimen for a holotype. It is tentatively assigned to the genus, because of the preservation. Material.—Figured specimen (RGM 290 860) from the Oued Bel Groun Formation, Pennsylvanian (early Moscovian), bed M13 (Deleau, 1951), east? of Oglad Hamia, Kenadza; Winkler Prins collection. Genus MATHERICRINUS Webster, 1981 Remarks.—Termier and Termier (1950) described Parulocrinus wallacei recognizing variation in the cup shape and questioned whether it should be assigned to Ulocrinus or Parulocrinus. Webster (1981) recognized variation in the cup shape from globose to an elongate urn as is common in Mathericrinus, Parulocrinus, and Ulocrinus. Furthermore, some species assigned to each of these three genera show variation in the number of anals from three to two. These three genera are dif- ferentiated by ornamentation on cup plates in Math- ericrinus, the other two genera lacking ornamentation, and Ulocrinus having 10 arms while Parulocrinus has Nn eS) 14 to 18 arms. Some species that have been assigned to each of these genera are based on cups, lacking the arms, so that their generic assignments are uncertain, especially for the unornamented species. Mathericri- nus ranges from the Early to Middle Pennsylvanian and is known from the United States and China. U/- ocrinus ranges from Middle into early Late Pennsyl- vanian and is known only from the United States. Pa- rulocrinus ranges from Middle Pennsylvanian into Early Permian and is known from the United States and Brazil (Webster, 2003). Mathericrinus wallacei (Termier and Termier, 1950), new combination Plate 13, figures 6-9; Plate 14, figures 1-24 Parulocrinus wallacei Termier and Termier, 1950, pp. 100-101, pl. Diagnosis.—Distinguished by fine granular to aligned granular and anastomosing ornament. Description.—Cup flat based medium bowl to elon- gate urn shape, widest at basal apices, fine granular to aligned granular and anastomosing ornament, may have secondary ornament of 2 or 3 narrow ridges re- stricted to distal parts of plates aligned with corre- sponding ridges on adjacent plates but never extending across the central part of the plates, sutures slightly to moderately impressed, plates slightly inflated. Infra- basal circlet relatively large, horizontal proximally, weakly to moderately upflared distally. Infrabasal plates 5, dart shaped, distal tips not visible to barely to obviously visible in lateral view. Basals 5, large, form lower half of cup wall, moderately convex lon- gitudinally and transversely, proximally may be hori- zontal forming part of base of cup or outflaring form- ing base of wall, distally vertical; BC basal heptagonal for contact with primanal on upper left shoulder, all other basals hexagonal. Radials 5, large, wider than long, widest between basal apices, moderately convex longitudinally, moderately convex transversely, verti- cal to slightly inflared distally. Radial facet plenary, slopes inward slightly. Radial facet deep, inner part of outer ligament furrow and outer ligament ridge dentic- ulate; ligament pit shallow; transverse ridge denticu- late on lateral two-thirds; wide triangular muscle areas slope downward toward intermuscular furrow; central pit trifurcate at transverse ridge. Anals 2 or 3, variable positioning, in slightly (tertanal barely in contact with primanal) to strongly advanced (tertanal not in contact with primanal, virtually out of cup) primitive condi- tion. Primanal largest; normally pentagonal in contact with C radial, BC and CD basals, secundanal, and ter- tanal; quadrangular when not in contact with tertanal. Secundanal longer than wide, narrow suture with CD Nn & Table 13.—Measurements in mm for Mathericrinus wallacei n. comb. BULLETIN 368 Spec. no. (RGM) 361 291 361 288 361 289 361 290 316 292 Cup length 9.1 10.1 12.3 11333 14.4 Cup width 17.5 15 1335 19.3 213) Diameter infrabasal circlet 7.8 The 7.8 Oe 11 Basal length 6.7 i) 6.5 8.7 OF Basal width 8.2 7A 7 10 11.3 Radial length BSS) 8 5.4 es 8.9 Radial width 9.2 S22 6.7 10 11.4 Primanal length 5.6 5.6 6 We 7.8 Primanal width 4.7 4 3.6 5 5:9 Stem facet diameter ee 2:5 Dis]: 2 4.1 basal, distal 4 above radial summit. Tertanal smallest, narrow suture with primanal when in contact, other- wise V-shaped proximally, widening distally, mostly to entirely above radial summit. Stem facet slightly impressed, circular, wide crenularium, no areola, pen- talobate axial canal. Arms and stem unknown. Mea- surements given in Table 13. Remarks.—The presence of fine granular to aligned granular and anastomosing ornament distinguishes Mathericrinus wallacei n. comb. from other species assigned to the genus, all of which have different types of ornament. Ornamentation is commonly weathered and completely to mostly lost on specimens of M. wal- lacei. Those specimens with the ornament preserved, however, have variation in the degree of development or lack of the secondary ridges passing across plate boundaries. On several specimens weathering has ac- centuated the aligned ridges extending onto adjacent plates and suturing along plate boundaries. Fracturing along rhombohedral cleavage planes resulted in the loss of parts of some plates on a few specimens. Math- ericrinus wallacei is most similar to M. percultus, which has radial ridge ornament, lacking granular or- nament. Parulocrinus wallacei is transferred to Mathericri- nus because the cup is ornamented; Parulocrinus lacks ornamentation. Loose cup plates assigned to P. wal- lacei by Termier and Termier (1950, pl. 22, figs. 14— 22) are tentatively assigned to M. wallacei. In partic- ular the radials illustrated in figures 16, 19 and 21 may belong to three different taxa, based on drawings of the radial facet. No type was designated by the Ter- miers and we have been unable to locate the original figured specimens. Without seeing the original speci- mens we are unwilling to designate a lectotype. If the Termier specimens are lost, one of the specimens des- ignated | to 6 below could be designated a neotype. The above diagnosis and description are given because the brief comments given in the original description are inadequate to define the species. Variation in the cup shape of Mathericrinus wal- lacei ranges from a flat-based medium bowl (RGM 361 292) with the infrabasal circlet confined to the base to a higher medium globe (RGM 361 288) with the infrabasal circlet gently to moderately upflared and visible in lateral view. Maximum width of the cup shifts from the radial summit or slightly below on the medium-bowl cups to the proximal tip of the radials on the globe-shaped cups. The medium bowl cups are very similar in shape to cups of Dicromy- ocrinus. These cups are assigned to M. wallacei be- cause cups with intermediate shape and bearing the same ornamentation and anals variation are present in the collections. Although the anals are closely similar, they show progressive elimination of the tertanal from the cup, with most specimens having the tertanal resting on the primanal, rarely widely (RGM 361 289; RGM 361 293), commonly narrowly (RGM 361 291; RGM 361 292). The most advanced forms have the tertanal nearly out of the cup (RGM 361 288; RGM 361 290), not in contact with the primanal, and some could al- most be considered to have two anals in the cup be- cause only the proximal tip is below the radial sum- mit. Material.—Twenty-nine specimens. All specimens except specimen 5 are from the Oued el Hamar For- mation, Pennsylvanian (late Bashkirian), Pareyn col- lection. Specimen | (RGM 361 288), specimen 2 (RGM 361 289), specimen 6 (RGM 361 293), speci- men 7 (RGM 361 294) one listed specimen (RGM 361 295), one specimen (RGM 361 298), three specimens (RGM 361 300), two specimens (RGM 361 301), and three specimens (RGM 361 302) from the upper part of Oued el Hamar Formation, Foum ech Cheguiga. Specimen 3 (RGM 361 290) from an undesignated part CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. of the Oued el Hamar Formation, at Chebket Khouabi. Specimen 4 (RGM 361 291), two specimens (RGM 361 299) and five specimens (RGM 361 304) from undesignated part of the Oued el Hamar Formation, south of Teniet Aissa ben Azzi. Specimen 5 (RGM 361 292) from the upper part of the Hassi Kerma Forma- tion, Pennsylvanian (Bashkirian), at Oglat Hamia; Le- grand-Blain collection. Specimen 8 (RGM 361 296), specimen 9 (RGM 361 297), and three specimens (RGM 361 303) from an undesignated part of the Oued el Hamar Formation, on the north flank of Cheb- ket Mennouna. Genus UREOCRINUS Wright and Strimple, 1945 Type species.—Ureocrinus bockschii Geinitz, 1846. Remarks.—The shapes of species of Ureocrinus range from globose to high globe or vase, with the majority of species being a medium globe. The high- globe or vase shape is similar to the high-cone shape of Hydriocrinus. Differences in arm structure and anal arrangement, however, are sufficient to distinguish these taxa. Lane ef al. (2001) removed all Devonian species from Hydriocrinus. See remarks under Hydrio- crinus? confusus for comments on the Late Carbonif- erous species of the genus. Ureocrinus commus, new species Plate 15, figures 9-13 Diagnosis.—Distinguished by the presence of gran- ular to vermiform ornament. Description.—Cup high vase-shaped, base narrow, widest at lowermost tips of radials, distal tips of ra- dials incurved; length 14.8 mm; width 10.7 mm min- imum, 12.1 mm maximum, 11.5 mm average; all plates with granular to vermiform ornament tending to discontinuous to continuous ridges parallel to sides of plates giving appearance of growth rings. Infra- basals large, longer (7.3 mm) than wide (4.2 mm), dart-shaped, straight longitudinally, moderately con- vex transversely; proximal tips horizontal forming base of cup, covered by proximal columnals; distal %4 upflared, forming basal % of cup; C ray infrabasal slighly wider (5.4 mm) than others. Basals 5, longer (7.5 mm) than wide (6.6 mm), moderately convex longitudinally and transversely, 4 hexagonal, 3 with 2 equal upper edges; CD basal hexagonal with elon- gated upper right shoulder in full contact with longest edge of primanal, slightly longer than all basals ex- cept BC basal; BC basal heptagonal, in full contact on upper left shoulder with short edge of radianal, slightly longer than all other basals. Radials 5, slight- ly convex longitudinally, moderately convex trans- versely; A and E wider (6.2 mm) than long (5.5 mm), B and C about as wide as long, D slightly longer than Nn Nn wide; posterior sides of C and D radials project slight- ly higher than, and bottoms of radials not as low as, other radials to accommodate cup anals. C radial hex- agonal, all others pentagonal, narrowing slightly dis- tally. Radial facets poorly preserved, plenary, outer margin slightly convex, transverse ridge straight. An- als 3. Radianal largest, hexagonal, length 5.3 mm, width 3.9 mm. Secundanal small, length uncertain, width 2.2 mm, situated in notch on left shoulder of primanal and right shoulder of D radial, projecting above radial summit. Tertanal pentagonal, not pre- served, space smaller than secundanal, above priman- al, projecting above radial summit. Proximal colum- nal subpentagonal, diameter 3.2 mm, crenulate latus, lumen weakly pentalobate, crenularium narrow, ap- proximately % radius of facet. Arms and tegmen not preserved. Remarks.—The cup of Ureocrinus commus n. sp. 1s well preserved and compares most closely in shape with U. doliolus (Wright, 1936). It differs from all spe- cies of Ureocrinus, however, by having ornamentation. Parts of two primibrachials, lacking the exterior sur- faces, are in the oral cavity. Their position suggests that there were gapes along the radial-primibrachial suture. Material.—Holotype (RGM 290 873) from marly limestone above DZ12, El Guelmouna Member, El Guelmouna Formation, Mississippian (Serpukhovian, E1), at Djenien, east of Palmeraie de, before the pass, Béchar; Winkler Prins collection. Etymology.—From the Greek kommos meaning or- namentation. Cromyocrinid? indeterminate Plate 15, figure 19 Description.—Partial cup, medium cone shape, large (minimum 17 mm long, 27 mm wide); sutures impressed, stitched, plates thick. Infrabasal circlet (5 plates), large (18.2 mm diameter); deep round basal invagination. Distally infrabasals form cup base and walls, visible in lateral view. Basals very wide, out- flaring. Radials large, outflaring, facets plenary. Anals uncertain, minimum 2 1n cup, probably 3, in primitive position. Stem and arms unknown. Remarks.—The fractured and slightly distorted cup of this indeterminate cromyocrinid? is embedded in dark red calcareous shale. The impressed stitched su- tures and thick plates suggest relationship with the cromyocrinids. Most cromyocrinids have bowl- in- stead of cone-shaped cups, and most do not have a deep basal invagination. This specimen may represent a new genus but is of insufficient quality to serve as a holotype. Material.—One cup (RGM 361 305) from the Maz- 56 BULLETIN 368 zer Formation, Mississippian (late Viséan), Mader El Madyid (syncline bed 13, Pareyn, 1961); Pareyn col- lection. Superfamily PERASOCRINACEA Moore and Laudon 1943 Family LAUDONOCRINIDAE Moore and Strimple, 1973 Genus PAIANOCRINUS Strimple, 1951b Paianocrinus? carinatus, new species Plate 15, figures 16-18 Diagnosis.—Distinguished by isotomous arm branching. Description.—Crown elongate (53.6 mm long), flared medially (35.6 mm wide, average), flattened along C-E rays, more than 40 arms. Cup low bowl- shaped, 6.9 mm high, 16.4 mm wide (average), base faintly convex, walls widely flared. Infrabasal circlet small, 5.5 mm diameter, horizontal to faintly upflared. Infrabasals 5, small, 3.6 mm wide, covered proximally by proximal columnal. Basals 5, small, 4.3 mm long, 5.0 mm wide, gently convex transversely, straight lon- gitudinally. Radials 5, dominant plate in cup, 5.4 mm long, 8.7 mm wide, gently convex transversely, straight longitudinally. Radial facets peneplenary, with short narrow deep outer ligament pit and narrow outer margin, remainder not exposed. Anals 3, in primitive oblique position. Primanal equidimensional, 4.2 mm wide and long (may be partly eroded on proximal end); secundanal largest, elongate, 4.7 mm long, 4.1 mm wide, distal half above radial summit; tertanal smallest, proximal 4% below radial summit. Primibra- chials wider (8.2 mm) than long (6.6 mm), moderately convex transversely, gently convex longitudinally, var- iable height with A ray shortest, C and D rays longest, all axillary. First secundibrachials wider (5.2 mm) than long (3.2 mm), strongly convex transversely, straight longitudinally. All higher brachials wider than long, strongly convex or angular transversely. All brachials rectilinear, above secundibrachials bear medial ridge which may grade into a very short blunt spine on distal end. All branchings isotomous on single primibrachial, secundibrachials 3 to 5, tertibrachials 4 or 5, quarti- brachial 8. Last branching in E ray only, may be ab- normal. Normally 8 arms per ray, 41 total. Tegmen unknown. Stem facet round, 3.8 mm diameter; axial canal pentagonal. Remarks.—Width of the radial facet varies with al- most plenary (least peneplenary) facets of the A and B rays, more peneplenary E ray, and most peneplenary D ray of Paianocrinus? carinatus n. sp. The C-ray radial is not preserved. Variation in relative width of the radial facets on a single specimen is highly unusu- al. Generally only slight variation is observed among specimens of the same species. All arm branching is isotomous except in the E ray. The last branching in the E ray is endotomous, occurring only on the adanal side of the adanal half ray. It is possible that this is an abnormal branching or repair of an injury. Classification of this crown is difficult because the cup has affinity with the Laudonocrinidae (possessing peneplenary radial facets, low bowl shape, and three anals); however, all arm branching except in the E ray is isotomous (the laudonocrinids have exotomous branching after the first branchial). The brachials re- semble those of Exocrinus Strimple, 1949, but that ge- nus has plenary radial facets. We assign P.? carinatus to the genus Paianocrinus only tentatively because the shape of the brachials is quite different and is perhaps of generic significance. The brachials of P. durus are thinly rectilinear (wider than long) and broadly convex transversely. Axillary brachials are strongly tumid, bearing distinct protu- berances, with the primibrachials bearing short blunt spines. The rectilinear brachials of P.? carinatus are relatively longer and bear an angular longitudinal me- dian ridge. Axillary brachials lack the protuberance or short spine. The brachials of P. aptus are similar to, but lack the strong tumidity and short spines of P. durus. The family description for the Laudonocrinidae by Moore et al. (in Moore and Teichert, 1978) stated that the arms are endotomous. The arms, however, are known for only three (Anchicrinus, Paianocrinus, Schistocrinus) of the six genera assigned to the family. Under the diagnosis of Paianocrinus, the arms are list- ed (ibid.) as isotomous. Either the diagnosis of the family needs revision, or Paianocrinus does not be- long in the family. The cup of Patanocrinus fits the diagnosis for the Laudonocrinidae, but there is no rec- ognized family that matches both cup and arm mor- phology. We believe that there are major taxonomic problems within several families of the “‘poteriocrinines”’ that involve the arm structure. Genera of the Laudonocrin- idae whose arm structure is known are included within the taxa in need of reevaluation. Because this problem is beyond the scope of this report, we tentatively leave Paianocrinus in the Laudonocrinidae. Paianocrinus has been reported from Chesterian (Late Mississippi- an) strata of North America (Strimple, 1951b; Burdick and Strimple, 1983). Material.—One crown, holotype (RGM 361 306), from the basal part of the Djenien Member, Djenien Formation, Mississippian (early Serpukhovian, E2), at Djebel Béchar; Legrand-Blain collection. Etymology.—From the Latin carina, meaning keel CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. Si, or ridge, referring to the longitudinal ridge along bra- chials. Superfamily ZEACRINITACEA Bassler and Moodey, 1943 Family ZEACRINITIDAE Bassler and Moodey, 1943 Zeacrinitidae indeterminate | Plate 17, figures 32—35 Description.—Cup discoid, 4.3 mm long to end ra- dial facets, 22.2 mm wide; deep (2.5 mm) basal in- vagination 10.2 mm wide; all cup plates with proximal ends in basal invagination. Infrabasals fused, confined to top of basal invagination, covered by proximal col- umnal externally. Basals 5, strongly convex longitu- dinally, concave transversely, longer than wide, distal tips in basal plane to barely upturned; posterior basal slightly longer, truncated distally for reception of sec- ond anal. Radials 5, 6.3 mm long, 11.4 mm wide, strongly convex longitudinally, moderately convex transversely, widely outflared. Radial facet plenary, slope outward at 45°; outer marginal ridge sharp, bounded internally by moderately deep narrow ver- miform-covered outer ligament furrow; outer ligament pit narrow, deep, approximately % facet width; trans- verse ridge full width of facet, vermiform surface, wid- ening toward center, then narrowing across center of outer ligament pit; muscle areas deep, wide, with ridge wider and higher toward center of facet; no central pit, area built up into an oval high continuing as a low intermuscular ridge admedially rather than intermus- cular furrow. Anals 3, primitive position. Primanal pentagonal, adjoining C radial, BC and CD basals, sec- ond and third anals. Second anal hexagonal, longer than wide, distal half extends above radial summit. Tertanal smallest, approximately equidimensional, dis- tal half extending above radial summit. Arms un- known. Stem facet indicates stem round transversely with narrow crenularium. Axial canal round. Remarks.—The cups of the three genera Zeacrinites, Alcimocrinus, and Parazeacrinites of the Zeacrinitidae are indistinguishable from one another. Differences in arm width and number in combination with the tegmen shape are the characters used to distinguish these gen- era. Unfortunately, the Algerian specimens of Zeacrin- itidae indeterminate | lack the arms and cannot be assigned to a genus. The specimens, which are of the same size and show the interiors, may represent a new species. Material.—Two specimens: Figured specimen (RGM 361 307) and unfigured cup (RGM 361 308) are from the El Harrada Member, Ain el Mizab For- mation, Mississippian (Serpukhovian, El), Cirque de Tagnana (Oued Narkla); Pareyn collection. Zeacrinitidae? indeterminate 2 Plate 15, figure 14 Description.—Crown elongate, 52.5 mm long (in- complete), 31.1 mm wide (average), crushed along bi- lateral symmetry plane, more than 40 arms, bearing large tegmen. Cup mostly lost. Radials 5, wider (11.1 mm) than long (6.1 mm), gently convex transversely, faintly convex to straight longitudinally, radial facet plenary, not exposed. Anals 3, large, in primitive ar- rangement. Primanal pentagonal, 7.1 mm long, 6.1 mm wide, positioned oblique, adjoined by C radial, BC and CD basals, secundanal and tertanal, gently convex lon- gitudinally and transversely. Secundanal longer (6.6 mm) than wide (6.0 mm), distal 74 above radial sum- mit. Anal interarea wide with large plates continuing exposure to tertibrach 2. Primibrachial wider (6.2 mm) than long (4.0 mm), gently convex longtudinally and transversely, axillary. Secundibrachial 1 wider (7.4 mm) than long (5.9 mm), moderately convex trans- versely, straight to gently concave longitudinally. Se- cundibrachial 2 axillary. Tertibrachials through quin- quibrachials generally rectilinear, some slightly cune- ate, wider than long proximally becoming more equi- dimensional distally. All branching isotomous with last branching endotomous; branching on tertibrachial 3 or 4, quartibrachial 4 or 5; 6 arms per half ray, 12 per ray, 60 total if branching is the same in all rays. Teg- men plates hexagonal, bulbous center, interconnecting stellate ridges between all plates; shape expanding dis- tally, top not preserved. Remarks.—The infrabasals and basals are not pre- served and weathering has destroyed much of the sur- face ornamentation of the partial crown of Zeacriniti- dae? indeterminate 2. Classification of the specimen is provisional. Most genera assigned to the Zeacrinitidae have large anal plates, a wide anal interarea, endoto- mous branching on all branchings after the first, a large elongate tegmen that expands into a mushroom shape distally (where known), and thin cuneate brachials. This specimen has the large anal plates and wide anal interarea, but the endotomous branching does not com- mence until the third branching. The elongate tegmen of unknown termination may have continued to ex- pand into a mushroom shape. The rectilinear brachials are not typical of most genera assigned to the zeacrin- itids but are known on Zeacrinites, which has a mush- room-shaped tegmen (Moore and Teichert, 1978). A taxonomic review of the Zeacrinitidae is needed to re- solve the significance of the numerous differences in arm types among the genera assigned to the family. Material.—One partial crown (RGM 361 309) from nN ie.) the Ain Mezerelt Member, E] Guelmouna Formation, Mississippian (Serpukhovian, E1) at El Aouidja, sum- mit El Hamar 1; Legrand-Blain collection. Cladid indeterminate | Plate 17, figures 27-28 Description.—Partial cup, lacking C radial and an- als; cup medium bowl shape, base shallow basal con- cavity, fine granular grading into vermiform and aligned ornamentation; plates slightly inflated. Distal tips of infrabasals horizontal, forming base of cup; basals and radials slightly outflaring. Radial facet ple- nary, moderately deep; transverse ridge denticulate, outer ligament furrow wide, moderately deep; liga- ment pit deep: muscle areas wide, upflaring distally. Facets on BC and CD basals indicate 3 anals in prim- itive position. Stem facet roundly pentagonal, im- pressed; lumen pentalobate. Remarks.—At first glance, this specimen of cladid indeterminate | is similar to some cromyocrinids. It lacks the sutured intracup facets of the cromyocrinids, however, and no cromyocrinid has a proximal roundly pentagonal stem. The cup is also similar to several genera of the scytalocrinids. Lacking the stem and arms, the specimen is not suitable to serve as a holo- type and is left in open nomenclature. Material.—One partial cup (RGM 361 310) from the upper part of the Oued el Hamar Formation, Penn- sylvanian (late Bashkirian), at Foum ech Cheguiga; Pareyn collection. Cladid indeterminate 2 Plate 15, figures 5—8 Description.—Intrabasal circlet 4 plates, 3 small, | large, steeply upflared, slightly concave longitudinally, 19.4 mm diameter, base truncated, stem facet round (7.4 mm diameter); lumen roundly pentalobate, large (3 mm diameter). Columnals circular in transverse sec- tion; latus straight, smooth; symplectial articulation. Articulum full width of columnal; crenularium 4 ra- dius; culmina short, coarse, may branch on distal tip. Areola wide, diameter %4 columnal diameter, slightly concave to flat, margins recessed sharply. Perilumen very narrow at outer edge of lumen lobes, wide be- tween lobes; surface nodose where narrow, nodose to irregular culmina where wide. Lumen large, half col- umnal diameter, roundly pentalobate; jugula extended inward, moderately sharply pointed. Noditaxis pattern NI, alternating nodals and internodals. Remarks.—The infrabasal circlet and two of the pluricolumanls of cladid indeterminate 2 are weathered and etched. Ornamentation, if initially present, is lost on the infrabasal circlet, and plates are relatively thin. The stem facet matches the articulum of the pluricol- BULLETIN 368 umnals; thus the specimens are considered to belong to the same species. One holdfast segment judged to belong with these pluricolumnals has the same artic- ular facet with noditaxis pattern of NI and two to five cirri on each nodal. The diameter of the holdfast (4.3 mm) is smaller than that of any of the other pluricol- umnals (7.9 to 12.3 mm diameter). The specimen may represent a stem that tapers distally, it could be a branchlet of a holdfast, or it may be from an immature specimen. The columnals could be assigned to Floricyclus, a genus reported from the Middle Mississippian (Osa- gean) to Late Pennsylvanian (Virgilian) of North America (Moore and Jeffords, 1968), the Tournaisian- Moscovian of Russia (Yeltyschewa and Polyarnaya, 1975; Chernova and Stukalina, 1989), and the Viséan of Poland (Gluchowski, 1981). Chernova and Stukal- ina (1989) also recognized a Late Devonian species from Kazakhstan and a Carboniferous species from Mongolia and China. The Algerian specimens possibly belong to a bloth- rocrinid such as Moscovicrinus or Nebraskacrinus, both of which have large steeply upflaring infrabasal circlets. Nebraskacrinus also has a pentastellate lumen. Material.—Six specimens: One infrabasal circlet (RGM 361 311) and one holdfast segment (RGM 361 312) are from the upper part of the Hassi Kerma For- mation, Pennsylvanian (Bashkirian), at Djebel Béchar; and four pluricolumnals RGM 361 313; lot of three specimens (RGM 361 314) from the lower part of the Hassi Kerma Formation, Pennsylvanian (Bashkirian), at Djebel Béchar; all Legrand-Blain collection. Cladid indeterminate 3 Remarks.—A moderately large partial cup consist- ing of two radials, part of a third radial, one basal, and part of a second basal would have had a bowl shape. All plates bear densely spaced, wavy-aligned, medi- um-coarse, granular ornament, which may grade into short anastomosing ridges. Sutures are impressed and subhorizontal; radial facets are plenary. The ornament differs from all other ornamented taxa described herein by its medium size and dense occurrence on all plates. The cup belongs to an indeterminate cladid and is list- ed for faunal completeness. Material.—Partial cup (RGM 361 351) from upper part of the Akacha-Mazzer formations, Ioucha 18, Mississippian (late Viséan), southeast of Cirque du Meharez el Kébir; Pareyn collection. Cladid indeterminate 4 Plate 17, figures 5—8 Remarks.—A medium-sized basal and radial with nodose to vermiform ornament is strongly convex CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 59 transversely and longitudinally. The cup probably would have been bow] shaped with a basal impression. The basal is encrusted and the nodose ornament is nearly completely lost as a result of solution. This or- nament is very similar to, but coarser and more ver- miform than, that of Dicromyocrinus? sp. These spec- imens probably belong to a cromyocrinid. Material.—One basal and one radial (RGM 361 342) from the upper part of the Hassi Kerma Forma- tion, limestone below level ML171, Pennsylvanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar, Winkler Prins collection. Cladid indeterminate 5 Remarks.—Cladid indeterminate 5 is a small thin- plated basal with granular to vermiform ornament. Material.—One basal (RGM 290 862) from the up- per part of the Hassi Kerma Formation, limestone be- low level ML171, Pennsylvanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar, Winkler Prins collection. Cladid indeterminate 6 Plate 17, figures 15-16 Remarks.—Cladid indeterminate 6 is represented by a large (16 mm wide, 9.7 mm long) pentagonal radial with fine vermiform ornament and an_ externally rounded peneplenary facet. Material.—One radial (RGM 361 345) from the up- per part of the Hassi Kerma Formation, limestone be- low level ML171, Pennsylvanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar, Winkler Prins collection. Cladid indeterminate 7 Plate 17, figures 3, 4 Remarks.—Cladid indeterminate 7 is represented by three small radials (1 mm wide, 5.3 mm long) and one axillary first primibrachial. All plates are deep, strong- ly rounded transversely, and the radial facet is pene- plenary. The exterior surface of the radials is solution etched and the primibrachial retains a small amount of fine vermiform ornament along one side. Material.—Three radials and one primibrachial (RGM 361 346) from the upper part of the Hassi Ker- ma Formation, limestone below level ML171, Penn- sylvanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar, Winkler Prins collec- tion. Subclass FLEXIBILIA Zittel, 1895 Order TAXOCRINIDA Springer, 1913 Taxocrinid indeterminate Plate 16, figure 4 Description.—Infrabasal and basal circlet relatively thick plated, gently upflared with projected CD basal for reception of primanal. Stem impression round, large (8.9 mm diameter), covering infrabasal circlet and proximal *% of basals. Lumen pentalobate. Remarks.—Flexible crinoids are not common in most Pennsylvanian crinoid faunas. Three Pennsylva- nian taxocrinids (Synerocrinus, Enascocrinus, Euony- chocrinus), however, have stem facets covering most of the basals as on this specimen of taxocrinid inde- terminate. Unfortunately, the lack of a more complete specimen prevents generic identification. Material.—One basal circlet (RGM 361 317) from the lower part of the Hassi Kerma Formation, Penn- sylvanian (Bashkirian), at Djebel Béchar; Legrand- Blain collection. Order SAGENOCRINIDA Springer, 1913 Superfamily LECANOCRINACEA Springer, 1913 Family MESPILOCRINIDAE Jaekel, 1918 Genus CIBOLOCRINUS Weller, 1909 Cibolocrinus africanus Strimple and Pareyn, 1982 Cibolocrinus africanus Strimple and Pareyn, 1982, p. 231, fig. 2. Remarks.—Cibolocrinus africanus is based on three moderately well-preserved crowns showing the arms (Strimple and Pareyn, 1982). The genus is known from the Mississippian (Serpukhovian) of Algeria; Pennsyl- vanian (Morrowan) of the United States; Permian (Ar- tinskian) of the Ural Mountains, southwestern United States, and Bolivia; Permian (Wordian) of Sicily; and uncertain Permian horizons in Timor. Material.—Holotype and two paratypes 70.1147 E2, top of Djenien Formation, Mississippian (Serpu- khovian, El), Chebket Djihani; Pareyn collection. Superfamily SAGENOCRINITACEA Roemer, 1854 Family EURYOCRINIDAE Moore and Strimple, ISS Genus AMPHICRINUS Springer, 1906 Amphicrinus formosus, new species Plate 16, figures 11—15 Diagnosis.—Distinguished by the combination of the stem covering the infrabasals and proximal parts of the basals, no ornament, and fewer plates in the interray series. Description.—Crown ovoid bowl-shaped, medium size, length 30.3 mm, width 25.2 mm minimum, 40.8 mm maximum, 33 mm average, plates thick, no or- nament. Cup very low bowl. Infrabasals covered by proximal columnal. Basals 5, small, distal tips project slightly beyond proximal columnal; posterior basal truncated distally for reception of primanal, extends above radial summit. Radials 5, 2.8 mm long, 6.8 mm 60 BULLETIN 368 wide, gently convex longitudinally and transversely, heptagonal, adjoin interray plates on distal shoulders; radial facets plenary, concave transversely. Anals se- ries 1-?. Primibrachials 2, much wider than long, gent- ly convex longitudinally and transversely. First pri- mibrachial 3.7 mm long, 6.7 mm wide; axillary second primibrachial 3.5 mm long, 7.6 mm wide. Interray se- ries variable, |—2—1 or 1—1—1. Secundibrachials 3 or 4 in each half ray, A ray 3 and 4, B ray unknown, C ray 4 and 4, D and E rays 3 and 3. Intrasecundibrachial series variable, 1, 1-1, or 1—-2—1. Number of tertibra- chials varies from 4 to 8, most commonly 6. One ad- ditional branching of quartibrachial 7—11. First 2 branchings isotomous, third branching isotomous or heterotomous, fourth branching heterotomous. Arms incur! distally, free but closely abutting. Patelloid pro- cess poorly developed on secundibrachials, well de- veloped on tertibrachials and higher. Proximal col- umnal elliptical transversely from crushing, 6.5 by 7.4 mm. Proximal columnals very short, symplectial artic- ulation. Remarks.—The holotype of Amphicrinus formosus n. sp. lacks the proximal part of the B ray and is crushed along the A-B interray-D ray plane, with the primanal tilted on edge and other anals covered if pre- sent. The paratype is a partial set of arms. The specimens are assigned to Amphicrinus because they have two primibrachials, interprimibrachials do not touch the basals, intrasecundibrachials are present in small number, and the distal arm branching tends toward heterotomous. Amphicrinus formosus differs from A. scoticus Springer in Wright (1914) and A. tub- erculatus Yakovlev (1961) (typographical error as A. luberculatus Yakolev {[1961]), both of which have the stem completely covering the infrabasals, basals, and proximal tips of the radials. Also, A. formosus has few- er interray plates than A. scoticus, and A. tuberculatus has fine granular ornament. Amphicrinus carbonarius Springer (1920) is based on an imperfect crown with the cup and proximal brachials dislocated and jumbled together. Specimens from the same formation or lat- erally coeval strata as the holotype and identified as A. carbonarius by Laudon (1937) and Strimple (1962) are better preserved partial crowns showing the prox- imal stem completely covering the infrabasals, basals, and proximal tips of the radials. Also, there are many more plates in the anal and interray series than in A. formosus. Two other species, A. divergens Strimple (1940a) and A. simplex Strimple (1940b), both from the Penn- sylvanian, are based on partial crowns with only the cup, primibrachials, and proximal secundibrachials preserved. In these species the number of plates in the anal, interray, and intersecundibrachial series are un- certain, as are arm branching patterns. The proximal columnal does not cover the distal tips of the basals in either species, suggesting relationship with A. for- MOSUS. Material.—Two specimens: Holotype (RGM 361 318) and paratype (RGM 361 319) from the top of the Djenien Formation, Mississippian (Serpukhovian, E2), at Chebket Dyjihani; Pareyn collection. Etymology.—Latin, meaning beautifully formed. Amphicrinus prinsi, new species Plate 16, figures 7-10 Metichthyocrinus sp. Termier and Termier, 1950, p. 92, pl. 218, figs. 46-52. Diagnosis. —Distinguished by the patelloid process developing higher in the secundibrachials, intersecun- dibrachials in contact with the first secundibrachials, five tertibrachials, and asymmetrical first tertibrachials. Description.—Crown ovoid bowl-shaped, medium size (estimated 40 to 50 mm diameter), plates thick, exceedingly fine granular to vermiform ornament poorly preserved. Cup very low bowl. Infrabasals 3, very small, covered by proximal columnal. Basals 5, small, distal tips project slightly beyond proximal col- umnal; posterior basal truncated distally for reception of primanal. Radials 5, 3.8 mm long, 6.4 mm wide, gently convex longitudinally and transversely, heptag- onal, adjoin interray plates on distal shoulders; radial facets plenary, concave transversely. Anals series |-2- 1-1-1-1. Primibrachials 2, much wider than long, gent- ly convex longitudinally and transversely. First pri- mibrachial 3 mm long, 5.5 mm wide; axillary second primibrachial 3.7 mm long, 8.7 mm wide. Interray se- ries variable, 1-2-1-1, 1-2-1-1-1, or 2-2-2-1-1-1. Se- cundibrachials 3 in each half ray in 4 rays preserved. Intrasecundibrachial series 1-1. Number of tertibra- chials varies from 4 to 7, most commonly 6. One ad- ditional branching of quartibrachial 6 in one arm frag- ment preserved. First two branchings isotomous, third branching isotomous or heterotomous, fourth branch- ing heterotomous. Patelloid process poorly developed on secundibrachials, well developed on tertibrachials and higher. Proximal columnal round transversely, 7.3 mm diameter; lumen quinquestellate. Remarks.—The seven specimens of Amphicrinus prinsi n. sp. are two partial crowns and five partial ca- lyx/arm pieces, all showing exterior and interior surfac- es. Two partial distorted crowns, holotype (RGM 361 320) and paratype | (RGM 361 321), were found in two pieces and reconstructed by gluing. The holotype retains the anal series, part of the proximal columnal, and the very small tripartite infrabasals, which are vis- ible on the interior. Paratype 4 (RGM 361 324) has CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 61 distal isotomous arm branching. The internal surface of most specimens shows the original boxwork stereom structure of the ossicles. Variation in the number of in- terray plates and intrasecundibrachials is noted from the interior to the exterior where some paired plates appear to be fused. Description of the species is based on the composite information from the five types. Amphicrinus prinsi n. sp. is similar to A. formosus and likely derived from it. They differ in several mor- phologic features. The patelloid process is more ob- vious and first appears lower in the arms of A. for- mosus than A. prinsi. Intersecundibrachials and the stem facet are smaller in A. formosus. Not all inter- secundibrachials are in contact with the first secundi- brachial in A. formosus, whereas they are well devel- oped in A. prinsi. The number of tertibrachials ranges from five to eight in A. formosus and is consistently five where known in A. prinsi. First tertibrachials are asymmetrical in only the C ray in A. formosus, where- as in A. prinsi all preserved rays show marked asym- metry of first tertibrachials with the outer ray half larg- er than the inner ray half. Material.—Seven specimens: Holotype (RGM 361 320) and paratypes 1-4 (RGM 361 321-—RGM 361 324) and two partial sets of arms (RGM 290 863) are from the upper part of the Hassi Kerma Formation, limestone below level ML171, Pennsylvanian (Bash- kirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar; Winkler Prins collection. Etymology.—Named for C. Winkler Prins, who found the specimens. Sagenocrinid indeterminate | Plate 16, figures 1—3 Description.—Based on 2 radials and 3 basals, plates relatively thin (2.5 mm thick), but large, bearing medium-coarse sharply-pointed granular ornament grading into short sharp-crested irregular ridge orna- ment along proximal edges of plates; formed large bowl-shaped cup with flat or shallow basal invagina- tion, vertical walls, slight impressions or dimples at basal-radial apices, unknown number of anals. Basal, radial and basal-radial facets have shallow excavations for ligamentary articulation and denticulate edges. Basals wider than long, averaging 15.7 mm wide and 11.9 mm long, gently convex transversely, moderately convex longitudinally. Radials wider than long (17.4 mm wide, 10.9 mm long: 18.0 mm wide, 11.7 mm long), gently convex transversely and longitudinally. Radial facets peneplenary, slightly protruded on exte- rior of radial. Transverse ridge sharp-crested, not quite full width of facet; outer ligament pit moderately deep with sharp-crested outer ridge. Inner side of transverse ridge has fine vermiform surface for ligament attach- ment. Lateral ends of transverse ridge to the end of radial facet bear short coarse ridges and grooves nor- mal to ridge. Ligament pit shallow. Remarks.—The plates of sagenocrinid indeterminate 1 are disarticulated, with two of the basals distorted and the third weathered. These plates may have be- longed to a single specimen and, probably, represent a mespilocrinid, such as Cibolocrinus. Material.—Five specimens, two radials, three bas- als: Figured radial (RGM 361 325), figured basal (RGM 361 326), and one radial and two basals (lot RGM 361 327) from the lower part of the Hassi Kerma Fomation, Pennsylvanian (early Bashkirian), at Djebel Béchar; Legrand-Blain collection. Sagenocrinid indeterminate 2 Remarks.—A fragmentary cup consists of the infra- basal circlet, parts of two radials, and 18 distorted proximal columnals. The cup would have been a mod- erately large bowl with a large basal impression in- cluding all of the infrabasals and proximal parts of the basals. Plates are thin and lack ornament. The stem is heteromorphic, and the round proximal columnals are very thin with a narrow crenularium and moderately large pentalobate lumen. The specimen is probably an indeterminate mespilocrinid. Material.—Partial cup (RGM 361 352) from upper part of the Akacha-Mazzer formations, Ioucha 18, Mississippian (late Viséan), southeast of Cirque du Meharez el Kébir; Pareyn Collection. Flexible indeterminate Plate 16, figures 5, 6 Description.—Infrabasal? or basal circlet? large, 15.6 mm by 14.8 mm widths, low, shallow bowl- shaped with shallow basal indentation for 4.9 mm di- ameter circular stem impression, formed by three plates. One of two nearly equal larger plates extended on end of mutual sutures to upwardly incurved mod- erately sharp point, presumably in anal interray. Azy- gous plate in EA interray. Ornament of radiating ridges and grooves on distal half of all plates. Edges of plates with irregular vermiform facet structure on inner half and moderately deep rounded groove along outer half covered by extended lip of outermost surface of plate. Remarks.—An indeterminate flexible specimen shows no trace of smaller plates within the tripartite structure, typical of the infrabasal plate of many flexible crinoids. The sharply extended end of the one larger plate, however, is shaped like the posterior basal of many flexibles and the plate facets are typical of many flexibles. Fused basals are unknown in the flexibles and the azygous plate is normally in the C ray position. It is uncertain if this is an infrabasal plate with an ex- 62 BULLETIN 368 tended end on the one plate, an advanced flexible hav- ing lost the infrabasals with the basals beginning to fuse, an abnormal infrabasal circlet, or an abnormal specimen. Material.—Figured specimen (RGM 361 328) from the Oued Bel Groun Formation, Pennsylvanian (Mos- covian), Bed M1 (Deleau, 1951), from Béchar-Djerid, immediately south of Béchar; Winkler Prins collection. Crinoidea unclassified Remarks.—Disarticulated and fragmentary ossicles from the upper part of the Hassi Kerma Formation, limestone below level ML171, Pennsylvanian (Bash- kirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar, include a variety of unidentifiable specimens. These specimens show that the crinoid fau- na of the Hassi Kerman Formation may be two to three times more diverse than that represented by identified taxa. Caution must be followed, however, in evaluating the diversity because it is likely that some of the in- dividual specimens may be from different parts of a single taxon. For example, the platycrinitid radial and columnals, as well as one of the possible basal circlets, listed under Platycrinites spp. 2 to 5 could represent only one or two species. We believe that these inde- terminate remains contain a minimum of one camerate and five cladids that are undescribed. Specimens are from the Winkler Prins collection. Crinoid indeterminate | Plate 15, figure 15 Remarks.—One medium-sized partial cup shows only the exterior and is embedded in matrix. This spec- imen has a low bowl-shaped cup, tripartite infrabasal circlet consisting of two equally large plates and one small plate, a distally truncated posterior basal, and sub- vertical radials with plenary radial facets. It lacks the B and C radials and the anals. It is uncertain if the spec- imen had more than one anal. It is possibly a lecano- crinid. Material—(RGM 361 336) upper part of the Hassi Kerma Formation, limestone below level ML171, Penn- sylvanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar, Winkler Prins collec- tion. Crinoid indeterminate 2 Remarks.—Two small infrabasal circlets of five plates each and pentalobate axial canals, one (RGM 361 340) with a rounded ridge around the stem facet and the sec- ond (RGM 361 341) with an impressed stem facet. These two specimens may belong to different genera. Material.—Two infrabasal circlets (RGM 361 340 and RGM 361 341) from the upper part of the Hassi Kerma Formation, limestone below level MLI171, Pennsylvanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar, Winkler Prins collection. Crinoids indeterminate Remarks.—Assorted indeterminate tegmen plates, columnals, and other small ossicles (RGM 290 864) are from the upper part of the Hassi Kerma Formation, limestone below level ML171, Pennsylvanian (Bash- kirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar, Winkler Prins collection. Crinoid Columnals Genus OFLORICYCLUS Moore and Jeffords, 1968 ©Floricyclus cf. F. angustimargo Moore and Jeffords, 1968 Plate 17, figures 19, 20 Description.—Pluricolumnal of 2 columnals, 8.7 mm diameter, noditaxis N1 at least. Columnals circular in transverse section, latus straight, symplectial artic- ulation. Articulum full width of columnal; crenularium narrow, ¥,, columnal radius; culmina coarse, very short, unbranched. Areola wide, flat, recesses below crenularium and perilumen. Perilumen very narrow along lobes of lumen, wide between lobes, surface no- dose. Lumen roundly pentalobate, diameter ’, colum- nal diameter. Jugula large, rounded adaxial. Remarks.—This pluricolumnal segment of Floricy- clus cf. F. angustimargo is related to the segments assigned above to Cladid indeterminate 3. Major dif- ferences are the much shorter unbranched culmina, less-recessed areola, and rounded jugula on this spec- imen. It could represent a different section (more or less distal) of the column of Cladid indeterminate 3. The specimen differs from F. angustimargo by having a straight latus with less elongate and more rounded jugula. Moore and Jeffords (1968) reported F. angus- timargo from the Middle Pennsylvanian (Desmoine- sian) strata of Colorado. Material.—Pluricolumnal (RGM 361 315) from the lower part of the Hassi Kerma Formation, Pennsylvanian (Bashkirian), at Djebel Béchar; Legrand-Blain collection. Genus OPLUMMERANTERIS Moore and Jeffords, 1968 ©OPlummeranteris? sp. Plate 17, figures 21—24 Description.—Nodal columnal circular in transverse section, latus very slightly convex. Articulum full width facet. Crenularium wide, 7; radius. Culma full width crenularium, unbranched, no insertions, slight taper adaxial. Areola narrow, flat, recessed slightly be- CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 63 low crenularium and perilumen. Perilumen narrow, no- dose to irregular shaped nodes on surface. Lumen roundly floriform. Jugula short, rounded adaxial. Cirri facets aligned with lobes of lumen, slightly projected. Remarks.—Moore and Jeffords (1968) defined Plummeranteris as having an articulum in which the broad crenularium extended to a weakly developed perilumen about a floriform lumen. Their illustration (pl. 24, fig. 13) of the facet of P. sansaba, however, shows a narrow areola. We tentatively assign two spec- imens to Plummeranteris, noting that they differ from Floricyclus by having a wide crenularium. They may belong to a cromyocrinid. Plummeranteris has been reported from the Middle Pennsylvanian of Texas (Moore and Jeffords, 1968). Material.—Columnal (RGM 361 316) from the lower part of the Hassi Kerma Formation, Pennsyl- vanian (Bashkirian), at Djebel Béchar; Legrand-Blain collection. Columnal (RGM 361 343) from the upper part of the Hassi Kerma Formation, limestone below level ML171, Pennsylvanian (Bashkirian), at Mouizeb El] Atchane, 300 m north of the south gully, Béchar, Winkler Prins collection. Columnal undesignated Plate 17, figures 17, 18 Remarks.—A slender homomorphic pluricolumnal with a medium-width crenularium, unbranched culmina, narrow areola, and large round lumen is partly encrusted with a massive bryozoan that completely encircles part of the specimen. This implies that the bryozoan was at- tached to the stem while the crinoid was living. The articular facet is similar to Cycloscaphus Moore and Jef- fords (1968), which was described as a heteromorphic taxon. It is unknown if the stem was homomorphic dis- tally or proximally of the heteromorphic section. Material.—Pluricolumnal (RGM 290 866) from the upper part of the Hassi Kerma Formation, limestone below level ML171, Pennsylvanian (Bashkirian), at Mouizeb El Atchane, 300 m north of the south gully, Béchar, Winkler Prins collection. Subphylum ECHINOZOA Haeckel in Zittel, 1895 Class ECHINOIDEA Leske, 1778 Subclass PERISCHOECHINOIDEA M’Coy, 1849 Order PALAECHINOIDA Haeckel, 1866 Family PALAECHINIDAE M’Coy, 1849 Genus PALAECHINUS M’Coy, 1844 Palaechinus sp. Plate 17, figure 31 Description.—Partial test medium size, 30.5 mm maximum dimension, 13.3 mm minimum, moderately convex, plates thick. Oculogenital ring monocyclic; genitals wider (3.1 mm) than long (2.5 mm), convex outer side, concave inner side, with 3 or 4 pores; oc- ulars small, 1.7 mm long, 1.8 mm wide, narrowing toward periproct, with single pore. Ambulacral tracks narrow, straight, formed of 2 rows of interlocking plates, each bearing a double pore on the outer side; ambulacral plates much wider than long. Interambu- lacral areas much wider than ambulacral areas, formed of minimum of 6 rows of hexagonal plates increasing in size adorally. Remarks.—This partial corona of Palaechinus sp. consists of three oculars and three genitals of the ocu- logenital ring and adoral parts of three ambulacral tracks and four interambulacral areas. One small frag- mentary plate within the oculogenital ring probably was part of the periproct. All plates are strongly weath- ered and abraded, with loss of all traces of ornament and other morphologic features of the exterior surface. It is uncertain if the corona was fragmented by scay- engers prior to burial or an artifact of weathering. Pa- laechinus is known from the Mississippian of Europe and North America. Material.—Figured specimen (RGM 361 347) from the base of the Ain el Mizab Member, Ain el Mizab Formation, Mississippian (Serpukhovian, El), at Foum es Sba; Pareyn collection. Order CIDAROIDA Claus, 1880 Family ARCHAEOCIDARIDAE M’Coy, 1844 Genus ARCHAEOCIDARIS M’Coy, 1844 Archaeocidaris sp. Plate 17, figures 29, 30 Description.—Interambulacral plate hexagonal, large, 10.5 < 9.4 mm, thin, nodose marginal rim; large central primary tubercle surrounded by scrobicular ring of small secondary tubercles around aureole. Fragment of approximately circular corticate spine shaft 23.6 mm long, 4.2 mm diameter; ornament of aligned nodes along 10 low linear ridges. Remarks.—The interambulacral plate and fragment of a spine shaft of Archaeocidaris sp. are from the same locality, probably from the same species, and thus described together. The interambulacral plate has overgrowths of indeterminate organisms covering some of the scrobicular spines and has been abraded or subjected to solution weathering prior to burial. Or- nament of the spine fragment shows little abrasion or solution weathering. 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Geological Sur- vey of Montana and portions of adjacent territories, Pre- liminary Report (fifth annual) (1871), pp. 373-377. Meek, F.B., and Worthen, A.H. 1865. Descriptions of new crinoidea, etc. from the Carbonifer- ous rocks of Illinois and some of the adjoining states. Proceedings of the Academy of Natural Sciences of Phil- adelphia, vol. 17, no. 3, pp. 155-167. Miller, J.S. 1821. A natural history of the Crinoidea, or lily-shaped animals; with observations on the genera, Asteria, Euryale, Co- matula and Marsupites. Bristol, England, Bryan & Co. 150 pp., numerous unnumbered plates. Miller, S.A. 1883. The American Palaeozoic fossils: a catalogue of the gen- era and species, with names of authors, dates, places of publication, groups of books in which tound, and the et- ymology and signifcation of the words, and an introduc- tion devoted to the stratigraphical geology of the Palaeo- zoic rocks. 2d ed., Cincinnati, Ohio, the author. Echino- dermata, pp. 247-334. 1889. North American geology and paleontology. Cincinnati, Western Methodist Book Concern, 664 pp. 189la. Palaeontology: Advance sheets, Indiana Department of Geology and Natural Resources, 17th Annual Report, pp. 1-103, pls. 1—20. 1891b. North American geology and paleontology, first appen- dix. Cincinnati. Western Methodist Book Concern, pp. 665-718. Miller, S.A., and Gurley, W.F.E. 1890. Description of some new genera and species of Echino- dermata from the Coal Measures and Subcarboniferous rocks of Indiana, Missouri, and Iowa. Privately published, 59 pp., 10 pls. 1895. New and interesting species of Palaeozoic fossils. Hlinois State Museum, Bulletin 7, 89 pp., 5 pls. 1896. New species of Echinodermata and a new crustacean from the Palaeozoic rocks. [linois State Museum, Bulletin 10, 91 pp.. 5 pls. Moore, R.C. 1952. Evolution rates among crinoids. Journal of Paleontology, vol. 26, pp. 338-352. Moore, R.C., ed. 1967. Treatise on Invertebrate Paleontology, Part S, Echinoder- mata |. Geological Society of America and University of Kansas, 2 vols., 650 pp. CARBONIFEROUS (VISEAN—MOSCOVIAN) ECHINODERMS: WEBSTER ET AL. 67 Moore, R.C., and Jeffords, R.M. 1968. Classification and nomenclature of fossil crinoids based on studies of dissociated parts of their columns. Univer- sity of Kansas Paleontological Contributions, Echinoder- mata Article 9, pp. 1-86, 28 pls. Moore, R.C., and Laudon, L.R. 1942. Megaliocrinus, a new camerate crinoid genus from the Morrow Series of northeastern Oklahoma. Denison Uni- versity Bulletin, Journal of the Scientific Laboratories, vol. 37, pp. 67-76. 1943. Evolution and classification of Paleozoic crinoids. Geo- logical Society of America, Special Paper 46, 151 pp. Moore, R.C., and Plummer, F.B. 1938. Upper Carboniferous crinoids from the Morrow Subseries of Arkansas, Oklahoma and Texas. Denison University Bulletin, Journal of the Scientific Laboratories, vol. 32. pp. 209-314, pls. 12-16. Moore, R.C., and Strimple, H.L. 1973. Lower Pennsylvanian (Morrowan) crinoids from Arkan- sas, Oklahoma, and Texas. University of Kansas Paleon- tological Contributions, Article 60, Echinodermata 12, 84 Pp- Moore, R.C., and Teichert, C., eds. 1978. Treatise on Invertebrate Paleontology, Part T, Echinoder- mata 2, Crinoidea. Geological Society of America and University of Kansas, 3 vols., 1026 pp. Pabian, R.K., and Strimple, H.L. 1985. Classification, paleoecology and biostratigraphy of cri- noids from the Stull Shale (Late Pennsylvanian) of Ne- braska, Kansas, and Iowa. University of Nebraska State Museum Bulletin, vol. 11, 81 pp. Pareyn, C. 1961. Les massifs Carboniferes du Sahara Sud-Oranais. Publi- cations du Centre de Recherches Sahariennes, Série Géo- logie, no. 1, vol. 1, pp. 1— 325, vol. 2, pp. 1-244, 28 pls. Phillips, J. 1836. Illustrations of the geology of Yorkshire, or a description of the strata and organic remains. Pt. 2, The Mountain Limestone districts. 2d ed., London, John Murray, pp. 203-208, pls. 3, 4. Pomel, N.A. 1885-1887. Paléontologie ou description des animaux fossiles de |’ Algérie: Zoophytes. Alger, P. Fontana, vol. 2, no. 1, 79 pls. (1885); vol. 2, no. 2, pp. 1-3444 (1887) Roemer, C.F. 1851-1856. Erste Periode, Kohlen-Gebirge. /n Lethaea Geog- nostica, H.G. Bronn, 3d ed.: Stuttgart, E. Schweizerbart, vol. 2, pp. 1-788, 10 pls. Say, T. 1825. On two genera and several species of Crinoidea. Zoolog- ical Journal, vol. 2, no. 7, pp. 311-315. Scotese, C.R., and McKerrow, W.S. 1990, Revised world maps and introduction. /n Palaeozoic pa- laeogeography and biogeography, C.R. Scotese and W.S. McKerrow, eds. The Geological Society Memoir no. 12, pp. 1-21. Sevastopulo, G.D., and Keegan, J.B. 1980. A technique for revealing the stereom structure of fossil crinoids. Palaeontology, vol. 23, no. 4, pp. 749-756. Sieverts-Doreck, H. 1951. Echinodermen aus dem spanischen Ober-Karbon. Palaon- tologiche Zeitschrift, vol. 24, pp. 104-119, 1 pl. Sigler, J.P., White, D., and Kesling, R.V. 1971. Logocrinus brandoni, a new inadunate crinoid from the Middle Devonian Silica Shale of Ohio. University of Michigan Museum of Paleontology, Contributions, vol. 23, no. 13, pp. 213-220. Simms, M.J., and Sevastopulo, G.D. 1993. The origin of articulate crinoids. Palaeontology, vol. 36, pp. 91-109. Springer, F. 1906. Discovery of the disk of Onychocrinus and further re- marks on the Crinoidea Flexibilia. Journal of Geology, vol. 14, pp. 467-523, pls. 4-7. 1913. Crinoidea. /n Zittel, K.A. von, Text-book of paleontology (translated and edited by C.R. Eastman). 2d ed.: London, Macmillan & Co., Ltd., vol. 1, pp. 173-243. 1920. The Crinoidea Flexibilia. Smithsonian Institution Publi- cation 2501, vol. 1, pp. 1-486, vol. 2, pls. A-C, 1-76. Sprinkle, J. 1973. Morphology and evolution of blastozoan echinoderms. Harvard University Museum of Comparative Zoology, Special Publication, 283 pp., 43 pls. Sprinkle, J., and Gutschick, R.C. 1990. Early Mississippian blastoids from western Montana. Bul- letin of the Museum of Comparative Zoology, vol. 152, no. 3, pp. 89-166, 7 pls. Strimple, H.L. 1938. Upper part of the HassiKermathormation Sotnccs 2s «a frecche oye semeiegieta rete det cyctleuspe teense 5, 6. Articular and lateral views of radial; 7, 8, exterior and interior views of basal, *2. RGM 361 342. . Dicromyocrinus? invaginatus new ‘species. Qued' Bel:Groun\ Formation = 2.0.25 45% aes 4 ss wes suc Qe eee ena 9-11. B ray, posterior, and basal, views, 2. Paratype 2, RGM 361 283. 12-14. E ray, posterior, and basal, views, X2. Paratype 1, RGM 361 282. 9». (Gladidiindeterminate:6: ‘Upper partiof the Hass) Kerma) Formation... 2:4 ...: nests se se © ee ei erer ie ene 15, 16. Oral and lateral views of radial, 2. RGM 362 345. . ‘€olumnal!undesignated! Upper part; of! the Hassi Kerma Formation’... cm. . a2 ace oe se cece sie Sree een 17, 18. Articular and lateral views of pluricolumnal, *2. RGM 290 866. . Floricyclus cf. F. angustimargo Moore and Jetfords 1968. Lower part of the Hassi Kerma Formation ............ 19, 20. Articular and lateral views, pluricolumnal, *2.5. RGM 361 315. p plummeranteris.)/Spwrassiy wermayFOrmatlOn\ «ere -qatseyie eresicieieds Cie chen ie raat eects ee ee Cea teen 21, 22. Articular and lateral views, columnal, *2.5. RGM 361 316. Lower part of Hassi Kerma Formation. 23, 24. Articular and lateral views, pluricolumnal, *2. RGM 361 343. Upper part of Hassi Kerma Formation. 25, 26. A ray and posterior views, *2. Paratype 5, RGM 361 271. Cladid! indeterminate Upper part of the Oued (eli Hamar Formation! 2 <2 ece ao) wife ij ot ve ees sieeve eeneieneiineeneue 27, 28. A ray and basal views of partial cup, 2. RGM 361 310. Archaeocidaris sp. OuedielwHamar Formation 4% A -sepere teva ieceeyere ate eie eye cre leis nett tcn= ee) etet ceieuesteatottome malt estes ear eee 29. Lateral view, spine shaft, x2. RGM 361 349. 30. External view of interambulacral plate, *2. RGM 361 348. : Palaechinus sp. Base of the Ain’ el) Mizab Member, Ain el Mizab Formation ........0....5...0-.c055-e0 04056 31. External view of partial corona, X2.1. RGM 361 347. BULLETINS OF AMERICAN PALEONTOLOGY, BULLETIN 368 PLATE 17 INDEX Note: Page numbers for descriptions of genera and species are shown in bold type. Aacocrinus Bowsher W959" . ach anes leased 63, 65 COdMaCrInidS:¥.Jch sh atane tds ces ae el etope ea oy. ey ed accent ee es 45 Goelocrinids 3.2.4 2053 hi. Gad ieys ke ee Ne ck eels 32 Columnalfundesionated! 124.4 . aciscsn cia oe ee 13, 63, 72, 108 Gomatulids 27 wa). ee. ones, eh wees chars, Gata Meee Menta eet 7 Compsocrinina Ubaghs in Moore and Teichert, 1978 ....... 19 CONMOGONES: GF, yi eilsy-s, Se snateices, = de ccs) Sueitehen yehen ole cue cs sites searene 8 Corythocrinidae Strimple and Watkins, 1969 .......... 42, 45 Corythocrinus Wack elOAG eo.) aute au ee eee eee 45 Cosmetocrinuss mark OA ee. osc) ate ave) ences ehonereh eae ca eh eas 48 Cosmetocrinustispir. sa. 2) staid as ese) sane oes 11, 48, 71, 96 Gnnoid Indeterminate 1, <<66 04% 00 5oa cee. 13, 62, 72, 104 Crinoidiindeterminate 20 a). sc css eine erie 135'62, 72 CrinoideaiT.-S- MMillerwliS24 ss neces eeeeeeet a dade ays sene eee 18, 39 Crinoideasunclassifiedsees sn - chenshsrte oko edna ere 62 Erinoidssindeterminate; are cyeecevciscelele cle ushel east eons 13, 62, 72 CHINOLGS 4. oo Pe cos cy cy ke eee em ret Ey ae ee ee ea eye 7, 8, 11-13, 15, 17, 30, 31, 36, 39, 41, 44, 45, 59, 61-63 €rinozoa; Matsamoto; 9295 re ss fe ci sea a) cnere cause cie oneal ane 17 CromyocnnaceayBathern i890 ayn wenatcusnt et acters ehenelnern 49 cromyocrinid (s)......... 11-15, 32, 48, 50, 51, 55, 58, 59, 63 Cromyocrinid? Indeterminate ............... 10, 55, 73, 104 Cromyocrinidac Batherel'890) easy scree ieiee cesieer enone 49 Crotalocrinidsys. Gite casratens fare Worcs sens Radon tna emer Atay egg a 45 Cupressocrinitidae Roemer 18542. ac. se ceo) sear eine 41 Cyathocrinida Moore and Laudon, 1943 ................ 40 GyathocrininaBather 899) 2. - ans cea ese eerie 40, 41, 42 @yathocunitacealBassler 193 Siege ae miei cstere een eee 40 Gy athocnnitidsis a5. cee een icc cheer ene ee ee 17, 40 Cycloscaphus Moore and Jeffords, 1968 ................ 63 Cymbiocrinidae Strimple and Watkins, 1969 ............. 42 Dastanpour Mi asa ee eee 8,15, 17,23, 31h 59168 IDElG aU: Pera ert aie cn etd seed pee es 8,.36, 51, 535,625,65, Delpeyn Gare teeyeocgad saoynetrmevaepeh see ene noe 10, 20, 65 DelvolvésgiUe, uss estes clke = one aera Secu ee eee 39, 65 DendrocrinidaiBather, W899 so a ae cc cseseeyeeeene eee ene 40 dendrocrinids' Jen ne 22 ieee acta en ene 13, 15, 17, 40 DendroctininavBathern i899 sve ess4.n-w-ke se use Nemes eee 40, 42 IDES NESE Gomori oda omae oe boob 65 6 135, 145 1527 DEVONIAN se spelen eee casneape synee ees 11, 23, 27, 31, 445,555.58 Dicromyocrinus Jaekel, 1918 .......... 11, 14, 15, 49-52, 54 DW CQtil USpMe Spee enes ae eee hexchsne ea te ee ener 13, 50, 70, 100 D* granularis: Easton; L962) 625 28. os egeeaue ses Sea ee 50 DMV ASINGATUES Ms SPs -te chee seen ees 14, 50, 51, 70, 100, 108 DPD. medius Moore and Strimple; 1973) 2. ...2,2j2 = cee eee 50 DPD. papillams Worthen; 1882: s.2 ene ie ee ee eee 50 DU VASTUSGT 7 SP=4 east us xe) op sbeneats 11-14, 49, 50, 70, 71, 99, 108 Dicromyocrinus? Sp: an vont tess ae oe 135515595, 7.05100 Diplobathrida Moore and Laudon, 1943 ................ 18 GiSpandS sci-n.y wom eter sbensciajene © chs oreo puciee as Puce eae 15 Disparida Moore and Laudon 1943 .................-- 39 Displodocrinus Websterand ‘Lane, 1987 = 5 22%: fee 19 WjebelvArlaly 3272.2 ay Se [5 i i) vi } By WA i 21 3) 4) 4] \= \e |e i HS 81a i} ih i i 4 4y 4A \A \X \s ! i \ t 4 A : : / i 2 t Sa S3 So S2 S3 Sa 1 NG é 3123) | \ tics) Wie; KHZ SEH 23] W i i H ICN) HIG ~~ 12s] q i , HSS) HIESIG les nN Ht (23) 4 \ i HSS) HISSMH IES) woe 3} E 1 (72) fi i ’ H ISS) HISONNG 8) H IZ 34 H ZS] Hl { " Ni AIS. 7 4 ¥ r H le a HIG SOR 4 t [Ge i Uf ice ¢ ty ‘ Ws! NIG Ae 6 A | 1 Pa VAT 7 | WAN Pa i i { Crvgiss , 2d be Reus dt 7 ANG ANN | Ye} SINGS lic J) oS tLe (f 3 { 1 2 Ve P; qtr arcuatiform qa graciliform GGin-s 7 B graciliform LI qg 5 cusps and denticles showing the precise alignment, *500. The similarity in cusp and denticle cross-sections can be seen in Text-figure 2.3 than Elements | and 2; slightly bowed to inner. In- flection in basal margin beneath posterior margin of cusp. Three denticles. First denticle is narrow and tri- angular, with posterior margin markedly steeper than anterior. Junction of cusp with first denticle lower than that between first and second denticles. Second den- ticle more broadly triangular in lateral profile than ei- ther of other denticles. Denticles symmetrically bicon- vex in cross-section. Third denticle more reclined than first two. All elements have a basal body, which in Element 3 has a hollow, conical interior surface. Incremental growth lines are apparent on the inner surface of the basal body (Text-figs. 2.8, 3.1) The basal bodies of each element remain distinct for almost their entire lengths but are fused into a single mass at the base; it is not certain whether this is a primary or diagenetic feature. An opposed and inverted cusp fragment is attached to the cusp of Element 3 and is of similar morphology; an inverted denticle, which may belong to the same element, is attached to the first denticle of Element 3 (Text-fig. 3). An additional inverted denticle is at- tached to the flank of Element 1, and a third inverted denticle is attached between Elements | and 2 at the anterior end of the third denticles of these two ele- ments. The opposing cusp and denticle fragments are parallel to their counterparts. Microspheres, of phosphatic composition and prob- able bacterial origin, coat many of the element surfaces (Text-fig. 3.2) and were presumably involved in the early post mortem mineralization that resulted in ele- ment fusion. COMPARISON WITH MULTIELEMENT RECONSTRUCTIONS OF CORDYLODUS Elements | and 2 are compressed elements. The only apparatus reconstructions of Cordylodus to have included two morphotypes of compressed element are those of Nicoll (1990) and Ji and Barnes (1994). El- ement | resembles the Pa element of Nicoll (1990) in that the cusp is twisted inwards relative to the posterior process. In turn, Element 2 conforms to the description of Nicoll’s Pb element type in being more symmetrical in cross-section and in being untwisted relative to the posterior margin. As in Nicoll’s material, the cusps of the compressed elements are keeled on their anterior and posterior margins, and the basal cavity extends along the posterior process. Ji and Barnes (1994) also documented variations in the compressed elements and recognized two types based on differences in cusp cur- vature, basal cavity shape and symmetry. In particular, one compressed element morphotype was considered to be more compressed than the other (Ji and Barnes, 1994, p. 31) and, on this basis, the less compressed morphotype may correlate with the Element 1. It is ARCHITECTURE OF CORDYLODUS: SMITH et al. Dag not, however, possible on the basis of their figures to correlate directly with the elements in the cluster. Element 3 is a “rounded” element and is probably equivalent to Nicoll’s (1990) Sb element. The first den- ticle is deflected outwards relative to the cusp and sec- ond denticle; the cusp is biconvex in cross-section and the anterior margin is rounded in its lower part. It cor- responds to one of the two categories of “‘a’’ morpho- type recognized by Ji and Barnes (1994). The two compressed elements within the half ap- paratus of Cordylodus lindstromi are closely compa- rable to the pf and pt elements of the compressed suite in Panderodus described by Sansom et al. (1994). Fur- thermore, the posteriormost pt pair in Panderodus is markedly asymmetrical and the elements have twisted cusps similar to that of Element 1. COMPARATIVE APPARATUS ARCHITECTURE OF CORDYLODUS The construction of apparatus architecture models depends to a large degree on the availability of bed- ding plane assemblages and fused clusters, which can provide three-dimensional data on element disposition once the effects of collapse generated by decay are removed (see Briggs and Williams, 1981; Aldridge er al., 1987; Purnell and Donoghue, 1999 for reviews of the technique). The vast majority of natural assem- blages described to date are of prioniodontid, prion- iodinid and ozarkodinid taxa, with a relatively very small number of coniform taxa represented. Partly be- cause of the relative abundance of natural assemblages and partly because of the presence of associated soft tissues in the Granton Lagerstdtte, ozarkodinids have tended to be used as the Bauplan for complex cono- donts (Aldridge er al., 1987; Purnell and Donoghue, 1998). Ozarkodinid apparatuses contain two pairs of P elements located at the caudal end of the apparatus, with the P, pair rostral to the P, elements (Text-fig. 1.1). The ramiform S elements are oriented with their long caudal (‘posterior’) processes parallel to the long axis of the trunk. M elements flank the battery of S elements but lie, at rest, in an oblique rostro- lateral orientation. The long axes of the S and M el- ements lie at a high angle to those of the P elements, producing an approximately “‘perpendicular” architec- ture. Prioniodontid conodonts are less derived than ozar- kodinids and a smaller number are represented by nat- ural assemblages. Promissum has the best-constrained architecture (Text-fig. 1.2), and it has been suggested that its architecture could be typical of the Prionio- dontida as a whole (Aldridge ef a/., 1995). Four pairs of P elements lie in pairs along the midline, but were located between, and dorsal to, the sinistral and dextral suites of S elements, not caudal to them (Aldridge er al., 1995). The M elements occupy a rostro-lateral po- sition similar to those in ozarkodinids. However, the element morphology of Promissum, whilst potentially typical of the Balognathidae, is not typical of the Prioniodontida as a whole and the small number of available natural assemblages from other prioniodontid taxa suggests that a simpler architecture was charac- teristic of the group. Clusters and associated isolated collections of Oepikodus (Smith, 1991), Paracordy- lodus (Stouge and Bagnoli, 1988, pl. 8, figs. 17a, b; Tolmacheva and Purnell, 2002) and Phragmodus (Re- petski et al., 1998; Barrett, 2000) suggest that the pos- session of four pairs of P elements was not general for prioniodontids, and that the more common architecture for the group may have been more similar to that of ozarkodinids than to Promissum. The only well-constrained architectural model for a coniform taxon is that of Panderodus (Text-fig. 1.3). A large number of fused clusters and a bedding plane assemblage with associated soft tissue from the Wau- kesha Lagerstdtte of Wisconsin, U. S. A., have been used to produce a detailed model for the apparatus of Panderodus (Smith et al., 1987; Sansom et al., 1994). Eight pairs of elements oppose across the midline of the apparatus, and Smith ef al. (1987, p. 100) con- cluded that they must have been arranged in life as parallel and opposed arrays, with either the rostral el- ements more closely spaced or with all of the elements located on an arched support. This arrangement con- trasts markedly with the geometry of S elements in prioniodontids, prioniodinids and ozarkodinids, which are parallel to the midline. Some morphological dif- ferentiation is evident in the elements of Panderodus; Sansom er al. (1994) recognized two principal loca- tional domains—a rostral costate suite and a caudal compressed suite—and all of these elements are par- allel to each other, contrasting with the perpendicular architecture of the ozarkodinids. A third domain oc- cupied by a single symmetrical element lies on the midline. It is immediately tempting to consider the compressed suite as the homologues of the P locations in ozarkodinid apparatuses. However, Panderodus lacks a clearly defined “symmetry transition series” of morphologically intergrading elements, making un- equivocal identification of S homologues difficult. In consequence, it remains a possibility that the two pairs of compressed elements may be homologues not of P elements but of other members of the apparatus. San- som et al. (1994) therefore argued for a conservative approach until supporting evidence was forthcoming. Parenthetically, the concept of symmetry transition has been principally used to differentiate suites of elements rather than to imply locational homology. Neverthe- 28 BULLETIN 369 Text-figure 4 Besselodus arcticus Aldridge, 1982, from the Cincinnatian (Late Ordovician) Aleqatsiaq Fjord Formation of Washington Land. western North Greenland (MGUH 15071) showing a single cluster that split into two during original preparation. 