HARVARD UNIVERSITY e Library of the Museum of Comparative Zoology aan I gem). dea thelien ay . age co ey p hae dg Gia is wi Ny Pn com Rip $214. eg 4, PY Sys A Lames Peroni 7 | it ii oe meee eed Ce | Ge a ed a Begun in 1895 VOLUME 113, NUMBER 355 APRIL 20, 1998 Frasnian (Upper Devonian) rugose corals from the Lime Creek and Shell Rock Formations of Iowa by James E. Sorauf Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York, 14850 U.S.A. PALEONTOLOGICAL RESEARCH INSTITUTION Officers PRESIDENT ie. bee yaks oer eee oe eae Eee geese eee CONSTANCE M. SOJA FIRSTS VICE-PRESIDENT a: canister eee oe eee Ba. yates DONALD L. WOLBERG SECOND VICE=PRESIDENT: 2s) 50o6c She oe ORE Oe cera salve ee SHIRLEY K. EGAN SEGRETAR SY) | ois drier deve Ge2k cae Bane le aS Ee Tae EE a HENRY W. THEISEN FRRISASURERY (5/57 car epabetiae Sena Se ale tay oc head ooo Neale CLA ToRa eee HOWARD P. HARTNETT WDIREGTOR: Sri 3% clei oxesovtess ei areas hc iohere oi Sisae sla 8 cua peneolepalere Sesnerene WARREN D. ALLMON at ae Trustees CARLTON E. BRETT (to 6/30/98) MEGAN D. SHAY (to 6/30/99) WILLIAM L. CREPET (to 6/30/00) CONSTANCE M. SoiJA (to 6/30/97) J. THOMAS DuTRO, JR. (to 6/30/99). JOHN C. STEINMETZ (to 6/30/97) SHIRLEY K. EGAN (to 6/30/98) PETER B. STIFEL (to 6/30/00) M. G. HaRASEWYCH (to 6/30/98) HENRY W. THEISEN (to 6/30/98) HowarbD P. HARTNETT. (to’ 6/30/99) ’ MARY KANE TROCHIM (to 6/30/98) Harry G. LEE (to’6/30/00) _ GREGORY P. WAHLMAN (to 6/30/99) Amy R. MCCUNE (to 6/30/00) THOMAS E. WHITELEY (to 6/30/00) SAMUEL T. PEES (to 6/30/98) DONALD L. WOLBERG (to 6/30/99) EDWARD B. PIcoUu (to 6/30/98) Trustees Emeritus Harry A. LEFFINGWELL ROBERT M. LINSLEY JAMES E. SORAUF RAYMOND VAN HOUTTE WILLIAM P. S. VENTRESS BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA AY YAP LEA NRL D Bay ANTE BY (0) fine ees SRL AE ROLE IAI SS Gide dca twoe meta Ho mobs edierce Bb etonie EDITOR Reviewers for this issue Ross A. MCLEAN WILLIAM A. OLIVER, JR. A list of titles in both series, and available numbers and volumes may be had on request. Volumes 1—23 of Bulletins of American Paleontology are available from Periodicals Service Company, 11 Main St., Germantown, New York 12526 USA. Volume 1 of Palaeontographica Americana has been reprinted by Johnson Reprint Corporation, 111 Fifth Ave., New York, NY 10003 USA. Subscriptions to Bulletins of American Paleontology may be started at any time, by volume or year. Current price is US $75.00 per volume. Numbers of Palaeontographica Americana are priced individually, and are invoiced separately on request. for additional information, write or call: Paleontological Research Institution 1259 Trumansburg Road Ithaca, NY 14850 USA (607) 273-6623 FAX (607) 273-6620 © This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). Accs eric ontology APR 27 1998 VOLUME 113, NUMBER 355 APRIL 20, 1998 of UNIVERSITY Frasnian (Upper Devonian) rugose corals from the Lime Creek and Shell Rock Formations of Iowa by James E. Sorauf Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York, 14850 U.S.A. ISSN 0007-5779 ISBN 0-87710-446-8 Library of Congress Catalog Card Number: 97-75707 This publication is supported in part by a Corporate Membership from Exxon Exploration Company Printed in the United States of America Allen Press, Inc. Lawrence, KS 66044 U.S.A. CONTENTS Page PADS trata cmeye neti ies aah cue teany ss Ge, ceo siie evinuis. ovaiteesices = sSmenfe aiiey sicw fa cat/sueliby atreita iiatcervs cur siyy rota ads syib yoleenus uous “elews kougee sateeaiele cogseaisl Sepaneieme tone ei tenes 5 e,c 7 LeRoy GG ocr © Oe boro, Tr 0 Ged OO DESO CRO) ORR OR AER ORIEN CRON ERE, eee cLc ericish a rdcuar Grain chs 0 GIR ioed fas ofa Po. cd ey Grud Ole ond Cie ic Gioerene I 7 FACKNO Wied SENSE esyarai ter ares = nares T ome Remahces hai eyienor e's te Povieucile) seWerolaial hoe ots Aatncen agrees ope Me calteemame netsh Stem halla pomeAv CCW vou at meaner ewer 8 Sintiyaeiaw 2.4 neato wae ni oaths ae op UG lomiOgini Seen a Re ene Cen, Sein nic ol ee own aint mamta Gb en OO. Be 9 SHENPROCKSEOLMACLOMY seis Woke eters ey ch erisi her oh oy. 8 Sie os. cistern enotome enue cenae ehenenOnere) Cue me Moke rtentar ereter telte en RnR MRR Wc rome ie 9 Na asonuGityAMemiDen cyaterc seo ction ce enter yy tte steele tobias Serene ha call yarsetpatiapla: ashe us) dtie-soual Slasa.o GoM esis (eure Monee wehedtene sere neve semen Rename teR wee ae settee, 9 Rocks Grover Member sec ot cictescne batho st stete irate woeekene: chore wiieleeocie ts. ENOIR e eySuA een ores, Chanel ohne emeremere lene occuabolovens mel oheucwevensmemaneie 10 INGA Giles amawon oorado dal Oo dod abr Od ofo Oldo HIG a CIS au OM eno oma o ae honUDomT oo mb Geno boo oo 12 IL Tt (Che RGAE CT Ass Ho ate hoa. Gocco Oo ol D-oieet Cicer DO a Deas is eh eee re Ene a acco gh ceoaicheeic oOlun Oma aa oo 14 CerrorGordos Mem bere iene che enero MT onl aesoriocl cre senveiseucn) E rou | To el Cua peere icine ser auewsveue’ la deen curereda reper Gutreney sie uci mene neeetietee 14 OWENEMIE TI DeTMn ce tey kets tee cidey een yc ox crcel oh ofr Mico Met oe teak ein) spelen Ske neeslropiossetietensllihice esdatautelce ds Meas eae Bey Taek memes eeas tea ee eee ee 17 [SOS TR ATETR SING o codiqe e/Bim oldblo Oso ens Ol OIO SICKO GiOyO1 0 (Oooo! Cioks ECT CeO OTIS Ma CMA ONG ain Aro IIe OOOO Coo.coDa sn iOa noo 6 21 ETA] Omg ithONS) tera sere rh says cece ak ois ay epi vos fay eursiehemig ig oes sige elven exeuces cute sls evs Siastrat-e. oe oa'vaylenls coral fonjaiyetde as. svtayie a sefeicaviahsasitee su-ecanetal steer aheuetoene 23 SVAOTES EEOC coohoon coupe conten reoO sd daosses oe oObonoeh enon Ou soo goaded Rabo Gao ONUOnO OOOO 24 EMPOGUCHONM wera Rer Torah yeh wsro onary sig-asel oa sued suclucy oe Nous onebots hc ay clcoria pe /-yomeiestie: corrsirsirsecsrichrcivacis (avalecctyewel tan Mememea atm sbtct esol iret care rone ne 24 INSROS (TER. 2 5.5.0 Glelata 6 BO ee oD Ce Otte cura Eee actin. Hache a as ee eneea eons Saino rena piece eae Rom old.o10, 5 0 25 S¥SISMEUCS “. oolisouges lagdae edo dddgomoOd ogo o CUoOmO DDO OMO ROO HUMOR MODUS OOO OsoOK nan Node Hoe oe ods 25) EVI hy laebeya) MANGE Ces Sor ee ah aoe OOOO o Gd boob uod Sooo OOM OOo EE CUdOd bombo dons hombabedenawoscac 27 Gemuswowaphyllarin. acters creche. ote MGS eo at eV eR ot ta Ta arte) cee tee Ee Sie tee cate RL AAS, Mets eee Mevrenrewall ou SPA ei ue Cowen temp em 28 UES] OPAVATAE x yale) fa east at Sere ees fo ck w: Gece SPS NS) at cotey oapte wba Seay Sreice sBiresyrbp aula ody ana: Rhee! NIG ceren/atle) Asal ceteniel arora) aoe vewone ants) sieeir = r= a eee ae = = a. _ > = @&— ee — pi 2 _ _ 2 © rh tents» ~ = > = ‘ = —- a 5 Bj ~~ > - a Pa 4 a - a) a" - @ a = v a © a | a = —a ww tome. hn aught) wie = ae cee ee at 7 7 _ -_ ed + a @ 2 on Se 12 Oe = - a = =e =| == = 2 10 " | F Rockford Section $ ; OLD. | VHock{ord #20 W Rockton AYJMY) Wy 4 . u Shell Rock Fm. | Localities between Nora Springs & Rockford, lowa | SE aoraes 9 14 ty) 5 1 Mie | a eee! — —_— =>} — — — ——— —_— — -_—_ — Text-figure 4—The Shell Rock Formation exposures in the region between Nora Springs and Rockford, Iowa. Details of locations and stratigraphic section exposed are to be found in the Appendix. 14 BULLETIN 355 Text-figure 5. Exposures of the uppermost carbonates of the Mason City Member along the Shell Rock River just downstream of the Nora Dam (Locality 8, Appendix) in the background. These outcrops are the best exposures of the very coralliferous beds of the upper Mason City. Photograph taken in June of 1986. To the south of Nora Springs, the Nora Member outcrops in an area west of the Shell Rock River (Text- figs. 14,16), as at the former McEachron Quarry at Portland, Iowa (Locality 13), at the county roads quar- ry (Locality 14), and along the Winnebago River at the west edge of Rockford (Locality 20). Outcrops also include the splendid exposures (Locality 16, Text-fig. 6) at the former Tom Williams Quarry in Section 23, T. 96 N., R. 18 W. (Koch and Strimple, 1973), where a slight downwarp of the strata drops the top of the Mason City Member and brings the outcrop belt of the Nora as far east as Rudd, Iowa (Text-fig. 15). All of these outcrops have yielded abundant fossil rugosans. LIME CREEK FORMATION The Lime Creek Formation of north-central Iowa, with its outcrops in Cerro Gordo and Floyd Counties (Text-figs. 16,17), is well known to the many paleon- tologists who have collected the beautifully preserved and highly abundant faunas of the middle member. These were described by Fenton and Fenton (1924). Specimens of the Lime Creek fauna (or ‘‘Hackberry Stage’’) are to be seen in museums and collections in North America and throughout the world. More re- cently, outcrops have been considerably degraded by overcollecting, and by covering through slumping and vegetation (Text-figs. 18,19). The Lime Creek Formation is subdivided into the basal Juniper Hill Member, medial Cerro Gordo Mem- ber, and upper Owen Member (Text-fig. 19). As the Juniper Hill Member does not contain any corals on the outcrop, it will not be discussed in this paper, ex- cept to note that it formerly was used in the manufac- ture of brick and tile, both at Mason City and at Rock- ford, Iowa. It is a pure clay shale, and bluish where fresh. The thickness shown for the Juniper Hill in Text-figure 20 is only the amount exposed at the Rock- ford Brick and Tile Co. claypit at Rockford, Iowa in 1967 (Text-figs. 21,22). The unit is undoubtedly much thicker, with a maximum of 21 meters estimated by Day (1990, p. 615). The name Lime Creek was proposed by Calvin (1896) for the unit as exposed along the banks of the Winnebago River (formerly named Lime Creek), at what is now Claybanks Conservation Park (Locality 28, Text-Fig. 16). Although the name of Lime Creek was subsequently altered, the type section lies only 1.2 km (¥%, mi) south of Littlke Lime Creek (Mason City S.E. Quadrangle), and use of this name should entail no difficulty. This locality also served as the type of the ‘““Hackberry Stage”’ of Fenton (1919, p.355), as it is within the area then called Hackberry Grove. The type section, as exposed in 1968, is illustrated in Text- figure 23. CERRO GORDO MEMBER The shaley, highly fossiliferous beds of the Cerro Gordo Member of the Lime Creek Formation are ex- posed in a series of natural and artificial cuts through the low hills forming a belt 5—6 km (3—3.5 mi) wide DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 15 Text-figure 6.—Shell Rock Formation on east wall of Tom Williams Quarry, Locality 16 (Appendix), with almost complete section of Mason City Member forming cliff overlain by slope forming Rock Grove Formation above, which is in turn overlain by the lower biostrome of the Nora Member at the top. Photograph taken in 1967. extending south and southwest of the Winnebago Riv- er, from Owen Grove on the west (Text-fig. 16) to Rockford on the east (Text-fig. 17). To the west and northwest of Owen Grove, the dominant facies of the sequence is dolomitic, so that when the unit was seen at Mason City, all fossils were preserved as molds, and are not of interest for study of coral faunas. The stratigraphic sequence reported by Fenton and #9 #17 Baumgardner's Mill Nora Springs tbh iit) h fin Fenton (1924, p. 8) is superficially biostratigraphic, al- though not in a modern sense, as presented below un- der the heading of biostratigraphy. Fenton and Fenton divided the Cerro Gordo Member (or substage as they called it) into an upper “‘Spirifer zone” and a lower “striatula zone’. These are traceable lithic units. Each of their “‘zones’’ was divided into a series of “fau- nules’’, some restricted to a single layer, (e.g., the Lep- #23 #22 Marble Rock Roseville == 4 5@8: fo} oO o ——— ee 0-7-0 5 10-+-3 feet | meters 15 © =crinoid columnals abundant @ = massive stromatoporoids abundant -~ = laminar stromatoporoids 20-++-6 Text-figure 7—North to south cross section of the Mason City Member of the Shell Rock Formation between Nora Springs on the north and Greene (Marble Rock Quarry) and Roseville, Iowa on the south and southeast. Changes in thickness in the Mason City Member appear most closely related to variation on the basal disconformity surface. Localities shown on this section are illustrated on maps of Text-figures 3 and 4. 16 BULLETIN Ww Nn Nn Text-figure 8.—Exposures of the entire Mason City Member at Cooper’s Bend (Locality 19, Appendix). The massive dolomites forming the shelf at the base of the sequence are underlying Cedar Valley beds, with 1.3 m (4 ft) of Mason City divided into lower shaley, rubbly coral- bearing limestones and upper more massive unit, in turn overlain by slope-forming shaley beds of the Rock Grove Member under trees. Photograph taken in June, 1986. <_| Aureola Qua Greene Quad. Shell Rock River Aureola # 24 Maxson Quarry —> 3 | SS | Exposure - Shell Rock Fm. Aureola 7 1/2 Min. Quad. 0 5 1 Mile ee ed Text-figure 9 —Exposures of the Shell Rock Formation along the Shell Rock River northwest of Greene, Iowa. Further details of stratigraphic localities are noted in the Appendix tostrophia “‘faunule”’, 7.5 cm thick, which is one thin bed characterized by the small, concavo-convex bra- chiopod Nervostrophia). Such units are only locally recognizable, and are not of use as zones. Text-figure 23 shows lithologic correlations of Cerro Gordo units within sections described between Owen Grove and Rockford. Several marker beds aid in the correlation and rec- ognition of portions of the member, often allowing pre- cise placement of a very limited outcrop sequence within the stratigraphic framework of the entire unit. Remarkable uniformity exists within this member in its area of outcrop, facilitating correlation. One such bed is the “trusty” bed, shown at the base of the upper unit (““Spirifer’ zone of Fenton, 1919), at the type section in the bluffs along the Winnebago River (Lo- cality 28, Text-figs. 16,17). This bed is hematitic, due to the oxidation of pyrite on what apparently was a hard ground. It is characterized at the type section by a great abundance of stromatoporoids and stromato- poroid-coated colonies of Pachyphyllum, Hexagonar- ia, Iowaphyllum, and the tabulate genus Alveolites. The bed can be recognized as far west as roadcuts along County Highway D, south of Portland, Iowa (Locality 27, Text-fig. 16), and maintains its essentially rusty, stromatoporoidal and coralline nature eastward as far as the Cerro Gordo-Floyd County line. Although the nature of the unit is altered somewhat, it occurs as DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 7/ — Me: SS — Ui a hb See ce Text-figure 10.—Closeup of large stromatoporoid in lower Nora biostrome at level of hammer, with dolomites of the Rock Grove (?) Member underlying. Outcrop is along west side of Shell Rock River at Reed Creek, Locality 4 (Appendix). Photograph taken in 1986. a prominent limestone unit (0.7 m) at the base of the upper unit of the Cerro Gordo at the former claypit of the Rockford Brick and Tile Co. (Text-fig. 23). The strata overlying this unit and below the basal beds of the Owen Member are the source of virtually all corals from the Cerro Gordo Member. No corals, solitary or colonial, were collected from outcrops of the under- lying unit (“‘striatula zone’ of Fenton and Webster, in Fenton and Fenton, 1924, p. 8), which is characterized by an abundant brachiopod fauna and overlies the Ju- niper Hill Member, with clay nearly barren of mega- fossils. Fenton and Fenton emphasized that light tan-weath- ering shales containing a large number of Strophonel- loides and Douvillina (their Leptostrophia canace bed) is very useful for correlation of Cerro Gordo strata. It occurs approximately three meters below the top of the member. I was not able to trace this bed with con- fidence. The “‘fucoid beds” of Fenton and Fenton (1924, p.13) are also not reliable as marker horizons, as many of the sandy or shaley limestone units of the upper middle part of the member develop a similar burrowed aspect, with the trace fossil Gracilerectus Webster present at many localities. For example, 1.2 km (¥, mi) southeast of the main Bird Hill locality, an outcrop exposes equivalent beds in which three sepa- rate limestone units show extensive burrowing (Lo- cality 32, Text-fig. 17). At a hillside outcrop and road cut 0.8 km (0.5 mi) south of Locality 27 is one lime- stone bed (2 m above the “‘rusty bed’’),also extensive- ly burrowed, that could easily be mistaken for the ““Gracilerectus bed”. In summary, the Cerro Gordo Member is a sequence of calcareous shales and argillaceous nodular lime- stones, with a lower unit (approximately 4.5 m at Rockford) characterized by calcarous shales bearing abundant brachiopod faunas, and an upper unit (ap- proximately 10 m thick) characterized by an alterna- tion of calcareous shales and nodular argillaceous limestones bearing the prolific coral and brachiopod faunas of the member. This unit is overlain by the carbonate rocks of the Owen Member. Lithologies of the Cerro Gordo Member are quite constant over its limited area of outcrop (Text-fig. 23). OwEN MEMBER The type section of the Owen Member of the Lime Creek Formation appears to be somewhat unusual for this member, which can be traced south from Cerro Gordo County into Butler and Franklin Counties (Text-fig. 24). The type sequence of limestones of the basal Idiostroma beds, along with overlying soft dol- omites and dolomitic shales of the Floydia beds, is partially exposed in the western part of Section 31 of Portland Township (Locality 26 and in the eastern part of section 26 of Mason Township (Locality 25) along a small creek tributary to the Winnebago River (Text- fig. 16). The northern facies of the Mourlonia beds seen at Owen Grove also changes rapidly to the south and southwest and is developed as a biostromal facies with highly abundant Actinostroma at Rockwell and at the Lillibridge Quarry, southeast of Rockwell (locs. 36 and 38), as shown on Text-figure 24, (and localities shown in Text-fig. 25). Farther south, exposures were formerly excellent in the Buseman and Carolus quar- ries south of Dumont, Iowa (Text-figs. 26—28). BASAL BEDS (‘‘Jdiostroma zone”’ of Fenton, 1919, p. 364) Well-bedded micritic limestones containing abun- dant branching stromatoporoids (Amphipora, accord- ing to Stock, 1984, p. 128) are present in the type section at Owen Grove, and are characteristically de- veloped through all of eastern Cerro Gordo County, 18 BULLETIN 355 O77 Rock Falls 21 Wy YY 22 23 = = 28 F 27 ; See #1 Quarry <= Keidle's Bluff JL = == 25 Floyd Co Cerro Gordo Co | 4 — 34 | 35 Sherman Bluff —_}#2 Weitsie's Bluff | 36 | | c<— #4A N. Reed Creek 3 2 ZS 1 6 | | #4 Reed ee | C<— #5 S. Reed Creek z ithe Ae Sagar - =, F yi -N. Nora Springs QML 10 U.S. HWY. 18 "1 Nora Springs ¢ #7 W. Nora Springs | ae) eZ Localities Northwest of Nora Springs, lowa Shell Rock Fm. 5 1 Mile —J| Map localities from U.S.G.S. Nora Springs Quad. oan Y Will #9 Nora Ck " 13 #10 S. Nora sil W. Ww. Text-figure 11.—Localities where the Shell Rock Formation was studied along the Shell Rock River northwest of Nora Springs, Iowa. Sections 1—7 are of the Nora Member, while the lower part of the formation is also exposed in the area around and to the south of Nora Springs. Further details are to be found in the Appendix. capping hills developed on the calcarous shales and argillaceous limestones of the Cerro Gordo Member. The Amphipora beds are seen at Bird Hill, Hackberry Grove, and in all intervening areas. The same facies also occurs at the Morgan Quarry in northeastern Franklin County (Text-fig. 29), with thinner, but iden- tical Amphipora-bearing limestones forming the base of the Owen Member. Farther south, in Butler County, argillaceous micrites apparently contain Amphipora, but these beds differ from the more typical basal Owen in that they weather to a recess below more massive overlying beds and contain branchng bryozoans and Amphipora (see Buseman and Carrolus sections, Text- figs. 24,26—28). DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 19 al #2 #3 #4 Bjorgason Weitsie's Bluff Quarry North of Keidle's Bluff Reed Creek #5 #6 m=O S. Reed Creek N.Nora Springs Nora (# = Massive stromatoporoids ~ = laminar stromatoporoids Rock Grove Member Text-figure 12.—Stratigraphic section illustrating changes in the Nora Member in a northwest to southeast traverse along the Shell Rock River north of Nora Springs, Iowa. Localities are those first studied by Belanski, and further information on localities is shown on Text-figure 6, and listed in the Appendix. MIDDLE BEDS (*‘Floydia zone”’ of Fenton and Fenton, 1924, p.8) The Floydia beds, named for their fauna of large gastropods, are variable in the area studied. At the Owen Grove type section, these soft brown dolomites are poorly exposed. To the southwest at Rockwell, in the abandoned quarry which serves as the town dump (Locality 36, Text-figs. 24,25), the lower 2 m of the unit is composed of a biostrome with highly abundant stromatoporoids comprising up to 99% of the rock. Above are found bedded argillaceous dolomites with a very abundant fauna of Hexagonaria bassleri in the uppermost 0.5 m. This upper unit changes very shortly to the south, and in Linn Grove Park, in the town of Rockwell, two abandoned quarries show up to 3.2 m of biostromal beds (Locality 37, Text-fig. 25). This facies change takes place in approximately 1.2 km (0.75 mi). The biostromal facies of the Floydia beds are best shown at the Lillibridge Quarry, south-southeast of Rockwell, where stromatoporoids account for virtually all of the volume of the main biostrome (4 m thick, Text-fig. 24). To the southeast, at Morgan Quarry in Franklin County (Text-figs. 24,29), Floydia beds are rather dif- ferent in aspect. The lower 2.1 m of the unit are com- posed of calcareous shales and cross-stratified biomi- crite bearing a fauna of Pachyphyllum, Tabulophyllum, Cyrtospirifer, and crinoid columnals. This unit is rep- resented by burrowed micrites farther southeast at the quarries located south of Dumont in Butler County. Southeast of the thick biostromal development in the Rockwell area, fossiliferous micrites and coarser bioclastic limestones comprise the upper part of the Floydia beds. This unit contains abundant subspherical Text-figure 13.—Nora Member at Weitsie’s Bluffs, Locality 2 (Appendix), with thick massive carbonate facies of complete(?) Nora sequence, which here lies directly on pre-Shell Rock beds. Photograph taken in 1986. 20 BULLETIN 355 NorthWest #2 #5 Weitsie's Bluff Reed's Creek #12 SouthEast , Rudd fx 2), on 6.7 mi ——__>| Upper Biostrome 0 0 ee a [53 E> 3 10 #13 #14 West 5.5 mi. _—— a a Lower Biostrome East 4 mi, —————w Upper Biostrome — Lower Biostrome \ \\\ = cross-stratified ~~ = laminar stromatoporoids Text-figure 14.—Two stratigraphic sections of the Nora Member are shown; the upper secton illustrates stratigraphic changes as one traverses away (east) from the more massive calcareous facies of the Nora, as would be seen in the subsurface shortly to the west of the outcrop belt. The lower section illustrates similar facies changes from Portland to Rockford, with a similar more distinct development of the two biostromes of the Nora Member in the eastern area (Localities are shown on Text-figures 3,11). Rockford Quad Exposure - Shell Rock Fm. Rudd 7 1/2 Min. Quad. 0 5S 1 Mile Text-figure |5.—Location of exposure of Nora Member at Rudd, Iowa. Further details are in the Appendix. stromatoporoids and at several levels is biostromal in aspect (Text-fig. 24). This is the source of much of the coral fauna of the lower part of the Owen Member. The upper portion of this middle unit is generally speaking, dolomitic and argillaceous. The unit is soft, and weathers into slopes between the carbonate units below and above. It is characterized by gastropod and pelecypod faunas and characteristic spiriferid and cho- netid brachiopods. Its soft, dolomitic nature makes it an easily recognizable unit where it is exposed. UPPER BEDS (“‘Acervularia zone”’ of Fenton, 1919, p. 366) This thin unit of light gray-weathering micrites is easily recognized and bears the most abundant coral faunas of the Owen Member. An average thickness approximates that seen in western Owen Grove, where well-exposed beds are 0.9 m. The unit is never thick, but has been the source of most of the coral species described from the Owen Member. The single expo- sure that contributed most specimens is the now-aban- DEVONIAN RUGOSE CORALS OF IOWA: SORAUF PAI Nora Springs Quad. | i Mason City SE Quad. Outcrop localities Cerro Gordo County, lowa Lime Creek & Shell Rock Fms. 24 19 20 | 21 #13 es Quarry ‘s 25 30 29 te, 28 27 #27 South Portland [<—#27A she Portland 32 33 Zz Ro #26 Owen Grove Hanford Quad. Mason City SE Quad. | | #28A W. Hackberry Grove 26 | #28 Type Lime Creek | #28B E. Lime Creek L5 Pp 4 A 25 Cerro Gordo Co. Floyd Co. 34 35 36 31 #14 County Roads Quarry G T. 96N. T.95N. | #29 County Line Road North ] : 3 | 2 | 1 6 Cerro Gordo Co. Floyd Co. #30 bi Hill North 2 ee Text-figure 16—Outcrop localities of the Lime Creek and Shell Rock Formations along the Winnebago River and its tributaries. Section number 28 is the type section for the Cerro Gordo Member of the Lime Creek and number 26 is the type locality for the Owen Member. Further information is in the Appendix. doned quarry in Owen Grove (Locality 26, Text-fig. 16). Stripped surfaces at the Lillibridge Quarry south- east of Rockwell (Locality 38, Text-fig. 25) provided very abundant specimens of Hexagonaria bassleri and Pachyphyllum crassicostatum as well as numerous tab- ulate and solitary corals. BIOSTRATIGRAPHY The Lime Creek corals have long been regarded as one of the major Frasnian coral faunas of the world, but it is only during the past decade that an easily correlated zonation of the Shell Rock and Lime Creek beds has been worked out, primarily on the basis of conodonts and brachiopods. The coral faunas of the Shell Rock and Lime Creek Formations are not nearly as useful as conodonts or brachiopods for zonation of these strata, but are listed in Table 2 with their strati- graphic position in the major subdivisions of the se- quence. Unit 1 shown on Table 2 is the Mason City Member of the Shell Rock, which Day placed in his Tenticospirifer shellrockensis Zone and the lowermost part of his Strophodonta cicatricosa Zone (1989, 1996). Corals generally derive from lower, biostromal beds with abundant stromatoporoids, but abundant cor- als are also found within soft limestones in the upper- most part of the Mason City Member. Unit 2 contains the lower and upper biostromes of the Nora Member, placed in the Strophodonta cicatricosa Zone (Day, 1989, 1996). Both biostromes contain abundant corals and stromatoporoids. Within the Lime Creek Forma- tion, Unit 3 of Table 2 is the Cerro Gordo Member, but in actuality all of the Cerro Gordo corals come from the upper part of the member which Fenton and Fenton called the “‘Spirifer zone”’ (1924), the Cyrtos- | | #29 County Line Road North 6 R19 W. R.18W. #30 Bird Hill North ill North | BULLETIN 355 ? Outcrops of the Lime Creek Formation Cerro Gordo & Floyd Counties I o< | #34 Juniper Hill | g yi ncaa | ik 13 5 a 18 17 | Me | #31 Bird Hilly ers | WY, : ZZ rowel / | PN Hye Yd #36 West eS La #37 Linn Grove | t, Ut VAY | "1 U.S. HWY. 65 Exposures - Owen Mbr. Lime Creek Fm. SEM 7 We Min. Quad. 1 Mile | | | =a | ai Lillibridge ee | » 4 27 Slime | a edt Zire, eaten es ae | | 34 | 35 | | | Cerro Gordo Co. Franklin Co. | | Text-figure 25.—Exposures of the Owen Member of the Lime Creek Formation in the Rockwell area, north of Sheffield, Iowa, in southernmost Cerro Gordo County. Exact geographic localities are shown, additional data is in the Appendix. Iowa City (SUI). Specimens from Webster’s private collection and some types from the present study are deposited at the Natural History Museum of the Smith- sonian Institution in Washington, D.C. These have numbers referring to the United States National Mu- seum (USNM). Several specimens referred to by Be- to Dumont 4.0 Mi. eee set as Pe a | ee #40A N. Buseman Quarry 21 22 23 a #40 Buseman Quarry is. = == = Sa eae SS SS Exposures - Owen Mbr.. Lime Creek Fm. DiS South v 1/2 Min. Quad. 1 Mie tite en op aren Text-figure 26.—Location of three quarries in the Owen Member, located due south of Dumont, in Butler County, Iowa. Additional information is listed in the Appendix. lanski (1928) are in the University of Cincinnati Mu- seum (UCM). Additionally, some types and illustrated specimens have been deposited at the Paleontological Research Institution, Ithaca, New York (PRI). SYSTEMATICS Class ANTHOZOA Ehrenberg, 1834 Subclass RUGOSA Milne-Edwards and Haime, 1850 Order STAURIIDA Verrill, 1865 Suborder KETOPHYLLINA Zhyavoronkova, 1972 Family ENDOPHYLLIDAE Torley, 1933 The Family Endophyllidae is accepted here largely as defined by Hill (1981, p. F225), and the genus Jo- waphyllum is placed therein, as was done by Hill. However, three genera also placed in this family by Hill are removed and placed in the Kyphophyllidae, as done by McLean and Pedder (1984, p. 18). These are the fasciculate genus Smithiphyllum and the soli- tary or sparsely colonial Tabulophyllum and Tarphy- phyllum. 28 BULLETIN 355 Text-figure 27.—Upper part of the Owen Member of the Lime Creek Formation at Carrolus Quarry, 1968 (Locality 41, Appendix). This photograph illustrates the alternating thick bedded and thinly and rubbly bedded limestones of the upper Owen. The thinly bedded units contained numerous stromatoporoids and corals. As of 1989, the quarry is unused and flooded in great part. Genus IOWAPHYLLUM Stumm, 1949 Smithia Hall and Whitfield, 1873, p. 234 (not Milne-Edwards and Haime, 1851). Strombodes Fenton and Fenton, 1924, p. 43. Towaphyllum Stumm, 1949, p. 50; Hill, 1956, p. F302; Stumm, 1964, p. 48; Strusz, 1967, p. 430; Oliver and Galle, 197 1a, p. 213; Oliver and Galle, 1971b, p. 82; Coen-Aubert, 1974, p. 30; Fontaine, 1977, p. 473; Oliver, 1978, p. 799; Hill, 1981, p. F229; Sorauf, 1988, p. 166. Type Species.—Smithia johanni Hall and Whitfield, 1873, original designation by Stumm (1949, p. 50). Diagnosis.—Massive aphroid coralla, corallites with septa long and attenuate in tabularium and strongly dilated at margin of dissepimentarium. Septa then ei- ther 1) continue as dilated trabecular ridges to adjacent corallites as “septal crusts’, or 2) die out as lonsda- leoid septa into areas of large and irregular dissepi- ments that separate corallites. Seen in longitudinal sec- tion, these conditions alternate in most coralla, so that septa are discontinuous in the dissepimentarium. Cor- Text-figure 28.—Complete sequence of the Owen Member of the Lime Creek Formation at the Buseman Quarry, south of Dumont, Iowa (Locality 40, Appendix). This photograph, taken in 1968 when quarry was being actively worked, illustrates the Owen, from ap- proximately 1 ft (30 cm) above the Cerro Gordo to its top under the grass at the top of the picture. The uppermost limestones are of the “Acervularia”’ zone containing abundant colonial corals. allites raised; thus, in planar transverse section aphroid appearance is emphasized. Tabulae divided into ele- vated axial and downwarped periaxial series. Wall-like surficial partitioning between corallites present in some species; likewise considerable variation in de- velopment of septal stereome between corallites. Discussion.—Stumm (1949, p. 50) proposed the ge- nus name for massive colonial corals with the type species Smithia johanni Hall and Whitfield, 1873. Stumm noted that septa could be in lateral contact across the wide dissepimentaria and that there was an apparent “‘repeated rejuvenescence”’ seen in longitu- dinal section. This “‘rejuvenescence”’’ appears as ver- tically superposed zones of stereoplasm separated by zones of large dissepiments (see below) and probably reflects seasonal variation in skeletogenesis. Stumm in- cluded Strombodes alpenensis Rominger and S. knotti Davis in Jowaphyllum, along with S. johanni. After descriptions of species by Fenton and Fenton DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 29 36 Bp BBaesne on | | Exposure - Owen Mbr. Lime Creek Fm. Hansell 7 1/2 Min. Quad. 0 S 1 Mie Text-figure 29.—Location of the Morgan Quarry (Owen Mem- ber). The quarry is in Franklin County, southwest of Aredale, Iowa. Additional information is found in the Appendix. (1924) and the genus by Stumm (1949), these corals have been found over a wide geographic and strati- graphic range. Strusz (1967) described a species from Lower Devonian (Emsian) rocks of Australia and Ol- iver and Galle (1971a,b) recognized two Emsian spe- cies from Czechoslovakia. Fontaine (1977) described a Lower Devonian species from the north of France, and Coen-Aubert (1974) a Frasnian species from Bel- gium. Oliver (1978) described a species from Frasnian rocks of Arizona and presented a full discussion of the stratigraphic and geographic distribution of species within the genus. Sorauf (1988) recognized J. johanni in Frasnian strata of south-central New Mexico. In addition to being important due to their geologic occurrence, these corals are interesting due to their sin- gular structural features. As noted above, septa are ver- tically discontinuous except in the area directly adja- cent to and within the tabularium, so that the appear- ance of the genus in longitudinal section is quite char- acteristic. Terminology for these septal elements is best borrowed from the cystiphyllids (McLean, 1976, p. 2) in which septal structures are described in terms of “crusts”, composed of closely packed trabeculae on the surface of dissepiments. The crusts can split into rows of radially fused trabeculae referred to by Mc- Lean as “crests” that form ridges and may appear as septa in transverse section. Jowaphyllum thus has crusts occurring periodically, in longitudinal section Table 2.—Stratigraphic distribution of species of rugose corals within the Shell Rock and Lime Creek Formations of north central Iowa. The subdivisions shown at the right are as follows: for the Shell Rock Formation are (1) the Mason City Member, and (2) the Nora Member; subdivisions of the Lime Creek are (3) the Cerro Gordo Member, and (4) the Owen Member. Shell Rock Lime Creek Biostratigraphy 1 2 3 4 Smithiphyllum belanskii Pachyphyllum websteri Tabulophyllum mutabile Tabulophyllum curtum Disphyllum floydense Disphyllum iowensis Pachyphyllum minutissima Trapezophyllum sp. Tabulophyllum buccinum Tabulophyllum n.sp. A Tabulophyllum n.sp. B Tarphyphyllum cylindricum Disphyllum conjugans xm KM MOM Macgeea concinnula Tarphyphyllum sp. Hexagonaria oweni mm mM MM MM OM OM Pachyphyllum gregarium Iowaphyllum johanni Tabulophyllum rectum Tabulophyllum ehlersi Tabulophyllum rotundum Tabulophyllum ellipticum Tabulophyllum ponderosum Tabulophyllum robustum Charactophyllum nanum Disphyllum dispassum Hexagonaria inequalis Pachyphyllum woodmani mm OO OM OM OM Macgeea solitaria Disphyllum sp. Hexagonaria bassleri Tabulophyllum longum Tabulophyllum magnum Tabulophyllum expansum Pachyphyllum dumonti Pachyphyllum crassicostatum mm mM MM Macgeea camplanulata separated in vertical sequence by layers of dissepi- ments that are commonly large and globose; these crusts are vertically continuous and form septa only in the area directly around and within the tabularium. Seen in transverse sections, Jowaphyllum generally ap- pears to be aphroid, as recognizable septal “‘crests” adjacent to tabularia are not continuous from one cor- allite to another. Since corallite tabularia tend to be elevated, part of the apparent aphroid nature of septa is due to intersection of a curving plane of septal crusts by a flat thin section. Seen in longitudinal section, crusts are commonly, although not always, continuous from one corallite to another. Thus the term “‘aphroid”’ 30 BULLETIN 355 applied to Jowaphyllum, has a slightly different mean- ing than when applied to genera with more typical, fully formed septa. Some specimens of Jowaphyllum are also aphroid in the usual sense, with crusts not continuing from one corallite to the next. A number of methods exist for differentiating be- tween species of Jowaphyllum within a sample such as that collected from the Lime Creek Formation. All specimens have been collected from the same horizon within the Cerro Gordo Member, from a silty lime- stone that weathers iron-stained and exhibits extensive burrowing in its upper part. Literature on the genus, and on colonial corals in general, suggests that a list of criteria for species differentiation would include the following (listed from most generally used to most specific to this genus): diameter of tabularium, number of septa, distance between corallites, measured from axis to axis, 4. presence and amount of stereome within coral- lum, 5. presence of elevated margins around tabularia, and 6. presence of a ridge serving to separate corallites, thus acting as a temporary corallite wall. WN Criteria are here reviewed from the bottom upwards. The presence or absence of a ridge forming a “‘wall’’, a polygonal margin to individual corallites on the oral surface, is a variable phenomenon within the Iowa fau- na. It is noted in many specimens of /. johanni, in- cluding a weak but persistent development in the ho- lotype. The feature is seen in longitudinal sections of the species, particularly occurring in those colonies that appear to contain abundant and widespread ster- eome in transverse section. This seems to be related to the development of thick, crested (‘‘septate’’) ster- eome mats between corallites. The development of this stereome apparently favors structural partitioning of corallites by ridge formation. The occurrence of the two features (stereome mats and ridges) is nearly ran- dom in the Lime Creek fauna, and does not suffice to differentiate species in this fauna. Where consistently and prominently developed, as in Jowaphyllum nisbeti Oliver, 1978, the character does serve to define a spe- cies. That part of the corallite immediately surrounding the tabularium in Jowaphyllum is generally elevated somewhat above the rest of the corallite surface. Well- developed relief of this type led Hall and Whitfield to erect the species Smithia multiradiata, and the devel- opment of distinct, wall-like ridges surrounding cor- allites led Fenton and Fenton to propose the species Strombodes marginatus. The two species, as originally proposed, were based on characters observable on free-weathered corallite surfaces, and there is consid- erable variation in these features in the two holotypes. In the Lime Creek fauna collected for this study, many specimens have come from the “‘rusty bed”’ of the Cer- ro Gordo Member, with a maximum outcrop separa- tion of less than 10 km (6 mi.). The presence and form of the peri-tabular boss varies within this local fauna and apparently does not correlate with other charac- ters. The amount of stereome within coralla permits grouping specimens. Stereome occurs as mat-like, in- flated, laterally coalesced septal crusts that are some- times confluent between tabularia. Since these mats are vertically discontinuous, care must be taken to com- pare thin sections taken from equivalent positions within colonies, as sections taken between layers of stereome show large dissepiments dominating areas between corallites. However, regardless of position of section, J. johanni still contains some colonies with little stereome, and some with very widespread and thick deposits of septate stereome. I consider this to be variation of colonies within the one species. Distance measured from corallite axis to that of each neighboring corallite within colonies has been used to differentiate species of Jowaphyllum by Oliver (1979, p. 799). Measurements by me indicate that there is a marked effect on measured distances by position with respect to growth of the colony. Distance between cor- allites varies as colony shape varies, and also varies with corallite position within the colony between means derived from corallites in central positions with- in a colony and means derived from peripheral coral- lites in the same colony. Extreme care must be used when comparing these mean distances between colo- nies. The number of septa is a useful character for species discrimination. In Jowaphyllum, the number of septa in a corallite correlates to the diameter of the corallite, with larger diameter corallites accommodating larger numbers of septa. There does seem to be a character- istic mean number of septa for each species. Diameter of corallites is a basic character used in speciation. In the Lime Creek fauna, Jowaphyllum is differentiated into two groups, one of which has con- sistently larger corallite diameters. The absence of oth- er characters allowing differentiation of species con- sistent with those based on size suggests to me that the differences are not of specific rank. The two sizes are here regarded as variants of Jowaphyllum johanni, and names should not be given to them. Distribution.—lowaphyllum occurs in Lower or Middle Devonian strata of Australia, the Bohemian DEVONIAN RUGOSE CORALS OF IOWA: SORAUF Bil massif, and occurs widely in Frasnian rocks of North America and Europe. It is known from Arizona, New Mexico and Iowa in North America and from the Ar- dennes and Rhenish Massif in Europe. Iowaphyllum johanni (Hall and Whitfield, 1873) Plate 2, figures 6,7; Plate 4, figures 1—7; Plate 5, figures 1—6; Plate 6, figures 1—3 Smithia johanni Hall and Whitfield, 1873, p. 234, Pl. 9, fig. 10. Smithia multiradiata Hall and Whitfield, 1873, p. 234. Strombodes johanni Fenton and Fenton, 1924, p. 43, Pl. 15, figs. 6-7. Strombodes johanni multiradiata Fenton and Fenton, 1924, p. 44, PISS tigen le Strombodes marginata Fenton and Fenton, 1924, p. 44, Pl. 15, figs. 2-S. Towaphyllum johanni Stumm, 1949, p. 50, Pl. 25, figs. 1-5; Oliver and Galle, 1971a, p. 212, Pl. 4, figs. 1-4; Sorauf, 1988, p. 166, figs. 12.3-12.6, 14.1-14.3; McLean and Sorauf, 1989, p. 395, figs. 1,2. Towaphyllum sp. cf. I. johanni Oliver, 1978, p. 800, figs. 4a-b. Diagnosis.—Species of Jowaphyllum with variable calicinal features, namely, amount of stereome present as septal crusts, size of tabularium and distance be- tween corallites. Colony mean diameter of tabularium varies from 15 to 19 mm. Septal crusts may be only sporadically present, or developed so that more than 75% of surface area is stereome in transverse section. Dissepiments generally low and flattened but can be extremely large and irregularly bulbous where stereo- me is lacking; only two or three dissepiments separate tabularia of neighboring corallites. Description.—On weathered calicinal surfaces of colonies, septal crests are commonly seen on the ster- eome crust, thus surficially resembling thamnasterioid colonies, with crests confluent from one corallite to the next. A weak ridge sometimes forms where an inter- corallite wall would occur. The surface prominence of the area surrounding the tabularium often is little de- veloped in this species, being only 1—2 mm high in the holotype of J. johanni, only /, the height described in Strombodes marginatus by Fenton and Fenton (1924, p. 44). In transverse thin sections of typical J. johanni, ma- jor septa are long, reaching to the axis of the corallite and joining in an irregular fashion. Minor septa are short; generally the tabularium is completely ringed by solid stereome without extension of minor septa into the tabularium. In intercorallite spaces, septal crests are much in evidence as lines of trabeculae within crusts composed of stereome and trabeculae. In the holotype, there is considerable development of septate crests around each corallite, with only /, to /, of total intercorallite space occupied by dissepiments of vari- ous sizes and shapes (PI1.4, fig.1). Several corallites are completely joined by these septal crests. In longitudinal section, the tabularium shows dis- tinct axial and periaxial series of tabulae, with the axial row arched in the adoral direction. In the dissepimen- tarium (which is coextensive with the intercorallite space or coenosteum) episodic development of septa is well-displayed, with septal crests formed of verti- cally directed trabeculae. The stereome surface is per- pendicular to the trabeculae (P1.4, figs.2,6). The epi- sodic (perhaps periodic) development of these septate mats of stereome was referred to as “‘repeated reju- venescence” by Stumm (1949, p. 50). Arching of the upper surface of crests near the tabularium leads to a very slight divergence of trabeculae. The dissepiments between septal crusts are irregular in size and number, comprising a layer, generally of four to seven rows, separating neighboring tabularia. The term ‘‘aphroid”’ is not totally appropriate to describe the appearance of this colony, as septal crests are continuous between tabularia. The rise in the surface of the crust near a tabularium results in the more common appearance of septal crust near tabularia in a planar thin section, and the crust may not be visible farther out in the disse- pimentarium. Type Specimens.—Holotype NYSM 3720/1; the la- bel notes that the specimen was collected from “marly beds at Hackberry, eight miles above Rockford, Iowa”’ (Hall and Whitfield, 1873, p. 234). This is Locality 28 of the present study (see Appendix). Smithia multira- diata holotype is NYSM 3721/1. Strombodes margin- atus holotype is FMNH 26053, paratype is UMMP 8087. Discussion.—It is convenient to recognize within the Iowa fauna two forms, here informally called the Johanni and multiradiata groups. I separate the two on the basis of the colony mean diameter for the tabular- ium, with johanni s.s. being characterized by a con- sistently smaller diameter of tabularium (with a mean ranging from 2.9 to 3.8 mm (Text-fig. 30). The holo- type of the species has a colony mean of 2.9 mm. Those corals referred to as the multiradiata group are somewhat larger, with mean tabularial diameters rang- ing from 3.9 to 4.6 mm per colony. The size ranges form a continuum. Within /. johanni, groups of colonies illustrate the variation present within the species. At one end of the scale of variation are a number of colonies marked by the standard size tabularium (for the form), with minor amounts of stereome occurring as septal crusts (P1.4, fig.4), and a wide dissepimentarium which may have very large dissepiments (PI1.4, fig.5). This is character- istic of the holotype of Strombodes marginatus Fenton and Fenton (PI1.4, fig.5; P1.5, fig.5). The large, bulbous dissepiments are quite characteristic of this subgroup, which grades into a second, with large dissepiments eS) i) 45 lowaphyllum johanni A qeSseeiccich oad Colony Mean Number of Septa & t \ \ 1 1 ' t ' t r r L Il t n 1 r 1 1 It 1 1 1 ' ' ' t ' Ssrssosse= ee ee t 1 I 1 \ 1 ' 1 ' ' I ' ' 1 1 r r It 1 1 It r holotype - S. marginatus | : —= . : holotype - S. multiradiata \ ' T r 25% - ; t — 25 3 3.5 4 45 5 Colony Mean Diameter of Tabularium - mm Text-figure 30.—Jowaphyllum johanni, trom the Cerro Gordo Member, colony mean diameters (in mm) plotted versus the colony mean number of total septa (major and minor). The holotype colo- nies of Strombodes marginatus Fenton and Fenton and Smithia multiradiata Hall and Whitfield are also shown on this graph. and a standard size tabularium, but with septal crusts (stereome) much more obvious in transverse section (P1.5, fig.6). A third group of these colonies includes those with standard tabularium diameter, but with the heavy de- velopment of septal crusts (PI.5, fig.2). In longitudinal section, these corals generally do not show elevated margins around the tabularia, but may in some cases show weak development of the ‘‘wall-like” ridge marking what would be the boundary of individuals. The holotype of /. johanni has such ridges weakly de- veloped. They are observable on the weathered cali- cinal surface and occasionally in thin section. The fea- ture is better developed in some other specimens where it can be seen in transverse thin sections as straight-line margins to areas of stereome and as dis- continuous vertical prominences in longitudinal sec- tion (PI. 5, figs.2,3; P1.6, fig.3). These ridges are never as continuously or fully developed here as in /. nisbeti Oliver, from Frasnian rocks in Arizona (Oliver, 1978, p. 799). One paratype specimen (UMMP 8086) of Strombodes marginatus Fenton and Fenton also be- longs in this third grouping, as it is characterized by a high prominence surrounding the margin of the ta- bularium and a weak wall-like ridge. The /. multiradiata group shows a similar pattern of variation, but is characterized by larger tabularial di- ameters. There are two intergradational clusters, one characterized by a general lack of stereome, with dis- sepiments that are extremely large and irregular (PI1.5, fig.5), and a second, also with a similarly large tabu- larium, but with fuller development of septal crusts. A prominence is variably developed around the margin BULLETIN 355 of the tabularium, but where developed, tends to be smoothly rounded, rather than being somewhat abrupt as in J. johanni s.s. This last includes the holotype of Smithia multiradiata Hall and Whitfield (NYSM 317), and also one of the paratypes of Strombodes margin- atus Fenton and Fenton (UMMP 8087). To summarize the preceding: 1) there does not seem to be a straightforward way to divide this fauna into more than one species, and 2) although specimens can generally be placed in the one group or the other by the average size of their corallites, this is within a size continuum. Each size group shows parallel change from forms with large irregular dissepiments and weakly developed septal crusts to colonies with heavi- er septal crusts and sometimes with elevated margins around the tabularium as well as the weak develop- ment in some specimens of a wall-like ridge from the septal crust. Thus, I place the species Smithia multi- radiata Hall and Whitfield, 1873, and Strombodes marginatus Fenton and Fenton, 1924, into synonymy with Jowaphyllum johanni (Hall and Whitfield, 1873). Smithia multiradiata corallites are characterized by a distinct, smoothly rounded prominence centered on the tabularium. The feature is well shown in the ho- lotype (NYSM 3721/1; P14, fig.3). As noted previ- ously, the calicinal boss surrounding the tabularium is variable within Jowaphyllum johanni, and the holotype of I. multiradiata is similar in all ways to other typical specimens of /. johanni that have heavy development of septal crusts but lack wall-like ridges (PI.5, fig.6). The tabularial diameters in the holotype of S. multi- radiata are larger than typical, with a mean of 4.2 mm, but, as discussed above, this occurs within the contin- uous size variation of /. johanni. Strombodes marginatus was proposed by Fenton and Fenton (1924, p. 44), on the basis of the presence of calicinal bosses centered on the tabularia, with the “area about the depression sharply elevated, in some specimens as much as 2.5 mm above the general sur- face of the corallite, which is convex”’, and with septa that are “strongly flexuous and are elevated at the pe- riphery to form distance boundaries for the corallites” (1924, p. 45). None of these coral colonies were thin- sectioned until the present study. The holotype (FMNH 26053) is a typical member of the /. johanni species group, characterized by light development of septal crusts, a small mean size of tabularial diameter (3.74 mm), and a sharply raised rim around the tabu- larium, but with no development of a wall-like ridge between corallites. The two paratypes vary in size, one with small tabularial diameters (mean, 3.5 mm, UMMP 8086) and the other large (mean, 4.55 mm, UMMP 8087). Each has an elevated area around the margin of the tabularium, and each shows the weak DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 33 development of a wall-like ridge between some cor- allites. The ridge here is little more developed than in the holotype of J. johanni. The species /. marginatus is a synonym of /. johanni. Iowaphyllum johanni has also been reported from the Martin Limestone (Frasnian) of Arizona by Oliver (1978, p. 800), who briefly described and illustrated his specimen as J. sp. cf. 1. johanni, which I accept as I. johanni. It is also common in the Sly Gap Formation (Frasnian) of south central New Mexico (Sorauf, 1988, p. 166). Occurrence.—Fenton and Fenton (1924, p. 43) not- ed that Jowaphyllum johanni occurs in the ““Upper por- tions of the Spirifer zone and the Owen’’. They also stated that their species, Strombodes marginatus, here regarded as synonymous with the former, likewise oc- curs in “‘Upper portions of the Spirifer zone and prob- ably in the Owen. It is especially characteristic of the Stromatoporella faunule at Hackberry Grove” (1924, p. 45). All specimens from Fenton collections at UMMP and FMNH are labeled as coming from the “Spirifer zone” at Hackberry Grove (Locality 28 of this study, Appendix). My experience is that all spec- imens of Jowaphyllum occur in a single bed, the “‘rusty bed” of the medial Cerro Gordo Member, in which they are found with abundant stromatoporoids, the ru- gosans Hexagonaria inaequalis, and Pachyphyllum woodmani, as well as the tabulate Alveolites rockfor- densis. This is also the only level at which the stro- matoporoids and this species of Hexagonaria are found. Approximately 20 colonies of Jowaphyllum were noted, always in this bed, at South Portland (Lo- calities 27 and 27a, Appendix) and from type Lime Creek strata (Locality 28). In 1986, the best place to collect abundant Jowaphyllum was at Locality 28B, Lime Creek East, where annual plowing of a corn field exposes many colonial corals from this level of the Cerro Gordo Member. Most certainly the species does not extend into Owen beds. Family KYPHOPHYLLIDAE Wedekind, 1927 The Kyphophyllidae, as discussed by McLean and Pedder (1984, p. 18), includes genera characterized by very fine septal trabeculae, vertically elongate dissep- iments and presepiments, and a distinctive tabularium with flat or arched tabulae. Among others, these au- thors included the genera Tabulophyllum, Tarphyphyl- lum, and Smithiphyllum, all of which occur in the lowa Frasnian. I adopt their concept of the family, finding that these genera have much in common. Hill (1981, p. F223) previously defined the family quite differently from McLean and Pedder. She re- garded the family as containing genera with small, multiserial septal trabeculae. In other criteria, the fam- ily as she defined it could contain Smithiphyllum and Tabulophyllum. Genus TABULOPHYLLUM Fenton and Fenton, 1924 Chonophyllum Hall and Whitfield, 1873, p. 233; Fenton and Fenton, 1924, p. 29. Tabulophyllum Fenton and Fenton 1924, p. 30; Stumm, 1940, p. 60; Smith, 1945, p. 58; Stainbrook, 1946, p. 416; Stumm, 1949, p. 27: Soshkina, 1951, p. 34; Bulvanker, 1958, p. 162; Watkins, 1959, p. 81; (part) Soshkina, 1960, p. 290; Spassky, 1960, p. 25: Pitrat, 1962, p. 1159; Stumm, 1962b, p. 292; Soshkina, Dobro- lyobova, and Kabakovich, 1962, p. 342; Ivania, 1965, p. 24; Tsien 1969, p. 37; Hill and Jell, 1970, p. 63; Tsien, 1976, p. 266; Spas- sky, 1977, p. 115; Birenheide, 1978, p. 64; Rozkowska, 1980, p. 42; (part) Onoprienko, 1979, p. 29; Hill, 1981, p. F229; Coen- Aubert, 1982, p. 37; Sorauf, 1987a, p. 16; 1987b, p. 677; 1988, p. 158; 1989, p. 397. Apolythophyllum Walther, 1928, p. 135. ?Sinospongophyllum Yoh, 1937, p. 56; Hill, 1942, p. 20; Fontaine, 1966, p. 62: Strusz, 1967, p. 431. Eurekaphyllum Stumm, 1937, p. 431; Stumm, 1949, p. 17. Diversophyllum Sloss, 1939, p. 65; Stumm, 1940, p. 58; 1949, p. 25. Type Species.—Tabulophyllum rectum Fenton and Fenton, 1924, p. 31. Diagnosis.—Solitary kyphophyllid corals of vari- able size (small to large) characterized by amplexoid septa in two orders. Major septa commonly long, ex- tending to near axis of corallite, but generally leaving open axial space, which lacks an axial structure. Minor septa always short, commonly discontinuous in dis- sepimentarium, only short spines in some species. Lonsdaleoid dissepimentarium present to variable ex- tent in all species, with presepiments interrupting septa in outer dissepimentarium. Tabulae commonly com- plete and flat in tabularium, with peripheral sag caus- ing gutter-like structure. Septa with fine monacanth trabeculae. Corals substrate adaptive, with prominent talons developed on hard substrate and multiple thin, leaf-like presepiments formed on very soft substrates. Discussion.—Tabulophyllum was established by Fenton and Fenton in 1924, with Tabulophyllum rec- tum the type species. The species, as here defined, is more inclusive than as described by Fenton and Fen- ton, who based species descriptions narrowly, on fea- tures that commonly change as ecological adaptations. In general, the genus comprises two groups of spe- cies, one with medium to small corallite diameters and the other with large diameters. The former tend to be somewhat generalized corals without marked symme- try or specialized structures, but with great variation in form according to ecologic circumstances, as in Ta- bulophyllum rectum. The latter tend to develop bilat- eral symmetry, a shortened cardinal septum, and dif- ferential septal dilation in the cardinal quadrants. The 34 BULLETIN 355 latter are typified by the species Tabulophyllum lon- gum and T. magnum of the Owen Member of the Lime Creek Formation, both of which are large and vary from corallites with no bilaterality to individuals with it well-developed and often accompanied by shorten- ing of the cardinal septum. When septa are long, these large corals may have an axial boss formed by swirling of septa around the corallite axis. The microstructure of septa and tabulae is finely tra- becular and fibronormal when best preserved (Sorauf, 1989, p. 401). The corallite wall is a septotheca formed of the expanded and coalesced bases of septa, com- posed of fibrous crystallites, but commonly modified into a secondarily lamellar wall structure by diagenesis (Sorauf, 1996, p. 69). Species of Tabulophyllum also show apparent ad- aptations to differing substrates, as follows: apical tal- ons developed, probably to form a wide base on hard substrate; leaf-like presepiments developed, possibly to provide stability on, or in, very soft substrates; and there is a suggestion that secondary calcite deposited in the apices of corallites may have provided added stability in shifting substrates. Several of these possi- bilities are discussed below in species descriptions. All authors are agreed that Apolythophyllum Wal- ther, 1928 is a synonym of Tabulophyllum, following the lead of Lang et al. (1940, p. 18). This agrees with Hill (1981, p. F229). Diversophyllum Sloss, 1939 is also a synonym of Tabulophyllum, although Sloss (1939, p. 66) regarded it as separate because of what he termed ‘‘definite and persistent minor septa’. Wat- kins (1959, p. 82), studied material from Middle De- vonian beds in Michigan, and concluded that the two genera are similar internally and thus regarded them as synonyms. I have studied numerous topotypes of Diversophyllum traversense, type species of the Sloss genus, and regard them as Tabulophyllum without question. Minor septa are no more continuous in this species than in typical Tabulophyllum. Hill (1981, p. F230) placed this genus into synonymy with Tabulo- phyllum with a query, which is unnecessary. Sinospongophyllum Yoh, 1937 was established for solitary corals with flat tabulae and an “inner wall” which separated the lonsdaleoid part of the corallite from the inner (Yoh, 1937, p. 56). Wang (1948, p. 31) noted that the type species, S$. planotabulatum, con- tains mostly solitary corals, but that the species is “sometimes weakly compound’. Wang here authored two other species that are strictly solitary. Uncertainty regarding the possibly colonial nature of Sinospongo- phyllum is the only reason for querying the placement of this genus as a synonym of Tabulophyllum, as has Hill (1981, p. F230). It should be synonymized if S. planotabulatum is only occasionally compound, as nu- merous solitary genera of the Rugosa occasionally bud. Soshkina (1951) and Bulvanker (1958) both have included colonial species in Tabulophyllum, T. weberi by the former, and 7. sibericum, T. butovi and T. schlii- teri by the latter. This is an unacceptable change in the genus concept based on the Iowa fauna. Distribution.—The geologic range of Tabulophyl- Jum is from the Pragian, in the Mt. Etna Limestone of Queensland (Strusz, 1972, p. 447) to questionably ear- ly Famennian and very questionably late Famennian. Although Hill (1942, p.20) described the early species as Sinospongophyllum abrogatum, she noted that the genus might be identical to Tabulophyllum. Species of Tabulophyllum are abundant in highest Lower Devo- nian strata of Europe (Tsien, 1969) and are present and characteristic worldwide in Middle and lower Upper Devonian rocks. The cosmopolitan Frasnian faunas are similar worldwide to those of Iowa. Reported Famennian occurrences of the genus can be discounted in part. The report of Tabulophyllum maria from early Famennian rocks of Moravia in the Czech Republic (Galle, 1987) however, is apparently valid (depending on dating of strata); this and a pos- sible Famennian occurrence of 7. gorskyi in Poland (Rozkowska, 1969) would mean that species of this genus survived the late Frasnian extinction event. It appears unlikely that late Famennian (Strunian) spe- cies are properly placed in this genus (Onoprienko, 1979; Poty and Onoprienko, 1984). No Lower Car- boniferous species are referable to Tabulophyllum, al- though Soshkina (1960) argued otherwise. Further dis- cussion is presented in Sorauf (1989). Tabulophyllum rectum Fenton and Fenton, 1924 Plate 1, figure 9; Plate 6, figures 4—10; Plate 7, figures 1—S Tabulophyllum rectum Fenton and Fenton, 1924, p. 30, Pl. 6, figs. 8-12; Smith, 1945, p. 58, Pl. 2, figs. 10,11; Pl. 3, fig. 8; Stumm, 1949, p. 69, fig. 18; Hill, 1956, p. F300, fig. 205,c,d; Watkins, 1959, p. 81, Pl. 16, figs. 10-12; Hill, 1981, p. F229, figs. 2a,b; Sorauf, 1989, p. 402, figs. 1-4. Tabulophyllum regulare Fenton and Fenton, 1924, p. 33, Pl. 6, figs. eZ? Tabulophyllum erraticum Fenton and Fenton, 1924, p. 36, Pl. 6, figs. 3-7. Diagnosis.—Small species of Tabulophyllum with 30 to 35 major septa and discontinuous minor septa developed as septal spines. Attenuate major septa reach near axis but do not unite or form axial structure. Lonsdaleoid dissepimentarium variably developed, commonly narrow, but expands and contracts regular- ly. Tabulae commonly complete, forming flat, raised platform throughout most of tabularium, with periph- eral trough formed of downbent edges of tabulae. Description.—Tabulophyllum rectum, type species DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 385 of the genus, is small and is rounded to slightly ovoid in outline, generally with a trochoid or irregularly elongate ceratoid form (PI.1, fig.9). The diameter is 13 to 18 mm; the holotype has a total diameter of 16 mm, and its tabularium diameter is 14 mm. Major septa are attenuate and long, reaching into the axial area, al- though not extending to the axis. Septa are thin throughout the corallite and are only continuous within the tabularium. Minor septa are poorly developed (P1.7, figs.2,3,4), occurring as spines in the peripheral part of the dissepimentarium, or occasionally as spines with a wedge-shaped base in the septotheca. Presepi- ments are elongate (P1.6, figs.4,6), and generally con- tinuous, interrupting both major and minor septa. The dissepimentarium is seen expanding and contracting in longitudinal section, commonly with an asymmetry in which one side contains larger and more bulbous pre- sepiments and expands and contracts more than the other side, as in the longitudinal section of the holo- type. In longitudinal view tabulae tend to be complete and flat, with a sinusoidal sag at the periphery of the tabularium. The tabularium is highly variable, ranging from one with evenly spaced complete tabulae to one with growth bands of bunched tabulae, which are less complete where closely spaced. Where very regular, these are segregated into growth bands that are uni- formly composed of flat-topped, incomplete tabulae (as in T. regulare Fenton and Fenton, 1924, p. 33). Where irregular growth has occurred, the tabulae and tabularium reflect this, with widely spaced, sloping, complete tabulae (PI.6, fig.9) formed at times of rapid growth and more typical and regular tabulae during times of slower growth (e.g., holotype of T. erraticum Fenton and Fenton, 1924, p. 36). Irregular growth is likewise shown by contraction and expansion of the dissepimentarium, apparently reflecting the response of a polyp to changing environmental conditions. The external form of the species is variable, with the shape seemingly controlled by environment, in part resulting from direction of growth and in part con- trolled by expansion and contraction of the dissepi- mentarium, and at the extreme resulting in laterally extended, large, leaf-like presepiments which may have aided in positioning the coral and maintaining a somewhat erect position for the polyp above the sed- iment-water interface (P1.6, fig.8). This variability has led to confusion and the multiplication of species names. Type Specimens.—Holotype UMMP 7834, para- types UMMP 7835, 7836, 7827 and FMNH 26046. 7. regulare holotype UMMP 7824, paratype UMMP 7825. T. erraticum holotype FMNH 26006, paratypes UMMP 7823, 7822, 7841, 7794, 7795, and 7796. Discussion.—The species Tabulophyllum rectum from the Lime Creek Formation is a variable form which encompasses the holotypes of Tabulophyllum regulare and T. erraticum, both described by Fenton and Fenton and partly based on growth characters. Thus, 7. rectum had a straight (erect) form with a pole as a growth axis, 7. erraticum had a twisting, erratic growth form, and 7. regulare had regular expansions and contractions of the dissepimentarium coupled with regular development of bands of closely spaced tabu- lae. Providing these characters were a response to changing living conditions, forms with very regular growth thus were most likely living on a sea floor with constant rate of sedimentation, while forms with er- ratic growth forms likely reflect episodic toppling of corals by currents at the sediment-water interface. The presence of large presepiments in this species possibly served a support function in and on soft substrate. Tabulophyllum rotundum Fenton and Fenton, 1924 is very similar to 7. rectum except that it has abundant and prominent presepiments. The completeness and regular development of the lonsdaleoid dissepimentar- ium in 7. rotundum warrants retention of the separate species name. It is also possible, however, that this is a variant of 7. rectum, with the species thus having a morphotype with abundant, large dissepiments as an adaption for life on soft substrate. Occurrence.—Tabulophyllum rectum occurs in the “Spirifer zone, and Idiostroma zone of the Owen’’, according to Fenton and Fenton (1924, p. 32). T. re- gulare and T. erraticum likewise are found in the “Spirifer zone”, with the former also “‘perhaps in the lower portions of the Owen” (p. 34). My experience is that the species T. rectum does not occur above or below the ‘“‘Spirifer zone” of the upper Cerro Gordo Member. Numerous specimens were collected from various parts of this unit at the following: Type Lime Creek (Locality 28, Appendix), Bird Hill North (Lo- cality 30), Bird Hill (Locality 31), Bird Hill South (Lo- cality 32), and at the Rockford Brick and Tile Com- pany Quarry (Locality 35). Tabulophyllum ehlersi Fenton and Fenton, 1924 Plate 1, figure 10; Plate 7, figures 6—16 Tabulophyllum ehlersi Fenton and Fenton, 1924, p. 34, Pl. 6, figs. 12-16; Smith, 1945, p. 61, PI.3, figs. 9,10. Diagnosis.—Small species of Tabulophyllum char- acterized by elliptical to elongate, compressed trans- verse outline and development of prominent talons. Description.—Small (maximum diameter approach- es 3 cm), oval solitary corals characterized by prom- inent talons and broad, elongate attachment base. Septa are in two orders with minor septa generally only de- veloped as wedge-like ridges on the external wall and 36 BULLETIN 355 on the first heavy presepiment in from the wall. Major septa are amplexoid and may be long, continuous and attenuate; they extend into the tabularium and swirl around an open axis (PI.7, fig.11), or are incomplete and long, extending to axis only on tabulae, but not touching one another. There are 30 to 38 major septa in the eight specimens examined. Maximum diameters range from 24 to 31 mm. The mean number of major septa is 34.8, thus the mean total number of septa for T. ehlersi is nearly 70. Major septa are generally dis- continuous in the lonsdaleoid dissepimentarium, bro- ken by prominent presepiments. In transverse sections, T. ehlersi commonly has a prominent presepiment which rivals the epithecal wall in thickness (PI1.7, figs.10,11). Both commonly have the wavy lamellar (diagenetic) microstructure that is widespread in spec- imens of other species of this genus. In longitudinal section, cut parallel to the axis of elongation, the interior is dominated by long, generally complete tabulae. In the axial region the tabulae form a flat-topped arch and a peripheral trough in the out- ermost tabularium (PI.7, fig.13). Dissepiments are vari- ably developed, at the most forming a dissepimentar- ium with two to four rows of large, steeply inclined dissepiments. It is common, however, to have only one row of very large, nearly vertical dissepiments. Pre- sepiments tend to be more robust than others and are commonly sediment-filled. The presence of a pedestal formed by talons on hard substrates appears in longi- tudinal section as a lateral outgrowth of tabulae and dissepiments, with growth preferentially along the long axis of the elliptical corallite (P1.7, figs 15,16). Amplexoid septa are fixed at their base to the top of flat, complete tabulae. Type Specimens.—Holotype UMMP 7815; para- types UMMP 7816-7821. Discussion.—Tabulophyllum ehlersi has not been reported from any area other than Iowa, nor are other elliptical species of Tabulophyllum known anywhere, with the exception of the large Tabulophyllum ellip- ticum (Hall and Whitfield, 1873, p. 233) from the Lime Creek Formation. In their study of the Lime Creek fauna, Fenton and Fenton undoubtedly relied too much on external mor- phology of the corals. The development of an ovate form is seen in some life stages of T. rectum, and may approach the cross-section dimensions of T. ehlersi. In the latter, the shape is consistent and warrants retaining the species name. No small species of the genus have been reported from Frasnian strata elsewhere (or of other ages) with a consistent elliptical cross sectional outline, as here developed in T. ehlersi. Occurrence.—Specimens of T. ehlersi were collect- ed from the upper part of the “Spirifer zone” of the Cerro Gordo Member at the following localities: South Portland (Locality 27), Type Lime Creek (Locality 28), Bird Hill (Locality 31), Bird Hill South (Locality 32), Juniper Hill (Locality 34) and the Rockford Brick and Tile Company Quarry (Locality 35). Fenton and Fenton also stated that it occurs in the lower part of the Owen Member (1924, p. 35). I have not seen spec- imens from the Owen, either in the field or in museum collections and I assume that the report is erroneous. Tabulophyllum rotundum Fenton and Fenton, 1924 Plate 8, figures 1-16; Plate 9, figures 1—3 Tabulophyllum rotundum Fenton and Fenton, 1924, p. 35, Pl. 2, figs. 5-10; Sorauf, 1989, p. 402, Pl. 1, figs. 5-8, 13-16. Tabulophyllum sylvaticum Rohart, 1988, p. 244, PI.29, figs. 4,5. not Tabulophyllum rotundum Spassky, 1960, p. 26, Pl. 1, figs. 3.4, Pl 2, figss l—6; (Pla3eifigs. li2 Diagnosis.—Small- to medium-sized, ceratoid to trochoid Tabulophyllum with continuous and volumet- rically important lonsdaleoid dissepimentarium. Radi- ally arranged amplexoid, attenuate septa reach into ta- bularium, with flat, generally complete tabulae and prominent, widely-flaring presepiments. Description.