1, 2 Lateral views of sub-cluster “‘a’” (330). 3, 4 Lateral views of sub-cluster ‘*b”” (330). The original plane of fusion between the two sub-clusters lay between the lateral faces of the uppermost elements in Text-figures 4.1 and 4 3. The full array comprises six laterally costate, bilaterally symmetrical non-geniculate elements and one geniculate element, w hich is located at the end of the array. Reproduced with the permission of the Palaeon- tological Association less, some authors have used this concept to infer lo- cation directly, despite the fact that all available evi- dence indicates the contrary—symmetry transition cannot be used as a tool in predicting the sequence of S elements within the ramiform array (Aldridge et al., 1987: Purnell and Donoghue, 1998). It is clear, how- ever, that morphologically intergrading elements do frequently comprise the suite of S elements and, thus, this character provides a predictive tool in distinguish- ing S from M or P elements from elements in other positions (although this tool appears to be inapplicable to prioniodinids; Purnell and von Bitter, 1996). The availability of a well-constrained architectural model for at least one coniform taxon, albeit a rather derived form, enables the appraisal of less well-pre- served and/or less plentiful cluster material of other taxa. A cluster of Besselodus elements (Text-fig. 4) figured by Aldridge (1982) is a single half apparatus with little morphological differentiation. It includes S1X laterally costate, bilaterally symmetrical elements fused by their lateral faces and a single geniculate el- ement at one end of the array. In the absence of ele- ments from the opposing half of the apparatus this cluster could be incorporated into either a pandero- dontid or an ozarkodinid architectural model and there is also no direct control over rostro-caudal polarity in the array. However, Sansom er al. (1994) concluded that the architecture of Besselodus conformed to the ARCHITECTURE OF CORDYLODUS: SMITH et al. 29 panderodontid model on the basis of correlations be- tween elements present in isolated collections and would thus be expected to have a parallel architecture. Critical evidence for the conformity of a given appa- ratus to either the panderodontid or the ramiform-pec- tiniform model thus lies in the geometry of the re- spective halves of the apparatus. In the panderodontid architectural model, elements are arranged along the rostral-caudal axis and are opposed cusp tip to cusp tip, a geometry referred to as parallel-reversed by Landing (1976, p. 1078). Although far from complete, the fused cluster of Cordylodus lindstromi elements may be used to pro- vide some constraints on the apparatus architecture of the genus. Firstly, given the presence of a distinct suite of morphologically intergrading “‘symmetry transi- tion” elements in the apparatus of Cordylodus, we can discriminate a suite of homologues to the S elements of ozarkodinids. This leaves a suite of compressed el- ements that represent either P or M elements. Given that the compressed elements occur paired in the clus- ter, it is likely that they represent a pair of P homo- logues. The occurrence of P homologues aligned in parallel and in juxtaposition to an S homologue indi- cates that Cordylodus possessed overall apparatus ge- ometry that was more similar to panderodontids than to ozarkodinids. Finally, the presence of two com- pressed elements adjacent to each other, with the more asymmetrical morphotype at the end of the array, is consistent with them being locational homologues of the compressed domain in the apparatus architecture of Panderodus. Therefore, it follows that the com- pressed suite in Panderodus is homologous with the P positions in ozarkodinids and their kin. More specifi- cally, we can identify the asymmetrical compressed elements of Panderodus and Cordylodus apparatuses as P, homologues (sensu Purnell et al., 2000), and the more rostral symmetrical elements are P,; homologues. It is tempting to extend from these homologies and identify specific S,, and M locational homologues among the apparatuses of Cordylodus and Pandero- dus. However, because of the architectural differences between the “‘parallel”’ apparatuses of Cordylodus and Panderodus, and the “‘perpendicular’’ apparatuses of prioniodontids and their kin, this is not possible be- cause we have no knowledge of the transformational relationship between the S and M versus P locations in these two fundamentally different architectural types. For instance, the element position immediately adjacent to the putative P, of Cordylodus and Pander- odus could represent either the S,; or S, depending upon the direction in which the left and right halves of the S array have rotated relative to each other (Text- fig. 5). The possibility must also be entertained, how- CUMIN UHM) see ‘Perpendicular’ J elements architecture SS, SS |P elements ‘Parallel! Y= |= \ \s &M architecture | —| |— VY _ elements ees | | aa J 1 Be ne ) P elements Text-figure 5.—Alternative patterns of transformation from the parallel architecture of Cordylodus, Panderodus and Besselodus, to the perpendicular apparatus architecture typical of prioniodontids, prioniodinids and ozarkodinids. The differing methods of transform- ing the parallel architecture are illustrated in the left and right halves of the figure. Given these alternatives, it is not possible to identify specific M and S element homologues in parallel and perpendicular apparatuses, although it is possible to recognize P,; and P, homo- logues and the overall homology of the M and S array of perpen- dicular apparatus architecture with the anterior suite of elements (“costate” or “‘rounded”’) in parallel architectures. ever, that the element position immediately adjacent to the P, in parallel apparatuses represents the M loca- tion, or even another P location. In addition, Dzik (1991) has suggested that the axial (and therefore un- paired) S, location of prioniodontids may be homolo- gous to paired abaxial S, locations in apparatuses with parallel architecture. There is simply insufficient evi- dence to reconcile these competing hypotheses. One direction in which progress can be made is in attempting to resolve the primitive apparatus architec- ture of the earliest euconodonts and its relationship to locational homologies. To do this, parallel and perpen- dicular architectures must be considered with respect to one or more phylogenetic trees. In the absence of a generally accepted hypothesis of relationships for co- nodonts, we have adopted and compared the rival schemes of Sweet (1988) and Dzik (1991) and mapped onto these trees the architectural characteristics of those taxa for which data are available. The differing implications for architectural evolution of the cono- dont apparatus under these schemes can be seen in Text-figure 6. Under the hypothesis of relationships proposed by Sweet (1988), it is not possible to resolve unequivocally whether parallel or perpendicular archi- tectures are representative of the latest common an- cestor of the taxa concerned; both hypotheses are equally likely. However, under the scheme of relation- ships proposed by Dzik (1991), it is possible to resolve unequivocally that the latest common ancestor of all four taxa possessed a parallel, rather than perpendic- ular apparatus architecture. The functional implications of architectural trans- 30 BULLETIN 369 Complex conodonts Cordylodus Besselodus Panderodus Distinct suite of morphologically intergrading elements Parallel apparatus architecture Sweet 1988 Te, Complex conodonts Cordylodus Besselodus Panderodus Distinct suite of morphologically intergrading elements Parallel apparatus architecture HLL LITHT AT Dzik 1991 Text-figure 6.—Inferences of the relative phylogenetic timing of apparatus architectural transformation in taxa for which data are available, based upon the hypotheses of relationships proposed by (1) Sweet (1988) and (2) Dzik (1991). Given that it is not possible to unequivocally infer the relative timing of transformation and/or the primitive apparatus architecture of all the conodonts considered, we have presented the alternative implications of early (ACCTRAN) and late (DELTRAN) transformation. Whilst it is not possible to reconcile primacy between parallel and perpendicular architectures under the scheme proposed by Sweet ( 1988), following Dzik (1991) it is possible to infer unequivocally that parallel architecture is primitive with respect to perpendicular architecture. ARCHITECTURE OF CORDYLODUS: SMITH et al. 31 formation of the apparatus, from parallel to perpendic- ular, are unclear. However, it is clear that morpholog- ical and, by implication, functional differentiation of P from M and S elements preceded the transformation from parallel to perpendicular architectures. Indeed, since morphological differentiation of the apparatus is common to all of the taxa considered, it is possible to conclude that their latest common ancestor possessed an apparatus composed of morphologically distinct el- ement suites. FUTURE DEVELOPMENTS Further resolution of locational homology in prim- itive conodonts will require better quality data in the form of complete natural assemblages. More specifi- cally, these data are required for taxa that can provide insight into the transformational pattern/s through which apparatus architecture was remodelled from the plesiomorphic parallel arrangement to the perpendic- ular architecture that is characteristic of all prionio- dontids currently known from natural assemblages. Nevertheless, the further resolution and refinement of locational homologies and architectures among parallel apparatus-bearing taxa will help to provide a much clearer understanding of plesiomorphic euconodont characteristics. CONCLUSIONS 1) Elements | and 2 are “‘compressed”’ elements. El- ement 1 has an asymmetrical cusp cross-section and is bowed. Element 2 is symmetrical in cross- section and only gently bowed. The presence of two morphotypes of compressed element in the cluster affirms the apparatus reconstructions of Ni- coll (1990) and Ji and Barnes (1994), the only ap- paratus reconstructions of Cordylodus that have in- corporated two morphotypes of compressed ele- ments. 2) The compressed element suite of the Panderodus apparatus (sensu Sansom er al., 1994) may, with some confidence, be considered as a homologue of the compressed elements in Cordylodus. The rounded and compressed elements lay parallel to each other in the apparatus and, together with the closely aligned opposing cusp and denticle tips of the rounded elements, this indicates that Cordylo- dus lindstromi had a parallel panderodontid archi- tecture rather than a perpendicular ozarkodinid type. 3) Consideration of the available natural assemblage material allows a hypothesis to be advanced that elements in the compressed suite of Cordylodus (and Panderodus) may be considered as reasonable candidates for locational homologues of ozarkodi- nid P, and P, elements. 4) Although it is possible to differentiate between ho- mologues of P and S/M elements, it is not possible to identify specific S\-S, and M homologues. 5) The morphological differentiation of elements into P.M and S homologues preceded the topological transformation of the apparatus that produced the characteristic ramiform-pectiniform apparatus ar- chitecture of ozarkodinids, prioniodontids and prioniodinids. 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Geological Sciences University of Missouri-Columbia Columbia, Missouri 65211, U. S. A. AND ANITA G. HARRIS U. S. Geological Survey Reston, Virginia 20192, U.S. A. ABSTRACT eS) Nn A CONODONT-BASED STANDARD REFERENCE SECTION IN CENTRAL NEVADA FOR THE LOWER Ranges of conodonts in stratigraphic sections at five localities in the Monitor and Antelope ranges of central Nevada are used graphically to assemble a standard reference section for the lower Middle Ordovician Whiterockian Series. The base of the series is officially 0.3 m above the base of the Antelope Valley Limestone in the stratotype in Whiterock Canyon (Monitor Range). The top is the level at which Baltoniodus gerdae makes a brief appearance in an exposure of the Copenhagen Formation on the flanks of Hill 8308 in the western Antelope Range. Graphic compilation of the sections considered in this report also indicates that a level correlative with the base of the Whiterockian Series in the stratotype section is 66 m above the base of the Antelope Valley Limestone in its de facto type section on Martin Ridge in the eastern part of the Monitor Range. Ranges, diversity, and the composition of the conodont faunas differ markedly in lithofacies adjacent to the basal boundary of the series; hence we are unable to identify a single conodont species, in a credible developmental sequence, to serve as biological marker of that boundary. INTRODUCTION The Whiterockian Series has been recognized since 1982 as the lower of the two series that compose the North American Middle Ordovician. In the scheme proposed by Ross ef al. (1982) the Whiterockian fol- lows the Lower Ordovician Ibexian Series and pre- cedes the upper Middle Ordovician Mohawkian Series. The Upper Ordovician is the Cincinnatian Series. Conodonts of the Ibexian Series are well known (Ethington and Clark, 1982; Ross et al., 1997), and their distribution has been thoroughly documented in the Ibex District of western Utah, which includes the standard section of that series. In addition, Sweet and Tolbert (1997) have described a section near Shingle Pass in the southern Egan Range, Nevada, that is not only a useful template for the composite Ibexian stan- dard but also serves as the Ibexian reference section in a network of Ordovician sections compiled graph- ically by Sweet (1979; 1984; 1995a, 1995b). In the latter two publications, Sweet describes the progres- sive development of a composite standard that in- cludes rocks assignable to the upper Whiterockian, the Mohawkian, and the Cincinnatian Series. That com- posite is based on conodont range-data from more than 80 sections in central and eastern North America. Although the identity and ranges of conodonts in different parts of the Whiterockian Series are now fair- ly well known (e.g., Ethington and Schumacher, 1969; Bradshaw, 1969; Harris et al., 1979; Stouge, 1984; Bauer, 1987; Ross and Ethington, 1991), no reference section that spans the entire series has been established in the central Nevada type area. Such a section is es- sential to linking the Ibexian and the upper Whiter- ockian-Mohawkian-Cincinnatian standards and thus completing the graphic framework for the North American Ordovician recently summarized by Sweet 36 BULLETIN 369 LOCATION OF CENTRAL NEVADA SECTIONS 39°10' MILES CONTOUR INTERVAL 200 FEET Topography from U.S. Geological Survey Ninemile Peak and Horse Heaven Mountain Provisional 7.5-min. quadrangles, 1990 NEVADA CENTRAL NEVADA SECTIONS @'BEX SHINGLE] AREA 116°20' Text-figure 1.—Location of central Nevada sections considered in this report. WRC = Whiterock Canyon section, BLM = BLM Fence section; MR-I = Martin Ridge South section; MR-II = Martin Ridge North section; AR = Hill 8308 section, Antelope Range. Inset outline map of Nevada also shows approximate location of the Meiklejohn Peak, Ibex Area, and Shingle Pass sections with which central Nevada sections are correlated in this report (1995a, 1995b). It is thus the purpose of this report to describe graphic assembly of a continuous, conodont- based Whiterockian reference standard using infor- mation derived from five stratigraphic sections in cen- tral Nevada, and to show how this composite section might be used to link previously described reference sections for the Ibexian, Mohawkian, and Cincinnatian Series. ACKNOWLEDGMENTS Carrie Wilson and Karen Tyler, Department of Geo- logical Sciences, The Ohio State University, prepared the line drawings that accompany this report. We have also relied heavily on an excellent, unpublished Bach- elors Thesis prepared by Alice W. Spencer in 1984 while she was an undergraduate advisee of Reuben J. Ross, Jr., at the Colorado School of Mines, Golden, Colorado. We also thank Stanley J. Finney and Reuben J. Ross, Jr. for thorough reviews, which have helped improve our report. THE SECTIONS For reasons of structure, access, and facies, we have not identified a single section that spans the entire Whiterockian Series in its type area. Hence, the ref- erence section we describe is a composite, assembled primarily from information at five sites in the Monitor and Antelope ranges of central Nevada (Text-fig. 1) but including important data from the Meiklejohn Peak section of southern Nevada abstracted from reports by Ross and Ethington (1992) and Harris et al. (1979). WHITEROCK CANYON SECTION (WRC) The Whiterock Canyon section, in the Monitor Range, is located and described in recent publications by Ross and Ethington (1991, 1992), whose reports also include diagrams that chart the ranges in the sec- tion of conodonts and other fossils. The WRC section includes the upper 43 m of the Ibexian Ninemile For- mation and the lower 120 m of the superjacent Ante- WHITEROCKIAN REFERENCE SECTION: SWEET et al. 37 lope Valley Limestone. A spike, implanted 0.3 m above the base of the Antelope Valley Limestone for- mally marks the base of the Whiterockian Series. In August 1998, Ethington and Sweet (with the assistance of R. Ripperdan and J. Cooper) collected additional samples from the uppermost Ninemile and the lower few meters of the Antelope Valley. We include in this report information on the conodonts isolated from these samples by Ethington. BLM FENCE SECTION (BLM) This long section is in the NE% sec. 7, T 15 N, R 50 E (Horse Heaven and Ninemile Canyon, Nevada, 7.5-min. quadrangles). The section, is on the east side of Martin Ridge, in the Monitor Range, and roughly parallels an east-west fence established by the Bureau of Land Management. The base of the section is ac- cessible by vehicle on a track along the fence that joins the county road at the foot of Martin Ridge about one mile southeast of the section we here describe as MR- I. The BLM section includes 407 m of Antelope Valley Limestone succeeded by an unmeasured, unsampled and poorly exposed succession of largely clastic rocks representing the Copenhagen Formation. The Antelope Valley was sampled at 5- to 6-m intervals on July 30, 1966 by Ethington and Dietmar Schumacher and re- visited by the same persons in June 1968. The Copen- hagen Formation was not sampled. Conodonts derived from the 47 samples processed are identified here for the first time. MARTIN RIDGE SOUTH SECTION (MR-I) This readily accessible section on the east side of Martin Ridge, is the de facto type section of the An- telope Valley Limestone. It is situated in the center of the SW% of section 6, T 15 N, R 50 E (Horse Heaven Mountain, Nevada, 1:62,500 quadrangle). On the long east-trending ridge up which this section was mea- sured, 342 m of the Antelope Valley Limestone are exposed. The basal contact of the formation is not ex- posed at this locality, but sandy beds poorly exposed in a swale beyond the topmost carbonate beds of the Antelope Valley suggested to Harris et al. (1979) that the section includes the upper contact, with the Co- penhagen Formation. Our studies indicate, on the other hand, that some 71 m of the upper Antelope Valley have probably been cut out along a fault. In August 1975, Anita Harris and Reuben J. Ross, Jr., measured the MR-I section and collected 49 large carbonate samples from it at 5- to 6-m intervals. Some of the conodonts Harris recovered from acid residues of these samples were illustrated in a 1979 report by Harris et al., and they were also made available to Sweet (1995b), who used their ranges in a preliminary graphic attempt to link his Ibexian and Mohawkian composite standards. MARTIN RIDGE NORTH SECTION (MR-II) The short Martin Ridge North section is 3.2 km north of the MR-I section, in the SE% of section 30, T 16 N, R 50 E (Horse Heaven Mountain, Nevada, |: 62,500 quadrangle). In the section at this locality, near the north end of Martin Ridge (Monitor Range), the uppermost beds of the Antelope Valley Limestone are succeeded directly by sandy strata of the Copenhagen Formation. The section, which is a littke more than 16 m thick, was closely sampled in 1975 by Anita G. Harris, and a diagrammatic view of it is given in figure 17 of the 1979 report by Harris er al. Conodonts re- covered from this short section represent a very dif- ferent fauna from that in the uppermost Antelope Val- ley Limestone at the MR-I locality, and this led Harris et al. (1979) to speculate that the upper Antelope Val- ley in MR-I had either been cut out along an unrec- ognized fault, or that “differences in environmental conditions during deposition resulted in two distinct but coeval conodont biofacies.”’ Our studies indicate that the first of these explanations is almost certainly the correct one. HILL 8308 SECTION (AR) The Hill 8308 section, which includes the upper 50 m of the Antelope Valley Limestone, a complete Co- penhagen Formation, and the lowermost beds of the Eureka Quartzite, is situated on the flanks of hill 8308 in the SW% of section 24, T 15 N, R 50 E (Horse Heaven Mountain, Nevada, 1:62,500 quadrangle). The section was measured and sampled for conodonts in 1975, 1978, and 1982 by Anita G. Harris, Alice W. Spencer, and Reuben J. Ross, Jr., assisted in 1982 by J. Webber and R. T. Lierman. A diagrammatic view of the section is given in figure 3 of Harris et al. (1979) and conodonts recovered from the Copenhagen For- mation are the subjects of an excellent, unpublished 1984 Bachelor’s Thesis by Alice W. Spencer. THE CONODONTS In compiling a standard reference section for the Whiterockian Series we have had available to us in- formation on the measured ranges of 134 species-level conodont taxa. However, only the 88 species listed in Table 1 are known from two or more sections and are thus usable in graphic correlation. A majority of the 88 species listed in Table 1 are well-known taxa that have been described and illustrated in recent reports and require no emendation or modification. A few, however, are of especial importance in correlating Whiterockian sections or in characterizing Whiterock- Table 1.—Whiterockian Conodont species.* 38 BULLETIN 369 Index No. Index No. 2 Amorphognathus tvaerensis 72 P. panderi 3 Ansella jemtlandica 73 Parapanderodus asymmetricus 4 A. nevadensis 74 P. emarginatus 5 A. robusta 75 P. striatus 8 Baltoniodus gerdae 76 Paraprioniodus n. sp. 9 B. vartabilis 77 P. costatus 11 Belodina compressa 79 Paroistodus originalis 12 B. monitorensis 80 P. parallelus 16 Cahabagnathus friendsvillensis 81 Periodon aculeatus 17 C. sweeti 82 P. flabellum 18 Chosonodina rigbyi 83 P. gladysi 21 Colaptoconus quadraplicatus 84 P. grandis 22 Cornuodus longibasis 86 Phragmodus flexuosus 24 Dapsilodus mutatus 87 P. inflexus 25 D. variabilis 88 P. undatus 28 Dischidognathus primus 89 Plectodina aculeata 29 Drepanodus arcuatus 90 P. tenuis 31 Drepanoistodus angulensis 9] Polyplacognathus ramosus 32 D. forceps 92 Prattognathus rutriformis 238} D. suberectus 94 Protopanderodus elongatus 35 Eoplacognathus elongatus 95 P. gradatus 36 E. foliaceus-reclinatus 96 P. leonardii 37 Erraticodon balticus 97 P. rectus 40 Fahraeusodus marathonensis 98 P. robustus 42 Histiodella altifrons 99 P. varicostatus 43 H. holodentata 100 Protoprioniodus aranda 44 H. minutiserrata 101 P. nyintii 45 H. serrata 102 P. papilosus 46 H. sinuosa 105 Pteracontiodus alatus 50 Juanognathus jaanussoni 107 P. cryptodens 51 J. variabilis 108 P. gracilis 52 Jumudontus gananda 110 Pygodus anserinus 54 “Loxodus” curvatus 111 P. serrus 55 Microzarkodina flabellum NN 2 Reutterodus andinus of E. & C. 56 Multioistodus subdentatus 1S Scalpellodus latus of Cooper 57 Neomultioistodus compressus 117 Scandodus sp. aff. S. flexuosus 58 Oelandodus costatus 119 “Scandodus” sinuosus 59 Oepikodus communis 121 Scolopodus rex 60 O. evae 122 Spinodus sp. aff. S. spinatus 61 Oistodus lanceolatus 124 Staufferella falcata 62 O. multicorrugatus 127 Thrincodus palaris 64 O. n. sp. 130 Tripodus combsi 67 Paltodus jemtlandicus 132 Walliserodus ethingtoni 69 P. sweeti 134 Yaoxtanognathus abruptus 71 Panderodus gracilis * Gaps in index-no. sequence indicate that the list includes only species used in correlation. ian faunas. We illustrate these species on Plate | and append the following notes about them. Ansella Species of Ansella are represented by A. nevadensis and A. robusta in the upper part of the standard ref- erence section assembled herein, and by A. jemtlandica (Pl. 1, figs. 4—7) in the lower. A. jemtlandica is also known from the lower part of the Antelope Valley Limestone in the Meiklejohn Peak section (MJP) and in early Whiterockian strata in the northern Ranger Mountains of southern Nevada (Ross and Ethington, 1992). Baltoniodus gerdae Baltoniodus gerdae (Bergstrém) (PI. 1, figs. 20, 21). Since 1982, the first occurrence of this species has been used to mark the base of the upper Middle Or- dovician Mohawkian Series, and thus the top of the subjacent Whiterockian Series (Ross et al., 1982). In central Nevada, representatives of B. gerdae have been collected from the AR section and they have also been WHITEROCKIAN REFERENCE SECTION: SWEET et al. 39 reported from high in the Antelope Valley Limestone in the Meiklejohn Peak section of southern Nevada (Harris et al., 1979). Both occurrences are of great importance in effecting the correlations described in this report. Histiodella Species of Histiodella characterize early Whiterock- ian conodont faunas in the Nevada, Utah, and Oklahoma sections considered in this report and we illustrate elements typical of several species in Plate 1. Histiodella altifrons (P\. 1, figs. 23, 24), the earliest Whiterockian species, has smooth-edged albid, car- minate and alate elements that are subtriangular in lat- eral view. The carminate elements of H. minutiserrata have minutely serrated margins; those of H. sinuosa (Pl. 1, fig. 22) have crenulate posterior margins; and comparable elements of H. serrata (Pl. 1, fig. 32) dis- play a distinct cusp, a conspicuously denticulated pos- terior process, and a steeply sloping, denticulated an- terior process. H. holodentata, adequately diagnosed and illustrated by Ethington and Clark (1982, pl. 4, figs. 1, 3, 4, 16), is the youngest Histiodella species recognized thus far in central Nevada. The morphologic progression from Histiodella al- tifrons through H. minutiserrata to H. sinuosa, H. ser- rata, and H. holodentata suggests evolutionary devel- opment and the sequence is repeated in every section for which we currently have information. However, McHargue (1982) demonstrated from study of huge collections of Histiodella from the Joins Formation of south-central Oklahoma that carminate elements with the characters we have used to identify species of the genus appear gradually in populations so that there is considerable stratigraphic overlap between elements with the characters of one species and those with char- acters of its successor. Thus, for example, elements typical of H. minutiserrata appear first in Joins collec- tions dominated by smooth-margined forms like the ones we have recognized as H. altifrons. In like man- ner, anteriorly denticulated elements like those of H. sinuosa appear early in the range of Joins collections dominated by the minutely serrated elements we iden- tify as H. minutiserrata. Because most of our samples from Nevada and Utah contain only a few Histiodella elements, the composition of the populations from which they were drawn cannot be determined. Thus, although Histiodella was a distinctive component of early Whiterockian conodont faunas, we have found it difficult to use the ranges of its species very effectively in graphic correlation. Neomultioistodus compressus The semi-hyaline elements of Neomultioistodus compressus (Pl. 1, figs. 14-19) dominate collections from the Joins and Oil Creek formations of south-cen- tral Oklahoma. They also occur in samples from lower Whiterockian strata in western Utah and eastern Ne- vada, but are not numerous in those samples or in the few from central Nevada that yield them. We illustrate an array of typical specimens from the base of the Antelope Valley Limestone in the WRC section pri- marily as examples of a Whiterockian fauna that is present in central Nevada but only weakly represented there. Oistodus Nn. sp. Several samples from the BLM, Martin Ridge South (MR-I) and Whiterock Canyon sections yield large el- ements (PI. 1, fig. 31) reminiscent of those of Oistodus multicorrugatus, but with a tall, posteriorly-inclined denticle atop the short posterior process. The species represented by these elements is useful in graphic cor- relation, but we defer formal diagnosis to a systematic treatment of Whiterockian conodonts now in prepara- tion. Paraprioniodus n. sp. In their report on Ibexian conodonts, Ethington and Clark (1982) identified this species as Paraprioniodus costatus (Mound) and provided excellent illustrations of components of its multielement apparatus. Studies of large collections from the Joins and Oil Creek for- mations of south-central Oklahoma suggest that P. costatus had a geniculate coniform element in the M position, rather than the dolabrate form Ethington and Clark illustrated. Joins and Oil Creek faunas are cur- rently under study by Jeffrey A. Bauer, of Shawnee State University, who will name, diagnose and illus- trate this new species, so we list it here in open no- menclature. Periodon gladysi Periodon gladysi Albanesi, 1998 (Pl. 1, figs. 1—3), based on specimens from the San Juan Formation of the Argentine Precordillera, has not previously been reported from North America. It is represented in two of the sections (BLM, WRC) considered in this report and is important in correlating those sections. We il- lustrate three specimens from WRC and compare them on Plate 1 with elements of Periodon flabellum (Pl. 1, figs. 8-13) which is known from the BLM, MR-I, and WRC sections in central Nevada, the Meiklejohn Peak (MJP) section in southern Nevada, and from Ordovi- cian strata in the Argentine Precordillera regarded by Albanesi (1998) as of mid- to late Arenigian age. Tripodus combsi (Plate 1, figs. 25-30) From elements in lower Whiterockian strata in west- ern Utah, Ethington and Clark (1982) assembled a 40 BULLETIN 369 WHITEROCKIAN REFERENCE SECTION: SWEET et al. 4] multielement species for which they used the name Tripodus laevis Bradshaw. In 1984, Stouge recognized a species whose apparatus is identical to that of Eth- ington and Clark’s 7. /aevis, but also includes elements like those Bradshaw (1969) named Acodus combsi. We now agree with Stouge’s reconstruction and his choice of “combs” as trivial name; however, because the ap- paratus includes the type form-species of Bradshaw’s Tripodus, we follow the conservative procedure of as- signing the species to Tripodus, rather than Acodus, whose apparatus anatomy is still unkown. ASSEMBLY OF WHITEROCKIAN STANDARD Using the data on stratigraphic ranges of conodonts summarized in Appendix A and the graphic-correla- tion procedures described by Shaw (1964), we have assembled a standard reference section for the Whi- PLATE 1 Figures are digital images of conodont elements from Whiterockian strata in central Nevada. Numbers prefixed by OSU refer to catalog of the Orton Museum of Geology, The Ohio State University, Columbus, Ohio. Numbers prefixed by USNM refer to catalog of the U. S. National Museum, Washington, DC. 1-3 Periodon gladysi Albanesi, 1998 1. Pa element, lateral view, *90. 10 m above base of Antelope Valley Limestone, Whiterock Canyon section. OSU 51151. 2. M element, lateral view, * 102. 10 m above base of Antelope Valley Limestone, Whiterock Canyon section. OSU 51152. 3. Sa element, lateral view, 99. 10 m above base of Antelope Valley Limestone, Whiterock Canyon section. OSU 51153. 4. Sb element, lateral view, *55. 4.5 m above base Antelope Valley Limestone, Whiterock Canyon section. OSU 51154. 5. Sc element, lateral view, *55. 4.5 m above base Antelope Valley Limestone, Whiterock Canyon section. OSU 51155. 6. Sa element, lateral view, «55. 4.5 m above base Antelope Valley Limestone, Whiterock Canyon section. OSU 51156. 7. M element, lateral view, *55. 4.5 m above base Antelope Valley Limestone, Whiterock Canyon section. OSU 51157. «60. Basal 0.15 m Antelope Valley Limestone, Whiterock Canyon section. OSU 51158. «55. Basal 0.15 m Antelope Valley Limestone, Whiterock Canyon section. OSU 51159. «65. Basal 0.15 m Antelope Valley Limestone, Whiterock Canyon section. OSU 51160. «65. Basal 0.15 m Antelope Valley Limestone, Whiterock Canyon section. OSU 51161. 65. Basal 0.15 m Antelope Valley Limestone, Whiterock Canyon section. OSU 51162. 70. Basal 0.15 m Antelope Valley Limestone, Whiterock Canyon section. OSU 51163. 14. Sa element, lateral view, X75. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51164. 15. Sc element, lateral view, X60. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51165. 16. Pa element, lateral view *75. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51166. 17. Pb? element, lateral view, *60. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51167. 18. Sb element, lateral view, *75. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51168. 19. M element, lateral view, 50. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51169. 20. “Amorphognathiform” P element, view of upper surface, 33. 126 m above base of Hill 8308 section, Antelope Range. 21. “Prioniodontiform” P element, lateral view, 44. 126 M above base of Hill 8308 section, Antelope Range. USNM 258550. 22. P element, lateral view, 105. 16.8 m above base of Antelope Valley Limestone, Whiterock Canyon section. OSU 51170. 23. P element, lateral view, 140. 41.5 m above base Ninemile Formation, Whiterock Canyon section. OSU 51171. 24. Sa element, posterior view, * 140. 41.5 m above base Ninemile Formation, Whiterock Canyon section. OSU 51172. 25. Sc element, lateral view, X61. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51173. 26. Sbb element, lateral view, 60. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51174. 27. M element, lateral view, X60. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51175. 28. Sba element, lateral view, X61. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51176. 29. Sa element, posterior view, X70. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51177. 30. P element, lateral view, X62. Basal ledge of Antelope Valley Limestone, Whiterock Canyon section. OSU 51178. 31. Lateral view, 45. 14.5 m above base of Antelope Valley Limestone, Whiterock Canyon section. OSU 51179. 4-7. Ansella jemtlandica (L6fgren, 1978) 8-13. Periodon flabellum (Lindstrém, 1955) 8. M element, lateral view, 9. Pa element, lateral view, 10. Sd element, lateral view, 11. Sb element, lateral view, 12. Sc element, lateral view, 13. Sa element, lateral view, 14-19. Neomultioistodus compressus (Harris and Harris, 1965) 20, 21. Baltoniodus gerdae (Bergstrom, 1971) USNM 258551. [specimen also illustrated as fig. 15, pl. 5, in Harris er al., 1979] [specimen also illustrated as fig. 14, pl. 5, in Harris er al., 1979]. 22. Histiodella sinuosa (Graves and Ellison, 1941) 23, 24. Histiodella altifrons Harris, 1962 25-30. Tripodus combsi (Bradshaw, 1969) 31. Oistodus n. sp. 32. Histiodella serrata Harris, 1962 32. P element, lateral view, 120. 54 m above base Antelope Valley Limestone, Whiterock Canyon section. OSU 51180. 42 BULLETIN 369 terockian Series in central Nevada, the type area. Our procedures are summarized as follows: PRELIMINARY STEPS The BLM section includes the greatest thickness of Antelope Valley Limestone in any of the five sections for which we have information. Further, the BLM sec- tion continues upward to the Copenhagen Formation without any obvious break. Consequently, we chose this section as the base, or reference section, for com- pilation of a standard. Like the BLM section, section MR-II, at the north end of Martin Ridge includes the upper few meters of the Antelope Valley, the Antelope Valley/Copenhagen contact, and the lower few meters of the Copenhagen. Section MR-II is too short to be integrated graphically, but it provides important information on stratigraphi- cally significant conodonts in the boundary interval. Hence, on the assumption that the Antelope Valley/ Copenhagen contact is at the same level (407 m) in both BLM and MR-II, we added range information from MR-II to BLM and used the combined section as the base for further graphic correlations. Ranges of conodonts in the combined section are listed in the column of Appendix A headed BLM+MRII. The graph of Text-figure 2A compares ranges of co- nodont species common to the AR section and the combined BLM+MII section. Although the plotted ar- ray is rather diffuse, a line of correlation (LOC) with a slope of 1.0 and an X-axis intercept of 357 bisects a much narrower array that includes the upper range limits of species 31 (Drepanoistodus angulensis) and 76 (Paraprioniodus n. sp.), the first and last occur- rences of species 36 (Eoplacognathus foliaceus—recli- natus), and the Antelope Valley/Copenhagen contact (plotted as an **x”’). Thus, in the column of Appendix A headed AR+357, we have added 357 m to ranges in the AR column, and, in the column headed CS-1 we have combined BLM+MII and AR ranges. A final step in this preliminary phase of assembly involved graphic comparison of section MR-I with CS-1. This comparison is depicted in Text-figure 2B. Although there was probably little appreciable differ- ence in rock-accumulation rate between MR-I and nearby BLM, the slope coefficient (0.93) of the LOC in Text-figure 2B suggests that rock accumulated slightly more rapidly at MR-I than at BLM. We sus- pect, however, that the slight difference in accumula- tion rate suggested by the lower coefficient 1s more probably attributable to differences in section-mea- surement procedures and placement of samples. In any event, we used the LOC given in Text-figure 2B to determine BLM-equivalent ranges for species identi- fied in MR-I and used these in compiling a composite section that utilizes range information from the three Monitor Range sections and the one in the northern Antelope Range. That composite section is indicated in Appendix A in the column headed WRCS-1. Logically, addition of the Whiterock Canyon section (WRC) would have been the next step in assembly of a Whiterockian standard section, for that section in- cludes the “spike” that officially marks the base of the series (Ross and Ethington, 1991). However, Appendix A indicates that there are substantial differences in the ranges of critical species in the two sections and these differences would influence graphic correlation. For example, in WRC, Histiodella altifrons and Tripodus combsit make their debut at the same level (40 m), whereas in WRCS-1 the first occurrence of 7. combsi precedes that of H. altifrons by 60 m. Also, H. altif- rons has a very short range (10 m) in WRC, but is represented through 45 m of strata in WRCS-1. Ad- ditionally, Ninemile Formation samples below the 40 m level in WRC yield many conodonts of Ibexian stamp that are largely unrepresented in the lower part of WRCS-1. INTEGRATION OF MEIKLEJOHN PEAK SECTION Because of the problems with the Whiterock Can- yon section (WRC) just mentioned, our next step was integration of the section at Meiklejohn Peak, Nevada (MJP), which was established by Ross and Ethington (1991, 1992) as a reference section for the basal part of the Whiterockian Series. In composing the graph of Text-figure 2D, we combined range data for conodonts from the Orthidiella Zone (or Zone L) given by Ross and Ethington (1992) with data from the upper part of the Antelope Valley Limestone given in text-fig. 13 of Harris et al. (1979). This information was then plotted (on the Y axis) against ranges (on the X axis) of the same conodont species in WRCS-1. The LOC of Text- figure 2D lacks control in its mid-portion, but is oth- erwise a credible indication of the relation between Whiterockian strata in these two parts of Nevada. Us- ing the LOC equation, WRCS = 1.12 MJP — 7, we then added information from the Meiklejohn Peak sec- tion to the Whiterock CS. The now more inclusive WRCS-? is in Appendix A. COMPILATION OF WHITEROCK CANYON SECTION With data from Meiklejohn Peak included in WRCS-2, we then plotted range data from the section in Whiterock Canyon (WRC) that includes the basal stratotype of the Whiterockian Series (Ross and Eth- ington, 1991). This plot, shown in Text-figure 2C, re- sults in an array that is quite diffuse and might be interpreted in several ways. The LOC shown in Text- figure 2C is drawn at the interface between segments WHITEROCKIAN REFERENCE SECTION: SWEET et al. base of Copenhagen Fm. 127 50 +16 - oc roa = .-¢ +108 BLM+=.93MRI-7.5 % BLM+MRII=AR+357 eT 0 350 375 400 425m 0 100 200 300 m BLM+MRAII BLM+MRII+AR 120. a zl 73ae © + x = 100 +40 i fe) 100+", a: Zz 46+ 32 5 5 x a < 83 zZ 6) 3 (e) & 50 wi E a5 = 0 aE 100 200 300 400 500 0 50 100 150 200 Wuneagckes cou WHITEROCK CS csu C D Text-figure 2—A, Graphic correlation of Hill 8308 (AR) section with combined BLM and MRII sections. B, Graphic correlation of Martin Ridge South (MR-I) section with composite section BLM+MRII+AR. C, Graphic correlation of Whiterock Canyon section with a Whiterock CS, which is a composite of information from BLM, MRI, MRII, AR, and MJP. D, Graphic correlation of Meiklejohn Peak (MJP) section with the Whiterock CS, a composite of information from BLM, MRI, MRII, and AR. In all graphs, dots represent common range bases: crosses mark common range tops. In A, “x” marks base of Copenhagen Formation; in C, “Ls” mark base and top of brachiopod Zone L projected from MJP section. Numbers near dots and crosses are keyed to species numbers in Table 1. of the graph that include (on the right) a majority of the upper range limits and (on the left) all but one of the plotted first occurrences. In fitting this line we were also influenced by projection from the Meiklejohn Peak section of the lower and upper limits of the Or- thidiella Zone, which has been equated with Zone L of Ross (1951). These limits are shown in Text-figure 2C as “Ls”. Because the spike implanted at 43 m in the WRC section officially marks the base of the Whi- terockian Series (and the Orthidiella Zone), we are now able to project that level into the Whiterockian Composite section (WRCS-3). It is thus 66 csu above 44 BULLETIN 369 the base of that section, or 66 m above the base of the exposed Antelope Valley Limestone in the BLM sec- tion on the east side of Martin Ridge. REGIONAL CORRELATIONS Over the years, conclusions derived from biostrati- graphic studies at other localities in western North America have crystallized into concepts of “basal Whiterockian” that have been widely applied and ac- cepted (e.g., Ross et al., 1997; Sweet and Tolbert, 1997; Fortey and Droser, 1996). Thus, our next step in establishing a Whiterockian standard was to com- pare the Whiterock CS (WRCS-3) graphically with well-established sections in other parts of the country known, or reputed to include strata of Whiterockian age. For this purpose we considered sections in the Ibex District of western Utah (Hintze, 1952; Ross ef al., 1997); the Shingle Pass section in the southern Egan Range of eastern Nevada (Sweet and Tolbert, 1997); a West Spring Creek-Simpson section on the southern flank of the Arbuckle Mountains in south- central Oklahoma; and the Mohawkian-Cincinnatian Composite Standard Section (MC-CS) assembled by Sweet (1995a, 1995b) from sections at more than 80 localities in Midcontinent and eastern United States and including supposed equivalents of the upper Whi- terockian (=Chazyan) in its lower part. CORRELATION WITH MIDCONTINENT COMPOSITE STANDARD In the graph of Text-figure 3A, we compare ranges of conodont species in WRCS-3 with ranges of upper Whiterockian species in the MC-CS. This procedure is identical to the one employed by Sweet (1995b), but, with the better-controlled range data of the present study, yields a LOC described by a slightly different equation. Using MC-CS = 0.658 WRCS + 559, the equation of the LOC drawn in Text-figure 3A, ranges summarized in WRCS-3 were translated into MC-CS values, with the results listed in the column of Appen- dix B headed *.658 + 559 and a new composite sec- tion was assembled from the lowest and highest range values in the two sets. Those values are listed in Ap- pendix B in the column headed MC-CS-1. CORRELATION WITH ARBUCKLE MOUNTAINS SECTION Following creation of a composite section stated in terms of MC-CS, we then compared ranges of cono- dont species assembled in that section graphically with those in a 557-m section (LOK) on the south flank of the Arbuckle Mountains in south-central Oklalhoma that includes the upper part of the West Spring Creek Formation and the Joins and Oil Creek formations. The graph of Text-figure 3B displays results of the comparison of LOK with a MC-CS now augmented by data from Whiterockian sections in central Nevada. The LOC of this graph was fitted to an array of range- limits that are well controlled in both MC-CS and LOK. LOK values were then converted to MC-CS val- ues by use of the equation, MC-CS = 0.41LOK + 507 and a new composite was composed by selecting the lowest and highest range values for each species from the two data sets. That composite is listed in the col- umn of Appendix B headed MC-CS-2. CORRELATION WITH SHINGLE PASS-IBEX AREA COMPOSITE SECTION Finally, in Text-figure 3C we compare MC-CS-2 graphically with data from a regional composite sec- tion (SPIB) that combines range information from sec- tions at Shingle Pass, in eastern Nevada, and the Ibex District of western Utah. This regional composite, giv- en in detail in Appendix 3 of Sweet and Tolbert (1997), is primarily of Ibexian conodont species, but also includes information on the ranges of Whiterock- ian species in its upper part. The well-controlled LOC of Text-figure 3C is described by the equation, MC- CS = 0.52 SPIB + 95, and we used this equation to convert SPIB range values into MC-CS-equivalent ones. MC-CS and converted SPIB values were then combined, as previously, into a new MC-CS-3, which now summarizes range data from central and eastern Nevada, western Utah, south-central Oklahoma and the lower part of a Midcontinent composite section. Ranges in this augmented MC-CS are stated in terms of the Midcontinent Composite Standard Section, which now includes information from the base to the top of the Ordovician System in the United States. CONCLUSIONS In Text-fig. 4, the results of our conodont-based cor- relation of Whiterockian sections in Nevada, Utah, and Oklahoma (Text-fig. 4A) are compared with a dia- grammatic representation of the facies components of the Whiterockian shelf published by Ross er al. (1989) (Text-fig. 4B). In most respects the results of the two studies agree, but they differ in at least two obvious aspects. First, the upper limit of the Orthidiella bra- chiopod Zone, controlled in Text-figure 4A by the sec- tions at Meiklejohn Peak and Whiterock Canyon, pro- jects into the conodont-based framework at a level well above the middle of the Kanosh Shale, at Ibex, and thus to about the mid-point of the supposedly su- perjacent Anomalorthis brachiopod Zone shown in Text-figure 4B. Unfortunately, scaled ranges of the brachiopod species that define the Anomalorthis Zone are not available for sections in our graphically com- piled network, so we cannot evaluate this disparity in WHITEROCKIAN REFERENCE SECTION: SWEET et al. 45 600 CSU 90 550 #134 ae +25 284 500 MC-CS=0.658WRCS+559 + 088 ile n 2 peeost ese weiss oO 450 87 v & ) wi = = 111 2 400 16 195 9 +36 119+ $36 52 33 be 134 °37 350 300 7 800 900 1000 MIDCONTINENT CS cou MIDCONTINENT CS A B 18+ +31 62+ SPIB T T T T 550 600 650 700 750 800 850 MIDCONTINENT CS C Text-figure 3.—Graphic correlation of A, Midcontinent CS and Whiterock CS; B, Arbuckle Mountains (LOK) section, and C, Shingle Pass- Ibex Area composite section with a Midcontinent Composite Section that includes values projected from the Whiterock Composite section. In all three graphs, dots mark common range bases and crosses mark common range tops. Numbers near dots and crosses are keyed to species numbers in Table 1. 46 BULLETIN 369 1000 — Zz ; = a x a = MRP -II oO f= 900 = 5 a fe ze == £E ------ ee et a a ee ive oO a 3 ro) Oo oO 800 5 Antelope z 7) Valley 6 i = 3 3 = s E 5 7004 I a =] a a6 = (o) > ® oO —_ Ot = = aaa [Og |G Sy GS Soe 9 = i) = § < = > S: a4 Zone o 2 ® ea a = Sy od xe) g Ww c £2 D =I & <3 e 8 g a E 600 -- et ----- aw} ----- el Zt----- re c - _- (7p) . z 5 & 3 x 2 2 a MUP a ioe) WRC BLM MRL fe) = 500 -- SW NE LIMIT OF OUTCROP EUREKA QUARTZITE CRYSTAL PEAK DOLOMITE UPPER —— Lee 2 ANTELOPE aa LICHENARIA-OPIKINA Z. oe VALLEY EUREKA QUARTZITE ANTELOPE = (upper) VALLEY ——_ aba Poets LIMESTONE ANTELOPE a VALLEY =F —__ (ORTHIDIELLA NINE Ls MILE > LAF _§ Suc eeieweese JUAB LIMESTONE ZONE FM. a eee a 100 mi B Text-figure 4.—A. Diagrammatic assembly of the sections correlated graphically in this report. Vertical scale is that of the Midcontinent Composite Standard Section (Sweet, 1995b). MJP = Meiklejohn Peak section; AR = Hill 8308 section in Antelope Range; WRC = Whiterock Canyon section; BLM BLM Fence section; MR-II = Martin Ridge North section; MR-I = Martin Ridge South section; SH = Shingle Pass section, southern Egan Range, Nevada; IB = Ibex area composite section, western Utah; Arbuckles = section along Interstate Highway 35 on south flank of Arbuckle Mountains, Carter County, Oklahoma. B. Diagrammatic cross-section of the Whiterockian carbonate shelf reconstructed by Ross et al., 1989 WHITEROCKIAN REFERENCE SECTION: SWEET ef al. 47 results. It may be noted, however, that Anomalorthis occurs within the Orthidiella Zone at a number of places, so both lateral and vertical intergradation of the two biostratigraphic zones is probable. Second, Ross et al. (1997) drew the Ibexian-Whi- terockian boundary in the Ibex District of western Utah at the level 8.5 m below the top of the Wah Wah Limestone in Hintze’s (1952) section J at which bra- chiopods of Zone L (the Paralenorthis—Orthidiella Zone) first appear. Ethington (in Ross ef al., 1997), however, drew the same boundary 2.8 m lower in the Wah Wah, at the level of first appearance of the co- nodont Tripodus combsi (then Tripodus laevis). Sweet and Tolbert (1997) followed the same procedure in de- fining the base of the Whiterockian Series in the Shin- gle Pass section. In the central Nevada sections con- sidered in this report, however, 7. combsi appears for the first time at least 66 m below the projected level of the basal stratotype of the Whiterockian Series, and this certainly limits its usefulness in defining the Whiterockian base regionally. Furthermore, the base of the Orthidiella Zone, controlled in our conodont-based framework by the Meiklejohn Peak and Whiterock Canyon sections, projects to a level well above the base of the Juab Limestone in the Ibexian standard section. Because control on the ranges of conodonts is tighter than on ranges of brachiopods critical to defin- ing the limits of Zone L in the Ibex District, we sus- pect that slight revision in placement of the Ibexian- Whiterockian boundary there may be in order. Finally, we cannot point to a single conodont spe- cies in a credible developmental sequence that will be useful regionally in defining the base of the White- rockian Series, and we suspect that this is also the case with the brachiopod and trilobite species that have been used thus far so effectively in Whiterockian bio- stratigraphy in the western United States. However, in the graphic procedure we have used in assembling a standard section for the Whiterockian Series, it is not necessary to rely on such icons. That is, even though the stratotypical base of the Whiterockian has been established in the Whiterock Canyon section at the lev- el of first occurrence there of the brachiopod Orthi- diella, that same level may be identified with confi- dence in sections that lack Orthidiella 1f those sections can be correlated through graphic comparison of the ranges of the conodont or other species they have in common. REFERENCES CITED Albanesi, G.L. 1998. Taxonomia de conodontes de las secuencias Ordovicicas del Cerro Potrerillo, Precordillera Central de San Juan, R. Argentina. Actas de la Academia Nacional de Ciencias (Cordoba, Argentina), vol. 12, pp. 101—252. Bauer, J.A. 1987. Conodonts and conodont biostratigraphy of the McLish and Tulip Creek Formations (Middle Ordovician) of south-central Oklahoma. Oklahoma Geological Survey Bulletin 141, 58 pp. Bradshaw, L.E. 1969. Conodonts from the Fort Pena Formation (Middle Ordo- vician), Marathon Basin, Texas. Journal of Paleontology, vol. 43, pp. 1137-1168. Ethington, R.L., and Clark, D.L. 1982. Lower and Middle Ordovician conodonts from the Ibex area, western Millard County, Utah. Brigham Young Uni- versity, Geology Studies, vol. 28, pt. 2, pp. 1-155 [imprint 1981]. Ethington, R.L., and Schumacher, D. 1969. Conodonts of the Copenhagen Formation (Middle Ordo- vician) in central Nevada. Journal of Paleontology, vol. 43, pp. 440-484. Fortey, R.A., and Droser, M.L. 1996. Trilobites at the base of the Middle Ordovician, western United States. Journal of Paleontology, vol. 70, pp. 73- 99. Harris, A.G., Bergstrém, S.M., Ethington, R.L., and Ross, R.J., Jr. 1979. Aspects of Middle and Upper Ordovician conodont bio- stratigraphy of carbonate facies in Nevada and southeast California and comparison with some Appalachian suc- cessions. Brigham Young University, Geology Studies, 26, pp. 7-33. Hintze, L.F. 1952. Lower Ordovician trilobites from western Utah and east- ern Nevada. Utah Geological and Mineralogical Survey, Bulletin 48, 249 pp. McHargue, T.R. 1982. Ontogeny, phylogeny, and apparatus reconstruction of the conodont genus Histiodella, Joins Fm., Arbuckle Moun- tains, Oklahoma. Journal of Paleontology, vol. 56, pp. 1410-1433. Ross, R.J., Jr. 1951. Stratigraphy of the Garden City Formation in northeastern Utah, and its trilobite faunas. Peabody Museum Natural History, Bulletin 6, 161 pp. Ross, R.J., Jr., Adler, F.J., Amsden, T.W., Bergstrém, S.M., Carter, C., Churkin, J., Jr., Cressman, E.A., Derby, J.R., Dutro, J.T., Jr., Ethington, R.L., Finney, S.C., Fisher, D.W., Fisher, J.H., Harris, A.G., Hintze, L.F., Ketner, K.B., Kolata, D.L., Landing, E., Neuman, R.B., Sweet, W.C., Pojeta, J., Jr., Potter, A.W., Rader, E.K., Repetski, J.E., Shaver, R.H., Thompson, T.L., and Webers, G.F. 1982. The Ordovician System in the United States of America: Correlation chart and explanatory notes. International Union Geological Sciences, Publication 12, 73 pp. Ross, R.J., Jr., and Ethington, R.L. 1991. Stratotype of Ordovician Whiterock Series, with an ap- pendix on graptolite correlation of the topmost Ibexian by C. E. Mitchell. Palaios, vol. 6, pp. 156-173. 1992. BULLETIN 369 North American Whiterock Series suited for global cor- relation. in Global Perspectives on Ordovician Geology. B.D. Webby and J.R. Laurie, eds. A.A. Balkema, Rotter- dam, Netherlands, pp. 135-152. Ross, R.J., Jr., Hintze, L.F., Ethington, R.L., Miller, J.F., Taylor, 1997. M.E., and Repetski, J.E. The Ibexian, lowermost series in the North American Or- dovician, with a section on Echinoderm Biostratigraphy by James Sprinkle and Thomas E. Guensburg. United States Geological Survey Professional Paper 1579-A, 49 pp. Ross, R.J., Jr., James, N.P., Hintze, L.F., and Poole, F.G. 1989. Architecture and evolution of a Whitrockian (early Mid- dle Ordovician) carbonate platform, Basin Ranges of western U. S. A. in Controls on carbonate platform and basin development. P.D. Crevello, J.L. Wilson, J.-F Sarg, and J.E Read, eds., Society of Economic Paleontologists and Mineralogists, Special Publication 44, pp. 167—185. Shaw, A.B. 1964. Time in Stratigraphy. McGraw-Hill, New York, 365 pp. Stouge, S.S. 1984. Conodonts of the Middle Ordovician Table Head For- mation, western Newfoundland. Fossils and Strata, no. 16, 145 pp. Sweet, W.C. L979" 1984. 1995a. 1995b. Late Ordovician conodonts and biostratigraphy of the western Midcontinent Province. Brigham Young Univer- sity Geology Studies, vol. 26, pt. 3, pp. 45-86. Graphic correlation of upper Middle and Upper Ordovi- cian rocks, North American Midcontinent Province, U. S. A. in Aspects of the Ordovician System. D.L. Bruton, ed., Palaeontological Contributions from the University of Oslo, No. 295, pp. 23-35. A conodont-based composite standard for the North American Ordovician: Progress report. in Ordovician Od- yssey: Short papers for the Seventh International Sym- posium on the Ordovician System. J.D. Cooper, M.L. Droser, and S.C. Finney, eds., Pacific Coast Section So- ciety for Sedimentary Geology (SEPM), Fullerton, CA, pp. 15-20. Graphic assembly of a conodont-based composite stan- dard for the Ordovician System of North America. in Graphic Correlation. K.O. Mann and H.R. Lane, eds., SEPM Society for Sedimentary Geology, Special Publi- cation 53, pp. 139-150. Sweet, W.C., and Tolbert, C.M. 1997. An Ibexian (Lower Ordovician) reference section in the southern Egan Range, Nevada, for a conodont-based chronostratigraphy. United States Geological Survey Pro- fessional Paper 1579-B, pp. 53-84. 49 WHITEROCKIAN REFERENCE SECTION: SWEET et al. 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Sil Appendix B.—Stratigraphic ranges of conodont species (“#" corresponds to “Index No.” in Table 1) in meters, by section. MC-CS = Midcontinent CS; WR-CS = Whiterock CS; LOK = Arbuckles section; SPIB = Shingle Pass-Ibex CS. *See text for discussion of adjustments. # MC-CS WRCS-3 ——*.658+559 MC-CS-1 LOK *0.41+507 MC-CS-2 SPIB 52495 MC-CS-3 2 960-1025 = 518-543 900-916 900-1025 900-1025 900-1025 3 750-806 61-162 606—666 606-806 447-554 690-734 606-806 606-806 4 871-883 233-487 712-879 712-883 712-883 712-883 5 544-830 303-45 1 758-856 544-856 544-856 1219-1322 729-782 544-856 8 876-899 482-487 876-879 876-899 876-899 876-899 9 824-871 464 864 824-871 824-871 824-871 11 942-1015 495-543 885-916 885-1015 885-1015 885-1015 2 773-933 398-502 821-889 773-933 773-933 773-933 16 737-849 400—407 822-827 737-849 737-849 737-849 17 822-885 418-470 834-868 822-885 822-885 822-885 18 218-375 702-806 702-806 385-532 665-725 665-806 1186-1240 712-740 665-806 21 11-49 567-591 567-591 567-591 567-591 22. (-2)-150 558-658 558-658 558-658 318-870 260-547 260-658 24 823-1140 400-518 822-900 822-1140 822-1140 822-1140 25 823-979 403-523 824-903 823-979 823-979 823-979 28 218-375 702-806 702-806 493-532 709-725 702-806 1209-1223 724-731 702-806 29 (-8)-144 554-0654 554-654 0-13 507-512 507-654 420-999 313-614 313-054 31 15-158 569-663 569-663 272-559 619-736 569-736 999-1240 614-740 569-740 32 (-2)-196 558-688 558-688 558-688 381-1092 293-663 293-688 33 750-1276 332-566 777-931 750-1276 750-1276 750-1276 35 834-893 443-461 850-862 834-893 834-893 834-893 36 750-768 393—404 818-825 750-825 750-825 750-825 37 750-850 365—454 799-858 750-858 750-858 1172-1332 704-788 704-858 40 ©2)-192 558-685 558-685 275-557 620-735 558-735 611-1072 413-652 413-735 42 60-105 598-628 598-628 275-298 620-629 598-629 1006-1082 618-658 598-658 43 218-375 702-806 702-806 477-557 703-735 702-806 1216-1240 727-740 702-806 44 61-183 599-679 599-679 280-342 621-647 599-679 1036-1082 634-658 599-679 45 128-257 643-728 643-728 344-364 648—656 643-728 643-728 46 72-215 606-700 606-700 313-544 635-730 606-730 1072-1216 652-727 606—730 50 (—2)-261 558-731 558-731 558-731 879-1082 552-658 552-731 51 (—2)-118 558-637 558-637 188 584 558-637 660-1006 438-618 438-637 32. (-8)-38 554-584 554-584 554-584 753-1006 487-618 487-618 54 218-420 702-835 702-835, 702-835 1209-1229 724-734 702-835 55 0-71 559-606 559-606 559-606 950-974 589-601 559-606 56 308 762 762 268-404 617-673 617-762 1193-1230 715-735 617-762 57 61-386 599-813 599-813 272-557 619-735 599-813 984-1168 607-702 599-813 58 39-55 585-595 585-595 585-595 585-595 59 (—8)-89 554-618 554-618 0-231 507-602 507-618 660-959 438-593 438-618 60 (-2)-55 558-595 558-595 558-595 995 612 558-612 6l (—8)-109 554-631 554-631 554-631 830-911 527-569 527-631 133 647 647 647 647 62 0-390 559-816 559-816 0-557 507-735 507-8 16 853-1082 539-658 507-816 64 6-196 563-688 563-688 563-688 563-688 67 61-151 599-658 599-658 599-658 599-658 69 (—2)-60 558-598 558-598 558-598 558-598 71 822-1263 393-566 818-931 818-1263 818-1263 818-1263 72 822-1261 383-404 811-825 811-1261 811-1261 811-1261 73 0-183 559-679 559-679 6-188 509-584 509-679 739-1082 479-658 479-679 74 12-150 567-658 567-658 279-298 621-629 567-058 600-1082 407-658 407-658 75 (—2)-390 558-816 558-816 0-554 507-734 507-816 353-1223 279-731 279-816 76 247-391 722-816 722-816 410-557 675-735 675-816 675-816 77 288 749 749 275-462 620-696 620-749 1067-1132 650-684 620-749 i) 61-192 599-685 599-685 599-685 896-1044 561-638 561-685 80 G2)=189: 558-650 558-650 558-650 391-974 298-601 298-650 81 757-859 6-540 563-914 563-914 563-914 563-914 82 (—8)-123 554-640 554-640 554-640 554-640 83 61-178 599-676 599-676 599-676 599-676 84 874-1134 510-566 895-931 874-1134 874-1134 874-1134 86 749-892 258-466 729-866 729-892 729-892 1302-1332 772-788 729-892 87 824-962 447-461 853-862 824-962 824-962 824-962 Appendix B—Continued. BULLETIN 369 # MC-CS WRCS-3 88 960-1259 = 502-566 89 807-1009 381-449 90 980-1268 557 91 942-1024 540-549 92 83 407-409 94 (—2)-178 95 (—2)-251 96 (—2)—162 97 0-251 98 61-144 99 750-859 395-45 1 100 (-8)-71 66-178 101 0-12 102 60-109 105 750-913 395-461 107 247-291 108 332-407 110 828-859 409-447 111 762-828 402-407 112 11-44 115 0-79 117 15-49 119 126-394 121 (—2)-60 122 952-976 466 124 849-1152 386-488 127 805-885 397-434 130 (—8)—242 132 (—1)-165 134 972-1114 540-557 *.658+559 MC-CS-1 LOK *0.414+507 MC-CS-2 SPIB 52-695 MC-CS-3 889-931 889-1259 889-1259 889-1259 810-854 807-1009 807-1009 807-1009 926 926-1268 926-1268 926-1268 914-920 914-1024 914-1024 914-1024 827-828 827-834 827-834 827-834 558-676 558-676 558-676 794-89 | 508-558 508-676 558-724 558-724 188-557 584-735 558-735 739-1210 479-724 479-735 558-666 558-666 558-666 640-1059 428-646 428-666 559-724 559-724 559-724 559-724 599-654 599-654 599-654 599-654 819-862 750-862 750-862 750-862 554-606 554-606 188-231 584-602 554-606 884-999 554-614 554-614 602-676 602-676 602-676 602-676 559-567 559-567 559-567 896-1006 561-618 559-618 598-631 596-631 596-63 1 903 565 565-631 819-862 750-913 750-913 750-913 722-750 722-750 272-547 619-731 619-750 905-1161 566-699 566-750 777-827 777-827 441-554 688-734 688-827 1181-1216 709-727 688-827 828-853 828-859 828-859 828-859 824-827 762-828 762-828 762-828 566-588 566-588 566-588 758-944 489-586 489-588 559-611 559-611 559-611 559-611 569-591 569-591 206 So 569-591 240-888 220-557 220-591 642-816 642-8 16 349-557 650-735 642-816 642-816 558-598 558-598 558-598 318-691 260—454 260-598 866 866-976 866-976 866-976 813-880 813-1152 813-1152 813-1152 820-845 805-885 805-885 805-885 554-718 554-718 268-544 617-730 554-730 928-1082 578-658 554-730 558-668 558-668 558-668 548-800 380-511 380-668 914-926 914-1114 914-1114 914-1114 ST. PETER—GLENWOOD CONODONTS: WITZKE AND METZGER ORDOVICIAN CONODONTS AND STRATIGRAPHY OF THE ST. PETER SANDSTONE AND GLENWOOD SHALE, CENTRAL UNITED STATES BRIAN J. WITZKE Iowa Dept. Natural Resources, Geological Survey Iowa City, Iowa 52242, U.S. A. AND RONALD A. METZGER Southwestern Oregon Community College Coos Bay, Oregon 97420, U.S. A. ABSTRACT The age of the St. Peter Sandstone in the central and northern Midcontinent has long been considered equivocal because of the general absence of biostratigraphically useful fossils. Conodonts recovered from the St. Peter Sandstone in Iowa, Minnesota, Nebraska, and Kansas for this study help place some age constraints on this renowned formation in its northern and western extent. Faunas from the lower St. Peter include Phragmodus flexuosus, Cahabagnathus sp., and Leptochirognathus sp., and a late Whiterockian (Chazyan) correlation is indicated. Juvenile or immature elements of P. flexwosus from these collections show morphologies trending toward P. cognitus and P. inflexus, and paedomorphic derivation of these latter species is proposed. Diverse assemblages of hyaline forms also occur in the St. Peter strata (Erismodus spp., Erraticodon sp., Curtognathus sp., Coleodus sp., Archeognathus sp., Stereoconus sp., others) along with various albid elements (Plectodina sp., Eoplacognathus sp., others). The overlying Glenwood Shale contains abundant conodonts dominated by Phragmodus cognitus, Erismodus sp., and Chirognathus duodactylus, and the fauna is interpreted as an early Mohawkian (Blackriveran) association. Certain thin shale units in the St. Peter-Glenwood succession represent condensed intervals, in part reflected by their exceptionally high conodont abundances. Some organic-rich phosphatic shale units in the lower St. Peter of western Iowa have produced equivalent yields of tens of thousands of conodonts per kilogram, and many Glenwood Shale samples yield thousands of conodonts per kilogram. Previous depositional models have proposed that the St. Peter is primarily a succession of littoral and nearshore facies forming a broadly diachronous transgressive sheet sand. However, broad-scale diachroneity cannot be demonstrated with available bio- stratigraphic control. The recognition of condensed marine shale units, phosphorites, ironstones, and pyritic hardgrounds in the western facies tract of the St. Peter Sandstone has necessitated a re-evaluation of previous regional models of St. Peter deposition. The St. Peter is interpreted to be a composite stratigraphic interval deposited during a succession of transgressive-regressive sedimentary cycles. Transgressive episodes in some cycles were marked by offshore sediment condensation or starvation within a stratified seaway. Nn WwW INTRODUCTION DISCOVERY OF ST. PETER CONODONTS The St. Peter Sandstone is a widespread sandstone- dominated Ordovician stratigraphic unit recognized across much of the central United States. Because the St. Peter is bounded below by a major cratonic un- conformity of unknown duration (Sauk-Tippecanoe unconformity of Sloss, 1963) and because it failed to produce any biostratigraphically useful fossils after many decades of study, its age was long considered equivocal. In the 1970s indigenous conodonts were found in the type area of the St. Peter (Olsen, 1976). Clark and Miller (1971) and Grether and Clark (1980) recovered conodonts from the basal Readstown Mem- ber of the St. Peter in Wisconsin, but all of these were reworked from underlying units. Indigenous conodonts were described and illustrated from the St. Peter Sand- stone of Indiana by Rexroad er al. (1982). Witzke’s routine logging of a core from northwest lowa (Loc. CQ, see Appendix) in 1978 revealed the presence of rich and abundant conodont faunas during hand-lens examination of an interbedded shale unit (unit 8, Text- fig. 1) within the St. Peter succession. Subsequent pro- cessing of the shales produced large conodont collec- tions of potential biostratigraphic significance. W. M. Furnish and Gilbert Klapper generously provided ad- ditional conodont collections from a core of St. Peter Sandstone at St. Paul, Minnesota (Loc. SP) that they acquired from Bruce Olsen and Fred Sawin of the Uni- versity of Minnesota. Witzke (1980, 1992) provided some preliminary statements about the St. Peter conodont faunas from the St. Paul and Camp Quest cores, and Klapper (in green-gray |< trough crossbeds jtom. brown |7777 low-angle 54 sol agjz gf =) in a jin a ° oa) 7_— =—Z ee brown PLA EVILLE ae Te TT ae 24 LF fodk brown FORMATION 720.3 Po (ed green-gray ~~ GLENWOOD sid shale SHALE 7210 —- cee SHALE FS So 2G oc 730 0° = KEY: Pee sandstone, vf-f ° (m-c) siltstone Ce to medium gray slity = \ 739@ 1! ae & siltstone eoale ase oolitic oO ay > D644 7a1e 8 fe Oc Ironstone ° He [Z| aciomite 744@ ae 885 P phosphatic use x pyritic 5 P. ————|Pr red mottling hy da b brown shale 10 750 vertical .’, Sandy ( burrows -.- silty v1 = arglllaceous 1 to shaley 754.5@ iT ~~~ hardground or 755.5@ = ieee irregular surface cross laminae <— burrows nth subhorizontal at mediumto | 2 burrows, vertical 762 Pp dark brown eae = shale U burrows, U-shaped we tl tvartical © brachiopods 5 2{ burrows © mollusks aa @ conodont 162 133 S (all types) 2 1S 278 342 Phragmodus cf. inflexus—PA 2 2 3) 140 Pb 2 3 142 M 4 12 263 S (all types) 6 2 41 2317 Phragm. spp. (ragments) (2) (5) @) (6) (30) (153) (16) (107) (457) Plectodina sp. 2 3 > 5 226 3 9 23 Bryantodina typicalis 14 19 40 ?Bryantodina sp. 5 | | Z cf. Appalachignathus sp. 1 indet. gen. sp. C 2 Cahabagnathus sp. 4 Eoplacognathus sp. 3 Erismodus spp. (all types) 35 17 113 | | 6 10 65 55 285 17 144 97 Erismodus spp. (fragments) (7) (3) (19) (9): (@25)r 12) (61) (59) (11) Erraticodon sp. 6 1? 4 ) Erraticodon sp. (fragments) (3) Curtognathus sp. 1 1S Chirognathus duodactylus | 11 31 16 cf. Chirognathus sp. 2) cf. Leptochirognathus sp. | 1 Coleodus spp. 1 6 Archeognathus sp. | 3 9 cf. Archeognathus sp. 3 2 9 10 indet. multioistodontid? sp. 4 3? Stereoconus sp. P) l cf. Mixoconus sp. 19 I4 3 Drepanoistodus suberectus 1 14 21 8 23 3 154 2 41 S) indet. coniform spp. 2 2) 6 | Panderodus sp. 1 18 3 33 22 Oneotodus ? ovatus 2 B) 6 8 1 10 Staufferella sp. l 3 | ?Pseudooneotodus sp. 2 I misc. indet. elements I 3 | i 4 4 indet. fragments (1) (3) (4) (10) (24) (11) (48) (23) (33) (59) (4) (90) (115) scolecodonts 22 7B} 12 py) 12 inarticulate brachiopods Xe Xx X X other invertebrates x Xx Xx astraspid plates 121 is repeated baths in common household bleach (for pe- riods of months to years) slowly oxidized the organic cements resulting in progressive breakdown. The dis- aggregated shale residues were screened, dried, and manually picked. Yields were highly variable, al- though some individual samples yielded hundreds to thousands of elements. The most productive samples were some of the organic-rich brown shales which gave normalized yields commonly in excess of 1000 conodonts per kilogram. Two exceptionally productive samples from the lower St. Peter (CQ-775.7, 762.8) gave normalized yields of 66,500 and 22,400 cono- donts per kilogram, respectively (if broken elements are counted, yields to 91,000 conodonts/kg are rec- ognized). Most of Glenwood green-gray shale samples were highly productive yielding equivalents of 1100 to 5000 conodonts per kilogram. ACKNOWLEDGMENTS We are particularly grateful to Gilbert Klapper for his assistance and support during many phases of this project. His encouragement following the discovery of ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER Si7/ ‘Winnipeg Fm.\S re! WISCONSIN wis AN ce RLY DOME 24 RF e ; SN H GN _—~- e@ C O 2 PT SS i ie itinoi SY teht c, Eastern Illinois \ Sg s - =| Facies Tract Oe S S 3\ Ss > n “= ® 3 AY 9. oO 77) a | a i?) 9 t St Peter on Precambrian —-—- FS z Ne | Missouri Nebraska Kansas ‘SOUTHEAST \\NEBRAS Southern Facies Tract > OZARK DOME 0 100 200 300 km 0 100 200 mi Text-figure 2.—Study area and locality map. Hachured lines mark erosional edge of St. Peter Sandstone in the central United States and lower Winnipeg Formation in South Dakota (edge modified from Bunker er a/., 1988). Starved Rock Sandstone edge after Nunn (1986). State borders (broken lines) and major structural features are shown. Solid black circles show locations of St. Peter--Glenwood conodont samples; two-letter labels designate localities (see Appendix; all are subsurface core samples except Locality GN). Open circles show locations of additional St. Peter cores. St. Peter unconformably overlies Cambrian-Lower Ordovician strata across most of area. Area where St. Peter or Winnipeg overlies Precambrian crystalline basement denoted by diagonal ruling. St. Peter conodonts in western Iowa led to continuing Marv Carlson and Lynn Watney enabled subsurface investigation. He willingly provided St. Peter conodont core materials to be sampled at the Nebraska and Kan- collections from Minnesota that are incorporated in sas Geological Surveys, respectively. We gratefully ac- this study. His help in identifying certain taxa, espe- knowledge the helpful review comments of Stephen cially the enigmatic Archeognathus, is clearly valued. Leslie, Ray Ethington, and Jim Barrick. Numerous individuals contributed to the goals of this report, providing materials, informations assis- STIRINIG UNSER SCCIS WEIS SIE LAB GLENWOOD SUCCESSION tance, and critical discussion along the way. We ac- knowledge helpful input from Bill Furnish, Steve Schutter, Ray Anderson, Bill Bunker, Greg Ludvigson, Bob McKay, John Pope, Tony Runkel, Anita Harris, The St. Peter Sandstone was originally named for and Stig Bergstrém. The cooperation and assistance of sandstone exposures near the mouth of the St. Peter’s HISTORIC DEVELOPMENT OF STRATIGRAPHIC NOMENCLATURE 58 BULLETIN 369 River (now known as the Minnesota River) at St. Paul, Minnesota (Owen, 1847, pp. 169-170), and the type locality was designated in that area in the bluff face below Fort Snelling (Stauffer, 1934; Stauffer and Thiel, 1941). The St. Peter Sandstone has been applied as a stratigraphic label for an Ordovician sandstone- dominated formation across a vast area of the North American continental interior, and it surely constitutes one of the most geographically widespread stratigraph- ic units recognized on the continent. Across most of its extent, the St. Peter is bounded below by the Sauk- Tippecanoe cratonic unconformity (Sloss, 1963), and it is capped by various Ordovician shale, sandstone, and/or carbonate units. The St. Peter Sandstone is overlain at its type locality and across most of the study area by a relatively thin shale interval known as the Glenwood Shale. The Glenwood type locality was defined in northeast lowa (Glenwood Township, Win- neshiek County), where it 1s subdivided locally into a lower arenaceous shale and an upper non-sandy shale (Calvin, 1906, p. 75). It is a green-gray noncalcareous shale only | to 2 m in thickness across most of its extent. Templeton and Willman (1963) united the St. Peter and Glenwood formations of the Upper Mississippi Valley within the Ancell Group together with carbon- ate-dominated facies of the Dutchtown and Joachim formations to the south (southern Illinois, Missouri, Indiana). In general, the Dutchtown and Joachim for- mations have been considered lateral lithofacies equiy- alents of the St. Peter and Glenwood formations to the north. Templeton and Willman (1963) further subdi- vided the St. Peter and Glenwood into a series of members. The main body of widespread St. Peter sheet sand was termed the Tonti Member. The Starved Rock Sandstone was originally included as a member of the St. Peter (ibid.), but its lateral interfingering with and superposition above characteristic green-gray Glen- wood shales in southeastern Iowa and northern Mis- souri has prompted its inclusion within the Glenwood Formation in those areas (Nunn, 1986; Agnew, 1955, p. 1733). The Starved Rock Sandstone is an elongate east-west-trending sandstone body (Text-fig. 2) that generally serves to separate Glenwood shales to the north from the Joachim Formation to the south. LITHOFACIES OF THE ANCELL GROUP Eastern Facies Tract A general eastern facies tract (Text-fig. 2) of the St. Peter—Glenwood interval is recognized that extends from the eastern portion of the study area in central lowa and the Upper Mississippi Valley area (eastern lowa, Minnesota) eastward across Wisconsin and northern Hlinois into Michigan and northeastern Indi- ana. The St. Peter Sandstone is by exceptionally pure quartzarenite lithologies across this region. A_ re- worked coarse-grained residual unit in the basal St. Peter is commonly recognized (variously termed the Readstown or Kress Member), and thick karst- and valley-filling successions (up to 150 m thick) in the lower St. Peter locally infill a complex erosional sur- face developed on underlying strata (primarily the Lower Ordovician Prairie du Chien Group). Other than such valley-filling successions, the St. Peter displays regional thickness patterns that likely reflect variations in depositional accommodation and sediment supply. The St. Peter commonly ranges between 15 and 25 m in thickness (locally to 125 m) across eastern lowa, and it generally thickens northward into the Twin City Basin of Minnesota (45-50 m thick in the type area). Thicknesses vary across Wisconsin and northern [li- nois (commonly 25—60 m; locally to 200 m), and the St. Peter dramatically thickens eastward into the Mich- igan Basin (100-350 m). The Tonti Member is characterized by fine to me- dium-grained sandstones (minor coarse horizons) con- taining limited amounts of argillaceous material over most of this area. Sedimentary structures are often dif- ficult to resolve in the sandstones, but burrowing and cross-stratification are present, and nonmarine aeolian facies are identified in southern Wisconsin (Dott ef al., 1986). Although dominated by clean quartzarenite, ar- gillaceous sandstone and silty shale units occur within the main body of the St. Peter, and burrowed slightly argillaceous sandstones are present across much of the area. A silty shale to argillaceous siltstone unit occurs 10 to 20 m above the base of the St. Peter type area of Minnesota (Thiel, 1935; Stauffer and Thiel, 1941; Olsen, 1976), and conodonts have been recovered from this unit (Text-fig. 3, Loc. SP). Thin siltstones and shales (generally green-gray) as well as sandy do- lomite beds are present locally within the Tonti Mem- ber of Illinois (Lamar, 1928), Wisconsin (Mai and Dott, 1985), and eastern lowa. Irregular surfaces and hardgrounds, some impregnated with pyrite and apatite crusts, exist at several positions within the Tonti inter- val of eastern Iowa and Minnesota (e.g., Text-fig. 3, Locs. SS, CC; Thiel, 1935, p. 606). Eastward into the Michigan Basin the St. Peter includes complex litho- facies characterized by stacked sequences of quartzose and quartzo-feldspathic sandstone, dolomite, and thin shale with minor anhydrite (Barnes ef al., 1992: Nadon et al., 2000). A relatively thin (1-3 m) interval of green-gray Glenwood Shale overlies the St. Peter in lowa and Minnesota. This feldspathic shale includes concentra- tions of skeletal and nonskeletal apatite (Schutter, ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER 59 PLATTE- VILLE g GLEN- he WwoOoD dai zl Seceeses ST. PETER SANDSTONE v TOMS POSTS FS Sm ge y io {_ oolitic b~ phosphorite jon general position of mollusk fossils (Sardeson, 1896) PLATTE- ee VILLE FM. GLEN- Ge aes ‘JO WOOD Sa SHALE cs ; UD 2 JQ Be $ mae : | he 50 8 15 p¢W 3 a) Las LU a0 2 & 4 © 10 Des ® fo} Oo 5 2 10 Text-figure 3.—Graphic lithologic sections of St. Peter-Glenwood strata showing position of productive conodont samples used for this study (solid circles). Datum is base of Platteville Formation. See Appendix for locality information and sample depths. Symbols as in Text- figure 1. Locality SP graphic shows composite lithologic section for St. Paul-Minneapolis area adapted from Olsen (1976), Sardeson (1896), and Thiel (1935). 60 BULLETIN 369 1996), and argillaceous sandstones or siltstones may be present. Eastward into Wisconsin the Glenwood is represented by a thin interval variably displayed as a phosphatic green shale or an argillaceous bioturbated phosphatic sandstone (Fraser, 1976; Choi and Simo, 1998). The Glenwood across northern [linois forms a thicker facies complex (to 45 m), including silty ar- gillaceous sandstone, dolomite, and green-gray phos- phatic shale. The Glenwood in the Michigan Basin (to 80 m) is characterized by complex facies of sandstone, dolomite, and shale (Nadon er al., 2000). Shaley strata locally included in the upper Glenwood may be lateral facies equivalents of the lower Platteville Formation (Fraser, 1976; Sloan, 1972; Mossler, 1985). The eastern facies tract of the Glenwood Formation interfaces along its southern margin in Illinois and southeastern Iowa with the Starved Rock Sandstone (the “Re-Peter” of Agnew, 1955), an elongate body of marine sandstone. This fine- to coarse-grained, part- ly argillaceous sandstone reaches thicknesses up to 70 m, and it intercalates with sandstones and shales of the Glenwood along its northern margin (Templeton and Willman, 1963; Nunn, 1986). The Glenwood Shale in- cludes facies of brown organic-rich shale near the mar- gins of the Starved Rock complex in southern Iowa and northward into portions of central and eastern Iowa. Southern Facies Tract Although outside the study area of this report, facies relationships within the Ancell Group south of the Starved Rock Sandstone body are described here be- cause these strata have yielded biostratigraphically sig- nificant conodont faunas that are comparable to St. Pe- ter—Glenwood faunas to the north (e.g., Branson and Mehl, 1933b; Youngquist and Cullison, 1946; An- drews, 1967; Rexroad et al., 1982; Klapper and Bergs- trom, 1984: Ethington ef al., 1986). Southward across eastern Missouri (Thompson, 1991), southern Illinois (Templeton and Willman, 1963), and Indiana (Droste et al., 1982), the Ancell Group (reaching thicknesses to 210 m) becomes dominated by carbonate facies of the Dutchtown and Joachim formations. The St. Peter Sandstone occupies the basal Ancell Group in this area, but the sandstone is replaced progressively south- ward by carbonate facies of the Dutchtown Formation. The St. Peter is fine- to medium-grained quartz sand- stone with minor interbeds of argillaceous sandstone, green-gray silty shale, and dolomite (Dapples, 1955; Thompson, 1991; Droste ef al., 1982). By contrast, the Dutchtown is dominated by dark argillaceous dolomite and limestone facies, sandy in part, with interbeds of green-gray and brown organic-rich shale. The upper Ancell Group is formed by the carbonate- dominated Joachim Formation, which merges with the southern margin of the Starved Rock Sandstone body. The dolomite and limestone lithologies are variably argillaceous, silty, sandy, or stromatolitic, and inter- beds of anhydrite and green-gray and brown to black organic shales occur in some intervals (Thompson, 1991; Droste et al., 1982; Kolata and Noger, 1991). Regional lithofacies relationships north and south of the Starved Rock Sandstone suggest general strati- graphic equivalence of the Glenwood and Joachim for- mations. From its vertical and lateral stratigraphic re- lations, the Dutchtown Formation is likely a facies equivalent of some part of the St. Peter Sandstone in the northern facies tract. Western Facies Tract St. Peter and Glenwood strata across western lowa, eastern Nebraska, northwestern Missouri, and north- eastern Kansas form a distinctive but poorly known western facies tract of the Ancell Group (Text-fig. 2). This facies tract, which is restricted to the subsurface, was the primary focus of this study and the source of most of our St. Peter conodonts. It is distinguished by its higher argillaceous and phosphatic content and by occurrences of interbedded organic shale and oolitic ironstone. The western facies tract of the Ancell Group merges with the eastern facies tract across central Iowa, and lithostratigraphic equivalency is clearly ap- parent. The Ancell Group in the western facies tract is similar in thickness to that seen in eastern Lowa, gen- erally ranging between 15 and 30 m (locally thinner around the Southeast Nebraska Arch, 9-22 m; see Text-fig. 2). The western facies tract of St. Peter Sandstone is dominated by fine- to medium-grained sandstone sim- ilar to that seen in other regions, but in contrast with the eastern facies tract, it contains higher proportions of argillaceous sandstone and interbedded shale. Un- like the eastern facies, the western St. Peter includes medium to dark brown, locally black, organic-rich shale units, commonly with phosphatic clasts and py- rite cements (e.g., Locs. CQ, CT, OF). Oolitic phos- phorite, oolitic ironstone (goethite/hematite), or oolitic pyrite occur as scattered grains to discrete beds and are associated locally with organic shales. The organic shales commonly overlie pyrite- and apatite-impreg- nated sandstone hardgrounds, and coarse quartz grains are associated with some of these surfaces. Scattered burrows (including Chondrites) and silt to sand lami- nae are seen in the brown shale units. Gray and green- gray silty shale units, phosphatic to glauconitic in part, and siltstones also occur in the western St. Peter facies. The St. Peter sandstones commonly are burrowed. Horizontal burrows occur above the interbedded ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER 61 shales, but vertical (Skolithos) and U-shaped burrow forms occur in the upper parts of some sandstone units (e.g., units 5, 7, 12-13, Text-fig. 1). Planar and cross stratification is present in some sandstones. Occur- rences of oolitic ironstone are restricted to the western facies of the Ancell Group. Ironstone units (domi- nantly goethite ooids) occur at several different strati- graphic positions within the St. Peter Sandstone suc- cession, locally reaching thicknesses up to 2 to 4 m. Oolitic ironstones are present at localities in Kansas, eastern Nebraska, and western Iowa, and they are most abundant in the area of the Southeast Nebraska Arch (Leatherock, 1945; Witzke, 1980; Berendsen and Doveton, 1997). The Glenwood Shale can be recognized in the west- ern facies tract, although equivalent strata in Nebraska and northeast Kansas commonly are included within an expanded upper St. Peter Sandstone. These strata generally resemble the Glenwood Shale of the eastern facies tract and are dominated by relatively thin inter- vals of green-gray shale, phosphatic in part, or argil- laceous sandstone. However, minor brown organic-rich shale and oolitic ironstone units also occur. The western facies tract of the Ancell Group is re- placed southward into southern Kansas and Oklahoma by strata included within a portion of the Simpson Group. Informal lithostratigraphic subdivisions are ap- plied to this interval in southern Kansas, where the succession of sandstone, in part highly phosphatic to pyritic, green sandy shale, and dolomite (Doveton ef al., 1990), resembles the St. Peter-Platteville interval to the north. Although exact lithostratigraphic relation- ships are not known with certainty, most workers have correlated the St. Peter of northeast Kansas and the western facies tract with a portion of the McLish-Tulip Creek succession in Oklahoma (e.g., Dapples, 1955; Suhm, 1997; Sweet, 1992). FOSSILS OF THE ST. PETER— GLENWOOD INTERVAL Excluding bioturbation and the conodont microfau- na of the Glenwood, strata of the Ancell Group com- monly have been characterized as _ unfossiliferous across most of their extent. Nevertheless, a number of fossils have been identified within the eastern and western facies tracts during the course of this study, and previous workers have recognized fossils within St. Peter—Glenwood strata. Sardeson (1896) collected and described a mollusk-dominated marine inverte- brate fauna from the middle part of the St. Peter Sand- stone in Minnesota that includes a variety of bivalve and gastropod taxa as well as nautiloids, monoplaco- phorans, bryozoans, inarticulate brachiopods, and or- thid brachiopods (also see listing by Sloan, 1987). All carbonate shell material is dissolved, and Sardeson’s St. Peter macrofauna is preserved primarily as sand- stone molds. Bivalve molds have also been recognized in the lower St. Peter of southeastern Iowa (Loc. CC, Text-fig. 3). Residues from the St. Peter Sandstone in the western facies tract have produced, in addition to the conodonts, scattered to abundant scolecodonts and phosphatic inarticulate brachiopod shell material (see Tables 1, 2). Whole inarticulate shells have been iden- tified in some of the cores. Small phosphatized gastro- pod steinkerns, indeterminate phosphatic tubes, and ostracodes were also recovered from the St. Peter shales. Phosphatic tubercles and dermal plates from two St. Peter samples (Table 2) resemble vertebrate material known from other Ordovician localities (Elliot et al., 1991). The most abundant sample (O-1977) yielded common nodose and tuberculated plates similar to those of astraspid heterostracans (Denison, 1967). Probable heterostracan material is also Known from the Glenwood Shale of the Upper Mississippi Valley area (Schutter, 1996), and *‘fragmental plates of fossil fish” have been found in phosphatic sandstones of the Simp- son Group in Kansas (Doveton et al., 1990, p. 11). The Glenwood Shale in both the eastern and western facies tracts has yielded a poorly preserved inverte- brate fauna. Bivalve molds and phosphatic steinkerns of gastropods are known (Schutter, 1996). Inarticulate brachiopod shell material and scolecodonts are com- mon in some conodont residues. Various dolomitized, phosphatized, or pyritized skeletal grains indicate an open-marine benthic fauna in the formation, including sponge spicules, echinoderm ossicles, bryozoans, ar- ticulate brachiopods (orthids, strophomenids, rhyncho- nellids), graptolites, conularids, ostracodes, and trilo- bite fragments (Stauffer, 1935; Schutter, 1996; this study). Bivalve molds occur in the Starved Rock Sand- stone of Iowa (Loc. CC, Text-fig. 3). Invertebrate car- bonate shells are dissolved or replaced in most St. Pe- ter—Glenwood facies, suggesting that calcium carbon- ate was unstable in the respective depositional and/or diagenetic environments. DEPOSITIONAL AND PALEOECOLOGIC INTERPRETATIONS PREVIOUS STUDIES Most previous interpretions have concluded that the St. Peter Sandstone is primarily a shallow-water ma- rine shelf sand, although aeolian facies are recognized in areas of southern Wisconsin (Dott et al., 1986). Var- ious workers have stressed nearshore, littoral, shore- face, peritidal, and/or aeolian sedimentary processes and environments to explain the transportation and ac- 62 BULLETIN 369 cumulation of the mature quartz sands that typify the St. Peter. The main body of the St. Peter (Tonti Mem- ber) commonly has been interpreted as a “‘transgres- sive sheet sand” (Fraser, 1976), and Dapples (1955, p. 466) envisioned *‘an unbroken series of individual shorelines integrated along the transgressing sea [to produce] a blanket or sheet-type sandstone.” In a sim- ilar manner, some have suggested that the St. Peter is a “composite” sandstone formed by stacked succes- sions of small-scale transgressive and regressive shal- low-shelf and shoreface deposits (Thiel, 1935; Sloss, 1963; Mazzullo and Ehrlich, 1983), and that such os- cillations resulted in “spasmodic seaward dispersal of sand superimposed upon a background of continual transgression” (Dott er al., 1986, p. 365). Mazzullo and Ehrlich (1983, p. 117) recognized cyclic succes- sions marked by variations in grain shape attributed to aeolian and littoral sediment influx, and they suggested extremely slow rates of overall sediment accumulation for the St. Peter. Deposition of the Glenwood Shale has generally been attributed to renewed marine transgression marked by the accumulation of mud and sand in a variety of nearshore to offshore settings (Fraser, 1976; Choi and Simo, 1998). Peritidal carbonate facies are recognized in the Glenwood succession in its eastern extent, but the Glenwood is entirely characterized by marine facies in its western extent. Schutter (1996) interpreted the Glenwood Shale of Iowa and Minne- sota to be a condensed section reflected, in part, by high concentrations of conodonts and nonskeletal phosphate. Lateral stratigraphic equivalency of the Glenwood in that area (1-3 m thick) with the dramat- ically thicker Starved Rock Sandstone (to 70 m) to the south underscores the relative condensation of the Glenwood Shale. The Starved Rock body has been interpreted as an offshore ““marine bar complex” (Nunn, 1986) or a “lowstand shoreline complex” (Schutter, 1996, p. 62). ANCELL GROUP PALEOECOLOGIC AND DEPOSITIONAL INTERPRETATIONS FOR STUDY AREA The recognition that the St. Peter Sandstone in- cludes conodont-rich organic and phosphatic brown to black shale units, phosphorites, and ironstones in the western facies tract necessitates a re-evaluation of pre- viously proposed depositional interpretations. In par- ticular, the extremely high abundances of conodonts in some of the brown shales (up to 66,000 conodonts per kilogram) strongly suggest that these shales represent condensed marine intervals. Watney ef al. (1997, pp. 267-8) identified “laterally extensive organic-rich, py- ritic’’ shale units in the St. Peter Sandstone of north- east Kansas that they “interpreted to be condensed sections” deposited in “‘deeper, anoxic-marine, sedi- ment starved” environments. The paucity of benthic fauna and the preservation of abundant organic matter and pyrite in these con- densed shale units suggests that inhospitable dysoxic to anoxic benthic environments were present at least episodically during St. Peter deposition. Relatively high conodont diversity (>10 species) in these shale units is evidence that some portion of the water col- umn was capable of supporting a marine fauna. While it is possible that some Ordovician conodont taxa had a nektobenthic life habit (Barnes and Fahrzeus, 1975), their occurrence in dysoxic-anoxic benthic facies seems more consistent with a pelagic mode of life for most of the St. Peter conodont taxa. It is likely that a stratified water column, marked by an oxygenated sur- face layer and a dysoxic to anoxic bottom layer, char- acterized areas of the Midcontinent shelf during por- tions of St. Peter deposition (a quasi-estuarine epicon- tinental circulation system described by Witzke, 1987). Oolitic ironstones, phosphorites, and phosphatic lags in the St. Peter succession also are interpreted to mark episodes of sediment condensation or starvation. Some sedimentologists consider ironstone and phos- phorite occurrences to be products of condensed sed- imentation during periods of reduced sediment influx associated with marine transgression (e.g., Brett et al., 1998; Van Houten, 2000; Witzke and Bunker, 1996). Starved transgressive surfaces punctuate the sandstone succession, represented in places by pyrite- and apa- tite-impregnated hardgrounds. Pyrite encrustations and ooidal pyrite further indicate that dysoxic to anoxic conditions were present at least episodically during St. Peter deposition. The St. Peter—-Glenwood interval in the western fa- cies tract is characterized by a stacked succession of depositional cycles. Depending on their duration and geographic extent, such cycles may represent parase- quence- or sequence-scale depositional packages. Each cycle is marked by a condensed shale unit at its base, which commonly overlies a pyritic hardground sur- face. The most densely sampled condensed shale in- terval (Loc. CQ; Text-fig. 1, units 8-9) shows a pro- gressive upward decrease in relative condensation re- flected by declining conodont abundances (from 22,400 conodonts/kg at the base to 275 conodonts/kg at the top; see Table 1). Scattered ironstone ooids occur in some of the condensed shales (e.g., CQ 762). The condensed shale unit grades upward into a thicker sandstone interval in the upper part of each cycle. Many sandstone units display an upward increase in bioturbation and vertical burrowing, indicating as an upward-shallowing succession with increasing oxy- genation. Recurring cyclic patterns of condensed shale ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER br. > a Pecatonica Mbr. Bor oolitic Ironstone oolitic Phosporite Pp =p Carimona PP —Lr7} GLENWOOD + SHALE s a —- a J brown McGregor Mbr. -7 _v 7) Zi eS V7a =F 3 brown Se GLENWOOD 4975 chk SHALE —Pp ao > Pecatonica S r. ==1 oolitic pyrite aes =e ST. PETER SANDSTONE SY QGHG . $ Text-figure 4.—Proposed stratigraphic correlations of St. Peter through Platteville succession in four core sections, northeast Kansas to eastern Iowa (localities given in Appendix and shown on Text-fig. 2). Relationships dashed where uncertain. Platteville Formation comprises the Pecatonica and McGregor members (thinned and condensed in western Iowa). Carimona Member and Spechts Ferry Shale are included in the lower Decorah Formation: position of the widespread Deicke K-be ntonite is shown. Symbols as in Text-figure 1. Additional symbols: V (vuggy), ¢ (coarse sand), h (horizontal laminae), c/k (conodonts per kilogram), ) (echinderm debris), # (bryozoans). and sandstone deposition are displayed in the CQ core (Text-fig. 1; units 3-4, 4-6, 7, 8-10, 11-13). Similar and possibly correlative cyclic units are present throughout the western facies tract (Text-figs. 3, 4). Although information is insufficient to demonstrate unequivocal stratigraphic relationships, some of the condensed shale units in the western facies tract prob- ably correlate to pyritic hardground surfaces within the sandstone-dominated succession of eastern Iowa (hy- pothetical correlations shown on Text-fig. 4). We be- lieve such surfaces mark widespread sediment star- vation across the eastern shelf corresponding to epi- sodes of regional transgression and eustatic deepening. Similarly, the deepening-shallowing sandstone cycles 64 BULLETIN 369 recognized in the St. Peter of Minnesota (Mazzullo and Ehrlich, 1983) may correlate with shale-sandstone cy- cles of the western facies tract. Condensed brown shale units with high conodont abundances have not been recognized within the upper St. Peter interval in the western facies tract, and chang- ing patterns of regional sedimentation are proposed, marked by higher rates of sediment accumulation, overall shallower depositional conditions, and less pro- nounced cyclicity. The upper St. Peter is variably dom- inated by silty shale or massive sandstone, cross-strat- ified in part. Although less well developed than in the lower St. Peter, episodes of sediment condensation are indicated by phosphate-enriched horizons and oolitic ironstones in the upper St. Peter. A significant regional transgression is interpreted for the deposition of the overlying Glenwood Shale, which we consider to be a widespread condensed interval, characterized by high conodont abundances and phosphatic enrichment across a broad region. Organic brown shale facies are associated locally with the Glenwood interval, sug- gesting bottom dysoxia or anoxia in areas of the trans- gressing sea. Following Glenwood transgression, which onlapped siliciclastic source areas, regional de- position of subtidal carbonate facies (Platteville For- mation) ensued. Compared to eastern and southern fa- cles tracts, the Platteville Formation significantly thins to the west (Text-fig. 4) where it is interpreted to be, in part, a condensed interval. DEPOSITIONAL SUMMARY The recognition of condensed sedimentary units in the St. Peter Sandstone of the western facies tract ob- viates conventional interpretations of the formation as simply a composite product of littoral and nearshore sedimentation forming a broadly diachronous trans- gressive sheet sand. St. Peter depositional models must also accommodate organic-rich marine shale, iron- stone, and phosphatic-pyritic deposition within the succession. Sediment accumulation became highly at- tenuated at times across areas of the cratonic shelf, probably during transgressive sea-level events. Organ- ic, phosphatic, and pyritic deposition is interpreted to have occurred during such deepening episodes within a stratified dysoxic or anoxic water mass under general quasi-estuarine circulation (Witzke, 1987). The general absence of carbonate material in the Ancell Group across vast areas of the central Midcontinent suggests episodic calcite undersaturation within the stratified water mass (Witzke, 2001). High proportions of ju- venile or immature conodont elements are character- istic of some of the condensed shales. Witzke (2001) proposed that fluctuations and sporadic overturn of the pycnocline may have triggered bioevents within the seaway, resulting in high juvenile and adult mortality of the pelagic conodont faunas. The St. Peter sandstone units of the western facies tract (and likely the eastern tract as well) probably ac- cumulated as the seaway shallowed and sandy sedi- ments were transported across the shelf. Regional shal- lowing broke down seaway stratification, enabling ox- ygenated benthic environments to become widespread. Multiple transgressions and regressions of the St. Peter seaway resulted in a complex stack of depositional cy- cles in the eastern and western facies tracts, as pro- posed by previous workers. The extreme sediment condensation proposed for the organic conodont-rich shales of the western facies tract suggests that depo- sition of the St. Peter Sandstone was a geologically slow process in the cratonic sea. This interpretation echoes the earlier suggestions of Mazzullo and Ehrlich (1983, p. 117) that St. Peter sands accumulated at ex- tremely slow rates. Interpretations of the western fa- cies tract have necessitated a re-evaluation of regional models of St. Peter deposition to incorporate ideas of episodic sediment condensation and starvation. BIOSTRATIGRAPHIC INTERPRETATIONS OF THE ST. PETER CONODONTS PREVIOUS CORRELATIONS AND AGE INTERPRETATIONS OF THE ST. PETER SANDSTONE Because the St. Peter Sandstone overlies a major cratonic megasequence boundary (the Sauk-Tippeca- noe boundary of Sloss, 1963) across most of its extent and because of the general absence of biostratigraph- ically useful faunas from the sandstone lithologies, the age of the formation has been difficult to resolve. Rich conodont faunas recovered from the overlying Glen- wood Shale in the Upper Mississippi Valley area in- dicated a Mohawkian age for that unit (Stauffer, 1935, p. 131), thereby constraining the age at the top of the St. Peter Sandstone. Various authors have proposed correlations and age relationships of the St. Peter Sandstone based primarily on extrapolated regional lithostratigraphic inferences. Sardeson (1896, p. 83) was the first to propose a specific correlation: ““The Saint Peter thus remains to be correlated with the Cha- zy, [but] this correlation cannot be said to be undoubt- edly established.”” Many subsequent workers followed suit in considering the St. Peter to be primarily of Cha- zyan age (e.g., Stauffer and Thiel, 1941; Dapples, 1955; Agnew, 1955). Dapples (1955) and Suhm (1997) proposed correlation of the St. Peter Sandstone with the McLish and Tulip Creek formations of Oklahoma of presumed “late Chazy” age. However, other stratigraphers suggested that the St. Peter was primarily of Blackriveran age (e.g., Templeton and St. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER 65 Willman, 1963; Thompson, 1991). Sweet and Bergs- trém (1976) considered the St. Peter-Glenwood inter- val in the lowa-Minnesota area to be primarily of Blackriveran age (uppermost Chazyan locally at base). but the St. Peter of Missouri-Arkansas was shown to be an older unit of Chazyan age. A graphic correlation of conodont faunas from the Upper Mississippi Valley Ordovician succession pro- posed by Sweet (1984, 1987) extrapolates a line of correlation which projects the St. Peter Sandstone within the Belodina compressa and possibly the up- permost Plectodina aculeata chronozones (1.e., middle to late Blackriveran) on his constructed Composite Standard Section. Sweet (1987) considered the over- lying Glenwood Shale at St. Paul and in northeast Iowa to he within the Phragmodus undatus chrono- zone (of latest Blackriveran to earliest “Trentonian” age). Straight-line graphic extrapolations require rela- tively constant rates of sediment accumulation for the duration of the section under consideration, and the possibility of condensed sedimentation for portions of the St. Peter-—Glenwood interval could modify such correlations. However, Sweet (1987, p. 168) suggested that the Glenwood Shale *“*may have accumulated rath- er rapidly relative to those that represent the same in- terval of time in the standard reference section in Ken- tucky.” PREVIOUS CORRELATIONS OF ST. PETER CONODONT FAUNAS Clark and Miller (1971) and Grether and Clark (1980) recovered conodonts from the basal St. Peter, Readstown Member, but these are all reworked forms derived from underlying strata of the Lower Ordovi- cian Prairie du Chien Group. The first non-reworked conodonts reported from the St. Peter Sandstone were recovered in Minnesota (Loc. SP) and western Iowa (Loc. CQ), and Witzke (1980, p. 5) listed form and multielement taxa (including Phragmodus flexuosus) from these localities suggestive of a “late Chazyan” correlation. Witzke (1992) subsequently expanded the listing of St. Peter conodonts from these localities as well as localities in Nebraska and Kansas, and reported occurrences of P. flexuosus, Cahabagnathus, Eopla- cognathus, Erraticodon cf. balticus, ?Leptochirogna- thus, and other forms. He suggested similarities with upper Simpson and Dutchtown faunas and proposed a “late Chazyan—early Blackriveran” age for the cono- dont faunas of the St. Peter Sandstone. Witzke’s sug- gested correlations were disputed by subsequent work- ers. Ethington eft al. (1986, p. 10) wrote: **Witzke [1980] interpreted the St. Peter conodonts to be indic- ative of Chazyan age, although the genera he listed were not characteristic of Chazyan faunas elsewhere.” Barnes et al. (1996, p. 48) further indicated that “‘some of the faunal elements identified by Witzke (1992) ap- pear to be late Paleozoic contaminants.”” In both cases, the taxa in question were not identified. Rexroad er al. (1982) recovered elements of of sev- en species of conodonts from the St. Peter Sandstone in southwestern Indiana. They correlated this fauna with the Dutchtown Formation of Chazyan age. Shaw (1990) later recovered conodonts from the St. Peter Sandstone (basal Tonti Member) of northern Illinois (LaSalle Co.), including Coleodus sp., Lumidens vi- treus, and Scapulidens primus. The latter two species Were previously known only from the Dutchtown For- mation of Indiana (see Ethington er al., 1986), and a “late Whiterockian [Chazyan] or early Mohawkian age” was tentatively proposed for the St. Peter (Shaw, 1990). Sweet (1992) reported a succession of Ordovician conodont faunas from the subsurface of Kansas, al- though only informal lithostratigraphic labels were used to describe the stratigraphic succession. “‘Sub- surface Unit A” yielded a conodont fauna that included Phragmodus ambiguus (= P. flexuosus morphotype B), Cahabagnathus friendsvillensis, Erraticodon ct. balticus, and others. He correlated *“‘Subsurface Unit A” with the Mclish Formation of Oklahoma and in- dicated a late Whiterockian (Chazyan) age. The Kan- sas Geological Survey assigned this stratigraphic in- terval at one of Sweet’s subsurface localities (Loc. CT of this report) to the St. Peter Sandstone (see Watney et al., 1997). However, Sweet (1992, p. 187) consid- ered this interval to be considerably older than any portion of the St. Peter Sandstone of southeast Min- nesota. Additional conodont collections have been noted from the subsurface St. Peter Sandstone of the Mich- igan Basin, where the formation reaches considerably greater thicknesses than elsewhere in the Midconti- onent (up to 350 m; Barnes er al., 1992; Nadon ef al., 2000). Bergstr6m er al. (1994) identified “Archeog- nathus and Multioistodus faunas” as well as occur- rences of Leptochirognathus and Paraprioniodus from the St. Peter of the Michigan Basin: they recognized a “diversity of Mohawkian assemblages in the [over- lying] Glenwood Fm.” Barnes ef al. (1996) reported occurrences of Archeognathus spp., Multioistodus spp.. Coleodus spp., and Erismodus spp. from the up- per St. Peter in Michigan, and they noted Phragmodus flexuosus (morphotype A) from the Glenwood. They indicated a “‘medial to late Whiterockian age” for the Michigan St. Peter which they regarded as “older than the bulk of the St. Peter of the Upper Mississippi Val- ley”’ where the formation “‘appears to be, in part, Mo- hawkian in age” (Barnes ef al., 1996, p. 49). 66 BULLETIN 369 BIOSTRATIGRAPHIC RELATIONS OF ST. PETER— GLENWOOD CONODONT FAUNAS The collections of conodonts from the St. Peter and Glenwood recovered for this study include forms of potential biostratigraphic significance. The abundance of Phragmodus flexuosus trom the lower and middle St. Peter in the CQ core is important, as this species was considered to be restricted to the Chazyan (upper Whiterockian) by Klapper and others (1981, p. 256) and Sweet and Bergstrom (1976). The North American Composite Standard Section later constructed by Sweet (1984) extended the range upward from the Chazyan into the basal Mohawkian (lower Blackriv- eran), overlapping with the lower range of P. inflexus in its upper part (see also Leslie and Bergstrém, 1995; Bauer, 1994). Occurrences of P. cf. ambiguus in the St. Peter of Nebraska and Kansas is consistent with a similar age range, as P. ambiguus is known only from Chazyan and basal Blackriveran strata (Bauer, 1994; highest occurrences overlap slightly with the lowest Eoplacognathus elongatus in the lower Bromide Fm.). Occurrences of Cahabagnathus in the St. Peter of Iowa and Kansas are of particular importance, even though the small to fragmentary aspect of our speci- mens does not permit a clear species-level classifica- tion. Cahabagnathus is primarily a Chazyan genus (Sweet, 1984), but a late form (C. carnesi) apparently extends into the lowermost Blackriveran (Bergstr6m and Carnes, 1976; Bergstr6m, 1983). The presence of a continuous denticle row on the stelliplanate element joining anterior and posterior processes on the St. Peter specimens precludes assignment of these forms to late species of Cahabagnathus that show a denticle gap between the processes (i.e., C. sweeti, C. carnesi). This indicates a pre-C. sweeti Zone age and supports cor- relation within some portion of the C. friendsvillensis Zone (see zonal subdivisions of Sweet, 1984). The St. Peter specimens most closely resemble C. directus (from the McLish) and C. friendsvillensis. Sweet (1992) previously reported C. friendsvillensis from the same Kansas core (Loc. CT) used in this report. The occurrences of Cahabagnathus in the lower St. Peter obviate a Blackriveran age and are most consistent with an early to middle Chazyan (C. friendsvillensis Zone) correlation (or a late Llanvirnian age in the Brit- ish Series; see Bergstr6m, 1983; Webby, 1998). Frag- mentary elements of Eoplacognathus from the St. Pe- ter of lowa and Kansas are not identifiable at the spe- cies level, but the preserved material is similar to E. foliaceus and E. reclinatus (see Systematic discus- sion). If this evaluation is correct, these forms likely pre-date E. elongatus and would support a Chazyan correlation. Leptochirognathus is restricted to the upper White- rockian (Sweet, 1984), supporting a Chazyan age for the shale interval within the St. Peter Sandstone at St. Paul, Minnesota (Loc. SP). Erraticodon sp. 1s a locally common conodont in the St. Peter, and the genus is not known to occur above the Whiterockian. However, the species represented in the St. Peter is more derived than other described Erraticodon species (reduction or loss of lateral or posterior processes), and any bio- stratigraphic significance remains to be demonstrated. Occurrences of diverse assemblages of other hyaline conodont taxa in the St. Peter collections are generally consistent with a Chazyan and/or Blackriveran age, but the biostratigraphic ranges of many of these taxa re- main uncertain. The lower St. Peter has yielded an Erismodus species resembling E. arbucklensis (a spe- cies not known to range above the Chazyan; Bauer, 1987, 1994). Indeterminate Genus and species B from the St. Peter of Iowa may represent a late surviving form within the serrate Histiodella clade, possibly sup- porting a Whiterockian age. However, the phylogenet- ic identity of this taxon remains unclear, and any bio- stratigraphic inferences are tentative. Although serrate Histiodella are most characteristic of mid-Whiterock- ian associations (Sweet, 1984), serrate forms are noted to locally overlap with the range of P. flexuosus (Har- ris et al., 1979; Moskalenko, 1973). An upward range extension of such forms into the Chazyan is postulated consistent with the composited range of serrate His- tiodella (H. serrata) reported by Sweet (1995). The preponderance of biostratigraphic evidence in- dicates a Chazyan age for the lower to middle St. Peter succession even in the paleogeographically most shoreward areas of St. Peter deposition bordering the Transcontinental Arch (e.g., Locs. CQ, SP). Broad- scale regional diachroneity of the lower St. Peter can- not be demonstrated with the available biostratigraphic control. In general, the lower St. Peter faunas share similarities with associations reported from the Dutch- town Formation of Missouri (Klapper and Bergstr6m, 1984, p. 954; Youngquist and Cullison, 1946) and McLish Formation of Oklahoma (Bauer, 1987). How- ever, the upper part of the St. Peter Sandstone has pro- duced sparse conodont collections of limited biostrati- graphic significance, and the correlation of this inter- val remains uncertain. The stratigraphic position of these strata above Chazyan faunas and below the Glen- wood Shale (interpreted to be of Blackriveran age) suggests a late Chazyan or early Blackriveran age for the upper St. Peter. The conodont faunas of the overlying Glenwood Shale were initially interpreted by Stauffer (1935, p. 131) to be of Mohawkian age. Sweet (1984, 1987) constructed a graphic correlation that incorporated St. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER 67 Glenwood Shale conodont collections from southeast Minnesota (data of Webers, 1966) and northeast lowa. The positions of the Glenwood faunas were plotted against his Composite Standard Section (CSS) result- ing in a graphic correlation of the Glenwood Shale with a relatively short interval on the CSS. Sweet’s (1984, 1987) correlations proposed that the Glenwood Shale in the Upper Mississippi Valley is primarily of post-Blackriveran age corresponding to the lower part of the Phragmodus undatus Zone (and locally into the highest part of the Belodina compressa Zone). The overlying Platteville Formation was included as a post- Blackriveran unit within the P. undatus Zone. Sweet (1987, p. 168) discussed plotting anomalies for north- east lowa between the K-bentonites (higher in the suc- cession) and the “line of correlation” defined by the first- and last-occurrence positions of certain conodont taxa. If the Glenwood is a condensed section as pro- posed by Schutter (1996), a straight-line graphic ex- trapolation through the St. Peter-Glenwood may sig- nificantly underestimate the duration of that interval. The presence of the Deicke K-bentonite higher in the succession firmly constrains an upper age limit of the St. Peter and Glenwood faunas of lowa and Minnesota (Kolata et al., 1986). The well-known invertebrate faunas of the overlying Platteville Formation (sub-Carimona Member) in the Upper Mississippi Valley have been interpreted con- sistently to be of Blackriveran age (e.g., Cooper, 1956; Kolata, 1975; DeMott er al., 1987). If these correla- tions are correct, the underlying Glenwood Shale must also be no younger than Blackriveran. However, a Blackriveran age for the Glenwood-Platteville interval is at odds with the correlations of Sweet (1984, 1987). It is unclear if the modified base of the Mohawkian noted for Sweet’s (1995) CSS changes the earlier Glenwood-Platteville correlations, as the composite ranges for some Glenwood-Platteville taxa (Polypla- cognathus ramosus, Phragmodus inflexus) have been modified from that given in earlier versions. The rang- es of certain Glenwood-Platteville taxa given for Sweet’s (1984, 1987) CSS indicate first appearances at or above the highest Blackriveran (including Phrag- modus cognitus, Polyplacognathus ramosus, Scy- phiodus primus, Chirognathus duodactylus, Bryanto- dina typicalis). However, some of these taxa are known to co-occur with Blackriveran and Chazyan faunas elsewhere, and significant range modifications are suggested. Scyphiodus and P. ramosus co-occur with Appalachignathus delicatulus and other Blackriv- eran taxa in the Mackenzie Mountains (Tipnis ef al., 1979, p. 58), Scyphiodus primus co-occurs with Phragmodus flexuosus and Cahabagnathus friendsvil- lensis in Chazyan strata of Kansas (Sweet, 1982, p. 1045), and Chirognathus duodactylus co-occurs with Cahabagnathus sweeti in Oklahoma (Bauer, 1994). We recommend that the Glenwood and Platteville cono- dont faunas of the Upper Mississippi Valley be re- correlated to accommodate Blackriveran ranges in the Ordovician CSS. Further study is needed to resolve the apparent discrepencies between the Blackriveran age indicated by the Platteville invertebrate fauna and the Glenwood-Platteville correlations of Sweet (1984, 1987). Our present interpretation is that the Glenwood Shale in lowa, Minnesota, and Nebraska is a relatively condensed unit of Blackriveran age. Polyplacognathus ramosus and Belodina compressa were identified from the Glenwood Shale by Stauffer (1935), Webers (1966), and Sweet (1987). These species were not rec- ognized in any of the Glenwood collections used for this study nor in the Washington Avenue (Minneapo- lis) Glenwood collections of Webers (1966) and Stauf- fer (1935), but they are common in overlying Platte- ville strata. Strata included in the upper Glenwood Shale in parts of Minnesota are considered to be lateral lithofacies equivalents of lower Platteville strata else- where (Sloan, 1972; Mossler, 1985). Therefore, it is likely that some of the Minnesota Glenwood conodont collections may include samples that post-date the Glenwood Shale succession in sections across most of Iowa and the Twin Cities area of Minnesota. Further study of the lithostratigraphic relations of Glenwood strata in Minnesota is needed, but two separate litho- stratigraphic units may be inadvertently lumped to- gether under this label (7.e., a lower “*true Glenwood” and an upper shale unit correlative with the lower Platteville). SYSTEMATIC PALEONTOLOGY INTRODUCTION A full systematic paleontologic treatment of the St. Peter—Glenwood conodont faunas is not presented in this report for several reasons. First, the conodont col- lections are dominated by a few well-known taxa whose classification, diagnoses, descriptions, synony- mies, and occurrences are well established in the lit- erature (e.g., Phragmodus flexuosus, P. cognitus, Dre- panoistodus erectus). Second, many of the rarer taxa are represented in the collections by fragmentary or problematic materials that are not well suited for for- mal systematic treatment. Additional specimens and further study are deemed necessary to resolve the spe- cies-level (and in some cases genus-level) taxonomic placement of these taxa. Finally, certain taxa, some abundantly represented in the collections, display a broad range of morphologic variation that has proven 68 BULLETIN 369 difficult to constrain in a clear systematic manner with- out additional study. Further study may clarify the spe- cies-level taxonomy of forms left in indeterminate sta- tus (open nomenclature) for this report, especially el- ements assigned to the genera Erismodus, Erraticodon, and Curtognathus. All conodont collections are permanently reposited in the Paleontology Repository, Department of Geo- science, University of lowa (lowa City, Iowa). Illus- trated specimens and selected reference materials are assigned catalog numbers (SUI prefix). Terminology and element locational notation largely follow Sweet (1981, 1988). Order PROTOPANDERODONTIDA Sweet, 1988 Family PROTOPANDERODONTIDAE Lindstr6m, 1970 Genus ONEOTODUS Lindstrém, 1955 Oneotodus? ovatus (Stauffer, 1935) Plate 4, figure 5 Discussion.—Distictive small coniform elements with albid cusps and an expanded flat sub-circular hy- aline base are assigned to Oneotodus? ovatus. This species is scattered in samples from the St. Peter Sand- stone (Locs. CQ, SP, OF CT) and Glenwood Shale (Locs. CQ, GN, DL, SS; see also Stauffer, 1935; We- bers, 1966). Bauer (1987, p. 23) questioned the generic assignment of this species, as the flat base does not conform with the diagnosis of Oneotodus given by Ethington and Brand (1981). Genus PSEUDOONEOTODUS Drygant, 1974 Pseudooneotodus species Discussion.—A few specimens from the Glenwood Shale of Iowa (GN, J-1021) are squat conical forms with a pointed apical denticle (centrally to posteriorly located), thin walls, an oval basal outline, and a broad- ly excavated base. These specimens (SUI 99484, 99485) are assigned to an indeterminate species of Pseudooneotodus (similar to P. cf. beckmanni of Les- lie, 2000). Squat conical elements from other Ordo- Vician units include Lepodus minutus Branson and Mehl, 1933a, L. sp. Webers, 1966, and Ambalodus mi- tratus Moskalenko, 1973 (= P. mitratus, see Leslie, 2000), but these forms all differ from the Iowa spec- imens in possessing lobate to triangular basal outlines. Genus STAUFFERELLA Sweet, Thompson, and Satterfield, 1975 Staufferella cf. S. faleata (Stauffer, 1935) Plate 4, figure 10 Discussion.—A few fragmentary symmetrical (Sa) elements from the Glenwood Shale of Iowa are as- signed to Staufferella sp. cf. S. falcata (type S. falcata from the Glenwood Shale of Minnesota, Stauffer, 1935). Symmetrical specimens from the St. Peter Sandstone (C-3387, CQ-776.7) possess lateral costae that are slightly narrower and not basally alate as in S. falcata. It is unclear if a posterior groove or keel is present, as the posterior faces are broken on these specimens. An unassigned species of Staufferella from the McLish and Tulip Creek formations of Oklahoma (Bauer, 1987) is more narrowly tapered at the tip. Family DREPANOISTODONTIDAE Fahraeus and Nowlan, 1978 Genus DREPANOISTODUS Lindstr6m, 1971 Drepanoistodus suberectus (Branson and Mehl, 1933b) Plate 4, figures 1, 2, 6, 7 Discussion.—Coniform elements assigned to Dre- panoistodus suberectus are scattered to common in samples from the St. Peter and Glenwood formations in the study area. The skeletal apparatus of this well- known and widespread Ordovician species includes several types of coniform elements (Bergstr6m and Sweet, 1966; Sweet, 1988; Bauer, 1987), and the St. Peter—Glenwood specimens are largely indistinguish- able from previously published descriptions of the spe- cies. However, a few specimens of geniculate coniform elements (e.g., Pl. 4, fig. 2) from the lowermost sample in the CQ core (CQ-776.7) display a smaller cusp an- gle than generally seen for D. suberectus, and these bear some resemblance to D. angulensis (see descrip- tion by Bauer, 1987, p. 16). Indeterminate ?drepanoistodontid species Discussion.—A collection of small hyaline non-ge- niculate coniform elements with recurved cusps from the lower St. Peter Sandstone (CQ-775.7) resemble Drepanoistodus in general mophology. However, these forms possess deep flaring subcircular basal cavities of notably larger proportions than seen in typical Dre- panoistodus. In addition, the basal cavity extends up- ward from one-third to over one-half the length of the cusp. These forms likely represent a previously un- described taxon, possibly a drepanoistodontid. Order PANDERODONTIDA Sweet, 1988 Family PANDERODONTIDAE Lindstrém, 1970 Genus PANDERODUS Ethington, 1959 Panderodus species Plate 4, figure 4 Discussion.—Recurved coniform elements bearing a longitudinal furrow from the Glenwood Shale of ST. PETER—GLENWOOD CONODONTS: WITZKE AND METZGER 69 eastern Iowa (Loc. GN) and equivalent strata in eastern Nebraska (Loc. SM) are identified as Panderodus sp. Order PRIONIODONTIDA Dzik, 1976 Family OISTODONTIDAE? Lindstr6m, 1970 Genus OISTODUS Pander, 1856 Oistodus? venustus Stauffer, 1935 Discussion.—Rare squat geniculate coniform ele- ments from the Glenwood Shale in the CQ core (SUI 99486) are identical to the form species Oistodus ven- ustus described from the Glenwood Shale of Minne- sota by Stauffer (1935) and Webers (1966). The ge- neric assignment is queried following Bauer (1994, p. 363). This form species may be associated with the apparatus of one or more species of Dapsilodus (ibid.) or some other taxon (Bergstr6m and Sweet, 1966), but no Dapsilodus or other species association has been recognized in the Iowa samples. Indeterminate Genus and species B Plate 1, figure 2; Text-figure 5 Discussion.—A single broken denticulated blade from the lower St. Peter Sandstone of western Iowa (CQ-762) does not resemble any other conodont re- covered from the formation. The specimen is albid (hyaline base) and bears eight subequal erect to slight- ly reclined denticles that are fused for half or more of their length. The blade is thin and possesses a narrow basal trough that runs the length of the specimen. The denticles and upper part of the blade are marked by numerous fine microstriations (Text-fig. 5). The overall morphologic details of this specimen most closely re- semble those described for some species included in the genus Histiodella (see McHargue, 1982), including the thin blade-shaped form, the narrow basal trough, and the finely striated aspect of the upper margins. Although differences are noted in the denticulation and basal margin, the St. Peter specimen shares many mor- phologic features in common with the anterior process of the “bladelike element” of H. holodentata Ething- ton and Clark, 1981, and the late-stage “‘denticulate morphotype” of Histiodella (McHargue, 1982). The broken aspect of the single St. Peter specimen and the relatively late stratigraphic occurrence of this form make assignment to Histiodella ill advised at present, and it is left in indeterminate status for this report. For the most part, Histiodella is not known to co-occur with Phragmodus flexuosus 1n most stratigraphic sec- tions. However, serrate Histiodella are noted by Harris et al. (1979, p. 13, figs. 4, 17) to overlap with the range of P. flexuosus in the upper Antelope Valley Limestone in the Monitor Range of Nevada. Moskalenko (1973) also reported the co-occurrence of P. flexuosus and an undescribed species of Histiodella in Siberia. A single specimen of a serrate Histiodella (H. n. sp. 2, Harris et al., 1979) was noted from the lower McLish For- mation of Oklahoma, although Bauer (1987, p. 9) con- sidered the conodonts from that interval to be re- worked. Sweet (1995) revised the composited range of Histiodella to extend well into the Chazyan (overlap- ping with the ranges of P. flexwosus and Cahabagna- thus friendsvillensis). It is proposed that the St. Peter specimen may represent a late surviving member with- in the serrate Histiodella clade. Family BALOGNATHIDAE? Hass, 1959 Indeterminate balognathid? species Discussion.—A small indeterminate pastinate ele- ment from the Glenwood Shale (CQ-721) displays a Y-shaped finely denticulated upper margin All pro- cesses are thin (same width as the denticles). The slightly curved lateral process is subequal in length to the anterior process. The central cusp is small, roughly equal in size to the adjoining denticles. This element does not resemble any described Ordovician taxon, but its pastinate morphology may suggest inclusion within the Balognathidae or Polyplacognathidae. Family POLYPLACOGNATHIDAE Bergstrom, 1981 Genus CAHABAGNATHUS Bergstrém, 1983 Cahabagnathus species Plate 2, figures 1, 2, 7 Discussion.—Small collections of partial to frag- mentary elements from the lower St. Peter Sandstone of western Iowa (CQ-776.7, 775.7, 762) and north- eastern Kansas (C-3387) include distinctive forms as- signed to Cahabagnathus, although the species assign- ment is unclear. The most complete Iowa specimen is a small, presumably juvenile, pastiniplanate element with the anterior process missing (PI. 2, fig. 1); the broad rounded posterior process resembles that seen in C. directus Bauer, 1987 (a species named from the McLish Formation of Oklahoma). It also bears some resemblance to C. n. sp. B of Leslie and Lehnert (1999) from the Joachim Dolomite of Arkansas. Ad- ditional Iowa specimens include broken stelliplanate elements with straight rows of denticles; these speci- mens most closely resemble C. directus and C. friends- villensis (Bergstrom, 1971). Specimens from Kansas include fragmentary stelli- planate and pastiniplanate elements displaying ridges and nodes (PI. 2, figs. 2, 7). The posterior process of the pastiniplanate elements is broadly rounded; the denticle row is not in a straight line; a continuous den- ticle row joins anterior and posterior processes (no gap BULLETIN 369 ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER Wl Text-figure 5.—Indeterminate Genus and species B; SEM photomicrograph of denticles showing microstriations (SUI 95016). *350 (310 pm field of view). PLATE 1 All figures (photographs) 40. Specimens lightly coated with ammonium chloride sublimate. 1, 5. Indeterminate Genus and species A 1. Pastinate P element; SUI 95014, CQ-776.7. 5. Stellate P element; SUI 95015, CQ-776.7. Indeterminate Genus and species B 2. fragmentary blade-like element; SUI 95016, CQ-762. 3, 4. Plectodina sp. 3. Sb element; SUI 95017, SM (S-1158). 4. Sb element; SUI 95018, SM (S-1159). 6-17. Phragmodus flexuosus Moskalenko, 1973 6. Sb element; SUI 95019, CQ-762. 7. Sa element; SUI 95020, CQ-762. 8. Sa element; SUI 95021, CQ-762. 9. Sc element; SUI 95022, CQ-762. 10. Sc element; SUI 95023, CQ-762. 11. Pb element; SUI 95024, CQ-762. 12. Pb element; SUI 95025, CQ-762. 13. Pb element; cusp; SUI 95026, CQ-62 14. M element; cusp; SUI 95027, OF (O-1977). 15. M element; SUI 95028, CQ-762. 16. Pa element; SUI 95029, CQ-762. 17. Pa element; SUI 95030, CQ-762. 18-23. Phragmodus cognitus Stauffer, 1935 18. Sa element; SUI 95031, CQ-720.3. 19. Pb fragment; SUI 95032, CQ-720.3. 20. Pa, aberrant specimen with incipient dichognathiform process; SUI 95033, CQ-720.3. 21. Pb element; SUI 95034, CQ-720.3. 22. Sb element; SUI 95035, CQ-720.3. 23. Sc element; SUI 95036, CQ-720.3. N y Wey aanitily oh iD ew ] Mle call ti N ~ ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER WT} as in C. sweeti). These specimens most closely resem- ble C. directus and C. friendsvillensis. Sweet (1992) reported the occurrence of C. friendsvillensis from the same Kansas core (Loc. CT) in a stratigraphic interval he termed “Subsurface Unit A”; this interval is as- signed to the St. Peter Sandstone following the strati- graphic classification of this core section by the Kan- sas Geological Survey (Watney ef al., 1997). Genus EOPLACAGNATHUS Hamar, 1966 Eoplacognathus species Plate 2, figure 3 Discussion.—Rare elements from the lower St. Pe- ter Sandstone of western Iowa (CQ-776.7, 775.7) and northeastern Kansas (C-3386) are assigned to Eopla- cognathus, although species assignment is precluded by the fragmentary nature of the specimens. Most specimens are broken anterior processes that are slight- ly curved and distally-pointed; the pointed and curved aspect of these specimens is most similar to that of E. foliaceus (see Bergstrom, 1971) and E. sp. (of Bauer, 1987). Some of these are not readily distinguishable from the anterolateral process of stelliplante elements of Cahabagnathus (see illustrated specimen). Howev- er, additional Iowa specimens (CQ-775.7) preserve the central region of the pastiniplanate elements and show an enlarged denticle (or cusp) at the junction of the three processes; this character has been observed only in E. reclinatus (see Bergstr6m, 1971), a European species. Elements informally classified as “E. foli- aceus—E. reclinatus transition” from Nevada (Harris et al., 1979) and the morphologically similar FE. sp. from the McLish Formation (Bauer, 1987) differ from the St. Peter specimens in possessing a sinuous row of denticles on the anterior process of the pastiniplanate elements. Although differing from these Nevada and Oklahoma specimens, the lower St. Peter occurrences may also show transitional aspects between E. foli- PLATE 2 All figures (photographs) *40. Specimens lightly coated with ammonium chloride sublimate. 1, 2, 7. Cahabagnathus sp. 1. juvenile pastiniplanate element; SUI 95037, CQ-776.7. 2. fragmentary pastiniplanate element; SUI 95038, CT (C-3387). 7. broken process of stelliplanate element; SUI 95039, CT (C-3387). 3. Eoplacognathus sp. 3. broken process; SUI 95040, CT (C-3386). 4, 5. Chirognathus duodactylus Branson and Mehl, 1933a 4. Sa element (“C. multidens” ); SUI 95041, CQ-721. 5. Sb? element; SUI 95042, CQ-721. 6, 11. cf. Chirognathus sp. 6. indeterminate element; SUI 95043, CT (C-3386). 11. indeterminate element; SUI 95044, CT (C-3386). 8. 9. Indeterminate Genus and species C 8. Pa element; SUI 95045, O-1977. 9. elongate broken process; SUI 95046, O-1977. 10. cf. Leptochirognathus sp. 10. fragmentary element with compressed denticles; SUI 95047, SP-L (12-13.5). 12. cf. Coleodus sp. 12. indeterminate bar-like element; SUI 95048, CQ-776.7. 13, 14, 16, 17. Coleodus sp. 13. broken blade; SUI 95049, CQ-776.7. 14. complete element; SUI 95050, CQ-762. 16. nearly complete element; SUI 95051, OF (O-1977). 17. nearly complete element; SUI 95052, OF (O-1977). 15. Erraticodon sp. 15. broken process with reclined denticles (for comparison with Coleodus and Archeognathus); SUI 95053, CQ-762. 18, 21, 23. Archeognathus sp. 18. isolated denticle; SUI 95054, CQ-762. 21. conjoined denticles; SUI 95055, SP-U (25.5—27). 23. isolated denticle; SUI 95056, CQ-762. 19, 20, 22. cf. Archeognathus sp. 19. conjoined denticles, basal groove displayed; SUI 95057, CQ-762. 20. conjoined denticles; SUI 95058, CT (C-3387). 22. partial crown; SUI 95059, CQ-762. 74 BULLETIN 369 aceus and E. reclinatus in possessing an enlarged den- ticle (like E. reclinatus) but with a slightly curved an- terior process (like E. foliaceus). Fragmentary pasti- niplanate elements from higher in the St. Peter (CQ- 762.8, 757) are tentatively included with E. sp. Family MULTIOISTODONTIDAE Harris, 1964 Genus LEPTOCHIROGNATHUS Branson and Mehl, 1943 cf. Leptochirognathus species Plate 2, figure 10 Discussion.—Two fragmentary specimens from the lower St. Peter shale unit at St. Paul, Minnesota (Loc. SP), are tentatively identified as an indeterminate spe- cies of cf. Leptochirognathus. The illustrated specimen is hyaline and preserves two large laterally compressed denticles with relatively sharp upper margins, features characteristic of the genus. The denticles are relatively short with rounded margins, and a_ shallow basal trough extends the length of the specimen. The spec- imen bears some resemblance to the graciliform ele- ment of L. guadratus (“L. gracilis”) described by Branson and Mehl (1943, p. 377), which includes a “short, stout, somewhat rounded”’ first denticle, and a long trough-like basal cavity. However, most described elements of Leptochirognathus are characterized by compressed elongate pointed denticles, aspects not seen on the St. Peter specimen (although rounded to blunted denticles are illustrated for an element of L. n. sp. from Nevada by Harris er al., 1979, pl. 1, fig. 18, and described for the anterior denticle of the quadra- tiform element of L?. sp. | from the Tyner Fm., Oklahoma, Bauer, 1989). The second St. Peter speci- men preserves one relatively stout compressed pointed denticle, but its fragmentary nature makes inclusion here tenuous. Indeterminate multioistodontid? species Discussion.—Four indeterminate hyaline elements from the lower St. Peter of Nebraska (O-1977) are included here. Two bipennate elements with a long recurved cusp (posterior process 4 denticles, shortened anterior process | to 2 denticles) resemble the “‘cyr- toniodiform” elements of Paraprioniodus costatus il- lustrated by Rexroad et al. (1982, fig. 7) from the Ev- erton Dolomite. Two pastinate “‘prioniodiform”’ ele- ments display shorter cusps flanked by posterior and anterior processes with one to two denticles, a short lateral process with a single denticle, and a broad basal cavity. Gross morphologic similarities with Paraprion- iodus Suggest tentative relationships with the Multiois- todontidae. A few fragmentary elements from the low- er St. Peter of Kansas (C-3387) have compressed cos- tate cusps similar to some multioistodontid taxa (e.g., Neomuttioistodus). Family PLECTODINIDAE Sweet, 1988 Genus PLECTODINA Stauffer, 1935 Plectodina species Plate 1, figures 3, 4 Discussion.—Various specimens from the St. Peter Sandstone and Glenwood Shale of Iowa and Nebraska are assigned to Plectodina, but, for the most part, these small and generally fragmentary elements are not eas- ily identified to species level. These elements are left in Open nomenclature, although morphologic differ- ences in the length and denticulation of the posterior process of the Sc elements between the St. Peter sam- ples and Glenwood samples suggest that more than One species is probably represented. It is possible that some small Pa and Pb elements of Plectodina have been inadvertently included with Phragmodus in Ta- bles 1 and 2, but the distinctive S elements of Plec- todina are more easily distinguished, especially the di- gyrate Sb elements. Plectodina is a rare taxon through- out the St. Peter Sandstone, but it is locally common in the some Glenwood Shale samples (e.g., Loc. GN). Most, if not all, specimens of Plectodina from the Glenwood Shale are probably assignable to Plectodina aculeata (Stauffer, 1930). M elements from one St. Peter sample (CQ-775.7) resemble Plectodina sp. il- lustrated by Bauer (1987) from the McLish Formation of Oklahoma. Family CYRTONIODONTIDAE Hass, 1959 Genus BRYANTODINA Stauffer, 1935 Bryantodina typicalis Stauffer, 1935 Discussion.—Distinctive thin blade-like multidenti- culate pectiniform and ramiform elements of Bryan- todina typicalis occur in some Glenwood Shale sam- ples (GN, CQ720.3, J-1021, SS-753). This well-known species was first described from the Glenwood Shale of Minnesota (Stauffer, 1935; see also Webers, 1966). ?Bryantodina species Discussion.—A few fragmentary thin blade-like multidenticulate carminate pectiniform and ramiform elements were recovered from two St. Peter samples (CQ-757, O-1977). The denticulation and thin blade- like aspect of these specimens bear resemblance to Bryantodina typicalis from the Glenwood Shale. How- ever, their fragmentary nature precludes clear taxo- nomic assignment, and they are provisionally labeled as? Bryantodina sp. The best preserved Pa element (SUI 99487) has 9 erect partially fused denticles on the posterior process and 3 denticles on the anterior ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER TS) process. Ramiform fragments also show erect partially fused small denticles. Bryantodiniform elements re- covered from Glenwood Shale equivalents in eastern Nebraska (S-1158, 1161, 1162) are fragmentary, and these specimens are tentatively labeled as ?Bryanto- dina sp., although they likely represent fragments of B. typicalis. Specimens provisionally labeled as “Bryantodina” sp. were reported from the McLish Formation of Oklahoma by Bauer (1987). Genus PHRAGMODUS Branson and Mehl, 1933b Phragmodus flexuosus Moskalenko, 1973 Plate 1, figures 6-17 Discussion.