—T. rotundum comprises small to me- dium corals with diameters of from 15 to 20 mm, and lengths of from 30 to 50 mm, with the more elongate ceratoid forms approaching 50 mm, the maximum length. Shorter, trochoid corals generally flare some- what in the calicinal end, with a deep and flat-bot- tomed calice. Diameter in mature part of corallites ranges from 19 to 23 mm in seven specimens studied (mean of 21 mm). Radial, amplexoid septa are in two orders, with 30 to 35 major septa generally long and attenuate; they invariably reach into the tabularium, and sometimes extend discontinuously to the axis of the coral. Most commonly, an open space is left at the axis. The lonsdaleoid dissepimentarium is always a prominent part of corallite in this species, with the outer portion of the dissepimentarium characterized by large and heavy presepiments, each of which func- tioned as a wall, barring sediment from the central portion of the coral and bearing both major and short minor septa (PI.8, figs.3,10,12). Longitudinal sections are characterized by complete tabulae that are adorally arched with a flat top in the axial portion of the coral and with a peripheral trough around the outer tabularium (PI1.8, figs.1,4). Amplexoid septa have their bases rooted on tabulae. Occasional tabulae reach very great size and are continuous into the dissepimentarium (PI1.8, fig.6). Dissepiments are elongate and tilted steeply adaxially (PI.8, fig.3), re- flecting the configuration of the steep-sided calice. Pre- sepiments are prominent, sometimes thickened, but in some corals can be very thin and outspread (PI1.9, DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 37 fig.2), apparently providing support for the coral on or in surrounding soft sediment. The dissepimentarium expands and contracts, with one to three or four rows of large dissepiments. Type Specimens.—Holotype, UMMP 7838 (2 new thin sections, PI.8, figs.1,2), paratypes FMNH 26004, 26005. Discussion.—Tabulophyllum rotundum is morpho- logically very similar to 7. rectum, but is differentiated by the nature of the lonsdaleoid dissepimentarium. As- sociated with this is a flaring of the corallite near the calice, which is largely the result of an increase in dissepimentarium size. The presepiments in some in- dividuals form very large, thin sheets over adjacent sediment, and would have been effective in distribut- ing the weight of the coral over a large area. If this feature is an adaptation to substrate, then 7. rotundum may be an ecophenotype of 7. rectum, adapted for life on fine, soft sediment. It is treated here as a separate species because its paleoecology is not well known. Tabulophyllum rotundum Spassky (1960, p. 26) from the Middle Devonian of the Altai Region of the Russia is a junior homonym; the name of this taxon was changed by him to T. manifestum Spassky (1971, p. 106). Tabulophyllum sylvaticum Rohart (1988, p. 244) very closely resembles 7. rotundum, and should be synonymized with it. Especially the photographs of the holotype and paratype specimens (Rohart, 1988, pl. 29, figs 4,5) are very close to the paratype of 7. ro- tundum illustrated here in figure 3 of Plate 8. Occurrence.—In Iowa, Tabulophyllum rotundum only occurs in the upper Cerro Gordo. The holotype was collected from these beds at Bird Hill (Locality 31, Appendix); the two paratypes came from the Type Lime Creek (Locality 28). I collected specimens from Bird Hill and from Bird Hill North (Locality 30). The species is also known from the Frasnian Ferques Lime- stone of the Boulonnais region of France. Tabulophyllum ellipticum (Hall and Whitfield, 1873) Plate 9, figures 4—9 Chonophyllum ellipticum Hall and Whitfield, 1873, p. 233, Pl. 9, fig. 13; Fenton and Fenton, 1924, p. 29, Pl. 3, figs. 5-8. Diagnosis.—Medium-large elongate ovoid species of the genus, having a broad, short corallum with a wide elongate base, 90 to 94 septa, poorly developed minor septa commonly discontinuous or with wedge- shaped form adjacent to thick presepimental walls. Dissepimentarium narrow relative to tabularium, filled with abundant presepiments. Tabulae complete at sev- eral levels. Description.—The two specimens available for study are the neotype (P1.9, figs.4—7), and one slightly crushed specimen collected from upper Cerro Gordo beds (PI1.9, figs.8,9). The neotype is elliptical in out- line, with a long axis of 34 mm and a minimum of 19 mm, while the other is 46 to 50 mm maximum and 25 to 26 mm minimum (with variation between two trans- verse sections). In transverse, both specimens show numerous dilated, spear-shaped major septa that are thick in the dissepimentarium and very thin in the ta- bularium. Septa are long and extend nearly to the axial plane of the coral. Septa are numerous, with a total of 94 septa in the neotype in which minor septa only reach to the innermost dissepimentarium, and 89 (that can be counted) in the other, partially recrystallized specimen. In the latter, minor septa are discontinuous (P1.9, fig.8), but still have heavy, wedge-shaped bases on presepiments, and both major and minor septa have wedge-shaped bases on the outer wall of the coral. The transverse view is dominated by the heavy bases of septa against walls and presepiments with heavy ster- eome on the latter. Septa thus are somewhat dilated, uncommon for Tabulophyllum species in the Cerro Gordo. In longitudinal view corals are short and broad with a very wide tabularium shown in the long axis view (P1.9, fig.5), and with tabulae complete where not in- terrupted by axial ends of the septa, but commonly showing disruption. As typical for the genus, a pe- ripheral trough is present at the margin of the tabular- ium. The dissepimentarium has dissepiments and pre- sepiments of various sizes, and major change in di- ameter of the coral is accomplished by rapid changes, both in width of dissepiments and in size of elongate, inclined presepiments. In longitudinal sections septal structure is very fine- ly trabeculate, with trabeculae inclined adaxially, as is general in the genus (PI1.9, fig.6). Type Specimen.—Neotype, USNM 78624 (speci- men figured by Fenton and Fenton, 1924, PI.3, figs. 7,8, noted as ““C.L.W.”’, from the Webster collection. Discussion.—The species was established by Hall and Whitfield in 1873, who noted it (Chonophyllum ellipticum) as “Coral small, subturbinate, laterally compressed, and much distorted in growth;”. This de- scription leads one to wonder whether they were in- cluding smaller forms in Chonophyllum ellipticum that are regarded here as Tabulophyllum ehlersi, along with the larger specimens included by Fenton and Fenton in the former (1924, p. 20). The Hall and Whitfield holotype has been lost. Of the two or three specimens figured by Fenton and Fenton (Plate 3, figures 5—8) only one has survived, that of figures 7 and 8, which was in the Webster collection and is now USNM 38 BULLETIN 355 78624. I designate this specimen as neotype, as it is the only available specimen that was placed in this species by Fenton and Fenton. The lost Hall and Whit- field holotype was collected ‘‘in the marly beds at Rockford, Iowa’ (1873, p. 233), which indicates the Cerro Gordo Member of the Lime Creek Formation. The Webster specimen (neotype) comes from Hack- berry Grove, and also originated in the Cerro Gordo. The specimen collected by me at Locality 27, South Portland, is from high in the Cerro Gordo, in shales with abundant solitary corals occurring 4 to 5 m above the ‘“‘rusty-weathering bed’’. T. ellipticum is the only large species of the genus with an elongate oval outline, as seen here. Occurrence.—The two specimens described here are from the upper part of the Cerro Gordo Member of the Lime Creek Formation. That noted by Hall and Whitfield likewise came from Cerro Gordo beds at Rockford. Except for the single specimen of Tabulo- phyllum ponderosum, these specimens of 7. ellipticum are the largest solitary corals found in the Cerro Gordo beds. Tabulophyllum ponderosum Fenton and Fenton, 1924 Plate 10, figures 1,2 Tabulophyllum ponderosum Fenton and Fenton, 1924, p.40, Pl. 4, figs. 4,5, Pl. 5, figs. 5,6. Diagnosis.—Very large solitary coral with wide dis- sepimentarium; both major and minor septa withdrawn from periphery. Major septa numerous, heavy, extend half way through tabularium. Dissepiments and pre- sepiments numerous and varied, tabulae sparse and complete, flat to downbowed. Description.—The single representative of the spe- cies is a very large corallite, 66 mm in maximum di- ameter; eroded on one side. The configuration of the eroded side marks this specimen as the paratype illus- trated by Fenton and Fenton (their pl. 5, fig. 6); thus it is chosen as neotype. Its large size is very unusual among Cerro Gordo corals. The species is unique, with its large size and wide, very well-developed outer dissepimentarium formed of varied presepiments interspersed with what seem to be normal dissepiments. Septa are numerous, with 60 major septa present in the one specimen, and presum- ably an equal number of minor septa, some of which have been eroded away. Fenton and Fenton recorded a range of 110 to 140 septa in the species, including the two lost specimens. Septa are restricted to the inner dissepimentarium and the tabularium. Major septa ex- tend approximately “ of the way to the axis, and are dilated within the tabularium. The stereome coating major septa in the tabularium also coats the innermost dissepiments to form a zone of heavily dilated skeleton in the inner /, of the coral. Some bilaterality is also present in this specimen, with major septa arranged pinnately around a shortened major septum, apparently the cardinal septum. In longitudinal section, tabulae are flat, rather wide- ly spaced and complete. At intervals these flat, com- plete tabulae are thickened by stereome (PI.10, fig.2). There are well-developed peripheral gutters surround- ing the tabularium in this specimen, as in other large species of the genus. The dissepimentarium is broad and contains numerous dissepiments. On one side of this specimen (concave side), the dissepimentarium is narrower and composed of sloping rows of uniformly sized, normal dissepiments with some larger elongate, flattened dissepiments (or presepiments) interspersed. On the opposite side of the corallite, the dissepimen- tarlum is much broader, rows of dissepiments are more irregular and the sizes and shapes of dissepiments and presepiments are much more variable and somewhat more bulbous as well. Type Specimen.—Of the holotype and two paratypes figured by Fenton and Fenton (pl. 4, figs. 4,5; pl. 5, figs. 5,6), only the paratype illustrated in their plate 5, figure 6 has been located (USNM 78623). The speci- men is here chosen as neotype, as it is apparently the only specimen available for study. Discussion.—T. ponderosum is as large as the larg- est species of the overlying Owen Member of the Lime Creek Formation, but is unique in the development of its extremely broad dissepimentarium and very large number of relatively small dissepiments within. T. ponderosum of Iowa has characters in common with the late Frasnian species 7. zonatum, reported from the Contadero Formation of New Mexico by So- rauf (1988, p. 160). 7. zonatum is characterized by a short cardinal septum, dilation of septa in the two car- dinal quadrants, an open area at the corallite axis, and numerous modestly sized dissepiments and presepi- ments, as is 7. ponderosum. However, the very large size (66 mm diameter) and very large number of septa (total up to 140 major and minor) places 7. pondero- sum outside the range of variation seen in 7. zonatum. Tabulophyllum mcconnelli from Frasnian strata in northwestern Canada is also a large species of the ge- nus. It is not as large as 7. ponderosum (50 mm max- imum diameter vs. 65 mm in the latter), does not have as many septa (approximately 100 total septa vs. 120 in the latter), and has less bilaterality than does 7. pon- derosum. Occurrence.—The neotype is labeled as coming from Hackberry Grove, Iowa, which would indicate that it was collected within the Cerro Gordo Member DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 39 of the Lime Creek Formation. Fenton and Fenton stat- ed that it occurs in the middle and upper part of the “Spirifer zone’, which is the upper part of the mem- ber. Tabulophyllum robustum Fenton and Fenton, 1924 Plate 10, figures 3-10 Tabulophyllum robustum Fenton and Fenton, 1924, p. 37, Pl. 5, figs. 1-3. Tabulophyllum exiguum Fenton and Fenton, 1924, p. 37, Pl. 3, fig. 9. Diagnosis.—Medium-sized corals with subturbinate to subcylindrical shape, large number of septa extend- ing into tabularium. Corallite round, with generally narrow dissepimentarium and steeply inclined, elon- gate dissepiments. Tabularium broad with complete, flat-topped tabulae and peripheral gutters. Description.—The five specimens placed with cer- tainty into this species are medium sized, but large for the Cerro Gordo, with the holotype measuring 32 mm in diameter, the paratype 31 mm, and 22 mm for the holotype of 7. exiguum, which is eroded and lacks part of the dissepimentarium. In each, the tabularium is from 11 to 18 mm in diameter in transverse section. Major septa vary from 39 to 48, with the total number of minor septa difficult to ascertain due to the state of preservation of these corals. Major septa are thin to dilated in the periphery, reaching several millimeters in thickness in the holotype (Pl. 10, fig.3), while re- maining thin (less than 1 mm) in the other specimens. Septa are amplexoid, and may reach the axis of the corallite, but more often leave an open space in the axial region. Minor septa are thin and very discontin- uous. In the holotype, minor septa are developed as short wedges at the outer wall (P1.10, fig.3), but only as short spines on presepiments at the inner margin of the variably wide dissepimentarium (P1.10, figs.5,7). Longitudinal sections of T. robustum are character- ized by a wide tabularium with complete and _flat- topped tabulae, along with the peripheral gutter com- mon in species of this genus (PI1.10, figs.4,6). The ho- lotype exhibits a broad attachment base, but the base of the paratype is broken. Some specimens do not have a broad base of attachment, but instead a more pointed apical end. The dissepimentarium of the holotype is narrow and formed of steeply inclined rows of elon- gate dissepiments (PI.10, fig.4). In the paratype, one side of the specimen has a greatly expanded dissepi- mentarium formed of large presepiments that are ir- regularly shaped as seen in transverse section (P1.10, fig.6), and are greatly elongate and inclined. They may occupy the entire dissepimentarium. On this one side of the paratype, septa are pulled away from the outer wall, presumably as the coral expanded its exterior dis- sepimentarium, apparently to avoid sinking into soft substrate. Type Specimens.—Holotype USNM 78632A, para- type USNM 78632. Tabulophyllum exiguum holotype FMNH 26007. Discussion.—Tabulophyllum robustum was estab- lished by Fenton and Fenton on the basis of two spec- imens in the Webster collection. I have also included Tabulophyllum exiguum in the species (PI1.10, figs.9,10). T. exiguum is a species based on a single specimen and no transverse section was made by the Fentons. They noted that it was characterized by an axial boss in the calice, but in transverse section, septa do not always reach to the axis of the corallite, as in other species of the genus with long septa. In this sec- tion, the holotype of 7. exiguum strongly resembles T. robustum, where amplexoid septa do not generally reach the axis of the corallite. The two species are similar in size and number of septa. I thus regard T. exiguum as synonymous with T. robustum. Two ad- ditional specimens are also placed in the species. Of the specimens of 7. mcconnelli figured by Smith (1945, pls. 2,3), several would appear to conspecific with 7. robustum. At present it is not possible to ac- curately determine exactly which are conspecific, and whether 7. mcconnelli should be synonymized with T. robustum. This awaits restudy of the 7. mcconnelli fauna from the Hay River area of western Canada. Occurrence.—The three museum specimens are la- beled as collected from the “‘Spirifer zone’ at Hack- berry Grove, Iowa, thus the species occurs in the upper portion of the Cerro Gordo Member at the type section (Locality 28, Appendix). Two additional specimens collected by Calvin Levorson were from stripped ma- terial of the upper Cerro Gordo Member at the Rock- ford Brick and Tile Company Quarry (Locality 35). Tabulophyllum longum Fenton and Fenton, 1924 Plate 11, figures 1-6; Plate 12, figures 1—5; Plate 13, figure | Tabulophyllum longum Fenton and Fenton, 1924, p. 39, Pl. 3, fig. 1: Sorauf and Pedder, 1986, p. 1267, fig. 3; Sorauf, 1989, p. 401, P1.4, figs. 1,2. Diagnosis.—Species of the genus with 80—110 sep- ta in adults and diameter up to 55 mm. Septa non- dilated, attenuate and long in adult corallites, with sep- ta generally joined at axis, or with small axial open space. Tabularium broad with tabulae commonly flat and complete; dissepimentarium generally narrow with steeply inclined dissepiments and with lonsdaleoid dis- sepimentarium well-developed marginally. Description.—Tabulophyllum longum is a medium large species, and the most abundant solitary coral of the Owen. In 27 post-juvenile (relatively mature) in- 40 BULLETIN 355 Total number of Septa re) oO t \ \ \ 1 holotype 90+----- = -- fa --4-=----1 - ff ---4------ ==sse= F==--- : 80+----- z---mm----- Ne ea - et ees fea s 70+----- 4------ q----== a ls a r----- | Tabulophyllum longum | 604 t - t + 1 ' 10 20 30 40 50 60 70 80 90 Corallite diameter in mm Text-figure 31.—The large diameter corals from the Owen Mem- ber, Tabulophyllum longum, Tabulophyllum magnum, and Tabulo- phyllum expansum, with corallite diameter (in mm) plotted versus the total number of septa in each corallite. The holotypes of 7. lon- gum and T. magnum are identified. The holotype of T. expansum is the larger individual of the two plotted. The reason for overlapping in size between species is that immature specimens of 7. magnum have a small enough diameter to fall within the field of 7. longum. dividuals, the range in corallite diameters is from 21 to 55 mm. The same corals have a range of from 39 to 52 major septa (Text-fig. 31). In the nine individuals in this sample that have 40 major septa or more, the mean diameter is 39 mm with a mean number of major septa of 54. These are representative of mature indi- viduals in this species. Tabulophyllum longum is a trochoid coral which may approach 70 mm in length, although this is not seen often, due to decortication of large specimens. In weathered-out specimens the calice displays a flat-bot- tomed calicinal pit approximately 20 mm in diameter and 13 mm deep, with development of a slight boss shown in a transverse section slightly below the calice, and with a narrow shelf surrounding the tabularial pit. In transverse thin section the specimens commonly lack the epithecal wall (Pl.11, figs.1,3,4) present in un- abraded individuals. Septa are numerous, and clearly differentiated into major and minor septa. Major septa are attenuate and extend to the axis of the corallite with only minor deflection at the axis. Septa are straight and long, with variable minor septa. These may be up to ¥, the length of major septa or much shorter, as little as /; the length of major septa. When well-developed they generally extend into the outer dissepimentarium. The cardinal septum is slightly shorter than other major septa and may be in a shallow fossula (P1I.12, figs.4,5). In the holotype, the cardinal septum is characterized by a lumpy, straight-sided di- lation at the boundary between the tabularium and the dissepimentarium (PI.11, fig.1), although this is not characteristic of most individuals. In the tabularium, tabular Segments appear as straight skeletal elements between equally straight septa. Dissepiments are straight to arcuate in the outer part of the corallite, and there are heavy rows of presepiments, forming inner walls. Presepiments do not disrupt major septa except right at the periphery of adult corals, although minor septa are interrupted around much of the periphery. The area of presepiments apparently was easily abrad- ed and has been partly or mostly removed in many individuals. Large presepiments are not shown in the holotype except right at the periphery, although this is variable in large individuals. The species characteris- tically has a relatively narrow dissepimentarium. Septal microstructure seen in transverse section is clearly of very fine monacanth trabeculae, which form a line of dark spots in the axial plane of septa, with flanks of fibro-normal calcite. Dissepiments, and in particular thickened presepiments, commonly have a lamellar to wavy-lamellar structure that is diagenetic in origin. A septotheca is seen in some individuals of this species. In longitudinal section, 7. /Jongum shows features that would be generally expected in large species of Tabulophyllum; namely 1) tabulae interrupted in the axial area by long septa, while the outer tabularium is characterized (Pl.11, figs.2,5) by downbent tabulae forming “‘gutters’’, and 2) a dissepimentarium formed of several rows of relatively large, steeply inclined dis- sepiments, and which is narrow as compared to that of other large Iowa species of the genus (PIl.11, fig.5; Pl.12, fig.1). In 7. longum, the dissepimentarium is generally composed of less than six or seven rows of dissepiments. It may be confused in transverse section with the outer tabularium, where incomplete tabulae are intersected by the plane of the section. The tabularium is broad, varying in longitudinal section from 24 to 26 mm, filled with rather evenly spaced tabulae characteristically forming marginal troughs, with a smooth curve up to an elevated central area (PI.11, fig.5). Amplexoid septa are interrupted at intervals, but only in the corallite axis. For the most part, septa interrupt tabulae throughout most of the ta- bularium. The dissepimentarium comprises an arcuate series of vertically compressed ovate dissepiments with up- wards of seven dissepiments per row, with each row steeply inclined (in excess of 75°) next to the tabular- ium, becoming progressively less inclined outward. The size of dissepiments varies, with larger dissepi- ments randomly distributed. No large presepiments are preserved in this section of the holotype or topotypes, in part at least, because the peripheral part of the corals has been removed by erosion. The dissepimentarium DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 41 is characteristically narrow, and is commonly lacking in juveniles. In each row, there may be as few as three to five steeply inclined dissepiments which tend to par- allel the outer wall and thus cause the elongate coral shape. Septal microstructure seen in longitudinal view is composed of very fine monacanth trabeculae arranged in an arcuate manner, perpendicular to the arch of dis- sepimental rows, and increasing axially in inclination (P1.12, fig.3). The wall is a septotheca, formed by the expansion of peripheral portions of both major and minor septa. In sections of juvenile corals, septa are dilated and invariably swirl around the corallite axis with no dis- cernable cardinal-counter plane. Dissepimentaria are generally lacking and commonly only one row of pre- sepiments appeared as the coral matured. Type Specimens.—Holotype FMNH 26011, para- types, USNM 78634 and 78634A. Discussion.—This is the most abundant solitary species in the Owen Member. Numerous individuals have been collected from the southerly part of the study area, where the Owen was actively quarried. Young individuals with diameters of less than 1.5 cm are almost evenly divided between forms that have short, straight septa and others that have longer septa that swirl at the axis of the tabularium. These can lack a dissepimentarium or develop one which has two rows of dissepiments at most. Development of the cardinal septum is somewhat variable. Many of the juvenile corals have recogniza- ble bilaterality with a differentiated cardinal septum; these are forms with long septa. It is common in this species that the cardinal septum is short, with some bilaterality to the arrangement of septa, especially in the cardinal quadrants. Small individuals with short septa tend to lack bilaterality. Adults are most gener- ally characterized by a short cardinal septum and/or a long counter septum and accompanying bilaterality. Figures 4 and 5 of Plate 12 illustrate in part, the vari- able nature of adults of this species in the length of their cardinal septum and development of symmetry. In longitudinal section, where septa are amplexoid at the axis of the corallite, an arched irregular structure is present axially in 7. Jongum. Seen in transverse sec- tions of the holotype (PI.11, fig.1), this structure is formed by arching of a tabula interrupting septa, which are then based on the tabula. Axially to this amplexoid base, septa have a very irregular path, and are variable in length and thickness. That the structure is irregularly developed in the species can be seen in some trans- verse sections, as well as the longitudinal section of the holotype. This forms an axial boss in the calicinal pit of the mature corallite. Tabulophyllum longum is typical of large species of the genus, and thus resembles other large species; not only those found in the Owen Member of the Lime Creek, but in other Frasnian outcrop areas. It resem- bles in size the large species Tabulophyllum zonatum from Frasnian rocks of New Mexico, but differs from this species by the strong bilaterality and shorter septa of T. zonatum. It also can be compared to Tabulo- phyllum smithi Tsien, reported by Rohart from the Boulonnais region of France (1988, p. 242) and from the Ardennes of Belgium by Coen-Aubert (1982, p. 38), but the latter is characterized by large presepi- ments around the corallite periphery. These are not seen in 7. longum. Some corals assigned to Tabulo- phyllum mcconnelli from the Hay River area of west- ern Canada by Smith (1945, p. 59) may well belong in the Iowa species, but such a decision awaits restudy of the western Canadian fauna. Other large species of the genus are known, but their pronounced bilaterality makes them distinct from this Iowa species. Occurrence.—Fenton and Fenton (1924, p. 39) stat- ed that T. Jongum is found in the Owen, particularly in what they referred to as the ““Acervularia zone’, the uppermost beds of the member. Individuals of Ta- bulophyllum longum occur in the uppermost beds of the Owen at the Lillibridge Quarry (Locality 38, Ap- pendix), the Buseman Quarry, south of Dumont, Iowa (Locality 40), the North Buseman Quarry (Locality 40A) and, also from the uppermost beds of the mem- ber at the Carrolus Quarry (Locality 41, Appendix). Tabulophyllum magnum Fenton and Fenton, 1924 Plate 13, figures 2—7; Plate 14, figures 1-5; Plate 15, figure | Tabulophyllum magnum Fenton and Fenton, 1924, p. 38, Pl. 3, fig. 2, Pl. 4, figs. 1-3; Sorauf, 1989, p. 401, Pl. 2, figs. 2—5, PI.3, fig. 3, Pl.4, fig. 4. not Tabulophyllum magnum, Tsien, 1976, p. 267, Pl. 2, fig. 3. Diagnosis.—Large species of genus, with diameters up to 75 mm, and total of 100 to 128 long septa that join at the axis or swirl to form axial boss. Dissepi- mentarium wide with prominent marginal presepi- ments; dissepiments and septa dilated in inner disse- pimentarium to form solid or semi-solid rings around tabularium. Tabulae generally incomplete. Description.—Ten specimens assigned to T. mag- num are large, ranging in diameter from 34 to 72 mm with a mean of 56 mm. Of these, seven more or less adult individuals range from 60 to 72 mm, with a mean diameter of 60 mm (Text-fig. 31). The number of ma- jor septa in these seven corals ranges from 47 to 58 with a mean of 54. The total range in number of major septa in the ten individuals is from 44 to 58, with a mean of 51.5. 42 BULLETIN 355 The species is large, with an oval outline. The di- ameter of the tabularium is large, but generally is not more than /, to Y, of the total diameter, with a large and prominent dissepimentarium occupying the rest of the corallite (P1.13, figs.2,5). There are a large number of septa, equally divided into major and minor septa. The septa are long, and the cardinal and counter septa are commonly differentiated from the rest, especially the cardinal. Septa in the cardinal quadrant may also be arranged pinnately to the cardinal septum. Minor septa are well developed and commonly are more than 7, the length of the long major septa. Septal dilation is prominent in the inner dissepimentarium. In transverse section the dissepimentarium appears filled with numerous dissepiments similar to herring- bone dissepiments (Hill, 1981, p.F24). Both septa and dissepiments are thickened in the inner dissepimentar- ium and outer tabularium (PI.13, figs.2,3). Septal di- lation also occurs here, and two to three rows of prom- inent, thick, steeply inclined dissepiments occur at this junction. Most septa join at the axis and there is a recognizable axial structure, although no raised boss is seen in the calicinal pit of the holotype. The development of presepiments is not widespread, and generally only interrupts one major septum (PI.13, fig.5). Presepiments are rare in the holotype, although this is perhaps at least partially due to corrosion and decortication during weathering; thus an outer, perhaps more lonsdaleoid dissepimentarium may be missing. No epitheca is visible. In other specimens of the spe- cies (PI.14, fig.2), the occurrence of presepiments is more common in the outer dissepimentarium than in the holotype. Here too, presepiments seldom interrupt major septa although all septa are discontinuous near the periphery of the corallite. In longitudinal section, the broad, arcuate dissepi- mentarium is prominent, with dissepiments of various sizes seen forming rows with numerous small flattened forms with interspersed larger, more bulbous dissepi- ments (P1.13, figs.3,4,6). These rows reflect the shape of an arched calicinal platform. The innermost part of the dissepimentarium is marked by presence of abun- dant stereome. Here steeply inclined innermost dissep- iments are thickened to form rows prominent in trans- verse section. The tabularium is complicated by the presence of numerous long septa, so that virtually no complete ta- bulae are seen. Lateral gutters typical of the genus are developed (PI.14, fig.1), and there is a flat-topped, arched aspect to the tabularium at the axis. Septal structure seen in longitudinal section is com- posed of thin, monacanth trabeculae which arch over and in towards the tabularium (PI1.15, fig.1), and cen- trally are oriented parallel to the axis. Septa are rec- ognizably amplexoid when seen in longitudinal view, with heavy trabecular bases developed across the tops of tabulae (P1.14, fig.1). Juvenile stages of the species are characterized by inflated septa that swirl around the corallite axis. At a slightly more advanced stage (PI.13., fig.7), corallites tend to have long septa joined at the axis and display bilaterality due to the elongation of cardinal and/or counter septa across the axis and a somewhat pinnate arrangement of the septa. Type Specimens.—Holotype FMNH 26009, para- type USNM 78633. Discussion.—T. magnum has been identified from Belanski and Webster collections, all of which origi- nated from a since disappeared collecting locality /, mile upstream from the Claybanks on the Winnebago River (Locality 28, Appendix). Among the complex of small Tabulophyllum col- lected at the southerly localities (Localities 39, 40, 41, Appendix) are a number of individuals that could be young 7. magnum, but only one was assigned with certainty to this species because of its elongate, pinnate bilateral nature which strongly resembles sections through youthful parts of large, mature 7. magnum from farther north, near the Winnebago River. The largest specimen of Tabulophyllum magnum seen in this study (PI.14, figs.2,3) was collected from upper Owen beds at the Lillibridge Quarry (Locality 38, Appendix). The outline of the coral is rounded, with a diameter of 70 mm, and 56 major septa present. The major septa are long, and swirl around at the cor- allite axis so that there is no open space. The specimen was collected from rock matrix, rather than weathered out, thus the outer dissepimentarium is well preserved and adds much information regarding its morphology. Dissepiments are thickened by stereome in the inner- most dissepimentarium, as common in this species, are very numerous and are uniformly arched away from the corallite axis (PI.14, fig.3), sometimes sharply, sometimes smoothly arched. Where presepiments are developed, they are large and are elongate at the pe- riphery. Both major and minor septa are interrupted by the well-developed presepiments in the outer dissepi- mentarium. The longitudinal section of this large specimen shows the leaf-like expansion of both presepiments and dissepiments. It appears that many dissepiments formed on the presepiments that were covering sedi- ment lateral to the main coral. The dissepiments are extremely low and flat at the periphery and these low, flattened forms are steeply dipping at the margin of the tabularium. Tabulae are generally complete, and are flat or sagging between septa in the axial region. Nine or more large open spaces are seen in the tabu- DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 43 larium in longitudinal section. It is not clear what the relationship is between these tabularial “‘gaps”’ and ex- panding and contracting of the corallite diameter, as shown by the leaf-like expansions of the dissepimen- tarium (PI.14, fig.3). It is clear that the entire corallite was affected by environmental changes, most probably connected to rate of sedimentation. Other large, bilateral species of the genus are known, and resemble Tabulophyllum magnum. One of these is Tabulophyllum zonatum from the late Frasnian Contadero Formation of south-central New Mexico. However, 7. magnum, with its long septa, spear-like septal dilation in the tabularium, and lack of large pre- sepiments in its periphery, does not resemble the New Mexico form other than superficially. The only other species that closely resembles 7. magnum is T. expan- sum, which is undoubtedly very closely related, and possibly conspecific. Occurrence.—Fenton and Fenton (1924, p. 38) not- ed that the occurrence of 7. magnum is in the Owen Member, and “generally found in detritus’’. I found no specimens of the species in the northern outcrop area, but assume from the area where these were collected that they derived from the upper part of the Owen, the so-called ““Acervularia zone” of Fenton (1919). In my collecting of Owen Member corals, most of 7. mag- num came from the uppermost beds of the member. The one largest individual was collected from the Lil- libridge Quarry (Locality 38), and others at Buseman Quarry (Locality 40) and Carrolus Quarry (Locality 41). Tabulophyllum expansum Fenton and Fenton, 1924 Plate 15, figures 2—6 Tabulophyllum expansum Fenton and Fenton, 1924, p. 39, PI. 2, figs. 2: Diagnosis.—Species defined originally on external form, which is short and broad. Species has very large diameter and long septa which swirl around axis to form columellar boss. Description.—Two specimens are placed in this spe- cies, the holotype and one other, less mature individual (Text-fig. 31; Pl.15, figs.2-6). The holotype is weath- ered, with epitheca removed, as typical for material from this locality (west of Type Lime Creek). No signs are seen of talons or base, as in the 7. magnum ho- lotype. A calicinal pit is present, 2 to 3 mm deep with a very slightly raised axial boss. Septa are long, and swirl to form a very low, arching boss approximately 10-20 mm high. The calicinal platform is not flat, but upwardly rounded, with its maximum elevation 7, of the way in towards the boundary of the calicinal pit. Weathering of this specimen may have exaggerated the configuration of the upper surface. The species is oval in outline, with the outer diameter varying from 72 to 56 mm, and the oval tabularium having a maximum diameter of 43 and a minimum of 33 mm. Septa total 128 in the holotype, with clear differentiation into ma- jor and minor series. In transverse section, the axial area of the corallite is dominated by long septa that swirl counter-clockwise. Swirling septa are joined lat- erally by stereome to form a solid structure (PI.15, figs.2,5). Septa are notably amplexoid, even at the axis, where a tabula forms a base beneath the swirled septal mass (PI1.15, fig.5). In the outer tabularium and innermost dissepimentarium septa are dilated, as in T. magnum. Together with one or two rows of heavy, dilated dissepiments, they form a heavy ring around the tabularium. The outer dissepimentarium is similar to that in 7. magnum in that dissepiments are irregular, and presepiments occur rarely or not at all. This spec- imen was also decorticated during weathering. In longitudinal section, the tabularium is flat but arches near the axis, with some complete tabulae and others that are low and vesicular. The amplexoid na- ture of septa is evident here (PI.15, figs.3,4), more so than in 7. magnum, although the shallow gutter seen in the periphery of the tabularium here is not as marked as in T. magnum. Dissepiments are varied in size with some large ones more typical in size and shape to those presepiments seen elsewhere in the ge- nus. Dissepiments here form arcuate rows, steeply in- clined at the innermost dissepimentarium and flaring outward to the periphery of the corallite. Most interior dissepiments are thickened where steeply inclined. Fine monacanth septal trabeculae are perpendicular to the rows of dissepiments, and thus incline progres- sively inward within the dissepimentarium, but are nearly parallel to the corallite axis in the tabularium, with a noticeable elbow at the boundary between the two areas. Type Specimen.—Holotype, only specimen thus as- signed by Fenton and Fenton, FMNH 26012. The only known topotype is SUI 3339. Discussion.—This species is very closely related to T. magnum, and could be placed within the latter as a subspecies or ecovariant. It is characterized by a very large number of septa, in the neighborhood of 128 in total, while 7. magnum generally has 20 fewer, even in mature individuals. 7. expansum has a pronounced axial boss in addition to its extremely wide, flaring dissepimentarium. While the latter may reflect adap- tation to soft substrate, the former is seen both in the adult holotype and in the other individual, a less ma- ture form. With the present sample I prefer not to com- bine this species with 7. magnum. Occurrence.—T. expansum is very rare; the speci- 44 BULLETIN 355 € 6 8 6 Number of Septa > Tabulophyllum mutabile T 10 15 20 25 30 35 40 45 Diameter of Corals - mm Text-figure 32.—Tabulophyllum mutabile n. sp. of the Mason City Member, corallite diameter (in mm) plotted versus the number of major septa within each individual. The holotype of this new species is indicated on the graph. mens examined were collected long ago by Webster and Belanski, at a locality noted as 0.5 miles west of the claybanks on the Winnebago River. I was not able to find either an outcrop or specimens at this location, and assume that changes in topography or the course of the river during 75 years have obliterated the col- lecting locality. Tabulophyllum mutabile, new species Plate 1, figure 6; Plate 16, figures 1—9; Plate 17, figures 1-4 Diagnosis.—Medium-sized species of the genus having well-developed presepiments in broad lonsda- leoid dissepimentarium, with no continuous septa therein. Axially, major septa are generally short and thin while minor septa occur as spines only on pre- sepiments. Some individuals have identifiable cardinal plane and are weakly bilateral. Description.—Tabulophyllum mutabile contains generally turbinate corals that flare outward as adults. Corallites are moderately large; for 24 individuals sampled, the total range in diameter is from 13 to 43 mm, but mature individuals vary from slightly less than 30 mm to 43 mm, and from 29 to 43 major septa (Text-fig. 32). Mature corals have a more narrow range, from 39 to 43 major septa. Major septa may be long and reach to the corallite axis and swirl around it, or be long, with a small open space at the axis, or considerably shorter, with an open space of up to 5 mm at the axis (Pl. 16, figs.1,2,6). The perceived length of septa partially depends on the position of the thin section in the corallite, because amplexoid septa are long where they have been sec- tioned in the axial region above a major tabula (PI1.16, figs.3,4), while appearing to be short beneath it. Major septa aré thickest at the exterior wall, and are attenuate inward: they generally maintain a uniform width through the dissepimentarium and then thin into the tabularium. Minor septa are present only as spines, both on the exterior wall, and sometimes on presepi- ments in the outer dissepimentarium. The innermost presepiment has spine-like minor septa between each of the major septa (Pl. 16, figs.2,6). In the outer, lons- daleoid part of the dissepimentarium, both major and minor septa are interrupted. On the external wall are spines of both that are equal in development and ap- pear pyramidal in cross section. In some corals, there is an identifiable cardinal sep- tum, shorter than the others (PI1.16, fig.5; Pl.17, fig.1). Where this septum is short a weak bilaterality is de- veloped and this also occurs in juvenile sections,. Seen in transverse sections, the lonsdaleoid dissepimentar- ium is well developed in this species, presumably in response to rapid or abundant sedimentation. Individ- uals of 7. mutabile may have up to five rows of very well developed presepiments which are large and ir- regular, and may be laterally elongate, up to /, of the total perimeter of the corallite (P1.16, fig.6). Common- ly both major and minor septa are only developed as spines on the presepiments, although major are stouter and longer. In addition, presepiments often have inter- stitial spaces filled with sediment which was perhaps included within the coral skeleton during rapid sedi- mentation. This may have triggered a resulting more rapid upward growth, with the ensuing formation of large presepiments by the polyps. In longitudinal section, tabulae commonly are com- plete and subhorizontal, with wide spacing (as a result of rapid growth?), with both flat, regular tabulae form- ing bases for amplexoid septa and associated less com- plete irregular tabulae. It is common in this species that widely spaced tabulae have intertabular spaces in- filled by sediment, just as presepiments are (PI.16, fig.4; Pl.17, figs.3,4). In some corallites this seems to occur at regular intervals, although more randomly in most. Dissepiments seen in longitudinal section are abun- dant in some corallites, with their long axes inclined towards the corallite axis (PI1.16, fig.7). Presepiments tend to be very large, are peripheral to the dissepi- mentarium, and also are steeply inclined. In some cor- als, presepiments are rather bulbous in appearance in longitudinal section, but very elongate and generally infilled with sediment. The long axes of presepiments are generally parallel to walls of corals and flare when the walls flare. The microstructure of septa is of very fine mona- canth trabeculae in longitudinal section, with septal DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 45 bases expanded to form septotheca (Pl. 16, fig.9). Crystal fibers of septal bases are directed laterally to form the wall. Sections of juvenile corals are characterized by short septa that are stout and tend to swirl somewhat around an open axial area. A lonsdaleoid dissepimentarium is seen, even in young specimens, but involves a single row of presepiments in these juvenile growth stages. Type Specimens.—Holotype SUI 2247; paratypes SUI 1731, 141, 431, and 84745. Discussion.—This is a highly variable species, but apparently one which was able to build skeleton rap- idly, resulting in elongate corallites with wide lons- daleoid dissepimentaria. Perhaps this was a response to rapid sedimentation. One of the striking aspects of the species is the wide spacing of tabulae and common infilling of intertabular spaces with sediment. This is also a species that was commonly bored by an un- known organism. Since no repair of holes was noted, the borings apparently were made after the skeleton was vacated by coral polyps. Boring is widespread in corallites of 7. mutabile, but was not noted in any other species of Shell Rock corals. Tabulophyllum mutabile cannot to be confused with any of the Lime Creek species. Small diameter Lime Creek species (such as T. rectum, T. rotundum) are all notably smaller than this abundant species of the Shell Rock Formation, while the larger species of the Lime Creek generally have characteristic septal dilation, bi- laterality, and small presepiments, thus easily distin- guished from the somewhat smaller 7. mutabile with its very broad and large presepiments and general lack of septal dilation. T. mutabile resembles the Frasnian species 7. ovin- um from the Sly Gap Formation of New Mexico (So- rauf, 1988, p. 163). The New Mexico species is about the same size as expressed by diameter, and number of septa as a medium-sized individual of the Iowa fau- na. Both species have nearly radial septa and complete tabulae, but 7. mutabile lacks the thick wall, broad septal bases, and obvious bilaterality of 7. ovinum. T. mutabile also has similarities with the species T. longiseptatum, reported by Soshkina (1951, p. 38) from Frasnian strata of Timan. The species are similar in size and number of septa and in having large pre- sepiments. 7. longiseptatum is characterized by the presence of complete, arched tabulae which serve to differentiate it from the Iowa form. 7. mcconnelli, as described by Smith (1945, p. 59), very closely resem- bles some specimens of 7. mutabile. Medium-sized in- dividuals of the former are approximately the same size and contain approximately the same number of septa, which are undilated in both species. There is more bilaterality shown in 7. mcconnelli, but the fact remains that the two species are probably closely re- lated, and the species from western Canada, when re- studied may be found to be the senior synonym of 7. mutabile. Occurrence.—T. mutabile occurs within the upper portion of the Mason City Member of the Shell Rock Formation, and has been collected from Localities 16 (Tom Williams Quarry), 17 (Baumgardner’s Mill), 18 (Kapka’s Farm), and 19 (Cooper’s Bend, see Appen- dix). In addition, Belanski collected several specimens from the same level of the Mason City Member farther south, in the neighborhood of Greene, Iowa, on Cold- water Creek (Locality 126, Strimple and Levorson, 1969, p. 269). Etymology.—The holotype and three paratypes are all selected from specimens collected by Belanski, whose collection labels bore this species name, appar- ently because the species shows considerable morpho- logical variability. Tabulophyllum curtum, new species Plate 1, figure 1; Plate 17, figures 5—11; Plate 18, figures 1-3 Diagnosis.—Large species of Tabulophyllum char- acterized by flaring turbinate form, large number of major septa and general development of lonsdaleoid dissepimentarium. Septa thick and minor septa more persistent than in most species of the genus. Corallites commonly deformed around or conforming to shape of neighbors. Description.—These are large corals when mature, with a broadly flaring calicinal platform. For the six corals thin-sectioned, the mean diameter is 53 mm, with a range from 27 for an immature form, to more than 70 mm for the holotype (Text-fig.33; PI.17, figs.5,6). The number of major septa ranges from 38 to 47, with a mean of 43.7. Mature corals of this spe- cies are normally in the neighborhood of 65 to 70 mm in diameter, with 46 or 47 major septa and an equal number of minor septa. Major septa are usually long and attenuate, leaving only a small open area at the axis. This characteristic is variable, and septa may at- tain the axis and leave only a small open area or none whatsoever. Major septa are heavy and maintain their thickness through the dissepimentarium into the tabu- larium. Minor septa are quite well developed, and are approximately , the length of the major septa. This characteristic is very much dependent on the width of the lonsdaleoid dissepimentarium, and on deformation during growth of corals which were in contact with and grew around other organisms or hard objects. Both the holotype (P1.17, fig.5) and one paratype (P1.17, fig.10) of 7. curtum show a square-cornered indentation in the side of the dissepimentarium. In the 46 BULLETIN 355 o a t ' 1 ' 1 1 ' Pe Nee Ee beers ee foe Wee ooh | Fe Na FY i PG feck | ~ @ oa oO Ry Sar ' 1 ' H 1 SeeNseedooe SS i 1 1 1 { Perera ees eee come Hae tee eed 1 ny lo” iS is) $3 = i Si lnes g a S T 1 1 1 1 ' total number of septa + i i \ \ \ i fet fe teaty Peery Poles (I Pott bok I | TAU leant etal 2 ace gc fees aaeriaaas| i) i) i) 55 aca a aaa en Fees (= ase a eS | 60 + t + — =< =| 3 5 6 7 8 9 corallite diameter in mm Text-figure 33.—Tabulophyllum curtum n. sp., from uppermost beds of the Mason City Member, corallite diameter (in mm) plotted versus the total number of septa in each individual. The holotype for this new species is indicated on the graph. holotype, the corallite was laterally compressed where in contact with a foreign object, and has an expanded lonsdaleoid dissepimentarium on the side away from it. In the paratype, the presepiments of the lonsdaleoid dissepimentarium appear to have provided an enlarged surface, enabling the coral to spread over and around its neighbor. Where expansion of the corallite was not inhibited, a broad development of lonsdaleoid disse- pimentarium resulted, with both major and minor septa discontinuous, either seen as spines on presepiments or as spinose bumps on septotheca. Where the corallite is laterally compressed (PI1.17, figs.5,9), septa are thick and complete, and minor septa are nearly as thick and 7, as long as major septa. Dissepiments seen in transverse view commonly arch peripherally or have an irregular form. Septa tend to be somewhat dart-like, thickening peripherally. The overall appearance of the dissepimentarium of these corals approaches the “‘herringbone’’ appearance (P1.17, figs.5,8). Longitudinal sections of these corals show a very broad and prominent tabularium, with tabulae com- monly complete, sagging axially and upbowed towards the margin, with peripheral troughs commonly devel- oped in large or flat individuals (P1.17, figs.6,7). Dis- sepiments tend to be flattened, small, and only shal- lowly dipping towards the corallite axis. In one dis- sepiment, incremental centripetal growth can be seen in thin section (PI.18, fig.3). Presepiments have the same orientation, and tend to be large, flat and elon- gate, and shallowly dipping, as they form the main skeletal elements for the flaring of the shallow cups. The structure of the corallite wall is septothecal, with peripheral ends of septa dilated to form the wall (P1.18, fig.2), even though these septa may only be short spines in the outer lonsdaleoid dissepimentarium, when well-developed. The septal structure is com- posed of very fine monacanth trabeculae (P1.18, fig.1). Type Specimens.—Holotype PRI 44721; paratypes SUI 707, 1435 and 853, PRI 44722. Discussion.—Although the types of this species show deformities by growth around neighboring ob- jects, this is obviously a result of their microenviron- ment. Several specimens assigned to this species have an elongate ovate shape, and this apparently is the pre- ferred form for individuals that have grown freely. T. curtum, with its characteristic septal dilation and outer lonsdaleoid dissepimentarium, is dissimilar from most species of Tabulophyllum. This septal dilation 1s reminiscent of that seen in the large Lime Creek spe- cies, T. magnum and T. expansum, which however have their septal dilation more confined to the tabu- larium and innermost dissepimentarium, and have many more septa than the Shell Rock species. T. den- sum, described from Frasnian strata of Poland (Roz- kowska, 1979, p. 42), has spear-like septal dilation of the same type as 7. curtum, but differs by having a somewhat smaller size and heavier septal dilation. Occurrence.—The sample available consists of three individuals collected by me from Locality 8, Nora Dam (see Appendix), while the other three spec- imens, from the Belanski collection, are from his for- mer collecting locality approximately 200 meters north of the dam, the so-called Belanski’s Quarry. At both localities specimens of Tabulophyllum curtum are found in the uppermost layer of the Mason City Mem- ber. Etymology.—The species name for these corals is taken from cards in specimen boxes of the Belanski Collection. He had determined that this was a new species and had chosen this name. Apparently the term refers to the short, flattened form of the corals. Tabulophyllum levorsoni, new species Plate 18, figures 4—7; Plate 19, figures 1—3 Diagnosis.—Large species of the genus, character- ized by flaring shape, large number of septa and de- velopment of several stout walls formed by thick pre- sepiments, resulting in inner lonsdaleoid dissepimen- tarium containing septa and an outer dissepimentarium lacking septa. Description.—Five specimens varying in age and preservation range in diameter from 26 to 55 mm in diameter, with from 31 to 51 major septa. The means for this sample are 42 mm for mean diameter, and 43.5 major septa. Two of these specimens are immature, thus three mature corallites are 50 to 55 mm in di- ameter, with 49 to 51 major septa. Major septa are long DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 47 and extend well into the tabularium, but leave approx- imately Y, of the tabularial diameter free of septa ax- ially. Septa are straight and are attenuate in the tabu- larium. Minor septa extend only slightly into the ta- bularium. Septa are radially arranged, with only a slight hint of a pinnate arrangement around the car- dinal area where there is a ladder-like appearance to dissepiments in transverse section (PI.18, figs.4,7). Rows of dissepiments are curved outward when seen in transverse section, flattening peripherally. They are commonly thick and form concentric interior wall seg- ments between septa (P1.18, fig.4). Presepiments are large, always interrupt minor septa and sometimes also interrupt major septa. Septa are thick at presepiments and are dilated in the inner and medial parts of the dissepimentarium, then are attenuate in the tabularium. The outer part of the dissepimentarium is clearly de- lineated, as it contains presepiments only, without any septa except that both major and minor septa are part of the septotheca and occur as bumps on the outer wall. Both major and minor septa are complete in the inner part of the dissepimentarium but are present as spines only on presepiments. The structure of the presepimental “‘walls” is most often lamellar, as common in Tabulophyllum, but from place to place a prismatic structure can be seen where the wall is less altered diagenetically (PI1.19, fig.1). The wall is septothecal (P1.19, fig.2). Microstructure in sep- ta in transverse section shows the axial plane of the septa formed of very fine monacanth trabeculae. A longitudinal section of the same specimen reveals the tabularium characterized by many flat, complete tabulae, with incomplete tabulae sagging or leaning on them, and amplexoid septal bases shown (P1.18, fig.5). In the periphery of the tabularium, gutters are devel- oped uniformly on both sides, with upbowed tabulae arching before resting on the central tabularium formed of flat-topped tabulae. The dissepimentarium is formed of flattened elongate, steeply inclined dis- sepiments, which are irregular in size and shape and form rows which are inclined in a straight fashion, rather than arching upwards. Septal structure shows fine monacanth trabeculae in longitudinal section, with trabeculae steeply inclined in the dissepimentarium, perpendicular to the rows of dissepiments. In the outer tabularium, growth lines can be seen as well as fine trabeculae (PI.19, fig.3). The outer wall of the corallite is clearly septotheca (P1.19, fig.2). Type Specimens.—Holotype PRI 44723; paratypes PRI 44724, 44725, 44726, 44727. Discussion.—Tabulophyllum levorsoni is unique due to a combination of its septal dilation, develop- ment of “‘inner’’ walls, and extensive presepiments. As seen on Plate 18, figures 4 and 7, the presepiments occur in two bands, an outermost one at the extreme periphery of the dissepimentarium, with no through- going septa, and an inner one in which major septa are developed. Each of these bands is marked by a major thickening of presepiments to form a wall within the calice, with septa dilated to have a triangular base at the stereome of the inner walls. This characteristic, along with the ladder-like development of dissepi- ments in the cardinal area, separates the species from all other Tabulophyllum. Occurrence.—All specimens of this species were collected from the basal portion of the upper biostrome of the Nora Member of the Shell Rock Formation at Locality 21 (Appendix), South of Rockford, Iowa. Etymology.—The species is named for Calvin Le- vorson of Riceville, lowa, enthusiastic student of Up- per Devonian paleontology. Tabulophyllum buccinum, new species Plate 19, figures 4—10 Diagnosis.—Medium sized species of Tabulophyl- lum with variable number of thick septa, well-devel- oped lonsdaleoid dissepimentarium, and very thick wall. Description.—Specimens assigned to this species have diameters ranging from 19 to 34 mm, with a mean of 27 mm. The number of major septa is vari- able, with a range of from 28 to 44, and mean of 34.5 for eight specimens sectioned. These numbers vary enough to suggest that the sample of eight does not properly characterize this population, restricted to a single horizon in the lower Nora biostrome. Major septa are long to very long, either leaving a small open space at the axis, or withdrawn somewhat from the central tabularium. At various levels within corallites, septa are short, leaving the axial area open. Minor septa are variable, at most 7, the length of major septa, and commonly only /, the length of major septa. The axial area is generally less than /, of the total area, without septa. Septa that are longer reach near the ax- ial portion of the corallite. Septa generally taper in- ward from the septothecal wall. In transverse section, the tabularium is characterized by the occasional appearance of tabulae, as seen in the plane of the transverse thin section. Intersection of sep- ta with dissepiments commonly results in swelling of septa and deposits of calcite at the point of juncture. In transverse section, these corals show pronounced and well-marked lonsdaleoid dissepimentaria formed by large presepiments at the outer wall (PI1.19, fig.4). The presepiments are very large and few in number. The epithecal wall is generally a thick one, occasion- ally (P1.19, figs.9,10) with a septothecal internal struc- 48 BULLETIN 355 ture. These corals are commonly crushed as a result of compaction of reefy accumulations of skeletal ma- terial. In longitudinal section, the species is characterized by flat-bottomed or sagging complete tabulae (PI1.19, figs.5,7). In the peripheral portion of the tabularium there is arching of tabulae. Dissepiments are small and steeply inclined adaxially. Corallites may have few or no dissepiments on one side and large, abundant, steeply inclined to sub-vertical dissepiments on the other side, probably reflecting reaction to change in orientation with respect to soft substrate. The external wall is prismatic in structure where very well-pre- served, and has a septothecal structure (PI1.19, figs.9,10). Septa have small diameter monacanth tra- beculae, with fibronormal structure both in septa and in epitheca (P1.19, figs.9,10). Type Specimens.—Holotype SUI 1282, paratypes SUI 1255, 1285, 141, and PRI 44728. Discussion.—Tabulophyllum buccinum is a species of medium size and medium number of septa for the genus. Its very large dissepiments and presepiments apparently indicate that it should be treated as a sep- arate species. These corals are difficult to categorize Although not conspecific, 7. buccinum resembles the Givetian species 7. traversensis from Michigan. Occurrence.—These corals are found within weath- ered outcrops of the lower Nora biostrome in the Reed Creek area, the “Reed Creek Phase”? of Belanski (1927, p.359). The exception to this is one specimen, part of the Belanski Collection (SUI 1083), which is labeled as coming from the uppermost bed of the Rock Grove Member at Rockford (the “‘Strobilocystites zon- ule” of Belanski, 1927, p. 353). Belanski noted that this bed is not present at any other outcrops of the Rock Grove Member, presumably being absent due to pre-Nora erosion (p. 353). Most solitary corals from the lower Nora apparently belong to 7. buccinum, a poorly defined group which occurs in or adjacent to biostromal environments of the lower Nora. Etymology.—The holotype and several other indi- viduals assigned to this species were so named in col- lections by Belanski. Tabulophyllum, species A Plate 1, figure 2; Plate 20, figures 1,2 Diagnosis.—Medium-sized coral with smooth oval outline in transverse section, numerous long major septa, small open area at axis, and large bulbous pre- sepiments forming lonsdaleoid dissepimentarium. Description.—The only specimen of this species of Tabulophyllum has a smoothly rounded oval outline in transverse view. The diameter is 20 mm along the short axis and 32 mm on the long, with an open axial area with diameters of 4 and 6 mm. The coral has 34 major sépta, which are attenuate and numerous for this diameter. Major septa extend to the corallite axis with a small open area at the axis. Minor septa are present as spines on the outer wall, or may be more complete, and as much as 7, as long as the major septa. In transverse section the presepiments are large and bulbous (P1.20, fig.1). The outer wall is septothecal, but has a weakly developed lamellar appearance in its outer portion. In longitudinal section tabulae are steeply inclined in the outer part of the tabularium and flat-bottomed at the corallite axis where amplexoid septa are based on the tabulae (P1.20, fig.2). The majority of tabulae tend to sag axially and have incomplete tabulae steeply stacked against the outer tabularium. There are abun- dant elongate, steeply dipping large presepiments and small dissepiments, all inclined axially at a large angle. Discussion.—This specimen of Tabulophyllum ap- pears to be a separate species, in which its oval form seems to be characteristic, along with its thick wall and large, bulbous presepiments and prominent inter- nal walls. Occurrence.—This coral was collected from the lower biostrome of the Nora Member of the Shell Rock Formation at Locality 4, Reed Creek (Appen- dix). Tabulophyllum, species B Plate 20, figures 3,4 Diagnosis.—Large ovate coral with elongate, thick septa. Minor septa well-developed and may approach thickness and length of major septa. Thick dissepi- ments and presepiments have an arcuate appearance in thin section. Description.—This coral is large and oval in out- line, with a long diameter of 50 mm and a short di- ameter in excess of 34 mm. There are 50 major septa, which are long and attenuate, reaching to the corallite axis or past it, thus no open axial space exists (P1.20, fig.4). Septa are stout and thickest at presepiments, which interrupt both major and minor septa. Attenuate septa are thin in the tabularium, but thicken slightly near the axis. There are numerous thick dissepiments or presepiments and these generally bear minor septa as spines, even if only very short. In the outer wall, both major and minor septa are present only as bumps or short spines. Minor septa are well developed, es- pecially at one end of the corallite, where they are uninterrupted and about , as long as the long major septa. The septa join together at their bases and form septotheca on the outermost presepiment. In longitudinal section the numerous large arcuate presepiments form much of the dissepimentarium DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 49 (P1.20, fig.3). They are steeply dipping, with their long axes not varying much from the orientation of the wall. Tabulae are flat and straight in the axial area of the corallite and sag somewhat around the margins of the tabularium. Dissepiments are numerous with pre- sepiments interspersed, but the two are so similar that it is not always possible to tell one from the other. Discussion.—This single specimen, collected by Belanski, has septal dilation similar to that seen in 7. curtum of the Mason City Member, and indeed could be conspecific. It is not placed in the latter due to its solitary occurrence in the collections made to date in Shell Rock beds, and its vertical separation from 7. curtum of the Mason City. Occurrence.—tThe coral is from the lower biostro- me of the Nora Member of the Shell Rock Formation at a locality that he referred to as Baumgardner’s Creek, but which has since been obliterated by quar- rying operations at Locality 16, Tom Williams Quarry (Appendix). Genus TARPHYPHYLLUM McLean and Pedder, 1984 Tarphyphyllum McLean and Pedder, 1984, p. 27 Type Species.—Tarphyphyllum besti McLean and Pedder, 1984, p. 28. Diagnosis.—Solitary or weakly fasciculate corals characterized by cylindrical form, fine septal trabecu- lae, weakly developed minor septa and lonsdaleoid dissepimentarium. Septotheca is thick. Discussion.—The genus was established by McLean and Pedder to include, among others, four species from Frasnian strata in western Canada. These authors placed Tarphyphyllum in the Family Kyphophyllidae Wedekind, 1927, whose genera are united by the pres- ence of very fine septal trabeculae, the development of presepiments and an accompanying lonsdaleoid dis- sepimentarium, and by characteristic complete tabulae in the very broad tabularium common in genera of the family. McLean and Pedder (1984, p. 28) noted that Ta- bulophyllum can be distinguished from Tarphyphyllum by 1) being exclusively solitary, and 2) having a wider and better developed dissepimentarium. In the Shell Rock fauna, Tarphyphyllum apparently is closely re- lated to thick-walled species of Tabulophyllum, and only separable from Tabulophyllum by the latter’s characteristic development of lonsdaleoid dissepimen- tarium with multiple presepiments and a thin septothe- ca, whereas Tarphyphyllum generally has few or no presepiments and a very thick septotheca. The two genera, correctly placed together in a single subfamily of the Kyphophyllidae, are obviously very closely re- lated, and might even be regarded as distinct only at the subgenus level. The difference between the two in the Shell Rock biostrome of the lower Nora Member can be slight. A thick-walled species of Tabulophyllum at this level has septotheca much like that of Tarphy- phyllum, while the latter, when a lonsdaleoid dissepi- mentarium is developed, is quite similar to the former. McLean and Pedder also remarked that Tarphyphyllum can be difficult to differentiate from some Smithiphyl- Jum in Frasnian rocks of Western Canada. As all Shell Rock Tarphyphyllum are solitary or weakly colonial, there is no difficulty separating it from the fasciculate species, Smithiphyllum belanskii, the only other ky- phophyllid seen in this unit. Of the four species of Tarphyphyllum described by McLean and Pedder in 1984, only the type species, T. besti, is solitary. All of the Shell Rock specimens of this genus are solitary, with the exception of one in- dividual which is twinned. Tarphyphyllum cylindricum, new species Plate 20, figures 5—10; Plate 21, figures 1—4,8 Diagnosis.—Solitary species of the genus with cy- lindrical growth form, sparse dissepiments, uniformly short minor septa, very thick septotheca and small di- ameter. Description.—Individuals of Tarphyphyllum cylin- dricum are small, exclusively solitary and cylindrical in shape, with a moderate number of septa. The avail- able sample consists of 24 corallites ranging in di- ameter from 8 to 15 mm, with a mean of 12 mm. The same corals have a mean number of major septa of 24.4, with a range of from 22 to 28 (Text-fig. 34). Major septa are generally long, extending nearly to the corallite axis, leaving a small open area at the axis. In this sample, the open area ranged from nil to a maximum diameter of 4 mm, while the mean open diameter was 2 mm for 22 specimens. The major septa are amplexoid, and thickest at the corallite wall where they form septotheca, and they maintain their thickness throughout most of their length. If long, major septa may swirl somewhat around the corallite axis, but only a few of them are in lateral contact. Their perceived length is somewhat dependent on where thin sections are cut, because just below a dominant tabula, the open axial space is largest. Minor septa are always short, commonly no more than spines on the septotheca, but can be up to 4% as long as major septa. Where a pre- sepiment is well developed, minor septa occur as short spines on it. Major and minor septa together expand greatly at the wall to form the typical septotheca. Where septa are short, tabulae are complete within the wide tabularium. Tabulae are rather irregular, with portions upbowed and wavy, especially over septal segments, and with peripheral gutters lacking (PI1.20, 50 BULLETIN 355 | (el fy | total number of major septa ' ' : ——+ 6 8 10 12 14 16 18 20 corallite diameter in mm Text-figure 34.—Tarphyphyllum cylindricum n. sp., from the low- er biostrome of the Nora Member, corallite diameters (in mm) plot- ted versus number of major septa in each corallite. Holotype and one paratype for this new species are identified on the graph. fig.5), or tabulae may slope axially from the margins of the tabularium and be sharply downbowed at the axis. Tabulae have a demonstrably fibronormal micro- structure where sufficiently unaltered. Dissepiments and presepiments are rare and commonly engulfed by biogenic stereome of the wall or septa (PI.21, fig.2). There are seldom more than two rows of steeply dip- ping dissepiments developed at any level within the corallites, and none whatsoever are present throughout most of the immature portions of the corallites (P1.20, figs.5,8). The few dissepiments seen are elongate ver- tically, and have their long axis parallel to the cylin- drical septotheca. Thus, a lonsdaleoid dissepimentar- ium may be totally lacking in the greatest part of most transverse sections of these corallites, which aids in distinguishing them from species of Tabulophyllum. The greatest development of lonsdaleoid dissepiments (rare) is up to Y, to Y, of the perimeter of the corallite. Septothecal structure here is typical of Tarphyphyl- lum. Septal bases are composed of crystallite fibers directed laterally to join with those of neighboring sep- ta to form a thick and complete wall (P1.21, figs.1,8). In longitudinal section, these fibers are bundled in ex- panding crystallite clusters and are analogous to the septotheca seen in living scleractinians, except for mineralogy. In some specimens these laterally directed calcitic fibers have been modified into a pseudo-la- mellar wall structure, especially on the outer rim of the wall. Type Specimens.—Holotype SUI 1291, paratypes SUI 1290, 1250, and PRI 44730. Discussion.—This species is not likely to be con- fused with described species of the genus. Although T. besti from western Canada may sometimes be sol- itary, it is a larger coral, with diameters ranging from 13.5 to’16 mm, and with fewer septa, generally 24 or 25 major septa in mature forms. Minor septa are not seen except in the septotheca. The other Frasnian forms described by McLean and Pedder are all fascic- ulate. Tarphyphyllum cylindricum is related to corals as- signed to species of Tabulophyllum which occur in the same strata at the same localities. If this is an artifact of nomenclature, then it is a very convenient artifact. The construction of the septotheca in this species, and diagenetic modification of it in a few corals helps in understanding biocrystallization of the outer wall, as well as its diagenetic modification in species of Ta- bulophyllum, Smithiphyllum, and other kyphophyllids. Occurrence.—All specimens assigned to Tarphy- phyllum cylindricum were collected from the lower biostrome of the Nora Member. They occur abundantly in outcrops at Reed Creek, north of Nora Springs (Lo- calities 3,4,5 Appendix) and sparsely in Locality 21 (Appendix). Etymology.