—Elements of Phragmodus flexuosus are the dominant conodonts of the lower to middle St. Peter Sandstone in western Iowa (Loc. CQ, see Table 1). Mature conodont elements in the St. Peter collec- tions agree in most salient details with the descriptions given for the apparatus of P. flexuosus in Klapper et al. (1981) and Bauer (1987; P. flexuosus morphotype A). Moskalenko (1972, 1973) apparently included ad- ditional elements within her apparatus reconstruction that are not recognized in the St. Peter collections. P elements are differentiated (Pa, Pb) in the St. Peter collections, thereby precluding assignment to P. am- biguus Bauer, 1994. Mature Pa and Pb elements are dichognathiform in all samples. However, immature Pa elements (one-fifth to one-half the length of the largest specimens) are variably dichognathiform to ozarkodi- niform in a few samples. Small immature elements of Phragmodus are abundant in samples CQ-775.7 and CQ-762.8, and, although the mature Pa elements of P. flexuosus are indistinguishable in the two samples, the immature specimens differ between the two samples. The lower sample (CQ-775.7) contains small Pa ele- ments dominated by dichognathiform morphologies, but a few specimens lack the dichognathiform process (i.e., are ozarkodiniform). By contrast, all small im- mature Pa elements in the higher sample (CQ-762.8) are ozarkodiniform with no trace of a dichognathiform process or “wrinkle.” In this respect, these small im- mature Pa elements are largely indistinguishable from those of the Midcontinent endemic species P. cognitus Stauffer, 1935. However, because no larger mature specimens of P. cognitus are recognized in the St. Pe- ter samples, and because the small ozarkodiniform Pa elements grade into the larger dichognathiform Pa el- ements of P. flexwosus (sample CQ-775.7), it seems likely that the small ozarkodiniform Pa elements rep- resent a juvenile ontogenetic stage present within some populations of P. flexuosus. This interpretation may explain the subsequent phylogenetic origin of P. cog- nitus via paedomorphosis from certain Midcontinent North American stocks of P. flexuosus. M elements of P. flexuosus within the St. Peter sam- ples are generally dolabrate, unlike the exclusively ge- niculate coniform (oistodontiform) M elements of P. polystrophos Watson, 1988 (= P. harrisi of Bauer, 1989). Most St. Peter specimens display four denticles on the posterior process, but some specimens, both mature and immature, variably display from one to five denticles. Immature small M elements are com- mon in samples CQ-775.7 and CQ-762.8, and inter- esting variations are noted. The lower sample (CQ- 775.7) includes common geniculate coniform elements (adentidulate posterior process), but some specimens show one to three denticles on the posterior process. By contrast, the upper sample (CQ-762.8) contains im- mature small M elements dominated by dolabrate mor- phologies with three to four denticles on the posterior process, but some show reduced denticles (1 to 2) and a few appear to be geniculate coniform. Variation of M-element morphology was discussed by Bauer (1989, p. 103), and he proposed that the apparatus of P. flexuosus likely “possessed both types of M ele- ments” (dolabrate and coniform). Likewise, Moska- lenko (1972, 1973) included both dolabrate and genic- ulate coniform elements within her apparatus recon- struction of P. flexuosus. Sc elements in all samples are cordylodontiform and display a relatively straight posterior process with faintly sinuous denticles. Mature Sa and Sb elements are similar in general morphology (phragmodontiform) and are distinguished from the Sc elements by the presence of small lateral processes (seen as narrow ridges or costae) marginal to the cusp and a broadly arched and sinuous posterior process. Unlike the Sc elements, which bear relatively uniformly sized small denticles on the posterior process, the posterior pro- cesses of the Sa and Sb elements display one or more (generally two or three) large denticles similar in size to the cusp. Large numbers of immature Sa and Sb elements (one-fifth to one-half the size of the larger specimens) are contained in samples CQ-775.7 and CQ-762.8, and significant variations are seen between these samples. The lower sample (CQ-775.7) contains small Sa and Sb elements similar in general morphol- ogy to that of the co-occurring larger specimens, each displaying a broadly arched posterior process with one or two large denticles (subequal in size to the cusp). However, the small specimens are notably less sinuous than the larger mature specimens. Mature Sa and Sb elements in the higher sample (CQ-762.8) are indistin- guishable from those in the lower sample. However, immature small specimens in this sample are markedly different in two aspects: 1) the posterior process is 76 BULLETIN 369 arched anteriorly, but the process is straight posteriorly (and non-sinuous to slightly sinuous); and 2) the pos- terior process consistently shows only a single large denticle (at the inflection where the anterior arch straightens posteriorly). These morphologies are not generally characteristic of P. flexuosus but more close- ly resemble that seen in P. inflexus Stauffer, 1935 and P. undatus Branson and Mehl, 1933b (see Leslie and Bergstr6m, 1995). It could be argued that these small specimens should actually be assigned to P. inflexus, but this assignment is rejected for two reasons: 1) no larger specimens of P. inflexus occur within any of the St. Peter samples; and 2) the co-occurring small Sc elements (same sizes as the small Sa and Sb elements) are cordylodontiform (dolabrate), unlike the phrag- modontiform Sc elements of P. inflexus (see Leshe and Bergstrom, 1995). If these small Sa and Sb elements (CQ-762.8) belong within the sample of P. flexuosus, it seems reasonable to suggest that significant morpho- logic changes in the phragmodontiform elements first appeared during juvenile ontogenic development in certain (St. Peter?) populations of P. flexuosus. It is proposed that these juvenile morphologies later be- came incorporated in the mature morphology of the descendent species (P. inflexus) by paedomorphosis (paralleling changes in the Pa elements discussed above). If this proposition has any validity, the taxonomic differentiation of P. flexuosus and P. inflexus may prove difficult for small (juvenile) elements. The fol- lowing quote from Klapper et a/. (1981, p. 261, un- derlines added) is of note: “‘The skeletal apparatus of Phragmodus inflexus Stauffer is closely similar to that of its predecessor, P. flexuosus Moskalenko, but differs in being composed of typically much smaller elements that are laterally compressed and commonly fragile rather than large and robust.”’ However, such size dis- tinctions, particularly when co-occurring with larger elements of Phragmodus, may conceivably reflect on- togenetic growth stages of a single species in some cases. An abundance of small specimens in certain samples may alternatively reflect two different things: 1) the specimens represent a species that is character- istically small, or 2) the sample is skewed toward ju- venile specimens, possibly due to high juvenile mor- tality in particular depositional settings. When both small and large elements are present in the same sam- ple, ontogenetic variation should be considered. Bauer (1994) reported that the ranges of P. flexuosus and P. inflexus overlap in the Bromide Formation of Oklahoma. If the small Sa and Sb elements from the St. Peter samples discussed above are assigned to P. inflexus, a similar overlap could also be interpreted. Nevertheless, an ontogenetic explanation of morpho- logic variation within a single species (P. flexuosus) is considered a more likely explanation for the St. Peter samples. The species-level taxonomic assignment of small, presumably juvenile, elements of Phragmodus may inadvertently omit consideration of those distin- guishing characters that appear in later stages of on- togenetic development. This is of special concern if paedomorphic evolution characterizes any portion of the Phragmodus lineage. It is recommended that spe- cies of Phragmodus should ideally be defined by char- acters present in the largest elements of any collection, as such elements likely were derived from fully mature individuals. Phragmodus cognitus Stauffer, 1935 Plate 1, figures 18—23 Discussion.—Elements of Phragmodus cognitus dominate certain collections from the Glenwood Shale of Iowa (e.g., CQ-721, J-1021, SS-753), and the spe- cies also occurs in equivalent strata of the uppermost St. Peter Sandstone or Glenwood Shale in eastern Ne- braska (S-1162) and southeastern Minnesota (Stauffer, 1935). Phragmodus cognitus 1s apparently endemic to the continental interior of North America, and it is best known from the Upper Mississippi Valley area where it ranges as high as the Decorah Shale (Leslie, 2000). It is primarily distinguished from other species of Phragmodus by the presence of an ozarkodiniform Pa element (Leslie and Bergstr6m, 1995; Klapper ef al., 1981), unlike the dichognathiform P elements seen in other species of the genus. The Pb element of P. cog- nitus, however, 1s dichognathiform. Collections con- taining relatively large elements of Phragmodus from CQ-720.3, CQ-721, and SS-753 agree in most salient details with the diagnosis of P. cognitus given by Klapper et al. (1981, p. 251). Most Pa elements are ozarkodiniform, but a few of the largest specimens are aberrant in showing an incipient dichognathiform an- terior process and an expanded basal cavity (PI. 1, fig. 20). The occurrence of a dichognathiform-like process on the largest (presumably gerontic) specimens may indicate convergence towards the Pa structure of P. inflexus or P. flexuosus \ate in the ontogeny of some populations of P. cognitus. Klapper et al. (1981, p. 251) noted “‘riblike expansions of outer side [of Pa element] vertically beneath cusp” for P. cognitus that are reminiscent of a greatly reduced dichognathiform process. They indicated that the S elements of P. cog- nitus display a “straight bladelike’’ process posterior of the arched anterior region, but noted that some spec- imens apparently belonging to this species show “slightly twisted”? denticles. Similar twisting is seen in some specimens from CQ-720.3, CQ-721, and SS- ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER 77 753, and a few fragmentary posterior processes are slightly sinuous (less so than seen in P. flexwosus). Phragmodus cf. P. ambiguus Bauer, 1994 Discussion.—Collections from the lower St. Peter Sandstone of eastern Nebraska (O-1977) and northeast Kansas (C-3387, 3386) include scattered to common elements of a species of Phragmodus similar in most respects to P. flexuosus discussed above. However, un- like the collections of P. flexuosus from the lower St. Peter of western Iowa, only one type of P element was noted in the Nebraska and Kansas samples. The P el- ements from these collections (SUI 99488, SUI 99489) are not particularly well preserved or abundant, but the angle formed by the processes is relatively constant in all specimens (similar to that seen in the Pb elements of P. flexuosus). Where preserved, the posterior pro- cess bears 3 denticles. No broad-angled forms resem- bling the Pa elements of P. flexwosus were noted in these collections. Bauer (1987, p. 25) originally de- scribed forms from the McLish of Oklahoma that lacked differentiated P elements as **P. flexwosus mor- photype B,” and he subsequently named this taxon P. ambiguus Bauer, 1994. The Kansas and Nebraska forms are tentatively allied with this species. Alter- natively, the absence of differentiated Pa elements could be a preservational artifact related to the small collection sizes. The associated M (dolabrate) and S elements are largely indistinguishable from P. flexu- osus 8.8. P. ambiguus is known trom McLish and low- er Bromide formations in Oklahoma and the Chazy Group of New York (Bauer, 1994). Sweet (1992) also reported P. flexuosus morphotype B (= P. ambiguus) from the St. Peter at Locality CT and elsewhere in the Kansas subsurface. Phragmodus cf. P. inflexus Stauffer, 1935 Discussion.—Phragmodus inflexus 1s primarily dis- tinguished from P. cognitus by its dichognathiform Pa element, which may display a denticulate (single den- ticle) anterior process (Leslie and Bergstr6m, 1995; Klapper et al., 1981). Some specimens of Phragmodus from the Glenwood Shale of eastern Iowa (GN) and eastern Nebraska (S-1158, S-1159, S-1161) are not in- cluded within P. cognitus because the Pa elements are dichognathiform, although the anterior process is ad- enticulate and is not as prominently developed as in typical P. inflexus. The associated Phragmodus ele- ments (Pb, M, S) from these collections are largely indistinguishable from those of P. cognitus. Because of the presence of dichognathiform Pa elements, Phragmodus elements from these collections are pro- visionally labeled P. sp. cf. P. inflexus. A single Pa element from CQ-720.3 displays a denticulate anterior process and is assigned to P. sp. cf. P. inflexus, al- though this specimen occurs within collections other- wise dominated by P. cognitus. A denticulate anterior process on one or both of the P elements is given as a diagnostic character of P. inflexus by Klapper et al. (1981, p. 262), but they acknowledged that “anteriorly adenticulate dichognathiform elements that are other- wise closely similar to anteriorly denticulated speci- mens occur in many collections of P. inflexus.”’ As such, it seems probable that the denticulation of the dichognathiform process displays variation within the species. The type specimens of both P. cognitus and P. in- flexus come from the same locality and stratum in the Glenwood Shale of southeastern Minnesota (Stauffer, 1935), and, if both species are valid taxa, they are apparently contemporaneous and sympatric in the North American Midcontinent. Both species succeed P. flexuosus stratigraphically, and immature elements of Phragmodus occur in the underlying St. Peter Sand- stone that resemble both P. cognitus and P. inflexus. The apparent difficulty in differenting P. inflexus and P. cognitus in some Iowa Glenwood collections, and the co-occurrence of these two species in Minnesota, raises issues about their taxonomic status. Geographic and paleo-environmental variations may need to be considered in a regional stratigraphic evaluation of this Phragmodus plexus. Although speculative, the possi- bility that P. inflexus and P. cognitus may be geo- graphic or ecophenotypic variants of a single species is raised here. Phragmodus? species Discussion.—Rare fragmentary elements (SUI 99490, SUI 99491) from the lower St. Peter Sandstone (CQ-775.7, CQ 762.8) resemble forms from the Bro- mide, McLish, and Tulip Creek formations of Oklahoma that Bauer (1994) classified as Phragmo- dus? arcus Webers, 1966. These St. Peter specimens include S elements with erect laterally compressed denticles. Dichognathiform P elements tentatively as- sociated with this taxon possess denticulate processes and a compressed cusp. These forms differ from ?P. arcus discussed by Bauer (1994) in the apparent ab- sence of lateral costae on the S-element cusps, and the P elements are dichognathiform and lack the sharp an- gle between posterior and anterior processes. Phrag- modus arcus was first described by Webers (1966) for certain distinctive phragmodiform S elements from the Platteville Formation of Minnesota. Indeterminate Genus and species C Plate 2, figures 8, 9 Discussion.—Two indeterminate conodont elements with multi-denticulated elongate thin processes were 78 BULLETIN 369 recovered from the lower St. Peter Sandstone in the Offutt Air Force Base core, Nebraska (O-1977). The most complete specimen is carminate, with one long process (anterior?) bearing 15 erect partially-fused denticles and the shorter broken process (posterior?) preserving 6 denticles. A small shallow basal cavity is seen below the cusp. A second specimen is tentatively associated with this form, and displays a broken elon- gate process bearing 13 denticles. The numerous small denticles seen on these specimens invite comparison with other highly denticulated Ordovician taxa, espe- cially Bryantodina and Appalachignathus. However, the St. Peter forms are more highly denticulate than any known species of Bryantodina, and, in addition, Bryantodina characteristically displays a proportion- ately larger cusp and a basal groove than the St. Peter specimens. P elements of Appalachignathus are more highly denticulate than the St. Peter specimens and also display a basal groove, and any relationships seem unlikely. Genus and species C probably represents a new taxon, possibly allied with Bryantodina. Family RHIPIDOGNATHIDAE? Lindstrém, 1970 Genus APPALACHIGNATHUS Bergstrom, Carnes, Ethington, Votaw, and Wigley, 1974 cf. Appalachignathus species Discussion.—A single broken Pb (?) element (SUI 99492) from the St. Peter Sandstone at St. Paul, Min- nesota, preserves 12 semi-erect partially fused denti- cles, and a basal groove extends the length of the spec- imen. The multidenticulate aspect as well as the basal groove suggest similarities with Appalachignathus, a rare but widespread conodont genus from Chazyan and Blackriveran strata of North America (Bergstr6m ef al., 1974). The fragmentary nature of the specimen, however, precludes clear assignment. An additional fragment from the Glenwood Shale (CQ-721) also re- sembles Appalachignathus, but assignment is even more tenuous. Bergstrom et al. (1974) noted the pos- sible presence of the genus in the Glenwood Shale of Minnesota. Indeterminate rhipidognathid? species Discussion.—Small elements from the Glenwood Shale of lowa (CQ-720.3, 721) share some aspects with the Rhipidognathidae. Two types of symmetrical alate elements both display posterior processes re- duced to a sharp ridge. One type has lateral processes bearing a single denticle, whereas the other form has five denticles on each lateral process (the latter grossly resembles Sa elements of Rhipidognathus and Appa- lachignathus). Associated angulate elements are slight- ly arched with a prominent cusp and reduced processes with three or four small denticles; these grossly resem- ble the M elements of Rhipidognathus illustrated by Sweet (1988, p. 76). These types of conodont elements have not been previously reported from the Glenwood Shale, and they likely represent an undescribed taxon, possibly a rhipidognthid. Order PRIONIODINIDA Sweet, 1988 Family CHIROGNATHIDAE Branson and Mehl, 1944 Genus CHIROGNATHUS Branson and Mehl, 1933a Chirognathus duodactylus Branson and Mehl, 1933a Plate 2, figures 4, 5 Discussion.—Elements of Chirognathus duodacty- Jus are Common in many samples from the Glenwood Shale of Minnesota (Stauffer, 1935; Webers, 1966) and Iowa (this study). The apparatus-based species C. duo- dactylus was Clarified by Sweet (1982), who synony- mized a plethora of form species originally named from the Glenwood and Harding formations (Stauffer, 1935; Branson and Mehl, 1933a). The distinctive sym- metrical Sa element (form species ““C. multidens”’) is an elongate element in the lowa Glenwood collections bearing 6 to 8 denticles on each process (e.g., Pl. 2, fig. 4; see also Stauffer, 1935, pl. 9, fig. 40, for Min- nesota Glenwood example). However, additional illus- trated Sa elements from the Harding, Winnipeg, and Glenwood formations (Branson and Mehl, 1933a, pl. 2, fig. 43 type “C. multidens’; Sweet, 1955, pl. 27, fig. 1; Sweet, 1982, pl. 1, fig. 16; Webers, 1966, pl. 5, fig. 2) are less elongate, bearing 6 or fewer denticles per process. Such variations were incorporated within the multi-element species C. duodactylus by Sweet (1982), as followed here. cf. Chirognathus species Plate 2, figures 6, 11 Discussion.—A few small hyaline elements from the St. Peter Sandstone are questionably compared to Chirognathus. Specimens from northeast Kansas (C- 3386; Pl. 2, figs. 6, 11) and western lowa (CQ-775.7) resemble Chirognathus in size, basal development, and denticulation, but these may alternatively represent ju- venile Erismodus. Three small specimens from the Iowa St. Peter (CQ-757) are more clearly identifiable as Chirognathus, including an Sc element and two Sa elements bearing four to five denticles per process. These latter specimens resemble C. duodactylus, al- though they are not presently assigned to this species because of the limited collection. Although Sweet (1984) considered C. duodactylus to be an exclusively ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER 79 Mohawkian conodont, a longer range is indicated for the genus consistent with the St. Peter occurrences. Klapper ef al. (1991, p. 46) noted the co-occurrence of Chirognathus and Phragmodus flexuosus in the “Simpson Group” of south-central Kansas, which they considered the oldest known specimens of the genus. Sweet (1992) subsequently reported C. duodactylus immediately above P. flexuosus in the Kansas subsur- face. Bauer (1994) listed the co-occurrence of C. duo- dactylus and P. ambiguus in the lower Bromide For- mation of Oklahoma. Tipnis et al. (1979) noted Chi- rognathus sp. within the range of P. flexuosus in the Mackenzie Mountains. Genus CURTOGNATHUS Branson and Mehl, 1933b Curtognathus species Discussion.—Small dominantly hyaline elements assigned to an indeterminate species of Curtognathus are noted in only a few samples (Tables 1, 2), but they are moderately common in two lower St. Peter samples (CQ-775.7, 762.8; collections SUI 99493, SUI 99494). Following the recommendation of Leslie (2000, p. 1133) these forms are left in open nomenclature: “‘Un- til the apparatus of the genus is established, there is little point in trying to define apparatus-based species” of Curtognathus. The St. Peter elements show a broad range of morphological intergradation that closely re- sembles that illustrated for “?Curtognathus typus” from the Dutchtown Formation of eastern Indiana by Ethington et al. (1986). Curtognathiform, trucherog- nathiform, and cardiodelliform elements are recog- nized, but polycaulodiform elements were not recov- ered. Although dominantly hyaline, some specimens preserve traces of white matter in the denticle tips. Genus ERISMODUS Branson and Mehl, 1933a Erismodus species Plate 3, figures 1-3, 7, 9, 10, 12-15, 17-21; Plate 4, figure 11 Discussion.—Hyaline elements included in unas- signed species of Erismodus are among the most abun- dant conodonts found in the St. Peter Sandstone and Glenwood Shale, and a bewildering array of forms are present. Following the advice of Leslie (2000, p. 1135), until a full revision of Erismodus and its con- tained species is completed, it is advisable to leave most forms in open nomenclature, as “‘assigning ele- ments of the plexus a formal specific name is not deemed appropriate.’’ As observed by Andrews (1967, p. 890) in the Joachim Dolomite of Missouri, many elements of Erismodus show a “high degree of intra- specific variability’ and some collections display a “complete gradation” in morphology between many previously-defined form species. Elements of Erismo- dus occur in almost all productive samples used in this study, and Erismodus is the dominant conodont in some St. Peter samples (CQ-757, O-1977, H-3579, SP- L). Many hundreds of specimens were recovered, and a representative selection is illustrated on Plate 3. Sweet (1982) diagnosed Erismodus with a septimem- brate apparatus, and he synonymized many form taxa originally described from the Glenwood Shale (Stauf- fer, 1935; Webers, 1966) within the multi-element spe- cies E. quadridactylus (Stauffer, 1935). Most speci- mens recovered from the Glenwood Shale during this study are probably assignable to E. quadridactylus. However, many specimens from the St. Peter Sand- stone collections do not conform to the diagnosis of FE. quadridactylus, and additional species are probably represented. In addition to E. quadridactylus, several additional multi-element species of Erismodus have been proposed from Ordovician strata of the North America, including FE. arbucklensis, E. typus, and E. radicans (see discussions in Bauer, 1987, 1994; Leslie, 2000). Some St. Peter specimens resemble elements of these species, but additional forms also seem to be present. Several generalized morphologic categories are rec- ognized in the St. Peter Erismodus collections: 1) large robust forms with relatively thick rounded denticles and cusps, Sa-Sb elements show a prominent down- ward-projecting process (“boss”) beneath the cusp (PI. 3, figs. 1, 18); 2) gracile forms with slender elongate pointed denticles and cusps, generally circular in sec- tion (Pl. 3, figs. 2, 3, 15, 20); 3) gracile forms with variably costate laterally compressed denticles and cusps (PI. 3, figs. 12, 14); 4) forms with widely spaced denticles and broadly expanded basal cavities, some with an aboral “boss” (Pl. 3, figs. 10, 21); and 5) relatively squat forms with short closely-spaced den- ticles and shortened cusps (Pl. 3, fig. 7). Although a full analysis of the St. Peter collections has not been undertaken, some of these categories share morpho- logic similarities with previously recognized species, including E. typus (category 1), E. radicans, E. asym- metricus, and E. symmetricus (category 2), and E. ar- bucklensis and E. quadridactylus (category 3). Collec- tions from the lower St. Peter include common Eris- modus elements (Pl. 3, figs. 12, 14, 19) that more closely resemble EF. arbucklensis, a species originally described by Bauer (1987) from the McLish Formation of Oklahoma, than FE. gquadridactylus. Additional ele- ments with widely spaced denticles and broadly ex- panded basal cavities (category 4) cannot be clearly associated with any presently-defined multi-element species, but these share some similarities with the form BULLETIN 369 ST. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER 81 species E. expansus (Branson and Mehl, 1933b:; see also Andrews, 1967). The relatively squat elements (category 5) do not clearly resemble any named form species, suggesting that an unnamed taxon likely oc- curs in the St. Peter faunas. Additional robust forms (e.g., Pl. 4, fig. 11) are tentatively included with Er- ismodus. Genus ERATICODON Dzik, 1978 Erraticodon species Plate 2, figure 15; Plate 3, figures 4—6, 8, 11, 16: Plate 4, figures 12—24 Discussion.—Hyaline elements characterized by long slender pointed denticles and that differ in mor- phologic details from those included in Erismodus are here assigned to an unnamed species of Erraticodon. Elements of Erraticodon sp. are scattered to common in collections from the lower to middle St. Peter Sand- stone (CQ, O-1977, CT), and a few specimens from the upper St. Peter (CQ-739) are tentatively included as E. sp. However, Erraticodon is absent in all Glen- wood Shale collections. Post-Lower Ordovician oc- currences of Erraticodon include E. balticus Dzik from Europe, Australia, and Arkansas (Dzik, 1978; Watson, 1988; Leslie et al., 2000), ?E. balticus from Newfoundland (Stouge, 1984), E. sp. cf. E. balticus from Oklahoma and Kansas (Bauer, 1987; Sweet, 1992), E. aff. E. balticus from Utah and Alabama (Eth- ington and Clark, 1981; Shaw er al., 1990), and E. sp. from Nevada (Harris et al., 1979). E. sp. from the St. Peter does not clearly conform to any of these illus- trated forms. Pending a complete re-evaluation of the genus, the St. Peter specimens likely comprise a new species. Erraticodon apparently possesses a septimem- brate apparatus (Watson, 1988). In general, the St. Pe- ter Erraticodon sp. differs from these other occurrenc- es in showing reduction or loss of the third (lateral or posterior) processes on the Pa, Sba, Sbb, and Sa ele- ments and a general expansion of the basal cavity. In addition, the interpreted M element of the St. Peter species does not appear to be dolabrate as in the other occurrences. Such contrasting morphologies, as well as the general morphologic plasticity of elements dis- played in the collections, have made homologies of the St. Peter elements difficult to constrain. Nevertheless, an attempt has been made to follow the elemental no- tation of Bauer (1987). It is possible that some of the non-homologous elements here included in the appa- ratus may belong to other unnamed or unrecognized taxa. The interpreted Pa element of the St. Peter species (Pl. 3, fig. 4; Pl. 4, figs. 12, 13, 15, 16) resembles that of Erraticodon cf. E. balticus from the McLish For- mation (Bauer, 1987), but most specimens lack the very short, adenticulate lateral process of that form. However, one specimen (from CQ-775.7) does display PLATE 3 All figures (photographs) *40. Specimens lightly coated with ammonium chloride sublimate. 1-3, 7, 9, 10, 12-15, 17-21. Erismodus spp. 1. Sc element; SUI 95060, OF (O-1977). Wn Se Wwnowon 4-6, 8, 11, 16. Erraticodon sp. ns aes n= 0 Se element; SUI 95061, CQ-776.7. Se element; SUI 95062, CQ-762. . indeterminate robust element; SUI 95063, OF (O-1977). Sc element; SUI 95064, CQ-762. . robust Sa element; SUI 95065, CQ-776.7. . Sb? element; SUI 95066, CT (C-3387). . Pb? element; SUI 95067, SP-L (9-10.5). 4. Sba element; SUI 95068, CQ-762. 15. Sba element; SUI 95069, CQ-762. 17. Sa element; SUI 95070, CQ-776.7. 18. Sa element; SUI 95071, CT (C-3387). 19. Sbb element; SUI 95072, CQ-762. 20. Sbb element; SUI 95073, CQ-762. 21. Sa element; SUI 95074, CQ-776.7. . Pa element (broken); SUI 95075, CQ-762. M? element; SUI 95076, CQ-776.7. cusp, Sba? element; SUI 95077, CT (C-3387). Sc element; SUI 95078, CQ-762. . Pb element; SUI 95079, CQ-776.7. . Pb element; SUI 95080, CQ-776.7. St. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER 83 a short adenticulate lateral process. The posterior pro- cess is long with four to seven slender reclined den- ticles. The short anterior process bears one to two den- ticles, and the proximal denticle is costate and sube- qual in size to the cusp. The Pa element bears a su- perfical resemblance to the Sc elements of Erismodus, but the large anterior denticle and the long posterior process serve to distinguish them. Pb elements are tentatively included with the St. Pe- ter species (Pl. 3, figs. 11, 16), but these forms also resemble Pb elements of Erismodus and may alterna- tively belong there. Unlike the Pb element of Errati- codon sp. cf. E. balticus from the McLish Formation (Bauer, 1987), the St. Peter form shows a more broadly developed basal cavity. The element is arched, with one elongate process (6—9 denticles decreasing in size distally) and one shorter process (2—4 denticles). The cusp is slender and round to compressed in cross-sec- tion. The M elements included within the genus Errati- codon have been described to be dolabrate (““neoprion- iodiform’’) in most previous investigations. With the possible exception of one small fragmentary indeter- minate specimen, however, no dolabrate elements are associated with the St. Peter E. sp. Instead, a co-oc- curring distinctive bipennate or digyrate element (PI. 4, fig. 19; Pl. 3, fig. 5) is tentatively interpreted to represent the M element of the St. Peter species. This element bears a superficial resemblance to the M ele- ment of E. guadridactylus illustrated by Bauer (1994), but it possesses an enlarged basal cavity. The basal cavity shows a large lateral bulge beneath the cusp. Of six specimens recovered, only one preserves a small posterior (?) process that bears four tiny denticles, but on the other specimens this process is greatly reduced or broken. The Sa element is alate (Pl. 4, fig. 17) and displays a distinctive knife-like cusp with a sharp posterior margin. The cusp is offset posteriorly with respect to the two lateral processes, and its sharp-edged margin expands basally to form a short pointed adenticulate posterior process. The basal cavity is relatively deep PLATE 4 All photographs X40. Specimens lightly coated with ammonium chloride sublimate. 1, 2, 6, 7. Drepanoistodus suberectus (Branson and Mehl, 1933b) il. 5 homocurvatiform element; SUI 95081, SM (S-1162). geniculate coniform element (aff. D. angulensis); SUI 95082, CQ-776.7. 6. homocurvatiform element; SUI 95083, CQ-776.7. 7. suberectiform element; SUI 95084, SM (S-1162). 3. Stereoconus sp. 3. coniform element; SUI 95085, CQ-739. 4. Panderodus sp. 4. coniform element: SUI 95086, SM (S-1162). 5. Oneotodus? ovatus (Stauffer, 1935) 5. coniform element; SUI 95087, SP-L (10.5—12). 8, 9. Mixoconus sp. 8. sub-erect coniform element; SUI 95088, SP-U (27—28.5). 9. reclined coniform element; SUI 95089, SP-L (9—10.5). 10. Staufferella sp. cf. S. falcata (Stauffer, 1935) 10. symmetrical element, broken base; SUI 95090, CQ-776.7. 11. Erismodus sp. 11. robust Pa? element; SUI 95091, CQ-762.8. 12-24. Erraticodon sp. 12. 13: 14. 15. Pa element; SUI 95092, CQ-762. Pa element; SUI 95093, CQ-762. Sc element; SUI 95094, CQ-776.7. broken Pa? element with cusp and anterior denticle; SUI 95095, CT (C-3386). . broken Pa element with cusp and anterior denticle; SUI 95096, CT (C-3386). . Sa element; SUI 95097, CT (C-3387). . Sbb? element; SUI 95098, CQ-776.7. . M? element; SUI 95099, CQ-776.7. . Sba? element; SUI 95100, CQ-776.7. . Sba? element; SUI 95101, OF (O-1977). . Sc? element; SUI 95102, CQ-776.7. . Sc? element; SUI 95103, CQ-776.7. . Sba? element; SUI 95104, CQ-776.7. 84 BULLETIN 369 and roughly triangular in outline. This Sa element dif- fers from other species of Erraticodon in lacking den- ticulation of the posterior process. The sharp-edged knife-like cusp is distinctive even in broken speci- mens, and a number of such broken specimens are identified in the St. Peter collections. The lateral pro- cesses are short and possess two to three denticles. Two types of Sb elements (Sba, Sbb) are recognized in the St. Peter species. The Sba element (PI. 4, figs. 20, 21, 24) differs from the homologous element of E. cf. balticus from the McLish Formation (Bauer, 1987) in showing a greatly reduced posterior process. In some specimens the posterior process is reduced to a short adenticulate point or node similar to that seen in the Sa element. However, some specimens from the lowest samples of the CQ core (CQ-776.7) display one to two small denticles fused to the lower part of the cusp. The presence of these posterior denticles clearly allies the St. Peter form with Erraticodon (and not Erismodus), and in this respect resembles the reduced posterior process of the illustrated “‘plectospathodi- form” element of E. balticus and E. aff. E. balticus with one or two denticles (see Dzik, 1978; Watson, 1988; Ethington and Clark, 1981). The cusp 1s laterally compressed and offset posteriorly with respect to the adjoining lateral processes. The cusp is costate and displays a sharp-edged posterior margin (PI. 3, fig. 6) similar to that of the Sa element. The lateral processes angle downward from the cusp and are of subequal length but show asymmetric denticulation. One pro- cess generally has larger and longer cusps than the other (Pl. 4, fig. 24). Most specimens bear four den- ticles on each process, but the number of denticles varies from three to seven in the St. Peter collections. The interpreted Sbb element (PI. 4, fig. 18) of the St. Peter species is digyrate, and displays a long point- ed costate cusp. The lateral processes are highly asym- metric, and the longer one is bent outward about 130° from the axial plane of the cusp. The larger lateral process bears five slender denticles that decrease in size laterally. The smaller lateral process is greatly re- duced and includes two small denticles attached di- rectly to the lower portion of the cusp. The posterior process is reduced to a pointed nub at the base of the cusp similar to that of the Sa, Sba elements. The interpreted Sc elements (PI. 4, figs. 22, 23) of Erraticodon. sp. from the St. Peter Sandstone are dis- tinctive bipennate forms generally with a long curved cusp and a prominent posterior process bearing six to eight elongate denticles. The cusp is roughly circular in cross-section, and in one specimen the cusp is re- duced to a squat rounded knob. The preservation in many specimens of small relict denticles or nodes fused along one side of the lower cusp belies the pres- ence of a greatly reduced anterior (or lateral) process. Variably one or two relict denticles or nodes are pres- ent, completely fused their entire length onto the cusp. Except for the preservation of these relict denticles, the element would appear dolabrate. A few specimens show discrete and more elongate anterior denticles along the cusp margin (PI. 4, fig. 14; Pl. 3, fig. 8). Order UNKNOWN Family COLEODONTIDAE Branson and Mehl, 1944 Genus ARCHEOGNATHUS Cullison, 1938 Archeognathus species Plate 2, figures 18, 21, 23 Discussion.—Fragmentary elements from the St. Peter Sandstone (CQ-776.7, 775.7, 762, 755.5; SP-L, SP-U, C-3386) characterized by relatively large, robust suberect to slightly reclined fibrous denticles with a basal groove are assigned to Archeognathus sp. These are likely conspecific with A. primus Cullison, 1938, from the Dutchtown Formation of Missouri (described in detail by Klapper and Bergstré6m, 1984), but the absence of complete specimens that preserve the char- acteristic basal structure precludes a species-level as- signment. The denticles of Archeognathus are gener- ally discrete but are interconnected along the basal groove by thin laminae (ibid.). This fragile basal in- terconnection is displayed on the St. Peter specimens, both broken and multi-denticled specimens (see bases of Pl. 2, figs. 18, 21). Klapper (in Klapper and Bergs- trém, 1984, p. 968) had previously examined speci- mens from the CQ core in western Iowa and suggested that specimens Witzke (1980, p. 5) had labeled as Neo- coleodus (from CQ-762, 721) may represent Archeog- nathus. cf. Archeognathus species Plate 2, figures 19, 20, 22 Discussion.—Most specimens of Archeognathus primus display a series of discrete unfused denticles interconnected by thin basal laminae (Klapper and Bergstrom, 1984). Specimens from the St. Peter Sand- stone and Glenwood Shale that display partially fused denticles along an expanded basal bar are tentatively designated as cf. Archeognathus sp. (see Tables 1, 2). These specimens display denticles of similar size and structure to those included in A. sp. and possess a basal groove similar to that seen in Coleodus. The partially fused denticles of these forms bear resemblance to por- tions of the crown of one specimen of A. primus de- scribed by Klapper and Bergstr6m (1984, p. 956), which includes a segment with four denticles “‘fused St. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER to midheight.”” That specimen clearly demonstrates that Archeognathus can variably display multi-dentic- ulate segments with partially fused denticles, lending credence to the inclusion of similar St. Peter and Glen- wood specimens within the genus. Genus COLEODUS Branson and Mehl, 1933a Coleodus species Plate 2, figures 13, 14, 16, 17 Discussion.—Collections from the St. Peter Sand- stone of western Iowa (CQ-7765.7, 762.8, 762, 739), Minnesota (SP-L), and Nebraska (O-1977) contain scattered distinctive blade-like multi-denticulated hy- aline elements with a basal trough. These specimens are included within the genus Coleodus, but species resolution is hampered by wide morphological varia- tions within the collections as well as the lack of a modern systematic evaluation of previously described species. A number of form species of Coleodus have been described from North America and Siberia based largely on denticulation and profile, but intraspecific variability within these forms remains largely unstud- ied and an apparatus-based reconstruction has not been proposed. However, Ethington er al. (1986, pp. 13-15) raised the possibility that a variety of forms (including the form species C. simplex and C. delicatus) may be “parts of an apparatus” of a single species. Their pro- posal seems reasonable, and it is possible that many of the forms and form species of Coleodus should be included within a single multi-element species. They further recognized two distinct types of elements as- sociated with another species (C.? sp. C), suggesting that Coleodus and related forms contained multi-ele- ment apparatuses. Klapper and Bergstrom (1984, p. 974) “considered the possibility that [Coleodus and Archeognathus| were elements of the same appara- tus,” but this idea “requires additional evidence.” Elements included in Coleodus from the St. Peter Sandstone display morphologic variations categorized as follows: 1) long straight-bladed forms for most of length, relatively uniform denticulation, denticles fused except at tips, denticles uniformly reclined, rel- atively deep basal trough (PI. 2, fig. 13); 2) long slight- ly curved or arched multi-denticled forms, uniform height for most of length (diminishes posteriorly), small denticles mostly fused except at tips (may be completely fused in anterior or posterior regions), den- ticles reclined at similar angle, basal trough shallow and narrow (Pl. 2, fig. 16); 3) short slightly arched forms with few denticles (6-9), height and width varies with length (tapers posteriorly), denticles of nonuniform size, fused except at tips, denticles vari- io.) Nn ably reclined (angle decreases posteriorly, i.e., less erect), broad shallow basal trough (PI. 2, fig. 14); 4) similar to category 3 except denticles increase in size and become more erect posteriorly, denticles variably fused and discrete (PI. 2, fig. 17); 5) relatively straight forms with discrete unfused sub-vertical denticles, prominent basal trough: 6) relatively straight forms with completely fused denticles (denticles may be in- distinguishable), upper margin forms ridge or blade, prominent basal trough: and 7) relatively straight forms, narrow bar at base bearing large sub-erect to curved discrete denticles, shallow basal trough (PI. 2, fig. 12). It remains speculative whether these morpho- logic variations represent more than one species of Co- leodus, or whether these forms can all be accommo- dated within a single multi-element species concept. If the latter option is followed, most of these forms should probably be referred to C. simplex Branson and Mehl. Some of the morphologic categories of Coleodus recognized in the St. Peter collections resemble forms described from other localities, but the species-level classification of these previously-described forms re- mains confusing. Coleodus simplex, the type species of the genus, was originally described by Branson and Mehl (1933a) from the Harding Sandstone of Colo- rado, and their cotypes have broadly arched blades bearing a completely fused fine vertical denticulation. However, Branson and Mehl (1933a, pl. 1, figs. 23) also included straight-bladed forms bearing slightly re- clined denticles (unfused at tips) within C. simplex (these forms resemble St. Peter category 1). Similar morphologies were also assigned to C. simplex from the Dutchtown Formation of Missouri (Youngquist and Cullison, 1946, pl. 90, fig. 16), the St. Peter Sandstone of Indiana (Rexroad ef al., 1982, pl. 2, fig. 12), anda queried reference from the Dutchtown Formation of Indiana (Ethington ef al., 1986, pl. 2, fig. 26). Addi- tional material referred to C. simplex includes slightly arched forms with nonuniform reclined denticles (un- fused at tips) from the Tyner of Oklahoma (Bauer, 1989, fig. 4.5), straight forms with large unfused dis- crete nonuniform reclined denticles from the St. Peter Sandstone of Indiana (Rexroad er al., 1982, pl. 2. fig. 11), and arched forms with completely fused vertical denticles from Siberia (Moskalenko, 1970, pl. IX, fig. 8). As a form-species concept, it is clear that C. sim- plex has been used by various authors to encompass a broad range of morphologic variation. Branson and Mehl (1933b) described additional form species of Coleodus from the Joachim Formation of Missouri, C. delicatus and C.? levis. Coleodus de- licatus has a broadly arched profile with strongly re- 86 BULLETIN 369 clined to curved fused denticles (inclination decreases posteriorly, t.e., less erect). Similar forms have been assigned to Coleodus delicatus from the Harding, Win- nipeg, and Dutchtown formations (Sweet, 1955, 1982; Ethington er al., 1986). C. pectiniformis was proposed as a new species from the Dutchtown Formation by Youngquist and Cullison (1946) for a form similar to C. delicatus but with a more arched blade and slightly less fused denticles; synonymy with C. delicatus seems likely. Similar forms from the Rockcliffe For- mation of Ontario were assigned to C. pectiniformis by Copeland er al. (1989), who also included a spec- imen with largely unfused discrete curved denticles within the species. Forms included within Coleodus show significant variation in the fusion of the denticles along the blade: 1) completely fused with indistin- guishable denticulation (as for C.? levis), 2) complete- ly fused denticles but individual denticles outlined by shallow furrows (like type C. simplex), 3) mostly fused denticles but with distal margins free (e.g., C. delicatus and many referred C. simplex), 4) partially fused den- ticles dominate but blade bears some unfused discrete denticles (e.g., C.? sp. C Ethington et al/., 1986), and 5) unfused discrete denticles along most or all of blade (e.g., Rexroad et al., 1982, pl. 2, fig. 11; C. confinus Moskalenko, 1970). This spectrum of denticular fusion is also displayed in the St. Peter collections used for this study. A form with largely discrete denticles “‘much like Coleodus” from the Harding Sandstone was designat- ed a new genus and species by Branson and Mehl (1933a, p. 24), Neocoleodus spicatus. The status of this taxon remains uncertain, but the holotype is not congeneric with Archeognathus (Klapper and Bergs- trom, 1984, p. 968). As originally noted by Branson and Mehl (1933a), N. spicatus (holotype) shares sim- ilarities with Coleodus and conceivably may be syn- onymous. In particular, some forms included within categories 4 and 5 above (e.g., Rexroad et al., 1982, pl. 2, fig. 11; this study Pl. 2, fig. 17) display dentic- ulation similar to that seen in N. spicatus. Other forms assigned to various species of Neocoleodus (e.g., Youngquist and Cullison, 1946; Moskalenko, 1970) are more likely referable to Archeognathus (Klapper and Bergstrom, 1984, p. 968). An additional form from the St. Peter Sandstone of western Iowa (PI. 2, fig. 12) bears discrete denticles above a thin bar. The specimen displays a shallow basal trough and is ten- tatively labeled as cf. Coleodus sp., but it may alter- natively be allied with Archeognathus or represent a new taxon. The denticles are smaller and more gracile than those described for Archeognathus (Klapper and Bergstrom, 1984). Genus MIXOCONUS Sweet, 1955 cf. Mixoconus species Plate 4, figures 8, 9 Discussion.—Erect to reclined or slightly recurved coniform elements that bear longitudinal grooves and carinae are the second most abundant type of conodont elements recognized from the lower St. Peter shale unit at St. Paul, Minnesota (Loc. SP). The bases are unex- cavated or show a very shallow excavation. The ele- ments all flare outward to the basal margin forming one of two basal outlines. One type displays a circular or nearly circular basal outline (PI. 4, figs. 8, 9); some specimens are slightly lobate on the anterior surface. The other type shows an ovoid basal outline that is slightly lobate in anterior and posterior directions. The grooved and carinated character of the cusp and the slightly lobate aspect of the basal area are features shared with Mixoconus, and the St. Peter specimens are provisionally allied with that genus. However, the type and only described species of Mixoconus, M. pri- mus Sweet, 1955, is decidedly more lobate than the St. Peter forms (especially anteriorly) and displays more prominent rounded carinae. The St. Peter forms also share similarities with certain coniform Siberian species included within Stereoconus (especially S. cir- culus, S. turaensis, S. bicostatus) by Moskalenko (1970). The generic assignment of these Siberian forms is questionable, however, as the circular to ovoid basal areas and the circular to broadly ovoid cross sec- tion of the carinated cusps differ significantly from the type description of Stereoconus from the Harding Sandstone (Branson and Mehl, 1933a). Pending further study, the St. Peter and Siberian forms should probably be included within one or more new taxa. Genus STEREOCONUS Branson and Mehl, 1933a Stereoconus species Plate 4, figure 3 Discussion.—A few specimens of fibrous laterally- compressed recurved coniform elements from the St. Peter Sandstone of western Iowa (CQ-739) and Min- nesota (SP-L, SP-U) are considered to belong to an unassigned species of Stereoconus. The surfaces are smooth, and the base displays a shallow basal depres- sion with rounded to slightly bulbous basal margins. The St. Peter specimens bear resemblance to the form species S. robustus Branson and Mehl, 1933a. Order and Family UNKNOWN Indeterminate Genus and species A Plate 1, figures 1, 5 Discussion.—Four pectiniform elements from the lower St. Peter Sandstone (CQ-776.7) are not assigned St. PETER-GLENWOOD CONODONTS: WITZKE AND METZGER 87 to any named taxon pending further comparative study. All specimens show one or two prominent ad- enticulate lateral processes extending downward and outward from the cusp, and all possess a basal groove under the full length of the element. The elements are albid, with white matter most abundant in the denticles and cusps. The largest and most complete specimen (Pl. 1, fig. 1) is a pastinate P element with a slightly bulbous lateral process. The cusp is proclined with a short anterior process (3 short denticles) and a more elongate posterior process (4 large suberect denticles, 3 small distal denticles); the distal region of the pos- terior process is bent inward forming a hook-like curve. A second nearly complete specimen (PI. 1, fig. 5) is similar, but it is pastinate with two short adenti- culate lateral processes. The anteror process possesses four small denticles, and the broken posterior process retains three large sub-erect denticles. 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Relative sea-level changes during Middle Ordovician through Mississippian deposition in the Iowa area, North American craton. in Paleozoic sequence stratigraphy, views from the North American craton. B.J. Witzke, G.A. Ludvigson, and J. Day, eds., Geological Society of Amer- ica, Special Paper 306, pp. 307-330. Youngquist, W., and Cullison, J.S. 1946. The conodont fauna of the Ordovician Dutchtown For- mation of Missouri. Journal of Paleontology, vol. 20, pp. 579-590. Appendix.—Locality Register, St. Peter-Glenwood conodont collections. Loc. CQ. Camp Quest core D-21, Lemars; NW SW NW SW sec. 2, T92N, R45W, Plymouth Co., Iowa (stored at lowa DNR-Geological Survey). See Table 1 and Text-figure | for sample depths. Loc. QM. Quimby core, NW NW NE sec. 34, T9ON, R41W, Cherokee Co., Iowa (stored at Iowa DNR- Geological Survey). Basal St. Peter sampled by T. H. Shaw. Loc. PT. Peterson No. | core, Vincent, Northern Nat- ural Gas; NE NE NE NW sec. 10, T 90 N, R 27 W, Webster Co., Iowa (stored at lowa DNR-Geological Survey). Sample depth 1209 ft, Glenwood Shale. Loc. DL. Hummell No. | core, Adel, Northern Natural Gas, NE NW NW sec. 18, T 79 N, R 28 W, Dallas Co., Iowa (stored at lowa DNR-Geological Survey). Sample depth 1747-1749 ft (D-1748), Glenwood Shale. Loc. SS. SS-9 core, Millbrook Farms, Cominco; NW NE NE sec. 29, T 84 N, R 1 E, Jackson Co., Iowa (stored at lowa DNR-Geological Survey). Sample depth 753 ft (SS-753), Glenwood Shale. Loc. CC. Cairo-Columbus Junction gas storage struc- ture, A. Jordan No. 1 core; SW NW NW SW sec. 32, T 75 N, R 4 W, Louisa Co., Iowa (stored at Iowa DNR-Geological Survey). Sample depth 1021 ft (J-1021), Glenwood Shale. Loc. GN. Guttenberg North, Great River Road X-56 roadcut; NE SW NW sec. 32, T 93 N, R 2 W, Clay- ton Co., Iowa. Productive sample 1.2 ft below top of Glenwood Shale. Loc. SP. St. Paul, core 8099, Minnesota Geological Survey; NE NW NE sec. 6, T 28 N, R 22 W, Ram- sey Co., Minnesota. Samples collected by Olsen (1976) from shale unit about 45 ft above base of St. Peter Sandstone; SP-L includes lower samples (la- beled 0 to 13.5”); SP-U includes upper samples (la- beled 19.5—38.5"). Loc. SM. Smith No. 1, Northern Natural Gas; SW SE SW sec. 23, T 13 N, R 11 E, Sarpy Co., Nebraska (stored at Univ. Nebraska, Conservation and Survey Division). Sample depths 1158.3, 1159, 1161, 1161.8 ft (S-1158, S-1159, S-1161, S-1162), Glen- wood Shale or upper St. Peter. Loc. OF Offutt Air Force Base core, U.S. Army Corps Of Engineers; SE SE NW, secadil= ala iNG@Ro3°B. Sarpy Co., Nebraska (stored at Univ. Nebraska, Conservation and Survey Division). Sample depths 1949 ft (O-1949), Glenwood Shale; 1977 ft (O- 1977), St. Peter Sandstone. Loc. HS. Hustead No. A-1 core; SE NE SE sec. 2, T 2 N, R 16 E, Richardson Co., Nebraska (stored at Univ. Nebraska, Conservation and Survy Division). Sample depth 3579 ft (H-3579), St. Peter Sandstone; barren samples 3562, 3562.7, 3583.2 ft. Loc. CT. Carter No. 2-A Davis core; sec. 33, T 13 S, R 10 E, Wabaunsee Co., Kansas (stored at Kansas Geological Survey). Sample depths 3323 ft (C- 3323), “Glenwood”; St. Peter samples 3358.2 ft (barren), 3358.7 ft (barren), 3381—3381.8 ft (bar- ren); 3386 ft (C-3386), 3387 ft (C-3387). See also “Unit A” fauna reported by Sweet (1992). SCOTCH GROVE—LAPORTE CITY CONODONTS: METZGER 93 CONODONT BIOSTRATIGRAPHY OF THE SCOTCH GROVE AND LAPORTE CITY FORMATIONS (LATE LLANDOVERY-EARLY WENLOCK; SILURIAN) IN EASTERN IOWA RONALD A. METZGER Department of Geology Southwestern Oregon Community College 1988 Newmark Coos Bay, Oregon 97420-2912, U. S. A. email: rmetzger@socc.edu ABSTRACT Conodont faunas from the Scotch Grove—LaPorte City formations allow correlation to an interval in the Silurian standard conodont zonation ranging from the eopennatus Zone to within the Ozarkodina sagitta rhenana Superzone (Llandovery to lower Wenlock). The relationship between units in this study is complicated by both the presence of lateral facies relationships and diagenetic controls on the carbonate rocks in the study area. There does not appear to be a lithologic control on sparse conodont faunas. ACKNOWLEDGMENTS The author would like to thank Gilbert Klapper for his support and guidance in all aspects of paleontolog- ic research including instruction with photography while the author was a graduate student at The Uni- versity of Iowa. Most, if not all, conodont workers of the last several decades are familiar with Gilbert’s work ethic that has resulted in publication on a wide array of topics in paleontology and stratigraphy. With a cautionary eye on the recent comments that have been expressed on CONNEXUS towards the future of Paleontology, I would like to point out a facet of Gil’s career that may be overlooked by some, and that is his dedication to the classroom. While cognizant that I will never have a published record to match that of my advisor, I take pride in the fact that as Gil’s last Ph.D. student I may continue part of his tradition of excellence with a commitment to that noblest of pro- fessions: teaching. B. J. Witzke provided field assistance collecting the Delhi samples, allowed access to collections from the other localities in this study, and provided critical re- view of an early version of the manuscript. M. Kleff- ner provided assessment and insight on several taxo- nomic identifications. A portion of the page charges for publication of this manuscript have been provided by the Southwestern Oregon Community College Ge- ology Club. Thanks to James Barrick and Mark Kleff- ner for constructive reviews of the manuscript; of course they are not responsible for any errors of in- terpretation. INTRODUCTION Silurian carbonate rocks of eastern Iowa have been the subject of extensive lithostratographic study for over the past 150 years. The study area includes both outcrop and subsurface samples from eastern Iowa (Text-fig. 1). Earlier biostratigraphic analysis of the section has focused on brachiopod faunas, with limited attention being focused on conodont analysis for the sequence. The lowest occurrence of the brachiopods Pentameroides subrectus and Costistricklandia castel- lana in Iowa are suggestive of a mid- to late Telychian (late Llandovery; C; to C,) age (Johnson, 1979). The graptolite Monograptus priodon has been reported from the middle of the Scotch Grove in the Garrison Core (Witzke, 1981a). Unfortunately, the long range of this species (Telychian to Homerian) does not allow a correlation to the Silurian graptolite zonation. A paucity of conodont work can be attributed to the dominance of nearshore carbonates and pervasive do- lomitization. The sample coverage for most sections is minimal (Text-fig. 2), with the Delhi West Roadcut (DLH) having the most complete sample coverage for the section. Average sample sizes for the Delhi (DLH) section is 4 kilograms (core sample sizes were not available) and provided yields of, at most, one to two well-preserved platform elements per kilogram. The sample coverage includes samples from the lower and middle section of the LaPorte City Formation, and the Johns Creek Quarry, Welton, Buck Creek Quarry, and Waubeek members of the Scotch Grove Formation. Additionally, a sample from the overlying Gower For- mation is included. Although conodont yields are min- imal, the presence of some biostratigraphically diag- nostic species establishes an age for the Scotch Grove— LaPorte City sequence of eopennatus Zone through Ozarkodina sagitta rhenana Superzone of the Silurian Standard Conodont Zonation (Text-fig. 3). Further, this 94 BULLETIN 369 Silurian Limestone Silurian Dolomite Outcrop Pain mel Text-figure 1.—Locality Map. Locality abbreviations: GR (Garrison Core), H13 (Highway 13 section), BF (Bailey’s Ford section), DLH (Delhi West Section), JCQ (Johns Creek Quarry), WBK (Waubeek section), HNQ (Hanken Quarry), BN (Baldwin North), FMQ (Freeman Quarry) and BSQ (Beuse Quarry). See appendix for detailed locality information study will allow for preliminary correlations to be made with sections in basins further east that have been part of continuing work by Kleffner (1987, 1990, 1991, 1994), STRATIGRAPHY Study of the Silurian sequence in lowa dates back to work by David Dale Owen in the 1840s and 1850s when he correlated strata to the Clinton and Niagara groups of New York state. The stratigraphic units con- tinued to be defined by New York nomenclature until the late 1890s, with the exception of the LeClaire Limestone (Hall and Whitney, 1858). During the late 1890s and into the early twentieth century, the Lowa Geological Survey published new formal and informal stratigraphic units for the Silurian thereby developing a regional startigraphy removed from the New York based nomenclature. This study focuses on the Scotch Grove Formation (Text-fig. 4), a unit that was informally introduced by Witzke (198la, 1983) and formally introduced by Witzke (1985) for the ““cherty dolomite interval above the Picture Rock Member and below the base of the laminated and mounded dolomites of the Gower For- mation.”’ The LaPorte City Formation is dominated by limestone units in central Iowa that are correlative to SCOTCH GROVE—LAPORTE CITY CONODONTS: METZGER 95 FORMATION ro) a o = x Ww Ww a =) =< = FORMATION position of Monograptus pnodon (CP core) U0 VU UlTu Uru ) om WW = a Ww = n Ww fa) Cc Cc < =) o x WW Ww a (3) x S) =) ao Ww > fe) c 12) 25 Oo Ee ie) 16) no WELTON MBR Dy LL OLOLOmMOMmO Ulu -Un “OlEUcU Conodont P = Pentameroides Sample C = Costistricklandia FORMATION Text-figure 2.—Stratigraphy, position of conodont samples, oc- currence of brachiopod and graptolite taxa. GR (Garrison Core), H13 (Highway 13), BF (Bailey’s Ford), DLH (Delhi West road cut), HNQ (Hanken Quarry), BN (North Baldwin), JCQ (Johns Creek Quarry), WBK (Waubeek), BSQ (Beuse Quarry) and FMQ (Freeman Quar- ry). Brick pattern represents limestone (LaPorte City Formation), lack of pattern represents dolostone (Scotch Grove Formation). the dolomitized upper Hopkinton and Scotch Grove formations (Text-fig. 5) and (Witzke, 198la). These units all were deposited in open marine conditions in subtidal environments and are associated with skeletal wackestone and packstone fabrics. The relationship between the limestone units of the LaPorte City and the dolostone facies of the Hopkinton and Scotch Grove have been described as resulting from diage- netic alteration. With subaerial exposure of the basin margins, an early influx of meteoric phreatic water dis- placed original marine pore fluids to prevent pervasive dolomitization of the LaPorte City Formation (Witzke, 1981b; Ludvigson ef al., 1992). The Scotch Grove Formation is divided -into the Johns Creek Quarry, Welton, Buck Creek Quarry, Waubeek and Palisades-Kepler members (Text-figs. 4 and 5). The Johns Creek Quarry Member is a thin (O.5—5.5 meters) dolomitic unit that includes thicker (5-15 meters) mound facies at the base of the Scotch Grove. The Johns Creek Quarry is overlain by fossil- iferous dolostones of the Welton Member (12.5—75 meters) in the east and chert-rich dolostones of the Buck Creek Quarry Member (1-52 meters) in the west. There is also a facies relationship between the Palisades-Kepler Member (9—60 meters) that is com- prised of carbonate mound complexes and skeletal fa- cies that were shed from these “reefs” and the inter- mound facies of the Waubeek Member (12—17 meters). The Scotch Grove interval is associated with a ma- jor transgressive-regressive event at its base (Text-fig. 4) and a second, lesser transgressive-regressive cycle in the upper Scotch Grove concurrent with deposition of the Waubeek and Palisades-Kepler members. The overlying Gower Formation is associated with depo- sition of laminated subtidal carbonates which formed during a mid-Wenlock regression. BIOSTRATIGRAPHY The Hopkinton Formation which underlies the Scotch Grove/LaPorte City formations in the study area has been assigned a Llandovery age (mid- to late Aeronian through early to mid-Telychian) based on oc- currence of pentamerid and _ stricklandid brachiopod faunas (Witzke, 1992). The low diversity conodont faunas in this study (Text-figs. 6 and 7) tend to be dominated by Panderodus. The Scotch Grove—LaPorte City formations span a range from Llandovery (early to mid-Telychian) through early Wenlock (mid- to late Sheinwoodian). The overlying Gower Formation does not contain biostratigraphically diagnostic faunas and has been suggested to have an age of mid-Wenlock at its base and ranging up to late Wenlock-Ludlow age at its top based on brachiopod faunas (Witzke, 1992). Faunas in the basal LaPorte City Formation are as- signed to the eopennatus Zone of Mannik (1998) based on the occurrence of Aulacognathus bullatus and A. kuehni in the Garrison Core (GR) in a sample that also contains elements of Ozarkodina polinclinata polinclinata. Samples from the lower LaPorte City from the Highway 13 outcrop (H13) and Bailey’s Ford (BF) are assigned to the eopennatus Zone on the oc- currence of Pterospathodus eopennatus. Both faunas also include elements of Ozarkodina polinclinata po- linclinata. The lower Scotch Grove—LaPorte City at the Delhi (DLH) outcrop contain faunas assigned to the eopennatus Zone based on occurrence of Apsidog- nathus tuberculatus and Pterospathodus eopennatus. This interval also contains Ozarkodina polinclinata 96 BULLETIN 369 Subcommision on Silurian Stratigraphy (1995) P._ amorphognathoides z é zl : = 77 SILURIAN Aeronian ; i i i P. tenuis- D_ staurognathoides Jeppsson Not Zoned O. bohemica Onsagitia\sagitia Ko. ortus Superzone Upper K. wallisen Superzone ncartonensis-belophorus ©. sagitta rhenana- K. patula [O. sagitta rhenana Superzone K_ ranuliformis Interval Zone K. ranuliformis Superzone Lower K_ranulitormis Ps P. procerus Superzone no precise graptolite data Ps. Bicornis Superzone P_ a. amorphognathoides P. amorphognathoides Loydell et al. 1998 lowa Stratigraphy Gower conodonts not yet studied in detail Formation Scotch Grove - LaPorte City P. celloni formations Hopkinton Formation Text-figure 3.—Selected zonations for the late Llandovery and Wenlock with comparison to Iowa formations. polinclinata, Kockelella cf. K. abruptus and Disto- modus staurognathoides. The Delhi section includes a transition from the dolostone Scotch Grove Formation into the limestone LaPorte City Formation without no- ticeable changes in conodont faunas. The sample at DLH 6 contains platform (Pa) elements of both P. eopennatus and P. amorphognathoides angulatus re- sulting in assignment of a celloni Zone age as rede- fined by Mannik (1998), for the middle portion of the Delhi section. The co-occurrence of these two taxa may be a result of the sample interval or slightly dif- ferent ranges in the mid-continent of North America in comparison with Estonia. The occurrence of Ozar- kodina polinclinata polinclinata raises questions based on its occurrence with elements from distinctly eopen- natus and celloni zone faunas. Mannik (1992) identi- fied two subspecies of Ozarkodina polinclinata: Ozar- kodina polinclinata estonica that is restricted to the celloni zone and the nominal subspecies that is re- stricted to the amorphognathoides Zone. Only the nominal species is identified in these faunas, and it occurs at a significantly lower biostratigraphic level than that reported by Miannik (1992) in Estonia. The recovery of Pterospathodus amorphognathoides amorphognathoides from the middle Scotch Grove at the Hanken Quarry (HNQ) indicates that at least part of the formation correlates with the amorphognathoti- des Zone. The Welton Member at the Baldwin North (BN) section contains Ozarkodina excavata excavata which can be assigned a Wenlock to Ludlow age (Lower K. ranuliformis Zone) of Jeppsson (1997). Samples from the Waubeek Member (upper Scotch Grove Formation) at the Freeman Quarry (FMQ) are placed in the Ozarkodina sagitta rhenana Superzone of Jeppsson (1997) based on the occurrence of the nominal subspecies. The limited faunas that have been recovered from the Scotch Grove—LaPorte City interval allow initial assessment of ages for these units. It is also noted that the Llandovery-Wenlock boundary falls within the middle to upper portion of this sequence. The bound- ary occurs somewhere below the base of the Waubeek and Palisades-Kepler and in the middle of the Welton members of the Scotch Grove Formation. SYSTEMATIC PALEONTOLOGY The suprageneric classification in this report follows that of Sweet (1988). Illustrated specimens are housed ScoTCcH GROVE—LAPORTE CITY CONODONTS: METZGER 97 wn n RELATIVE SEA-LEVEL CURVE a Ore increasing depth ————————_> = re 3 ze ad a SAN imimeeesealete aos Se Sin & Wapsipinicon Gp =F = y a a V/ V/ o aa V/ = jt I osc we io) 7 i \ eo Sllree ! r 33 ° Ab fat O|-| € # ‘ : oe Ge) ° bad ledge a? - 2 o 3: y Vj - mounding és ye | | 3s >| \S* V/; _ mounding (S) > (Od, ies ol 5 ie} x] 3 = -O Ss ' se Ble l S§ O]s ' wo O a £&E n : ge Mons Cr Ol— 57 a eS ees fe Zz inure a ae om Glock il| iia pea z Farmers (aaa a k Creek a [Marcus PoP P i approx. ——< 1 thickness ©} sweeney AZ Lea ES B m ft a Pe ee 5075 BLAND- 2 150 NG _ 5 id =a | 100 SES a0 € 35 -~°%X a sl) oA 4 MOSALEM — 2 L Goo 50 FM. » & EL, oS E oo x (Se a= ° ] 85 ees o- ie) 50 a) ord Oo — dolomite (dolostone) A= laminated KEY “ brachiopod Seay brecciated p pentamerid brachiopod tabulate coral — dolomitic limestone Vv chert or residuum ; . e - S _. stricklandiid brachiopod i ©.o_. skeletal-moldic rock : (-\ _ stromatoporoid on limestone OnO 2 solitary rugose coral < — — argillaceous Text-figure 4.—Stratigraphic relationship between formations and members for the Iowa Silurian compared to relative sea-level curve (adapted from Witzke, 1992). 98 BULLETIN 369 Palisad . ft om ~P Kepler Mor M 1004-30 as OF j Ole pies br 20 50 Buck Creek 4 10 P Quarry Mor. 4 P o-to OaTul P 7 uorry Mbr. o MARCU A aPal me a Marcus Mbp 5 P N ETE | GR ie | SS MORTS Fm A [Benton Co ‘inn Co. Text-figure 5.—Stratigraphic cross-section of Silurian units in east-central lowa. Control points include both core and outcrop sections. Datum shifts from base of Devonian in the west to base of Scotch Grove Formation in the east (adapted from Witzke, 1992). For lithologic symbols, see Text-figure 4. FORMATION SCOTCH GROVE / LAPORTE CITY: SAMPLE | DLH] DLH] DLH] DLH] DLH] DLH NUMBER 2 3 SAMPLE WEIGHT (in kilograms) Panderodus sp 2 é 9 Apsidognathus tuberculatus Ozarkodina polinclinata polinchinata Pterospathodus sp Pterospathodus eopennatus Kockelella cf. K. abruptus Distomodus staurognathoides P. amorphognathoides angulatus Oulodus sp Indeterminate Platform Element Indeterminate Ramiform Element Text-figure 6.—Conodont distribution within the Scotch Grove/LaPorte City formations at the Delhi West section (DLH). See Text-figure 2 and appendix for sample levels. SCOTCH GROVE—LAPORTE CITY CONODONTS: METZGER 99 FORMATION SCOTCH SAMPLE GR | GR} GR} GR NUMBER 437 | 408 | 404 | 392.5 Panderodus sp | 124[ 9 | 1 4 10 fr 7 GROVE / LAPORTE GR | GR | GR|H13} BF | JCQ 384 -6| 362| 1 1 2 ASST Aulacognathus bullatus Aulacoynathus? bullatus Aulacoynathus kuehni Oz. polinclinata polinclinata Oulodus sp. Pseudooneotodus bicomis P. a. amorphognathoides Pterospathodus eopennatus Icriodella sp. Ozarkodina excavata excavata Kockelella sp. Ozarkodina sagitta rhenana Sa Kockelella ranuliformis Pal | Indeterminate Platform Element Indeterminate Ramiform Element zee Se a Text-figure 7—Conodont distribution within the Scotch Grove/LaPorte City and Gower formations at GR (Garrison Core), H13 (Highway 13), BF (Bailey’s Ford), JCQ (Johns Creek Quarry), BN (North Baldwin), HNQ (Hanken Quarry), WBK (Waubeek), FMQ (Freeman Quarry also known as Pleasant Hill Quarry), and BSQ (Beuse Quarry). See Text-figure 2 and appendix for sample levels. in The University of lowa Paleontology Repository (SUI). Phylum CONODONTA Pander, 1856 Class CONODONTI Branson, 1938 Order OZARKODINIDA Dzik, 1976 Family SPATHOGNATHODONTIDAE Hass, 1959 Genus OZARKODINA Branson and Mehl, 1933 Type species.—Ozarkodina confluens (Branson and Mehl, 1933) [=Ozarkodina typica Branson and Mehl, 1933]. Ozarkodina polinclinata polinclinata (Nicoll and Rexroad, 1969) Plate 1, figures 24—26 Spathognathodus polinclinatus Nicoll and Rexroad, 1969, p. 60, pl. 2, fig. 19; 20: Ozarkodina polinclinata (Nicoll and Rexroad) Klapper in Ziegler, 1977, p. 57-58, Ozarkodina pl. 3, figs. 5, 6; Kleffner, 1987, p. 87, fig. 5, PM 17-22. Ozarkodina polinclinata polinclinata (Nicoll and Rexroad). Mannik, 1992, p. 56-58, fig. 4, 1-28, fig. 5, 1-7, plate figs. 8, 10—20 (see synonymy). Discussion.—The most abundant platform taxa in these collections, representative elements from the en- tire apparatus as reconstructed by Cooper (1977), Kleffner (1987) and Mannik (1992) are present. The Pa element conforms to the description of the nominal subspecies of Mannik (1992) by exhibiting less fused denticles and a well-developed posteriorly inclined cusp. Collections.—14 and 2 questionable Pa elements, 10 and 2 questionable Pb elements, 15 and 2 questionable M elements, 11 Sa elements, 12 and | questionable Sb element, 39 and 1 questionable Sc element from the 369 Z cal *, N 4 - ““Htgeeeens<#O??™ eT | , wo ScoTcH GROVE—LAPoRTE CIty CONODONTS: METZGER 101 11-14. PLATE | . Walliserodus sp. 1. Coniform element, lateral view. GR-444. SUI 94708. . Pseudooneotodus bicornis Drygant, 1974 2. Conical element, upper oblique view. BSQ-bb. SUI 94709. 3. Conical element, upper oblique view. BSQ-bb. SUI 94710. 4. Conical element, upper oblique view. DLH-6. SUI 94711. . Pterospathodus eopennatus ssp. nov. 2 morphotype 4 Mannik, 1998 5. Pa element, lateral view. H13-1. SUI 94712. 6. Pa element, upper view. H13-1. SUI 94712. . Ozarkodina excavata excavata? (Branson and Mehl, 1933) 7. M element, inner lateral view. WBK-5E SUI 94713. . Pterospathodus amorphognathoides angulatus (Walliser, 1964) 8. Pb element, inner lateral view. DLH-6. SUI 94714. 16. Pa element, upper view. DLH-6. SUI 94721. 17. Pa element, upper view. DLH-6. SUI 94722. . Ozarkodina excavata excavata (Branson and Mehl, 1933) 9. Pb element, inner lateral view. BN-4. SUI 94715. 10. Pa element, lateral view. BN-4. SUI 94716. Ozarkodina sagitta rhenana (Walliser, 1964) 11. Pa element, upper view. FMQ-top. SUI 94717. 12. Pa element, lateral view. FMQ-top. SUI 94717. 13. Sb element, inner lateral view. FMQ-top. SUI 94718. 14. Sa element, inner lateral view. FMQ-top. SUI 94719. . Kockelella? sp. 15. Sa element, inner lateral view. WBK-5F SUI 94720. . Kockelella cf. K. abruptus (Aldridge, 1972) 18. Pa element, upper view. DLH-4. SUI 94723. 19. Pa element, lateral view. DLH-4. SUI 94723. 20. Pa element, upper view. DLH-8. SUI 94724. . Aulacognathus? bullatus (Nicoll and Rexroad, 1969) 21. Pa element, upper view. GR-444. SUI 94725. 22. Pa element, lower view. GR-444. SUI 94725. . Aulacognathus kuehni Mostler, 1967 23. Pa element, upper view. GR-444. SUI 94726. . Ozarkodina polinclinata polinclinata (Nicoll and Rexroad, 1969) 24. Pa element, inner lateral view. DLH-7. SUI 94727. 25. Pb element, inner lateral view. DLH-5. SUI 94728. 26. Sc element, inner lateral view. DLH-3. SUI 94729. 27. Apsidognathus tuberculatus Walliser, 1964 27. Pa element, upper view. DLH-1. SUI 94730. 28. Kockelella ranuliformis (Walliser, 1964) 2934, 35: 28. Pa element, upper view. FMQ-3. SUI 94731. Aulacognathus bullatus (Nicoll and Rexroad, 1969) 29. Sa element, inner lateral view. GR-444. SUI 94732. 34. Pb element, inner lateral view. GR-444. SUI 94736. 35. Pa element, upper view. GR-444. SUI 94737. . Distomodus staurognathoides (Walliser, 1964) 30. Pa element, upper view. GR-392.5. SUI 94733. . Pterospathodus amorphognathoides amorphognathoides Walliser, 1964 31. Pa element, upper view. IS-1. SUI 94734. 32. Pb element, inner lateral view. IS-1. SUI 94735. 33. Pb element, upper view. IS-1. SUI 94735. Magnifications all 40. 102 BULLETIN 369 Delhi West (DLH), Garrison Core (GR), Highway 13 road cut (H13), Bailey’s Ford (BF) and John’s Creek Quarry (JCQ). Family KOCKELELLIDAE Klapper in Clark et al., 1981 Genus KOCKELELLA Walliser, 1957 Type species.—Kockelella variabilis Walliser, 1957. Kockelella cf. K. abruptus (Aldridge, 1972) Plate 1, figures 18—20 Spathognathodus cf. S. abruptus Aldridge, 1972, p. 212, pl. 4, fig. 8. Discussion.—Specimens in this study are similar to the specimen illustrated as Spathognathodus cf. S. abruptus by Aldridge (1972). Specimens may be an- cestral to Kockelella ranuliformis, only lacking devel- opment of large basal cavity. Collections. —2 Pa elements from the Delhi West section. Family PTEROSPATHODONTIDAE Cooper, 1977 Genus PTEROSPATHODUS Walliser, 1964 Type species.—Pterospathodus amorphognathoides Walliser, 1964. Pterospathodus amorphognathoides angulatus (Walliser, 1964) Plate 1, figures 8, 16, 17 Spathognathodus pennatus angulatus Walliser, 1964, p. 79, pl. 14, figs. 19-22. Pterospathodus amorphognathoides angulatus (Walliser). Ménnik 1998, p. 1015-1019, pl. 2, figs. 1-22, 24-31, text-figs. 7-8 (see synonymy). Discussion.—With revision of the Pterospathodus lineage, Mannik (1998) identified P. amorphognathoi- des angulatus as the initial member of the P. amor- phognathoides lineage. Specimens in this study exhibit a long blade with platform containing approximately 20 denticles. Specimens in this study are most similar to the Mannik (1998) morphotype with tall denticles. Collections.—S Pa elements, 3 questionably as- signed Pa elements, | Pb element and 3 questionably assigned Pb elements, all from the Delhi West section. Pterospathodus eopennatus Mannik, 1998 Plate 1, figures 5, 6 Pterospathodus eopennatus Mannik, 1998, p. 1007-1013, pl. 1, figs. 1-46, pl. 2, figs. 23, 32—41, text-figs. 4-6 (see synonymy). Discussion.—Specimens in this study are most closely related to Prerospathodus eopennatus ssp. nov. 2 morphotype 4 of Mannik (1998, pl. 2, figs. 33, 38, 41; text-fig. 6, L, O-P, U). The most characteristic fea- ture of this morphotype is a sharp decrease in denticle height just behind the cusp and posterior denticles be- ing considerably shorter. The short, almost triangular, Pb element associated with P. eopennatus is also pres- ent in these faunas. Collections. —6 Pa elements, 13 and | questionably assigned Pb element, 2 M elements and 8 symmetry elements from Delhi West, H13, and Bailey’s Ford. CONCLUSIONS Conodont faunas in this study allow assignment of the LaPorte City/Scotch Grove formations to an inter- val correlative to the eopennatus Zone through Ozar- kodina sagitta rhenana Superzone of the Silurian stan- dard conodont zonation (Text-fig. 3). There is a com- plicated stratigraphic relationship between the units in this study, due both to initial facies relationships be- tween members of the Scotch Grove Formation, and due to diagenetic alteration of the Scotch Grove com- pared to the limestones of the LaPorte City Formation. The conodont faunas are sparse in both lithologies. The presence of biostratigraphically diagnostic taxa gives some promise to more intensive study of this interval in the future, although this will involve the utilization of large sample sizes to get sufficient co- nodont faunas. REFERENCES CITED Aldridge, R.J. 1972. Llandovery conodonts from the Welsh Borderland. Bul- letin of the British Museum (Natural History), Geology, vol. 22, pp. 127-231. Branson, E.B. 1938. Stratigraphy and paleontology of the Lower Mississippian of Missouri. Part I. The University of Missouri Studies, vol. 13, no. 3, 208 pp. Branson, E.B., and Mehl, M.G. 1933. Conodonts from the Bainbridge (Silurian) of Missouri. University of Missouri Studies, vol. 8, pp. 39-52, pl. 3. Calvin, S. 1896. Geology of Jones County. lowa Geological Survey, An- nual Report, vol. 8, pp. 121-192. Clark, D.L., Sweet, W.C., Bergstrom, S.M., Klapper, G., Austin, R.L., Rhodes, F.H.T., Miller, K.J., Ziegler, W., Lind- strom, M., Miller, J.F., and Harris, A.G. 1981. Conodonta. in Treatise on invertebrate paleontology, Part W, Miscellanea, Supplement 2. R.A. Robison, ed., Geo- logical Society of America and the University of Kansas Press, Lawrence, 202 p. ScotcH GROVE—LAPORTE CITY CONODONTS: METZGER 103 Cooper, B.J. 1977. Toward a familial classification of Silurian conodonts. Journal of Paleontology, vol. 51, pp. 1057-1071. Drygant, D.M. 1974. Simple cones from the Silurian and lowermost Devonian of the Volyno-Podolian area. Paleontologicheskiy Sbor- nik, vol. 10, pp. 64-70. Dzik, J. 1976. Remarks on the evolution of Ordovician conodonts. Acta Palaeontologica Polonica, vol. 21, pp. 395-455. Hall, J., and Whitney, J.D. 1858. Report on the Geological Survey of the State of Iowa: Iowa State Legislature, vol. 1, 472 pp. Hass, W.H. 1959. Conodonts from the Chappel Limestone of Texas. United States Geological Survey Professional Paper 294J, pp. 365-400. Jeppsson, L. 1997. A new latest Telychian, Sheinwoodian and Early Hom- erian (Early Silurian) standard conodont zonation. Trans- actions of the Royal Society of Edinburgh: Earth Scienc- es, vol. 88, pp. 91-114. Johnson, M.E. 1975. Recurrent community patterns in epeiric seas: the Lower Silurian of eastern Iowa. Proceedings of the lowa Acad- emy of Science, vol. 82, pp. 130-139. 1977. Community succession and replacement in Early Silurian platform seas: the Llandovery Series of eastern Iowa. Un- published Ph.D. thesis, University of Chicago, 237 pp. 1979. Evolutionary brachiopod lineages from the Llandovery Series of eastern Iowa. Palaeontology, vol. 22, pp. 549— 567. Kleffner, M.A. 1987. Conodonts of the Estill Shale and Bisher Formation (Si- lurian, southern Ohio): biostratigraphy and distribution. Ohio Journal of Science, vol. 87, pp. 78-89. 1990. Wenlockian (Silurian) conodont biostratigraphy, deposi- tional environments, and depositional history along the eastern flank of the Cincinnati Arch in southern Ohio. Journal of Paleontology, vol. 64, pp. 319-328. 1991. Conodont biostratigraphy of the upper part of the Clinton Group and the Lockport Group (Silurian) in the Niagara Gorge region, New York and Ontario. Journal of Pale- ontology, vol. 65, pp. 500-511. 1994. Conodont biostratigraphy and depositional history of stra- ta comprising the Niagaran sequence (Silurian) in the northern part of the Cincinnati Arch region, west-central Ohio, and evolution of Kockelella walliseri (Helfrich). Journal of Paleontology, vol. 68, pp. 141-153. Loydell, D.K., Kaljo, D., and Mannik, P. 1998. Integrated biostratigraphy of the lower Silurian of the Ohesaare core, Saaremaa, Estonia. Geological Magazine, vol. 135, pp. 769-783. Ludvigson, G.A., Witzke, B.J., and Gonzalez, L.A. 1992. Observations on the diagenesis and stable isotopic com- positions of Silurian carbonates in Iowa. in: Silurian Stra- tigraphy and carbonate mound facies of eastern Iowa: Field trip guidebook to Silurian exposures in Jones and Linn Counties. lowa Department of Natural Resources, Guidebook Series No. 11, pp. 73-83. Mannik, P. 1992. Taxonomy of the conodont species Ozarkodina polincli- nata (Nicoll and Rexroad) in the Silurian of Estonia. Pro- ceedings of the Estonian Academy of Science, Geology, vol. 41, pp. 54—62. 1998. Evolution and taxonomy of the Silurian conodont Prer- ospathodus. Palaeontology, vol. 41, pp. 1001-1050. Mostler, H.L. 1967. Conodonten aus dem tieferen Silur der Kitzbiihler Alpen (Tirol). Annalen des Naturhistorischen Museums in Wien, vol. 71, pp. 295-303. Nicoll, R.S., and Rexroad, C.B. 1969. Stratigraphy and conodont paleontology of the Salamonie Dolomite and Lee Creek Member of the Brassfield Lime- stone (Silurian) in southeastern Indiana and adjacent Ken- tucky. Indiana Geological Survey Bulletin 40, 73 p. Pander, C.H. 1856. Monographie der fossilen Fische des silurischen Systems der russich-baltischen Gouvernements. Akademie der Wissenschaften, St. Petersburg, 91 p. Shaver, R.H., Ault, C.H., Ausich, W.I., Droste, J.B., Horowitz, A.S., James, W.C., Okla, S.M., Rexroad, C.B., Sucho- mel, D.M., and Welch, J.R. 1978. The search for a Silurian reef model, Great Lakes area. Indiana Department of Natural Resources, Geological Survey, Special Report 15, 36 pp. Sweet, W.C. 1988. The Conodonta: morphology, taxonomy, paleoecology, and evolutionary history of a long-extinct animal phylum. Ox- ford Monographs on Geology and Geophysics, 10, 212 p. Walliser, O.H. 1957. Conodonten aus dem oberen Gotlandium Deutschlands und der Karnischen Alpen. Hessisches Landesamtes fiir Bodenforschung Notizblatt, vol. 85, pp. 28-52. 1964. Conodonten des Silurs. Abhandlungen des Hessischen Landesamtes fiir Bodenforschung, 41, 106 p. Witzke, B.J. 1976. Echinoderms of the Hopkinton Dolomite (Lower Siluri- an), eastern Iowa. Unpublished M.S. thesis, University of Iowa, 224 pp. 1981la. Stratigraphy, depositional environments, and diagenesis of the eastern Iowa Silurian sequence. Unpublished Ph.D. thesis, University of lowa, 574 pp. 1981b. Silurian stratigraphy of eastern Linn and western Jones counties, Iowa. Geological Society of Iowa, Guidebook 35, 38 pp. 1983. 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Schweizerbart’sche Ver- lagsbuchhandlung, Stuttgart, 574 p. 104 BULLETIN 369 APPENDIX COLLECTING LOCALITIES AND SAMPLE INTERVALS Abbreviations used for stratigraphic units: Maq (Maquoketa Formation), Bl (Blanding Formation), Hop (Hopkinton Formation), SG (Scotch Grove For- mation), LPC (LaPorte City Formation), Gwr (Gower Formation), Wap (Wapsipinicon Group); BCQ (Buck Creek Quarry Member), WL (Welton Member), FC (Farmers Creek Member), PR (Picture Rock Member), JCQ (Johns Creek Quarry Member), Wbk (Waubeek Member), An-LC (Anamosa-LeClaire members undif- ferentiated). BF: BN: BSQ: DEH: Baileys Ford, Logan Quarry, Kuhlman Con- struction Co., SE sec. 9, T 88 N, R 5 W, Del- aware County; sample BF-1 taken 50 cm above base of LaPorte City Fm.; Hop (FC, PR), LPC. Ref: unpublished DOT log. Baldwin North, roadcuts and bluff exposures along Maquoketa River, NE sec. 3, T 84 N,R 1 E, Jackson County; sample BN-4 from 1.5 meters above the Callipentamerus-bearing bed in the succession; Hop (FC, PR), SG (WL). Refs: Witzke (1976, 1981a), Johnson (1977). Beuse Quarry, old quarry workings, NE SW NW sec. 28, T 80 N, R 5 E, Scott County; sample BSQ-bb from 1.2 meters above the base of quarry section; Gwr (An-LC). Ref: Witzke (198 la). Delhi West Roadcut, SW SW SW SW sec. 18, T 88 N, R 4 W, Delaware Co.; Sample intervals from the base of outcrop in meters are: DLH- 1, 1.50-1.75; DLH-2, 2.47-2.57; DLH-3, 2.67—2.82; DLH-4, 3.30—3.37; DLH-5, 3.71- 3.76; DLH-6, 3.86—-3.98; DLH-7, 4.43—4.48; FMQ: GR: HNQ: ICQ: WBK: DLH-8, 5.23-5.38; DLH-9, 5.63—5.68; DLH- 10, 6.41-6.50; DLH-11, 7.07—7.17; DLH-12, 7.72—7.82; DLH-13, 7.97—8.02; SG, (BCQ), BRE: Freeman Quarry, old quarry bordering Plum River Fault Zone, NE SE SW sec. 20, T 83 N, R 2 W, Jones County; sample FMQ-3 is from 75 cm below top of quarry, sample FMQ-top is the uppermost bed exposed at the quarry: SG (Wbk). Ref: Witzke (198 1a). Garrison core, Carbonate Hydrology Project, SW NW SW SW sec. 33; 1 85 N) RoliaW; Benton County; Sample intervals are indicated as depth in core (feet) in Text-figure 5; Maq, Bl, Hop, LPC, Wap. Ref: Witzke (1981la, p. 504-506). Hanken Quarry, abandoned, NW NW NE sec. 6, T 85 N, R 2 W, Jones County; sample IS-1 is from the upper | meter in the quarry; adja- cent geest localities (fields and ravines), SW NE and NE NE sec. 6; SG (BCQ). Refs: Calvin (1896), Johnson (1977), Witzke (1976, 198 1a, 1992). Johns Creek Quarry, Kuhlman Construction Co., type locality of Johns Creek Quarry Mem- ber, c E % SW sec. 36, T 88 IN; R 2 W, Du= buque County; sample JCQ-2 from lower Scotch Grove Fm.; Hop (FC, PR), SG GCQ; WL, BCQ geest). Refs: Johnson (1975, 1977, p. 140), Witzke (1976), Shaver et al. (1978). Waubeek exposures, roadcuts and bluffs along Wapsipinicon River upstream from Waubeek, type locality for Waubeek Member, NE sec. 17, T 85 N, R5 W, Linn County; sample WBK-5f is from the top of the exposure. Refs: Witzke (1981la, 1981b). SILURIAN-DEVONIAN BOUNDARY, WEST TEXAS: BARRICK ef al. 105 THE SILURIAN-DEVONIAN BOUNDARY AND THE KLONK EVENT IN THE FRAME FORMATION, SUBSURFACE WEST TEXAS JAMES E. BARRICK Department of Geosciences Texas Tech University Lubbock, Texas 79409, U. S. A. BEVERLY D. MEYER Oklahoma Panhandle State University Goodwell, Oklahoma 73937, U.S. A. STEPHEN C. RUPPEL Bureau of Economic Geology John A. and Katherine G. Jackson School of Geosciences University of Texas at Austin, Austin, Texas 78713, U.S. A. ABSTRACT The Frame Formation (Wristen Group) in southern Andrews County, Texas, comprises fine-grained carbonate slope deposits that span the Silurian-Devonian boundary. Conodont faunas from a core of the upper Frame in the Amoco Three Bar 74 well range in age from Pridoli (detorta Zone) into the middle Lochkovian (omoalpha Zone). The Klonk event of Jeppsson (1998) may be represented by an extinction or replacement event in the Frame Formation, as well as in equivalent shelf strata in southern Oklahoma, where diagnostic late Silurian conodont species, mostly coniform taxa, are abruptly replaced by characteristic Early Devonian species. This event precedes the appearance of /criodus postwoschmidti and may coincide with the Silurian-Devonian boundary. INTRODUCTION The Silurian-Devonian stratigraphic section in the Permian Basin region of West Texas and eastern New Mexico comprises over 2500 feet (760 m) of carbon- ates and shales that include prolific reservoirs and source rocks for hydrocarbons. Despite their economic importance, the time relations of the complex series of intergrading lithofacies that constitute this section are poorly known. The main reason for the paucity of chronostratigraphic control is the rarity of well cores from which well-constrained biostratigraphic data can be obtained. Previous works utilizing shelly fossils (Wilson and Majewski, 1960) and graptolites (Decker, 1942, 1952) have placed these strata in a general time frame (COSUNA Project, Hills and Kottlowski, 1983). More recent research on conodont faunas has begun to clarify the ages of some Silurian and Devonian units (Barrick and others, 1993; Barrick, 1995; Meyer and Barrick, 2000; Meyer, 2002), but details of the place- ment of major chronostratigraphic boundaries, in par- ticular the Silurian-Devonian boundary, have remained unclear. Recent studies of depositional and diagenetic facies in Silurian and Devonian rocks in the Permian Basin region have developed a new understanding of the spa- tial distribution of major lithofacies units in the car- bonate-dominated Silurian to Lower Devonian section and an improved reconstruction of the depositional history (Ruppel, 1993; Ruppel and Holtz, 1994; Rup- pel and Hovorka, 1995; Ruppel and Barnaby, 2001). As part of a program to characterize hydrocarbons res- ervoirs on lands owned by the University of Texas, cores from the Three Bar Field in southern Andrews County, Texas (Text-fig. 1), which produces from the Lower Devonian Thirtyone Formation, were made available for study (Ruppel and Hovorka, 1995). In the course of this research, a core that includes over 150 feet (46 m) of the underlying Frame Formation was obtained and has been processed for conodonts. Data 106 BULLETIN 369 DAWSON GAINES Faskin platformjdeposits UPTON REAGAN Text-figure. 1—Locality map showing location of the Amoco Three Bar 74 well in West Texas. Position of the edge of the Wristen (Fasken) platform margin from Ruppel and Holtz (1994, fig. 5) ANDREWS AMOCO 3-BAR 74 slope deposits ECTOR 30 miles ee 0 40 km from this core permit resolution of the placement of the Silurian-Devonian boundary in this region as well as information on the significant changes in conodont faunas that occur during the “‘Klonk event’’ of Jepps- son (1998). ACKNOWLEDGMENTS The authors wish to thank Dr. Michael A. Murphy (Univ. of California-Davis) for his careful and con- structive review of the manuscript. Access to the Amo- co Production Company Three Bar 74 core was made possible by a core donation to the Texas Bureau of Economic Geology by Altura Energy (now part of Oc- cidental Petroleum). STRATIGRAPHIC SETTING Ruppel and Holtz (1994) outlined the overall geo- logical setting and depositional history of upper Silu- rian and Lower Devonian strata in the Permian Basin region (Text-fig. 2). During the Wenlock, tectonic sub- sidence transformed the Llandovery carbonate plat- form (Fusselman Formation) into a ramp that deep- ened to the south. In the outer ramp setting, nodular carbonate wackestones of the Wink Formation are overlain by the more distal, deeper water carbonates and shales of the Frame Formation. Continued subsi- dence during the late Silurian produced a deeper water basin to the present-day south, which was flanked on the north by shelf platform to steep ramp that sloped into the basin. Aggradation of the platform in central yovem ences Subsurface Wa $a (part) MMMM sig VLLLLLLLLL 2 MISS N THIRTYONE FORMATION ? Lower DEVONIAN x a (a) [ov = |FASKEN|FRAME [a oO ra 2 Ludlow - < oe > = = WINK | al Tape | satiele. FORMATION SFL ILL ELL SLES AN ON very SISISIIILLS MONTOYA FORMATION FUSSELM FORMATI [= ne) aa = Text-figure. 2.—Stratigraphic column of latest Ordovician (ORD.) through Devonian strata in the subsurface of West Texas. Ages of strata based largely on conodont faunas discussed in Barrick (1995), Meyer and Barrick (2000) and Meyer (2002). MISS. = Mississip- pian. Andrews County, Texas, and northward, as represented by the Fasken Formation produced a shelf margin in central Andrews County, from which skeletal debris was delivered by downslope transport into the Frame basin. Facies and geometries in the Fasken Formation show that the platform-margin buildups were primarily aggradational, and that relatively little progradation of the shelf margin occurred during the late Silurian and Early Devonian. The Wink Formation and possibly the lower part of SILURIAN-DEVONIAN BOUNDARY, WEST TEXAS: BARRICK et al. 107 the Fasken Formation are Wenlock in age (Barrick, 1995), but the ages of the Frame Formation in the basin and the upper part of the Fasken Formation on the shelf are poorly known. Sparse Ludlow to Pridoli conodont faunas have been reported from dolostones assigned to the Fasken Formation well north of the basin margin (Barrick, 1995), but no Devonian taxa have been recovered from beds assigned to the Fasken. No evidence of breaks in deposition and related dia- genetic alteration have been reported from the Fasken, and deposition appears to have continued without sig- nificant interruption from the Silurian into the Early Devonian on the platform. Decker (1942, 1952) described Silurian graptolites from dark shales that we assign to the Frame Forma- tion from two wells in Crane County, Texas (Text-fig. 1). Finney (in Barrick et al., 1993) restudied Decker’s collections and reported that the graptolites ranged in age from late Silurian (no older than Ludlow) to as young as the Early Devonian (Pragian). Fragments of Icriodus Pa elements were obtained from dark shales of the Frame just above the Wink Formation in the Pegasus core in Midland County, Texas (Barrick ef al., 1993). These biostratigraphic data suggest that depo- sition of dark shales and carbonates of the Frame con- tinued from the Ludlow into the Early Devonian and that the Silurian/Devonian boundary should le within the Frame Formation in the basin. Ruppel and Holtz (1994) indicated that a major rise in sea level took place in West Texas and eastern New Mexico during the Early Devonian, which is reflected in the distinctly deeper water character of the basal deposits of the Thirtyone Formation, especially on the shelf margin area in Andrews County. There, deeper water Thirtyone chert deposits overlie Fasken reef de- posits (EK J. Lucia, cited in Ruppel and Holtz, 1994). The Thirtyone Formation represents a thick wedge of cherts and siliceous carbonates that prograded south- ward into the basin during the Early Devonian (Ruppel and Holtz, 1994). The timing of the filling of the Thir- tyone basin is unclear. Shelly faunas suggest that the unit was deposited during the Early to Middle Devo- nian (Wilson and Majewski, 1960), but conodont fau- nas indicate only a Pragian age for the unit (Barrick, 1995; Meyer, 2002). THE AMOCO THREE BAR 74 CORE In southern Andrews County (Text-fig. 1), the shelf facies of the Fasken shelf grade into the outer ramp to slope facies of the Frame Formation (Ruppel and Holtz, 1994, fig. 4). The Amoco Three Bar 74 well lies just south of the transition, where nearly 500 feet (152 m) of the Frame Formation is recorded by cut- tings and petrophysical logs. The base of the Thirtyone Formation is readily identified by its distinctive log signature (Ruppel and Holtz, 1994, fig. 10) at a depth of 8051 feet (2454 m) below sea level. Approximately 150 feet (45.7 m) of shale and carbonate assigned to the Frame Formation were cored in the Amoco Three Bar 74 (Text-fig. 3). The top of the core lies at 8112 feet (2472.5 m), 61 feet (18.6 m) below the top of the Frame, and extends down to 8258 feet (2517 m), near- ly 300 feet (91.4 m) above of the base of the forma- tion. The lithologic sequence of the cored interval is shown on Text-figure 3. In subsequent discussions, depth measurements are presented as feet below sea level, as this is the convention for subsurface work in the Permian Basin region of west Texas and eastern New Mexico. The lower portion of the cored interval (8258’ to 8196’) consists of argillaceous and silty, slightly do- lomitic carbonate mudstones and wackestones. Below 8235’ limestones are nodular bedded and interbedded with minor amounts of calcareous shale. From 8235’ to 8196’ the limestones are locally parallel-laminated or burrowed. At irregular intervals, angular clasts of skeletal to pelloidal carbonate mudstone occur. In con- trast to the matrix, the clasts appear to contain little terrigenous material. The clasts are most prominent in three intervals (8251.5'—8247'; 8224'-8221'; and 8206’—8200'), but clasts occur as thin layers or indi- vidually at other levels. The clasts appear to represent lithified carbonate material that was eroded off the shelf margin and carried deeper onto the slope region by downslope transport. Thin crinoid-brachiopod packstone/grainstone beds appear at 8196’ and occur up to 8178’. The poorly sorted, slightly abraded skeletal grains are dominated by echinoderm and brachiopod debris and include os- tracods, trilobite and bryozoan grains, as well as pel- loids. The grainstone beds are interbedded with the typical Frame carbonate mudstones and wackestones, and may represent skeletal sands derived from the shelf margin. Above 8178’, slightly dolomitic lami- nated carbonate mudstones, wackestones, and rare packstones constitute the Frame Formation. In the up- per parts of the core, brachiopods, corals, and bryo- zoans are more common, and the matrix becomes more argillaceous and silty. At 8116’, a few clasts of peloidal skeletal grainstone, like those found lower in the Frame, occur. Log responses indicate no significant additional change in lithology in the uppermost part of the Frame Formation in the Three Bar 74 well. The overall succession of facies in the Three Bar 74 core suggests only a possible slight shallowing upward pattern for the Frame Formation, probably moderated by sea-level fluctuations. This could be a result of moderate progradation of the shelf margin during the 108 BULLETIN 369 81 1 60 feet to Thirtyone aaa ee E el | 8120 g& . 3 ' Se ites 8130 & 1S ‘ls le 8140 a! o 3 a 8150 E | z|> 8 ig CI > = 8160 S s ro) 3 x~/O g}| & IS 3] 3 a 8 Ww 8170 el SIslQ 2] sg! § € rz) 8 —E i= a = £ Oo 8180 | 3 $ ® & is} 1] 4 8190 7) Q = “1 2 g 8200 Ss > 8210 2 g a ) 8220 a] §] s! | 8] 8 z s| g] s _|< a == a e Ps o|> = oc a 8240 ales 8 a.| = a 2 5 ” o| 3 s 6 sjé & 8250 Bl] s 8 B/ 8] 3 a = 8260 S16 al [| 300 feet to Wink Fm. arene ewcgilaceous hired as = [x] calcareous shale skeletal gralnstone Text-figure. 3.—Generalized lithologic column of the Frame For- mation in the Amoco Three Bar 74 core, Andrews County, Texas and ranges of important conodont species. Conodont zones and age assignments discussed in text. time the Frame was being deposited. However, it is unlikely that im situ shelf carbonates comprise any part of the Frame in this core, and we interpret the Frame here to represent a carbonate slope setting near the shelf margin. CONODONT FAUNA The core of the Frame Formation in the Amoco Three Bar 74 well was sampled for conodonts at one- foot (30 cm) and three-foot (90 cm) intervals. Previous handling of the core had obscured some footage in- dicators, which prevented sampling the entire core at one-foot intervals. Where the exact level in the core could be identified to the foot, a sample was taken and processed. Where the exact position of a core fragment was unclear, the material could be only be located within the three-foot interval given on the core box. In some instances, smaller one-foot samples and a larger sample including material from the three-foot interval were processed separately. As a result, nu- merous one-foot samples and fewer three-foot samples were processed. Ranges of significant conodont taxa are plotted on Text-figures 3 and 4. In only a few in- stances did the one-foot sampling reveal greater bio- stratigraphic resolution than the three-foot samples; these cases are noted below. Table 1 shows the number of conodonts recovered, recorded in three-foot inter- vals, and the relative abundance diagram (Text-fig. 5) is plotted at three-foot intervals. The presence of carbonate clasts and possibly skel- etal sands derived from an adjacent shelf margin sug- gests that minor admixing of conodont elements of different ages is possible. However, as the summary of faunas presented below indicates, we have not seen any evidence of conodonts of different zones occurring together. The carbonate material that was transported from the shelf setting into the slope environment of Frame deposition in the Three Bar 74 core must have been carried onto the slope soon after deposition, and in the case of the clasts, soon after early lithification. The lowest part of the core contains the typical late Silurian (Pridoli) fauna of Dvorakia amsdeni, Dapsi- lodus sp., Decoriconus fragilis, Belodella anfracta, and Panderodus sp. (Text-figs. 3 and 4; Table 1). Un- usual Pa elements that belong to an Ozarkodina ex- cavata-type apparatus occur as do a few Pa elements that are assigned to the O. remscheidensis group. Oul- odus elegans detorta, indicative of the latest Silurian detorta Zone, appears at 8252’. Ozarkodina? planilin- gua appears at 8233’ and ranges higher. Belodella coarctata appears and becomes relatively abundant at 8231’; this species is characteristic of the upper detorta Zone in the Henryhouse Formation in Oklahoma (Bar- SILURIAN-DEVONIAN BOUNDARY, WEST TEXAS: BARRICK et al. 109 nd Icriodus postwoschmiadti Oulodus cristagalli? 1 Pseudooneotodus acme Belodelia sp. cf. B. resima 8205 : i Decoriconus acme i Ozarkodina remscheidensis i Ozarkodina? planiligua Panderodus sp. Belodella sp. indet. Ozarkodina excavata Dapsilodus sp. Belodella coarctata Oulodus elegans detorta Icriodus sp indet. 8220 Text-figure. 4.—Detailed lithologic column and conodont ranges across the Silurian-Devonian boundary interval in the Amoco Three Bar 74 core, Andrews County, Texas. See text for details about faunal changes and placement of the systemic boundary. Lithologic symbols given on Text-figure 3. rick and Klapper, 1992). An indeterminate, juvenile Pa element of /criodus occurs at 8219’. The most dramatic shift in conodont faunas occurs from 8213’ to 8207’ (Text-fig. 5). The three most char- acteristic species of the upper detorta Zone, Belodella coarctata, Dapsilodus sp., and Panderodus sp. disap- pear at 8211’—8212’. Only a single specimen of Pan- derodus occurs higher in the core (8197’—8200'). The highest collection with Oulodus elegans detorta (8213’—8210') includes Sc elements with two small denticles between some of the large denticles. This subspecies may disappear at this level, or just higher (8209’—8210'), where a few poorly preserved rami- form elements occur. At 8213’ Dvorakia philipi? ap- pears and at 8207’ Belodella cf. B. resima appears and becomes abundant. The low abundance of the ancestral species, D. amsdeni and B. anfracta, and poor pres- ervation make the position of the faunal transitions in Dvorakia and Belodella difficult to locate exactly. Ozarkodina remscheidensis, which was uncommon in the underlying beds, becomes a persistent part of the fauna at 8213’ and Ozarkodina? planilingua occurs in small numbers. Decoriconus fragilis becomes more abundant than below, and Pseudooneotodus beckman- ni, Which occurred sparingly below, rises to moderate abundance at 8207’. Robust ramiform elements that may be referred questionably to Oulodus cristagalli? appear in small numbers at 8207’ and range higher. Although a few indeterminate Pa elements and con- iform elements of /criodus appear lower, the first iden- tifiable species is /. postwoschmidti, which appears with the first skeletal grainstone layer at 8195’. Ele- ments of Icriodus postwoschmidti are moderately com- mon through the grainstone interval, but are less com- mon higher in the core. Associated with /criodus in the grainstone interval are variable proportions of Be- lodella sp. cf. B. resima, Pseudooneotodus beckmanni, Decoriconus fragilis, Ozarkodina remscheidensis, O. excavata?, O.? planilinuga, and Oulodus elements. Barrick and Klapper (1992) interpreted the appear- ance of /criodus postwoschmidti in Oklahoma to rep- resent the level of the Cordilleran eurekaensis Zone, based on the co-occurrence of this species with Pe- davis biexoramus, which is known from the eurekaen- sis Zone in Nevada (Murphy and Matti, 1983). /criod- us woschmidti, the diagnostic species of the wosch- midti Zone, was not recovered from the core, nor is it known from Oklahoma (Barrick and Klapper, 1992). Because of the broad geographic distribution of /criod- us postwoschmidti (see synonymy in Barrick and Klapper, 1992), a zone based on this species has broad- er application than the Cordilleran eurekaensis Zone and we employ it here (Text—fig. 3). The base of the postwoschmidti Zone is well correlated with the grap- tolite succession, because /. postwoschmidti appears 1n the middle of the Monograptus uniformis Zone in the Barrandian succession in Bohemia (Sch6nlaub, 1980) and in the upper range of the M. uniformis Zone in Podolia (Mashkova, 1970; Drygant, 1984). The conodont fauna of the skeletal grainstones per- sists into the carbonate wackestones and mudstones that lie above it, but /criodus declines in abundance. Icriodus eolatericrescens? occurs at only one level, at 8165’—8162'. Lanea omoalpha first appears at 8150’ and recurs in the highest samples from the core, 8117’—-8111'. This species is the zonal index for the omoalpha Zone as used by Murphy and Valenzuela- Rios (1999), which lies at the base of the middle Loch- kovian. In summary, the conodont fauna of the Frame For- el 6c ol I I c € I I 1UUDUYIAG SNPOJOAUBOPNAS 8e cs E LI el I g 9 I € I € 9 Le SIPIIDAL SNUODMOIAG é9l Or oP 66 puusad jo -ds “g 6 ec c S L G DIDIIADOI “gq étl éC 6C él éT oP ée LI DIIvA{UD VIJapojag I él wdiiyd “qd G (F g é€ € IMAPSUD DIYODLOAC te Le 9T LT 8L or 8 T € (6 9 ik Ol SNIDISOIIUN SHPOsIPUD_ vy g9 9 6 8L 101 Il cl € c c I € satoads snpojisdvq l I Cc opul ‘ds snymmuss o a 2 w Ball Perdrix Fm. Lower Frasnian Up. Cairn Fm. Cooking Lake Fm. Maligne Fm. Ss Flume Fm. Cairn Fm. Elk Point Grp. Yahatinda Fm. Watt Mtn. Fm. West Alberta Arch Cambrian Text-figure 2.—Upper Devonian stratigraphic nomenclature for the Rocky Mountains, western Alberta and the central Alberta sub- surface (after Switzer et al., 1994). The Thornton Creek Member of the Flume Formation in the Alberta Rocky Mountains is equivalent to the basal Waterways Formation in the central Alberta subsurface to fine-sandstone of indeterminate age that overlays finely laminated Upper Cambrian dolomitic mudstones of the Lynx Formation (Text-figs. 4 and 5; Aitken, 1966). The contact between the Devonian and older Paleozoic rocks, locally a discontormity, is regionally an angular unconformity with progressively younger Paleozoic rocks underlying Devonian rocks to the east and west of the West Alberta Arch (McLaren, 1953; Pugh, 1973). FACIES Three mayor lithofacies comprise the Thornton Creek Member at its type section (Text-figs. 3, 4 and 5). These are: 1) laminated to burrowed argillaceous dolo-mudstone and calcareous shale, 2) fossiliferous, bioturbated, quartzose (silty to sandy) dolo-mud/wack/ packstones, and 3) dolomitic sandstones (Text-figs. 4 (=Lower T-R cycle A of Wendte et al., 1995, and Uyeno and and 5). The laminated to burrowed argillaceous dolo- Wendte, this volume). mudstone and calcareous shale are dark gray to dark brown, laminated to thin bedded, dominantly unfossil- SE Thornton Creek t—— SE Mt. Haultain —— t—— Haultain Cirque ——‘4 KR 82.0 km + 0.6 km ——_+ ——— ei eiKm ——+— 0.35 km —+0.20 km+ 020km +— 0.25 km A,C E,B,D il} G Q OF O/F F/P Type Section = 1 500 Thomton Cr. Mbr z : Basal 10 m x - | = Section A_ = = = 3 };450); | =| <£ | (s) | £ j 4200 oO. 8 | | 4 | | 350 | 3 S GB & = — —— 2 | | oO = c : i) =; i} = & REEDED | | U. disparilis Zone Oo : Background Facies and Fine-grained S55) eee paeeraea Facies) Platform/ 4] Sequence 1 Slope/Basin [22] Redeposited Facies, Sequences 3, 5, 7 Hl Slumps Shelf HBB Sequences 2, 4,6 Facies [J Background Facies and Fine-grained P Facies = Redeposited Facies, Sequences 4,6,8 — [#5] Megabreccias Sequences 3, 5, 7 Text-figure 3.—Cross-section of Middle and Upper Devonian strata along the southeast margin of the Ancient Wall platform illustrating lithostratigraphy, the sequence stratigraphic subdivision, and general lithofacies. Locations of measured stratigraphic sections are indicated by letters and graduated lines. The type section of the Thornton Creek Member of the Flume Formation of this report (indicated by diagonal ruled pattern at the base of the cross section) is the lower part of stratigraphic section A. Conodont sample locations and zones are indicated within ovals next to measured sections. Conodonts from Thornton Creek Member suggest a correlation with the late Givetian Upper subrerminus Fauna, younger conodont samples are correlated with Frasnian Montagne Noire (M.N.) zones of Klapper (1989). Ancient Wall platform sequences are indicated by alternating dark and light shades of gray. Slope and basin sequences are indicated by alternating white and stippled patterns. Thick, dashed black lines indicate sequence boundaries. Thin black lines within platform sequences indicate parasequence boundaries. The abbreviation C/M in the lithostratigraphy column on the left stands for the Cairn and Maligne formations (after Whalen er al., 2000a,b). THORNTON CREEK MEMBER: DAY AND WHALEN 27, A) Measured S ection _. Text-figure 4.—A. Outcrop photograph of the type section of the Thornton Creek Member of the Flume Formation (=section A illustrated in Text-fig. 5). Note the cyclic pattern of three parasequences comprising calcareous shale and argillaceous dolo-mudstones, overlain by quartzose dolo-mud/wackestones, and capped by dolomitic sandstones. Parasequences thin upward but internally facies coarsen and beds thicken upward. B. Field photograph of abundant Thallasinoides burrows (arrows) observed in argillaceous dolo-mudstones of the second 4th order parasequence. C. Field photograph of abundant silicified fossils (arrows) present in the quartzose dolo-mudstones and wackestones of the second parasequence. iferous except for locally abundant trace fossils con- sisting of simple indeterminate sub-horizontal burrows and burrow complexes of the ichnogenus Thallasino- ides. The quartzose dolo-mud/wackestones are medi- um gray to brown, thin to medium bedded, commonly thoroughly bioturbated, but locally contain abundant Thallasinoides burrows. Locally, this facies also con- tains monospecific to moderately diverse brachiopod assemblages described below. The dolomitic sandstone facies is medium to light gray or brown, thick bedded, well sorted, and either bioturbated or contains low- angle tabular sets of tangential cross-laminae. PARASEQUENCES The facies described above comprise three shallow- ing-upward cycles or parasequences (Text-figs. 4 and 5). Within each parasequence facies coarsen and beds thicken upward while individual parasequences thin upward. Facies grade upward from calcareous shale and argillaceous dolo-mudstones, to quartzose dolo- 128 e Cycle Hierarchy 4th 3rd Order para- sequences HST mfs TST Cambrian MWPGFIR BULLETIN 369 Lithology Dolo-Sandstone =| Quartzose Dolostone Argillaceous Dolostone Dolo- or Calc-Shale Grain Size/Carbonate Rock Type |__| Sand/Pack-Grainstones |__| Silt-Sand/Wacke-Packstones Clay-Silt/Mud-Wackestones Hl Clay/Mudstone Decreasing Accommodation Increasing Accommodation Text-figure 5.—Base of stratigraphic section A measured in 1998 (Text-fig. 3) illustrating the type section of the Thornton Creek Member (new unit) of the Flume Formation. Diagram illustrates thickness, grain-size, and clastic and carbonate lithologies, and third and fourth order cycle hierarchy. Shaded triangles illustrate variations in accomodation space in third (sequence) and fourth order (parasequence) cycles. Key to abbreviations in grain size/carbonate rock type column: C, St, Sd, G, B indicate clay, silt, sand, gravel, and boulder respectively, where M, W, P. G, F/R indicate mudstone, wackestone, packstone, grainstone, and floatstone/rudstone respectively. mud/wackestones, to dolomitic sandstones. Facies stacking within each parasequence is gradational and thinning-upward shales and argillaceous dolo-mud- stones are interbedded with quartzose dolo-mud/wack- estones. Marine flooding surfaces are indicated by the abrupt juxtaposition of argillaceous dolo-mudstone or calcareous shale above one or more parasequence-cap- ping beds of dolomitic sandstone. The dolomitic sand- stones increase in thickness and represent a greater proportion of each parasequence upsection. DEPOSITIONAL ENVIRONMENTS AND SEQUENCE STRATIGRAPHY The sedimentologic and paleontologic data provide criteria for interpretation of depositional environments and sequence stratigraphy. The laminated to thin-bed- ded, sparsely fossiliferous, argillaceous dolo-mud- stones and calcareous shales contain little evidence of Wave and current activity and record restricted to open marine conditions. The quartzose dolo-mud/wacke- stones yield both brachiopods and ichnofossils (Thal- lasinoides), and record dominantly open marine con- ditions. The lack of wave- and current-generated struc- tures might be attributed to intense bioturbation, there- fore position with respect to fair-weather wave base is equivocal. The bioturbated to cross-bedded dolomitic sandstones are interpreted to indicate deposition above fair-weather wave base, most likely in the middle to upper shoreface. The facies-stacking pattern within each parasequence records a change from restricted THORNTON CREEK MEMBER: DAY AND WHALEN 129 Biostratigraphy Brachiopods Eleuthrokomma wendtei n.sp. Schizophoria stelcki n.sp. Pseudoatrypa sp. Desquamatia (Independatrypa) sp. Cyrtina triquetra Cranaena sp. Strophodonta (S.) ae Moderate Diversity Fauna Conodont Icriodus subterminus Upper subterminus Fauna? = Upper ‘G00, Zone (Johnson and Klapper, Trace Fossil Thallasinoides (Cruziana |Ichnofacies) Open Marine Conditions Brachiopod Athyris vitatta. Low Diversity (monospecific) Fauna Restricted Marine Conditions 2 © Se | < & > Oe mY SS See “we > oo CStSdGB >) 7. Para- Sequences 3rd Order HST 5 mfs =| ae TST anES | r=" r——\ i—ay 0+ Cambrian MWPGFIR Text-figure 6.—Faunal data from stratigraphic section A illustrating the stratigraphic positions of the low-diversity restricted-marine Athyris Fauna (Table 1, samples 1F and 2F) and moderate diversity, open marine Eleutherokomma-Schizophoria brachiopod Fauna (Table 1, sample 3F), conodont, and trace fossils. Abbreviations as in Text-figure 5. shallow marine conditions to subtidal open marine conditions below fair-weather wave base, to shallow Open-marine conditions within fair-weather wave base. The sedimentologic and faunal data imply that the three parasequences represent one genetic sequence (Text-figs. 5 and 6). Parasequence | and the lower por- tion of parasequence 2 are interpreted as a Transgres- sive System Tract (TST) recording initially restricted and then open marine conditions (Text-fig. 5). The low-diversity Athyris-dominated faunas recovered from those intervals support this interpretation. Max- imum flooding occurs within the upper part of paras- equence 2 as indicated by the diverse and open-marine brachiopod fauna dominated by Eleutherokomma, Athyris, and Schizophoria (Text-figs. 5 and 6). The up- permost part of parasequences 2 and all of parasequ- ence 3 (Text-fig. 5) are interpreted as High-Stand Sys- tem Tract (HST). The thinning-upward nature of the parasequences and the increase in thickness and pro- portion of dolomitic sandstone upsection (Text-figs. 4 and 5) indicate progradation and decreasing accom- modation space. CONODONT AND BRACHIOPOD FAUNAS OF THE THORNTON CREEK MEMBER CONODONTS The base of the ramp carbonates of the Flume For- mation at the Ancient Wall reef complex is correlated by McLean and Klapper (1998) with the norrisi Zone (=Lowermost asymmetricus Zone of the older cono- dont zonation) (Text-fig. 7). Uyeno (1987) recovered 130 BULLETIN 369 Conodont Zones Stages Basin Land triangularis Z undifferentiated U. subterminus F.? = U. disparilis Ze - Thornton Cr. Mbr —_ L. subterminus F Text-figure 7.—Diagram illustrating the Middle to Late Devonian conodont zonation, western Alberta lithostratigraphy, and a second order sea level curve. The second order curve also illustrates a series of higher-frequency transgressive-regressive (T-R) cycles document- ed in North America and Europe (Ila-d of Johnson er al., 1985). Transgressive-Regressive Cycle Ila was subdivided into T-R cycles Ila-1 and Ila-2 by Day er al. (1996). Conodonts recovered from the Thornton Creek Member of the Flume Formation suggest correlation with the Upper subterminus Fauna was deposited during T-R cycle Ha-2 (after Johnson ef al., 1985; Day ef al., 1996; McLean and Klapper, 1998). Pandorinellina insita in the basal Flume Formation at the Cold Sulphur Spring section (see his fig. 28, GSC samples 12NBd and 12Nbe) approximately 25 km southeast of the Ancient Wall reef complex. At the type section of the Thornton Creek Member, the conodont /criodus subterminus was recovered in sample 3F (parasequence 2) in association with bra- chiopods of the Eleutherokomma-Schizophoria Fauna described below. The position of the Thornton Creek Member (with /criodus subterminus) below the base of the ramp carbonate succession of the remainder of the Flume suggests a pre-norrisi Zone correlation within the interval of the late Givetian Upper subter- minus Fauna. Pandorinellina insita or other species of the late Givetian norrisi Zone have not been recovered in sequence from Flume carbonates overlying the Thornton Creek Member in our samples from section A at Thornton Pass. The Upper subterminus Fauna is a shallow-water conodont fauna considered to be equivalent to all or part of the Upper disparilis Zone of the Devonian co- nodont zonation (Johnson and Klapper, im Johnson, 1990). The first occurrence of Polygnathus angustidis- cus with Icriodus subterminus, below the first occur- rence of Pandorinellina insita and/or Skeletognathus norrisi, defines the interval of the Upper subterminus Fauna of Witzke er al. (1985). BRACHIOPODS At the proposed type section (section A, Text-figs. 3—6) at Thornton Pass south of the Ancient Wall, reef platform brachiopods were recovered from parasequ- ences | and 2 of the Thornton Creek Member (Text- fig. 6; Table 1). The low-diversity assemblages of sam- ples 1F and 2F (Table 1; Text-fig. 6) consisting of Athyris sp. or A. vittata are designated as the Athyris Fauna. The moderately diverse fauna of sample 3F (Table 1; Text-fig. 6) from the upper part of parase- quence 2 is referred to as the Eleutherokomma-Schi- zophoria Fauna. Athyris Fauna Mudstones in the lower part of parasequence | (Ta- ble 1, sample 1F) yield shells (partially decalcified) of Athyris sp. Dark gray dolomitic mudstones in the low- er part of parasequence 2 (Table 1, sample 2F) yield a similar low-diversity brachiopod assemblage con- sisting entirely of Athyris vittata from 4.9—5.1 meters. This monospecific assemblage suggests restricted ma- rine conditions during initial transgression, and is sim- Table 1.—Late Givetian brachiopod faunas in the Thornton Creek Member (samples 1F—3F) and overlying carbonates of the Flume Formation (sample 4F) at the type section of the Thornton Creek Member, Thornton Pass, Jasper National Park, Alberta. Sample number 1F 2F 3F 4F Sample elevation (m above base of Devonian) 19) 49 5.2-6.5 Athyris sp. 29 0 0 0 A, vittata 0 25 210 0) Eleutherokomma wendtei n.sp. 0 0) 266 0) Schizophoria (S.) stelcki n.sp. 0 0) 98 10) Desquamatia (Independatrypa) sp. 0 0 3 0 Pseudoatrypa sp. ct. P. gigantea 0 0 18 10) Cyrtina triquetra 0 10) 54 10) Cranaena sp 0 0) 7] 10) Strophodonta (S.) sp. 0 10) ] 10) Athyris sp. cf. A. simplex (0) (0) 0 27 Total specimens per sample 29 25 657 27 Weight of sample acidized 8 kg I kg Parasequence 1 2 2 4 THORNTON CREEK MEMBER: DAY AND WHALEN 131 ilar to other coeval inner-shelf, shallow-water brachio- pod associations dominated by Athyris and shallow- water conodont associations of the Upper subrerminus Fauna. These include athyroid faunas reported from the Devils Gate Limestone at Devils Gate (Drake, 1978; Johnson er al., 1980, p. 89) in central Nevada, and the Gizzard Creek Member of the Coralville For- mation in central Iowa (upper part of the Tecnocyrtina Fauna of Day, 1992, p. 75). Eleutherokomma-Schizophoria Fauna The overlying, moderately diverse brachiopod as- semblage in the middle and upper parts of parasequ- ence 2 is referred to as the Eleutherokomma-Schizo- phoria Fauna (Table 1, sample 3F). This fauna occurs in quartzose dolo-mud/wackestones from 5.2 to 6.5 meters above the base of the type section. Elements of the Eleutherokomma-Schizophoria Fauna are associ- ated with the conodont /criodus subterminus and trace fossils including Thallasinoides. The Eleutherokom- ma-Schizophoria Fauna is dominated by the spiriferid E. wendtei n. sp. and the orthoid Schizophoria (S.) stelcki n. sp.; less abundant are: Athyris vittata Hall (1850), Cyrtina triquetra Hall (1860), the atrypoids Pseudoatrypa sp. cf. P. gigantea and Desquamatia (Independatrypa) sp., the terebratuloid Cranaena sp., and a single poorly preserved specimen of Stropho- donta (S.) sp. The middle-shelf brachiopod fauna and ichnofossils in the middle and upper parts of parase- quence 2, above the sparse faunas of parasequence | and lower part of 2, support the interpretation of max- imum flooding (highstand) during deposition of this part of parasequence 2. Our proposed correlation of the Thornton Creek Member of the Flume Formation with the Upper sub- terminus Fauna suggests that Eleutherokomma wendtei n. sp. is the oldest species of the genus known in west- ern Canada. The only North American species that is older than E. wendtei n.sp. is E. extensa described from the late Givetian Onate Formation in the northern Sacramento Mountains of southern New Mexico by Cooper and Dutro, 1982). The slightly older clastic shelf and basinal deposits of the Onate were deposited during the initial transgression of Devonian T-R cycle Ila, or T-R cycle Ila-1 of Day et al. (1996), based on data and correlations presented in Day (1988, 1989b, 1992, 1998). All previously described species of genus Eleutherokomma Crickmay, 1950, in western Canada are from deposits spanning the interval correlated with the norrisi Zone (latest Givetian) through Montagne Noire Zone 9-10 (upper part of middle Frasnian). The occurrence of Pseudoatrypa sp. aff. P. gigantea (Webster, 1921) in the Thornton Creek Member (Table 1, sample 3F) in western Alberta is slightly younger than occurrences of P. gigantea in the upper part of the Little Cedar Formation of central and eastern Iowa. There it occurs in the interval of the Neatrypa water- looensis Zone (Day, 1992, 1996) associated with co- nodonts of the Lower subterminus Fauna. Similar forms reported by Warren and Stelck (1956) and Nor- ris (1963, in Norris and Uyeno, 1981) are all from the younger latest Givetian and early Frasnian deposits of the Waterways Formation in northeastern Alberta (see below). The subtidal marine brachiopod fauna of the Thorn- ton Creek Member indicates development of fully open marine conditions along the western margin of the West Alberta Arch, associated with a major trans- gression in the interval of the Upper suwbterminus Fau- na in the late Givetian, prior to the widespread trans- gression that initiated Devonian T-R cycle Ib of John- son et al. (1985). The overlying carbonates of the re- mainder of the Flume were deposited during T-R cycle IIb. Athyroid, atrypoid, rhynchonellioid and spiriferoid brachiopods have been described from carbonate fa- cies making up most of the Flume Formation at a va- riety of locations in the Alberta Rocky Mountains (McLaren, 1954, 1962; McLaren et al., 1962), and the undifferentiated Flume Formation of southeastern Brit- ish Columbia (Maurin and Raasch, 1972). Brachiopod assemblages from the lower part of the undifferenti- ated Flume Formation at the Kawka and Cecelia lakes areas of eastern British Columbia (illustrated in Maur- in and Raasch, 1972) are dominated by atrypoid bra- chiopods and are of similar age to the Thornton Creek Member whose fauna is dominated by athyrioid, spi- riferoid, and orthoid brachiopods, and smaller propor- tion of atrypoids. North and northeast of the West Alberta Arch, sparse brachiopod faunas consisting of two to three species are reported from coeval deposits of the late Givetian Slave Point Formation in northern Alberta and the southern N.W.T (Text-fig. 8). The low diver- sity of the Slave Point brachiopod fauna associated with conodonts of the suwbterminus Fauna indicates more restricted conditions in those parts of the Western Canadian Sedimentary basin. CORRELATION OF THE THORNTON CREEK MEMBER, FLUME FORMATION NORTHEASTERN BRITISH COLUMBIA The lower part of the Flume Formation in the Kak- wa-Cecilia lakes area of eastern British Columbia (B.C.) has been correlated with the Slave Point For- mation of northeastern Alberta and the Pine Point area of the southern NWT (Text-fig. 8) by Norris and Central Alberta NE. Alberta- Subsurface | Great Slave Lake Area Southeast British Columbia Conodont Zone-Fauna Western Alberta SYSTEM n e iv Ww 7) U) < E 2) i | & Qa a | a Zz = = Ww = 18} MN Zone 2 MN Zone 1 DEVONIAN FLUME FM Assemblage FLUME FM Thornton | undiffer. WATERWAYS FM subterminus Fauna N.E. Alberta & Northwest Territories BULLETIN 369 lowa Basin Carbonate Platform Eastern & Central Central Easter) Nevada: Antelope Range DEVONIAN TR Central CYCLES Missouri W. Powell Creek Area “upper unit” Callaway () Limestone Point Wilkins Mb CEDAR VALLEY FM. GUILMETTE FM. Sequences -SOURIS RIVER FM. Limestone UPPER DENAY LIMESTONE Devonian T-R Cycle Stratotype Ila-1 (upper part) Text-figure 8—Correlation chart for late Givetian and early Frasnian units in western and central North America showing proposed corre- lations of the Thornton Creek Member (new unit) of the Flume Formation. See text discussion for references on the stratigraphy and biostra- tigraphy of units shown. Transgressive-Regressive Cycles Ila and IIb after Johnson er al. (1985), and subdivisions after Day et al. (1996) and Uyeno (1998). Conodont zones after Klapper (1989), and Klapper and Johnson, in Johnson (1990). Abbreviations, from left to right: FRASN. = Frasnian; MN = Frasnian Montagne Noire conodont zones of Klapper (1989); FM. = Formation; Mb. = Member; N.E. = Northeast; S.W. = Southwest. Uyeno (in Braun et al., 1989, see area 8 of their text- fig. 2), and other coeval late Givetian units in central Canada and the central and western United States by Day (1997, 1998). The brachiopod sequence in the Flume at the Kakwa Lake and Wallbridge Mountain sections of Maurin and Raasch (1972) indicates that the faunas that include the brachiopods Tecnocyrtina missouriensis raaschi, Cyrtina triquetra, Schizophoria (S.) “‘meeki,” with species of Desquamatia (Indepen- datrypa), Pseudoatrypa, and possibly Desquamatia (Seratrypa) of their Assemblage I] and most of As- semblage II, are correlative with the Slave Point For- mation of northern Alberta and the southern NWT, and the Thornton Creek Member of the Flume Formation in the Rocky Mountains of western Alberta. The co- nodont fauna and biostratigraphy and detailed analysis of the carbonate sedimentology and sequence stratig- raphy of the Flume Formation in the Kakwa Lake and Wallbridge Mountain sections of northeastern British Columbia have yet to be fully documented. CENTRAL ALBERTA Based on the conodont and brachiopod faunas, the Thornton Creek Member can be correlated with strata making up the basal Waterways Formation in the sub- surface of central Alberta (Text-fig. 8). There shales and carbonates make up the basal Beaverhill Lake Group Transgressive-Regressive (T-R) cycle Lower A of Wendte ef al. (1995, fig. 2) and Uyeno and Wendte (this volume, Text-fig. 6) that yields conodonts of the Upper subterminus Fauna. Consequently, deposition of the Thornton Creek Member and the lower Waterways Formation in the subsurface of eastern and central Al- berta (Uyeno and Wendte, this volume, Text-fig. 4) coincided with the deepening event initiating Devo- nian T-R cycle Ha-2 of Day er al. (1996). A recent sequence stratigraphic analysis by Potma et al. (2001) defined three depositional sequences within the Beay- erhill Lake Group. Based on the limited biostratigraph- ic data provided in Potma er al. (2001), the Thornton Creek Member seems to correlate with the lower part of their Beaverhill Lake Group Sequence 1. WESTERN ALBERTA SUBSURFACE Based on information summarized in Elliott and Johnson (1997, pp. 183-184) and Elliott et al. (2000, pp. 123-124), it is possible that part of the Yahatinda Formation in parts of western Alberta may represent peritidal or terrestrial coastal plain equivalents of the Thornton Creek Member of the Flume Formation (Text-fig. 2). Spore and vertebrate data cited in Elliott et al. (2000) are equivocal and do not permit precise correlation with the marine conodont sequence, and hence could be somewhat older than the Flume For- mation and the basal Waterways Formation in the cen- tral Alberta subsurface. Recent study of the Yahatinda Formation in south-central Alberta identified a series of twelve intertidal-supratidal dolostone couplets, nine of which were interpreted as paleosol chronosequences (Williams and Krause, 2000). The base of the Yaha- tinda section is a shallow subtidal to intertidal wack- estone that unconformably overlies the Cambrian El- don Formation (Williams and Krause, 2000). The low- er seven Yahatinda couplets display carbon isotopic signatures that reflect a marine carbon source, but the signature abruptly changes to a continental source in couplet eight (Williams and Krause, 2000). Overlying couplets contain green friable shales interpreted as ma- THORNTON CREEK MEMBER: DAY AND WHALEN 133 rine or restricted marine mudstones, implying renewed marine influence and possibly transgression (Williams and Krause, 2000). The marine succession of the Thornton Creek Member may correlate with the all or a portion of the first seven Yahatinda couplets and the underlying wackestone identified by Williams and Krause (2000). The continental influence recorded in couplet eight of Williams and Krause (2000) could represent either the relative fall of sea level that ter- minated the Thornton Creek Member (i.e., T-R cycle Ila-2) deposition or, perhaps, the early Frasnian ex- posure surface reported at the top of the Utopia Mem- ber of the Flume Formation by Noble (1970) and Cook @972): NORTHEASTERN ALBERTA In the Wood Buffalo National Park area in north- eastern Alberta, conodonts recovered from the Slave Point Formation include Polygnathus angustidiscus and Icriodus subterminus (=Upper subterminus Fau- na) below strata of the Waterways Formation (Text- fig. 8) with conodonts of the Pandorinellina insita Fauna (Norris and Uyeno, 1983; Norris and Uyeno, in Day et al., 1996). In outcrop, the Slave Point Forma- tion of northern Alberta yields a sparse brachiopod fauna that suggests more restricted conditions in this region of the northern platform than in western Alberta and eastern British Columbia. Norris (1965; in Norris and Uyeno, 1981, 1983; in Day et al., 1996) and Day (1998) reported a sparse megafauna from the Slave Point Formation in both northern Alberta and equiv- alents in the southern NWT that includes Desquamatia (Independatrypa) sp. cf. D. UI.) independensis, Eman- uella vernilis, and the coral Grypophyllum macken- ziense, associated with ostracodes of the late Givetian DM 9 Biozone of Braun (see discussion of ostracode faunas and correlations by Braun, in Braun ef al., 1989). NORTHWEST TERRITORIES—GREAT SLAVE LAKE AND POWELL CREEK AREA In the Pine Point area along the south shore of Great Slave Lake, the Amco Member of Slave Point For- mation unconformably overlies the **Watt Mountain” Formation (Text-fig. 8) and consists of blue-gray, high- ly argillaceous skeletal mudstone and wackestones, and variably fossiliferous sandy mudstones (Braun et al., 1989; Norris and Uyeno, in Day et al., 1996: Nor- ris, 1998). Lantos (1983) reported Polygnathus aft. P. brevilaminus (=P. angustidiscus) from the Amco Member in the Pine Point in the subsurface of the area, which permits correlation with the Upper subterminus Fauna (see discussion by Uyeno in Day et al., 1996; Uyeno, 1998). Uyeno’s (1998, p. 156) samples from the undivided Slave Point there did not yield cono- donts. The Thornton Creek Member would correlate with the lower part of the Allochthonous Beds in the Powell Creek area of the central Mackenzie River Val- ley, based on the occurrence of conodonts of the Low- er subterminus Fauna by Uyeno (1979, 1998) and Mc- Lean and Klapper (1998). GREAT BASIN—CENTRAL AND EASTERN NEVADA Equivalents of the Thornton Creek Member in the Great Basin of the western United States (Text-fig. 8) include part of the Upper Denay Limestone and Guil- mette Formation of central and eastern Nevada, re- spectively, and part of the Devils Gate Limestone at its type section near Eureka, Nevada (not shown in Text-fig. 8). Brachiopod faunas of the Lower Tecno- cyrtina Community of Johnson (1990, figs. 2 and 35) are associated directly with conodonts of the Upper disparilis Zone in the Upper Denay Limestone in mea- sured sections III, IV, V, and X in the Antelope Range of central Nevada (see Johnson ef al., 1980, fig. 4: Johnson et al., 1996, fig. 3). The associated brachiopod and conodont faunas above characterize late Givetian Great Basin Devonian Faunal Interval (FI.) 27 of Johnson (1977, 1990), Johnson et al. (1980), and John- son and Trojan (1982). The Devonian (Pragian-Fa- mennian) succession in the Antelope Range of central Nevada was selected as the principal reference suc- cession (Johnson et al., 1996) for global eustatic sea level cycles (Devonian Transgressive-Regressive Cy- cles Ia to IIb of Johnson er al., 1985). Although John- son et al. (1996, p. 8, fig. 3) did not formally subdivide Devonian T-R cycle Ila of Johnson et al. (1985), they outlined lithologic evidence for an intra T-R cycle Ha deepening event coinciding with the first occurrence of brachiopods and conodonts of Great Basin Devo- nian EI. 27 just above bed 1340 in their “Upper V” section. Day et al. (1996) designated this intra T-R cycle Ila deepening event as Devonian T-R cycle Ila- 2, based on stratigraphic and biostratigraphic analysis of cratonic carbonate platform successions in Iowa, Manitoba, and northern Alberta and the southern NWT of western Canada. LaMaskin and Elrick (1997) identified eleven Giv- etian through early Famennian sequences within the Guilmette Formation of eastern Nevada and western Utah. Their analysis suggested that the second se- quence (sequence 2 of their figs. 2, 10, 11) was de- posited during the disparilis Zone and may have been initiated by T-R cycle Ia-2 of Day ef al. (1996). Cor- relation of this sequence is equivocal because samples through that interval are zonally indeterminate. How- 134 BULLETIN 369 A. Late Givetian B. Latest Givetian-Early Frasnian 110 58 118 114° OF. 118 114 2\ Peace River Arch and Fringing Reef Erosional 4 Edge 56° Great Approximate oe location of West Alberta : Swan Hills —— ~ Reets Arch & \ & | ie \ & Incipient Redwater Reef Outline of Frasnian Ancient Wall Platform C. Mid-Late Frasnian 118° Erosional Key tr] Paleolandmass “] Silicilastic Facies [| Slope/Basin Facies <<] Restricted Platform Facies Mixed Carbonate- Siliciclastic Facies ‘AA, Carbonate Ramp Facies 4 Reef Complexes ~. Approximate < Outline of West Alberta Arch Thrust Faults, Palinspastically Restored Pid 0 100 $50° Text-figure 9.—Paleogeographic maps showing facies distributions in western and central Alberta during the upper Middle (late Givetian) to lower Upper Devonian (Frasnian). Palinspastically restored thrust faults in the Rocky Mountains are shown in southwestern parts of each map. A. Late Givetian: the West Alberta Arch was emergent and served as a sediment source for the Yahatinda Formation and the Thornton Creek Member of the Flume Formation. The area underlying the southeast margin of the Ancient Wall platform was inundated by the late Givetian transgression of T-R cycle Ha-2 of Day er al. (1996), followed by open marine waters where mixed carbonate-siliciclastic units of the Thornton Creek Member were deposited. East of the West Alberta Arch initial Swan Hills reefs were deposited surrounded by carbonate THORNTON CREEK MEMBER: DAY AND WHALEN 135 ever, their sequence 2 is bracketed by sequences that yield diagnostic conodont faunas (LaMaskin and El- rick, 1997), and based on its stratigraphic position it appears to be correlative with the Thornton Creek Member of the Flume Formation. CENTRAL CANADA—WILLISTON BASIN OF MANITOBA AND SASKATCHEWAN In southwestern Manitoba, equivalents of the Thorn- ton Creek Member of the Flume Formation are the argillaceous limestone beds of the Point Wilkins Mem- ber of the Souris River Formation (Text-fig. 8). The diagnostic megafossils of the argillaceous limestone beds of the Point Wilkins Member (see Norris, in Nor- ris et al., 1982; fig. 5 of Norris, Uyeno, and Day, in Day er al., 1996; Day, 1997) include Desquamatia (In- dependatrypa) cf. D. UI.) independensis, Athyris vitta- ta, Emanuella cf. E. subumbona, Cyrtina triquetra, Tecnocyrtina missouriensis missouriensis, and Cran- aena sp. cf. C. iowensis. Conodonts of the Upper sub- terminus Fauna occur with the brachiopod Desqua- matia (1.) independensis in Unit B of the Davidson Member of the Souris River Formation of Saskatche- wan. The associated conodont and brachiopod faunas indicate correlation with the Slave Point Formation of northern Alberta and, by extension, with the Thornton Creek Member of the Flume Formation of western Al- berta. IOWA BASIN OF THE CENTRAL UNITED STATES The Thornton Creek Member of the Flume Forma- tion of western Alberta can be correlated with the Cor- alville Formation and Mineola Limestone of the Cedar Valley Formation of the central and southern parts of the Iowa Basin, respectively (Text-fig. 8). The Coral- ville Formation of the central and northern part of the Iowa Basin makes up a single carbonate-dominated depositional sequence aligned with the upper part of T-R cycle Ha of Johnson er al. (1985), or T-R cycle Ila-2 by Day et al. (1996). Transgressive facies of the Coralville (Gizzard Creek and lower Cou Falls mem- bers) yield conodonts of the Upper subterminus Fauna (Witzke er al., 1985; Witzke et al., 1989; Witzke and Bunker, 1997; Bunker and Witzke, 1992; Day et al., 1996; Day, 1996, 1997), and brachiopod faunas of the Tecnocyrtina johnsoni Zone (Day, 1997). Equivalent deposits along the southern margin of the Iowa Basin in central Missouri are skeletal grainstones and pack- stones of the Mineola Limestone of the Cedar Valley Formation (Thompson, 1993; Day, 1997). Day (1997) reported conodonts of the Upper subterminus Fauna from the Mineola, directly associated with a moder- ately diverse brachiopod fauna that includes Tecno- cyrtina missouriensis missouriensis, Cyrtina triquetra, Tylothyris sp., Athyris sp., Schizophoria sp., Cranaena sp. cf. C. iowensis, Strophodonta (S.) sp., and Penta- merella sp. INITIAL FLUME FORMATION ONLAP OF THE WESTERN ALBERTA ARCH AND IMPLICATIONS FOR LATE GIVETIAN SEA LEVEL HISTORY OF NORTH AMERICA Previous stratigraphic analyses have documented deepening events coincident with the timing of sea lev- el rises initiating eustatic Devonian T-R cycle Hb-IIf of Johnson et al. (1985, 1991) in the Rocky Mountains of western Alberta (Moore, 1989; McLean and Mo- untjoy, 1993; van Buchem et al., 1996; Whalen et al., 2000a,b). Correlations and distribution of strata de- posited during the major eustatic sea level rise of De- vonian T-R cycle Ifa-2 are documented in the subsur- face on the east flank of the West Alberta Arch by Wendte (1992), Campbell (1992) and Wendte ef al., (1995), and Uyeno and Wendte (this volume); in northeastern Alberta by Norris and Uyeno (in Day et al., 1996), Norris (1998), and Uyeno (1998); and in the lower and upper Mackenzie River Valley by Uyeno (1998). As outlined above, equivalent strata have also been documented in the Great Basin of the western U.S. (Johnson et al., 1996; LaMaskin and Elrick, 1997), the U.S. mid-continent and central Canada (Day, Witzke and Bunker, in Day et al., 1996; Witzke and Bunker, 1997). The Thornton Creek Member of the Flume Formation represents the first documenta- tion of strata deposited during Devonian T-R cycle Ila- 2 of Day et al. (1996) in the Canadian Rocky Moun- tains of western Alberta (Text-fig. 8). Correlations of the Thornton Creek Member out- lined above (Text-figs. 7 and 8) provide new con- straints on the timing and pattern of onlap of the West 7 ramp deposits of the Slave Point Formation. B. Latest Givetian to early Frasnian time: the West Alberta Arch was inundated by marine transgression (T-R cycle IIb of Johnson et al., 1985, 1991; T-R cycle IHb-1 of Day et al., 1996) and blanketed by distal deposits of the regionally extensive upper Flume Formation carbonate ramp. Swan Hills reefs reached their maximum development along the eastern margin of the submerged West Alberta Arch, central and eastern Alberta were sites of mixed carbonate-siliciclastic shallow marine deposition. C. Remainder of the Frasnian: western and central Alberta were sites of isolated carbonate platform and associated basinal sedimentation. After Mountjoy (1980), Moore (1989), Morrow and Geldsetzer (1988), Oldale and Munday (1994), Switzer et al. (1994), and Whalen er al. (2000a,b) BULLETIN THORNTON CREEK MEMBER: DAY AND WHALEN 137 Alberta Arch (Text-figs. 7-9). Prior biostratigraphic data indicated that onlap along the western flank of the Arch began no earlier than the latest Givetian (norrisi Zone). Our new data indicate a late Givetian age for the initial onlap during the interval of the Upper sub- terminus Fauna (Text-figs. 7 and 8). The high silici- clastic content of the Thornton Creek Member, and the lack of all but very fine-grained siliciclastics through- out the Frasnian units in the area, imply that the West Alberta Arch was partially exposed and _ probably served as a source for locally derived siliciclastic sed- iments of the Thornton Creek Member and its possible equivalent to the southeast (Yahatinda Formation; Text-fig. 9). By earliest Frasnian time, this local source had been onlapped and buried beneath the regionally extensive Flume ramp (Text-fig. 9). SYSTEMATIC PALEONTOLOGY Illustrated specimens and additional material from samples A98-1 to 3 from the Thornton Creek Member of the Flume Formation are housed in the Geological Survey of Canada (GSC) repository in Ottawa, Ontar- io. Preparation of standard serial sections of shells was not possible because all specimens recovered from the Thornton Creek Member are silicified. The single frag- mental specimen (GSC 122846) of Strophodonta (S.) sp. Hall, 1852, discussed above (see Table 1) is too poorly preserved to warrant illustration. The system- atic classification of the order Orthida follows Wil- liams and Harper (2000), Alvarez et al. (1998) for the Order Athryida, and Carter et al. (1994) for the spi- riferid brachiopods. Phylum BRACHIOPODA Dumeril, 1806 Subphyllum RHYNCHONELLIFORMEA Williams, Carlson, Brunton, Holmer, and Popoy, 1996 Class RHYNCHONELLATA Williams, Carlson, Brunton, Holmer, and Popoy, 1996 Order ORTHIDASchuchert and Cooper, 1932 Suborder DALMANELLIDINA Moore, 1952 Superfamily ENTELETOIDEA Waagen, 1884 Family SCHIZOPHORIIDAE Schuchert and Levene, 1929 Genus SCHIZOPHORIA King, 1850 Subgenus SCHIZOPHORIA (SCHIZOPHORIA) King, 1850 Type species.