—tThe Belanski specimens were grouped in his collection and tentatively given this species name by him prior to his death. Tarphyphyllum, species A Plate 21, figures 5—7, 9,10 Diagnosis.—Large diameter species of the genus characterized by oval form, numerous septa, and twinned form. Description.—This large twinned cylindrical indi- vidual has an oval outline in transverse section, with diameters of 25 and 15 mm in one individual and 24 and 14 mm in the other, although the second corallite is eroded and its diameter altered (P1.21, Fig.6). The former corallite has 34 major septa and the latter has 33: The number of major septa in these two corallites is typical for species of this genus. Septa are amplex- oid, and may be long, reaching almost to the corallite axis, so that one twin has a small open space (1.2 mm x 2 mm), while the other has much shorter septa in thin section, with a larger axial open space (5.3 mm x 9 mm). Length depends on where amplexoid septa are intersected by the transverse thin section. Major septa are thickest at the outer wall and progressively atten- uated inward. Peripherally they expand to form the septotheca. Where major septa are long, they tend to swirl around the corallite axis, but leave a small open area at the axis. Minor septa are well developed but short. Where major septa are short, minor may be up to 4, as long. Minor septa are broken by all prominent dissepiments and presepiments, and occur only as spines on septotheca and presepiments. DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 51 One individual has only minor development of a lonsdaleoid dissepimentarium at the two elongate ends of the corallite, while the other has presepiments ex- tending laterally to form /) to % of the perimeter (P1.21, fig.6). In a thin section of the juvenile part of the corallum, it is apparent that corallites are truly joined, and that the septa are amplexoid, with tabulae uparched, seen as ovals in transverse section (P1.21, fig.5). One ju- venile has 29 major septa with a minor diameter of 10.5 mm, and the other has 27 major septa where the minor diameter is 8 mm. In longitudinal section, tabulae are dominantly steep sided and flat bottomed. Tabulae are clustered dramat- ically (P1.21, fig.7). The clusters develop on a major, flat-bottomed tabula where amplexoid septa are based, and partial tabulae are developed as inclined or bowed or arched forms. The clusters are spaced 4 to 5 mm apart and each cluster has seven to ten tabulae per set. Presepiments and dissepiments are steeply inclined. The structure of the septotheca is clearly shown in longitudinal section where spherulitic clusters of cal- cite crystallites make up the wall and peripheral parts of septa (PI.21, fig.10). In transverse section of the adult part of the corallum, this septotheca is somewhat modified and beginning to take on a pseudo-lamellar aspect (PI.21, fig.9). Discussion.—This species is apparently unique among those assigned to Tarphyphyllum as it is of large diameter and has an oval cross section. The twin corallites are much larger in diameter than described species of the genus, including T. besti, the type spe- cies. Since I only have one specimen of this coral, I am not formalizing it, but simply report and figure it as a part of the Nora fauna. Occurrence.—This single specimen originated in the upper biostrome of the Nora Member at locality 21, South of Rockford (see Appendix), and was col- lected by Calvin Levorson. Genus SMITHIPHYLLUM Birenheide, 1962 Smithiphyllum Birenheide, 1962, p. 81; Pedder, 1965, p. 618; Hill, 1981, p. 229; Birenheide, 1986, p. 6; McLean and Pedder, 1987, p. 149. Type Species.—Spongophyllum imperfectum Smith, 1945, p. 55. Diagnosis.—(Following McLean and Pedder, 1987, p. 149) Fasciculate to subcerioid colonial coral with variably developed peripheral stereozone which does not interfere with development of dissepiments or pre- sepiments. Presepiments generally large and steeply inclined, but may not be consistently developed throughout ontogenetic development. Major septa gen- erally long and slender (but not in the lowa fauna), with minor septa variably developed. Tabulae are com- monly complete and may be flat, or either arch or sag. Discussion.—Birenheide (1962) erected the genus Smithiphyllum within the family Spongophyllidae to accommodate colonial species, mostly North Ameri- can, with presepiments and thin sparse septa. These had been referred to the genus Spongophyllum by Stumm (1937, 1949) and Smith (1945). S. imperfectum (Smith) was selected as type species of the new genus. Pedder (1965) elaborated on the species of the genus, emphasized the relationship between Smithiphyllum and Tabulophyllum, placed both in the Endophyllidae, and authored the species S. belanskii, from the Shell Rock Formation of Iowa. The lamellar skeletal struc- ture was described by Pedder from Smithiphyllum as being “that preserved” (avoiding the question of whether it is biogenic or diagenetic). I regard this as a secondary feature acquired during diagenesis of orig- inal skeletal structure (Sorauf, in press). Hill (1981, p. 229) followed Pedder in placing Smithiphyllum within the Endophyllidae. Birenheide (1986, p. 6) also considered that a sub- genus Smithiphyllum (Smithiphyllum) included all pha- celloid species of the genus, while a subgenus Smithi- phyllum (Parasmithiphyllum) McLean and Pedder, 1984, includes cerioid species. I prefer to leave these two distinct forms as separate genera, as proposed by McLean and Pedder. McLean and Pedder’s monograph (1987) on Smi- thiphyllum in western Canada, included all species known to date from North America, including S. be- lanskii, which occurs in western Canada as well as in the Shell Rock beds of Iowa. The reader is referred to this monograph for more extensive treatment of the genus and its species. The authors also discussed the Family Kyphophyllidae Wedekind, 1927, which in- cludes among others, Smithiphyllum, Tabulophyllum, and Tarphyphyllum. Smithiphyllum belanskii Pedder, 1965 Plate 22, figures 1—6; Plate 23, figures 1-5 Smithiphyllum belanskii Pedder, 1965, p. 623, Pl 88, figs. 1—3,5, PI. 89, figs. 13, 16; McLean and Pedder, 1987, p. 155, Pl. 5, figs. 1— 5; McLean and Sorauf, 1989, p. 395, Pl. 3, figs. 5, 10. Diagnosis.—Species of the genus with short, thin, somewhat radially arranged septa. Minor septa not no- ticeably developed. Young corallites commonly lack presepiments, but mature individuals have develop- ment of heavy interior wall surrounded by lonsdaleoid dissepimentarium with very large, steeply dipping pre- sepiments. Septa present on exterior wall as low ridges only. Tabulae usually complete, flat where septa are present, but sag irregularly elsewhere. Description.—Smithiphyllum belanskii is generally Nn NO T T 1 belanskii Smithiphyllum Total number of septa per corallite 8 + i i i \ I Corallite Diameter - mm Text-figure 35—Smithiphyllum belanskii, from the lower, bios- tromal part of the Mason City Member, corallite diameter (in mm) plotted versus number of total septa for individual corallites of this colonial species. The four corallites described in the holotype colony are also indicated. fasciculate, but where budding was frequent, it forms compact, subcerioid colonies. Walls in lateral contact become fused into a typical cerioid wall. Corallites are medium-sized, with diameters of mature individuals ranging from 8 mm to 17 mm, with a mean outside diameter of 11 mm in 37 corallites measured in eight colonies (Text-fig. 35). In transverse thin section, corallites are marked by short, attenuate, spine-like septa with their greatest thickness at the wall (either the outer, epithecal wall or an inner wall formed by thickened presepiments). Septa all appear alike, and lack symmetry (PI1.22, figs.2,3,4,6). There apparently are no minor septa. The number of septa ranges from 14 to 25 in colonies stud- ied, but mature corallites range from 18 to 25, with a mean number of 21.4 septa for 37 corallites in eight colonies (Text-fig. 35). Septa are generally not devel- oped in the lonsdaleoid dissepimentarium where pre- sepiments form open peripheral space. Septal ridges are sometimes developed on the inside of the epithecal wall and appear as stubs in transverse section. Septa are short in the tabularium; their length is generally /, to Y, of the radius of the tabularium, so that there is al- ways a large open space at the axis of corallites. At the extreme are corallites with only very short septal spines developed on the presepiments. Presepiments are large, and single ones may occupy as much as /, of the perimeter of the corallite (P1.22, figs.2,3,4). The inner wall formed by presepiments is commonly thick and may be angular as a result of interfering presepiments. Corallites may reach consid- erable size in some colonies prior to formation of pre- sepiments, and have thick external walls. The largest BULLETIN 355 of these has an outer diameter of 8.8 mm and contains 19 septa. In a compact colony such as that seen in Plate 22, Figure 6, the heavy walls of corallites are compressed against those of neighbors, approaching a ceriod colonial form. Various stages of development are seen, with presepiments commonly not formed un- til attainment of considerable size. Some corallites commence formation of presepiments in corners rather early in their growth. In longitudinal view, tabulae dominate the skeletal structure (P1I.22, fig.1). Tabulae are commonly com- plete and flat, especially in the space between septa, where septa are present. Where presepiments are formed, they are greatly elongate downward so that the calice had a very deep pit, with a flat floor com- posed of tabulae, and steep sides formed by presepi- ments. Presepiments tend to fill in bulges in the cor- allites where walls expand outward. Where septa do not extend into the tabularium, tabulae tend to be ir- regular and sagging. Tabulae in these colonies (PI1.22, fig.5) thus are much more irregular than typical, and they are characterized by regions of even greater ir- regularity, both in completeness and configuration of the tabulae. The microstructure of septa and walls is extremely well-preserved in some Iowa specimens. Septal struc- ture shows very fine monacanth trabeculae, with an approximate diameter of 0.1 mm (PI. 23, fig. 2 shows about 27 in 3 mm). Seen in longitudinal sections they make a high angle with the corallite wall (inclined 70° inward). Where unaltered, the structure of the corallite wall is fibro-normal and septothecal (P1.23, figs.3,4,5), not lamellar as frequently noted in the literature. Type Specimens.—Holotype SUI 11616, paratype SUI 11617, both from the Mason City Member of the Shell Rock Formation at Nora Springs, Iowa. Discussion.—The species was well described by Pedder (1965, p. 623), and additionally by McLean and Pedder (1987, p. 155). The latter noted that S. belanskii individuals from western Canada are larger than those from Iowa, ranging up to 2.0 cm in diam- eter, with up to 27 major septa (1987, p. 155). Several specimens from the Mason City Member display remarkable preservation of epithecal wall structures (P1.23, figs 1,3,4). These specimens are completely surrounded by encrustations of stromato- poroids, and this seems to help preserve the original structure from diagenetic change. Generally, the wall structure most often seen is modified lamellar, with septal bases affecting the development of (diagenetic) lamellar structure. This lamellar structure of walls is also very irregular in places. Diagenetic change was probably easiest in the fine crystals of the septa (So- rauf, in press). DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 53 Occurrence.—Smithiphyllum belanskii is found only in the basal biostromal unit of the Mason City Member. Pedder (1965, p. 623) reported that both the holotype and paratype were collected by him from the Mason City at Nora Springs. This is the type section of the Mason City (Locality 9, Appendix), where the basal biostrome is thick and well developed. Numer- ous topotypes were collected during the present study. The only other locality where S. belanskii was col- lected was from the Tom Williams Quarry, south of Nora Springs (Locality 16), where the lower biostrom- al unit is thin, but contains this coral species in its uppermost beds. These were the only localities where I was able to study the basal (biostromal) unit of the member. Order COLUMNARIINA Soshkina, 1941 Family CHARACTOPHYLLIDAE Pedder, 1972 Pedder proposed the Charactophyllidae for solitary corals with coarse monacanth septal trabeculae that are ‘seen to be flexed first downwards, and then, provided the septa are sufficiently long, upwards, when traced adaxially” (1972, p. 698). This character unifies a group of genera that also show numerous globular dis- sepiments and variably dilated septa. I accept the def- inition of Pedder. In the 1981 revision of the Rugosa for the Treatise on Invertebrate Paleontology, Hill placed the Char- actophyllidae (with a query) into synonymy with her Subfamily Disphyllinae, in the Family Disphyllidae Hill, 1939 (1981, p. F264). She noted that, in the Dis- phyllinae, there are solitary, fasciculate and cerioid corals having septal trabeculae that are monacanths, and may be “parallel and steeply declined adaxially and waved at tabularial borders” (1981, p. F264). These were placed in a subfamily with genera having “half-fans” of trabeculae. This group of solitary gen- era with characteristic septal structure warrant treat- ment as a separate family, as proposed by Pedder. Included in the family by Pedder are the Frasnian genera Charactophyllum, Chostophyllum and Temno- phyllum. McLean (1993) has provided an overview of the family, including descriptions of the ten genera placed there by him. Charactophyllum is the only ge- nus of the family represented in the Shell Rock and Lime Creek Formations of Iowa. Genus CHARACTOPHYLLUM Simpson, 1900 Charactophyllum Simpson, 1900, p. 209; Fenton and Fenton, 1924, p.26; Smith, 1945, p.17; Stainbrook, 1946, p.415; Wang, 1950, p.219; Watkins, 1959, p.82: Altevogt, 1963, p.14; Pickett, 1967, p.41; Pedder, 1972, p.698; Hill, 1981, p.F267; Pedder, 1982, p.562; McLean and Sorauf, 1989, p. 392; McLean, 1993, p. 109. not Charactophyllum Soshkina, 1949, p.90; Soshkina, 1951, p.68; Spassky, 1960, p.50; Spassky, 1977, p.108; Birenheide, 1978, p.84. Type Species.—Campophyllum nanum Hall and Whitfield, 1873, p. 232, Upper Devonian (Frasnian) Lime Creek Formation, Rockford, Iowa. Diagnosis.—Solitary corals with charactophyllid septal structure of coarse monacanth trabeculae. Ap- proximately 60 septa of variable length, with minor septa much shorter than the major septa, which may reach near coral axis and swirl in a counter-clockwise direction. Axial ends of septa commonly dilated and amplexoid. Dissepiments vary in number but always globular, arranged in steep rows, and vary in number from one to nine per row in the type species. Tabulae commonly complete and flat in axial portion of coral. Numerous steeply inclined tabular segments form tran- sition zone between tabulae and dissepimentarium. In juvenile stages all septa long and dilated; in mature stages, septa alternately long and amplexoid, or short and withdrawn from corallite axis. Septa serrated (den- ticulate) along margin, but not carinate. Discussion.—Interpretation of the genus Characto- phyllum has been hampered by inadequate description and illustration of the type species, Charactophyllum nanum (Hall and Whitfield, 1873). The original spe- cies description by Hall and Whitfield, although vague and lacking an illustration of the type specimen, did note that the septa were “‘strongly denticulate on the edge” (1873, p. 232). Hall and Whitfield also recog- nized a species they named Zaphrentis solida, also characterized by denticulations on the septa, and with the same number of septa as Campophyllum nanum. This must be regarded as a synonym of Characto- phyllum nanum, as discussed below. When Simpson (1900) erected the genus Charac- tophyllum, he placed two species in it, the type species Campophyllum nanum Hall and Whitfield, 1873, and Cyathophyllum radiculum Rominger, 1876, a carinate form; this last, according to Rominger, originated in the Silurian of Drummond Island, Michigan, and Lou- isville, Kentucky (1876, p. 109). Stumm (1964, p. 51) later placed the Louisville specimens in the Silurian genus Tryplasma. The section of Charactophyllum nanum figured by Simpson (1900, p. 210, fig. 28) is a neotype (NYSM 3160/1) that was chosen by Simpson, since Hall and Whitfield did not specify or figure a specimen of Campophyllum nanum. It consists only of an overly thick, uncovered longitudinal “thin” section etched to make an acetate peel, which accompanies the specimen. Although lacking a transverse section, this longitudinal section shows the characteristics of the genus well, and is typical of the species in Iowa. Simp- son’s written description of the genus, however, was 54 BULLETIN 355 inaccurate in that Charactophyllum was described as carinate, “just as Heliophyllum” (1900, p. 210). Sub- sequently, some coral workers have continued to re- gard C. nanum as having carinate septa. It does not. The genus is not carinate. Fenton and Fenton (1924) were the first, after Simp- son, to study the Lime Creek corals, as part of their broader study of the strata and fauna. Although critical of the quality of Simpson’s description of the genus Charactophyllum, theirs was also inadequate, dealing mostly with external characteristics and they also made the mistake of misusing the term ‘“‘carinate”’, noting that, “the septa are strongly carinate, giving them a denticulate appearance in the calyx which does not, however, show well in the transverse sections” (1924, p. 25). On the same page they also noted that the car- inate (read denticulate) septa are the diagnostic char- acter of the genus. This is not an acceptable use of the term carinate, which must refer to structures expressed on the lateral flanks of septa, seen optimally in trans- verse thin sections. An additional error of Fenton and Fenton was in placing the Hall and Whitfield species Zaphrentis so- lida into the genus Heliophyllum. This species is a synonym of Charactophyllum nanum, Fenton and Fen- ton noted that “‘septa are strongly denticulate” (1924, p. 28), and did not mention carinae such as those that typify Heliophyllum. No carinae are seen in the trans- verse thin sections of “H’”’. solidum and C. nanum illustrated by them, and the species are identical (1924, Piel): Smith (1945) and Stainbrook (1946) both illustrated topotypes of Charactophyllum from Rockford, lowa, and their studies should have dispelled the notion that the genus has carinate septa. Although Smith wrote in his generic diagnosis that the genus has carinate septa (1945, p. 17), he figured transverse sections of three specimens that clearly show septa that are non-cari- nate. Stainbrook (1946, p. 415) noted that although the septal flanks appear to be ‘“‘carinated’’, they are not “typical carinae similar to those of Heliophyllum*, and ‘‘do not project into the interseptal loculi and are not evident in transverse and longitudinal sections”’. He preferred referring to the septa as “‘trabeculate rath- er than carinate”’ (1946, p. 415). This could have suf- ficed to indicate clearly the true nature of septa in this species. Some workers however, have continued to believe that Charactophyllum is a genus of solitary corals with carinate septa. Soshkina (1949, 1951) placed carinate species within the genus, and in addition, included the presence of fan-like septal trabeculae in her diagnosis of the genus (1951, p. 68). She also noted (1951, p. 73) that Heliophyllum differs from Charactophyllum only in that it has longer major septa which reach the corallite axis. Spassky (1960) accepted Soshkina’s concept of the genus. Birenheide (1978, p. 84) noted that Charactophyllum has ‘‘clearly to strongly devel- oped yardarm carinae on the septa’’. This is incorrect, and species placed in Charactophyllum by these au- thors must be re-examined. Wang (1950), Watkins (1959) and Altevogt (1963) each studied and discussed topotypic material of the type species. Wang (1950, p. 219) observed the im- portant characteristic, the ‘‘elbow-bending” of the monacanth septal trabeculae, later utilized by Pedder (1972, p. 698) as an important character of the Char- actophyllidae. Watkins (1959) and Altevogt (1963) helped to define the genus by illustrating additional specimens from the Lime Creek Formation of Iowa. Pedder, in two important papers (1972, 1982) has accurately diagnosed the genus, as well as providing an accurate and complete description of the type spe- cies (1982, p. 563). The papers of Pedder, along with the description by Hill (1981) insure that the genus Charactophyllum is now based on the morphology of C. nanum. Range.—This genus is abundantly represented in Frasnian faunas of Iowa and also in western Canada (Pedder, 1972, p. 698) as well as in Spain (Altevogt, 1963, p. 15). The genus has also been reported from the Ural Mountains of Russia by Soshkina and by Spassky, and from the Eifel Region of Germany by Birenheide, but these reports are potentially erroneous, as noted above. Charactophyllum nanum (Hall and Whitfield, 1873) Plate 2, figures 1-4; Plate 24, figures 1-15; Plate 25, figures 1-12; Plate 26, figures 1,2 Campophyllum nanum Hall and Whitfield, 1873, p. 232. Zaphrentis solida Hall and Whitfield, 1873, p. 231, Pl. 9, fig. 5. Charactophyllum nanum Simpson, 1900, p. 209, fig. 28; Fenton and Fenton, 1924, p. 26, Pl. 1, figs. 1-3; Smith, 1945, p. 17, Pl. 1, figs. 6, 7, 8a, 8b, Pl. 31, figs. la-1li; Wang, 1950, p. 219, Pl. 7, figs. 44a, 44b; Watkins, 1959, p. 82, Pl. 16, figs. 13-20; Altevogt, 1963; p: 15, Pl. 1. fig. 1; Hill; 1981), p: F267, figs. 171) Wa-f; Pedder, 1982, p. 562; McLean and Sorauf, 1989, p. 392, Pl. 3, figs. 8, 9. Heliophyllum solidum Fenton and Fenton, 1924, p. 28, Pl. 1, figs. 4-7. Diagnosis.—Type species of genus characterized by septa which are weakly bilateral in some individuals, with minor septa generally less than one-half as long as major; with distinctive septal structure, length vari- ations and dilation. Non-carinate septa with coarse monacanth trabeculae which flex downward in the dis- sepimentarium, and then flex sharply upward in the tabularium. Septa partially amplexoid, with length DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 55 varying in major septa from long, reaching almost to the corallite axis, to short, leaving as much as one- third of the coral as open axial area. Dilation varies from heavy in periaxial area in long septa to light or absent in short septa. Dissepiments small, globose, in one to nine steeply inclined rows; tabulae commonly complete and flat, with numerous steeply inclined small tabulae forming transition to dissepimentarium. Description.—Charactophyllum nanum includes corals of medium to small size with varying shapes, from trochoid to ceratoid (PI1.2, figs.1—4), with elon- gate forms more abundant. The calice is deep, flat- bottomed and steep-sided, reflecting steep rows of dis- sepiments. Septa in the calice are denticulate (having a toothed oral margin), and sides of septa are marked in the calice by subhorizontal ridges marking the po- sitions of coarse subhorizontal monacanth trabeculae. These are later obscured by biogenic calcite in dilated septa. Thus, septa are denticulate, ridged and may be somewhat knobby in cross section, but definitely are not carinate. In transverse section, septa of two orders are seen, with minor septa generally up to one-half the length of major septa. In 35 specimens with diameters rang- ing from 13 to 22 mm (mean of 15.4 mm) the number of septa range from 54 to 74 with a mean of 61.5 septa (Text-fig. 36). Seen in transverse section, septa appear knobby in the dissepimentarium, thickened at trabec- ulae and commonly also at the junction of dissepi- ments and septa. In adult parts of the corals, major septa commonly extend through 7, to ¥, of the tabu- larium, leaving a small open area at the axis (P1.24, figs.2,3,9,12,13). Septa may be weakly bilateral, ar- ranged around a short cardinal septum (P1.24, fig.3), or more typically, radially arranged with long septa swirled around the axial open space (P1.24, fig.6); or septa may be short and radial, with a large axial open area (P1.25, figs.1,5). The length of septa varies greatly during the life history of an individual. Septa are par- tially amplexoid, with maximum septal length occur- ring directly on and above a prominent thickened ta- bula. Septa in adult parts of the coral are usually di- lated in the tabularium if they are long, with swollen, inflated septa deflected around the axial region (PI1.24, figs.2,3). Short septa have their maximum dilation near the outer margin of the tabularium (P1.25, fig.5). Di- lation of long septa forms an axial boss in some in- dividuals. Dissepiments appear in transverse section as numerous arcuate intersections (with the small globose dissepiments). Where septa are dilated, dissepiments are commonly thickened by stereome. Where septa are long but less dilated, the innermost dissepiments are thickened and outline the tabularium. In juvenile parts of Charactophyllum nanum, septa n o | s 3 = QQ a ie) o nN oO t ' ' ' ' 1 ' ! Number of Major Septa De) a + \ ' ' ' ' —_ oa + 1 1 1 1 ' ' ' ST mR Gime aie fica ay (meen (cohen Prasat f=" aig broly Nee | eet te ee Ee ee Eee ee et ble ---1---1 ' Seer ' ' ' Hl un ' 1 1 fo} o+—= 10 15 20 25 30 35 Corallite Diameter - mm Text-figure 36.—Charactophyllum nanum, the most abundant cor- al in the Cerro Gordo Member, corallite diameter (in mm) plotted versus number of major septa for individuals of this solitary species. Included are forms that fit the description of Zaphrentis solida Hall and Whitfield, here placed into synonymy. The single specimen with the large number of septa shown at the top of the graph appears anomalous, but resembles the other members of the species in all other ways than number of septa. are generally thick throughout, and commonly are di- lated to touch laterally (P1.24, figs.5,8,15). Septa are long; normally the cardinal septum is short while the counter septum extends alone through the axial area of the coral. Where only one or two rows of dissepi- ments occur in juveniles, they appear as a row of clear vesicles outside a zone largely filled with stereome. In longitudinal section, several characteristics of the species (and genus) are clearly visible. The septa con- tain coarse, monacanth trabeculae (P1.25, figs.8,12), which have the characteristic charactophyllid config- uration (Pedder, 1972, p. 698). Seen in longitudinal section, trabeculae arise at an angle with the corallite wall and quickly bend to subhorizontal or more com- monly, slightly past horizontal, in the dissepimentar- ium, then bend sharply upward at the outer boundary of the tabularium and continue upwards in the axial region of the coral. The existence of prominent tabulae with heavily di- lated septa on and just above it also seems character- istic of the species. Septa are amplexoid, with a heavy base and with their greatest length on a prominent, thick tabulae. There is an alternation of a corallite form with shorter septa below these tabulae, and a form with longer, more heavily dilated septa just above. The dissepimentarium varies in longitudinal section, especially in the number of rows of globose, evenly- sized dissepiments. In adult parts of the corallite, there are from one to nine rows of dissepiments; generally there are more than three or four. Where there is a constriction in the coral diameter, there is a corre- 56 BULLETIN 355 sponding decrease in the number of rows of dissepi- ments. More elongate ceratoid corals tend to have few- er rows than do trochoid corals. In curved forms, there are generally more rows of dissepiments on the convex side of the coral (P1.24, fig.10). Tabulae are generally somewhat flat and complete in the axial area (P1.24, figs.4,10; Pl.25, figs.10—12). Periaxially, tabulae vary, but are commonly arched adorally, then are downbent to form a_ peripheral trough around the tabularium, or else are more irreg- ular and incomplete marginally. Small lateral tabulae are abundant, forming a transition into the steep rows of dissepiments. These tabulae are elongate and adax- ially inclined, with the same orientation as the rows of dissepiments. They may also be coated with stereome where they merge with prominent, thick tabulae. Spac- ing of tabulae varies periodically, with the greatest spacing just below thick, prominent tabulae with am- plexoid septa above. Type Specimen.—Simpson’s neotype, NYSM 3160/1 is a very thick longitudinal section (1900, p. 209, fig. 28, p. 210). Discussion.—Hall and Whitfield, although not fig- uring their species Campothyllum nanum (1873, p. 232) did describe and figure the species Zaphrentis solida (1873, p. 231). The descriptions of the two pro- posed species are similar, in that they both have a deep calice, denticulate septa, and a dissepimentarium with ““minute”’ dissepiments. The difference, as noted by them, is that Z. solida is “‘turbinate”’ (p. 231) while C. nanum is ‘“‘elongate-turbinate”’ (p.232). Both of these forms are common within the population of C. nanum studied by me. The type specimen of Zaphrentis solida is not present in the New York State Museum, and must be presumed lost. Fenton and Fenton recognized two abundant species of solitary corals in the Cerro Gordo Member, Char- actophyllum nanum (1924, p. 26) and Heliophyllum solidum (1924, p. 28). They noted that the more elon- gate form, C. nanum, is “the commonest rugose coral of the Hackberry” (p. 26), but also said that the ‘‘sub- conical to subturbinate”’ coral, H. solidum, “rivals Charactophyllum nanum in abundance” (p. 28). This is true, as sections of the Fentons’ topotypes of H. solidum (FMNH 26002, 26003) are certainly conspe- cific with C. nanum. The latter is extremely abundant in the Cerro Gordo beds of the Lime Creek Formation, outnumbering all others. In addition to variation in external shape, C. nanum also varies considerably in septal length and ornamen- tation, and in configuration of dissepiments and tabu- lae. Adult C. nanum vary a great deal in both length and thickness of septa. Two extremes are 1) corals with undilated septa, and either a large open axial area with short septa (P1.25, fig.5), or a small open axial area with elongate attenuate septa (P1.25, fig.9); and 2) corals with long, dilated septa, with heavy dilation in the tabularium sometimes resulting in an axial boss (P1.24, fig.2; Pl. 26, fig.2). Much less variation is seen in juvenile portions of the corals, where septa are in- variably long, most often with a short cardinal septum and a long counter septum which extends across the axis of the coral. This bilaterality is variably preserved into the adult state. Some C. nanum adults show bi- laterality around a short cardinal septum, but many more do not. Juvenile portions of C. nanum usually have dilated septa, and may be heavily filled with ster- eome, but some have much less heavy apical skele- tons. The shorter, trochoid corallites (the Z. solida form) most often have rather attenuate septa, especially so adjacent to the calice. In the calicinal area, the coarse monacanth septal trabeculae are shown in relief on the flanks of thin septa. This presence of almost horizontal trabecular ridges on the flanks of septa, accompanied by denticulations where the monacanths intersect the upper margin of the septa, impressed early workers and led to the false belief that these are carinate septa. Stainbrook later noted that “the ridges on the sides are due to trabeculae. The septa may be said to be trabe- culate rather than carinate”’ (1946, p. 415). Where sep- ta are dilated, these ridges are smoothed over by ster- eome in the thicker septa. The presence of these sub- horizontal ridges is seen in longitudinal sections of septa where monacanths bend to the subhorizontal po- sition in the dissepimentarium, and then bend sharply upward in the tabularium (P1.25, figs.10—12; P1.26, fig.1). This is the ‘“‘elbow folding” of Wang (1950, p. 242), and the “‘charactophyllid trabeculae” of Pedder (1972, p. 698). Variation in septal length and dilation is clearly seen within individual corals. In longitudinal section the amplexoid nature of these septa is seen in the periodic occurrence of sclerenchyme and septal trabeculae on some tabulae (P1.24, fig.4). Transverse sections just above such a tabula show long, heavily dilated septa, where transverse sections just below have shorter and thinner septa which are not dilated in the tabularium. A series of sections in a single coral may show alter- nations of forms of the dilated C. nanum type (PI. 25, figs.4,5,6) and forms closer to that regarded as Z. so- lida by Hall and Whitfield (1873) and by Fenton and Fenton (1924). In longitudinal section, variation in the number, size and thickness of plates is seen in dissepiments and neighboring tabulae (Pl. 25, figs.10—12). The number of rows of dissepiments is highest in flatter (trochoid) corals, and may be very numerous, especially on the DEVONIAN RUGOSE CORALS OF IOWA: SORAUF EY/ convex side of the coral. The dissepimentarium may also expand and contract during the life history of the individual, possibly as a response to changes in sedi- mentation rate. Also, these corals may have lived with their skeleton at least partially buried in soft sediment, so that the dissepimentarium was both adjacent to sed- iments and adjusted to their presence. There is also a variation in thickness and weight of tabulae and dissepiments, which apparently corre- sponds to periodic thickening of skeletal elements and building of long, dilated septa over them. This species is an extremely abundant one in the Cerro Gordo Member, and at the same time a variable one, with variation within individuals sufficient to encompass the variation which is seen in corallites where they form more elongate or less elongate shapes. Two papers by Pedder (1972, 1982) have clarified both the genus and species of Charactophyllum nanum as well as relationships to other genera of Pedder’s family Charactophyllidae. Descriptions of this species, as well as Zaphrentis solida show a history of mis- understanding of septal morphology because of misuse of the term “‘carination”’, and misapplication of the words “‘carinae”’ and “‘carinate”’ to the septa in these named groups. This history need not be further dis- cussed here, except to note that Z. solida is best left lapsed. The use of Campophyllum nanum by Simpson and all other authors as the type species of Charac- tophyllum mandates allowing this. In the Cerro Gordo fauna, there are no other corals which could be con- fused with Charactophyllum nanum and there is no doubt as to the identity of what was called Z. solida. Altevogt (1963, p. 15, Pl. 1, fig.1) additionally re- ported the species from late Frasnian rocks in Northern Spain. His illustrated specimen appears properly as- signed to C. nanum, greatly expanding the geographic range of the species. Smith (1945, Pl.1, fig.6) also fig- ured a transverse section through what he called Char- actophyllum sp., and this appears also to be a specimen of C. nanum, although with question. Occurrence.—Charactophyllum nanum occurs pro- fusely in the Cerro Gordo Member at all outcrop lo- calities. It was most abundant in the upper /, of the member at Bird Hill (Locality 31, Appendix) and ad- jacent outcrops. One specimen of Charactophyllum sp. cf. C. nanum has been found in the Owen Member at the Buseman Quarry, south of Dumont, Iowa (Locality 40). Also, the species apparently occurs in Frasnian strata of western Canada and Spain. Family DISPHYLLIDAE Hill, 1939 In the 1981 revision of the Subclass Rugosa for the Treatise on Invertebrate Paleontology, Hill placed in the Disphyllidae solitary and colonial corals with mon- acanth septal trabeculae which are, ‘““commonly in half fans, or in fans” (1981, p. F264). This terminology is misleading, because these fans are not similar to, nor are these genera related to, corals with symmetrically branched septal trabeculae that form fans as genera in the Phillipsastreidae. In the Disphyllidae, some corals with wide dissepimentaria have gently arched rows of dissepiments, and a resultant arching of septal trabec- ulae perpendicular to them can form a weak “‘fanning”’ of trabeculae as seen in longitudinal section (illustrated by Strusz, 1965, p. 524). I prefer not to utilize the same term (fan) for two very different features char- acteristic of the two families. While accepting in great part the generic composi- tion of the Family Disphyllidae as defined by Hill, I modify her useage in the following ways: 1. I do not accept her subfamily Subfamily Hexa- gonariinae, which she considered should include cer- ioid disphyllids with closely carinate, long, fusiform septa (1981, p. F274). This is based on a misinterpre- tation of Hexagonaria hexagona, in which “‘carinae”’ can occur, but only as part of a process of septal di- lation that includes the lateral expansion of trabeculae as part of the process, as discussed below under the genus. In this subfamily, Hill placed the genus Hexa- gonaria, which is closely related to Disphyllum, with Haplothecia and Marisastrum, which are not. I do not include them in this family, as discussed in Sorauf (1994, p. 333), and: 2. I exclude solitary genera with characteristic sharp flexing of coarse septal trabeculae, placing Char- actophyllum and related genera into the Charactophyl- lidae Pedder, 1972, as noted above. Genus DISPHYLLUM deFromentel, 1861 Cyathophyllum Goldtuss, 1826, p. 60 (in part). Disphyllum deFromentel, 1861, p. 302; Stumm, 1949, p. 33; Pickett, 1967, p. 22; Rozkowska, 1960, p. 7; Tsien, 1970, p. 162; Roz- kowska and Fedorowski, 1972, p. 296; Hill, 1981, p. F264; Ro- hart, 1988, p. 252; Sorauf, 1987b, p. 681; McLean and Sorauf, 1989, p. 392. Birenheide, 1978, p. 90 (in part); Birenheide and Gabrielli, 1993, p. 14 (in part). Heliophyllum Fenton and Fenton, 1924, p. 27. Diphyphyllum Fenton and Fenton, 1924, p. 42. Cylindrophyllum Belanski, 1928, p. 176. Type species.—Cyathophyllum caespitosum Gold- fuss, 1826, p. 26. Diagnosis.—Fasciculate colonial genus of the Dis- phyllidae characterized by radial septa in two orders, with monacanth septal trabeculae inclined inward from outer wall towards axis; septa with spindle-shaped di- lation and with well-developed, globular dissepiments. Tabularium consists of flat, cap-like axial tabulae and peripheral, sagging tabulae. Discussion.—The genus Disphyllum is a widespread 58 BULLETIN 355 Middle and Upper Devonian rugose coral, belonging to the cosmopolitan faunas of that time. It is also the nominate genus of Hill’s family Disphyllidae, and thus has an additional importance. Although the family Dis- phyllidae has been subdivided into four subfamilies by Hill (1981), I have elsewhere (1994, p. 333) pointed out problems with these subdivisions. The genus Dis- phyllum is central to the family and as nominate genus it must be clearly understood. Most authors who have studied Disphyllum have agreed on its basic morphology. The inclined mona- canth septal trabeculae, fusiform dilation of septa in the inner dissepimentarium, numerous rows of globu- lar dissepiments and common occurrence of axial and peri-axial rows of tabulae in corallites with long septa are all accepted characteristics of the genus. Problems of nomenclature can arise when narrow dissepimen- taria are developed, as these corals then may closely resemble species of the genus Columnaria. Taxonomic difficulties have also resulted due to variation in colonial form. Disphyllum caespitosum oc- curs as both purely fasciculate colonies and also in more compact colonies which are indistinguishable (at least in part) from cerioid genera. Birenheide (1978, p. 90) stated that both cerioid and fasciculate, noncar- inate corals of this group of the Disphyllidae should be placed in the genus Disphyllum. I suggested (1994, p.327) that Disphyllum should contain all those species that are dominantly fasiculate, accepting the tendency of some species to develop subcerioid colonies under certain environmental conditions. The problem does not arise in the lowa faunas because both Cerro Gordo and Mason City beds contain only fasciculate colonies of Disphyllum. A close relationship between some species of Dis- phyllum and species of the genus Peneckiella is indi- cated by a peripheral row of differentiated dissepi- ments present in some species, as in many colonies of D. floydensis and D. iowense, both described below. This is also distinctive in D. fasciculum, as identified by McLean and Sorauf (1989,p. 392). In both Iowa species there is a row of dissepiments in the periphery of the corallite which are uniformly larger and more bulbous than dissepiments internal to this row, and very commonly are thicker-walled than others. Es- pecially in D. iowense, when there is a stereome coat- ing forming a wall-like margin to the tabularium, the coating forms on the inner side of this row. In mature corals of these two species, there are always additional dissepiments interior to the peripheral row, but at one stage of corallite growth, there may be none. This fea- ture is well illustrated in D. fasciculum (McLean and Sorauf, 1989, pl. 2, figs. 6,7), and also in specimens illustrated by Rohart (1988, pl. 35, figs. 10-13). This feature led Rohart to place this coral species, from northern France, in the genus Peneckiella, but I would not regard the dissepiments in these individuals to be truly peneckielloid. In addition to the four species of Disphyllum de- scribed here, a single colony of an additional species was collected from the Owen Member from the base of the uppermost stromatoporoid biostrome, at the Buseman Quarry south of Dumont, Iowa (Locality 40, Appendix). This single colony is similar to medium- sized species of the genus with long septa, but is not well enough preserved to warrant illustration here. Disphyllum dispassum (Fenton and Fenton, 1924) Plate 26, figures 3-10 Heliophyllum dispassum Fenton and Fenton, 1924, p. 27, Pl. 10, figs. 4-8. Diphyphyllum tubiforme Fenton and Fenton, 1924, p. 42, Pl. 2, figs. 1-4. Diagnosis.—Small fasiculate colonies of Disphyl- Jum with major septa of varying length, generally open tabularium with flat and complete or upbowed incom- plete tabulae. Dissepimentarium narrow, with two or three rows of globular dissepiments most common, ex- cept where budding occurs in broadened dissepimen- tarium. Description.—Disphyllum dispassum occurs as small colonies in the shaly rocks of the Cerro Gordo Member of the Lime Creek Formation. Some colonies are compact in their young stages, where rapid bud- ding results in corallites commonly in lateral contact and prismatic, while generally in more adult (but still small) colonies, corallites are separate and truly fas- ciculate in form. In transverse section, individual corallites are small, with a mean diameter of 7.4 mm for 12 mature-ap- pearing corallites (range of 6.8 to 9.3 mm). These same corallites have a mean of 38.9 septa, (range of 36 to 44, Text-fig. 37). Septa are radially arranged, with clear differentiation into major and minor orders. The length of major septa varies, from short, extending at most Y, way through the tabularium toward the axis, to long, in which major septa extend ¥% or /% way to the axis and swirl, so that there is only a very small open axial space. This variation is seen within indi- vidual colonies (P1.26, figs.3,4,5,9), so that it cannot be used as a taxonomic character. The minor septa are almost invariably approximately one half the length of major septa, and are generally confined to the disse- pimentarium. The dissepimentarium is narrow. Septal dilation is variable also, some with short and thin septa (P1.26, fig.3) having weak, spindle-like dilation that only occurs in the outer tabularium. Other corallites have thicker septa which may be more heavily dilated DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 59 L 1 ' ‘ 1 ' ' f ==---=-- 1 1 ' 1 ' 1 ' ' 2 t Sere eee a op ~~~ t | Holotype - D. dispassum S ee a a ' 1 1 a I ' z -+-| Disphyllum dispassum [oor SSSSTSS5 20tf-<---- ba-------4--------4--------- posen naa panna nna- | |N=17 15 - t ae | 4 5 6 7 8 9 10 Corallite Diameter - mm Text-figure 37.—Disphyllum dispassum from the Cerro Gordo Member, corallite diameter (in mm) plotted versus the total number of septa in individuals from six colonies studied. The holotype of the species is indicated on the graph. in the outer tabularium (P1.26, figs.7,9). Where septa are thin, their path in transverse section can be irreg- ular, with septal trabeculae swollen somewhat to give a carinate-like appearance to them. In longitudinal section, corallites commonly have a mostly open tabularium, with tabulae either complete and flat or arched, or incomplete and inclined. Where septa are long, there may be the development of typ- ical disphyllid axial and peri-axial rows of tabulae. The dissepimentarium is generally narrow in this species, with two or three rows of globular, inclined dissepi- ments, expanding to many more rows of dissepiments prior to budding, which occurs in the outer dissepi- mentarium (P1.26, figs.6,8). Septal trabeculae are seen within septa in longitu- dinal sections. They incline adaxially at a rather uni- form angle from the wall, generally about 50° to 55° from the vertical. Type specimens.—Holotype FMNH 26045, para- type UMMP 7809. Diphyphyllum tubiforme, holotype FMNH 26014, paratypes FMNH 26015, UMMP 7853. Discussion.—On the basis of external morphology, Fenton and Fenton proposed two species of fasciculate corals from the Cerro Gordo, Heliophyllum dispassum (1924, p. 27) and Diphyphyllum tubiforme (1924, p. 42), which are synonyms. They noted that H. dispas- sum had about 40 septa that ‘“‘are strongly denticulate, and very heavy’’, and that D. tubiforme has 40 to 46 septa, that “‘are strongly carinate’’. The holotype of D. tubiforme was not sectioned; it does not have heavy or long septa (P1.26, fig.4), and the Fentons’ sections of paratypes of both species are virtually identical. Both have moderately long septa that are thick. The only real difference between specimens in the type col- lections is in colony form, as the holotype of D. tub- iforme budded rapidly in its early stages of colony growth, thus, it is almost cerioid in the packing of juveniles around the parent. Fenton and Fenton noted that both species are variable in colony shape, and D. dispassum is indeed variable, both in colony shape and also in length and dilation of septa. Disphyllum dispassum resembles D. caespitosum, as identified in the New York Frasnian fauna (Sorauf, 1987, p. 681). Both have long septa and three to four rows of dissepiments, with the outermost dissepiments larger and more bulbous than the rest, although the Iowa species has much less size and shape differenti- ation than does the New York form. Additionally, the septal trabeculae of D. caespitosum are much larger and more prominent than are those in D. dispassum. The Iowa species also is reminiscent of D. fasciculum in the differentiation of the outermost dissepiments, but the former has longer septa than does D. dispassum and only one or two rows of dissepiments. Occurrence.—Specimens collected by Fenton and Fenton came from the “Spirifer zone” or upper Cerro Gordo Member at the Rockford Brick and Tile Quarry (Locality 35, Appendix), with the exception of one specimen of D. dispassum, UMMP 7809, which was collected from the upper part of the Cerro Gordo at Bird Hill (Locality 31). Specimens collected by me came from the South Portland locality (Locality 27) and the type Lime Creek (Locality 28). In both of these localities, the small, fasciculate colonies were collected approximately 4 m (12 to 13 ft) above the “rusty bed’’. A single colony collected within the Cer- ro Gordo at Bird Hill (Locality 31) came from ap- proximately 6.5 m (20 ft) below the base of the Owen Member. Colonies collected at the Rockford Brick and Tile Quarry (Locality 35) were all from material of the upper Cerro Gordo that had been stripped from un- derlying shales and left in dump piles. Disphyllum floydense (Belanski, 1928) Plate 1, figure 3; Plate 27, figures 1—5; Plate 28, figures 1—4 Cylindrophyllum floydense Belanski, 1928, p. 176, Pl.12, fig.1. Diagnosis.—Species of Disphyllum with colony mean diameter of tabularium between 4 and 5 mm., but with some colonies with larger diameters in south- ern part of outcrop area (6.4—10.7 mm). Long, straight major septa extend almost to corallite axis; fusiform dilation of both major and minor septa in the inner dissepimentarium somewhat variable in development. Dissepimentarium narrow, sometimes with only one row of elongate, almost peneckielloid dissepiments, but with as many as four or five rows of smaller, glo- 60 BULLETIN 355 bose dissepiments. Tabularium characterized by axial series of flat-topped and periaxial series of sagging ta- bulae, usually interrupted in some parts of corallite by irregular inclined or incomplete tabulae. Description.—Disphyllum floydense colonies are fasciculate; rapid offsetting forms compact branching colonies. Colony size is generally 25 to 30 cm in di- ameter (Pl.1, fig.1), with height being /, that dimen- sion. In transverse section, radially arranged septa are clearly organized into two orders, with major septa extending almost to the axis of the corallite, leaving approximately ¥, of the diameter of tabularium open at the axis, while minor septa extend only a very short distance into the tabularium (P1.27, figs.1—4). Dilation of septa is fusiform, and in some corallites is extreme, with the periphery of the tabularium completely oc- cupied by dilated septa (P1.27, fig.2), while others are little dilated, occupying approximately /, to 7% of this perimeter, averaging close to /, for the species. Mature corallites normally approximate 5.5 to 6.5 mm in total diameter, and tabularial diameters range from a colony mean of 4.1 in the smallest to 4.6 mm in the largest of the nine colonies studied from the type area (Text- fig. 38). In these same colonies, the mean number of septa ranges from 33.0 to 35.1. Colonies collected from the Nora Springs area to as far south as Cooper’s Bend on the Shell Rock River are homogeneous in size and number of septa. In longitudinal section the tabularium has an axial row of flat-topped, cap-like tabulae and a periaxial row of sagging partial tabulae (PI1.28, fig.2). This is typical of individuals with long, straight septa reaching al- most, but not quite to the corallite axis. Where septa are shorter, or in corallites in which periodic differ- ences in growth are seen, an irregular tabularium is developed, with incomplete tabulae, and with no axial series developed (P1.28, fig.4). The dissepimentarium is generally narrow, although this is variable. Where the dissepimentarium is narrow, there may be as few as one row of dissepiments. This single row is then composed of bulbous dissepiments, which may reach the epithecal wall and appear flattish in their peripheral portion. This form resembles that labeled “‘peneckielloid’”’ by Hill (1981, p. F26, here shown in P1.28, fig.2). Where the dissepimentarium is broad, generally two to four rows of small bulbous dissepiments are present, and these are more inclined axially at and near the boundary between the tabular- ium and dissepimentarium (P1.28, fig.4). In several colonies the innermost row of dissepiments was coated by a layer of stereome, thus marking the inner bound- ary of the dissepimentarium. The dissepimentarium is generally wider when budding is taking place, as buds » ' 1 ' 1 scthsasecthe acid] ' ' ' 1 t <-~----------4 ' ' ' ' roboscodhacand| ' ' 1 1 1 Sates roses Colony Mean Number of Septa ie es Gee ' r\S H aay ----4----- ~4--a-t 32}----4 ease aa === paratype - D. floydense — T T T Le) @+----- olony Mean Diameter of Tabularium - mm Text-figure 38.—Disphyllum floydense from the uppermost beds of the Mason City Member, colony mean diameter of tabularium (in mm) plotted versus the colony mean number of total septa. The colonies from the type area, near Nora Springs south to Cooper’s Bend,are uniform in their size and number of septa (including the paratype, as marked on the graph). Colonies from farther south, the Maxson Quarry at Marble Rock, Iowa, are markedly larger and more variable in numbers of their septa, but fit into the species in all other criteria. arise from its outer portion. Then, six or seven rows of dissepiments may be present. Septal structure is typical for the family, with mon- acanth septal trabeculae that are inclined adaxially. The angle the monacanths make with the epithecal wall is 40° and this angle increases slightly near the inner dissepimentarium as the monacanths flex inward (P1.27, fig.5). The trabeculae in this species of Dis- phyllum are large and rather feathery in appearance, as is common in the Disphyllidae. They become slight- ly larger in some corallites, which then have a knobby appearance in transverse section. This “‘carinate”’ con- dition (P1.27, fig.4) is never uniformly developed in corallites of this species. Type specimens.—Holotype SUI 2001, paratypes SUI 364, 753, and 2003, and USNM 71029, UCM 1477. Discussion.—In addition to abundant colonies noted in the type area of the species (from Nora Springs to Cooper’s Bend), four additional corals have been col- lected from Maxson’s Quarry at Marble Rock (Local- ity 24, Appendix), far to the south of the southernmost occurrences in the type area. The species is homoge- neous near Nora Springs, displaying little tendency to develop larger corallites. The four colony sample from Marble Rock (Maxson’s Quarry) contains one very large form, with a mean diameter of 9.9 mm for nine corallites, and 43 as the mean number of septa (Text- fig. 38); a second large-diameter colony, with mean DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 61 diameter of 10.7 mm and mean number of septa of 41.7 for five corallites, and two other colonies which are a more normal size for the species, with mean di- ameters of 8.4 and 6.4 mm, and 36.3 and 43.6 mean septa. The very large corallites in the two colonies are larger than for any of those collected near Nora Springs, and the remaining colonies from Marble Rock are nearly intermediate in size to those in the type area. The corallites are like those of Disphyllum floydense from the type area in every other way but size and number of septa in the few large corallites (P1.28, fig.3). In longitudinal section, the specimens from the southern area also show the common development of a row of large to very large dissepiments in the pe- ripheral portion of the dissepimentarium (P1.28, fig.4). These dissepiments are not as uniform in size, nor is the outermost row as uniform in development or as well-differentiated from other, more inclined dissepi- ments, as are those of D. conjugens n. sp., or D. iow- ense, both described below. Nevertheless, there ap- pears to be a relationship between these three species, the two from the upper Mason City Member, the other from the Nora Member. Disphyllum fasciculum (Meek, 1877) is close to D. floydense in appearance, with its long, straight major septa, fusiform septal dilation, and narrow tabularium. Stumm (1940, p. 62) noted that D. fasciculum has cor- allite diameters of 5 mm and septal numbers of 34 to 36, thus, with respect to these parameters, the species are very similar. Stumm also noted that the minor septa are extremely short, ““never extending more than | mm from the periphery” (1940, p. 63). On the same page he also said that the species is characterized by a single row of dissepiments in the narrow dissepimentarium, which can sometimes be the case in some corallites in D. floydense. The specimen labeled Disphyllum fasci- culum illustrated by McLean and Sorauf (1989, p. 392) from the Twin Falls Formation of western Canada is very close in the appearance of its septal dilation, dis- sepimentarium, and tabularial configuration to D. floy- dense, but the size is larger, with corallite diameters from 9 to 11 mm (measured from photographs), and with septal numbers ranging from 38 to 40, which re- semble the largest specimen collected from Maxson’s Quarry as discussed above, and suggests that the two species are very closely related (or perhaps should not be separated). Disphyllum floydensis resembles the Frasnian spe- cies D. caespitosum (as illustrated in Sorauf, 1987, fig. 7.1) in that both have long septa, both have a well- differentiated external row of bulbous dissepiments, and both have large septal trabeculae. Septal dilation in D. floydensis is much greater than in the New York specimens, however, and in fact, is greater than in oth- er North American species with long septa, except for D. densum (Smith, 1945, p. 22). Disphyllum densum, when restudied, may be found to be a junior synonym of D. floydensis. Occurrence.—Disphyllum floydensis was reported by Belanski (1928, pp. 344, 346) from the uppermost “soft, yellow, argillaceous limestone” of the Mason City Member at its type section, and from the type section of the Rock Grove Member. In his collection, there is also a specimen from “‘Belanski’s Quarry” in Nora Springs, near the old mill dam. The Nora Dam locality yielded numerous specimens (Locality 8, Ap- pendix), while a few colonies were collected at Coo- per’s Bend on the Shell Rock River north of Rockford, Iowa (Locality 19) and from Maxson’s Quarry near Marble Rock (Locality 24). In each case, the occur- rence of this species was from the uppermost beds of the Mason City Member. Disphyllum conjugans, new species Plate 1, figure 5; Plate 28, figures 5—7; Plate 29, figures 1,2 Diagnosis.—Small diameter species of the genus with long major septa nearly reaching to axis of cor- allites, with long minor septa, about Y, length of major, and extending into tabularium. Heavy septal dilation in dissepimentarium, with single row of uniformly large flattish but globular dissepiments coated with stereome and with two to four additional rows of in- clined dissepiments interior to peripheral row. Tabulae differentiated into uniform cap-like, flat-topped axial row and sagging periaxial rows. Description.—D. conjugans generally occurs as small colonies, but of four samples available, three were of broken and/or stromatoporoid coated corallites in the Nora biostromes, so that it is not possible to give colony mean dimensions. In transverse section, these corals are marked by long major and long minor septa. The major septa reach to, or almost to, the corallite axis, and some join laterally. Major septa are usually greatly dilated in the inner dissepimentarium, and may maintain their max- imum width to the epithecal wall or thin somewhat in the outer dissepimentarium (P1.28, figs.5,6). The major septa thin rapidly in the tabularium and are straight, not swirled in the axial area. Minor septa are long, generally reaching /, as far as major septa into the tabularium. Corallites are large, ranging up to 8 mm in outer diameter with 34 to 43 septa. In three speci- mens, corallite diameters ranged from 5.7 to 8.0 mm, with a mean of 6.8 for nine corallites and septa num- bered from 34 to 36 with a colony mean of 35.8 in the first specimen; diameters ranged from 5.8 to 7.5 62 BULLETIN 355 mm in seven corallites, with a mean of 6.6 mm, and with septa ranging from 36 to 38, with a mean of 36.7 in the second specimen. In the third and largest colony, diameters ranged from 5.6 to 7.8 mm, with a mean of 6.8 mm for six corallites, while septa numbered from 40 to 42, with a mean of 40.7. These samples are dis- cussed as three colonies, but in reality, since corals are fragmented and loose in matrix, one cannot prove that only three colonies are involved. Each sample, how- ever, seems to be internally consistent in size and num- ber of septa. Thus, the species has medium large cor- allites, with a correspondingly large number of septa. There is a solid wall of dilated septa and biogenic ster- eome surrounding the tabularium, and the species is distinctive. In transverse section a single row of large dissepiments is also seen in an oblique portion of the peripheral part of the dissepimentarium (PI1.28, fig.5). In longitudinal section, one of the most distinctive features of this species is the row of large, flattened, globular dissepiments at the periphery of corallites (P1.29, fig.2). Dissepiments in this row are thicker- walled than other dissepiments, are considerably larg- er, and are stacked in a uniform row. Thinner-walled, inclined globular dissepiments are present inside this single row, occurring in one to four rows lining the margins of the tabularium. Ordinarily, the species has only one or two rows of these internal dissepiments. Tabulae are differentiated into axial and periaxial rows, with axial tabulae being flat-topped, cap-like structures accompanied by uniformly sagging periaxial tabulae. This configuration is similar to that in many species with long septa in this family, and occurs in several genera. Septal trabeculae are flat, lath-like monacanths which make a considerable angle to the outer wall. In one specimen an angle of 60° from the vertical was measured, and trabeculae generally bend inward to ap- proach horizontality in the innermost dissepimentar- ium. Type Specimens.—Holotype SUI 1625, paratypes SUI 1624, 1376. Discussion.—This is a distinctive species of Dis- phyllum based on the extreme development of bulbous and thickened dissepiments at the periphery of a rel- atively broad dissepimentarium. This is apparently coupled with marked septal dilation in the dissepimen- tarlum, especially in its outer part. Where septa are less dilated, there still may be a solid sleeve around the tabularium of the corallites, as stereome is depos- ited on the inner side of these large peripheral dissep- iments. Although these dissepiments are not truly pe- neckielloid, they do indicate a relationship to the other Mason City species, D. floydense, and also to the wide- spread D. fasciculum, known from the Frasnian of western Canada and Peneckiella fascicularis (Soshki- na), from France (Rohart, 1988). The appearance of the lattef strongly suggests that it is a species of Dis- phyllum with strongly differentiated outermost dissep- iments and several additional rows of more axial nor- mal dissepiments that are strongly inclined axially (Rohart, 1988, pl. 35, figs.10,11). The complex of spe- cies with long septa and differentiated, bulging pe- ripheral dissepiments need to be restudied in order to clarify relationships between Disphyllum and Peneck- iella. Corals discussed here came from both the upper and lower biostromes of the Nora Member. Two colonies from the upper biostrome at County Roads Quarry (Locality 14) are approximately the same diameter, with colony means of 37 and 36 septa, while a third colony, from the lower biostrome at Reed Creek (Lo- cality 4), has a colony mean of 41 septa. In other re- spects, all three are closely similar, although one of the colonies (from Locality 14) has greater development of internal dissepiments, with as many as four rows of these inclined dissepiments. Occurrence.—The three colonies available were col- lected from two localities, with the two having some- what smaller diameters being from the upper biostro- me of the Nora Member at the County Roads Quarry (Locality 14, Appendix), while the colony with slight- ly larger corallite diameters was collected from the lower Nora biostrome at Reed Creek (Locality 4). Disphyllum iowensis, new species Plate 1, figure 4; Plate 29, figures 3—9 Diagnosis.—D. iowensis is a large diameter species of the genus with relatively few, short, slender septa, with major septa reaching 7, of the way to the axis and minor septa only ¥, to /; as long as major septa. A narrow dissepimentarium is filled with steeply in- clined, elongate dissepiments, and tabularium with complete tabulae only in axial area. Description.—The four specimens examined are complete colonies; three are small, with only three to four corallites, and the other is larger, with 15 to 17 corallites preserved (although crushed and broken in- ternally). The larger colony has closely packed coral- lites, but none have adopted the prismatic shape char- acteristic of a cerioid colony. In transverse section, diameters range from 9 to 15 mm, and the largest corallite has 44 septa, although 42 is normal. Major septa are relatively short, extending ¥, to 7, of the way from its periphery to the corallite axis. Septa are relatively slender, are dilated to about twice normal width in the dissepimentarium of the smaller colony, but remain slender throughout coral- lites of the larger colony (P1.29, fig.3). Minor septa are very short, restricted to the narrow dissepimentarium, DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 63 with total length only about Y, that of major septa, and they remain slender. Because of the delicacy of the corallites and their slender septa, much breakage oc- curred due to compaction and diagenesis. The inter- section of septa with tabulae indicates that septa do interfere with formation of tabulae, as segments of ta- bulae intersect septa and are straight in the tabularium. In smaller colonies, the outermost part of the tabular- ium and dissepimentarium are characterized by her- ringbone dissepiments (P1.29, fig.7). In longitudinal section, the tabularium has flat or irregular, complete tabulae only in the axial portion of the tabularium. Peripherally the tabularium is filled with disrupted tabulae that remain fragmental between septa. The dissepimentarium has five to six rows of steeply inclined, globose, elongated dissepiments in mature corallites, commonly having large dissepiments close to the epithecal wall. In youthful colonies cor- allites at first have no dissepiments, then one row of bulbous dissepiments adjacent to the wall, and then they add additional internal, inclined dissepiments around the tabularium margin (P1.29, fig.6). Type Specimens.—Holotype SUI 541, paratypes SUI 1509, 1626 and 1756. Discussion.—Disphyllum iowense belongs to the group of species that are marked by the presence of bulbous peripheral dissepiments (as are D. floydense and D. conjugans discussed above). It is also charac- terized by its large septal trabeculae which can be swollen, giving it a carinate-like appearance, as com- mon in many species of Hexagonaria, and marked septal dilation in the dissepimentarium. Septa are vari- able in length, but in three of the four colonies studied here a wide area remains open in the axial part of the tabularium. D. iowense resembles D. fasciculum (Meek, 1877) in its peripheral dissepiments, although the latter (as illustrated by McLean and Sorauf, 1989, P1.2, figs 6,7) has a smaller diameter and contains fewer septa than does the Iowa species. D. fasciculum is a widespread North American species which probably has numerous synomyms, but at present it is not known exactly how widespread or how many species should be regarded as its synonyms. The Iowa species also has a resem- blance to D. caespitosum that is common in European Frasnian strata in that the latter likewise has peripheral bulbous dissepiments. As illustrated by Rozkowska and Federowski (1972, p. 317), D. caespitosum con- tains a significantly larger number of normal, axially inclined dissepiments. Other species with peripheral bulbous dissepiments are D. rugosum, D. kostetskae and D. fascicularis (Soshkina), all of which have been recognized in Frasnian rocks of Belgium (Tsien, 1970), with the latter two first described from Russia (Sos- kina, 1949, 1952). D. iowensis is differentiated from these three species either by degree of septal dilation or because of abundance of dissepiments. Occurrence.—All specimens of D. iowense are from the top feet of the Mason City Member, the holotype collected at Baumgardner’s Mill (Locality 17, Appen- dix), the paratypes at Belanski’s locality 38, which is an abandoned quarry in the southern part of Nora Springs (Locality 11, Appendix). Genus HEXAGONARIA Giirich, 1896 Hexagonaria Girich, 1896, p. 171; Hill, 1956, p. F280; Sorauf, 1967, p. 24; Pickett, 1967, p. 25; Birenheide, 1969a, p. 41; Tsien, 1977, p. 208; Birenheide, 1978, p. 87; Hill, 1981, p. F275; Rohart and Semenoff-Tian-Chansky, 1981, p. 4; Rohart, 1988, p. 267; Sorauf, 1988, p. 168; Wrzolek, 1992, p. 237; Sorauf, 1994, p. 332. Argutastrea Crickmay, 1960, p. 10; Hill, 1981, p. F266. Pseudohexagonaria Kramer, 1982, p. 654. ?Cystihexagonaria Rohart, 1988, p. 273. not Pseudohexagonaria Coen-Aubert and Lutte, 1990, p. 23. not Argutastrea Coen-Aubert and Lutte, 1990, p. 20. Type Species.—Cyathophyllum hexagonum Gold- fuss, 1826, by subsequent designation (Lang et al., 1940, p. 69). Diagnosis.—Cerioid colonial corals of the Disphyl- lidae, with clear differentiation of the tabularium and dissepimentarium, thus, also the calicinal platform and axial pit. Long major septa extend well into the ta- bularium although shorter minor septa do not, and sep- tal dilation is spindle-shaped, with maximum dilation in the inner dissepimentarium. Interference of (usual- ly) long septa with tabulae commonly, but not always, results in development of axial and periaxial rows of tabulae. Septal monacanth trabeculae of disphyllid, lath-like type show sharp boundaries with one another in longitudinal view. The dissepimentarium contains numerous globose dissepiments (generally five to ten per row). Where dissepimentarium is wide, outer dis- sepiments approach horizontality, but inner dissepi- ments are always steeply inclined towards the corallite axis. Septal trabeculae seen in longitudinal section form a structure that reflects the orientation of dissep- iments; thus are perpendicular to calicinal surfaces. As a result they form either a uniformly inclined cluster of trabeculae or a splay of trabeculae with axial incli- nation that increases to the innermost part of the dis- sepimentarium where bending occurs. Reflexing of calicinal platform and rows of dissepiments can result in the formation of upwardly bowed rows of dissepi- ments and accompanying upward divergence of septal trabeculae. Discussion.