—Conchyliolithus (Anomites) respinu- atus Martin, 1809, pl. 49, figs. 13-14. Schizophoria (Schizophoria) stelcki new species Plate 1, figures 1-10 Diagnosis.—Medium to large species of Schizo- phoria (up to 34 mm in width), width exceeds length. Subcircular shell outline with minor, or lacking, ante- rior indentation. Anterior commissure unisulcate with high subangular ventral tongue of sulcus strongly de- flected at almost 90° relative to commissural plane. Description.—Medium to large dorsibiconvex shell (up to 34 mm in width), width greater than length, anterior commissure broadly unisulcate with relatively PLATE | Brachiopods from the Thornton Creek Member of the Flume Formation. All specimens from sample 3F from section A at GSC Thornton Pass locality, Ancient Wall Reef Platform, Jasper National Park, Alberta, Canada. All specimens *1.5 unless otherwise indicated. 1-10. Schizophoria (Schizophoria) stelcki new species. 1-4. GSC 122847 (syntype): internal, external (upper), lateral, and anterior views of complete ventral valve. 5, 6. GSC 122848 (syntype): internal and external views of complete dorsal valve. 7. GSC 122849 (paratype): upper view of relatively complete ventral valve embedded in matrix. 8. GSC 122851 (paratype): internal view of ventral valve. 9. GSC 122852 (paratype): internal view of dorsal valve. 10. GSC 122853 (paratype): internal view of dorsal valve. 11, 12. Desquamatia (Independatrypa)? species. Figured specimen. GSC 122871. External and internal views, respectively of partial dorsal valve showing socket plates and damaged bases of crura. 13-24. Athyris vittata Hall, 1860. 13-17. GSC 122862. 13. Internal view of dorsal valve. 14, 15, 17. External (normal to commissural plane), standard and oblique internal views, respectively of ventral valve; 16. anterior view of articulated valves showing gape. 18-20. GSC 122863. Right lateral, anterior, and dorsal views, respectively, of complete shell. 21-24. GSC 122864. Dorsal, posterior, anterior, and left-lateral views, respectively of complete shell. 138 BULLETIN 369 high subangular ventral tongue strongly deflected at almost 90° relative to commissural plane. Anterior dor- sal sulcus deep, originating anterior of midlength. Shell subcircular in outline, rounded outline along an- terior margin lacking medial anterior indentation at po- sition of medial sulcus and tongue, maximum width at midlength. Dorsal valve highly convex with planocon- vex ventral valve. Exterior of both valves with poorly preserved fine radial costellae. Dorsal valve strongly convex, and in anterior view maximum lateral convexity at midline with shell sur- face sloping to lateral margins, in lateral view maxi- mum longitudinal convexity just posterior of mid- length. Short triangular anacline dorsal interarea, short open triangular notothyrium formed by convergence of the short dental and crural plates of cardinalia. Dental plates diverge anteriorly at approximately 70° imme- diately below the beak from medial cardinal margin. Dorsal interior with poorly preserved cardinal process consisting of simple short elongate ridge originating from valve floor immediately below beak. Short socket plates diverge from cardinal margin below beak at 65— 75°, fulcral plates flooring sockets join socket plates along postero-lateral forming two shallow lateral cav- ities as seen in most species of the genus. Stout crura arise from socket plates and are strongly recurved ven- trally diverging anteriorly at same angle as dental plates and bound the notothyrial cavity. Bilobed ad- ductor muscle scars extending anteriorly from noto- thyrial cavity approximately along 20% of the arc length of valve floor, the two adductor lobes separated by low weakly developed medial ridge or myophragm, bounded at their lateral and anterior margins by weak- ly to moderately developed ridges originating as ex- tensions of bases of socket plates along margins of muscle field. Four weakly to strongly impressed pallial trunks extend anterior of forward edge of the ridge bounding muscle field as is typical for most species of the genus (see Schuchert and Cooper, 1932, pl. 23). Ventral valve with open triangular delthyrium; slightly concave apsacline interarea, width averages 65% of maximum valve width. Gently convex with maximum convexity at 20% of shell length just ante- rior of beak. Sulcus originates anterior of midlength (at 60% length anterior of beak), becomes strongly de- flected at almost 90° relative to commissural plane close to anterior margin (75—85% of length anterior of beak), medial anterior tongue subangular in outline, width of deflected shell margin of tongue 60—65% of maximum shell width. Ventral interior with deep del- thyrial cavity, strong teeth arising from well-developed dental plates that extend anteriorly on floor of the valve to along the margins of the muscle field. Ad- ductor muscle field bilobed, divided medially along its length by strong medial diductor ridge with anterior end of ridge often thickened and elevated slightly above ridge bounding muscle field, forward lobate ridges along margins of adductor scars extend anterior of shorter diductor ridge. Lacks a medial ridge anterior of edge of muscle field. Muscle field longer than wide extending on floor of valve 25—35% of length. Types.—Syntypes are the isolated ventral valve GSC 122847 and the dorsal valve GSC 122848. Four illustrated paratypes including GSC 122849, 122851, to 122853. Nine unfigured paratypes numbered GSC 122850, 122854 to 122861. Other material examined.—Includes 87 unnum- bered valves consisting of 23 partial dorsal valves and 64 partial ventral valves from the type locality. Type stratum and locality.—The type stratum is the 1.5 meter interval of sample 3, section A, at Thornton Pass, in Jasper National Park, Alberta Rocky Moun- tains, with type locality coinciding with the type sec- tion of the Thornton Creek Member of the Flume For- mation, GSC Thornton Pass locality. Etymology.—Named in honor of Dr. Charles Stelck (Professor of Geology Emeritus, University of Alber- ta) for his pioneering contributions to the knowledge and understanding of the Paleozoic and Mesozoic stra- tigraphy and paleontology of western Canada. Occurrence.—As currently known, it is restricted to the late Givetian Eleutherokomma-Schizophoria Fauna (Table 1, sample 3F; Text-fig. 6) of the Thornton Creek Member of the Flume Formation of the Alberta Rocky Mountains. Discussion.—Schizophoria (S.) stelcki is similar to both S. (S.) athabaskensis Warren, 1944, and S. (S.) allani Warren, 1944, described from the latest Givetian and early Frasnian Waterways Formation of northern Alberta. All three forms have prominent medial ventral tongues, although S. (S.) stelcki n.sp. differs in that its tongue is proportionally longer than that of S. (S.) ath- abaskensis, not as angular or V-shaped in outline as that of S. (S.) allani, and is deflected at the anterior margin at almost at 90° relative to the commissural plane. When viewed dorsally, the outline of the ante- rior margin of S. (S.) stelcki is rounded and is not indented medially, versus the somewhat lobate-indent- ed anterior outlines of both of the Waterways species. It also differs from S. (S.) allani in its larger adult size. It differs from S. (S.) athabaskensis by its somewhat smaller adult shell size, internally in its proportionally narrower ventral adductor muscle field and bounding ridges, and it lacks the medial ridge of the Waterways form that extends anterior of the ventral muscle plat- form and medial adductor ridge. The internal shell fea- tures of S. (S.) allani are unknown (Norris, 1983, p. 10). THORNTON CREEK MEMBER: DAY AND WHALEN 139 Order ATHYRIDIDA Boucot, Johnson and Staton, 1964 Suborder ATHYRIDIDINA Boucot, Johnson and Staton, 1964 Superfamily ATHYRIDOIDEA Davidson, 1881 Family ATHYRIDIDAE Davidson, 1881 Subfamily ATHYRIDINAE Davidson, 1881 Genus ATHYRIS M’Coy, 1844 Type species.—Terebratula concentrica Buch, 1834, p. 123 [see discussion of new lectotype for Afhyris concentrica (Buch, 1834) by Grunt and Racki, 1998, pp. 365-366] Athyris vittata Hall, 1860 Plate 1, figures 13-24 Athyris vittata Hall, 1860, pp. 89-90; Hall, 1867, p. 289, pl. 46, figs. 1-4; Hall and Clark, 1893, p. 90, pl. 2, figs. 62 and 63, pl. 45, figs. 1-4; Branson, 1923, p. 110, pl. 17, figs. 8-10, 15, 16; Stainbrook, 1942, pp. 616-617, pl. 89, figs. 19-22. [non: A. vit- tata Nettleroth, 1889, p. 87, pl. 16, figs. 25-32; Savage, 1931, pl. 30, figs. 4-5]. Athyris fultonensis (Swallow), Cleland, 1911, pp. 83-84, pl. 14, figs. 1—4 [non A. fultonensis Savage, 1930, pl. 4, figs. 3—4]. Material examined.—The figured specimens: GSC 122862 to 122864. Additional material includes GSC 122844, 45 unnumbered complete shells, and 110 ven- tral and dorsal valves. Occurrence.—Athyris vittata occurs in all three sam- ples (Table 1, samples 1F—3F) taken in parasequences 1 and 2 in section A of the Thornton Creek Member of the Flume Formation in the Alberta Rocky Moun- tains. It is a highly variable species and 1s widespread in carbonate platform deposits of central and western North America during the late Givetian (lowest occur- rences known from the Middle varcus Subzone) to ear- ly Frasnian (known to range into deposits correlated with Montagne Noire Zone 4). We have also recovered this species in subtidal carbonate lagoonal facies of the upper Flume Formation at the Miette Reef platform, and it is reported by Maurin and Raasch (1972) from the ““Flume Formation” (undifferentiated) in the in- terval of their Assemblage 4 (early Frasnian) in their Wapati Mountain and Kakwa Lake sections. Its occur- rences in the late Givetian and early Frasnian of Man- itoba, Iowa, and Missouri are outlined in the discus- sion of Thornton Creek brachiopod faunas above. Discussion.—The 160 specimens recovered include a complete range of growth stages from small juve- niles to medium sized adults. The Thornton Creek specimens are closest to the Athyris vittata randalia morphotype of Stainbrook (1942, pl. 89, figs. 1—6). The three varieties of A. vittata described by Stain- brook (1942, p. 616) are considered to be phenotypic variants of highly variable populations of one species. Order ATRYPIDA Rzhonsnitskaya, 1960 Family ATRYPIDAE Gill, 1871 Subfamily ATRYPINAE Gill, 1871 Genus PSEUDOATRYPA Copper, 1973 Type species.—Atrypa devoniana Webster, 1921, p. 15 (see illustrations in Fenton and Fenton, 1935). Pseudoatrypa aff. P. gigantea (Webster, 1921) Plate 2, figures 1-13 Atrypa gigantea Webster, 1921, p. 16; Fenton and Fenton, 1935, p. 376; Stainbrook, 1938, p. 233, pl. 30, figs. 5, 13, 17. Atrypa cf. gigantea Webster, Warren and Stelck, 1956, pl. 11, figs. 16-18. Pseudoatrypa sp. cf. P. gigantea (Webster), Norris, in Norris and Uyeno, 1981, pp. 18-19, pl. 7, figs. 28-38. Material examined.—A partial figured dorsal valve GSC 122816, two nearly complete figured adult shells (slightly crushed) GSC 122818 and GSC 122819, and 22 unnumbered fragments of dorsal and ventral valves. Occurrence.—In the Alberta Rocky Mountains Pseudoatrypa sp. aff. P. gigantea (Webster, 1921) oc- curs in the late Givetian Thornton Creek Member of the Flume Formation at its type section in sample 3 (Table 1; Text-fig. 6) as an element of the Eleuthero- komma-Schizophoria Fauna. Similar forms are known from older late Givetian deposits in lowa and younger latest Givetian and early Frasnian deposits in north- eastern Alberta (see below). Discussion.—The same species, or closely similar forms, of Pseudoatrypa are widespread in late Givetian and early Frasnian carbonate platform and basinal de- posits in central and western North America. Pseu- doatrypa gigantea (Webster, 1921) was first described from late Givetian deposits in central and eastern Lowa. Webster’s original types were lost, according to dis- cussion by Fenton and Fenton (1935, p. 376). In his description of P. gigantea, Stainbrook (1938) desig- nated two specimens as hypotypes and mentioned five additional comparative specimens (one lost, remaining material housed at the University of Iowa) from the upper part of the Rapid Member of the Cedar Valley Limestone (now Little Cedar Formation, see Witzke et al., 1989, pp. 229-232) interval of his ““Atrypa wa- terlooensis Zone.’ Stainbrook’s specimens originate from the upper Rapid Member of the Little Cedar For- mation that yields conodonts of the Lower subterminus Fauna (Day, 1992, 1996) and hence those specimens are slightly older than the material illustrated here from the Thornton Creek Member of the Flume For- mation. BULLETIN 369 PLATE 2 3F from section A at GSC Thornton Brachiopods from the Thornton Creek Member of the Flume Formation. All specimens from sam locality, Ancient Wall Reef Platform, Jasper National Park, Alberta, Canada. All specimens 1.5 unless otherwise indicated. Pseudoatrypa aft. P. gigantea (Webster, 1921) 5. Figured specimen. GSC 122818: dorsal, anterior, ventral, posterior, and left-lateral views, respect ely of damaged shell 13. GSC 122816: 6, 13. internal view of dorsal valve showing lobate impressed adductor muscle field, oblique ridges and srooves on floor of sockets, and massive crural bases arising from inner socket ric <3 and *1.5 respectively; 12. external view showing abraded radial ribs 7-11. GS¢ 19: dorsal, ventral, anterior, right-lateral, and posterior views, respectively of relatively complete shell, showing damage to left anterior margin resulting from encrusting epibionts (epibionts not preserved) THORNTON CREEK MEMBER: DAY AND WHALEN 141 Warren and Stelck (1956, pl. 11, figs. 16-18), illus- trated a similar form under the name “‘Atrypa” cf. gi- gantea Webster, from the latest Givetian—early Fras- nian Waterways Formation at McMurray, Alberta. Norris (in Norris and Uyeno, 1981, p. 18) illustrated P. sp. cf. P. gigantea (Webster, 1921) from the Calu- met Member of the Waterways Formation on Birch River and along the Athabasca River near Fort Mc- Murray, in northeastern Alberta. Norris (1963, text- figs. 6 and 8) noted “Atrypa” cf. gigantea Webster from the early Frasnian Calumet and Moberly mem- bers of the Waterways in the Clearwater-Athabasca Rivers outcrop belt. Subfamily VARIATRYPINAE Copper, 1978 Genus DESQUAMATIA Aleskeeva, 1960 Subgenus INDEPENDATRYPA Copper, 1973 Type species.—Atrypa independensis Webster, 1921, p. 15 (see illustrations in Fenton and Fenton, 1935). Desquamatia (Independatrypa)? sp. Plate 1, figures 11, 12 Material examined.—The illustrated specimen GSC 122871, and six unnumbered valve fragments. Occurrence.—This species occurs in the interval of sample 3F in the type section of the Thornton Creek Member at the GSC Thornton Pass locality (Text-figs. 3, 4, 6). Discussion.—The limited material available does not permit a definitive assignment to any described species of Desquamatia (Independatrypa). Suborder DELTHYRIDINA Ivanova, 1972 Superfamily DELTHYRIDOIDEA Phillips, 1841 Family MUCROSPIRIFERIDAE Boucot, 1959 Genus ELEUTHEROKOMMA Crickmay, 1950 Type species.—Eleutherokomma hamiltoni Crick- may, 1950, pp. 220—222, pl. 36, figs. 1-3. See internal features in Crickmay, 1953, pl. 3, figs. 6-9. Eleutherokomma wendtei new species Plate 3, figures 1-17 Diagnosis.—Medium sized Eleutherokomma up to 22 mm in width, with inflated subpyramidal ventral valve with gently concave nearly catacline to apsacline ventral interarea; eight to 15 simple plications per flank on adult shells (shells 13 mm and wider); dorsal and ventral interior with short medial myophragm (dorsal myophragm variably developed: absent or not preserved in 20% of specimens). Description.—Medium sized Eleutherokomma with greatest width at hinge or at mid length (largest ventral valve width of 22 mm), width greater than length (Ta- bles 2 and 3); acute cardinal extremities with very short mucronate extensions (see Plate 3, figures 7—9); subpyramidal ventral valve with greatest width along hinge in juvenile growth stages, in adult shells (width greater than 15 mm) greatest width is anterior of hinge along rounded flanks 50% to 60% of length anterior of cardinal margin. Shell ventribiconvex, in profile, with more inflated ventral valve up to 70% of shell thickness, transversely semicircular in outline in early growth stages (less than 14 mm in width), with great- est width at midlength at rounded lateral margins an- terior of acute lateral cardinal margins in larger adult shells (>14 to 15 mm in width). Shell surface with simple-rounded radial plica on flanks (up to 15 per flank). Medially uniplicate with simple fold and sul- cus. Sulcus broad with nearly flat to slightly concave lateral profile near anterior margin. Medial anterior margin of ventral sulcus extended dorsally to form prominent tongue in large adult shells. Concentric growth lamellae overlap anteriorly as seen in other species of the genus. Preserved micro-ornament con- sists of radial capillae on and parallel to plica and in intervening grooves. Ventral valve with open triangular delthyrium ex- tending from cardinal margin ventrally to just beneath apex of valve; slightly concave interarea nearly verti- cal to slightly apsacline in juvenile shells becoming strongly recurved (apsacline with area inclined up to 60° relative to commissural plane) in some adult shells. Ventral interior features short low myophragm or ridge arising at posterior margin of valve interior in the del- thyrial cavity between and extends up to 50% of valve length, flanked on either side by weakly to moderately impressed adductor muscle scars; bases of dental plates extend anteriorly to form low rimmed margin around muscle scars where muscle scars moderately impressed. Short dental plates, extend anteriorly 10— 15% of valve length, bounding and parallel to margin of delthyrium from posterior margin ventrally approx- imately 70% of shell depth, then diverge laterally be- neath the apex away from margin of delthyrial opening joining floor of ventral valve beneath flanks. Simple short peg-like teeth. Dorsal valve with simple fold averaging 37% of maximum valve width at anterior margin, with broad U-shaped lateral outline. Fold bounded by strong grooves, flanks with simple plica with rounded trans- verse profiles with simple grooves or interspaces, av- eraging nine per flank (range is 8 to 15 in shells greater than 13 mm in width), cardinal margin with extremely short (less than .06 mm) strongly apsacline dorsal in- terarea. Cardinalia in dorsal interior consist of simple ctenophoridium with up to a dozen vertical lamellae, 142 BULLETIN 369 PLATE 3 Brachiopods from the Thornton Creek Member of the Flume Formation. All specimens from sample 3F from section A at GSC Thornton Pass locality, Ancient Wall Reef Platform, Jasper National Park, Alberta, Canada. All specimens 1.5 unless otherwise indicated. I-17. Eleutherokomma wendtei new species: 1—4, 16. GSC 122823 (syntype), 1, 2. upper views of ventral valve, at 4 and 1.5 respectively; 3, 4. anterior views, at 1.5 and 3, respectively; 16. internal view showing dental plates, and medial ventral myophragm 5, 6. GSC 122828 (paratype): dorsal and anterior views of complete adult with rounded profile and outline. 7-9. GSC 122829 (paratype): dorsal, posterior, and ventral views, respectively of large juvenile growth stage O, 13. GSC 122835 (syntype): external and internal views of dorsal valve. Internal view shows low medial myophragm, flanked by impressed adductor scars, sockets, socket ridges, ctenophoridium, and bases of the crus arising from socket plates. 1, 12. GSC 122825 (paratype): ventral and anterior views of ventral valve 4. 15. GSC 122830 (paratype): exterior and internal views, respectively of dorsal valve 7. GSC 122822 (syntype): upper view of ventral valve 18-22. Cyrtina triquetra (Hall, 1858) 8. GSC 122839: Oblique view from posterior of partial ventral valve (showing strong medial septum fused to dental plates to form posterior chamber, delthyrial covering not preserved 9, 22. GSC 122841: ventral and dorsal views, respectively, of complete shell showing external ornament. Ventral view shows trace of ventral medial septum preserved on surface of specimen 20, 21. GSC 122840: ventral and dorsal views, respectively, of a relatively complete small adult shell showing external ornament. 23. Cranaena species. GSC 122845: internal view of damaged adult ventral valve THORNTON CREEK MEMBER: DAY AND WHALEN 143 lamellae rarely preserved in the available material. Ctenophoridium positioned medially on floor of dorsal valve immediately anterior of and below dorsal beak in space between socket plates and crural bases. Sock- ets oriented at approximately 35° relative to cardinal margin, preserved socket plates simple with angular edges between socket and cardinal margin. Short blade-like crura parallel to inner margins of fold, arise from and fused with bases of socket plates on inner valve surface just below commissure of medial cardi- nal margin. Very low medial myophragm extends up to 50% of valve length on floor of valve, some shells with impressed adductor muscle pits flanking my- ophragm near apex of valve interior. Types.—Three syntypes GSC 122822, 122823 122835, the figured paratypes GSC 122825, 122828 to 122830; and 12 unfigured paratypes GSC 122827, 122831 to 122834, 122836 to 122838, 122874 to 122877. Other material examined.—248 unnumbered whole and fragments of dorsal and ventral valves from sam- ple 3F at the type locality. Type stratum and locality.—The type stratum is the 1.5 meter interval of sample 3, type section of the Thornton Creek Member of the Flume Formation at Thornton Pass, in Jasper National Park, Alberta Rocky Mountains (Text-figs. 2, 3, 4, 6; GSC Thornton Pass locality). Occurrence.—Eleutherokomma wendtei is restricted to late Givetian age Thornton Creek Member of the Flume Formation at its type section in the Alberta Rocky Mountains. In western Alberta, it is the domi- nant species of the Eleutherokomma-Schizophoria Fauna of the Thornton Creek Member described above. Discussion.—The material on hand displays well- preserved internal features consistent with the genus as first defined by Crickmay (1950, pp. 219-220). These include a cardinal process consisting of simple ctenophoridium, a low myophragm in the dorsal inte- rior, and a low myophragm and lack of a delthyrial plate in the ventral interior. Thus far, no delthyrial cov- ering (pseudodeltidium or stegidium) is known from any species described from Givetian—middle Frasnian strata of western and central North America. The re- lated genus Mucrospirifer Grabau, 1931, has a well- developed delthyrial covering as shown in illustrations of the type species M. mucronatus in Tillman (1964, pl. 153) and Cowen (1968), and lacks well-developed dental plates. Those features readily distinguish it from Eleutherokomma. The juvenile growth stages of Eleutherokomma wendtei are closely similar to, although proportionally thicker than, adult shells of E. impennis Crickmay, 1950 (see: Crickmay, 1950, pl. 2; Warren and Stelck, 1956, pl. 120; McLaren et al., 1962, pl. 10; Harring- ton, 1971, pl. 4, figs. 12-16 only; and Norris, in Norris and Uyeno, 1983, pls. 7, 8). Eleutherokomma wendtei is easily distinguished from E. impennis by its much larger (up to 22 mm in width) proportionally thicker (greater shell thickness) adult shell, more numerous flank plications, greater range in the angle of inclina- tion of the nearly catacline to apsacline ventral inter- area, and its greatest shell width anterior of the hinge. Nearly all other described species of Eleutherokomma are distinguished from E. wendtei by their less inflated ventral valves, and short and highly recurved concave ventral interareas, with mucronate or extended cardinal margins. Order SPIRIFERINIDA Ivanova, 1972 Suborder CYRTINIDINA Carter and Johnson, 1994 (in Carter et al., 1994) Superfamily CYRTINOIDEA Frederiks, 1912 Family CYRTINIDAE Frederiks, 1912 Genus CYRTINA Davidson, 1858 Type species.—Calceola heteroclita Defrance, 1828, p. 306. Cyrtina triquetra (Hall, 1858) Plate 3, figures 18-22 Cyrtia triquetra Hall, 1858, p. 513 Cyrtina triquetra Meek and Worthen, 1868, p. 436, pl. 13, fig. 4; Hall and Clarke, 1894, pl. 28, figs. 34 and 35; Cyrtina triquetra (Hall) Stainbrook, 1943, pp. 446-447, pl. 22-29. Cyrtina ct. triquetra Hall, Maurin and Raasch, 1972, pl. 9, figs. 5—7. not Cyrtina triquetra Warren and Stelck, 1956, pl. 15, figs. 22—24. Material examined.—The illustrated specimens GSC 122839 tol22841; two unfigured shells GSC 122842 and 122843; six unnumbered whole juvenile and adult shells; and 36 unnumbered fragments of ven- tral valves. Occurrence.—The range of this form in the Give- tian of North America is from the Upper varcus Sub- zone to norrisi Zone. In western and central Canada, this species 1s known from the “Flume” Formation of northeast British Columbia (Maurin and Raasch, 1972), the Thornton Creek Member of the Flume at Ancient Wall in the Alberta Rocky Mountains (this report); and the lower part of the argillaceous lime- stone beds of the Point Wilkins Member of the Souris River Formation of southwestern Manitoba (Norris and Day, in Day et al., 1996, text-fig. 5). In the central United States it is known from its type locality in the Little Cedar Formation in northwestern Illinois and eastern Iowa, and ranges into the Coralville Formation 144 BULLETIN 369 of Iowa and Illinois (Stainbrook, 1943; Day, 1989a, 1992, 1996, 1997). Discussion.—Cyrtina triquetra is widespread in car- bonate and mixed clastic-carbonate platform deposits in central and western North America as outlined above. In northeast British Columbia, this form is il- lustrated from the brachiopod fauna of Assemblage 4 of the Flume Formation by Maurin and Raasch (1972), and was reported by Norris and Day (in Day et al., 1996, fig. 5) from the argillaceous limestone beds of the Point Wilkins Member of the Souris River For- mation. Hall (1858) erected this form based on specimens from Rapid Member of the Litthe Cedar Formation and Cou Falls Member of the Coralville Formation in east- ern Iowa and western Illinois. Other species of Cyrtina known from late Givetian deposits in North America include C. caroline Johnson (1978) and C. umbonata (Hall, 1858). Cyrtina caroline Johnson (1978, p. 131, pl. 8, figs. 1-31), described from the late Givetian of the Great Basin, differs from C. triquetra (Hall, 1858) by its more numerous flank plications and angular si- nus. Cyrtina umbonata (Hall, 1858) from the late Giv- etian of the Iowa Basin differs from C. triquetra by its larger adult shell size, fewer flank plications, highly concave (apsacline to anacline) interarea, and shallow U-shaped ventral sinus. Order TEREBRATULIDA Waagen, 1883 Suborder TEREBRATULIDINA Waagen, 1883 Superfamily DIELASMATATOIDEA Schuchert, 1913 Family CRANAENIDAE Cloud, 1942 Subfamily CRANAENINAE Cloud, 1942 Genus CRANAENA Hall and Clarke, 1893 {=Eunella Hall and Clarke, 1893, and Cranaenella Fenton and Fen- ton, 1924] Type species.—Terebratula romingeri Hall, 1863, p. 48, text-figs. 22-23. Cranaena sp. Plate 3, figure 23 Material examined.—Figured damaged ventral valve of large adult GSC 122845, unfigured small adult shell GSC 122863, one unnumbered juvenile shell, and five unnumbered partial ventral valves. Occurrence.—Cranaena sp. of this study is known only from sample 3F from section A (type section of the Thornton Creek Member) of the Flume Formation at Thornton Pass (GSC Thornton Pass locality). Discussion.—The present material on hand—single juvenile shell, small adult shell (GSC 122863), and poorly preserved fragments of ventral valves (figured specimen GSC _ 122845)—does not permit identifica- tion of the Thornton Creek species or accurate com- parisons with other late Givetian species of Cranaena. The small adult shell is similar in outline and profile to small adult specimens of C. iowensis (Calvin, 1890) and C. sp. cf. C. iowensis known from coeval deposits in eastern Iowa and central Missouri (see species listed in Day, 1996, 1997), and southwestern Manitoba (see fig. 5 of Norris, Day, and Uyeno, in Day er al., 1996), respectively. The partial ventral valve of the large adult (GSC 122845) suggests a maximum size similar to that of C. towensis. 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Sedimentation and stratigraphic architecture of a Middle Devonian (late Givetian) transgressive-regressive carbon- ate-evaporite cycle, Coralville Formation, Iowa area. in Paleozoic Sequence Stratigraphy, Biostratigraphy, and Biogeography: Studies in Honor of J. Granville (“Jess”) Johnson. G. Klapper, M.A. Murphy, and J.A. Talent, eds., Geological Society of America Special Paper 321, pp. 67-88. Witzke, B.J., Bunker, B.J., and Klapper, G. 1983. Devonian stratigraphy in the Quad Cities area, eastern Iowa-northwestern Illinois. i2 Devonian & Pennsylvanian stratigraphy of the Quad-Cities Region Iowa-IIlinois. W.R. Hammer, R.C. Anderson, and D.A. Schroeder, eds., Great Lakes Section of the Society of Economic Paleontologists and Mineralogists, 15" Annual Field Conference Guide- book, pp. 19-64. Witzke, B.J. Bunker, B.J., and Rogers, F.S. 1989. Eifelian through lower Frasnian stratigraphy and deposi- tion in the lowa area, Midcontinent, U.S.A. in Devonian of the World. N.J. McMillan, A.E Embry, and D.J. Glass, eds., Canadian Society of Petroleum Geologists Memoir 14, vol. 1, pp. 221-250. Witzke, B.J. and Heckel, P.H. 1989. Paleoclimatic indicators and inferred Devonian paleolati- tude of Euramerica. in Devonian of the World. N.J. Mc- Millan, A-E Embry, and D.J. Glass, eds., Canadian So- ciety of Petroleum Geologists Memoir 14, vol. 1, pp. 49-66. BEAVERHILL LAKE GROuP, CENTRAL ALBERTA, CANADA: UYENO AND WENDTE CONODONT BIOSTRATIGRAPHY AND PHYSICAL STRATIGRAPHY IN TWO WELLS OF THE BEAVERHILL LAKE GROUP, UPPER MIDDLE TO LOWER UPPER DEVONIAN, CENTRAL ALBERTA, CANADA T. T. UYENO AND J. C. WENDTE Geological Survey of Canada 3303—33" Street N.W. Calgary, Alberta T2L 2A7 CANADA ABSTRACT An integrated study of conodont biostratigraphy with transgressive-regressive sequence stratigraphy has related genetic suc- cessions of the Beaverhill Lake Group over a widespread area of south-central Alberta. The study area spans from the Eastern Shelf in eastern Alberta through an intervening Central Alberta Basin, to the Western Shelf in western Alberta. This paper primarily reports on the conodont biostratigraphy of basinal successions (Waterways Formation) from two wells, 32 km apart, near the Western Shelf, within a sequence-stratigraphic framework. In the area of the two wells in central Alberta, the Waterways Formation consists of up to approximately 150 m of interstratified basinal limestones and calcareous shales. The entire Waterways succession is divided into nine genetic units, which have been correlated throughout the basin. These genetic successions are assignable to six conodont zones: in ascending order, the Upper subterminus Fauna (approximately equivalent to the Upper disparilis Subzone), the norrisi Zone, and Montagne Noire (MN) zones | to 4. This suggests that sedimentation was continuous across the Givetian-Frasnian (Middle-Late Devonian) boundary. The standard marker for the base of MN Zone 4, Palmatolepis transitans, makes a late entry within that zone. The base of MN 4 was determined by the first occurrence of Ancyrodella postbinodosa new species, a species that has been demonstrated to be restricted to that zone through graphic correlation (Klapper, pers. commun., 2000). Other new species introduced here include Mesotaxis keithi, Palmatolepis paradisparilis, and Polygnathus tedi. The correlations made independently from physical sequence stratigraphy and conodont biostratigraphy parallel one another and thus corroborate each other. INTRODUCTION The Beaverhill Lake Group in the subsurface of south-central Alberta consists of limestones, dolo- stones, and calcareous shales, up to over 200 m thick. These strata overlie coastal plain and marginal marine shales, dolostones, and limestones of the Watt Moun- tain Formation and are overlain by either platform car- bonates (Cooking Lake and Leduc formations) or ba- sinal shales and limestones (Duvernay Formation) of the Woodbend Group (Text-fig. 1). Beaverhill Lake strata were examined throughout an extensive area in south-central Alberta. The area of investigation extends from the Alberta-Saskatchewan boundary west to the Cordilleran thrust belt or the Sixth Meridian and from Township 24 north through Township 71 (Text-fig. 2). Within this area, the Beav- erhill Lake Group is divided into two formations (Text-fig. 1). The Swan Hills Formation includes shal- low-marine limestones and dolostones that occur in the western part of the study area. These carbonates were deposited on areally extensive carbonate platforms, and on both younger, backstepped carbonate platforms, hereinafter referred to as banks, and areally restricted, isolated reefs (Text-fig. 2). The Waterways Formation GSC Contribution No. 2001019 denotes basinal limestones and calcareous shales de- posited throughout most of the study area, but also incorporates limestones and dolostones deposited on areally extensive carbonate platforms and _ isolated reefs in the eastern part of the study area. SCOPE OF PAPER This paper focuses on the results of an integrated study of the conodont biostratigraphy, physical stratig- raphy, and sedimentology of the Beaverhill Lake Group from two wells in the northwestern part of the area of investigation (Text-fig. 2). The Pan American Home Archie well (4-1-66-8WS) (hereafter called the Archie well) lies just basinward of the Swan Hills plat- form and contains a continuous core through the entire basinal Waterways succession. The Imperial Forestry well (16-7-64-10W5) (hereafter called the Forestry well) occurs along the northeastern flank of the iso- lated Judy Creek reef complex. A core at this well penetrates the entire Waterways succession at this lo- cation, including both distal foreslope deposits shed from the reef and overlying basinal limestones and cal- careous shales. Both cores were described in detail and systematically and extensively sampled for conodonts. This paper also incorporates and summarizes as- pects of both the physical and conodont biostratigra- Nn ie) BULLETIN 369 GROUP FORMATION W E \ IRETON | COOKING WOODBEND LEDUC | Ae | DUVERNAY | —* x z | | en BEAVERHILL foe) LAKE ees Tlie oS, a cree ues SWAN WATERWAYS WATERWAYS g HILLS zs Set | Wx ——— | = v -- Vv ELK = = POINT L = = es MOUNTAIN —— = Basinal limestone-shale Shallow-marine carbonate _~_~_} Coastal plain to marginal marine shale-carbonate Text-figure 1.—Lithostratigraphy of the Elk Point, Beaverhill Lake, and Woodbend Groups of south-central Alberta. W6 | W5 TWP 71 W5 | W4 W4 | W3 4 —— awe7 FACIES LEGEND ARCHIE: 75 = =, Carbonate banks /reefs WELL 7 ime Shed FORESTRY |. Carbonate platforms Ce — "WELL: 5 eaiece, GREED. Cerne ore [| Central Alberta Basin ; otf: JUDY CREEK’. J TWP 60 7 SWAN HILLS fg REEF [a See ane . T I : sieel 1 It e sell ce Sag TWP 50-525 a Sa, aaa SEE Ore ie # SEE ea See CL we 50 oa ee gitbck es ccgran tra acicereas : ai i=l 4, XN. SWAN HILLS ::-:.G eee Ng PLATFORMS 2 eee S eee ee eee ae = LL ead L see aE W6 W5 a —~ Twe 40 OED met oe rie we 30 : I I ; ! i it ar : | Ti ce as ay al T TWP 24 ws! w4 wa | w3 Text-figure 2—Map showing Beaverhill Lake domains in subsurface of south-central Alberta. The Pan American Home Archie 4-1-66- 8W5 and Imperial Forestry 16-7-64-10W5 wells occur in the vicinity of the Judy Creek reef complex in the northwestern part of the map area, The transects at Townships 50-52 and from the Archie well to the Judy Creek reef complex correspond to the position of cross-sections on Text-figures 4 and 5, respectively. A small index map shows the location of the study area. BEAVERHILL LAKE GROUP, CENTRAL ALBERTA, CANADA: UYENO AND WENDTE 153 phy from wells throughout the entire area of investi- gation. The data base includes approximately 1300 wells, whose depositional cycles were correlated throughout a grid of wireline log cross-sections. Cores from approximately 150 of these wells were described, enabling a detailed interpretation of the depositional facies and depositional sequences. Cores from 49 of these wells were sampled for conodont biostratigraphy. This synthesis provides a more regional context to the physical and conodont biostratigraphy for the Archie and Forestry wells. ACKNOWLEDGMENTS We thank David Sargent who prepared the text-fig- ures, and amiably made several revisions of them. We also thank Jenny Wong who made SEM graphic files of the conodonts, and Karen Paull who prepared the many conodont samples and also demonstrated to TTU the use of a graphic program in preparation of illus- trative plates. In the latter demonstration, further as- sistance was generously provided by Sandy Mc- Cracken and Godfrey Nowlan. All personnel cited are with the Geological Survey of Canada, Calgary. DEPOSITIONAL SETTING Beaverhill Lake strata comprise three depositional domains (Text-fig. 2). A Western Shelf consists of a succession up to 150 m thick of shallow-marine lime- stones and dolostones of the Swan Hills Formation. These carbonates were deposited on the carbonate plat- forms, banks, and isolated reefs situated along the east- ern flank of the slowly subsiding Western Alberta Arch. A pronounced embayment at a latitude of ap- proximately Township 40 separates the Western Shelf into northern and southern sub-domains. An Eastern Shelf complex occurs in the eastern half of the area of investigation. The position of the margin of this shelf shifts during the deposition of Beaverhill Lake strata. During transgressive episodes the margin retreats or backsteps to the southeast. During regres- sive episodes the shelf margin progrades to the north- west. The position of the shelf margin depicted on Text-figure 2 corresponds to its most regressive, bas- inward position. For geographical reference the area of the shelf shown on Text-figure 2 is termed the Eastern Shelf Domain. As a result of these transgressive and regressive episodes, boreholes throughout most of the Eastern Shelf Domain encounter an interbedded suc- cession of basinal limestones or calcareous shales and shallow-marine limestones and dolostones, deposited mainly on widespread carbonate platforms and to a lesser degree on isolated carbonate reefs. This Eastern Shelf Domain succession thickens to the northeast, away from the positive Western Alberta Arch, attain- ing a maximum thickness of approximately 240 m. The Central Alberta Basin occurs between the east- ern and western shelves. Deposits in the basin consist entirely of deep-water calcareous shales and lime- stones. These deposits vary in thickness from 75 to 210 m. PHYSICAL STRATIGRAPHY EASTERN SHELF AND CENTRAL ALBERTA BASIN Beaverhill Lake strata on the Eastern Shelf and in the Central Alberta Basin consist of nine transgressive- regressive (T-R) cycles (termed A to H, with A sub- divided into lower and upper parts). T-R cycle bound- aries were determined from both core and wireline log examination. Text-figure 3 shows the gamma-ray log and sonic log signatures of these T-R cycles from a well (6-35-46-15W4) on the Eastern Shelf Domain. T- R cycle boundaries correspond to the position, within a given interval, that marks the change from progres- sively shallower-water facies to progressively deeper- water facies. This position is marked by an increase in argillaceous content. On wireline logs this level cor- responds to an increase in the radiation count on gam- ma-ray logs and to decreased acoustic velocities on sonic logs. In either basinal successions or in succes- sions that grade from basinal facies up into shallow- water facies, T-R cycles have a dominantly shoaling- upward aspect. This aspect corresponds to decreasing argillaceous content and is recorded by decreasing ra- diation on the gamma-ray logs and by increased acous- tic velocities on the sonic logs. In these T-R cycles, such as cycle B, the transgressive part of the succes- sion is either absent or thin. Some T-R cycles, how- ever, may have either a significant transgressive basal portion (cycle G) or have an overall transgressive as- pect (Upper A cycle). On the Eastern Shelf Domain, it is important to rec- ognize that the top of the Beaverhill Lake Group (top of succession H) is not a T-R cycle contact. Instead, it is a facies contact and, as illustrated on Text-figure 3, marks the position in a shoaling-upward cycle where shallower-water carbonate facies of the Cooking Lake Formation prograde over deeper-water, argillaceous fa- cies of succession H. Correlation of T-R cycle boundaries allows recog- nition of the change from regression to transgression. The cross-section on Text-figure 4 shows the correla- tion of the T-R cycle boundaries and the disposition of depositional facies within these cycles on an east- west transect across the basin, at the latitude of Town- ship 50-52. The cross-section also shows the lower successions of the overlying Woodbend Group. On the eastern side of the basin, shallow-water lithofacies are 154 BULLETIN 369 i SONIC MAJOR (Increasing radioactivity) (Increasing velocity) T-R CYCLES/ eens SUBDIVISIONS COOKING LAKE FM. % als H U G L 1350 m v 2 YY L v v a a gs fF 1400 m n [e) x Lo} : a U = x= Cc w + 1450 m hy a x 1 = 1500 it LOWER fal ee LONE ——t Vv WATT MOUNTAIN — FORMATION =e 1550 m PRAIRIE : a EVAPORITE FM. Ls | FACIES LEGEND Shallow-marine carbonate Basinal limestone —= Basinal shale “| Coastal Plain argillaceous : dolostone Vv Vv VV i, WAN] Anhyarite Halite Text-figure 3 Gamma-ray and sonic log signatures of the nine T-R cycles of the Beaverhill Lake Group and their lithofacies. These cycles are combined into two major T-R cycles (1 and 2), each of which is divided into two subdivisions (L and U). Well 6-35-46-15W4, Eastern Shelf Domain. Depths correspond to log depths. See Text-fig. 2 for location. limited to the Eastern Shelf Domain, east of the Fifth Meridian. Basinal, deeper-water facies form clino- forms to the west and distally onlap the Swan Hills platform-bank complex on the Western Shelf. The T-R cycles on the Eastern Shelf and in the Cen- tral Alberta Basin are split into two major T-R suc- cessions. Each of these T-R cycles, in turn, can be subdivided into two T-R cycle subdivisions. The major T-R cycles and their subdivisions are marked on the gamma-ray log and on the sonic log on Text-figure 3 as well as on the cross-section on Text-figure 4. The lower T-R succession | extends from the base of the group to the top of cycle D. The transgressive phase of this succession extends up into the calcareous shales in the basal part of cycle B. The regressive phase culminates in the progradation of shallow-water BEAVERHILL LAKE GROUP, CENTRAL ALBERTA, CANADA: UYENO AND WENDTE l Nn Nn W E CENTRAL MAJOR WESTERN ALBERTA Lepyc SUB-CRETACEOUS —_T-R CYCLES/ SHELF BASIN EASTERN SHELF DOMAIN -m. Cee rec tlh SUBDIVISIONS 300 m— fan DUVERNAY FM. El 300 m FM. Bese UPPER F MIDDLE i a EGORC TREE [Nees ae om oe KING LAKE ae 240m— hy FM. LOWER = 240m ._ U 180 m— 2 1! 120m LAKE GROUP 120m y 1 60m 60 m L LOWER A DATUM 18W5 WATT MOUNTAIN FM. W4!|W3 FACIES LEGEND fees] Shallow-marine carbonate Basinal limestone or interbedded limestone-shale —_-_-} Basinal shale Kilometres 0 48 96 4 Text-figure 4.—Stratigraphic cross-section of the Beaverhill Lake Group showing the correlation of T-R cycles and the disposition of depositional facies, at a latitude of Township 50-52. The major T-R cycles and their subdivisions are labeled at the right end. Vertical ticks at the base of the cross-section correspond to the position of wells. See Text-fig. 2 for location of the transect. platform carbonates of cycles C and D to approxi- mately the Fifth Meridian. T-R succession 1 can be split into two T-R cycle subdivisions (1L and 1U) at the top of cycle B. The onset of the T-R subdivision 1B is not marked by a significant shift in facies at the top of the cycle B plat- form, but by the deposition of a thick shale succession in the basin. The upper T-R succession 2 extends from the top of cycle D to the top of cycle H in the Central Alberta Basin. The top of cycle H in the basin corresponds to the T-R cycle boundary that separates the Beaverhill Lake and Woodbend Group successions. Upslope, it correlates to the top of the lower Cooking Lake suc- cession on Text-figure 4 (base of cycle 2, middle mem- ber of the Cooking Lake Formation of Wendte, 1994). T-R succession 2 includes platform and isolated reefal carbonates of cycles E and F (cycle E platform facies occur south of the transect of the cross-section on Text-figure 4) and the argillaceous limestones and calcareous shales of cycles G and H. The position of maximum transgression occurs near the middle of cy- cle G. Calcareous shales in the upper part of cycle G and in cycle H sigmoidally prograde to the west, al- lowing for the outbuilding of the lower Cooking Lake platform succession to approximately the Fifth Merid- ian. The top of cycle F marks the division between the lower and upper T-R subdivisions (2L and 2U). 156 BULLETIN 369 JUDY <— 8.3KM——» FORESTRY 2 ——— SS NIE BEAVERHILL LAKE FACIES fed Shallow-marine limestone *:4 Foreslope limestone Basinal limestone-shale = g SS c R BS SS —- norrisi LEGEND Cycle boundaries Base of conodont zones First and/or only occurrences of 1. Ozarkodina sannemanni 2. Polygnathus tedi n. sp. 3. Mesotaxis bogoslouskyt 4. Palmatolepis transitans, Pal. paradisparilis n. sp Text-figure 5.—Stratigraphic cross-section of the Beaverhill Lake Group from the Pan American Home Archie 4-1-66-8W5 well into the Judy Creek reef complex (well 4-35-63-11W5). T-R cycle boundaries correspond to the base of radioactive intervals on the gamma ray logs. The cross-section illustrates the parallelism of the T-R cycle and conodont zone boundaries. See Text-fig. 2 for location of the transect. The bases of conodont zones, norrisi, and MN | through MN 4, are marked. The numbers | through 4 mark the only and/or the first occurrences, of the cited conodont species. WESTERN SHELF Swan Hills carbonates on the Western Shelf consist of cyclic repetitions of shallow-marine limestones and dolostones. These carbonate successions lack the ar- gillaceous limestones and calcareous shales that typify the basal portion of T-R cycles on the Eastern Shelf and in the Central Alberta Basin. As a result, cycle boundaries on the Western Shelf have no wireline-log signature and can only be identified by the examina- tion of cores. Therefore, the cycle architecture of Swan Hills carbonates can only be discerned in areas with good well and core control. Also, lacking the log sig- nature of T-R cycles on the Eastern Shelf Domain, the T-R cycle stratigraphy of the Western Shelf is inde- pendent of that on the Eastern Shelf Domain. A synthesis of the T-R cycle stratigraphy of Swan Hills carbonates in the vicinity of the isolated Judy Creek reef complex is presented on the cross-section on Text-figure 5, along a transect from the Archie well southwest through the Forestry well into the Judy Creek reef complex (well 4-35-63-11W5). The T-R cy- cle stratigraphy of Swan Hills carbonates is a summary based on previous investigations of the Judy Creek reef complex (Wendte, 1992, and Wendte and Muir, 1995) as well as aspects from this regional study. The Swan Hills Formation in the vicinity of the Judy Creek reef complex consists of four T-R cycles of growth, each with component sub-cycles, as de- scribed below. (1) A widespread lower platform stage with the po- sition of its margin depicted on Text-figure 2. Stra- tal relationships and conodont biostratigraphy sug- gest that this stage is coeval with the Lower A T- R cycle. BEAVERHILL LAKE GROUP, CENTRAL ALBERTA, CANADA: UYENO AND WENDTE Si7 (2) A progressively more areally-restricted, upper platform stage. (3) A rimmed reef complex stage with a peripheral reef rim and an interior lagoon (not illustrated on Text-fig. 5). The basal portion of this stage marks the change from transgression to progradation (re- gression) of the reef out over a previously drowned platform step. The top of this stage cor- responds to a widespread subaerial unconformity (Wendte and Muir, 1995), termed R4 because it caps the top of the fourth reef cycle. Distinctive aspects of this unconformity have provided a basis for its widespread correlation, including to the Eastern Shelf. R4 corresponds to a level approxi- mately at the middle of cycle C bankward of the underlying cycle B platform margin (Text-fig. 4). The position of the margin of isolated reefs and coeval banks on Text-figure 2 corresponds to an initial phase of this stage. (4) An upper ramp-bounded shoal stage on the isolat- ed reefs. The top of this stage is time-diachronous. Cycles of growth younger than that represented at the 4-35-63-11W5 well are present elsewhere on the Judy Creek reef and other isolated Swan Hills reefs, as well as on the Swan Hills banks. CORRELATION OF WATERWAYS SUCCESSIONS IN THE PAN AMERICAN HOME ARCHIE AND IMPERIAL FORESTRY WELLS The Archie and Forestry wells occur on the west side of the Central Alberta Basin (Text-fig. 2). The location of these wells is analogous to a distal position on the basinal clinoforms of the Waterways Formation on the regional cross-section on Text-figure 4. The tops of T-R cycles A through H occur at the base of radioactive, argillaceous successions at the Ar- chie well on the northeast end of the cross-section on Text-figure 5. These T-R cycle boundaries clinoform to the southwest, away from the position of the Archie well. The tops of cycles A and B onlap the flanks of the Lower and Upper Swan Hills platforms, respec- tively, northeast of the position of the Forestry well. The tops of cycles C and D correlate up into foreslope successions of the Forestry well before onlapping the flanks of the Judy Creek reef complex. These T-R cy- cle boundaries equate to positions in the ramp-bound- ed shoal above R4 at Judy Creek. The tops of cycles E and F correlate to analogous positions in the Forestry well before onlapping against the flank of the Judy Creek reef complex. The tops of cycles G and H (top of Beaverhill Lake Group) cor- relate to analogous positions in the Forestry well and to the base of Waterways successions in the Imperial Judy Creek 4-35-63-11W5 well that overlie the Swan Hills Formation. The close relationship between physical stratigraphy and conodont biostratigraphy is demonstrated on Text- figure 5. The positions of the base of the norrisi Zone and of MN zones | to 4 are shown for the Archie and Forestry wells. The biostratigraphic and T-R cycle boundaries are remarkably parallel. This close rela- tionship is reinforced by correlations of the wells based on the single occurrences of (1) Ozarkodina san- nemanni in MN Zone 2 and of (2) Polygnathus tedi in MN Zone 3, and on the lowest occurrences of (3) Mesotaxis bogoslovskyi and of (4) Palmatolepis para- disparilis and Palmatolepis transitans in MN Zone 4. These positions are marked on Text-figure 5. In the Archie well, the base of the norrisi Zone oc- curs a thin interval (19—19.7 ft; 5.8-6.0 m) above the top of cycle A. Based on a more regional study, how- ever, this is considered to be a late entry for this zone, as elsewhere the base of the norrisi Zone is found between Lower A cycle and Upper A cycle (Text- fig. 6). In the Archie well, the base of MN Zone | occurs about mid-way within the interval of cycle B. This relationship is found in the more regional coverage as well. The bases of MN Zones 2 and 3 are within cycle C in the Archie well, with Zone 3 close to the top of cycle C interval. In the Forestry well, the bases of both zones are found between the top of cycle C and the top of the Swan Hills Platform, and again with Zone 3 close to the cycle top. These relative positions of the bases of Zones 2 and 3 are also found in our more regional study. The base of MN Zone 4 is located high up within cycle E in both wells. The base of MN Zone 5 is not found in the successions in these wells, but based on our regional coverage, it may occur extremely high in the Beaverhill Lake Group and certainly does so in the basal part of the overlying Duvernay Formation. CORRELATION OF THE T-R CYCLES WITH CONODONT ZONES Text-figure 6 shows the relationship between the co- nodont zones, depositional cycles, Euramerican De- vonian T-R cycles (Johnson et al., 1985; Johnson and Klapper, 1992; Day et al., 1996), and the shift of ba- sinal facies of the Beaverhill Lake Group in the Al- berta Basin. The spacing of the conodont zones is based on values provided by Klapper (1997) from his work on the Frasnian Composite Standard. As noted above, the Waterways Formation consists of two megacycles, with the lower T-R succession | ranging from the onset of cycle A to the top of cycle D. The upper T-R succession 2 ranges from the base 158 BULLETIN 369 AGE CONODONT DEPOSITIONAL EURAMERICAN SHIFT OF MAJOR ZONES CYCLES DEVONIAN BASINAL FACIES T-R CYCLES/ T-R CYCLES SUBDIVISIONS MN 5 BASIN LAND COOKING LAKE FM ———-—-—-—--—- —> IIc Se H U MN 4 G S 2 || a-2 coterie - = WW "Lower subserminus WATT MOUNTAIN FM Fauna Text-figure 6.—A summary of the Beaverhill Lake Group from south-central Alberta, showing its conodont zones, depositional cycles, Euramerican Devonian T-R cycles, shift of basinal facies, and major T-R cycles and subdivisions. Conodont zones are after Bunker and Klapper (1984), Witzke er al. (1985), Klapper and Johnson (in Johnson, 1990), and Klapper (1989). Devonian T-R cycles are after Johnson er ai. (1985), Johnson and Klapper (1992), and Day er al. (1996). Spacing of conodont zones is based on values in Klapper (1997). of cycle E to the top of cycle H. The start of succession 1 coincides with the base of the Upper subterminus Fauna, and is at the start of cycle Hla-2. A major trans- gression preceding the Lowermost asymmetricus Zone =norrisi Zone) was suggested earlier by Talent and Yolkin (1987) for the Canning Basin, Western Austra- lia, and for southern West Siberia. A fourth order cy- cle, labelled 3B, was suggested to start in the Late disparilis Zone (=Upper subterminus Fauna) during the Timan Horizon in West Bashkortostan (Yunusov et al., 1997). This may be an equivalent of cycle Ila- 2. Racki (1993, 1997) discussed the global significance of this post-Stringocephalus transgression, and the presence of the transgression at or near the norrisi Zone in western New York State was discussed by Kirchgasser et al. (1997). The peak of the lower suc- cession | occurs in the lower part of cycle B, which occurs in the upper part of the norrisi Zone. Elsewhere, the start of T-R cycle Ha-2 is present at the base of the Argillaceous limestone of the Point Wilkins Member of the Souris River Formation in cen- tral and southern Manitoba, at the base of the Amco Member of the Slave Point Formation at Great Slave Lake, District of Mackenzie, Northwest Territories, and at the base of the Allochthonous Beds in the Pow- ell Creek area in District of Mackenzie, western North- west Territories (Uyeno, 1998). T-R cycle Ilb-1 (Ib of Johnson et al., 1985) is placed at the base of the norrisi Zone, and in the Wa- terways sequence occurs at the base of Upper A cycle. In terms of the Waterways Formation nomenclature, this is at the base of the Firebag Member (Uyeno, 1974) or the base of the Peace Point Member (Uyeno in Norris and Uyeno, 1983), in Alberta. In central and southern Manitoba it coincides with the base of the Micritic limestone of the Point Wilkins Member of the Souris River Formation, and in central and eastern Iowa with the base of the Lithograph City Formation (Day et al., 1996). The start of the upper T-R succession 2 occurs at mid-way of MN Zone 3, and coincides with the base of T-R cycle II[b-2. This cycle represents an intra-IIb cycle deepening event (Day er al., 1996). It is also observed in the Lithograph City Formation, within the Andalusia and Idlewild members, in central and east- ern Iowa. In central and southern Manitoba, this event may occur at the base of the Dolomitic limestone of the Point Wilkins Member, Souris River Formation (Day er al., 1996). The maximum transgression of the upper T-R suc- cession 2 is in cycle G, and lies within MN Zone 4. As noted above, the top of the upper megacycle is at the top of cycle H, and correlates to the top of the lower Cooking Lake succession. This level is in MN BEAVERHILL LAKE GRouP, CENTRAL ALBERTA, CANADA: UYENO AND WENDTE 159 Zone 5 (=Palmatolepis punctata Zone) (Klapper, 1989, 1997; Klapper and Becker, 1999). It coincides with the start of T-R cycle IIc, the beginning of the next major deepening event, and the deposition of the Woodbend Group. This cycle has been recognized over a large area (Johnson er al., 1985; Racki, 1993, 1997: Racki and Bultynck, 1993; among others). CONODONTS CONODONT FAUNA The studied conodont fauna is generally well pre- served and has color alteration index (CAI) of 2 (Ep- stein et al., 1977). The Archie well was sampled at 75 intervals, with each sample averaging 448 g, whereas the 51 Forestry well samples averaged 702 g. The sampled intervals are shown on Text-figures 7 and 8, with listings of selected species only. Of some interest is the concentration of conodonts in allochthonous carbonate sands in the foreslope suc- cession in the Forestry well, from samples number 5 through 13 (interval from 8564.5 ft, 2610.5 m_ to 8624.5 ft, 2628.7 m). The conodont animals may have inhabited a more proximal foreslope environment, and were concentrated when the sand was episodically shed down the reef foreslope and deposited in and around the well-site. CONODONT BIOSTRATIGRAPHY Five, and possibly six, conodont zones are recog- nized in the Beaverhill Lake Group as represented in the two wells. In ascending order, they are the Upper subterminus Fauna, the norrisi Zone, and MN (Mon- tagne Noire) zones | to 4. The first interval is tenta- tively recognized in the lowest parts of the Archie well, and is succeeded by the norrisi Zone in the same well. Zone MNI may possibly be present in the lowest parts of the Forestry well. The higher zones are present in both wells. In the following discussion, refer to Text-figures 7 and 8. It should be noted that the Archie well was independently sampled by McLean and Klap- per (1998), and they recognized exactly the same zonal succession. The history of the subterminus Fauna was succinct- ly summarized by Rogers (1998), so suffice it to say here that Bunker and Klapper (1984) and Witzke er al. (1985) had proposed the subterminus Fauna as the shallow-water carbonate shelf equivalent of the dis- parilis Zone of the standard conodont zonation. How- ever, the exact relationship of the subterminus Fauna to the standard zonation was found to be not entirely clear in a study of the Little Cedar and lower Coral- ville formations of Iowa, by Rogers (1998). The re- fined definition of the fauna, as subsequently proposed by Witzke er al. (1989), is inapplicable to the Beav- erhill Lake collection in these wells. The Upper sub- terminus Fauna has been recognized, however, in some wells included in the overall study, of which this is a part (see Wendte et al., 1995). In the Archie well, the lowest interval of 2313.0 to 2320.7 m, below the first occurrence of Pandorinellina insita (Stauffer), is possibly assignable to the norrisi Zone (see below). This is based on our more regional correlations, where the base of the norrisi Zone occurs much lower. The following species that appear in this interval and continue on higher include Polygnathus angustidiscus, P. xylus xylus, P. dubius, P. alatus, and Icriodus subterminus. The norrisi Zone, proposed by Klapper and Johnson (in Johnson, 1990), is the youngest Middle Devonian conodont zone. This zonal interval was previously re- ferred to the Lowermost asymmetricus Zone of Ziegler (1971) (Klapper and Johnson [ibid.]). Although the en- try of Skeletognathus norrisi marks the base of the zone, in its absence the zonal base is approximated with the entry of Pandorinellina insita. The zone is recognized in the Archie well, within the interval of 2291.8 to 2310.1 m. Herein, S. norrisi was recovered only from an interval assigned to MN Zone 2 in the Forestry well. That this species ranges as high as MN Zone 2 has been demonstrated by means of graphic correlation by Klapper (1997). The Frasnian Stage of the Upper Devonian was di- vided by Klapper (1989) into 13 conodont zones at the Montagne Noire in southern France. Of these, the low- est four zones, MN zones | to 4, are recognized in the Beaverhill Lake sequence. The interval of MN zones 1 to 4 was previously referred to the Lower asymme- tricus Zone of Ziegler (1971). It should also be noted that the interval, including the norrisi Zone, and MN zones | to 3, was placed in the falsiovalis Zone by Sandberg er al. (1989) (Klapper and Johnson in John- son, 1990). The base and the top of MN Zone | are at the first appearances of the early and late forms of Ancyrodella rotundiloba (Klapper, 1985), respectively. In the Ar- chie well, MN Zone 1 occurs in the interval of 2253.2 to 2291.3 m, and may be present in the lowest parts of the Forestry well, in the interval of 2630.1 to 2634.1 m. The only occurrence of A. binodosa is within MN Zone | in the Archie well. Polygnathus incompletus makes its first appearance within this zone and contin- ues up to MN Zone 2, also in the Archie well. MN Zone 2 has its base and top at the first appear- ances of the late form of Ancyrodella rotundiloba and A. rugosa, respectively (Klapper, 1989). In the Archie well, it is in the interval of 2236.3 to 2249.1 m, and in the Forestry well, 2622.3 to 2629.7 m. The only 160 BULLETIN 369 Ancyrodella rugosa Ancyrodella alata Pol. cf. P. decorosus Ancyrodella triangulata Anc. postbinodosa Ancyrodella africana |Meso. bogoslovskyi Anc. rotundiloba early Polygnathus pennatus interval (m) Pol. angustidiscus Pol. xylus xylus Polygnathus alatus >|Polygnathus dubius Pandorinellina insita Ike Pol. incompletus Ancyrodella binodosa Anc, rotundiloba late Ozark. sannemanni |lcriodus expansus Ancyrodella recta Polygnathus tedi Ozarkodina brevis > |Mesotaxis ovalis Conodont zones Cycles =i 7103.0-7104.5 |2165.0-2165.5 74|7104.5-7107.5 |2165.5-2166.4 73|7113.0-7114.5 |2168.0-2168.5 72|7122.0-7125.5 2170.8-2171.9| 71|7133.5-7136.0 |2174.3-2175.1 x x 7142.6-7145.1 |2177.1-2177.8 7148.5-7150.8 |2178.9-2179.6 ? 7161 .3-7163.5 |2182.7-2183.4 x 67 |7163.8-7166.3 |2183.5-2184.3 66|7169.5-7171.0 |2185.3-2185.7 2: 65|7176.0-7178.0 |2187.2-2187.9 64|7180.0-7183.0 |2188.5-2189.4 63|7184.0-7186.5 |2189.7-2190.4 x ? 62|7202.0-7206.0 |2195.2-2196.4 x 61|7212.3-7214 3 |2198 3-2198.9 | il |x x 60 [7218.3-7220.3 2200.1-2200.7 X|X x x _|/criodus subterminus <|Meso. asymmetrica ><|Pal. paradisparilis >| Pol. cf. P. webbi >|Palmatolepis transitans o{|Sample No interval (ft) | |_| xlx[s Pad ~ | [ 4 We a 2 ) MN 4 | KK) 59|7228.5-7230.5 |2203.2-2203.9| x] |? | x|x 58|7232.3-7233.3 |2204.4-2204.7| X 57 |7235.5-7237.5 |2205.4-2206.0 56 [7239 5-7241.0 |2206.6-2207.1 ? 7243.5-7245.5 [2207 8-2208.4 lal [2?T [x 7248.5-7250.5 |2209.3-2210.0 x[x 7253.5-7255.5 |2210.9-2211.5 x 7256.0-7258.0 (2211.6-2212.2 eel 1|7262.5-7264.5 |2213.6-2214 2 x 50|7270.5-7271.5 |2216.0-2216.4 | 49|7278.3-7279.8 |2218.4-2218.9| X 48/7281 .5-7284.0 |2219.4-2220.2| X 47 |7286.0-7288.0 |2220.8-2221.4 aE 46 |7291.0-7293.3 |2222.3-2223.0 [x 45|7298.0-7299.8 |2224.4-2225.0 x 44|7303.0-7305.0 |2226.0-2226.6 x 43|7316.5-7318.5 |2230.1-2230.7 aaa x if 42|7323.0-7325.0 |2232.1-2232.7 x |X X[ x] x 1|7333.0-7334.5 |2235.1-2235.6 | ct iG x 40|7337.0-7339.0 |2236.3-2236.9| X cf |X| X x|x 39|7346.5-7348.5 |2239.2-2239.8| | X 38|7351.0-7352.5 |2240.6-2241.0 Xi OGIEX 37|7357.0-7359.5 |2242.4-2243.2 36 |7363.5-7365.0 |2244.4-2244.9| | X x 35|7371.5-7373.5 |2246.8-2047.4| | [| X 34|7377.5-7379.0 |2248.7-2249.1 31 |7392.5-7394.5 |2253 2-2253.8 30|7396.5-7398.5 |2254.5-2255.1| | X| xX 28|7416.8-7418.0 |2260.6-2261.0 27|7420.3-7422.8 |2261.7-2262.5 x 26|7429.8-7431.5 |2264.6-2265.1| | X 24|7444.5-7446.0 |2269.1-2269.5 23/7454.0-7455.5 |2272.0-2272.4 x 22|7460.0-7461.5 |2273.8-2274.3 21 |7462.3-7464.0 |2274 .5-2275.0 20|7472.0-7473.5 |2277.5-2277.9 19|7483.0-7484.8 |2280.8-2281.4| | 2 | 18|7488.0-7489.5 |2282.3-2282.8 17|7499.0-7500.5 [2285.7-2286.2 16|7509.0-7510.5 |2288.7-2289.2| | 15|7516.0-7517.5 |2290.9-2291.3 x 14|7519.0-7520.5 [2291 8-2292.2 13|7531.0-7532.5 |2295.4-2295.9 11|7553.0-7554.0 |2302.2-2302.5 10|7566.0-7567.5 |2306.1-2306.6 9 |7576.5-7577.5 |2309 .3-2309.6 x 8 |7578.3-7579.0 |2309.9-2310.1 x 6 |7588.5-7590.0 |2313.0-2313.4 5 |7594.0-7595.5 [2314 7-2315.1 4 3 2 MN 3 | <)> | >< if |: I <| ><) xX) < = Pad x x< MN 2 |X| ><] <| | | | xX] xX x< Ie MN 1 | >< | ><] >< | OK | OK | OK | | OK x x x = | x 4 = x x|=|x x x + | B =< Sibel norrisi | >< | KK] x {7598 5-7599.5 |2316.0-2316.3 7602.3-7603.5 |2317.2-2317.5 7613.0-7614.0 *|><| >< >< (et x 2320.4-2320.7 Text-figure 7—Distribution of conodonts in the Beaverhill Lake Group in the Pan American Home Archie 4-1-66-8W5 well. Anc. Ancyrodella, Meso. = Mesotaxis, Ozark. = Ozarkodina, Pal. = Palmatolepis, Pol. = Polygnathus. SWP = Swan Hills Platform, D. Fm. = Duvernay Formation, MN = Montagne Noire. Note: The sampled intervals that were barren of conodonts, or those that yielded only indeter- minate fragments, have been omitted. BEAVERHILL LAKE GROUP, CENTRAL ALBERTA, CANADA: UYENO nterval (ft) nterval (m) Icriodus subterminus Polygnathus alatus Anc. rotundiloba \ate Pandorinellina insita Ozark. sannemanni Ozarkodina brevis Skeletognathus norrisi Polygnathus webbi Mesotaxis distinctus Ancyrodella triangulata Mesotaxis keithi AND WENDTE lol Pol. cf. P. decorosus Mehlina gradata ke Ancyrodella rugosa Meso. asymmetrica Mesotaxis ovalis Playfordia primitiva Ancyrodella recta |Ancyrodella alata Polygnathus tedi Anc. postbinodosa Ancyrodella africana Pol. angustidiscus Meso. bogoslovskyi Pol. xylus xylus Conodont zones 8319.5-8320.5)2535.8-2536.1 | Pal. paradisparilis >| ><|Polygnathus dubius 8323.5-8325.0/2537.0-2537.5 *<| | /criodus expansus D. Fm. |Cycles/Formations 8329.5-8332.0)2538.8-2539.6| >| >| >| Palmatolepis transitans x 8335.5-8337.5}2540.7-2541.3 8341 .0-8343.0/2542.3-2542.9 8344.5-8347.0/2543,4-2544 2 8351 .0-8353.0/2545.4-2546.0 &\£/&|S|8/&|S) S\Sample No. 8356.5-8358.0)2547.1-2547.5 8359.5-8360.5}2548 .0-2548.3 8363.0-8365.0|2549.0-2549.7) 8368,5-8370.5)2550.7-2551.3 8374.5-8377.0|2552.5-2553.3 8 |8384.0-8385.5)2555.4-2555.9) 34B 8420.3-8421.0/2566.5-2566.7| 34A\8423.5-8424 0/2567.5-2567.6 8426.0-8428.5/2568.2-2569.0 8436.0-8438.0)2571.3-2571.9 8439.0-8441.0)2572.2-2572.8 8444 0-8445.0/2573.7-2574.0 8449 ,0-8451.0,2575.3-2575.9 8453.5-8456.0/2576.6-2577.4 8461.0-8463.0/2578.9-2579.5 8464.5-8466.5)/2580.0-2580.6 8468 .0-8470.5)2581.0-2581.8 ><] KK] | >K | OK | >< | OK] OK | OK OK | >< 8473.0-8475.5|2582.6-2583.3 84820-8484 5/2585.3-2586.1 8488 .0-8490.5/2587.1-2587.9) 8493.0-8495.5|2588 .7-2589.4) 8500.5-8503.0/2591 .0-2591.7| 8510.5-8513.0/2594 0-2594.8 8519.0-8521.5)2596.6-2597.4 8527.0-8529.5|2599.0-2599.8 8536.5-8539.0/2601.9-2602.7| 8546.5-8549.0|2605.0-2605.7 8559.5-8562.0|2608.9-2609.7 8564.5-8567.0/2610.5-2611.2 8571.5-8574.0)2612.6-2613.4 8576.0-8578.5/2614.0-2614.7 8583.0-8585.5|2616.1-2616.9 8590.0-8592.5)2618.2-2619.0 8595,.5-8598.0/2619.9-2620.7 8603.5-8605.5)2622.3-2623.0 cf 8613.0-8615.5)2625,.2-2626.0 cf 8621.5-8624.5/2627.8-2628.7 ct/x 8625.5-8627.5/2629.1-2629.7) 8629.0-8632.0/2630, 1-2631.0 8634.0-8636.0/2631 .6-2632.3 8639.5-8642.0/2633.3-2634.1 Text-figure 8.—Distribution of conodonts in the Beaverhill Lake Group in the Imperial Forestry 16-7-64-10W5 well. (See caption to Text-fig. 7 for abbreviation and notes.) occurrences of Ozarkodina sannemanni in both wells are within MN Zone 2. MN Zone 3 is defined with its base and top at the first appearances of Ancyrodella rugosa and Palma- tolepis transitans, respectively (Klapper, 1989). In the Beaverhill Lake sequence, P. transitans makes a late appearance, based on graphic correlation by Klapper (pers. commun., 1995). The top of the zone is instead marked by the first occurrence of A. postbinodosa, which is restricted to Zone 4, again based on graphic correlation by Klapper (pers. commun., 2000). Using this revised base of MN Zone 4 (and therefore, the top of MN Zone 3), the zone is present in the Forestry well within the interval of 2587.1 to 2620.7 m, and in the Archie well, 2203.2 to 2235.6 m. The species con- fined to this zone include A. recta, possibly A. trian- > ©) a Oo (aa) Z. faa) jaa} BEAVERHILL LAKE GROUP, CENTRAL ALBERTA, CANADA: UYENO AND WENDTE 163 gulata, and Polygnathus tedi in both wells, and in the Forestry well only, Mesotaxis distinctus and M. keithi. The species with their lowest occurrences within this zone include Polygnathus cf. P. decorosus of Uyeno (1974), A. alata, M. asymmetrica, and M. ovalis in both wells, and Playfordia primitiva in the Forestry well only. As noted above, the base of MN Zone 4 in the pres- ent study is at the first occurrence of Ancyrodella post- binodosa. Using this definition, the zone is present in the Forestry well within the interval of 2535.8 to 2586.1 m, and in the Archie well, 2165.0 to 2200.7 m. In the Forestry well, Palmatolepis transitans makes its first appearance at 2539.6 m, and in the Archie well, at 2165.5 m. That the occurrences in the Forestry well are high in MN Zone 4, and approaching MN Zone 5, is suggested by a form of P. transitans that may be transitional to P. gutta (see under P. transitans in the Systematics section). Mesotaxis bogoslovskyi and P. paradisparilis also occur high within the zone, while A. africana has a longer range within the zonal inter- val. No conodonts to suggest the presence of MN Zone 5 were found in either of these wells. SYSTEMATIC PALEONTOLOGY All of the genera listed in this section belong to the Polygnathidae, in the sense used by Klapper, Kuz’ min, and Oynatanova (1996, p. 137). The distribution of the listed conodonts is given in Text-figures 7 and 8. The primary type and figured specimens are depos- ited in the collection of the Geological Survey of Can- ada (GSC), 601 Booth Street, Ottawa, Ontario. Family POLYGNATHIDAE Bassler, 1925 Genus ANCYRODELLA Ulrich and Bassler, 1926 Type species.