—Hexagonaria is a common and wide- spread genus, and has been described or reported by numerous authors from many horizons in many parts of the world. The synonymy given above is not com- 64 BULLETIN 355 prehensive; the reader is referred to Birenheide (1969a) or Hill (1981) for more complete synonomies. The genus has been variously defined; as a result a number of generic names have been proposed for some of the species that should be included within Hexa- gonaria. | have elsewhere (Sorauf, 1994, p. 327) pro- vided an extended discussion of the genus name usage, varying definitions of the genus, various interpreta- tions of the type specimens of Hexagonaria hexagona, as well as the resulting multiplicity of interpretations of the genus, and the effects of this on genus, subfam- ily and family nomenclature for species. Varying di- agnoses for this genus have resulted in a great deal of confusion about some other colonial genera of the Dis- phyllidae. Much of this confusion has resulted from the pres- ence of carinae-like septal structures in the neotype and topotypes of Hexagonaria hexagona from Fras- nian strata in the Refrath area of northwestern Ger- many. Pickett (1967, p. 59) chose a neotype for the species, and his choice has been followed by all sub- sequent workers. This, and other topotypic specimens have septa with laterally expanded septal trabeculae which resemble septal carinae. I have shown (Sorauf, 1994, p. 332) that this expansion is part of the process of septal dilation, and pointed out that not all corallites have this feature fully developed in the type specimen. I concluded that it is an error to exclude colonial dis- phyllid corals lacking such structures from the genus. Wrzolek (1992, p. 237) has also recognized that septal “carination”’ is often weakly or sporadically developed in H. hexagona and recognized a separate subspecies for a population of the species from the Holy Cross Mountains of Poland. Hill had characterized the genus (and its subfamily) as having “‘typically closely cari- nate septa with predominantly yardarm carinae”’ (1981, p. F275). In so doing, she followed Birenheide (1978, p. 95), whose opinion was that the genus name should be exclusively applied to cerioid coral colonies with yardarm carinae. I regard the “‘carinae”’ seen in the type species of the genus, and other closely related species, as dissimilar to yardarm carinae as developed in Heliophyllum and related genera (Sorauf, 1994, p. 326). Part of my understanding of this variable devel- opment of septal structures is based on study of the Iowa species Hexagonaria bassleri and H. oweni, both of which have variable dilation of septa trabeculae and variable development of yardarm-like septal structures. The genus name Hexagonaria is used here to in- clude species with typically dilated septa which may or may not bear weakly or strongly developed carinae- like septal structures. More briefly stated, it is used to include generalized cerioid colonial corals of the fam- ily Disphyllidae. The genera Pseudohexagonaria Kri- mer, 1982 and Argutastrea Crickmay, 1960 are syn- onyms ‘in that they were first defined as pertaining to Hexagonaria-like corals lacking carinae. These two genera, as redefined by Coen-Aubert and Lutte (1990, pp. 20,23) retain their usefulness. Neither pertains to the Frasnian species in Iowa, which are rather central to the genus concept of Hexagonaria, as typified by H. hexagona. The genus Cystihexagonaria Rohart, 1988, proposed for Hexagonaria-like corals with lim- ited development of a lonsdaleoid dissepimentarium, may be of use in dealing with some species, but has no applicability to species from Iowa. Hexagonaria bassleri (Webster and Fenton, in Fenton and Fenton, 1924) Plate 3, figure 7; Plate 30, figures 1—6; Plate 31, figures 1-6; Plate 32, figures 1—5; Plate 33, figure 1 Acervularia bassleri Webster and Fenton, in Fenton and Fenton, 1924, p. 58, Pl. 13, fig. 2, Pl. 14, figs. 4-6. Acervularia bassleri depressa Webster and Fenton, in Fenton and Fenton, 1924, p. 60, Pl. 12, figs. 1,2. Acervularia bassleri magna Webster and Fenton, in Fenton and Fen- ton, 1924, p. 61, Pl. 14, fig. 6. Prismatophyllum cf. P. magnum Smith, 1945, p. 47, Pl. 15, figs. 1— 4, Pl. 18, fig. 2. Prismatophyllum reticulatum Smith, 1945, p. 48, Pl. 16, figs. 1-3, Pl. 18, fig. 4; McLean, 1984, p. 472. Hexagonaria bassleri McLean, 1984, p.472; McLean and Sorauf, 1989, p. 394, Pl. 2, figs. 1,2; Sorauf, 1994, p. 332, Pl. 2, figs. A- EF Pl. 3, figs. A-D. Hexagonaria magna McLean, 1984, p. 472. Hexagonaria bassleri magna McLean and Sorauf, 1989, p. 383 Diagnosis.—Species of Hexagonaria with wide range of corallite size and septa numbering from 30 to 40, clearly differentiated into major and minor. It re- sembles the type species of the genus, H. hexagona, in shape of septa in transverse section and occasional development of swollen septal trabeculae and resultant carinae-like structures. Tabularium displays both flat- topped axial row of tabulae and periaxial sagging ta- bulae; dissepimentarium filled with small dissepi- ments. Description.—H. bassleri occurs in flattened cerioid colonies with dimensions generally approaching 20 cm in diameter and 10 cm in thickness. Corallites show a great range in size, with the colony mean diameter of tabularium varying from 2.9 to 7 mm, and the colony mean number of septa varying from 34 to 55. These numbers are deceptive, however, because the core group of H. bassleri varies only from 4 to 6.5 mm in mean colony tabularium diameter and from 34 to 45 in colony mean septa (Text-fig. 39). The larger form (P1.32, fig.2) is sufficiently different to warrant the use of the subspecies name H. bassleri magna, proposed by Webster and Fenton, and the single small specimen is the holotype of a small subspecies named H. bas- DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 65 a = T SS T T T T H H H H H H H H ' ' ' ' ' 1 t 1 1 ( t 1 ' ' t t ! ' ' 1 ' ' t ' ' ' ' ' ' t 1 ' ' ' f i] ' ' i] t ' t t aoc |i cane eae nt eee te Hi eae | a ' ' vo ' ' ' ' ' BS ' 1 ' ' H S ' H H H t \ ' RE Pesan eae a ares eae os —————9 ae pianaeny E ' ' ' ' ' ' ' ' 5 z \ ' \ ' ' ‘| | H. bassleri magna c 1 ' ' ' 1 5 49+ 1 holotype | +---_4----- ———— +--==4-===- a = Tas SME eke te s ' ' ' \ H H é H ' \ ' 35 ----4 —--t----4d----- 4----4----- Waimea \—_——<—= ! . . ' 1 ' ' ! H. bassleri bassleri ! \ ' 1 H i T T i 1 ' i ' ' ' ' 30 a — }———+ 2.5 3 a5 JS SS SSS SG GS as Colony Mean Diameter of Tabularium - mm Text-figure 39.—Hexagonaria bassleri from the upper part of the Owen Member, the so-called ““Acervularia zone’, colony mean di- ameter of tabularium (in mm) is here plotted versus the colony mean for the total number of septa. The typical subspecies is smaller, with fewer septa than the larger subspecies H. bassleri magna, recognized by Webster and Fenton in 1924. sleri depressa by Webster and Fenton, but not recog- nized here. In transverse section two phenotypes are noted. The first is represented by the holotype and by the majority of colonies in the sample. Here, septa are thin in the outer dissepimentarium and are dilated, with typical spindle-shaped dilation in the inner dissepimentarium. Major septa then taper to be thin and blade-like, con- tinuing into the tabularium, where they reach nearly to the corallite axis and are deflected to swirl slightly around the small open space at the axis (P1.30, figs.1,6). The diameter of the axial open space is ap- proximately ¥, the tabularium diameter or less. The other form occurring here is seen in one of the para- types and occasionally elsewhere. In these colonies, septa are heavier, and septal dilation is more spear- shaped in the inner dissepimentarium, with the heavy dilation continuing into the outer tabularium (P1.31, fig.4). In fact, the widest part of the septa is in the outer tabularium. The heavy septa commonly have swollen trabeculae in the outer dissepimentarium, and bear structures resembling carinae in some corallites. Some corallites, especially immature ones, have major septa that extend to the axis where they swirl or con- nect irregularly across the axis. In both forms, the inner dissepimentarium is marked by closer spacing of dissepiments, as the section plane cuts more steeply inclined dissepiments that surround the outer tabularium. The outer dissepimentarium has more widely spaced intersections, interseptal spaces can be very large in the outer corners of asymmetrical corallites, and septa may even be somewhat discontin- uous here. This incompleteness of septa and associat- ed(?) large dissepiments may be related to the budding process, as suggested by the location of the areas af- fected (P1.30, fig.2; Pl.32, fig.1). In longitudinal section, all corals of the species have the type of tabularium characteristic of species of Hex- agonaria with long major septa, thus have an axial row of flat-topped, cap-like tabulae and periaxial rows of uniformly downbent tabulae or more rarely, flat or in- clined straight tabulae (P1.30, figs.3,5). This shape of tabularium is characteristic of many species in the Dis- phyllidae. The dissepimentarium is also typical of the family in that it consists of rows of uniformly-sized dissepiments that are steeply inclined next to the ta- bularium, and are flat near the outer wall. Generally there is a rather uniform change of slope from steeply inclined near the tabularium to flat near the wall, but this may vary, and even show some arching as a result of reflexing of the calicinal platform. Septal fine structure is clearly seen in longitudinal sections, and trabeculae are characteristically rather large, well-defined monacanths that are sometimes somewhat swollen and feathery in appearance. The monacanths make a small angle with the outer wall of the corallite, and bend progressively inward to make an angle approaching 45° in the inner dissepimentar- ium, where they commonly flex inward to be almost horizontal in the outer tabularium (PI.31, figs.5,6). Type specimens.—Holotype USNM 78619, para- types USNM 78621, UMMP 8085. H. bassleri de- pressa holotype USNM 78620, paratype UMMP 8084. Discussion.—Numerically, this species dominates the uppermost beds of the Owen Member of the Lime Creek Formation. It is very typical of the genus Hex- agonaria; in fact, I regard it as closely related to Hex- agonaria hexagona (Goldfuss) (see Sorauf, 1994, p. 332). As a species with long septa, it exhibits axial and periaxial rows of tabulae, and very typical spindle- shaped septal dilation is seen in transverse section. In addition, this species of Hexagonaria resembles the type species in that both have characteristic inflation of septal trabeculae as part of the septal dilation pro- cess. H. bassleri shows a range of septal thicknesses, from virtually undilated, through partly dilated with swollen septal trabeculae, to heavy, dilated septa with trabeculae swollen to form “‘carinae” (PI.31, figs.1— 4). Although these swollen septal trabeculae may be legitimate septal carinae, they are not analogous to the yardarm carinae formed in Heliophyllum and other genera, where carinae are formed prior to the infilling of interseptal spaces of the septa and are not part of a process of septal dilation. For this reason, the carinate structures of Hexagonaria are here referred to as “cari- nae”’ or “‘carinae-like structures”. Septal carination, its 66 BULLETIN 355 description, and understanding of its construction and function are vital to the proper evaluation of the genus and the family Disphyllidae (Sorauf, 1994, p. 333). In addition to showing variation in septal dilation and carination, H. bassleri also shows considerable variation in size as measured by diameter of tabular- ium; and number of septa (Text-fig.39). The distribu- tion of colonies by mean size and septal number in- dicates that Webster and Fenton were correct in rec- ognizing a large subspecies of H. bassleri, H. bassleri magna (in Fenton and Fenton, 1924, p. 61). In addition to the holotype, a number of very large diameter col- onies were collected at the Lillibridge Quarry (Local- ity 38, Appendix). This subspecies is described below. Occurring alongside this subspecies with large cor- allites are much more numerous colonies of normal size (Text-fig. 39). These corals were also collected from the same uppermost beds of the Owen Member, at Owen Grove and all other localities where the unit outcrops or is quarried. This normal-sized group in- cludes the holotype; thus I recognize the subspecies, H. bassleri bassleri Webster and Fenton, in Fenton and Fenton, 1924, p. 58. This is the nominate subspecies, as a result of change in rank; there is no change in authorship or date. Webster and Fenton also proposed a subspecies, H. bassleri depressa for colonies of the species with smaller corallites. They emphasized the depth of the calicinal pit, but I consider this feature too much af- fected by growth stage, ecologic conditions and pres- ervation to be a practical taxonomic criterion. The size of corallites in the holotype of the depressa subspecies is indeed small, but not much smaller than in the ho- lotype of the species, and their subspecies paratype (UMMP 8084) has a larger colony mean corallite size than many other coralla of the species. This subspecies is here regarded as a synonym of the nominate sub- species. H. bassleri resembles a number of described Fras- nian species of the genus from Belgium and the Bou- lonnais Region of north France. These all are charac- terized by long major septa that reach to, or almost to, the corallite axis, have spindle-shaped septal dilation, and thin septa in the dissepimentarium with numerous globular dissepiments occurring in rows steeply in- clined at the boundary between the tabularium and dis- sepimentarium, and which have axial and peri-axial rows of tabulae. This list includes the following spe- cies: H. marmini (Rohart, 1988, p. 268) and H. mae (Rohart, 1988, p. 270) from the Frasnian of north France; H. buxutiensis (Tsien, 1977, p. 213), H. mae and H. gamboni (Tsien, 1977, p. 215; Coen-Aubert, 1979, p. 11), and H. mirabilis (Coen-Aubert, 1979, p. 6) from the Frasnian strata of Belgium. The relation- ships between the H. bassleri group in lowa and west- ern Cafhada to these numerous species in Europe re- main to be established. H. bassleri is regarded as senior synonyn of H. re- ticulata (Smith) by McLean (1984, p. 472). Smith (1945, p. 48) described Prismatophyllum reticulatum from Frasnian beds in the Northwest Territories of Canada. I have not seen the types of this species. Occurrence.—H. bassleri was listed by Fenton and Fenton (1924, p. 59) as present throughout the Owen Member, and especially common in the uppermost beds, their ““Acervularia zone’’. I collected this species at both Owen Grove and Owen Grove West (Localities 25 and 26, Appendix), and at quarries in the Owen Member at Rockwell, Iowa (Locality 36) and at Lil- libridge Farm (Locality 38), and at localities 40, 40A and 41, south of Dumont, Iowa. In all cases but one, the unit containing Hexagonaria bassleri was the up- permost limestone bed of the Owen Member (the “Ac- ervularia zone’ of Fenton and Fenton). At the quarry on the Carrollus Farm (Locality 41), a single specimen of H. bassleri was collected from low in the Owen Member, approximately 2 m above the basal lime- stones containing branching stromatoporoids. Thus, the local range zone for this species extends through most of the Owen Member. Hexagonaria bassleri bassleri (Webster and Fenton, in Fenton and Fenton, 1924) Plate 3, figure 7; Plate, 30, figures 1—6; Plate 31, figures 1—6; Plate 32, figure 1 Acervularia bassleri Webster and Fenton, in Fenton and Fenton, 1924, p. 58, Pl. 13, fig. 2, Pl. 14, figs. 4,5. Acervularia bassleri depressa Webster and Fenton, in Fenton and Fenton, 1924, p. 60, Pl. 12, figs. 1,2. Hexagonaria bassleri bassleri McLean and Sorauf, 1989, p. 388, PI. 2, figs. 1,2. Diagnosis.—As for the species, excluding large di- ameter subspecies described under H. bassleri magna. Type Specimens.—As for the species, holotype USNM 78619, paratypes USNM 78621, UMMP 8085. Discussion.—Although Webster and Fenton did not formally propose a nominate subspecies for Acervu- laria bassleri, but did propose the subspecies Acer- vularia bassleri magna, they in essence, created the subspecies A. bassleri bassleri by removal of those coralla characterized by large corallite sizes. I accept both as legitimate subspecies of Hexagonaria bassleri. The subspecies Acervularia bassleri depressa, pro- posed by Webster and Fenton, in Fenton and Fenton, 1924, p. 60, is properly regarded as part of Hexagon- aria bassleri bassleri. Occurrence.—As noted above, this subspecies is present at all outcrops yielding the species. Only those DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 67 localities listed under H. bassleri magna contain the other subspecies. Hexagonaria bassleri magna (Webster and Fenton, in Fenton and Fenton, 1924) Plate 32, figures 2—5; Plate 33, figure 1 Acervularia bassleri magna Webster and Fenton, in Fenton and Fen- ton, 1924, p. 61, Pl. 14, fig. 6. Hexagonaria bassleri magna McLean and Sorauf, 1989, p. 383. Hexagonaria magna McLean, 1984, p. 472. Prismatophyllum ct. P. magnum Smith, 1945, p. 47, Pl. 15, figs. 1— 4, Pl. 18, fig. 2. Diagnosis.—Hexagonaria bassleri with large cor- allites, large diameter of tabularium, and numerous septa. Description.—Coralla of this subspecies are not no- ticeably larger than others of the species, but contain fewer, larger corallites than the nominate subspecies. Corallites of H. bassleri magna are large, with their diameter of tabularium varying from 6 to 7 mm, with a mean of 6.5 mm for the six colonies studied (Text- fig.39). Their septa are more numerous than others in the species, with colony means of from 49 to 55, with a mean of 52. In other respects the subspecies is sim- ilar to others included in H. bassleri. Type Specimen.—Holotype USNM 78637. Discussion.—H. bassleri magna, considered here as a valid subspecies, has been recognized in western Canada (Smith, 1945; McLean, 1984; McLean and So- rauf, 1989). It has been regarded as a species by Smith and a subspecies of H. bassleri by other authors. In the Iowa fauna this form with large corallites appears to me to be clearly separable only on the basis of cor- allite size, and I do not consider it a separate species. This taxon is similar to Frasnian species of western Europe that have long septa and large corallites. In size of corallites, it resembles H. hexagona (Goldfuss, 1826), but contains many more septa than does this German form (Sorauf, 1994). Occurrence.—The holotype was collected from Owen Grove, from the uppermost beds of the Owen Member, from the ““Acervularia zone”’ of Fenton and Fenton (1924, p. 8). Further specimens were collected by me from these same beds at the Lillibridge Quarry (Locality 38, Appendix). Hexagonaria oweni (Belanski, 1928) Plate 1, figure 7; Plate 33, figures 2—5; Plate 34, figures 1,2 Prismatophyllum oweni Belanski, 1928, p. 174, Pl. 1, fig. 2. Diagnosis.—Species of Hexagonaria with medium to small corallites characterized by long major septa that are very thin in the tabularium, with small open axial space. Tabularial diameter has a small range (4 ssiteeue Hexagonaria oweni — 4.6 a > ee ee eee ee eee i) _ Colony Mean Number of Septa ras Liat 5 Riera eee Oar eT a oS a for) ores 4.4 Colony Mean Diameter of Tabularium - mm Sie Text-figure 40.—Hexagonaria oweni from the upper biostrome of the Nora Member, colony mean diameter of tabularium (in mm) plotted versus the colony mean for total number of septa in each corallite. to 5 mm), and while major septa always dilate, minor septa commonly do not. Occasional “‘carination” of septa occurs in some colonies, but small diameter cor- allites have stout, smooth septa. Description.—H. oweni occurs in flattened, discoid colonies with maximum diameters commonly ap- proaching 20 cm and height approaching 10 cm. Cor- allites are relatively small, and colony means for the tabularial diameter vary from 4 to 5 mm, a narrow range of variation (here for eight colonies), and colony means for the septal number vary from 32 to 40, as diameters increase (Text-fig. 40). The size of tabularial diameter and the number of septa are closely correlat- ed in this species. Septa occur in two orders, and major septa extend into the tabularium as thin, blade-like ex- tensions to the axial area, where a small open space remains with its diameter /, to /, of the tabularium. In some colonies, some corallites have long major septa which join at the corallite axis. Septal dilation is marked, especially in major septa, as minor septa can remain undilated. In many colonies, especially those with small corallites, septa are stout in the outer dis- sepimentarium, have marked dilation in the inner dis- sepimentarium and rapidly taper to thin blades in the tabularium. Septal trabeculae are expanded to form ‘“‘carinae-like’’ structures in some corallites (PI1.34, fig.2). In the colony with smallest corallites, the short, stout septa do not bear “‘carinae”’. Here, intercorallite walls have a zigzag path in transverse section, caused by the position of septa being offset between neigh- boring corallites (resulting in the zigzag path). In col- onies with larger corallites, septa are thin in the outer 68 BULLETIN 355 dissepimentarium and corallites have straight intercor- allite walls. In longitudinal section the tabularium has an axial series of flat-topped, cap-like tabulae and a periaxial row of sagging tabulae, or irregular, complete tabulae. In those colonies with short major septa, tabulae tend to be more complete and differentiation into axial and periaxial rows disappears (P1.34, fig.1). The dissepi- mentarium is filled with five or more rows of dissep- iments, which vary in size, from small and globular to more elongate and larger. Rows of dissepiments tilt axially as they progress into the inner dissepimentar- ium, and the innermost rows are tilted nearly 90°, lin- ing the tabularium. Septal trabeculae are well-differentiated, large mon- acanths, as is typical for the genus. Trabeculae form a small angle (<30°) with the corallite wall and bend inward, and then flex inward to near horizontal at the outer boundary of the tabularium (PI1.34, fig.1). Type Specimens.—Holotype SUI 471, paratypes SUI 134, 1522, USNM 71041, UCM 1474 (last spec- imen not seen). Discussion.—This species shows its close relation- ship to H. hexagona by its long major septa, axial and periaxial rows of tabulae, occasional ‘‘carination”’, and broad, well-differentiated monacanthine septal trabec- ulae which flex axially in the innermost dissepimen- tarium. H. hexagona has corallites that are much larger and have many more septa than does H. oweni; in addition, topotype colonies of H. hexagona all have heavily dilated septa and well-developed *‘carinae”’ lo- cally. H. oweni resembles H. bassleri of the Lime Creek Formation in these same characters, but has fewer sep- ta, and in small corallites has shorter septa that are stouter in the outer dissepimentarium. H. bassleri also can become extremely large (as H. bassleri magna). This species has a general resemblance to several Hexagonaria species from Frasnian strata of western Europe. Relationships and species boundaries have not yet been determined for this complex group. Occurrence.—H. oweni is the typical Nora species of this genus. The types established by Belanski all came from the **Prismatophyllum zonule”’ of Belanski, at Rudd, Iowa, which he reported was the lower stro- matoporoidal biostrome of the Nora (1927, p. 352). The specimens collected by me are exclusively from the basal meter of the upper Nora biostrome, with a few specimens coming from the McEachron Quarry, south of Portland (Locality 13, Appendix), and with approximately 30 specimens collected from the basal beds of the upper Nora biostrome at the locality south of Rockford, Iowa (Locality 21). Hexagonaria inequalis (Hall and Whitfield, 1873) Platé 2, figure 5; Plate 34, figures 3-5; Plate 35, figures 1—5; Plate 36, figures 1—4 Acervularia inequalis Hall and Whitfield, 1873, p. 233, Pl. 9, figs. 11, 12; Clarke, 1903, p. 34; Fenton and Fenton, 1924, p. 56, Pl. 14, figs. 7,8. Acervularia whitfieldi Fenton and Fenton, 1924, p. 57, Pl. 14, figs. 1-3. Diagnosis.—Variable species of Hexagonaria with small corallites and marked septal dilation. Septa in two orders with major septa reaching to axis of cor- allites where they meet or join. Mean diameter of ta- bularia varying within a broad spectrum of from ap- proximately 2.5 to nearly 4 mm, with small corallites having small diameters, narrow dissepimentaria and short, stout septa, sometimes with slightly zigzag wall between corallites. Colonies with larger corallites have larger diameter of tabularium, broader dissepimentaria and septa that are elongate and thin in the outer dis- sepimentarium, abutting against straight intercorallite walls. All colonies studied have similar appearance in longitudinal section, with tabulae in axial and periaxial rows. Description.—Hexagonaria inequalis is a variable species of the genus, having two end morphotypes, the result of population variation, that are quite different in appearance, resulting in taxonomic confusion. Col- onies are cerioid, and generally somewhat small and flattened. The holotype is a colony 13 cm in diameter with a maximum height of 4 cm. Others range to di- ameters of 20 to 25 cm and heights of 6 or 7 cm and are generally both the size and the shape of thick plates. The calices are characterized by an incised, ta- bularial pit 2.5 mm deep and a flat peripheral platform, occasionally with an everted area in the inner disse- pimentarium. Corallites are generally small, and in the 18 coralla studied, the colony mean diameter of tabularium varies from 3 to 4 mm, and the mean number of septa ranges from 27 to 32 for the same colonies (Text-fig. 41). All of those colonies with very small corallite diameters are characterized by few septa. Within this population are seen two gradational morphotypes, one with crowded corallites, narrow dissepimentaria, small ta- bularia and very stout, thick septa, and a second with less crowded, larger corallites, broader dissepimentar- ia, larger tabularia and septa that are thinner and more elongate in the outer dissepimentarium. The two are intergradational. The lectotype of H. inequalis, from Hackberry Grove (Locality 28, Appendix), is charac- teristic of the first morphology, and in fact, has the smallest mean tabularium diameter of all the speci- mens studied (2.5 mm). Corallites in this colony are closely packed, with septa that are short and very stout DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 69 2 a =2=+ atti ' 1 1 H ‘ it = al lr Oo] (oT || s H ; ' = 1 28) ii i a |. T ' 1 ' ' 1 Pe at ath i) 9 i) 1 1 ' 1 ' f Re at ers 09005 oes a GP SE SESS; SSseSy a ' ' 1 3 ' ' H Se cO aan E fae aa orcs ine a i povamcatie| Skea 3 ie: oS) ey ae ae aa meer | ern 2 i eagehe =| é ices ete ee Aes poli = H i 1 SeeB Si oWaseaingeae an sl praee re oe aT 3 H t t OO 28+---\.-4-------+------4><*---- t------ 4-------+------4 Hexagonaria inequalis pe eee [Feria ree | 27. 26 28 30 32 34 36 38 40 Colony Mean Diameter of Tabularium - mm Text-figure 41.—Hexagonaria inequalis from the “rusty bed” of the Cerro Gordo Member, colony mean diameter of tabularium (in mm) plotted versus the colony mean for total number of septa in each corallite. The small diameter holotype of H. inequalis is here indicated, as well as that of Hexagonaria whitfieldi, here regarded as a junior synonym. in the outer dissepimentarium, but with major septa that extend to corallite axes and either join or leave an extremely small open axial space (P1.34, fig.3). The thick septa are dilated somewhat and make an almost solid ring around the outer tabularium by addition of stereome coating of the inner flank of the dissepimen- tarium. Intercorallite walls either are straight where stout septa of neighboring individuals are opposed, or slightly wavy where septa are offset in neighboring corallites. In many corallites the major septa are dilat- ed by up to 50% in the innermost dissepimentarium; equally thick minor septa are not dilated, but simply retain their thickness throughout the dissepimentarium and tabularium. The second morphotype in this species is one with greater distance between corallite axes and broader dissepimentaria (P1.34, fig.5). Colonies of this type have septa that are thinner in the outer dissepimentar- ium, and intercorallite walls are straight. Septa may have swollen trabeculae in the outer dissepimentarium giving a carinate appearance, and dissepiments are large and globose in this area. Where these thinner septa are at all thickened, there is a resulting broader base at the wall, so that a series of triangular bases is present, buttressing the walls. These also have marked dilation in the inner dissepimentarium, but more spin- dle-shaped dilation, as typical in many species of this genus. Dilation is typically two to three times septal thickness in the outer dissepimentarium. This dilation, along with stereome coating of dissepiments in the in- nermost dissepimentarium, tends to form a heavy ring around the tabularium. All individuals within this species have a similar appearance in longitudinal section, regardless of their appearance in transverse view. The tabularium has a characteristic axial row of flat-topped, cap-like tabulae and periaxial rows of sagging tabulae (P1.36, figs.2,4). The term “‘characteristic’”’ here refers to the common occurrence of this type of tabularium in many Hexa- gonaria species with long septa, including H. hexa- gona. The dissepimentarium is filled with four to eight rows of bulbous dissepiments that can be large in the outer part of the dissepimentarium and also can be slightly everted to reflect a slight reflexing of the cal- icinal platforms. Septal structure is again typical for the genus, with well-defined monacanthine trabeculae making a rela- tively small angle with the intercorallite wall (<30°N) and bending inward to the inner dissepimentarium where the monacanths flex toward the horizontal. This flexing is very characteristic of the species, as is clear- ly shown by Plate 34, figure 4, and Plate 36, figure 2. Type Specimens.—Lectotype, chosen by Clarke, (1903, p. 34), H. inequalis NYSM 3000/1. (Fenton and Fenton referred to several topotypes as ‘‘plesiotypes”’: FMNH 26048 and USNM 78635). Acervularia whit- fieldi holotype is UMMP 5319, paratype FMNH 26055. Discussion.—Recognition of the two forms de- scribed above resulted in a second species being intro- duced in 1924, Acervularia whitfieldi Fenton and Fen- ton (1924, p. 57), for the morphotype with less crowd- ed corallites and thinner septa in the outer dissepimen- tarium. As shown on Text-figure 41, the holotype proposed by the Fentons has a colony mean tabularial diameter of close to 3.5 mm and a correspondingly large mean number of septa (31.2), but these colonies were not thin-sectioned by Fenton and Fenton, with resultant confusion. Their paratype is small and very similar to the lectotype of H. inequalis, with short, thick septa. The Clarke lectotype of Hall and Whit- field’s species was not sectioned until the present study. The specimen of Acervularia inequalis figured in calicinal view by Fenton and Fenton (1924, pl.14), when sectioned, is a corallum with thin septa in the outer dissepimentarium (PI1.35, fig.2), indicating that these authors had difficulty separating their species from that of Hall and Whitfield. The two are regarded here as synonyms. Variation between the two morphotypes in this pop- ulation of Hexagonaria inequalis is seen in Text-figure 41, which shows colony means for septal number plot- ted versus tabularial diameters. Colonies with small corallites are characterized by thicker septa while forms with larger corallites are characterized by thin- ner septa. Hexagonaria inequalis in its thin-septaed morphotype is a very typical species of the genus and 70 BULLETIN 355 resembles H. hexagona. It also resembles H. bassleri of the Owen Member in that both have long major septa that thin in the broad dissepimentarium. H. ine- qualis is characterized by smaller tabularial diameters, and those colonies with extremely small corallites and septa of uniform thickness are easily differentiated from any other species. Occurrence.—H. inequalis was noted by Fenton and Fenton as occurring in the upper part of the Cerro Gordo Member, as does H. whitfieldi. More precisely, they noted both as occurring within the “‘Stromato- porella faunule”’ in the upper part of their “‘Spirifer zone” (1924, pp. 57, 58). Both of these morphotypes, regarded here as a single species, were collected only from a single bed recognized at two sections south of Portland, Iowa (Localities 27 and 27A, Appendix) and at the type section of the Lime Creek Formation (Lo- cality 28), where the species is very abundant, but oc- curs only within a single 0.5 m-thick silty limestone bed (the ‘“‘rusty-weathering”’ bed) that is characterized by abundant specimens of Jowaphyllum, Pachyphyl- lum, Alveolites, and stromatoporoids. It occurs approx- imately 8 m (26 ft.) below the basal beds of the Owen Member. The lectotype and Fenton topotypes of H. inequalis are both labeled as coming from Hackberry Grove (Locality 28 of this study). The holotype of H. whitfieldi was chosen from the Rominger Collection at the University of Michigan and is labeled as being from Cerro Gordo County, lowa, while the paratype is simply labeled as from Rockford, Iowa. I would pre- sume that the locality is the same as all other colonies collected (Hackberry Grove). Family PHILLIPSASTREIDAE Roemer, 1883 A generic framework for the Family Phillipsastrei- dae was outlined by Hill (1981, p. F281): it is here modified with respect to both solitary and colonial cor- als of the family. It is incorrect to use the simple pres- ence or absence of “‘horseshoe dissepiments”’ as a ma- jor criterion for inclusion of genera in this family, or for inclusion of species within one of its genera. Def- inition of the exact meaning of this term, which per- tains to characteristic dissepiments of the phillipsas- treids is not broadly agreed upon. That is, the exact shape, and uniformity of size and shape of horseshoe- shaped dissepiments occurring at the tabularium-dis- sepimentarium border is not clearly defined. Further- more, the degree of distinctness of this row of dissep- iments from other dissepiments is not clearly defined with regards to taxonomic importance. A universal character in genera of this family, however, is the pres- ence of a symmetrical fan of coarse, individually dis- crete, monacanth or rhipidacanth septal trabeculae. The axis of this branching or fanning coincides with the presence of a sleeve of horseshoe-shaped or other upbowed dissepiments that reflect the up-pocketing of polypal flesh to form elevated calicinal skeleton sur- rounding the tabularium. These specialized dissepi- ments, when uniformly developed in a highly arcuate form with their base less than or approaching their maximum width, do indeed resemble horseshoes, and are universally agreed to be “horseshoe dissepi- ments”’. They are commonly coated with skeletal ster- eome, and thus are distinguished from other dissepi- ments by their thickness as well as by their shape. However, this feature is more variable than the pres- ence of divergent (fanning) septal trabeculae and spe- cialists working on this group can more profitably fo- cus on the septal trabeculae than on dissepiments, whether “horseshoes’”’, or “‘specialized’’, or merely differing in their shape from other dissepiments. Within the Phillipsastreidae, Hill (1981) recognized several groups of genera, although she avoided assign- ing genera to subfamilies. It still remains to define gen- era accurately and convincingly prior to subdivision of this complex. Hill (1981, p. F281) also presented the taxonomic history of the family and previously pro- posed subfamilies. Genus PACHYPHYLLUM Milne-Edwards and Haime, 1851 Phillipsastrea d’ Orbigny, 1849, p. 12 (in part); Smith, 1945, p. 36: Rozkowska, 1953, p. 57; Schouppé, 1958, p. 233; Strusz, 1965, p. 564; Sorauf, 1967, p. 22; Pickett, 1967, p. 25; Scrutton, 1968, p. 210; Coen-Aubert, 1973, p. 10; 1974, p. 9; Birenheide, 1978, p. 99; Hill, 1981, p. F281; Coen-Aubert, 1987, p. 46; McLean, 1989, p. 239; 1994a, p. 53. Pachyphyllum Milne-Edwards and Haime, 1850, p.68; 1851, p. 397; Rozkowska, 1953, p. 39; Schouppé, 1958, p. 233; Semenoff-Tian- Chansky, 1961, p. 303; Birenheide, 1978, p. 115; Sorauf, 1978, p. 818; McLean, 1986, p. 444; 1989, p. 240; McLean and Sorauf, 1989 p. 392; McLean, 1994b, p. 78. Medusaephyllum Roemer, 1855, p. 33; Scrutton, 1968, p. 210; So- rauf, 1988, p. 173; McLean and Sorauf, 1989, p.392. Pseudoacervularia Schliiter, 1881, p. 84; Rozkowska, 1953, p. 49; Pickett, 1967, p. 26. Type Species.—Pachyphyllum bouchardi Milne-Ed- wards and Haime 1850, p. 68, from the Upper Devo- nian of Ferques, France. Neotype for this species (Mu- séum Nationale d’ Histoire Naturelle in Paris, No. Z114a) here designated. Diagnosis.—Variable genus of massive corals with thamnasteroid, astraeoid, or aphroid colonies. Species characterized by long septa dilated over specialized dissepiments appearing in longitudinal section as straight to somewhat irregular row of upbowed dissep- iments which most commonly form uniform row of horseshoes. Horseshoe dissepiments are generally thickened by secondary layers of skeletal stereome. Septal trabeculae monacanths to rhipidacanths, in sym- DEVONIAN RUGOSE CORALS OF IOWA: SORAUF Wii metrical fans with axis of fan located over sleeve of horseshoes. Commonly characterized by prominent calicinal necks protruding from external calicinal sur- face, with central depression at tabularium. Discussion.