—Ancyrodella nodosa Ulrich and Bas- sler, 1926, p. 48. Ancyrodella postbinodosa, new species Plate 1, figures 16-19 Diagnosis.—Pa element with two distinctly large nodes on either side of platform; nodes may be accom- panied by up to three much smaller nodes on one side, or both sides, of platform. Platform outline asymme- trical, with straight outer that is parallel with keel, and a rounded inner. Upper surface may have faint anter- iorly-pointed ridges running from central node. Free blade and carina form very gentle curve. Denticles on free blade and posterior part of carina higher than those on mid-carina. Basal pit moderate-sized, with traces of laterally- or anteriorly-directed secondary keels. Remarks.—Pa element is similar to Ancyrodella binodosa Uyeno, from which it differs primarily in its asymmetrical platform outline. The latter has rounded platform margins on both sides, and also a larger basal pit at similar growth stages. Based on graphic corre- lation (Klapper, pers. commun., 2000), the new species makes its first appearance in MN Zone 4. In this study, the lowest occurrence is taken as the base of that zone. PLATE 1 All specimens of Pa elements. All figures *50. All depth intervals have been corrected to logs. “Archie well” cited below is the Pan American Home A-1 Archie 4-1-66-8W5 well, GSC locality number C-222352; ‘‘Forestry well” is the Imperial Forestry 16-7-64-10W5 well, GSC locality number C-222353. 1, 2. Ancyrodella rotundiloba (Bryant, 1921), early form of Klapper (1985) 1, 2. GSC 122721: Upper and lower views. Archie well, sample 15 (7516.0—7517.5 ft; 2290.0—2291.3 m). 3, 8, 9. Ancyrodella alata Glenister and Klapper (1966) 3. GSC 122722: Lower view. Forestry well, sample 12 (8571.5—8574.0 ft: 2612.6—2613.4 m). 8, 9. GSC 122723: Lower and upper views. Archie well, sample 45 (7298.0—7299.8 ft; 2224.4—2225.0 m). 4, 5. Ancyrodella rotundiloba (Bryant, 1921), late form of Klapper (1985) 4, 5. GSC 122724: Upper and lower views. Forestry well, sample 5 (8621.5—8624.5 ft; 2627.8—2628.7 m). 6, 7. Ancyrodella triangulata Kralick (1994) 6, 7. GSC 122725: Upper and lower views. Forestry well, sample 8 (8595.5—8598.0 ft; 2619.9—2620.7 m). 10, 11. Ancyrodella rugosa Branson and Mehl (1934) 12, 13. Ancyrodella recta Kralick (1994) 12, 13. GSC 122727: Lower and upper views. Forestry well, sample 13 (8564.5—8567.0 ft; 2610.5—2611.2 m). 14, 15. Ancyrodella africana Garcia-L6pez (1981) 14, 15. GSC 122728: Upper and lower views. Archie well, sample 66 (7169.5—7171.0 ft; 2185.3-2185.7 m). 16-19. Ancyrodella postbinodosa, n.sp. 16, 17. GSC 122729 (holotype): Upper and lower views. Archie well, sample 60 (7218.3—7220.3 ft; 2200.1—2200.7 m). 18, 19. GSC 122730 (paratype): Upper and lower views. Forestry well, sample 25 (8468.0—8470.5 ft; 2581.0—2581.8 m) BULLETIN 369 BEAVERHILL LAKE GROUP, CENTRAL ALBERTA, CANADA: UYENO AND WENDTE 165 Stratum typicum and locus typicus.—Beaverhill Mesotaxis distinctus Ovnatanova and Kuz’ min, Lake Group, Archie well, sample 60 (7218.3—7220.3 199] ft; 2200.1—2200.7 m). Plate 2, figures 1, 2 Type series.—Holotype, the specimen illustrated in Plate 1, figures 16, 17 (GSC 122729). Paratype, GSC Mesotaxis distinctus Ovnatanova and Kuz’ min (1991, p. 45, 47, pl. Ieetiesel 2): 122730. ; Derivation of name.—In reference ue the close sim- Remarks.—One of the key characteristics of this ilarity of the species to Ancyrodella binodosa Uyeno, species is the carina that terminates before the poste- 1967. rior end of the platform. There are two forms in the present material, one with a broad platform, and the Genus MESOTAXIS Klapper and Philip, 1972 other with narrow platform. The latter form may have adcarinal areas that are free of nodes, and in this re- Type species.—Polygnathus asymmetricus Bischoff spect differs from the holotype specimen. There seems and Ziegler, 1957, pp. 88-89. to be no biostratigraphic significance to the forms a PLATE 2 All specimens of Pa elements, unless otherwise indicated. All figures *50. All depth intervals have been corrected to logs. “‘Archie well” cited below is the Pan American Home A-1 Archie 4-1-66-8W5 well, GSC locality number C-222352; “‘Forestry well” is the Imperial Forestry 16-7-64-10W5 well, GSC locality number C-222353. 1, 2. Mesotaxis distinctus Ovnatanova and Kuz’ min (1991) 1. GSC 122731: Upper view. Forestry well, sample 8 (8595.5—8598.0 ft; 2619.9—2620.7 m). 2. GSC 122732: Upper view. Forestry well, sample 8 (8595.5—8598.0 ft; 2619.9—2620.7 m). 3, 4. Skeletognathus norrisi (Uyeno, 1967) 3, 4. GSC 122733: Upper and lateral views. Forestry well, sample 7 (8603.5—8605.5 ft; 2622.3—2623.0 m). 5-7. Mesotaxis keithi, n.sp. 5. GSC 122734 (paratype): Lower view. Forestry well, sample 8 (8595.5—8598.0 ft; 2619.9—2620.7 m). 6. GSC 122735 (paratype): Lower view. Forestry well, sample 8 (8595.5—8598.0 ft; 2619.9—2620.7 m). 7. GSC 122736 (holotype): Upper view. Forestry well, sample 8 (8595.5—8598.0 ft; 2619.9—2620.7 m). 8. Mesotaxis bogoslovskyi Ovnatanova and Kuz’ min (1991) 8. GSC 122737: Upper view. Archie well, sample 72 (7122.0—7125.5 ft; 2170.8—2171.9 m). 9-11. Palmatolepis paradisparilis, n.sp. 9. GSC 122738 (paratype): Upper view. Archie well, sample 75 (7103.0—7104.5 ft; 2165.0—2165.5 m). 10. GSC 122739 (holotype): Lower view. Forestry well, sample 48 (8329.5—8332.0 ft; 2538.8—2539.6 m). 11. GSC 122740 (paratype). Upper view. Archie well, sample 75 (7103.0—7104.5 ft; 2165.0—2165.5 m). 12, 13, 16-18. Polygnathus tedi, n.sp. 12, 13. GSC 122741 (paratype): Lower and upper views. Archie well, sample 45 (7298.0—7299.8 ft; 2224.4—2225.0 m). 16, 17. GSC 122742 (holotype): Upper and lateral views. Forestry well, sample 13 (8564.5—8567.0 ft; 2610.5—2611.2 m). 18. GSC 122743 (paratype): Lateral view of Pb element. Forestry well, sample 13 (8564.5—8567.0 ft; 2610.5—2611.2 m). 14. Mehlina gradata Youngquist (1945) 14. GSC 122744: Lateral view. Forestry well, sample 12 (8571.5—8574.0 ft; 2612.6-2613.4 m). 15. Playfordia primitiva (Bischotf and Ziegler, 1957) 19. Ozarkodina sannemanni (Bischoff and Ziegler, 1957) 19. GSC 122746: Upper view. Forestry well, sample 5 (8621.5—8624.5 ft; 2627.8—2628.7 m). 20, 21. Icriodus subterminus Youngquist (1947) 20, 21. GSC 122747: Upper and lateral views of I element. Forestry well, sample 5 (8621.5—8624.5 ft; 2627.8—2628.7 m). 22, 23. Polygnathus ct. P. decorosus Stauffer (1938) of Uyeno (1974) 22. GSC 122748: Upper view. Archie well, sample 58 (7232.3—7233.3 ft; 2204.4—2204.7 m). 23. GSC 122749: Upper view. Forestry well, sample 23 (8482.0—8484.5 ft; 2585.3—2586.1 m). 24, 25. Palmatolepis transitans Miller (1956) 24, 25. GSC 122750: Upper and lower views. Forestry well, sample 48 (8329.5—8332.0 ft; 2538.8-2539.6 m). 26. Polygnathus incompletus Uyeno (1967) 26. GSC 122751: Upper view. Archie well, sample 15 (7516.0—7517.5 ft; 2290.0—2291.3 m). 27. Polygnathus alatus Huddle (1934) 27. GSC 122752: Upper view. Forestry well, sample 8 (8595.5—8598.0 ft; 2619.9—-2620.7 m). 166 BULLETIN 369 since they occur in similar intervals. Similar variations were noted by Klapper (1989) in Polygnathus dengleri Bischoff and Ziegler. Mesotaxis keithi, new species Plate 2, figures 5—7 Diagnosis.—Pa element with symmetrical to slight- ly asymmetrical platform. Platform upper surface cov- ered with fine nodes, with free blade and carina form- ing straight line. Carina extends to posterior end of platform. Free blade about half of platform length. Pit small, surrounded by large, symmetrical basal cavity, located mid-way between mid-length and anterior end of platform. Remarks.—In its symmetrical platform outline, the new species resembles Mesotaxis ovalis (Ziegler and Klapper), although it tends to be more slender. It dif- fers from the latter primarily in the shape and position of the basal cavity; in M. ovalis, the basal cavity is more asymmetrical and located in mid-length of plat- form. Stratum typicum and locus typicus.—Beaverhill Lake Group, Forestry well, sample 8 (8595.5—8598.0 ft; 2619.9—-2620.7 m). Type series.—Holotype, the specimen illustrated in Plate 2, figure 7 (GSC 122736). Paratypes, GSC 122734 and 122735. Derivation of name. From proper noun, Keith. Genus PALMATOLEPIS Ulrich and Bassler, 1926 Type species.—Palmatolepis perlobata Ulrich and Bassler, 1926, p. 49. Palmatolepis paradisparilis, new species Plate 2, figures 9-11 Palmatolepis disparilis Ziegler and Klapper?. Uyeno, 1991, p. 144, pl. 3, figs. 20, 21. Diagnosis.—Pa element with asymmetrical plat- form, the outer lobe slightly to moderately developed: lobe oriented laterally to slightly anteriorly. Upper sur- face smooth to sparsely nodose. Free blade-carina out- line straight to slightly curved, with carina terminating before posterior end of platform. Basal pit large, asym- metrical, L-shaped, and clearly raised above surround- ing platform. Remarks.—The basal pit of the present species is similar in shape and size to that of Palmatolepis dis- parilis Ziegler and Klapper. The principal difference is in the outline of the platform, which in P. parad- isparilis is more slender, with a narrow inner side, and a lobe on the outer. Platform of P. disparilis is also more robust and its upper surface more nodose. Stratum typicum and locus typicus.—Beaverhill Lake Group, Forestry well, sample 48 (8329.5—8332.0 ft; 2538.8—2539.6 m). Type series.—Holotype, the specimen illustrated in Plate 2, figure 10 (GSC 122739). Paratypes, GSC 122738 and 122740. Derivation of name.—In reference to the close sim- ilarity of the species to Palmatolepis disparilis Ziegler and Klapper. Palmatolepis transitans Miiller (1956) Plate 2, figs. 24, 25 Palmatolepis transitans Miiller, 1956, pp. 18-19, pl. 1, fig. 1; Klap- per, Kuz’min, and Oynatanova, 1996, pp. 149-150, fig. 9.14 [see for further synonymy]; Kuz’min, 1998, pl. 7, fig. 1, pl. 8, figs. 1, 6, 7; Ding, Jiang, and Bai, 2000, pl. 1, fig. 18. Remarks.—The specimen in PI. 2, figs. 24, 25 here- in differs slightly from the holotype in having a small sinus at the outer margin immediately adjacent to the posterior end of the platform. Its slightly rounded outer posterior margin is similar to the specimen illustrated by Kuz’min (1998, pl. 8, fig. 6), a form which he considered to be transitional to Palmatolepis gutta Kuz’ min. P. gutta, a name given to a species that was left in open nomenclature by Uyeno (1991, pl. 3, figs. 24, 25; pl. 4, figs. 1, 2), is associated with Polygnathus timanicus Ovnatanova in the eastern Canadian Cordil- lera. P. timanicus has its lowest occurrences within MN Zone 5 (Klapper, 1997). Genus POLYGNATHUS Hinde, 1879 Type species.—Polygnathus dubius Hinde, 1879, pp. 361-302. Polygnathus tedi, new species Plate 2, figures 12, 13, 16-18 Ozarkodina(?) aff. proxima (Pollock, 1968). Racki and Bultynck, 1993, pl.3; fig. 12. Diagnosis.—Pa element with an extended platform on either side, reaching to or almost to, the anterior and posterior ends. Free blade may therefore be ex- tremely short. Platform widest adjacent to the basal cavity and main cusp. Upper surface of platform smooth; the widest part may have a node on one or both sides. The free/fixed blade-carina outline almost straight to gently incurved or sinuous. Unit gently arched as laterally viewed. Anterior of the cusp, the carina-free/fixed blade outline rises gently or steeply, with highest point near anterior end, followed by 2 or 3 small denticles. Basal pit moderately large, located about one-third of unit length from posterior end, with keels extending to both ends. Remarks.—Some specimens with sinuous free/fixed blade-carina outline superficially resemble Tortodus sp. A of Sparling (1999). The latter differs in several BEAVERHILL LAKE GROUP, CENTRAL ALBERTA, CANADA: UYENO AND WENDTE 167 aspects, however, including absence of any free blade, more central position of basal cavity and lack of large nodes on platform. Polygnathus beckmanni Bischoff and Ziegler similarly has fixed blade, but displays strong ridges on the platform. The Pa element of the genus Polygnathellus Ulrich and Bassler (1926), as exemplified by its type species, P. typicalis, differs from Polygnathus tedi in its den- ticulation pattern: as laterally viewed, the outline of the denticles slopes downward from the main cusp, located over the pit, towards both ends. The Pa element with fixed blade superficially resem- bles Ancyrognathus ancyrognathoideus (Ziegler). The latter differs from the present species in displaying a platform that 1s more uniformly tapering, with no abrupt widening adjacent to the cusp; also, there are no nodes on the platform. A large Pb element was recovered with the Pa ele- ment of Polygnathus tedi. It is similar to some Pb el- ements assigned to Ancyrognathus, and illustrated by Klapper (1990, figs. 7.13 and 8.14). It has morpholog- ical similarities to the Pa elements in its general ro- bustness, and large cusp, the wide ledge, and moder- ately large pit. Stratum typicum and locus typicus.—Beaverhill Lake Group, Forestry well, sample 13 (8564.5—8567.0 ft; 2610.5—2611.2 m). Type series.—Holotype, the specimen illustrated in Plate 2, figures 16, 17 (GSC 122742). Paratypes, GSC 122741 and 122743. Distribution.—Found in MN Zone 3. Also in MN Zone 3 equivalent in the Kielce area, Holy Cross Mountains of southern Poland (Racki and Bultynck, 1993). Derivation of name. rivative of Theodore. From proper noun, Ted, a de- Polygnathus cf. P. decorosus Stauffer of Uyeno, 1974 Plate 2, figures 22, 23 Polygnathus cf. P. decorosus Stauffer. Uyeno, 1974, p. 38-39, pl. 4, figs. 2, 7; pl. 5, fig. 2. Diagnosis.—The free blade of the Pa element about half of unit length, and is extremely high at its mid- point, and abruptly or gradually sloping downward at anterior end. Unit straight to gently incurved. Lateral outline shows lower margin of unit gently and contin- uously arched. Pit narrow, of moderate size, surround- ed by inverted basal cavity. Platform saggitate, rimmed with subdued nodes, or abbreviated, not reaching the posterior end. Remarks.—The specimen illustrated by Uyeno (1974, pl. 4, fig. 7C) displays a wide inverted basal cavity; its full platform development is similar to the specimen in Plate 2, figure 23. The specimen in Plate 2, figure 22, with abbreviated platform, is similar to that in Uyeno (1974, pl. 4, fig. 2). REFERENCES CITED Bai, S.L., Bai, Z.Q., Ma, X.P., Wang, D.R., and Sun, Y.L. 1994. Devonian events and biostratigraphy of South China. Pe- king University Press, 303 pp. Balinski, A. 1979. Brachiopods and conodonts from the Frasnian of the Deb- nik Anticline, southern Poland. Palaeontologia Polonica, no: 39) pp: 3=95. Bassler, R.S. 1925. Classification and stratigraphic use of conodonts. Geolog- ical Society of America Bulletin, vol. 36, pp. 218-220. Bischoff, G., and Ziegler, W. 1957. Die Conodontenchronologie des Mitteldevons und des tiefsten Oberdevons. 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Sihongshan section, a regional reference section for the Lower-Middle and Middle-Upper Devonian boundaries in east Asia. Courier Forschungsinstitut Senckenberg, vol. 75, pp. 17-38. APPENDIX For those species that are illustrated but not dis- cussed in the Systematic Paleontology section, a brief synonymy is provided. Unlike conventional synonymy style, no attempt is made to trace the history of no- menclatural changes; rather, to conserve space, the names used in the references are omitted. The name preferred herein, however, is at the head of each entry. Ancyrodella africana Garcia-L6opez (1981) Plate 1, figures 14, 15 Garcia-Lopez, 1981, pp. 264-265, pl. 1, figs. 1-14; Klapper, 1985, pp. 28-29, pl. 8, figs. 11-22; pl. 9, figs. 1-16; text-figs. 3S, T, AA, BB; Garcia-Lopez, 1987, pp. 57-58, pl. 2, figs. 8-19; Van- delaer et al., 1990, p. 329, pl. 1, figs. 6, 7. Ancyrodella alata Glenister and Klapper (1966) Plate i; fisuress3; 85.9) Glenister and Klapper, 1966, pp. 799-800, pl. 85, figs. 1-8; Weary and Harris, 1994, pl. 2, figs. 11-14; Kralick, 1994, p. 1393, pl. 3, figs. 1, 2 [?]; pl. 4, figs. 5, 6 [?]; Bai er al., 1994, pl. 2, figs. 1, 3; Ding er al., 2000, pl. 1, figs. 9, 10, 13, 14. Ancyrodella recta Kralick (1994) Plate 1, figures 12, 13 Kralick, 1994, pp. 1387, 1390, figs. 3.5, 3.6, 3.11, 3.12, 4.11, 4.12, 6.1, 6.2, 6.5, 6.6, 6.9, 6.10; Racki and Bultynck, 1993, pl. 9, figs. SG: Ancyrodella rotundiloba (Bryant, 1921) Plate 1, figures 1, 2, 4,5 Bryant, 1921, pp. 26-27, pl. 12, figs. 1-6; Klapper, 1985, pp. 24, 26-27, pl. 1, figs. 1-20; pl. 2, figs. 1-12: pl. 3, figs. 1-12: pl. 4, figs. 9-12; pl. 8, figs. 9, 10; pl. 11, figs. 3, 4; text-fig. 3 A-J, M, N [synonymy]; Racki and Bultynck, 1993, pl. 6, fig. 8; Kralick, 1994, p. 1387, figs. 3.15—3.24, 4.7, 4.8, 5.3, 5.4, 5.7-5.11 [syn- onymy]; Weary and Harris, 1994, pl. 2, figs. 1-10, 19-21; Bai et al., 1994, pl. 1, figs. 2, 3, 8. Ancyrodella rugosa Branson and Mehl (1934) Plate 1, figures 10, 11 Branson and Mehl, 1934, p. 239, pl. 19, figs. 15, 17; Racki and Bultynck, 1993, pl. 8, figs. 10, 11; Weary and Harris, 1994, p. 217, pl. 1, figs. 14, 15; Iudina, 1995, pl. 1, fig. 10. Ancyrodella triangulata Kralick (1994) Plate 1, figures 6, 7 Kralick, 1994, pp. 1390, 1393, figs. 3.3, 3.4, 3.9, 3.10, 4.1—-4.4, 6.3, 6.4, 6.7, 6.8, 6.11, 6.12. Icriodus subterminus Youngquist (1947) Plate 2, figures 20, 21 Youngquist, 1947, p. 103, pl. 25, fig. 14; Racki and Bultynck, 1993, pl. 3, fig. 8: Rogers, 1998, p. 737, figs. 6.2-6.6 [synonymy]. Mehlina gradata Youngquist (1945) Plate 2, figure 14 Youngquist, 1945, p. 363, pl. 56, fig 3; Klapper and Lane, 1985, p. 921, fig. 12.1 [synonymy]; Uyeno, 1991, pl. 5, fig. 27. Mesotaxis bogoslovskyi Ovnatanova and Kuz’ min (1991) Plate 2, figure 8 Ovnatanova and Kuz’ min, 1991, p. 45, pl. 1, figs. 8-10; Klapper er al., 1996, p. 140, pl. 6, figs. 11, 12; Kuz’min er al., 1997, fig. Le: Ozarkodina sannemanni (Bischoff and Ziegler, 1957) Plate 2, figure 19 Bischoff and Ziegler, 1957, pp. 117-118, pl. 19, figs. 15, 19-23, 25; Pollock, 1968, p. 439, pl. 63, figs. 22, 24, 25; Bultynck and Hollard, 1980, pl. 10, figs. 1-3; Perri and Spalletta, 1981, p. 308, pl. 7, fig. 11; Bultynck, 1983, figs. 1.10, 1.11. Playfordia primitiva (Bischoff and Ziegler, 1957) Plate 2, figure 15 Bischoff and Ziegler, 1957, p. 83, pl. 21, figs. 5-9; Glenister and Klapper, 1966, p. 827, pl. 95, figs. 19, 20; Uyeno, 1974, p. 36, pl. 6, figs. 6, 7; Ziegler and Wang, 1985, pl. 3, fig. 14; Uyeno, 1991, pl. 5, fig. 12. Polygnathus alatus Huddle (1934) Plate 2, figure 27 Huddle, 1934, p. 100, pl. 8, figs. 19, 20; Klapper and Lane, 1985, p. 932, figs. 16.15—16.17 [synonymy]; Metzger, 1989, p. 518, figs. 15.1, 15.2; Uyeno, 1991, pl. 5, fig. 7; Racki and Bultynck, BEAVERHILL LAKE GROUP, CENTRAL ALBERTA, CANADA: UYENO AND WENDTE 171 1993, pl. 4, figs. 7, 8; Weary and Harris, 1994, pl. 1, fig. 12; Skeletognathus norrisi (Uyeno, 1967) i al., 2 a3 ‘ Ziegler et al., 2000, pl. 6, fig. 3. Plate 2, figures 3, 4 Polygnathus incompletus Uyeno (1967) : Plate 2 fieure 26 Uyeno, 1967, p. 10, pl. 2, figs. 4, 5: Perri and Spalletta, 1981, pp. —ene Es 305-306, pl. 7, figs. 5, 6; Uyeno in Norris et al., 1982, p. 75, pl. 36, figs. 23-30, 34-39; Sandberg er al., 1989, p. 214, pl. 5, figs. 1—12 [synonymy]); Racki and Bultynck, 1993, pl. 3, figs. 9, 10; Kirchgasser, 1994, pl. 3, figs. C, K, M-O. Uyeno, 1967, pp. 7, 10, pl. 2, figs. 6, 7; Klapper in Ziegler, ed., 1975, pp. 291-292, Polygnathus-pl. 5, fig. 4: Balinski, 1979, p. 80, pl. 23, fig. 11. TIMING OF CONODONT EVOLUTION: SCHULKE et al. ifs} TIME ELAPSED IN THE COURSE OF CONODONT EVOLUTION AFTER THE KELLWASSER MASS EXTINCTION (EARLY FAMENNIAN, LATE DEVONIAN) IMMO SCHULKE, NICOLA LEVY, AND MATTHIAS SPIEHL Institut fiir Geologie und Paleontologie der Universitat Hannover Callinstrasse 30, D—30167 Hannover email: schuelke @ geowi.uni-hannover.de ABSTRACT The conodont stratigraphy of the early Famennian sequence of the Montagne Noire is compared with a time series analysis of sedimentological proxy data. The results of the time series analysis indicate that deposition of calcareous sediments was mainly triggered by surface water carbonate productivity. Thus, a cyclical pattern of carbonate sedimentation has been reconstructed that probably reflects the 0.1 Ma Milankovitch cycle. If correlated with the respective conodont zones, a highly unequal conodont zonal duration results for the time interval analyzed. Especially, the basal Famennian triangularis Zone has a very short duration which indicates a conodont faunal recovery after the Kellwasser mass extinction much shorter than estimated. INTRODUCTION The Late Devonian biotic crisis, which had its cli- max with the Kellwasser mass extinction at the Fras- nian-Famennian boundary, is regarded as one of the five major mass extinctions in Phanerozoic life history (McLaren, 1970). It was named ‘‘Kellwasser event” by Walliser (1980, 1984). Numerous authors have since focused their investigations on the extinction and recovery of various faunal elements involved in this major faunal turnover and on the mechanisms and pro- cesses that lead to a mass extinction of the magnitude of the Kellwasser event. Significant articles that con- sidered these topics include Schindler (1990) and Bug- gisch (1991). We do not wish to renew the discussion of all aspects of a global process as complex as the Kellwasser event, but to focus on an important single aspect, namely the timing and duration of faunal re- covery of conodonts after the extinction. Conodonts provide the best fossil record to justify such an analysis because they range continuously through the event horizon and are by far the most abundant fossil group below and above the mass ex- tinction layer. In addition, their behaviour and faunal development across the Kellwasser event is extraor- dinarily well documented throughout the world (e.g., Ziegler and Lane, 1987; Sandberg er al., 1988; Ziegler and Sandberg, 1990; Schindler, 1990; Klapper er al., 1993: Schiilke, 1995, 1996, 1998, 1999a,b; Morrow and Sandberg, 1996; Morrow, 2000; Schindler er al., 1998 and many others). Nevertheless, in only a few articles are estimates on the duration and timing of the faunal recovery given (e.g., Sandberg and Ziegler, 1992; Morrow and Sandberg, 1996; Schiilke 1998, 1999a,b). These estimates are based chiefly on assumptions of average conodont zonal duration in the Late Devonian (e.g., Sandberg et al., 1988; Ziegler and Sandberg, 1990, 1998; Morrow and Sandberg, 1996; Sandberg and Ziegler, 1996; Schiilke, 1998). The equal time in- tervals of Famennian conodont biozones (0.5 Ma) have been calculated by Sandberg and Ziegler (1996) by the division of the (possible) duration of the Fa- mennian (10 Ma) by the number of conodont zones (20). These assumptions provide only a crude tool for time calibration—possibly the best exclusively based on biostratigraphy, but may not be used without further testing (Weddige, 1997). Such testing can be achieved by comparing conodont zones with small-scale chro- nological and periodical signals that are produced by cyclical or sequence stratigraphical approaches. In this study, we analyzed two early Famennian sections in the Montagne Noire: (1) Upper Coumiac quarry, the GSSP for the Frasnian-Famennian boundary, and (2) La Serre Trench C. Apart from the high conodont con- tent, which allowed a high resolutional conodont bio- stratigraphy (Schilke 1995, 1997a, 1999a,b), these sections expose an alternating marl- and limestone se- quence in the basal Famennian that is highly appro- priate for cyclostratigraphical approaches based on its carbonate content. Some preliminary results of the se- quence stratigraphical analysis presented here have been included in earlier publications on early Famen- nian high resolution conodont biostratigraphy (Schiilke 1999a,b) and its implications have been discussed there. Because we now have complete data sets for both sections and the results of a time series analysis, the timing of conodont recovery and the duration of Late Devonian standard conodont zones need to be re- evaluated. A time series analysis of sedimentological data as has been realized here, involves the assumption 174 BULLETIN 369 that the sedimentation rate is relatively constant and that the sequence is continuous. These assumptions may be justified retrospectively by the positive results (Swan and Sandilands, 1995) which made time series analysis a standard technique in processing sedimen- tological proxy data. In our case, the results seem to justify the application of this method, but they will nevertheless be treated and their implications dis- cussed with caution. ACKNOWLEDGMENTS Heartfelt thanks are extended to Gilbert Klapper to whom this paper is dedicated. He is one of the cono- dont workers whose lifetime work provokes the senior author to always think over the implications of mere facts and to develop new ideas concerning conodonts and their stratigraphical use. Thank you, Gil! We are indebted to the reviewers Jeff Over (Gene- seo) and Catherine Girard (Lyon) for their constructive reviews. Also, we would like to thank Jim Barrick (Lubbock) for his kind improvement of the manu- script. This study was supported by the German Re- search Foundation (DFG; proj.-no.: Schu 1214/1-1,2). GEOLOGICAL SETTING The Variscan structures of the southern Massif Cen- tral comprise the Cevennes, the Albigeois, and, most southward, the Montagne Noire. Fossiliferous Paleo- zoic sedimentary sequences of the southern Massif Central range from the Lower Cambrian well into the Carboniferous. Upper Devonian strata are best exposed in the southwestern and southeastern parts of the Montagne Noire area and belong to two tectonically separated units (e.g., Feist, 1983, 1990), the “*nappe unit” from the Mont Peyroux area and the “klippen unit” from the ““Cabrieres klippen.”’ Both tectonic units represent slightly different facies conditions and are claimed to have been transported southward (Engel et a/., 1982), but paleogeographic reconstruction of Variscan depo- sitional basins is far from settled and is beyond the scope of this paper (e.g., Scotese, 1986; Young, 1987; Morzadec ef al., 1988; Schindler, 1990; Feist and Schindler, 1994). The early Famennian sedimentary sequences of the Montagne Noire comprise alternating marlstones and limestones, mostly mud- to wackestones, with a main- ly pelagic fossil content. They were deposited in an outer shelf environment that generally lacked large- scale siliciclastic influx or bottom currents, presumably on a widespread drowned carbonate platform. The bathymetric position of this carbonate platform is yet unsettled, but is assumed to have been below storm- wave base and above the base of the photic zone (Feist and Schindler, 1994). Our analysis of microfacies pat- terns and conodont faunas indicates a water depth be- tween 100 and 200 m. LocaLity 1: ABANDONED COUMIAC QUARRY (BOUNDARY STRATOTYPE OF THE FRASNIAN/FAMENNIAN STAGE BOUNDARY) Geographic Position The abandoned Coumiac quarry is situated in the southeastern Montagne Noire, Département Hérault, about 1.5 km NE of Cessenon village and 0.175 km WSW of the Les Granges farmhouse near the road D 136 between Cessenon and Causses et Veyran (topo- graphic mapsheet 1:25 000 Murviel les Béziers) (Text- fics 1), The Frasnian part of the boundary stratotype section is exposed in the upper quarry (the northernmost of a series of three abandoned marble quarries) followed by the Frasnian/Famennian boundary above its eastern wall. The Famennian part of the section extends on the slope in a NE direction where it is exposed in natural outcrops and artificial trenches. Tectonics and Lithology Probably known to, but not reported by, former workers (e.g., Klapper et al., 1993), the most recent measuring of the Coumiac section during a field cam- paign late in 1997 revealed a small wrench fault that crosses the Famennian part of the section in a north- ward direction. The displacement amounts to about 0.80 m (Schiilke, 1999b). The early Famennian part of the section that is as- signed to the Coumiac Formation consists mainly of reddish, marly, nodular cephalopod limestones with in- tercalated marls. The basal Famennian part of the sec- tion exposes evenly bedded, reddish strata. Subse- quently, bed character changes to yellowish-red strata with knobby bedding planes. In the lowermost middle Famennian, the Coumiac Formation is overlain by the transgressive, red and partly yellow nodular limestones of the Griotte Formation. References The Coumiac section has been known as a locality for Frasnian goniatites since De Rouville (1887). The importance of this section for trilobite, goniatite and other faunal groups has been emphasized by House er al., 1985; Becker et al., 1989; Klapper, 1989; Schin- dler, 1990; Feist, 1990, 1991; Lethiers and Feist, 1991; Becker, 1993; Klapper ef al., 1993; Feist and Schin- dler, 1994; Girard, 1994a, 1994b, 1995; Girard and Feist, 1997; and Schiilke, 1995, 1996, 1997b, 1999a,b. Chemostratigraphic investigations on this section have TIMING OF CONODONT EVOLUTION: SCHULKE ef al. 175 Mazamet Carcassonne a rae Roquebrun D19 Cessenon- s-Orb Causses- et-Veyran > LaSerre_~- Text-figure 1.—Locality map of the studied sections. A: Abandoned Coumiac quarry. B: La Serre Trench C. been carried out by Joachimski and Buggisch, 1993, Grandjean ef a/., 1993, and Girard and Albarede, 1996. LOCALITY 2: LA SERRE TRENCH C Geographic Position Trench C at La Serre hill is situated in the south- eastern Montagne Noire, Département Herault (Text- fig. 1), about 2.5 km S of Cabrieres village and 450 m E of the farmhouse “‘La Rouquette” on the southern slope of the hill (topographic mapsheet 1:25 O00 Pe- zenas). Middle Devonian to Carboniferous rocks on the southern slope of La Serre hill are barely covered by soil and are frequently exposed in small natural out- crops. The section of La Serre trench C was dug under the direction of R. Feist (Montpellier) in the late 1970s and early 1980s. It extends from the upper Frasnian to strata as young as Mississippian, with well-developed Frasnian/Famennian and Devonian/Carboniferous boundary intervals. Lithology The deposits of the La Serre trench C section consist of well-bedded grey limestone, dark grey shales, marls, nodular limestones, and partly black laminated limestone beds that belong to the La Serre Formation. The lithology differs strikingly from the sequence of the Coumiac quarry both in its higher amount of in- tercalated shales and marls and the typically light to medium grey colors of calcilutite beds. The black Kell- wasser facies (black laminated limestones) is contin- uous across the Frasnian/Famennian boundary and ex- tends into middle Famennian strata. In addition, large parts of these rocks have been recrystallized to mi- crospar. When compared to Coumiac, significantly more benthic faunal elements can be recognized at La Serre (e.g., Feist and Schindler, 1994). Facies The depositional environment of the deposits ex- posed at La Serre trench C is presumed to have been 176 BULLETIN 369 shallower than that of Coumiac (e.g., Schindler, 1990; Feist and Schindler, 1994) because of its higher con- tent of benthic faunal elements. This assumption 1s sustained by the generally higher content of /criodus, a shallow water conodont taxon, although differences are not significant (Schiilke, 1999a). Schindler (1990) proposed a middle to deep carbonate ramp environ- ment, possibly situated in a slight depression. References The La Serre section has been analyzed several times for its goniatite content, beginning late in the nineteenth century (v. Koenen, 1883a,b; Frech, 1887: Bergeron, 1889; Schindewolf, 1921; Béhm, 1935; v. Gaertner, 1937). Detailed investigations of the gonia- tite succession from this locality were published in House er al. (1985) and Becker (1993). As is the case with the abandoned Coumiac quarry (loc. 1), detailed studies of conodont faunas from La Serre began in the 1980s (Klapper, 1989; Feist, 1990; Klapper and Foster, 1993; Girard, 1994b, 1995; Schiilke, 1996, 1997a, 1999a,b). Mega- and microfaunal content has been de- scribed by Flajs and Feist (1988), Schindler (1990), Feist and Schindler (1994), Derycke er al. (1995), and Levy (1999). METHODS The biostratigraphical correlation of the Coumiac and La Serre sections, based on the high-resolution conodont zonation, is presented in Schiilke (1999a,b). The investigations led to a separate regional conodont zonation for the Montagne Noire early Famennian sec- tions, which differs slightly from the Late Devonian “standard” conodont zonation (Ziegler and Sandberg, 1990). For differences and correlation of these zona- tions see Schiilke (1999a,b). The new results we discuss in the following para- graphs are based mainly on the processing of the sed- imentological proxy data by Spiehl (1999) and Levy (1999). Apart from an extensive microfacies analysis of the early Famennian sections, which was aimed to support or reject the assumption of a continuous sed- imentological record with no major distortion in the time dimension, we focused on a time series analysis of fine-scale carbonate content data of the deposits. We found no clear evidence for corruption of the sedi- mentological record (e.g., reworking, bottom currents, high siliciclasic influx, calciturbidites and so on) and consequently assumed a depositional regime that was triggered mainly by carbonate productivity and “‘pe- lagic snowing.” Otherwise, unequal “thicknesses” of the resulting cycles (Text-fig. 2) show minor changes of the sedimentation rate through time or differential effects of diagenesis on the respective deposits (e.g., [m] — Fourier frequency La Serre 760 —— Carbonate m A a ; Coumiac 6.00 5.00 5.00 N 3 e oS 4.00 5 4.00 3 s 3.00 3.00 N $ Py 2.00 a 2.00 3 Ww N 1.00 2 1.00 ae] a SS as 0.00 0.00 0 20 40 60 80 100 0 20 40 60 80 100 carbonate content [%] Text-figure 2.—Correlation of conodont biozones with carbonate content values (crossed hatched lines) and the resulting 0.1 Ma fre- quency (bold lines) of the measured sections. pressure solution), but without suppression of the ev- ident cyclical character of the sequence. The bulk samples that were analyzed for their car- bonate content were taken bed by bed. If the thickness of a single bed exceeded 8 cm, the samples were taken every five centimeters of rock thickness. Samples were broken down using standard techniques (jaw breaker, mortar and pestle). The rock flour was processed using the “Carbonate bomb,” following Miiller and Gastner (1971) for calcimetry. All carbonate content samples (160: Coumiac quarry; 96: La Serre Trench C) were measured three times, and the determined values of each sample were averaged. The deviation of the car- bonate content values was below 5% in all samples. The HCl-insoluble residue varied between 99% and 10%. Since bed-by-bed conodont data exist only for the early Famennian part of both sections, Early ri- angularis Zone to Late crepida Zone, the time series analysis of carbonate content data was run only for this interval (Text-fig. 2). For time series analysis we chose to use the Fast Fourier Transform (FFT), which offers a rapid exe- cution at the expense of the following constraints: 1. The data must be regularly spaced through time and the number of observations must be 2” where 7 1s an integer. There should be no trend in the data. in) TIMING OF CONODONT EVOLUTION: SCHULKE et al. GPF Amplitude [% carbonate] al sill 3 ad 8T 4T 8T Aili Frequency [T= minimum wavelength] B= Amplitude [% carbonate] at =a Ble a a 2T Frequency [T= minimum wavelength] Text-figure 3.—Power spectra showing the results of the “Fast Fourier Transform (FFT) executed on carbonate proxy data from the early Famennian sections at Coumiac (A) and La Serre (B). Arrows indicating “dominant” waveform used for inverse Fourier transformation. 3. Only integer frequencies are calculated. Fourier methods are aimed to decompose a time se- ries into a suite of waveforms, the sum of which are regarded to form the sequence of data. The resulting power spectra (Text-fig. 3) show the amplitude of each of the integer frequencies. The cyclicity in a time se- ries will normally be represented by a significant spike in the power spectra. As can be seen from Text-figure 3, both power spectra show that the possible cyclicity in the sections results from a variety of waveforms of similar and comparatively low amplitude, one of which has a slightly elevated spike. This means that even the most influential cyclical process in the sedi- mentation of the early Famennian deposits produces only a weak signal. For both sections the highest spike, indicating the most powerful single waveform, has been used to carry out an inverse Fourier transform in order to single out the most dominant cyclicity (Text- fig. 2) and remove noise from time series data. POSSIBLE FREQUENCIES AND MISTAKES The major processes forming marl-limestone alter- nations and black shale-carbonate alternations were summarized by Einsele and Ricken (1991) as follows: 1) Productivity cycles that are formed entirely by changes in organic surface water carbonate produc- tivity. 2) Dilution cycles that are triggered by oscillating ter- rigenous input. 3) Dissolution cycles that are produced by rhythmic oscillation of lysocline and CCD. 4) Calcareous redox cycles indicate fluctuating oxy- genation of bottom waters, which coincides with primary organic carbon productivity in surface wa- ter. 5) Diagenetic overprinting enhances original carbon- ate-clay differences between beds by carbonate re- distribution. The true mechanism, or the combination of mech- anisms, that formed the early Famennian sequence in the Montagne Noire can only be determined by ex- cluding or discounting the influence of others. A com- plete modification of originally homogeneous sedi- ments exclusively by diagenetic redistribution of car- bonate is unlikely, although diagenesis definitely played a role. Existing pressure solution phenomena (stylolites, clay seams) are significant, but far too ob- scure to lead to carbonate content values below 1% in black shale interbeds. Also, the influence of pre-dia- genetic dissolution of the sediments by oscillations of the CCD or the lysocline can be excluded in environ- ments with a water depth above 200 m—even in the middle Palaeozoic with its possibly different oceano- graphic conditions. Finally, we think that a fluctuating input of the detrital phase may have occurred, but car- bonate content values below detection limits cannot be produced exclusively by this process. Either primary productivity of organic carbonate in surface water or bottom water oxygenation due to surface water organic carbon production presumably controlled the rate of pelagic carbonate mud production in this geological setting. Most simply, changes in the surface water produc- tivity are triggered by climatic changes and water tem- perature (Ricken, 1986; Hering, 1995). These changes can be caused by orbital forcing and global or region- al-scale tectonics (Smith, 1994). During the time in- terval investigated, two large-scale T/R-events are re- corded that are positioned in the Middle/Late trian- gularis Zone and the Middle crepida Zone (Johnson et al., 1985; Schiilke, 1999a,b). Both events are easily detectable in the early Famennian conodont record by 178 BULLETIN 369 a change in faunal composition (Schiilke, 1999a,b), but do not necessarily represent cyclical processes. They are presumed to have been caused by global-scale tec- tonics and have been interpreted as third-order cycles with ‘“‘average”’ durations of about 1.5 Ma (e.g., John- son ef al., 1985). Our cyclical signals show much high- er frequencies and are, therefore, assumed to be pro- duced by changes of orbital parameters (Milankovitch cycles). In order to extract the maximum frequency resolv- able (the Nyquist frequency) with the minimum wave- length, which is double the interval between the ob- servations, we needed at least a crude estimation of the possible duration of the interval under consider- ation. The formerly best estimates are based on the calculations of average conodont zonal length in the Famennian of Sandberg and Ziegler (1996). These au- thors (and others) presume an average and almost con- stant conodont zonal duration of about 0.5 Ma during the whole Famennian, save a few zones with shorter durations in the middle Famennian. Consequently, our time interval would have lasted about 2.5 to 3 Ma following these assumptions. Therefore, the Nyquist frequency is calculated to have a minimum wavelength of about 30 ka, which corresponds with Milankovitch cyclicity. Other estimates of the possible duration of the time interval considered can be based on rock thickness, for example. The Montagne Noire Famen- nian succession in the Mont Peyroux area where the abandoned Coumiac quarry is situated (loc. 1) is about 70 m thick (Feist, 1990). The measured section has a thickness of 8 m (Schiilke, 1999b; Spiehl, 1999) which is about 12% of the total thickness of the Famennian. Given a total duration of the Famennian of 10 Ma (Sandberg and Ziegler, 1996), the interval considered would have lasted about 1.2 Ma. Presumably, the above two estimates (3 and 1.2 Ma) are the limits be- tween which the timespan may have varied. Which of the orbital parameters had the highest in- fluence on carbonate productivity on the Montagne Noire carbonate platform during the early Famennian can only be assumed. Usually, in areas at low latitudes between 20° and 30°, which is the paleogeographic po- sition of the Montagne Noire during the early Famen- nian (Dineley, 1984; Sandberg et al., 1988), the influ- ence of variations of precession is most intense (De Boer and Smith, 1994; Schwarzacher, 1993) and is presumed to dominate the other orbital parameters. But cycle duration is at least partly below the Nyquist fre- quency and cannot be singled out in our examples. On the other hand, the eccentricity cycles do not show any significant change through time—while others did— and are found frequently dominating all other cyclic- ities throughout the geological record. The major fre- Table 1.—Number of cycles and duration of conodont biozones under consideration. Conodont zone Cycles Duration (ka) Early triangularis zone 0.5 50 Middle triangularis zone 1.5 150 Late triangularis zone De) 250 Early crepida zone 5) 500 Middle crepida zone 6 600 quencies of eccentricity are the 0.1 Ma and the 0.413 Ma signals one of which—the 0.1 Ma signal—is well known to be amplified by the albedo-temperature and moisture-ice mass feedback system (Einsele and Rick- en, 1991), which itself triggers surface water produc- tivity. Otherwise, the sixteen cycles we were able to extract from our data (Text-fig. 2) amount to a duration of about 6.5 Ma if formed by the 0.413 Ma signal; this corresponds to about two-thirds of total Famen- nian duration as measured with isotopic data (e.g., Claoué-Long er al., 1992) and is therefore not reason- ably considered the dominant frequency. When com- pared to the results of Tucker et al. (1998) who esti- mated the duration of the Famennian to about 14.5 Ma, a similar unbalanced and improbable ratio in duration has to be assumed. If the above argument proves cor- rect, the cyclicity originates in the 0.1 Ma Milankov- itch cycle, and produces a weak signal in our sedi- mentary sequence that is somehow elevated signifi- cantly above depositional background noise (Tucker eft al.,, 1998; tis. b); CORRELATION OF CONODONT STRATIGRAPHY AND CYCLOSTRATIGRAPHY In the stratigraphic interval between the Frasnian/ Famennian boundary and the upper limit of the Middle crepida Zone 15.5 cycles can be recognized (Text-fig. 2). The distribution of cycles between the individual conodont zones in both sections is equal and allows esumation of zonal duration (Table 1). The distribution of time between the individual co- nodont zones is highly unequal, which contrasts to the assumption of Sandberg and Ziegler (1996) of almost equal durations of conodont zones throughout the Fa- mennian. Only the Early and Middle crepida Zones conform to the estimates of the above authors con- cerning their durations, while the complete triangula- ris Zone corresponds in duration to a single subzone. Especially, the duration of the Early triangularis Zone (50 ka) is exceptionally short when compared to its presumed duration of 0.5 Ma. This fact can be caused by the presence of a hiatus in the Coumiac section around the Frasnian-Famennian boundary (Schindler, 1990; Schiilke, 1995, 1999b) and, consequently, a lack TIMING OF CONODONT EVOLUTION: SCHULKE et al. 179 of data which may represent a certain interval of non- deposition. On the other hand, a comparable hiatus has not been observed in the La Serre Trench C section. Therefore, we assume this layer does not represent a considerable amount of time (comp. Klapper, 1997), although this timespan is extraordinarily important to the recovery of conodont fauna. EVOLUTION AND TIME MEASUREMENT The main question raised by our results is what in- fluence evolutionary rates exert on the time scale of biostratigraphical units used for the subdivision of rock sequences. In this case study, an extraordinary evolutionary situation with the mass extinction at the Frasnian/Famennian boundary forms the starting point of the re-differentiation of conodonts in the early Fa- mennian. Palmatolepis, which nearly became extinct during the Kellwasser event save for a single species (e.g., Sandberg et al., 1988; Ziegler and Sandberg, 1990; Klapper et al., 1993; Schiilke, 1995), produced an evolutionary outburst that gave rise to as many as 19 species in the stratigraphical interval under inves- tigation (Schiilke, 1999a). Two major phases of species differentiation can be differentiated (Schiilke, 1995, 1999b): (1) during Middle and Late triangularis Zones, and (2) at the beginning of the Middle crepida Zone. Between these phases only gradual change oc- curs among the species of Palmatolepis; this is attri- buted to subspecific level, because no evident y- branched speciation process can be singled out (Schiil- ke, 1995, 1999a, 2003). The two intervals with in- creased evolutionary rates correspond to the T/R pairs of the third-order cycles following Johnson et al. (1985) (Schiilke, 2003). Other early Famennian co- nodont genera (Polygnathus, Ancyrognathus, Icriodus) do not show a comparable evolutionary outburst, al- though transformational (intraspecific) morphological changes correspond in timing with the diversification phases in Palmatolepis (Schiilke, 2003). On the basis of the facts above several conclusions can be drawn: (1) Large-scale evolutionary change in conodonts, best shown by an almost complete faunal turnover in Palmatolepis, coincides with times of large- scale sea level fluctuations. (2) During the faunal turnover phases, the rate of de- velopment of new morphologies is extremly high due to increased selectional stresses (Schiilke, 2003). In addition, new characters do not appear at precisely the same time in different species, but at various levels within a short period. Conse- quently, this period can be subdivided into a va- riety of zonal units. On the other hand, the “‘sta- sis’ phases between faunal turnovers do not pro- vide the stratigrapher with a wide variety of newly developed characters and are therefore less well subdivided, although they may represent longer time intervals. A respective turnover phase, re- leased by the faunal recovery after the Kellwasser mass extinction and the third-order T/R couplet in the basal Famennian, produces as much as three zonal boundaries (Early/Middle triangularis Zone, Middle/Late triangularis Zone, Late triangularis/ Early crepida Zone). (3) In contrast, large-scale ecological fluctuation phas- es and the subsequent evolutionary changes can happen in such a short time interval that several new morphologies appear at or nearly at the same time. It would be unreasonable to use this spec- trum of new forms to create extremely short bio- zones. In most cases, a single zonal boundary pro- duced by such circumstances can be recognized by several species and is consequently very precise. An example of this is the T/R pair at the beginning of the Middle crepida Zone, which is marked by a variety of species having their first appearance at or near the zonal boundary between the Early and Middle crepida Zones. In our study, we focused on the recovery of cono- donts after the Kellwasser mass extinction, to which our data are able to contribute new estimates about its timing. Several authors (e.g., Morrow and Sandberg, 1996; Schiilke, 1998) have focused on this topic and came to nearly identical results. The first recovery of a conodont fauna is presumed by them to be finished in the middle part of the Late triangularis Zone. Schiil- ke (1998) subdivided the complete process into two parts following the terms of Harries and Kauffman (1990), Kauffman and Erwin (1995), and Kauffman and Harries (1996). The “survival phase” is restricted to the lower two-thirds of the Early triangularis Zone. The “recovery phase,’ consequently, ranges from the upper part of the Early triangularis Zone into the mid- dle of the Late triangularis Zone. Based on estima- tions of average conodont zonal duration, the time elapsed in this process amounts to about | Ma (Schiil- ke, 1998) which agrees with the statement of Kauff- man and Erwin (1995, p. 16), that “recovery intervals ... rarely last more than 1—2 Ma.”” Our sequence strat- igraphical results indicate a duration of conodont re- covery after mass extinction of about 300-350 ka (compare Table 1) with a survival phase less than 50 ka, which is far more rapid than expected. This fact makes conodonts remarkable when compared to other taxa and their recovery intervals, especially those in- volved in the Kellwasser mass extinction, whose re- 180 BULLETIN 369 coveries were delayed until the beginning of the Mid- dle crepida Zone (Schiilke, 1997b, 1998, which see for further literature). In fact, estimates on the duration of recovery inter- vals after mass extinctions are tested against an inde- pendent chronological time scale for the first time in this study. Therefore, nothing can be said as to whether conodonts reveal incomparable high evolutionary rates or not, since ecologically similar organisms throughout the Phanerozoic have not yet been studied like cono- donts, and the contemporaneous basal Famennian groups surely exhibit different lifetime strategies. CONCLUSIONS Carbonate sedimentation on the drowned Montagne Noire carbonate platform in the basal Famennian was probably triggered by the 0.1 Ma precession cycle. The cyclicity signal retrieved by a time series analysis is relatively weak, but its amplitude rises distinctively above all other waveforms. It is most important that, in both sections under investigation, the same number of cycles is developed in the respective conodont zones; this underpins the assumption of orbital forcing. The cyclicity forms a true and repetitive chronolog- ical signal that allows a test of conodont zonal dura- tions within the interval under consideration. This test shows that zones are not equal in duration, which con- trasts with earlier estimations. Immediately after the Kellwasser mass extinction at the Frasnian/Famennian boundary, evolutionary rates were extremely high, so that it is possible to gain high zonal resolution. In con- trast, when syn- and autecological conditions are large- ly stable, evolutionary rates are comparatively low, which results in less biostratigraphical resolution. Pur- ther studies are in progress to analyze the Montagne Noire sections throughout the whole Famennian to de- termine whether the above telescoping of conodont zonal durations demonstrated here is exceptional, due to the faunal recovery after mass extinction, or wheth- er all radiations following minor ecological changes produce similar results. REFERENCES’ CITED Becker, R.T. 1993. Stratigraphische Gliederung und Ammonoideen-Faunen im Nehdenium (Oberdevon H) von Europa und Nordaf- rika. 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Terra Nostra, vol. 97/6, p. 128. Young, G.C. 1987. Devonian paleontological data and the Armorica problem. Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 60, pp. 283-304. Ziegler, W., and Lane, H.R. 1987. Cycles in conodont evolution from Devonian to mid-Car- boniferous. in Palaeobiology of conodonts. R.J. Aldridge, ed., Ellis Howard, Chichester, pp. 147-163. Ziegler, W., and Sandberg, C.A. 1990. The Late Devonian standard conodont zonation. Courier Forschungsinstitut Senckenberg, vol. 121, pp. 1-115. 1998. Devonian high resolution conodont biochronology. Sev- enth International Conodont Symposium held in Europe (ECOS VIL), Abstract Book, pp. 127-128. OSAGEAN TYPE SECTIONS: LANE et al. 183 THE TYPE SECTION OF THE OSAGEAN SERIES (MISSISSIPPIAN SUBSYSTEM), WEST-CENTRAL MISSOURI, U. S. A. H. RICHARD LANE Program Director, Geology and Paleontology Directorate for Geosciences, National Science Foundation Arlington, Virginia 22230, U.S. A. hlane @nsf.gov PAUL L. BRENCKLE Consultant | Whistler Point Road Westport, Massachusetts 02790, U. S. A. saltwaterfarm 1 @cs.com JOHN EF BAESEMANN 1400 Riveredge Drive Kent, Ohio 44240, U. S. A. jfbaesemann @aol.com ABSTRACT The Osagean Series is one of four divisions of the Mississippian Subsystem in North America. Although first described in the latter part of the nineteenth century from truncated outcrops along the Osage River in west-central Missouri, the type Osage has virtually been ignored by stratigraphers, who now define the Osagean on rock and fossil successions exposed in the Mississippi River Valley. This paper revisits the principal reference sections for the type Osage and describes their lithologies, conodonts and calcareous foraminifers and algae. Diagnostic conodonts are limited to the mudzistriatus Zone (Faunal Unit 3B) that correlates to the lower part of the Burlington Limestone and facies-equivalent Fern Glen beds in the Mississippi River Valley. Calcareous microfossils are rare but share elements in common with the type Mississippian, including Rectogranuliferella godini that is reported for the first time in North America. INTRODUCTION The urgent need for establishing boundary strato- types within the Carboniferous (e.g., Heckel, 1999, 2001: Sevastopulo et al., 2001; Villa, 2001; Chuva- shov, 2002a,b) has led to the reexamination of regional series and stages to find suitable levels for global cor- relation. In 2001, the Carboniferous Subcommission (SCCS) sponsored a field excursion to the Mississippi River Valley (Heckel, in press) to acquaint the inter- national geologic community with type sections of the Mississippian, including the Osagean Series. Although this series is understood in terms of outcrops in the Mississippi River Valley, its name and original de- scription come from an area in west-central Missouri that has been little studied. This paper describes sec- tions and microfossils from these latter Osagean beds and relates them to the better known Mississippi River Valley and other international standard stratigraphic successions of the same age. Some of these results have been summarized previously in an informal Car- boniterous Subcommission guidebook (Lane and Brenckle, 1981) as part of a meeting of a SCCS/SEPM Working Group on the Mississippian of the U. S. A. ACKNOWLEDGMENTS We acknowledge the field assistance of Gilbert Klapper in describing and sampling the exposures dis- cussed in this paper and we thank John Groves, Uni- versity of Northern Iowa, and John Repetski, United States Geological Survey, for reviewing the manu- script. Luc Hance of the Carmeuse Group, Belgium, supplied critical information for interpreting the fora- miniferal systematics. 184 BULLETIN 369 MISSOURI MB sy. cuir counry Text-figure 1.—Locality map of the three sections described and sampled for this report. Osceola is located in the center of St. Clair County HISTORICAL BACKGROUND H. S. Williams (1891, p. 169, 172, 265) introduced the term ““Osage Group” as one of three divisions of his Mississippian Series and named it for outcrops along the Osage River in west-central Missouri, al- though no type section was designated (Text-fig. 1). He included the Burlington and Keokuk limestones in the group because he believed faunas from the two formations were present along the river. Keyes (1893, p. 60) noted, however, that the Keokuk was absent along the entire Osage River and proposed (p. 59) the substitute term “Augusta Limestone” [Group] for the Burlington and Keokuk limestones of southeastern Iowa. He (Keyes, 1895) later emended the definition to include the Warsaw Formation at the top of the Au- gusta. The inadequacies of the type Osage notwith- standing, Weller (1898) and Van Tuyl (1925) promoted use of the term “Osage” because of its priority. The name gained wide acceptance throughout North Amer- ica and has been used as a serial division (Osagean) of the Mississippian Subsystem since the publication of Ulrich (1911), even though its definition conforms more closely to the concept of the Augusta Group than to the time-stratigraphic interval represented in the type area along the Osage River. Witzke er al. (1990, p. 15) reintroduced the term Augusta as a lithostrati- graphic grouping for the Burlington-Warsaw interval across lowa and into Nebraska. Through the years, the concept of the Osagean has been modified in both west-central Missouri and the Mississippi River Valley (Text-fig. 2). Ulrich (1911) lowered the base of the Osagean in the Mississippi River Valley to include the Fern Glen Formation of Weller (1906), and the dolomitic limestone beds orig- inally included in the lower Fern Glen have been re- named the Meppen Limestone (Willman er al., 1975). Moore (1928) placed his Sedalia Formation of west- central Missouri at the base of the Osagean and mis- takenly correlated the lower part of that formation to the lower Fern Glen (=Meppen Limestone). Spreng (1952) and Beveridge and Clark (1952) demonstrated that the upper part of Moore’s Sedalia was equivalent to the Northview Shale (Weller, 1906) and Pierson Limestone (Weller, 1906) to the south. They restricted the Sedalia to beds beneath the Northview and placed the Kinderhookian-Osagean boundary at the North- view-Pierson contact. Northview conodonts (Thomp- son and Fellows, 1970), however, are equivalent to the earliest Osagean conodont punctatus Zone (Faunal Unit 2; Text-figs. 2, 3), suggesting that the Kinder- hookian-Osagean boundary actually lies at the North- view-Sedalia contact. The dark shales of the North- view probably represent a basal transgressive unit of the Osagean Series. Kaiser (1950) in his review of the type Osage of west-central Missouri stated that the most complete section is at the abandoned Bullard-Hunt Quarry (Kai- ser’s Locality 56), about one mile west of the town of Osceola. This locality now serves as the principal ref- erence section for the Osage Group. Two of our mea- OSAGEAN TYPE SECTIONS: LANE et al. FORAMINIFERAL ASSEMBLAGES (MIDCONTINENT) NORTH AMERICAN SERIES EUROPEAN SERIES Lower Warsaw- Keokuk faunas (Brenckle et al., 1974, 1982; Kammer et al., 1990) Endothyra-“Priscella” Rectogranuliferella godini- Mametella chautauquae Gilmore City faunas (Brenckle & Groves, 1987; Woodson, 1993) TOURNAISIAN (part) punctatus isosticha Upper crenulata KINDERHOOK- VANA(p art) Septaglomospiranella- Prochernyshinella? CONODONT ZONES 1S burlingtonens multistriatus poe | communis carinus pom fo 3 3 MISSISSIPPI RIVER VALLEY CONODONT FAUNAL UNITS Northview ae 7 B A 1G 1F Text-figure 2.—Osagean microfossil zones/assemblages and their relation to North American Midcontinent formations and western European series. Diagnostic conodonts, belonging to the mudtistriatus Zone, are limited to the lower part of the Burlington Limestone in the type Osage. The upper part of the Burlington in this area is placed within the /awtus and lanei conodont zones (Faunal Units 4A and 4B) by stratigraphic position. The Gilmore City foraminifers are assumed to fit within the hiatus at the Kinderhookian-Osagean boundary in the Mississippi River Valley (Brenckle and Groves, 1987), even though this assemblage cannot be correlated directly to either the Mississippi River Valley or the type Osage because there are no diagnostic foraminifers in common. The Septaglomospiranella-Prochernyshinella? foraminiferal assemblage comes from occurrences listed in Lane and Brenckle (in press, fig. 8); the Rectogranuliferella godini-Mametella chautauquae assemblage from occurrences discussed in this paper; and the Endothyra-*Priscella” assemblage is from Witzke et al. (1990) and Lane and Brenckle (in press, fig. 8). sured sections are located within the quarry and a third is nearby (Text-fig. 1). BIOSTRATIGRAPHY CONODONTS Although conodonts are rare and low in diversity in our measured sections, the fauna permits correlation of the type Osage to the Mississippi River Valley cono- dont succession (Text-fig. 2). At the Osceola North Roadcut (see Text-fig. 4), a late Kinderhookian cono- dont fauna containing Siphonodella sp. and Elictog- nathus laceratus was recovered in the Sedalia. Be- cause of poor preservation, the fauna is assigned ques- tionably to the isosticha—Upper crenulata Zone of Sandberg er al. (1978) [=faunal units IF and 1G, Text- fig. 2]. Samples from the overlying Northview and Pierson did not yield conodonts. However, in south- western Missouri, the Northview contains conodonts (Thompson and Fellows, 1970) indicative of the ear- liest Osagean punctatus Zone (Faunal Unit 2) and be- comes as young as the communis carinus Zone (Faunal Unit 3A). In northeastern Oklahoma, the base of the overlying Pierson is as old as the punctatus Zone and the top becomes as young as the bulbosus Zone (Fau- nal Unit 6). At the type Osage, the lower part of the Burlington Limestone contains conodonts belonging to No Oo a Z ~ OSAGEAN TYPE SECTIONS: LANE ef al. 187 the multistriatus Zone (Faunal Unit 3B) and, thus is equivalent to part of the Pierson to the south. The re- mainder of the Burlington in the type Osage lacks di- agnostic conodonts but is placed tentatively within co- nodont Faunal Unit 4 (Text-fig. 2) on stratigraphic po- sition. Representative conodonts are illustrated on Plate 1. CALCAREOUS MICROFOSSILS Early Osagean foraminifers and algae are sparse in this study as is typical in most of the North American Midcontinent (Brenckle and Groves, 1987). Of a total of 45 samples collected, only five contained calcareous microfossils—all within the Burlington Limestone— and the diversity and total number of specimens are low. The Burlington, although partly dolomitized, re- tains its primary crinoidal-bryozoan grain-supported texture whereas the subjacent Pierson, Northview and Sedalia formations (see Text-fig. 4) have dolomitic and siliciclastic lithologies that are unfavorable for recov- ery of calcareous microfossils. Multilocular foramini- fers are confined to approximately the same interval represented by samples 17 and 18 at the Osceola North Roadcut (see Text-fig. 4) and samples 8 and 11 at the Bullard-Hunt Quarry Section II (see Text-fig. 6). For- aminifers in this interval include Rectogranuliferella godini, questionable Granuliferella and indeterminate forms along with the aoujgaliin alga Stacheoides? sp. A second microfossiliferous horizon (sample 16, Bul- lard-Hunt Quarry Section IT) contains only the simple, long-ranging foraminifer Earlandia. The Burlington in the Mississippi River Valley has the same primary lithology as its counterpart in the type Osage and, along with the underlying Fern Glen and Meppen formations, also contains few calcareous microfossils. Specimens of Earlandia occur through- out the early Osagean there but potentially diagnostic multilocular forms are rare. Rectogranuliferella godini has been found only in the Fern Glen at a single lo- cality, Chautauqua West (Brenckle, 1977), along the Mississippi River in association with indeterminate en- dothyrids s. / and aoujgaliin algae (Mametella chau- tauquae Brenckle, 1977; Stacheoides sp.), whereas En- dothyra and **Priscella” spp. appear in the upper Bur- lington (Witzke et al., 1990; Lane and Brenckle, in press). These occurrences are the basis for some of the early Osagean foraminiferal assemblages shown in Text-figure 2. The meager recoveries contrast mark- edly with the relatively abundant and diverse Early Mississippian North American faunas found in north- central Iowa (Zeller, 1950; Brenckle and Groves, 1987; Woodson, 1993) and west of the Transcontinental Arch (Zeller, 1957; McKay and Green, 1963; Skipp, 1969; Brenckle, 1973; Mamet, 1976; Mamet ef al., 1986). PLATE 1 Specimens are reposited at the University of lowa Paleontology repository (SUI). Figure 1, 2, 12, 13. Polygnathus communis communis Branson and Mehl, P-elements. 1, 2. Upper (<101) and lower (X88) views of SUI-95350, respectively, Burlington Limestone (Bullard-Hunt Quarry I, Sample 11). 12, 13, Lower (<117) and upper (103) views of SUI-95351, respectively, Burlington Limestone (Osceola North Roadcut, Sample 12). 3. Ozarkodina sp. Lateral view (*89) of SUI-95352 (O-element), Burlington Limestone (Bullard-Hunt Quarry I, Sample 8). 4, 5. Gnathodus typicus Cooper. Upper (68) and lower (62) views respectively of P element SUI-95353, respectively, Bur- lington Limestone (Osceola North Roadcut, Sample 9). 6. Siphonodella sp. Upper view (X89) of P element SUI-95354, Sedalia Formation (Osceola North Roadcut, Sample 2). 7, 11. Pseudopolygnathus multistriatus Mehl and Thomas (Morphotype 2) (P element). Upper (75) and lower (80) views, respectively, of SUI-95355, Burlington Limestone (Bullard-Hunt Quarry I, Sample 8). 8. Spathognathodus pulcher (Branson and Mehl). Lateral view (86) of P element SUI-95356, Burlington Limestone (Bullard- Hunt Quarry I, Sample 8). 9. Idioprioniodus furnishi (Rexroad). Outer lateral view (*46) of O element SUI-95357, Burlington Limestone (Bullard-Hunt Quarry II, Sample 3). 10. Elictognathus laceratus (Branson and Mehl). Outer lateral view (*102) of O element SUI-95358, Sedalia Formation (Osceola North Roadcut, Sample 2). 14. Unassigned B—element. Inner lateral view (64) of SUI-95359, Burlington Limestone (Osceola North Roadcut, Sam- ple 9). 15, 16. Polygnathus communis subsp. indet. Lower (96) and upper (88) views respectively of P element SUI-95360, Burlington Limestone (Osceola North Roadcut, Sample 15). 188 BULLETIN 369 Range of Osagean Conodonts Fm |Lithology | F-U. Midcontinent Keokuk [ cedarFon | ite yo) IW B aan H fe fo m7pecnisl ae ain aw oO fed) ® el = aD Ow ale MN il ‘ x iS ial a al | Text-figure 3. Ranges of important conodonts in the Osagean Series of the North American Midcontinent. The formations shown are from the Mississippi River Valley where Faunal Units 2 and lower 3A are missing, but these units are found in the Osagean of southwestern Missouri. Conodonts species are: 1. Siphonodella isosticha, 2. Gnathodus punctatus; 3. Gnathodus delicatus; 4. Gnathodus praedelicatus; 5.Gnathodus semiglaber; 6. Gnathodus typicus; 7. Polygnathus communis communis, 8. Polygnathus communis carinus, 9. Staurognathus OSAGEAN TYPE SECTIONS: LANE et al. 189 SYSTEMATIC PALEONTOLOGY Class FORAMINIFERA d’Orbigny, 1826 Order FUSULINIDA Wedekind, 1937 Superfamily ENDOTHYRACEA Brady, 1884 Family ENDOTHYRIDAE Brady, 1884 Genus RECTOGRANULIFERELLA Conil and Lys in Mansy et al., 1989 Type species.—Palaeospiroplectammina? godini (Conil, 1980). Rectogranuliferella godini (Conil, 1980) Plate 2, figures 1-8 Spiroplectamminoides [=Palaeospiroplectammina] cf. S. parva (Chernysheva), Skipp, 1969, p. 228, pl. 24, figs. 9, 10, 12. Palaeospiroplectammina? godini Conil, 1980, pp. 45—46, pl. 1, figs. 19, 20. Palaeospiroplectammina aff. P. parva (Chernysheva), Lane and Br- enckle, 1981, pl. 2, figs. 1-5. Rectogranuliferella godini (Conil), Conil and Lys in Mansy et al., 1989, p. 139, pl. 6, figs. 10-14; Lane and Brenckle, in press, fig. 8. Measurements (n = 9).—Length: 710-865 jm; width, biserial chambers: 295—355 jm; thickness, bis- erial chambers: 275—300 j1m; diameter, coiled portion: 355-425 jm; diameter, coiled portion/length: 0.41— 0.50; number of volutions, coiled portion: about 2; number of chambers in last volution: 7; number of chambers in biserial area: 5—7; interior diameter of proloculus: 55-60 jm; wall thickness of biserial chambers: 20—30 p.m. Description.—Test is composed of a relatively large, slightly skew-coiled immature stage followed by a lin- early arranged set of biserial chambers. Volutions in the coiled portion expand slowly and the chambers are slightly to moderately inflated with well developed septation. Biserial chambers inflate very slowly during growth so that the sides of the test appear nearly straight-sided in sagittal section. Their septa that ex- tend about halfway across to the opposite wall are slightly convex and may be thickened along the ends. i Wall is coarsely granular-agglutinated. Aperture is a basal slit at the end of the last septum. Discussion.—Rectogranuliferella is a monotypic genus, most of whose specimens have formerly been placed in Palaeospiroplectammina because of obvious morphologic similarities. Conil and Lys (in Mansy et al., 1989) distinguished Rectogranuliferella on the “endothyrin” chamber shape in the coiled portion of the test and on the lighter-colored, coarsely granular- agglutinated wall. They likened the wall structure to that of Granuliferella in contrast to the darker, finer- grained test found in typical Palaeospiroplectammina. The palaeospiroplectamminin wall, however, is not al- ways homogeneously fine-grained, and the two genera may be confused in specimens where the coiled por- tion is not well oriented. The Midcontinent specimens upon which the above description is based were originally thought (Lane and Brenckle, 1981) to be related to Palaeospiroplectam- mina parva (Chernysheva, 1940) in the size of the coiled portion relative to the length of the test and in the number and arrangement of the biserial chambers. They differed in having larger dimensions and more numerous chambers in the last volution of the coiled stage. That assignment is reevaluated in light of the R. godini specimens illustrated in Conil (1980) and Man- sy et al. (1989) that are similar in size, chamber count and wall structure to the Midcontinent specimens. Skipp’s (1969) material described as Spiroplectammi- noides ct. S. parva is also herein reassigned to R. god- ini for the same reasons. Occurrence.—The R. godini specimens of Conil (1980) and Mansy et al. (1989) are found in early late Tournaisian beds (Belgian foraminiferal zone Cf2) at Avesnois, France. North American examples come from similar age rocks, including the early Osagean Burlington Limestone of west-central Missouri and Fern Glen Limestone of western Illinois in the Mid- continent and the early Osagean upper Whitmore Wash, Thunder Springs and lower Mooney Falls mem- bers of the Redwall Limestone in Arizona (Skipp, 1969, foraminiferal zone 2B). achorarius; 10. Pseudopolygnathus multistriatus; 11. Gnathodus hamatus; 12. Pseudopolygnathus oxypageus; 13. Pseudopolygnathus nudus: 14. Bactrognathus hamatus; 15. Bactrognathus minutus; 16. Gnathodus antetexanus; 17. Scaliognathus dockali; 18. Scaliognathus praean- choralis; 19. Doliognathus dubius; 20. Staurognathus cruciformis, 21. Doliognathus latus; 22. Pseudopolygnathus pinnatus, 23. Bactrognathus excavatus; 24. Scaliognathus anchoralis europensis; 25. Scaliognathus anchoralis anchoralis; 26. Bactrognathus distortus; 27. Bactrognathus lanei; 28. Gnathodus cuneiformis; 29. Polygnathus mehli; 30. Eotaphrus burlingtonensis; 31.Gnathodus pseudosemiglaber, 32. Gnathodus bulbosus; 33. Gnathodus texanus; 34. ‘“Spathognathodus” deflexus; 35. Taphrognathus varians; 36. ‘*Spathognathodus” coalescens, 37. Apa- tognathus pinnatus. The faunal unit scheme is a refinement of those proposed in Lane (1974, 1978) and Lane and Ormiston (1982); it will be published in Lane and Brenckle (in press). Abbreviations: Fm = formation; EU. = conodont faunal unit. Dolby Ck.(Creek), Haight Creek and Cedar Fork are members of the Burlington Limestone. 190 BULLETIN 369 PLATE 2 Rectogranuliferella godini (Conil, 1980), approximately 95. Specimens 3 and 8 are from the Fern Glen Limestone, Chautauqua West Section, Jersey County, Illinois, described in Brenckle (1977); other specimens are from the Burlington Limestone outcrops described in this paper. Specimens reposited in the National Museum of Natural History, Smithsonian Institution, Washington, DC; repository numbers (USNM) are 1n parentheses. Figure 1. (USNM 519336), near-axial section, Bullard-Hunt Quarry H, Sample 9 2. (USNM 519337), near-axial section, Osceola North Roadcut, Sample 17. 3. (USNM 519338), sagittal section, Chautauqua West, Sample 9. 4. (USNM 519339), oblique-axial section, Bullard-Hunt Quarry II, Sample 9 5. (USNM 519340), near-axial section of juvenarium, Bullard-Hunt Quarry H, Sample 9. 6. (USNM 519341), tangential-sagittal section, Bullard-Hunt Quarry I], Sample 9. (USNM 519342), tangential-sagittal section, Bullard-Hunt Quarry II, Sample 9 8. (USNM 519343), sagittal section, Chautauqua West, Sample 10. OSAGEAN TYPE SECTIONS: LANE et al. 19] REFERENCES CITED Beveridge, T.R., and Clark, E.L. 1952. A revision of the Early Mississippian nomenclature in western Missouri. Guidebook Sixteenth Regional Field Conference. Kansas Geological Society, pp. 71-79. Brady, H.B. 1884. Report on the Foraminifera dredged by HMS Challenger, during the years 1873-1876. Rept. Scientific Results Ex- plor. Voyage HMS Challenger, Zoology, vol. 9, pp. 1 814. Brenckle, P.L. 1973. Smaller Mississippian and Lower Pennsylvanian calcare- ous foraminifers from Nevada. Cushman Foundation for Foraminiferal Research, Special Publication No. 11, 82 pp.. 10 pls. 1977. Mametella, A new genus of calcareous red Algae (?) of Mississippian age in North America. Journal of Paleon- tology, vol. 51, no. 2, pp. 250—255, 1 pl. Brenckle, P.L., and Groves, J.R. 1987. Calcareous foraminifers from the Humboldt Oolite of Iowa. Key to early Osagean (Mississippian) correlations between eastern and western North America: Palaios, vol. 1, pp. 561-581, 5 pls. [imprint 1986]. Brenckle, P.L., Lane, H.R., and Collinson, C. 1974. Progress toward reconciliation of Lower Mississippian co- nodont and foraminiferal zonations. Geology, vol. 2, no. 9, pp. 433-436, 1 pl. Brenckle, P.L., Marshall, F.C., Waller, S.F., and Wilhelm, M. 1982. Calcareous microfossils from the Keokuk Limestone and adjacent formations, upper Mississippi River Valley: their meaning for North American and intercontinental corre- lations. Geologica et Palaeontologica, vol. 15, pp. 47-88, 10 pls. Chernysheva, N.E. 1940. On the stratigraphy of the Lower Carboniferous Forami- nifera in the Makorovski district of the south Urals. So- ciety of Moscow Naturalists Bulletin, new series, vol. 48, Geol. Sec. vol. 18, nos. 5—6, pp. 113-135, 2 pl. [in Rus- sian]. Chuvashoy, B.I., ed. 2002a. Guidebook for Uralian Carboniferous geologic excur- sions: Part 1—southern Uralian excursion. /n Internation- al symposium on biostratigraphy and boundaries of east- ern European Carboniferous stages. Inst. geol. i geokhim. UrO RAN, Ekaterinburg, 72 pp. 2002b. Guidebook for Uralian Carboniferous geologic excur- sions: Part 2—mid-Uralian excursion. /n International symposium on biostratigraphy and boundaries of eastern European Carboniferous stages. Inst. geol. i geokhim. UrO RAN, Ekaterinburg, 104 pp. Conil, R. 1980. Note sur quelques foraminiféres du Strunien et du Din- antien d’Europe occidentale. Annales de la Société Géo- logique de Belgique, vol. 103, pp. 43-53, 2 pls. Heckel, P.H. 1999. Middle and Upper Pennsylvanian (Upper Carboniferous) cyclothem succession in Midcontinent Basin. U-S.A., Field Trip No. 8, 14th International Congress on the Car- boniferous-Permian, Calgary, Canada, August 1999: Kan- sas Geological Survey Open-file Report 99-27, 236 pp. 2001. Chairman’s column. Newsletter on Carboniferous Stratig- raphy, vol. 19, pp. 1-3. In press. Stratigraphy and biostratigraphy of the Mississippian Subsystem (Carboniferous System) in its type region, the Mississippi River Valley of Illinois, Missouri, and Iowa. International Union of Geological Sciences, Subcommis- sion on Carboniferous Stratigraphy Guidebook for Field Conference, September 8-13, 2001. Illinois State Geolog- ical Survey Guidebook. Kammer, T.W., Brenckle, P.L., Carter, J.L., and Ausich, W.I. 1990. Redefinition of the Osagean-Meramecian boundary in the Mississippian stratotype regions. Palaios, vol. 5, pp. 414— 431. Kaiser, C.P. 1950. Stratigraphy of Lower Mississippian rocks in southwest- ern Missouri. Bulletin of the American Association of Pe- troleum Geologists, vol. 34, pp. 2133-2172. Keyes, C.R. 1893. The geological formations of lowa. lowa Geological Sur- vey, vol. 1, pp. 13-144. 1895. Geology of Lee County and Geology of Des Moines County. lowa Geological Survey, Annual Report, vol. 3, pp. 305—492. Lane, H.R. 1974. Mississippian of southeastern New Mexico and west Tex- a wedge-on-wedge relation. Bulletin of the American Association of Petroleum Geologists, vol. 58, pp. 269— 282. 1978. The Burlington Shelf (Mississippian): north-central Unit- ed States. Geologica et Palaeontologica, vol. 12, pp. 165— 176. Lane, H.R., and Brenckle, P.L. 1981. The type Osage. /n Mississippian stratotypes. C. Collin- son, J.W. Baxter, R.D. Norby, H.R. Lane, and P-L. Brenc- kle. Hlinois State Geological Survey Guidebook, 15" North-Central Geological Society of America Meeting, Ames, Iowa, pp. 1-12, 2 pls. as In press. Type Mississippian subdivisions and biostratigraphic succession. in Stratigraphy and biostratigraphy of the Mis- sissippian Subsystem (Carboniferous System) in its type region, the Mississippi River Valley of Illinois, Missouri, and lowa. P.H. Heckel, ed. International Union of Geo- logical Sciences, Subcommission on Carboniferous Stra- tigraphy Guidebook for Field Conference, September 8— 13, 2001. Hlinois State Geological Survey Guidebook. Lane, H.R., and Ormiston, A.O. 1982. Waulsortian facies, Sacramento Mountains, New Mexico. Jn Symposium on the paleoenvironmental setting and dis- tribution of the Waulsortian facies. K. Bolton, H.R. Lane, and D.V. LeMone, eds., El Paso Geological Society and University of Texas at El Paso, International Field Semi- nar Guide, March 2-6, 1982, pp. 115-182. Mamet, B.L. 1976. An atlas of microfacies in Carboniferous carbonates of the Canadian Cordillera. Geological Survey of Canada, Bulletin 255, 131 pp., 95 pls. Mamet, B.L., Bamber, E.W., and Macqueen, R.W. 1986. Microfacies of the Lower Carboniferous Banff Formation and Rundle Group, Monkman Pass map area, northeastern British Columbia. Geological Survey of Canada, Bulletin 353, 93 pp., 18 pls. Mansy, J.L., Conil, R., Meilliez, F., Khatir, A., Delcambre, B., Groessens, E., Lys, M., Poty, E., Swennen, R., Tren- tesaux, A., and Weyant, M. 1989. Nouvelles données stratigraphiques et structurales sur le Dinantien dans l’Avesnois. Annales de la Société Géo- logique du Nord, vol. 108, pp. 125-142, pls. 6—10. 192 BULLETIN 369 McKay, W., and Green, R. 1963. Mississippian Foraminifera of the southern Canadian Rocky Mountains, Alberta. Research Council of Alberta, Bulletin 10, 77 pp., 12 pls. Moore, R.C. 1928. Early Mississippian formations in Missouri. Missouri Bu- reau of Geology and Mines, vol. 21, pp. 1-283. Orbigny, A.D. d’ 1826. Tableau méthodique de la classe des Céphalopodes. An- nales des Sciences Naturelles, Paris, ser. 1, vol. 7, pp. 245-314. Sandberg, C.A., Ziegler, W., Leuterlitz, K., and Brill, S.M. 1978. Phylogeny, speciation, and zonation of Siphonodella (Conodonta, Upper Devonian and Lower Carboniferous). Newsletters on Stratigraphy, vol. 7, pp. 102—120. Sevastopulo, G., Hance, L., Devuyst, F.X., Coen, M., Hou, H., Tian, S., and Wu, X.H. 2001. Progress report of the working group to establish a bound- ary close to the existing Tournaisian-Visean boundary within the Lower Carboniferous. Newsletter on Carbon- iferous Stratigraphy, vol. 19, pp. 7-8. Skipp, B. 1969. Foraminifera. in History of the Redwall Limestone of northern Arizona. E.D. McKee and R.C. Gutschick, eds., Geological Society of America, Memoir 114, pp. 173- 255, pls. 16-28. Spreng, A.C. 1952. The lower Pierson fauna of west-central Missouri. Guide- book 16th Regional Field Conference, The Kansas Geo- logical Society, pp. 81—86. Thompson, T.L., and Fellows, L.D. 1970. Stratigraphy and conodont biostratigraphy of Kinderhook- ian and Osagean (Lower Mississippian) rocks of south- western Missouri and adjacent areas. Missouri Geological Survey and Water Resources, Report of Investigations 45, 263 pp. Ulrich, E.O. 1911. Revision of the Paleozoic Systems. Geological Society of America Bulletin, vol. 22, pp. 281-680. Van Tuyl, F.M. 1925. The stratigraphy of the Mississippian formations of Iowa. Iowa Geological Survey, Annual Report, vol. 30, pp. 33- 359! Villa, E. 2001. forking group to define a GSSP close to the Moscovian/ Kasimovian boundary. Newsletter on Carboniferous Stra- tigraphy, vol. 19, pp. 8-11. Wedekind, P.R. 1937. Einfiihrung in die grundlagen der historischen geeologie, Band II. Mikrobiostratigraphie die Korallen- und Fora- miniferenzeit. Ferdinand Enke (Stuttgart), 136 pp. Weller, S. 1898. Osage vs. Augusta. American Geologist, vol. 22, pp. 16— 18. 1906. Kinderhook faunal studies—4. Fauna of the Glen Park Limestone. St. Louis Academy of Sciences Transactions, vol. 16, pp. 435-471. Williams, H.S. 1891. Correlation Papers, Devonian and Carboniferous. United States Geological Survey Bulletin 80, pp. 1-279. Willman, H.B., et al. 1975. Handbook of Hlinois Stratigraphy. Illinois State Geolog- ical Survey, Bulletin 95, 261 pp. Witzke, B.J., McKay, R.M., Bunker, B.J., and Woodson, F.J. 1990. Stratigraphy and paleoenvironments of Mississippian stra- ta in Keokuk and Washington counties, southeast Iowa. Iowa Department of Natural Resources, Geological Sur- vey Bureau, Guidebook Series, no. 10, 105 pp. Woodson, F.J. 1993. Early Mississippian calcareous Foraminifera from the lower part of the Gilmore City Formation, north-central Iowa. Ph.D. thesis, University of lowa, lowa City, 83 pp., 6 pls. Zeller, E.J. 1950. Stratigraphic significance of Mississippian endothyroid Foraminifera. University of Kansas Paleontological Con- tributions, Article 4, 23 pp., 6 pls. 1957. Mississippian endothyroid Foraminifera from the Cordil- leran Geosyncline. Journal of Paleontology, vol. 31, pp. 679-704, 8 pls. APPENDIX The following three localities (Text-figs. 4-6) rep- resent the primary reference sections for the Osage Group. They were described and sampled in Novem- ber 1975 by Gilbert Klapper of The University of lowa and the authors. Although the Bullard-Hunt Quarry outcrops were Well exposed and accessible at that time, the Harry S. Truman Reservoir has since flooded all but the upper part of section II. The quarry exposes only part of the Burlington Limestone, which is covered at the base and eroded at the top. A nearby section (Osceola North Roadcut, Text-fig. +), exposes the lower beds of the Burlington and the underlying Pierson, Northview, and Sedalia formations. The Keokuk Limestone and younger Mis- sissippian units are not present in the vicinity of Os- ceola. OSCEOLA NoRTH ROADCUT This outcrop (Text-fig. 4) is located on the north side of County Route B, 1.45 km west of Missouri Highway 13 and just east of the Frisco Railroad tracks (NW%, SW%, NW4, Sec. 17, T38N, R25W, St. Clair County, Missouri). The section begins within the Se- dalia and proceeds through the Northview and Pierson into the Burlington. OSAGEAN TYPE SECTIONS: LANE et al. 193 OSCEOLA NORTH ROADCUT CALCAREOUS METERS eure UNIT CONODONTS MICROFOSSILS ie ©«=«d ? x 1 ! 1 ! (7 x 15 PL, O — 13 O Zz 16 = —12 [a4 10 aw 71 > 13 x (=e) 2 10 x ul x 9 10 Bee ea x x on —_ Yn 6 ~ 7 Ww 6 = 5 ae Le NORTHVIEW : 4 1 x x ) o 210 BULLETIN 369 FUSULINID WALL STRUCTURE: GROVES 211 SYNCHRONOUS PARALLELISM VS. COLLATERAL EVOLUTION As noted earlier, specimens transitional between Profusulinella and Fusulinella are known from nu- merous localities in the United States, Europe, Tian’ Shan’, and northern Thailand, and still others undoubt- edly remain to be discovered. Did the Profusulinella— Fusulinella evolutionary transition occur independent- ly in these widely separated areas, or did it occur only once in a panmictic, global population? The overwhelming bulk of evidence argues against a global population. Fusulinids were benthonic inhab- itants of shallow marine, tropical to subtropical pa- leoenvironments, and they are found most commonly in carbonate or mixed carbonate-siliciclastic litholo- gies. Because of their mode of life and paleoenviron- mental preferences, Pennsylvanian paleoclimate and paleogeography conspired to isolate fusulinid faunas. By late Atokan/late Kashirian time, most major land areas had assembled to form Pangaea, resulting in the closure of the former circumequatorial seaway and the fragmentation of formerly contiguous shallow marine biotopes (Rowley et al., 1985; Ross and Ross, 1985). High latitude land areas were glaciated periodically (Crowell, 1978), presumably with a concomitant cool- ing of adjacent marine shallow waters. Consequently, Pennsylvanian fusulinids were highly provincial. Ma- rine communication between the Midcontinent-An- dean and Eurasian-Arctic faunal realms probably was infrequent and channeled primarily through the mid- paleolatitude Franklinian Geosyncline (Ross, 1967; Ross and Ross, 1985). Given these circumstances, it is remarkable that geographically disjunct populations of advanced profusulinellids apparently underwent identical modifications in wall structure at about the same time. The Profusulinella—Fusulinella evolution- ary transition seems to have occurred independently in South China central Texas | western Eurasia} north Thailand | Japan Cc 3 g : 5 < s x a =| o Ss 3 Q _ = i c (eo) Q o ~ Ss = > =} Q s Shlc = c 3 Q = ~F] % 5 © = = 5 S affs | HP eS eee < = i= 4 oD fe So a= 7) vy F w at EY ~ Oa) Sy as Oil Se ee S Se, SS ss c Q =H lips =) O | S S S| < z a) : 8 A c| & d a 5| 8 3 ae = (= je) oy i oO iS ors ob =} oO 0.25 of the dis- 228 BULLETIN 369 tance between leaf margin and the leaf’s long axis as the criterion for lobe-recognition. Under Hickey’s (1973) definition, models 1, 2, 6, and possibly 7 of Text-figure 10 would described as non-lobed leaves. This would imply that the remaining shape models all exhibit some aspect of the lobate condition (see also Stearn, 1992). Within this larger group, Wolfe’s (1993) definition of pinnate lobation (a line joining the sulci lies ap- proximately parallel to the midrib, or central axis) is similarly restrictive. Only models 10, 13, and 15 of Text-figure 10 are strictly consistent with this defini- tion of the pinnate condition. If Wolfe’s (1993) defi- nition is broadened slightly to admit leaves whose in- tersulcus lines lie at angles between O° and 30° of the central axis, however, models 11 and 14 might be add- ed to this group. As mentioned above, the definition of palmate lo- bation (lobes supported by radial midribs that meet at a common basal point, see Stearn, 1992; Wolfe, 1993) suffers from being based on a different criterion than pinnate lobation. It is therefore possible, in principle, for a leaf to be both palmate and pinnate simultaneous- ly. The resultant ambiguity might be remedied by fo- cusing on the radially directed character of the lobes themselves rather than the nature of their support. Re- gardless, any reasonably specific geometric definition of the palmate character state imposes another set of highly restrictive conditions on the realizable shape range. Results presented in Text-figure 10 suggest that only shapes 4, 5, and 9 meet the palmate criteria. The remaining models (3, 8, 9, and 12) specify a broad boundary area between pinnate and palmate lobation that, at least under Wolfe’s (1993) classification, would be correctly assigned to an undifferentiated lobate sen- su lato category. Taking these results into consideration, an estimate of the boundaries between Wolfe’s (1993) leaf loba- teness shape classes—including the pinnate-palmate distinction—can be quantitatively related to the mod- eled shape plane (Text-fig. 11). By combining text- figures 10 and 11, a table of leaf lobateness can be constructed to guide those wishing to consistently score leaves according to Wolfe’s (1993) leat-lobate- ness classes. In addition, the data derived from such an exercise could be used to further develop and refine the relation between leaf lobateness and environmental state. There are at least two general points worth noting about this example. First, without the geometric for- malism and ability to explore shape transitions that underlies the modeling approach, it seems unlikely that shape-class boundary definitions could be sharpened as quickly as they were in this analysis. The character 10 Palmately 1 Palmately Lobate Lobate 0s al 7 © Nonlobate : Nonlobate a. | ce 4 Ole el = Pinnately 4 + Pinnately >) Lobate 1 a Lobate oD = (s.1) 1 ‘ | (s.1.) a ] | | 0.5 Pinnately Pinnately } | Lobate / Lobate J | 1.50 1.55 1.60 1.65 1.70 -1.0 0.5 00 0.5 10 Eigenshape | Eigenshape 3 Text-figure 11.—Subregions of the leaf-lobateness intermediacy plane that correspond to the character states described by Wolfe (1993). Once these regions have been defined and extended into higher dimensions so that they represent hypervolumes rather than planar regions they can be used to understand the geometry of char- acter-state variation. of the lobate (undifferentiated) region is particularly instructive. In the absence of such shape models, it is doubtful that the character of shapes that did not fit into any of Wolfe’s (1993) three canonical categories could have been recognized as easily. Second, these models make plain the contingent na- ture of many character-state assignments. For example, even though the leaf apex in end-member shapes | (unlobed exemplar) and 5 (palmate exemplar) is sim- ilar—and would be described as acute in both instanc- es (see below)—the transitional model 2 exhibits an attenuated apex. The apparent reversal occurs not be- cause the nature of the tip has changed substantially, but because the nature of other aspects of the shape (in this case the median and basal regions) are chang- ing and forcing a concomitant change in the apical region. This coincidence is primarily due to the limited number and morphological character of Wolfe’s three lobateness exemplar shapes. LEAF BASES Wolfe’s (1993) leaf-base character is complicated by the number of similar exemplars he includes in his illustration (Text-fig. 4). Yet, a scattering of the seven exemplar shapes in the subspace of the first three ei- genshape vectors (representing 99.26% of total shape variance, Text-fig. 12) shows them to be arranged on or close to a plane inclined to the three vector axes. This plane joins the most acute (base characterized by straight sides denoting an angle of less than 90° and coming to a definite point) and cordate (rounded basal lobes extending [basally] below the central axis ter- mination) forms. The first vector axis expresses the relative width of the basal region, the second captures the acute-cordate distinction mentioned above, and the third represents the relative depth of the basal region. LEAF SHAPE MODELS: MACLEOD 229 1:0/—- Eo 05 for | y ¥ a. ss | & 004 wv Vv 5 Vv uv eos v v ve vw ee eS = 0.2 0.6 1.0 14 1.8 -1.0 -0.5 0.0 () 1.0 Eigenshape | Eigenshape 3 Text-figure 12.—Ordination of the three leaf-base shape exem- plars in the space of the three eigenshape vectors; \, = 81.76%, \, = 15.07%: \, = 2.43%). In order to visualize the ordination in three- dimensional space imagine that, relative to plot A, plot B is rotated 90°. Note that this ordination delimits a roughly quadrilateral space within a plane that is inclined at an angle to the three eigenshape vectors. This space contains the coordinate positions for all shapes that can be considered intermediate to the exemplar shapes. Regions of shape variation whose boundaries represent the boundaries of shape variation characteristic of each character state will be found within this quadrate space. [Note: for this analysis Wolfe’s (1993) figures were assumed to represent the entire basal region.] Within this space most of the non-extreme exemplars are ar- rayed along, and slightly above, the line that joints the narrowest and deepest acute and cordate shapes. Using this inclined plane joining the extreme shapes as the most representative shape modeling surface, and deforming that plane slightly into a rectilinear grid, the character of shapes representing linear intermediates between those extremes at known locations within the space of the first three eigenshape vectors can be de- termined. These are shown in Text-figure 13. The interpretation of the modeled shape-transfor- mation plane is both natural and relatively obvious— much more so than the somewhat abstract shape-sub- space scattergrams of Text-figure 12. The most striking shape-related results revealed by these models are dif- ferences in the spatial scope of Wolfe’s (1993) three basal-shape character states. Shape models 1—10 of Text-figure 13 correspond to his definition of acute leaf base morphologies. Hickey’s (1973) classification would distinguish three states within this complex: de- current bases (concave sides, models I—5 of Text-fig. 13), cuneate bases (straight sides, presumably corre- sponding to models intermediate between rows |—5 and 6-10 of Text-fig. 13), and acute bases (convex sides, models 6-10). In a similar vein, Hickey’s (1973) and Wolfe’s (1993) cordate state is consistent with shape models 16-25 of Text-figure 13. Hickey’s (1973) additional cordate-type basal character states (lobate, sagittate) could easily be represented on a similar shape decom- position diagram. The broad regions of shape variation that character- ize the acute and cordate leaf-base morphologies in Text-figure 13 stand in marked contrast to the rounded- base state (angle formed by tangents to the basal mar- gin, joined at the midrib base are < 180°, but > 90°) that, in this analysis, is restricted to models 11-15. [Note: the “squared off’ nature of model 15 is such that it could possibly be allied with Hickey’s (1973) truncate basal state.] This distinction may be more ap- parent than real, however. Certainly Hickey’s (1973) leaf-character classification would recognize a greater number of states in this model set than Wolfe’s (1993). Of perhaps more importance from a systematic point of view though, is the observation that the difference between the acute (model sets 1—5 and 6-7, Text-fig. 13) and the rounded states (model set 11—15) appears qualitatively greater than the difference between the two cordate states (model sets 16—20 and 21—25), de- spite the fact that, in terms of measured shape differ- ence, the intervals these model sets represent are equivalent. Based on these interpretations the modeled shape subspace can be subdivided geometrically in such as way as to render the boundaries of Wolfe’s (1993) character-state definitions much less ambiguous (Text-fig. 14). LEAF APICES Like Wolfe’s leaf-base exemplars, his leaf-apex ex- emplars (Text-fig. 4) represent a family of alternative shapes. In the subspace of the first three eigenshape vectors (representing 98.47% of total shape variance), these define a twisted, trapezoidal plane formed by four outlying shapes (Text-fig. 15). These outliers rep- resent the most attenuate and rounded morphologies. Interpretation of this shape space also mirrors that of the leaf-base analysis. The first eigenshape vector ex- presses differences in the relative width of the apex region, the second expresses the contrast between ex- pansion and contraction of the leaf tip, and the third represents differences in the smoothness of the apex margin. As before, the inclined plane delimited by the shape outliers can serve to define a surface on which to re- construct a series of shape-deformation models useful for understanding the nature of shape transitions with- in this character (Text-fig. 16). After correcting for dif- ferent orientations, the range of leaf-apex shape mod- els is seen to be virtually identical to those of the leaf- base shape subspace (compare Text-figures 13 and 16). In both cases the upper model range is occupied by forms with either straight or concave sides converging to a tip. These forms are consistent with the acute con- 230 BULLETIN 369 qqqd~ 4 V Lf ww > Text-figure 13.—Shape models for a regular grid of positions within the leaf-base shape character intermediacy plane. These models were obtained by scaling the first three eigenshape vectors resulting from the analysis of the exemplar shape functions by the coordinate positions of locations within the intermediacy plane (Text-fig. 12) and then summing the scaled vectors together in the manner shown in Text-figure 2B. Coordinate positions for each model as follows. (1) 1.132, 0.426, 0.040; (2) 1.123, 0.406, 0.044; (3) 1.114, 0.386, 0.048; (4) 1.105, 0.366, 0.052; (5) 1.096, 0.346, 0.056; (6) 1.019, 0.101, 0.083; (7) 1.030, 0.117, 0.051; (8) 1.041, 0.132, 0.018; (9) 1.052, 0.148, —0.015; (10) 1.063, 0.164, —0.048; (11) 0.907, —0.224, 0.127; (12) 0.937, —0.173, 0.057; (13) 0.968, —0.122, —0.013; (14) 0.999, —0.070, —0.082; (15) 1.030, 0.019, —0.152; (16) 0.794, —0.549, 0.170; (17) 0.844, —0.462, 0.064; (18) 0.895, —0.375, —0.043; (19) 0.946, —0.288, —0.149; (20) 0.996, 0.202, —0.255; (21) 0.681, —0.874, 0.213; (22) 0.752, —0.752, 0.070; (23) 0.822, —0.629, —0.073; (24) 0.893, —0.507, —0.216; (25) 0.963, 0.384, —0.359. See text for a discussion of the shape models relative to the definitions of the exemplar states. Shape model series such as these can be used to explore the geometric spaces within which these forms exist and better define the limits of character-state variation. dition, though for this character Wolfe (1993) distin- guished between the attenuate or “drip tip’? (concave sides) and acute sensu stricto (straight sided) condi- tions. Similarly, the lower part of the model range is occupied by broadly rounded forms that exhibit a smooth boundary (models 11-12 of Text-fig. 16), a single, medially located indentation (models 16, 17, 21, and 22) or multiple and dispersed indentations (models 14, 15, 18-20, and 23—25). The primary dif- ference between the two model sets stems from Wolfe’s (1993) inclusion of a rounded exemplar with 1 crenulated margin. Hickey’s (1973) qualitative classification also re- flects this overall similarity between the geometries of character states assigned to based and apical complex- es. Curiously though, in both Hickey’s (1973) and Wolfe’s (1993) classifications, identical shapes are giv- en different names when they appear in the basal and apical regions (e.g., attenuate, apical vs. decurrent, basal). No doubt this counterintuitive nomenclature has a historical origin along with an obvious practical utility. Nonetheless, it can be a source of confusion that is simply not present in the shape-modeling ap- proach to morphological analysis. Mappings of the leaf-apex character-state boundaries are shown in Text- figure 17. MARGINAL TOOTH SHAPE The most complex system of shape models in the Wolfe (1993) dataset is represented by the marginal LEAF SHAPE MODELS: MACLEOD 231 1.0 ] 0.5 | nN Acute f Acute vo a = 4 1 A 0.04 j | 5 Round —> 4 —— Round oD | agp [ | -0.5 4 . 4 Cordate Cordate / 1.0 pq 0.2 0.6 10 14 1.8 -1.0 -0.5 0.0 OS 1.0 Eigenshape | Eigenshape 3 Text-figure 14.—Subregions of the leaf-base shape intermediacy space that correspond to the character states described by Wolfe (1993). Once these regions have been defined and extended into higher dimensions so that they represent hypervolumes rather than planar regions, they can be used to understand the geometry of shape character-state variation. tooth shape exemplars (Text-fig 18). Wolfe’s four ex- emplar shapes can be scattered in an empirical shape subspace formed by the first three eigenshape vectors (representing 98.44% of the total shape variance). The first marginal tooth eigenshape vector embodies the contrast between appressed (apical flank concave, bas- al flank convex) and rounded (apical and basal flanks convex) forms that comes about via rotation of the tooth tips forward and down. The second vector pre- sents a contrast between a different aspect to tooth appression, in this instance via lateral translation of the angular sinuses upward. The third vector encodes the contrast between simple and compound marginal teeth. Within this space, Wolfe’s four shape exemplars define a triangular plane that exhibits a distinct bend in the region of the mean shape. This complex, bent plane presents a convenient surface on which to base this character’s shape-model analysis. Inspection of the marginal tooth shape models ex- isting on this character’s exemplar plane (Text-fig. 19) shows the tooth-shape “‘character” to actually repre- sent a character complex, with several different and overlapping marginal tooth-shape character states re- vealing themselves. Both eigenshape analysis and the eigenshape-based model series represent all of these morphological complexities in a logically formulated, linear deformational system. For example, models |— 9 of Text-figure 19 conform to Wolfe’s (1993) *‘round- ed” state (apical and basal flanks convex). This mor- phology corresponds to Hickey’s (1973) convex-con- vex serration type. Models 10-15 conform to Wolfe’s (1993) “appressed” state (apical flank concave, basal flank convex) and to Hickey’s (1973) concave-convex serration type. A different character-state distribution is present for the tooth tips which, in Wolfe’s model space, may be acute (apical and basal flanks form a A. B 0.6— — T ] 0.44 4 | sl 0.24 a hh 4 rvs 2 A A i] S 004 A a A S g | aH -0.24 r_\ 4 ry 0.4 ea ~ ~ AN _\ 0.6 T Sea oma T T T iene 0.5 0.7 09 1 13 15 -0.6 -04 -02 00 02 O04 06 Eigenshape | Bigenshape 3 Text-figure 15.—Ordination of the three leaf-apex shape exem- plars in the space of the three eigenshape vectors; \, = 89.34%, \, = 6.36%: \, = 2.74%). In order to visualize the ordination in three- dimensional space imagine that, relative to plot A, plot B is rotated 90°. Note that this ordination delimits a roughly quadrilateral space within a plane that is inclined at an angle to the three eigenshape vectors. This space contains the coordinate positions for all shapes that can be considered intermediate to the exemplar shapes. Regions of shape variation whose boundaries represent the boundaries of shape variation characteristic of each character state will be found within this quadrate space. sharp point) or blunt (no definition provided in either Hickey, 1973, or Wolfe, 1993). The former condition is represented by models 1—2, 7-8, 10-11, 13, and 15 of Text-figure 19, while the latter corresponds to mod- els 3-5, 8-9, 12, and 14. Finally, models 1-4, 6-8, 10-12, and 13 exhibit pronounced compound mor- phologies (teeth exhibit smaller, subsidiary teeth, typ- ically on their basal flanks; no corresponding character state given in Hickey 1973), whereas models 4—5, 9, 12, 14, and 15 exhibit plain margins throughout. Text- figure 20 maps the positions of the overlapping char- acter-state fields present in this character’s model set. DISCUSSION The dicotyledonous leaf model sets presented above are not intended to represent the last word (or graph) in systematic morphometrics for dicotyledonous plants. Obviously, Wolfe’s leaf-character exemplar sets are far too restricted to be used as a basis for quanti- tative descriptions of generalized leaf physiography. This is not a criticism of Wolfe’s work because he did not set out to create a generalized classification system for the description of leaf morphology. As his 1995 study shows, the physiographical characters he em- ployed were sufficient to make detailed and consistent inferences about the climates of Tertiary localities. Nevertheless, the foregoing exercise in quantitative leaf-shape modeling has value in what it reveals about: (1) the subtle complexities of this simple, two-dimen- sional, shape system, (2) the needs of taxonomists, (3) the capabilities of modern imaging technology and nu- merical data analytic approaches to address those NM ws) bo ———— = = . BULLETIN 369 A A A A | A AA PN & A rN rN rN DPR DD yu | ext-figure 16.—Shape models for a regular grid of positions within the leat-apex shape character intermediacy plane. These models were obtained by scaling the first three eigenshape vectors resulting from the analysis of the exemplar shape functions by the coordinate positions of locations within the intermediacy plane (Text-fig. 15) and then summing the scaled vectors together in the manner shown in Text-figure 2B. Coordinate positions for each model as follows. (1) 1.263, 0.228, 0.196; (2) 1.215, 0.229, 0.132; (3) 1.167, 0.230, 0.068; (4) 1.118, 0.230, 0.004; (5) 1.070, 0.231, —0.060; (6) 1.161, 0.034, 0.075; (7) 1.123, 0.042, 0.017; (8) 1.085, 0.051, —0.040; (9) 1.047, 0.059, —0.098; (10) 1.009, 0.067, —0.155; (11) 1.060, —0.160, 0.146; (12) ; 1.032, —0.144 0.948, —0.098, —0.251: (16) 0.958, —0.353, 0.216; (17) 0.940, —0.330, 0.076; (18) 0.922, —0.307, —0.065; (19) 0.905, —0.285, 0.047 (13) 1004, —0:129, —0:053; (14) 0:976; —0:113, —O0:152:4C5) 0.205; (20) 0.887, —0.262, —0.346; (21) 0.856, —0.547, 0.287; (22) 0.849, —0.517, 0.105; (23) 0.841, —0.487, —0.077; (24) 0.834, —0.456, —0.259; (25) 0.826, —0.426, —0.441. See text for a discussion of the shape models relative to the definitions of the exemplar states. Shape model series such as these can be used to explore the geometric spaces within which these forms exist and better define the limits of morphological character-state variation needs directly, and (4) the role of geometric morpho- metrics in systematics. Owing primarily to the relative lack of attention paid to leaves as character complexes (Hickey, 1973) and botanical descriptive traditions (see Linnaeus, 1751; Lindley, 1835; Bentham, 1861; Gray, 1879; Lee, 1948), the systematics of leaf shape in dicotyledonous plants—like the comparative morphology of most groups—has developed in an ad hoc manner, heavily dependent on the availability of adequate exemplars. his approach is both justifiable and efficient when exploring the morphological ferra incognita of a rel- atively unstudied clade. Unnecessary problems arise when different terms are applied to the same morpho- logical feature and when the same term is applied to different morphologies, of course, but these are largely matters of communication. As the morphology and taxonomy of a group becomes better known, however, the opportunity arises to achieve a true systematization of morphological concepts that have been observed in the group. Stearn (1956, 1992) and Hickey (1973) attempted to devise such a system for dicotyledonous leaves as a whole. Wolfe (1993, 1995) applied the same concept to those aspects of leaf morphology that he identified as being correlated with different climatic regimes. But, because these studies were based on the qualita- tive analysis of leaf exemplars, the systematic leaf- LEAF SHAPE MODELS: MACLEOD 233 0.6 we } 0.4- Attenuate Attenuale | Ss 0.24 I= Acute = Acute —_/ | A005! L a 3) Rounded Rounded 29 2 aa | | Emarginate | 0.45 x Np aes | Emarginate | i | \ -0.6 $7 =| SSS SS Se | 0.5 0.7 0.9 1.1 13 15 -06 -04 -0.2 0.0 0.2 04 0.6 Eigenshape | Eigenshape 3 Text-figure 17.—Subregions of the leaf-apex shape intermediacy space that correspond to the character states described by Wolfe (1993). Once these regions have been defined and extended into higher dimensions so that the represent hypervolumes rather than planar regions, they can be used to understand the geometry of shape character-state variation. character classifications advocated by these (and other) authors remained illusive. All possible shape alterna- tives were not systematically considered, much less illustrated. Indeed, by relying on traditional definitions of leaf characters and concepts as to what constitutes a nameable morphological feature—all three classifi- cations became hostages to ambiguity in several sens- es. This ambiguity manifests itself in: (1) different types of morphological relationships being used to rec- ognize alternative states of the same character (e.g., Wolfe’s “lobateness” character discussed above), (2) different descriptive terms and definitions being ap- plied to the same morphological feature (e.g., see Hickey’s, 1973 “‘lobate margin” and “crenulate mar- 0.4 5 00— y 0,2 - mt ae | T 07 0.8 09 1.0 1.1 1.2 -0.4 -0.2 0.0 0.2 04 Eigenshape 1 Eigenshape 3 enshape zig Text-figure 18.—Ordination of the three marginal tooth-shape ex- emplars in the space of the three eigenshape vectors; A, = 88.93%. dK, = 5.96%: dX, = 3.55%). In order to visualize the ordination in three-dimensional space imagine that, relative to plot A, plot B is rotated 90°. Note that this ordination delimits a bent triangular space both limbs of which are inclined to the three eigenshape axes. This space contains the coordinate positions for all shapes that can be considered intermediate to the exemplar shapes. Regions of shape variation whose boundaries represent the boundaries of shape vari- ation characteristic of each character state will be found within this bent triangular space. Text-figure 19.—Shape models for a regular grid of positions within the leaf marginal tooth-shape character intermediacy plane. These models were obtained by scaling the first three eigenshape vectors resulting from the analysis of the exemplar shape functions by the coordinate positions of locations within the intermediacy plane (Text-fig. 18) and then summing the scaled vectors together in the manner shown in Text-figure 2B. Coordinate positions for each model as follows. (1) 0.913, 0.176, —0.286; (2) 0.888, 0.199, —0.156; (3) 0.863, 0.223, —0.027; (4) 0.837, 0.246, 0.103; (5) 0.812, 0.269, 0.233; (6) 0.946, 0.082, —0.230; (7) 0.929, 0.097, —0.090; (8) 0.912, 0.113, 0.049; (9) 0.896, 0.128, 0.188; (10) 0.979, —0.013, —0.174; (11) 0.979, —0.013, —0.015; (12) 0.979, —0.013, 0.143; (13) 0.998, —0.187, —0.070; (14) 0.998, —0.187, 0.088; (15) 1.017, —0.360, 0.033. See text for a discussion of the shape models relative to the definitions of the exemplar states. Shape model series such as these can be used to explore the geometric spaces within which these forms exist and better define the limits of morphological character- state variation. gin” character states), and (3) quantitative ranges of non-shape-specific parameters (e.g., aspect ratios) be- ing used to establish an apparently discrete, discontin- uous morphological classification for aspects of shape that were known to vary continuously and broadly within, as well as between, species (e.g., see Hickey’s, 1973 leaf-form characters that were modified from Stearn’s, 1956 original form classification). The shape modeling approach described and illus- trated herein represents an alternative to the more id- iosyncratic and qualitative approaches employed in these previous attempts to describe, illustrate, and sys- tematize dicotyledonous leaf-shape observations. Even 234 BULLETIN 369 4. , 1 Acute Blunt 0.2 / fon | Q . | /-Rounded 3 ‘ <= A 0.05 = ) Appressed on ea} 0.2 rn Compound ~~ Plain 0.4 = ~ d - - 0.7 Os 0.9 1.0 11 1.2 -0.4 -0.2 0.0 0.2 04 Eigenshape | Eigenshape 3 Text-figure 20.—Subregions of the leaf marginal tooth-shape in- termediacy space corresponding to the character states described by Wolfe (1993). Once these regions have been defined and extended into higher dimensions so that the represent hypervolumes rather than planar regions, they can be used to understand the geometry of shape character-state variation. more importantly, this approach preserves and extends the levels of complexity, accuracy, and flexibility re- quired for taxonomic and ecological investigations. Specifically, the shape-modeling tools of geometric morphometrics make it an easy matter to (1) locate the shapes of interest within the hypermanitold of all pos- sible shapes (see Kendall, 1984; Goodall, 1991; Book- stein, 1991), (2) ensure that corresponding regions are consistently matched across all shapes, both actual and theoretical (see Bookstein, 1991; MacLeod, 1999), (3) accurately represent ordinations of shapes within the sample based on consistent linear measures of simi- larity, (4) use these ordinations to define points, tra- jectories, planes and volumes within this shape space that are of interest to taxonomists, and (5) construct linear shape-deformation models at points, along tra- jectories, and within planes or volumes to represent any aspect of shape state or variational mode. Once such models are constructed they can be displayed as additional exemplars, compared qualitatively to real leaves, or compared to prior textual definitions of char- acters and character states. Because these shape mod- els are referenced to sets of quantitatively defined shape vectors, each is unique and uniquely specifiable (thus avoiding the problems of inadvertent ambiguity in definition or usage), each exists over a complete and continuously variable range of possibilities (thus avoiding problems involving the arbitrary subdivision of shape change continua), and each can be used— along with ordination analyses—to understand the characteristics of shape variation in the group and ex- periment with the full range of species or structure- specific shape-related phenomena (e.g., morphological integration sensu Olson and Miller, 1958; develop- mental constraints sensu Smith et al., 1985; ecophen- otypy sensu Wolfe, 1995). In addition, the fact that the methods used to analyze the shape and construct the shape models are fully generalized means that complex organic bodies can be subdivided into their traditional taxonomic characters and analyzed in isolation from other such parts (see MacLeod, 2002b, for additional examples). This means that the standard procedures of qualitative tax- onomic good practice can be wholly transferred into the morphometric realm by altering the level of the analysis such that complex morphologies are disas- sembled, analyzed, and then those results compared to results obtained by corresponding analyses of either partially-reconstructed or intact complexes. Moreover, the roles of variation in specific morphological com- ponents relative to those exhibited by the entire mor- phological complex can be explored and used to refine both intrinsic (e.g., developmental) or extrinsic (e.g., ecophenotypic) control. Feeding back the more formal into the biological side of morphological analysis, the ability to obtain accurate models of morphological structures quickly, easily, and with great flexibility has substantial impli- cations for the entire field of systematics in general, and paleontological systematics in particular, owing to the latter's dependence on morphological data. As shown above, sets of shape models can be used to examine the appropriateness of character-state defini- tions by showing whether they provide adequate cov- erage for the theoretical or the realized range of shape- based morphological variation within specific organ- ismal groups. If gaps in this coverage are evident, shape models can aid in the development of new def- initions—or the modification of old—to address the problem. Even more importantly, though, shape models can be used to explore the boundaries that divide the re- alized morphological space within which organic forms exist and through which operational taxonomic groups are identified. In this sense, the shape-modeling approach to morphological analysis can be used to re- connect morphology-based taxonomic analysis with its main purpose, which is not the search for new and better exemplars of morphological characters or groups, but rather the continuing exploration of the discontinuities of morphological variation between species that serve to distinguish one from another. It is the origin, maintenance, and patterns of covariation responsible for such discontinuities, seen against the background of the theoretically continuous pattern of morphological variation, that give systematic data meaning. In the absence of an ability to access this continuous groundmass of possible morphologies— which can only be gained via modeling—the system- atic assessment of discontinuities in patterns of mor- LEAF SHAPE MODELS: MACLEOD 235 phological variation becomes much more difficult than it otherwise need be. Finally, a word about technology. Even though the mathematical methods necessary for the construction of generalized geometrical shape models from eigen- vector data have been available for several decades now, part of the reason why these methods have not been better integrated into contemporary systematic practice is technological. The easy, quick, efficient, and flexible quantitative analysis of morphological variation in systematics presupposes ready access to computers powerful enough to collect, process, and manage high-resolution digital images, in addition to the software necessary to access, segment, and extract spatial data from these images. Fortunately, recent de- velopments in the consumer photography and com- puter markets have brought sophisticated digital im- aging and image processing-measurement within the budgets of virtually all serious systematists. Currently available digital cameras with circa three-million-pixel resolutions produce images of morphological struc- tures at a level of detail well above that needed for routine shape analysis. For example, the data used in this study were collected from images whose basal res- olutions were 262,144 pixels. Even these relatively low-resolution images (by photographic standards) contained more data points than were needed to con- strain the outline segments of all the analyzed char- acters. More limiting is the range and user-friendliness of the software used by morphometricians to segment these images and extract quantitative information from outlines and landmarks. Whereas up until the last few years it could be argued that such technological thresh- olds prevented most systematists from taking advan- tage of morphometric methods in general, and shape modeling methods in particular, those issues have now been addressed. Commercial products have long been available to fulfill this need. In the last few years, how- ever, a number of public-domain software packages have appeared—some programmed by systematists for systematists—that fulfill the basic needs of morpho- metric data collection as well as the available com- mercial software. In this context, Wayne Rasband’s NIH Image Package for Apple Macintosh™ computers (http://rsb.info.nih.gov/nih-image/, the equivalent Sci- on Image package for Window’s PCs_ (http:// Www.scioncorp.com/), and Jim Rohlf’s collection of morphometrics software (http://life.bio.sunysb.edu/ morph/) deserve special mention. These applications are all available via free download from publicly ac- cessible web sites. When combined with a digital cam- era and the eigenshape data analysis-modeling routines used herein (the latter also freely available via public website, see Acknowledgments), these systems effec- tively remove the technological impediment from those interested in pursuing shape-model analyses. SUMMARY In order to realize its potential as an indispensable source of information about the natural environment— past, present, and possibly future—systematics must improve its Capacity to summarize patterns in morpho- logical data and relate those patterns to a wide range of other variables. At present, morphological analyses are largely undertaken in the same way they have been undertaken for centuries, via visual inspection by trained taxonomists whose conclusions are influenced by the number and quality of morphological exemplars (or representations thereof) they have seen during the course of their careers. The problems arising from this approach are manifested in the breathtakingly low ob- served reproducibilities of systematic studies (e.g., Za- chariasse et al., 1978; Lipps, 1997; MacLeod, 1998). While efforts are continually undertaken to better de- fine and systematize the state of morphological knowl- edge for virtually all organismal groups, these efforts are hampered by the enormous scope of the task which grows larger with each passing year (see Kaesler, 1993): Recent developments in the field of morphometrics may provide aspects of a solution to this problem. With the adoption of a more geometrically focused paradigm, refinement in practitioners’ appreciation of appropriate analytic targets, and the development of new analytic and graphical tools, morphometrics has reached the level of sophistication necessary to make positive contributions to routine morphological anal- ysis in systematics. In particular, the ability of geo- metric morphometrics to express its results in terms of shape models that can be interpreted in a manner nat- ural to qualitatively trained systematists suggests that these devices can be of use in providing the range of shape exemplars needed by systematists to improve their diagnoses. Exemplar datasets assembled with the aid of these shape models can help refocus the system- atics Community on a structured exploration of the morphological discontinuities that can be used to un- ambiguously define taxa instead of the endless search for more or better morphological exemplars that mere- ly represent them. In order to make a preliminary evaluation of the potential of shape models to improve morphological analyses, a morphometric investigation of five dicot- yledonous leaf characters used by Wolfe (1993, 1995) to infer Tertiary climatic parameters was undertaken. In each case, the range of exemplars used by Wolfe (1993) to illustrate his character states was analyzed 236 BULLETIN 369 using the extended eigenshape method. The shape spaces thus created were used to define shape-inter- mediacy surfaces that quantitatively represented the limits of exemplar-based shape variation for major as- pects of the character’s variational modes. Shape mod- eling procedures (described herein) were then used to explore these shape intermediacy subspaces within each character. The goals of these explorations were to identify and illustrate the boundaries between char- acter states. Once the character-state system had been geometrically defined, the morphometric representa- tion of each shape system was then compared to equiv- alent graphic and definitional representations taken from the paleobotanical literature. In each case the morphometric models represented the character con- cepts accurately and provided a range of alternative morphologies that was a least as great stances greater—than was immediately obvious using in some in- the textual character-state definitions and exemplar il- lustrations drawn from real leaves alone. In those cases where apparent discrepancies between the morpho- metric results went beyond the descriptive-exemplar formulations, improvements were indicated in both the formulation of definitions and the recognition of ad- ditional character states. As a consequence of these results, and owing to the widespread availability of hardware-software systems that can be obtained at very moderate cost, the follow- ing recommends are made: (1) additional explorations of the potential of geometric morphometrics to con- tribute to systematic analyses in all contexts be under- taken; (2) students receive increased exposure to and training in morphometric methods of data analysis and representation; (3) efforts continue to improve the quality and user-friendliness of the morphometrics software, especially the provision of web-based data analysis tools; (4) attempts be made to rehabilitate the image of morphometric analyses in the systematics community and better integrate morphometrics into the corpus of systematic theory (see Macleod, 2001a, 2002a,b; MacLeod and Forey, 2002, for examples). 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INDEX INDEX abandoned (@oumuac quarry 35... 050650. 8s0nnes = 174-175 Aulacognathus acceleration (heterochrony)in. sense)cisiene nites -ehoeccciene 209, 216 BULIATUS Aree eRe xe eI Paes ee eh 95, 99-101 AS GEMIOWMNAMASGNES oso opens on owogua ss ate ano coe 9 KUCH ia Sever ee ute severe ey Sua eeEWe, BEy ad Fee tb iae. on 95. 99-101 VAI GOGUSRC OMIDS Us Reon s ox ficat2hay cucoe 2 ois oS ve SDE ne Stee sc eee re 4] PATISTUAl Lamers Mteee reper ge tartye Ray chic, eae en een aycr os Ee See 8,9 PARIVOSMIAMIMNS LARC) 5 ysis ays sts iay yetav cc eueteps enevens | wicee 2A 2130215, akubra hat 2.2... 226s ee ee ee eee eee ese 9 Bactenamtossilized meme en rnan sod Ore ee wee enrnr ae 26 GRIDICE OIS Ws aif suse. ci cits s Hisicys io, suces Neat gp Pe Senay a cus ela ayes aie 174 Bactrognathus Aleqatsiaq Fjord Formation, North Greenland ............ 28 CLIStOLTLS Reta a are ee ee es een nea 189 fILAD . oon no ebbeonsurwoenea ddvolegcae burs gogo: 183 EXCa VALS a Mer eter Te MENT 7 cnr te She Tee Tee 189 alloc hthoOnousHbed Sierras ea sneusit teste wench inte siemens tate rele 133 Harniatiiseeee tyres sitemeter abt ae ee ee, ee 189 PAPO LOC SLITLELTOLUS as aoharac- ys a ieee ae cue svete re so eae nee 68 lanciaeess area re re her: meee eee in he eee ee ened 189 Amco Member, Pine Point Formation ................. 133 TOLLTLULOS ey een eee ene ye ey ee re enone SAMUS 2. 189 NINE) y grins GI a Bib gato eae plots SU On bo Bie has orn oe 7,8 balognathidign srswnarcucesncisunes SOR une ogge toe a creutue aces wRereRS cre 69 NINOS IRCISS (GSUSP £ Dede ostenpeounesessbonou men 7 Baltoniodus AMON PROLNAIOldes LONE eeayetererete avers a eee tele| siete ore 96 PCLOAC Berra eae hen eter ok oment is Mena een AA RAL eee ee 38 AVON PHO BILALAUS EVAL TETISIS 2 <0. ahere) «el irae a) ae el stan 38 VEIADILIS ms mana aye Eheim eee Gen Te ere Ce 38 anagenesis(anagenetic) 24.02.62. e4ee eee 207, 209, 215 Ban eladeshigeaegepncveuss cette ca Sateh os ne ach mere eucme onc eee 9 AMATO MD Ge fey at = to is) Abeucs, ahve siqutaaivs-rosliah elgeis) sMaitsiainevehevisiae eee sieeie clseis 220 Bashkiniangs tape: ah ckcwousno cepa cveraie cel ces ave jreearspencieee see oe 213 ANICEMEGTOUP a: ose) aes soe eae Be es eer) DOsO0=02% 04 BatondRou ce tes mya pepccrensathes ntact rene Rhee Ieee 7 Ancient Wall platform .................... 123-125, 129 Beaverhill Lake Group ................ 123, 132, 151, 153 Ancyrodella BoC ein aus ark trade Bk SON ioc ee eid A ek ek 200 CHMAULCE Sos OD CEE OA BAO Ait 8 5 GCC oe 163, 170 Sfullil Sone PeoRmE eo OOM Gon GG o HOG Goh wnt 10 GIGI Oem Gey werent ga, PR ee ON et gy eae 163, 170 Belodella PINOGD Sans tne nee. ea ee ee eet 159 ONT ACTA ion Meyendia iit eae a eee oh eS 108-109, 112, 115 IDOStDINOAOSAy aver tne = ty eee haere asec cael ere 161, 163 GOTELISBELAS fav's 0 Behn) got ho ta Roca 108-109, 112-113, 115 Trait hn TO ane SIRE 7h. tt ee ee 161. 170 PAUP i pevavatcne: “foun! Feo Napien aye! ate Diane eens de en URS Suche RG iKilis} La tirediloh Gi bead asaya ey cyte acme 159, 170 EOE MESUMA) -orleoa 2 Nie inne os 6 OE 8 os 109, 112-113, 115 SONG Ag I = ory hele o ee 159, 161, 170 Belodina ; ELOU SULLA hiro ae vtec dee Fe Lae eae al Mote einen sh ee peNs \ah dee 170 ee By pepe A. ae! a a gece 38, 65, 68, merece iics hare n ee ene 117 TLOMILOT EMS LS 26, ~ Jose cua Aa ees Gnd) lesa ee seca pot isre as cs CUR eee 38 Nagi ek os ee ee 179 Besselodus Rp rset Acris erage tyekers heuer .«, Steen, ecmehet MCR 28-30 sien Dae a Oh RETA GH RY | otter ONO AeA COCIER EC He OleOle. eA ONC 28 Cieulatds BICONE! ee reg ae akgee hCe gapta Leta ES BharativWikhen| Ce eeverne ste ah easy c= clr ete aes cee Se aS) GEllONtZONSW 22 aya sosnk Sis ate esis ee See eat os te Dx cor au avenge ahem eae 96 Central AlbertaiBasiny 2 siasie © Ge ee se eens wre, Weiekehon: 153-155 Central Alberta:subsustace 2h ect atoms ce es ie oe ee 124 Cenitvall INGVaAd ar Kare ops eyoascenh ens ey be ee eben. seuss ep eoenens 131 GeVENNES 2 ods Tame est Seo aldose 4s pcculsy ace yeyays: as veg sieswanepeysheus 174 Characterestatesign 2. «.cacisrs eke @ siete, oney eevee sie, sue ustens 221 Charactems)’ sa). cuca gsreususie sed eas utes teteemay shec sca} aes. sys, Styrene 219 @hautanquals Westy ce wget tho et acne ta cisiomchcn mone ss usr enon 187, 190 Chaz yan epee ie xcasc keto ashehe ts woken aevey ater cee tats esp-enate vas 64-67 Chaz yankS tage Mer cle ake igure sins wisuneel eye toqcue Oi sieme 46 GHiCa oe Oar eae Nee eeuchoan eee sh nen eee oe sre ner: 8-10 “Chicago School” of paleontology a Fic. 5s ae 1 ee eee 9 Glnimae $88 see anc eastern ey casey cng aha yattael sartaataens 211 213, 206 Gino SnAthuSaepseend sone eee re ae aay aL Ta Sa oie 67, 78-79 CHOMAtA res erres sateen ee an seceemere orca noche s Lea e ee 200, 205 CGhondirite ses ten gone te, sce hehe asi spaliewsr a area ae hia Ges easy a ae 60 Chosonoding rigbyt “4s ee sc.c0 8 So Peo Ses ls hs aed Seana 38 Chouteany Limestone. .60 susespsnsvs: oes aye ee ss Syeeeud ava somes 185 Cincinnatiam: SenieS = s..4,4. Sin sos sieve, eek Gos cee eee DSO CANCMMH ALAM sence: fees. EA ware Me ce a eet. aha ehiebemaep ee oe Mears 28 GlassicallmusSic’sgas wicca cide recA ne lM oe Citas Gen SIEM a ons 7 GOES. mea rcncnerctess cue een aieme etic eure bastante sek eared tar: 9 Golapoconus.quadraplicatus. were. evs ge = os hr 38 GOLEOAUS See 2 ak Ra eee sensi hay eis a hdSia cane are tere eee 65, 84-86 collateralhévoluviom. 754. As saul w om aat. clear Moe 215213 COMUHUMISS CATINUSE LONE | Ure, Seeks ore ye rereuenn ie, dues Sete saeeetens 185 condensed sedimentation (Ancell Group) ..........- 62-64, 67 BONGO Pa ee sok ete ee Ie ae eee Pou asl RES re 8 CONOGONIS) nesccie soya Sige sca im, wosag ew Be aay 75292 1/32 183 LAUMAN a Sev « Gia cease ir ieuar cities espe. Gi, eras ene a) sys,er a alee TASS Strath TAP mee cm ces: actus ase eee eae ene hats tee oe Nas} ZON al uUratl OM sy asics eee) eee Sema cde yas cy 173, 178-179 FOTW LMON 2 is cic ea nle era. 5, snap IGN Soe neds) ere oS era eee 176 ZOMES. soaks eYRee Seaevg, SA aN Sah eva eee Od ocuiEde ema ne eee Penertae 173 CONOdONOLOSY™ oo Sises . Saco Ge tealane ty a) sus sei oes ee Skee 7-9 CONS UtaNeY 25 RE Rene. ee eae et hea eerie een Ome see gig eee 8 CONVELSENCEY. Amita sis a gosos Boe neta auavtec ouepe yc ayeee uel aie 213 Gook Islands? 2.5. 5.2,5 36 oa sels woe a8 Oo Gee eeniene 9-10 Cooking Makerequivalent 24 2.28. cc 2 ee.s cee te eee 124 Cooking; Lake*hormation’ ..8s y-c sone ea eres 1511535155 ‘Copenhasenvrormation: 26 ..ccu « - Gute eke erent 37, 42, 46 CoralvillevRormation: : .iie0.e eels ces ce a steve pane eee 1305135; Cordylodus tae 73 ig. won satis aon akar siti e eines Caco onl em ome 19-31 GUS UIATAS-S pocketed ear ote tied Mea aet e hee ee 235.25 CASEVD. «5.5 Sd eo Pade DA CU Ee ane Dar eee 23) ULeTINEALUS “Paid eek Re ee 23325 lindstromi Wb yaa ee his = sess seep ee 19, 22-27, 29, 31 DPULONE 5. si5 a toe hE. he wean, SOD IS ale te Sete Sees Bel ROS 23 PT OQVUS) (50304, di sys ie. eaaeled Avie tb. Bi gps hana, a, a0 digs, = Slane ees 23525) “Cordylodus” OTTIQUS? fo. 3 & ite etek ed Gace 2, HERS AES ashe eten ates os eS 25 TAINOSUS oicoct6. 6 sie veo 6 ns ol teies okie ios 3) ute wilt) Ten ke, GENES ORO ROR 25 comespondencesanaliySisy vs cnee-wereie tates yeni seen ee 221 Cornuoduslonsibasis’ . i053 ae fsa ee os es ss Oe 38 correlation) witht TARGCyV.ClesM insect tense acne eshte nae 157-159 Gostistricklandiatcastelland ae tee 93 @outballssMemBereeiegem: cotetacn sneer tr at ote peed ee 135 Goumiae: Fatresiter: | tae ene ke Cee Se Peete teen 176-177 IOLMALON! Peteedares crake mus rerekcreie tent coe ett ee ee ee meee 174 Quan y.F42 ys Sos Ree eee ge eee ee ee ee ene 175-176, 178 SOCHOMG. ge cic ema ee ee atataue, cehauel sy eecks Ramet ae eeaen areaene 174 COVaTlanCey sie aisys ee. esi Seeuans kets cep ee Re ee 222 GrONGeRaG™ 2 rae cine: sale aat s he tees cee 123, 130-131, 135, 142, 144 LOWENSISK ES. 55 ren s ous wi Bue te Bowls ahah cucu een eee 144 Ch TOWEMSIS— 2 areie Page ecerstn Sen se eae 135, 144 SP: Pafet depts 3. sfatepsr teenie, obese ere, wayne ane genomes 130-131, 142, 144 Grepidar Zone® x cis ok: tose choles cas cee) + coe S.uke paren ee 176-180 Gruziana Ichnofacies: (. J... 3 2m cts e cicwee © ee 123 Crystal) Peale Dolomite: 221. 2s. a sree sere oh) <= 46 (CULO SMALLS en ache alten Renee ono Cee goa eee 68, 79 Cyclicalypattentiy n. 6 cuss e was eates) State niet wie eee 173 GY FLING Piven.) eat taragehs eccte caioee tre Geen Tere 123, 130-131 ERIQUCIT.: Ping ae Says oie eee ne eetous 130-132, 135, 143-144 UMDONGIG n2,ihe oh res Gas aa lee EJ eee ae ee 144 IDV ETO ISLET tetra outer ero raicery a chrea neo tona'a SS 211, 213; 215 DapSilOdus: va sss BeGcc facts a fs ee ed seas eines see ee 69 TAULALES) o's, cits Fi 5 teat Baile ini a: 0, Ste ae Sustmee eceoas bons, ee ea eee 38 SP nice my aeyayis a cate 105, 107, 113 GrasswaG@reekyshaleiar gt recsuens sage oncdcnd «vets airs Che. oecwere epee 7 Greate Basins eae thenceeacaes sie ola syer sus eters one 133; 135 GreateSlaved wake ware. cwaceinn ce tos es Ae pcre Geren soks 132-133 Greenland, Aleqatsiaq Fjord Formation................. 28 GriottesROmmatlOMies sete eis ses = Sis che ue cl st cues eke elses 174 GSSP MP eeyayser rcs eae eee ees, Se cny alias SPACE Ty stee She sis 172 ‘Guilmettesonmati Oniesewesyee-teeeshenpelevetsuc ever eemetr tomers ek 133 GYyTOPhyllUurmunaCKeNnZlerse. 1. .vne = pe oes ley see te eae ves ee sys} HMaiohtt Greeks Mem beige crene ela usyea2 terete) ues fol steer eee 188-189 harderoundsh(StyPeter) ia sea nienene achat epsesesea eels 56, 58, 62-63 Harding Rornmation Colorado) 277... 27. enee-en sta) eae 78, 85, 86 InEideHIDENelol an Sa an oo ah aod hohe ho ooo moos 9 242 BULLETIN 369 Hairy, Sr lruman RESEGVOll eset as wagons et cee edicts tray eemenane 192 late Naz We [oh tale Onedtes et cn eee ais cogs n Otho Ohh 6 aeoks once. 9 Henryhouse-Haragan formations, Oklahoma 108, 112-113, 115 Hlerontksland oa. csckerace etetsrterstre yes csc crac etna wiseciee mae 10 Nheterochronyi aasrwarceciine cones chet rackets eter: ogee een dee 209, 216 highestandysy stem toact ema cesta otal cus a eet eR eee ee cere 129 Hall SS808isectomnGAR ii ceeices cee. one, sue eoeeieeenon crs 36, 37, 41, 46 Ne GR her (AL Te ER er ae alr ich eee rar Deere (Saran Ro sedur Es Giolo 6 sis a 39 GULL TONS) 9 PAN cao ss ESR RRC ee ee 38-39, 41-42 NOLDAENTALA se Naoko she ysuc ie ene at hae eke A OS PRITIALISC TM ALG te ac tr aneneaueke use rhe Shs GasNedns sea erste ee 38-39 SOUTAIQ S| Hopes Suche. wee. 4 euaroeRaLN LER Ren ene tees pea eee 38-39, 41 SEPTOISGL:» co easiness aeudcsMele payets al Raye eee ete eon teks 38-39, 41 I latofArofep tet TIS Ns. CAS Heer oho .coty co Ole ae Care IO cee BIC 22 Fel Reh ZA AN? Wages oy OR co oO CCI aati PCO tor er ee A Mee Oey 25 Ibex Area s,.; Wows. datamcapenane elena as iscdue travers Que sys) mete Oe 36 NDEXTATINS CRIES) Meanie cous, csikede) Snel sispede te atches sues 24-25, 35-37, 46 LCHTOLOSSULSiaasa he rere ys stati neh s, = aptamer Mice ee meets 123 UGTIOCUStatehe ccie etetate te enene ners 107, 109, 113, 123, 130, 176, 179 POLOLETICHESCENS.. Sande Sixtus Ae ere) o WI Geen cage SeRe 2 109 DOSIWOSCHINIGLUaama a. tia) ceitc, sree ats False Ms] ‘oats 109, 112-113, 115 SUDIETIMIMUS, boasts mente ole eon eral vie 123, 130-131, 159, 170 WOSCHIIGU = Aj a anche cathe, Meeeaipaiiah 6a) af aan 109, 112-113, 115 Icriodus postwoschmidti Zone .. 2... 0.6 oes 109, 112, 119-120 TerioduswoOschmidti\Zone) sacs a son sor cts oa oa es 109; 1135. 715 TGiOPriGniOdUsKfurnisShe We oils cae Sale ve es bee ce ee ee ates 187 Mlinois;Survey- Fs dis 3a aus) ceayelis Gisavts ender gy eel wie aye as det a 3s 7 Mlinois; St. (Peter Sandstoné 22 i. sus eee ee 54, 58, 60, 65 Imperial Forestry 16-7 well ......... 151, 1575 159} W615 163 Imperial Judy Creek 4=35) Well! paca wens te RE oe 156-157 Indianay. St, Peter Sandstone’ aia aqmau edocs ss een 53, 65 ASOLO PLCHPALEOMEOLO My weal ave aye a eeectaetaileteyial escape aurea a alae 219 TO Wal hace conshesa- ny crch tee srscva gear «Oke Gh eee wb oun WMS Ts S539 LO Weal City arte rs revene sodiaeuis: Swdiesoie tater ats sadman'e (eye eet Sons fh eae ama Stone 7-9 lowa; St; Peter Sandstone? fem wien. enn ee a ee se eS = Or, AONStONE; OOLMUG Fn iow te andes cue yb va the Gre Geum Oe 60-62, 64 IShkarwaz.bakas tates ctcasicarasctoaers wares rents satis tayt 65-7 tsosticha-Upper ¢renulata Zone G2. nah s vies 6 6 Ge one eels 185 James) Hudnall DistinsurshedWecturer 72% i). sere scheete. @ a 8 ADAM hans co veden enh Vemee rer aua Nenereunpe atest exe eae 212132216 AZZ Ee eae ahve Sis ect ee ea ET USP ene ante oie Lok epem sy omen eee 7 Joachimy Pormatronis jae wees snes a ees epeneeee = 58, 60, 69, 79, 85 Johnson, VE GeiCUess’ )\c on ace. eos see ey eres cae ie: rciepe arene ese fe 10 TONTISONCA rea cre Ga titres. Saehatsl piel Ste eee eee es Stee gees aera 135 JOMS OLMANON ce steaks kw arsine cis cy ooe rene eens tee 39, 44, 46 MAG ALAMEStONE? wi etncad a rte agama ow Seale Olea ene 2 46-47 JUuAnO griathus JAGNUSSOML — 5 vosic ioe « ae a)teen we fa avis etus) se) Sioa tees 38 JUAROLNAIUS VATIQDIS. Giacian & Gow ae ove gels BIE in 38 Vudy7@recksreeh Complex sere te pice ce ewenavis: «i fers ame stews eteels 156-157 VUINUGOTHUSTETUNGAA 1c noise winters @ Ge kieee St ce ee eee 38 SUVA oop Sais. aptang poy ain cele: rz ia ay at cel win sp =) oa easy el ose 205 HUVENTIE:CONOGONS: Gre ete ss cuctsns etersenousdeuetieets 64, 75-76, 78 K/TBOUNdAaEYs sys iecs = ccc’ oars Sie 5 elise see eae) Sheu eiehene trees nee: 10 Rakwavitaketsrycriassnciiatis, arcrviear ey mers sige cere memren 132, 139 Kakwa-Cecelia lakes, British Columbia ............ 131-132 BranoshiShale:€) 62) 4 ypc: fata cca ove sunpoie oso tere hola) Qin Ses eet oe 46 Kansas, ot; Peter Sandston€:i.. s0¢ 661s seta eins ogee 60-62, 65-67 Kashinan Substage se 20. ci cies cu enecne 200, 211,213; 215=216 Kellwassemevent) «cassie costs cieibr ec eases Geet eee cee a 173 KellWaSser mass) CXtinCtiomin =;..: eesreie eos en steady enuies 173, 179-180 Keokuk (Simestone: ean oer e se wen 8 184-185, 188, 191-192 keriothecallwealll 22a 5. sie alge pane ete wg ransee ms airs ae abbige: Sock ah 199 Kimble ‘Gounty, Wexas) 25 = eye cre wees esc steno so ele ieee 203 Kinderhookiants .ics.5-00« sn mck esense eiees chemeneneaems) octets 185 Kinderhookian-Osagean boundary ................+.+-- 183 Klapper, Gilbert ..... 5-7, 20, 22, 53, 56-57, 93, 151, 161, 174, 183, 192, 199-200 Kdappenduni tern satis at ase ueremeyie asters iste aie Mel eat te ahaa 174 Kionk, Event) S nests actus © scexulchne cidiae oom tiation 106, 112-115 Kilonk,@zech\ Republic? 22) cs cuee er e= sonc deers asian LS ehisS KockelellaichaKiabruptus crketene sie eek 96, 98, 100-102 Kockelellaranuliformis d Satie atid ec loedione a epee ERED 135 Schwasennidaei(Schwagerinid) 2.22. n ys nee 199 DS COLOD OCUS HC Xerg a NENT PR ec ete NCEE Tote FRE Penta on Sie- fens 38 scotchiGrove Formation! 2.5. sie eco e a 93-99, 102, 104 SGyPNTIOAUSIPIUNUS| rms tes la) abet Wie vey -\ f.sne taken eee cs. cnles cee = 67 sedaliavhormationy fo... 005 2 a 184-185, 187, 192-194 sedimentologicaliproxy datal seni s eres eerste ee eyes sat 174 Seite lose IMMA oa ino Aegon Hondo ono nant ac i, SCDIALIOMOSDINANCLLAterwat nape at cas ayenateteie = 2UsteNew ss ont fe 185 SEQUCNGC Alpacas eeye cara, ees iat rn, ter shas erent sbsartene on Rie ere 132 SEquencegs tratlerap Myer as carly vel lie a) oe) ef Seeveee =| teste, ae 128 Sequences-Guilmette Formation . 35.2 .35542220080- 133-134 Shapes analy Sis Werrerieweuree Pps ea ay chin). aca ce ct isgsnsy sea eae 7-8 Shaperdisparity es crs yc. 2s ce tccS otis aa aes oes eon eee 220 SHapeUnctOnMey sa werewa cyevsha recession svicy Nisutete ce ensucet at vetoes 223 ShelROUEompanivgerwencatee ews noe rena ierts oleei te cle eae 7 Shingleveimestone: ways sys ae Gta @e os ose cao sean eleneeeweeees 46 ShinglesPassYSeChion saa -ye. tiers, cys sues: =ysnadwet ones eae 36, 44-47 Shingle Pass-Ibex Area Composite section .............. 45 SaUTIAN! Sieg ees see reoeieve eg ce se Paar fe ca bese caer cuciee A aevareee de 8 SIMPSOMGLOUPe iva eeencseae eae sees ce or enehensee: Meret sweat 2 61, 65 singular-value*decompositiony. jen 2. soe ay se ee ce 222 SEPHONOGELIAISOSTIGHAM sre alt eae ey aac sy oateee suv onstere aaa ae 188 Siphonodellapsp var eueneeetetel suc teueeseoeiceeaeae ea ee 185, 187 SKLIELO MAL NU Sten teod teehee aes Seater a RS Tete 130 ISKELELO SNALMUSEMONHUSI coat pee seeene eee aiosaah te emer eral eee 1305 1a SOLU OS Mts Se Aeset a SRR ERA sehen OTE eee OTe 6l Skulltockiany arya seasveyoscacrcuses eee ek evel eaves eras ae 25 Slave PRoint\Formation, %.24)c04 a6 2s sil: 124-125, 131, 133, 135 SuithwickiHormation, LexaSaa