—The specimens illustrated by Milne- Edwards and Haime (1851, pl.7, figs.7,7a,7b) have ap- parently been lost, and I here designate the topotype figured by Semenoff-Tian-Chansky (1961, p. 313, pl.9) as neotype. The nomenclatorial aspects of the genus Pachy- phyllum have been much discussed. After many at- tempts to find an acceptable way to differentiate spe- cies of this genus from those of Phillipsastrea, no con- sensus exists. Species of the two genera have much in common, and without doubt, are very closely related; in fact, they are considered synonyms by many coral workers. In an early study of phillipsastreid corals, Smith (1945, p. 37) made a number of important observa- tions, as follows: there is much variation in morphol- ogy within species then assigned to Phillipsastrea s.1.; horseshoe dissepiments are very well developed in many species, but not in all. Epitheca is generally ab- sent, although traces of it are seen in some coralla. He regarded both Medusaephyllum and Pachyphyllum as synonyms of Phillipsastrea. Rozkowska (1953) dealt extensively with colonial Givetian and Frasnian phillipsastreids, and placed spe- cies with well-developed septal dilation and horseshoe dissepiments in the genus Pachyphyllum, putting pseu- docerioid species with horseshoe dissepiments in Pseudoacervularia. She placed species lacking clearly developed horseshoe dissepiments in Phillipsastrea (1953, p. 57). Schouppé illustrated the holotype of Phillipsastrea hennahi which indicates that it has horseshoe-like dissepiments in the inner dissepimen- tarium (1958, p. 233, pl.5, fig.1). He placed Pachy- phyllum, Medusaephyllum and Pseudoacervularia into synonymy with Phillipsastrea as he defined it. He mis- takenly utilized the name Billingsastraea for those cor- als of the family lacking horseshoe dissepiments (1958, p. 237) and illustrated P. goldfussi as an ex- ample (p. 236, fig.25). Semenoff-Tian-Chansky described in detail a new species of Pachyphyllum, P. chenouensis, from Alge- ria (1961, p. 304) and included an extended description of a specimen of P. bouchardi in the same publication. This topotype of Pachyphyllum bouchardi is here des- ignated neotype for the species. Pachyphyllum bou- chardi, as well as the Algerian corals, has corallites that are large, with a diameter in the neighborhood of 10 mm (1 cm) or somewhat larger (up to 16 mm in the type species). Both species likewise have very well-developed, stereome-thickened horseshoe dissep- iments. In a monograph on the Phillipsastraeidae, Scrutton (1968, pp. 210-212) reviewed both the family and the morphology of its prominent genera. He regarded Pa- chyphyllum, Medusaephyllum, and Pseudoacervularia as synonyms of Phillipsastrea, and placed pseudocer- ioid, astraeoid, thamnasteroid and aphroid corals in the genus, with or without the development of well-de- veloped horseshoe dissepiments at the outer border of the tabularium. Scrutton (1968, p. 231) added to the nomenclature of the massive phillipsastreids by pro- posing the genus Frechastraea for pseudocerioid to astraeoid corals with fans of septal trabeculae but rare or absent horseshoe dissepiments. This is a clearly de- fined group of species that had previously been as- signed to several different genera. Scrutton (1968, p. 212) additionally included cerioid colonies with horse- shoe dissepiments in Phillipsastrea; it now appears better to put these in Trapezophyllum as redefined by Hill (1981, p. F284), and discussed below. In the 1970’s there were a number of definitions of colonial phillipsastreid genera, without developing consensus. Coen-Aubert (1973, p. 10) discovered an important specimen, a rare occurrence of Pachyphyl- lum bouchardi at the base of the upper Frasnian se- quence of the Ardennes of Belgium, although she re- garded it as Phillipsastrea (1973, p. 10). Birenheide (1978), in his treatise on corals of the Devonian of Germany, recognized Phillipsastrea, with the synonym Pseudoacervularia, as containing pseudocerioid, as- traeoid and thamnasterioid colonies. He noted that Phillipsastrea bears distinct calicinal prominences sur- rounding the tabularium, but was of the opinion that there is no sleeve of true horseshoe dissepiments sur- rounding the tabularium in the holotype of P. hennahi (1978, p. 100), and suggested that none of the English phillipsastreids have uniform horseshoe dissepiments. Birenheide utilized two genera for those species with well-developed, thickened, uniform horseshoe dissep- iments, the first being Pachyphyllum (1978, p. 116), for corals with large corallites and axially-inclined dis- sepiments interior to the sleeve of horseshoes. He also figured P. bouchardi from Bad Grund in the Harz Mountains of Germany. Additionally, Birenheide (1978, p. 116) retained the genus Medusaephyllum for colonial species with smaller diameter corallites and well-developed horseshoe dissepiments directly sur- rounding the tabularium. In 1978, I suggested criteria for distinguishing spe- cies of Pachyphyllum from those of Phillipsastraea (1978, p. 819); namely, 1) presence of a uniform row of horseshoe-shaped dissepiments, 2) stereome coating on dilated septa and horseshoe dissepiments, 3) in 72 BULLETIN 355 some species, a small axial structure formed by long major septa, 4) presence of some species with large corallite sizes and numerous septa, 5) tendency toward the development of aphroid colonies and a lack of pseudocerioid colonies, and 6) a tendency to develop flat-sided dilation of septa with discrete rhipidacanth septal trabeculae present, both in septa and extending over the tops of horseshoes. Species with these char- acteristics were placed in the genus Pachyphyllum, and it was emphasized that no single criterion or simple combination of several criteria could be used to cate- gorize species of these two genera. It is possible, how- ever, to recognize individual species (each of which is variable) and equally possible to place species in one genus or the other, even though uncertainties exist about proper placement of some. Hill, in the revised Treatise on Invertebrate Pale- ontology volume on the Rugosa (1981) recognized Phillipsastrea, and placed into synonymy (with a que- ry) the following genera: Pachyphyllum, Medusae- phyllum, and Pseudoacervularia, thus taking a very conservative approach to the taxonomy of the group. She also recognized Frechastraea as a separate genus of phillipsastreids (p. F284). In a series of developments in the 1980’s, nomen- clature shifted again. In a paper on species of phillip- sastreids with large diameter corallites, McLean (1986, p. 445) restricted the use of the name Pachyphyllum to a genus name for species with well-developed horseshoes, etc., as suggested by Sorauf, but included as additional criteria, the tendency to form colonies with few corallites, and a form of budding in which the founder corallite is large and elongate, while buds are relatively few. McLean did not specifically note corallite size as a characteristic, but he only chose large diameter species for inclusion in the genus. This definition is not far from that of Birenheide (1978), but does not mention the presence of internal dissep- iments. He did illustrate specimens with these char- acteristic dissepiments in mature corallites (1986, p. 451), and apparently this feature correlates with large corallite size, both here and in the solitary genus Mac- geea. McLean (1986, p. 445) also here stated that Me- dusaephyllum was an appropriate name, as used by Birenheide for corals with characteristics similar to Pachyphyllum as he defined it, but lacking the “‘bou- chardi growth form’’. Several years later, I also utilized this genus name Medusaephyllum for species previously placed in Pa- chyphyllum, but with the exclusion of those with large diameter corallites, suggesting (1988, p. 173) that use of three generic names was appropriate for astreoid and thamnasterioid phillipsastreids, Phillipsastrea, Pa- chyphyllum and Medusaephyllum. The same approach was used by McLean and Sorauf in their paper on the distribution of Frasnian corals in North America (1989, p. 392). Shortly thereafter, McLean (1989, p. 239) revised his definition of the three genera, using Phillipsastrea to cover all species with horseshoe dis- sepiments and variation ranging from colonies with weak and intermittent development, to those with ‘“‘a continuous pipe completely surrounding the tabular- ium”. He placed Medusaephyllum into synonymy with Phillipsastrea. He did, however, retain Pachyphyllum as the genus name for species with few, large coral- lites. Utilizing corallite size alone is not a satisfactory means of separating species such as P. bouchardi, P. chenoensis, and P. crassicostatum from smaller but similar forms. In the Iowa fauna, the size range of P. crassicostatum overlaps with that of Pachyphyllum woodmani. P. crassicostatum does have rare small col- onies that resemble budded individuals of Macgeea, and are characterized by an elongate protocorallite. This elongated, mature protocorallite can also occur in Pachyphyllum woodmani (P1.2, figs.8—10), thus, the feature is seen in colonies of both large diameter cor- allites, and ones with smaller diameters. McLean (1989, p. 240; 1994a, p. 53) noted again that devel- opment of horseshoe dissepiments is a highly variable feature within some species that he assigned to Phil- lipsastraea, and did not consider the generic separation of this genus and Medusaephyllum as practical on the “basis of horseshoe dissepiment development’. He did not comment on either the scheme of Sorauf (1978), or that of Birenheide (1978), which were not based on this single feature, which has often been judged as highly variable and not practical as the sin- gle basis for differentiation of species or genera. Mc- Lean (1994a, p. 70) also utilized the name Chuanbei- phyllum for totally aphroid phillipsastreids, such as P. vesiculosa from western Canada. No fully aphroid spe- cies are present in the Frasnian faunas of Iowa, thus I have nothing to add to the discussion. McLean (1994b, p- 78) has since reiterated his 1989 definition of Pa- chyphyllum based on colonies having a “‘distinctive growth form”, with few, large corallites and the de- velopment of horseshoe dissepiments adjacent to the tabularium. I do not accept this restriction of the ge- neric definition for two reasons, |) the elongate nature of the founder corallite also occurring within some specimens of Pachyphyllum woodmani, and 2) the overlap in corallite size in Pachyphyllum crassicosta- tum and in P. woodmani. Pachyphyllum crassicosta- tum most commonly has a growth form with many large corallites, and other large diameter species as- signed to this genus all are characterized by the pres- DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 33 ence of normal, sloping dissepiments internal to the horseshoe forms, as proposed by Birenheide (1978). There are recognizable groups of species within the massive colonial phillipsastreids, and to ignore these is potentially to ignore the evolutionary development of these corals and also obscure the biostratigraphic value of them. These groups can be summarized as follows: 1. There is a conservative group of corals which comprises species that do not show marked uniformity in their development of horseshoe dissepiments. Some species may show little differentiation of the inner dis- sepiments, but all have somewhat everted calices, all have fans of septal trabeculae, all have the tendency to have long septa that are dilated at the inner border of the dissepimentarium, and all have a pseudocerioid to thamnasterioid colonial form. All species are vari- able, thus it is an error to use one individual corallite or one colony as the basis for acceptance or rejection of species or genus assignment. This group of species is typified by Phillipsastrea hennahi, itself a highly variable species. Closely related species with pseudo- cerioid colonial form and little or no development of specialized dissepiments, but with fanning septal tra- beculae, are placed in Frechastraea. 2. There is a group of species that are advanced in that they have a complete tube or sleeve of uniform horseshoe-shaped dissepiments and marked septal di- lation. They generally lack internal dissepiments and do not have the pseudocerioid colonial form, rather, they may have an aphroid colonial form, and have cal- icinal prominences around the tabularium. This group of species also generally have relatively small diameter corallites, in the 3-8 mm range. This group of species is typified by Pachyphyllum woodmani. 3. There is another group of advanced species, few- er in number, but distinctive in appearance because of the presence of internal dissepiments inside the sleeve of horseshoe dissepiments and large corallite diameters (in the range of 10-16 mm). These species also tend towards the aphroid colonial form or may have con- fluent septa between corallites. The species Pachy- phyllum bouchardi and P. crassicostatum have the general characteristics of this group. Distribution.—Pachyphyllum has a wide geographic distribution, and is found in many of the major areas of outcrop of Upper Devonian (Frasnian) strata; lowa, western United States and Alaska, western Canada, Germany, France, Russia, Poland, and China. Pachyphyllum minutissimum Webster, 1905 Plate 36, figure 5; Plate 37, figures 1—6; Plate 38, figures 1-6 Pachyphyllum minutissimum Webster 1905, p. 70. Phillipsastrea exigua Lambe, Smith 1945, p. 41, Pl. 21, figs. 3-6; McLean, 1994, p. 63, Pl. 5, figs. 3.4. 1 1 t rT t ' t rT 1 ' i} 1 1 BapsHss==== Teas a 7 i} 1 1 1 Tr 7 1 i} 1 vs 7 ' 1 i 1 1 Colony Mean Number of Septa De) ic) + 1 i \ ' =the tft ' ' ' a MA ee ee Assesses ' Seta PAMInUUSSIMUN? || iammmmn t i] t i =; 1.5 2 2.5 3 3.5 4.5 Colony Mean Diameter of Tabulanium - mm Text-figure 42.—Pachyphyllum minutissimum from the top of the Mason City Member, and Pachyphyllum gregarium from the upper biostrome of the Nora Member, colony mean diameter of tabularium (in mm) plotted versus the colony mean number of total septa. These are two of the abundant species of the genus found in the Shell Rock Formation. The holotypes of both are identified on the graph. ?Phillipsastrea nevadensis Stumm, 1940, p. 66, Pl. 7, fig. 13, Pl. 8, fig. 15; McLean, 1994, p. 62, Pl. 3, figs. 5—7, Pl. 4, figs. 1—6, Pl. 5, figs. 1,2,5—10, Pl. 6, figs. 1—4,7. Diagnosis.—Thamnasterioid species of the genus with small corallite diameter and few septa. Septa typ- ically fusiform, generally greatly dilated over horse- shoe dissepiments to form solid ring around the ta- bularium. Two colony forms are present, one with very short major septa, another with septa reaching to the axis and joining. Septa generally confluent from cor- allite to corallite. Tabulae mostly complete and either flat or composite of flat to inclined or sagging incom- plete tabulae that form a flat base to the calicinal de- pression. Description.—Small compact colonies of this spe- cies have corallites with a small diameter tabularium, colony means varying from 1.5 mm to 2.8 mm., and colony mean septal numbers from 19.3 to 27.5 in 19 specimens (Text-fig. 42). In the type specimen and nu- merous other colonies assigned to this species, major septa are short, leaving a septa-free axial area that is from , to 7% the diameter of the tabularium (P1.36, fig.5). In its most extreme form, this type of colony has corallites in which the major septa extend only slightly into the tabularium. The septa are all dilated, and are spindle-shaped, with maximal dilation in the area of the horseshoe dissepiments, where septa join laterally in a few specimens, but with dilated septa ending as a blunt termination in the tabularium. The major septa are characteristically fat and spindle- shaped in cross-section (PI. 37, fig.1). In one group of colonies assigned to this species, generally those with larger diameters than the holotype, major septa are 74 BULLETIN 355 long and extend to the axis of the corallite, where they join (P1.37, figs.3-5). Where long major septa join at the corallite axis there is no swirling of septa around the axis, rather the septa join in a somewhat pinnate arrangement suggesting order of insertion in the calice, with the first-formed joined across the corallite axis. Septa may be quite heavy in the outer dissepimentar- ium, and generally are about /, their dilated width. Septa in these corallites are confluent with or abutting those of neighboring corallites, except where budding produced young aphroid individuals. The ring of horseshoe dissepiments seen in trans- verse sections is generally heavily coated with ster- eome in P. minutissimum, with a solid ring of dilated septa and stereome-coated horseshoes surrounding the tabularium (P1.38, fig.1). Minor septa do not extend past this ring into the tabularium, and in extreme cases the major septa only just do extend beyond it. The tabularium, seen in longitudinal section, has flattish to slightly arched or sloping, complete to in- complete tabulae (P1.37, fig.2). There are no axial or periaxial rows of tabulae. The completeness of the ta- bulae varies with the size of the tabularium and length of major septa. The smaller the tabularium, and the shorter the major septa, the greater the tendency for tabulae to be complete. The dissepimentarium is marked by uniform horse- shoe dissepiments forming a wall surrounding the ta- bularium (P1.38, figs.4,6). There are no dissepiments inside the horseshoes. The horseshoes are coated with stereome, and in some specimens the coating is as thick as the dissepiments are wide, so that the coating extends over the whole horseshoe rather than only be- ing a coating on the inner and outer flanks of the row. The outer dissepimentarium is characterized by large and irregular dissepiments. In those colonies with the smallest tabularia the outer dissepiments may be al- most as large as the tabulae. Trabecular fans are very tight in this species, and rhipidacanth trabeculae are of small diameter and are packed closely together (P1.38, fig.4). The lateral di- vergence of rhipidacanth trabeculae is clearly seen in transverse sections of greatly dilated septa. The fans are centered on the horseshoe dissepiments, and tra- beculae in the outer dissepimentarium are nearly ver- tical (P1.38, fig.6). Type Specimen.—Holotype USNM 78648. Discussion.—Text-figure 42 illustrates the mean di- ameters of the tabularium in nine colonies of P. min- utissimum, and shows the wide range in size for this species. The collection of colonies from the Nora Dam locality are all towards the large end of the scale, while the two smallest individuals are from the southern part of the geographic range, from Rosedale and from Mar- ble Rock. The Marble Rock corallum has the smallest tabularial diameters (and least variation between them). Study of small-diameter corallites in this colony and others (including the holotype) shows that these smallest corallites likewise have 1) short major septa, 2) the most complete tabulae, 3) the most solid peri- tabular sleeve of dilated septa and stereome, and 4) the greatest confluency of septa between corallites (P1.36, fig.5; P1.37, fig.1). Colonies with larger-diameter cor- allites are most likely to have longer septa which join at the corallite axis (P1I.37, fig.5). Likewise, in these larger forms, dilated septa generally do not form a sol- id ring at the position of the horseshoes. Budding appears to affect corallite morphology in several ways. Young corallites are commonly aphroid, and gradually become more nearly confluent as they mature, and septal dilation is less developed in im- mature forms, becoming more marked with maturity. One colony of P. minutissimum, collected from the Nora Dam population has a very weakly calcified skel- eton, with little or no septal dilation. There is a slight amount of stereome on the horseshoe dissepiments, but none elsewhere. The dissepiments in the outer disse- pimentarium are very large and irregular, the horse- shoe dissepiments are irregular, and there are many fewer complete tabulae than normal for this species. I regard this as pathological. There is uncertainty regarding possible conspecif- icity of P. minutissimum and P. nevadensis (Stumm, 1940). In the specimen figured by Stumm (1940, p. 64), septa are long, extending almost to the axis. Stumm noted that the diameter of the tabularium av- erages 3 mm (p. 66), which is too large for P. minu- tissimum, except for occasional colonies within the Iowa population. The specimen figured by McLean and Sorauf from western Canada (1989, pl.1, figs.8,9) has tabularial diameters in the range of 2.5 mm and mean number of septa that is close to 24. The dilation is not particularly marked in this individual, but septal confluency is well developed. The major septa in many of the corallites in this Canadian corallum do not ex- tend into the tabularium. As interpreted by McLean (1994, p. 62), however, P. nevadensis is a highly vari- able species, with diameter of tabularium, number and length of septa, and in colonial form varying enough to encompass the Iowa specimens of P. minutissimum, which however, would have priority over the Stumm species from Nevada. Phillipsastrea exigua, from Frasnian strata of the Hay River region of western Canada, has been placed into synonomy with P. nev- adensis by McLean, who also figured its holotype (1994, p. 63, PIS, figs.3,4). P. exigua closely resem- bles many specimens of P. minutissimum, and is placed therein. DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 75 Pachyphyllum minutissimum resembles several spe- cies from Frasnian units of New Mexico. Pachyphyl- lum variabile, from the Sly Gap Formation is some- what smaller in mean diameter than is P. minutissi- mum, but primarily differs from the Iowa species by its tendency for septa to break up into trabecular pillars in the dissepimentarium. P. confluens, from the late Frasnian Contadero Formation, is approximately the same size and has approximately the same number of septa as does P. minutissimum, but is marked by great- er confluency of septa between corallites and reduced dilation of septa. This New Mexico species was rep- resented by a single specimen found in the uppermost Frasnian bed of the Contadero, thus is difficult to eval- uate. It may belong in the Iowa species. Occurrence.—P. minutissimum is the most common species of the genus in the uppermost unit of the Ma- son City Member. The holotype collected by Webster is labeled as originating from the Shellrock Formation at Nora Springs, Iowa; by its matrix composition and the common occurrence of the species, it presumably came from the uppermost meter of the Mason City Member in Nora Springs. The species has also been collected from the top of the Mason City at Koch’s reference section on the south side of Nora Springs (Locality 11, Appendix), from the upper 0.5 m of the Mason City at its type section (Locality 9) and from this horizon at the dam at the north edge of Nora Springs (Locality 8). It also occurs in the same posi- tion at the top of the Mason City at Cooper’s Bend (Locality 19), Roseboro (Locality 22), and from the most southerly outcrop examined, the Maxson Quarry at Marble Rock (Locality 23). The range of this spe- cies is consistent within the study area. Pachyphyllum gregarium Webster, 1905 Plate 1, figure 8; Plate 39, figures 1—5; Plate 40, figures 1—5 Pachyphyllum woodmani vat. gregarium Webster, 1905, p. 70. Diagnosis.—Variable species with tabularial diam- eter in the mid-range for North American species of the genus (3—4 mm) and number of septa ranging from 26 to 35. Septa usually short, leaving approximately / of the tabularium open at the axis. In some colonies, septa even shorter, with major septa only penetrating a short distance into tabularium. Septa dilated to vary- ing degrees, but usually occupy at least 50% of the area of the horseshoe dissepiments, and may be dilated sufficiently to form a solid ring around the tabularium. Septal confluency variable, but most commonly, septa are confluent with or abut against those of neighboring corallites. Tabularium occupied only by complete, flat or sloping tabulae. Description.—P. gregarium forms small, compact colonies. Four such colonies were available from the Rudd section, including the lectotype and paralecto- type collected by Webster, as well as two topotypes collected by me. The Rudd fauna has colonies that vary only from 3.4 to 3.6 mm in colony mean diameter of tabularium, and from 26.8 to 28.2 for mean number of septa. A larger sample of colonies from south of Rockford (Locality 21, Appendix) and Tom Williams Quarry (Locality 16) shows much more variability, from 3.2 to 4.3 mm in colony mean tabularium diameter, and from 27.8 to 37.2 in mean number of septa for 18 colonies (Text-fig. 42). There appears to be one cluster for Rudd colonies and another, larger cluster by size and septal number, of colonies from west and south of Rudd. In its most typical development, P. gregarium is composed of corallites mostly of the same approximate size, with septa either confluent with or abutting against septa of neighboring corallites. Where much budding has occurred, with a correspondingly large number of juveniles, many corallites are aphroid, and in several colonies, the aphroid form is pervasive in portions where budding has been abundant (P1.39, figs.1,4). Septa are clearly differentiated into major and mi- nor, and minor septa do not extend inside the sleeve of horseshoe dissepiments. Major septa generally ex- tend Y, to 7, of the way to the corallite axis, leaving a broad open area at the axis (P1.40, figs.1,3). In several colonies, major septa are even shorter, only extending Y; way into the tabularium (PI1.40, figs.2,4). Dilation is marked, but is often flat-sided, giving an elongate fu- siform appearance to septa in transverse section. Septal dilation is one of the highly variable features of the species, in some corallites sufficient to fuse septa into a solid ring over the horseshoes, in others only forming a porous ring in transverse section, with septa occu- pying Y, to Y, the area at the ring of horseshoe dissep- iments (as seen in transverse section). Also, in trans- verse section, stereome coating the outside of the horseshoe dissepiments is thick and can form a heavy envelope that coats both septa and horseshoes, rein- forcing their wall-like appearance. Several colonies have very heavy dilation of septa accompanied by ster- eome in the area of the horseshoes (P1.40, fig.3). These colonies tend also to have thick, heavy septa in the dissepimentarium and confluent septa with neighbor- ing corallites with thick septa, suggesting a parent-off- spring relationship. In longitudinal view, several important characters of the species are seen. The horseshoe dissepiments are uniformly sized and swollen, and their inner flank is 76 BULLETIN 355 often coated with stereome, as is the outer side of the sleeve. This coating is very thick in colonies with heavy skeletal development and heavy dilation of sep- ta. No accessory dissepiments are seen between the horseshoes and the tabularium (PI1.40, fig.5). The ta- bularium is occupied by rather flat tabulae, most of which are complete and horizontal or gently sloping. In some colonies tabulae sometimes sag, and in others, accessory incomplete tabulae are occasionally present, leaning against the outer border of the tabularium, sloping in towards the tabularial floor (P1.39, fig.5). The outer dissepimentarium most commonly con- tains large, irregular-shaped to flat and elongate dis- sepiments, and extends into that of neighboring cor- allites, without a well-defined boundary. This is es- pecially so in aphroid parts of a colony (PI1.40, fig.4). Septal trabeculae form tight fans centered over horseshoes. Trabeculae in this species are closely packed into the fans, although rhipidacanths do not show the common separation and wide spacing of hor- izontal rhipidacanth trabeculae (such as seen typically in P. crassicostatum). Type Specimens.—Lectotype USNM 78645B, des- ignated here, paralectotype USNM 78645A (labeled cotypes by Webster). Discussion.—This is the common species that oc- curs in biostromal carbonates of the Nora Member of the Shell Rock Formation. Pachyphyllum gregarium is characterized by rather large tabularial diameters and variation in the amount of confluency of septa between corallites. The lectotype specimens (USNM 78645A, 78645B) show considerable disruption of confluency, but the species as a whole shows great variability of this character. In its somewhat aphroid nature, the spe- cies resembles Phillipsastrea disrupta McLean, from western Canada. P. disrupta however, is larger and has more septa than P. gregarium, but is not far above the range seen in the Iowa species. P. gregarium shows a whole range from colonies with confluent septa (P1.40, figs.1—3) to colonies with partially or wholly aphroid nature (P1.39, figs.1,4, Pl.40, fig.4). Aphroid individ- uals are generally not greatly dilated, perhaps as a re- sult of a relationship between the colony form and active budding. P. gregarium may be related to P. dis- rupta, but the two are not conspecific. Occurrence.—P. gregarium is the common species of the Nora Member. Webster’s types were collected from outcrops and a quarry on Flood Creek at Rudd, Iowa (Webster, 1905, p. 70), and topotypic material was collected here by me from the upper biostrome of the Nora Member (Locality 12, Text-fig. 15). Collec- tion of a large number of colonies in an area bulldozed in 1967 during construction of the Shell Rock River bridge, 5.6 km (3.5 mi) south of Rockford, allows rec- eg ; 48} ---*---1------- 4------- 4------- j{----—-- faa----- oo « 46,------- f------ 4------- done ee = 4_------ _m.---- q------- Z ae ee pn a aie ae hic aoe aan cau wer ges San B 42}----| holotype }--_-<- ss eee oa ea 5 ; VARGO i =, it = 3 ia ee st iz i a Sea a a c \ ' 1 ' Hy Gllemeaas a =----=--- 4---=>* q------- a = > n=15 8 90) ae —— copes eas sears [o} i ' ' 1 ' 1 S) elle nee ea ApS ao Heamsas= Pees Weeeeaa, Gpllenaasod ——— 4----=-- +--, P. websteri | ----- tean-a-- 3 t t t : + : 45 5 55 6 6.5 7 75 8 Colony Mean Diameter of Tabularium - mm Text-figure 43.—Pachyphyllum websteri from the lower, bios- tromal beds of the Mason City Member, colony mean diameter of tabularium (in mm) plotted versus the colony mean number for the total septa in each corallite. The holotype of the species is identified on the graph. ognition of a range of variation within this species, as discussed above. Individuals assigned to this species have also been collected from the lower biostrome of the Nora at Rockford (Locality 20, Appendix), from the basal few centimeters of the Nora outcrop (presum- ably the upper biostrome) at the County Roads Quarry (Locality 14), at Tom Williams Quarry (Locality 16), and far to the north at the quarry north of Keidle’s Bluff, where it occurs in the basal centimeters of the upper biostrome of the Nora Member (Locality 1). Pachyphyllum websteri Belanski, 1928 Plate 41, figures 1—4; Plate 42, figures 1—5 Pachyphyllum websteri Belanski, 1928, p. 171, Pl. 12, fig. 3. Diagnosis.—Species of the genus with large diam- eter tabularium and weakly aphroid colony form; with fusiform, dilated major septa that extend a variable distance into the tabularium. Stereome on horseshoe dissepiments is commonly sufficient to form a solid ring around the tabularium. Tabularium filled with complete, flat or inclined tabulae, but with inner dis- sepiments lining the tabularium, within the sleeve of horseshoe dissepiments. Description.—P. websteri occurs as small colonies that are crowded with partially aphroid corallites. Col- ony mean tabularium diameter varies from 4.6 mm to 7.3 mm for 15 colonies studied, and the same colonies have mean septal numbers of from 35 to 45 (Text-fig. 43). The diameter of corallites is partly a function of maturity of the corallites (and their frequency of bud- ding), and this group of colonies has a diameter for DEVONIAN RUGOSE CORALS OF IOWA: SORAUF WT the largest corallite that ranges from 5.4 to 9 mm, with a mean 6.7 mm for the population. Septa are differentiated into major and minor septa on the basis of length and amount of dilation, with major septa commonly extending within the tabular- ium from ), to ¥, the distance to the corallite axis. Septal dilation is always well-developed, but because of the large diameter of the tabularium, septa still only occupy about /, of the space over the sleeve of horse- shoe dissepiments (PI.41, figs.2,4). Only in two colo- nies was sufficient stereome deposited over the horse- shoe dissepiments to form a complete, solid ring around the tabularium. Dilation of major septa is also somewhat peculiar in this species, as much of the di- lation of major septa occurs within the tabularium it- self, and the belt of maximum dilation can be centered over an obvious band of stereome that coats the inner flank of the horseshoe dissepiments. Minor septa sel- dom extend farther toward the corallite axis than the inner margin of the horseshoes. Horseshoe dissepiments are uniform and stacked in a straight sleeve surrounding the tabularium, but inner dissepiments occur within this sleeve, and are com- monly seen in transverse section as asymmetrical curved dissepiments attached at one end to a major septum. Commonly three or four rows can be seen in transverse sections. Horseshoe dissepiments them- selves are heavily coated with stereome both on their inner (tabularial) and outer sides. This coating can be as thick as the horseshoes are wide. In longitudinal section, the tabularium is filled with tabulae that are often complete and sagging or inclined so that the calicinal pit is flat on the bottom, but slop- ing at the margins of the tabularium (PI.41, figs.2,3). One to five rows of elongate, steeply inclined to ver- tical dissepiments are present axial to the horseshoe dissepiments (P1.42, fig.3). The external dissepimen- tarium is filled with large, flattened, somewhat irreg- ular dissepiments (PI1.41, figs.2,3). This outer dissepi- mentarium is rather narrow for the genus, and reflects the calicinal topography, with a depression between corallites expressed by rows of large and irregular dis- sepiments which are interspersed with rows of small, irregular ones. This size variation in dissepiments seems related to frequency of budding rather than pe- riodic (seasonal?) variation in corallite diameter (P1.42, fig.4). The septal monacanths of this species form tight fans centered on the horseshoe dissepiments (P1.42, fig.3). Type Specimens.—Holotype SUI 2176, paratypes SUI 529, USNM 71030. Discussion.—Aphroid colonies of P. websteri are variable in their development (P1.41, fig.2; PI.42, fig.4). In several, there is a suggestion of vertical band- ing of more aphroid and less aphroid portions of the colonies. In others, the axial portion of the colony is characterized by a higher percentage of recently bud- ded corallites, and an accompanying more aphroid re- lationship between corallites. The apparent relation- ship between budding rate and the degree to which the aphroid colonial form is developed is striking; in nu- merous colonies budding is much more abundant in the axial portion of the colony, and indeed, corallites are more aphroid here. Where banding is suggested, this can be as easily related to seasonal variation in the rate of budding as to variation in rate of skeleto- genesis. In one colony of P. websteri, twinned, axial budding occurred, originating directly from the tabu- larium of the parent (P1.42, fig.5). This is the only example known to me of parricidal budding in the ge- nus. In its partially aphroid colonial form P. websteri is reminiscent of Phillipsastrea disrupta from western Canada (McLean, 1994, p. 67), but the Iowa species has larger tabularial diameters (up to 9 mm) and many more septa than P. disrupta. Another similar species is that described as Pachyphyllum ibergense var. pro- gressa by Rozkowska (1953, p. 48, pl.5, fig.8). The Polish form is approximately the same size as P. web- steri, but has many fewer septa and is more aphroid than the latter. Occurrence.—The Belanski types are from lower Mason City biostromal beds in a former quarry in southern Nora Springs (Locality 11, Appendix). Ac- cording to Belanski (1928, p. 174), P. websteri typi- cally occurs in the lower biostromal beds of the Mason City, which he called the ““Aulopora zone’’. Individ- uals of P. websteri have been collected in numbers from the lower Mason City biostrome at its type sec- tion (Locality 9, Appendix), south of Nora Springs (Locality 11), at Kapka’s Farm (Locality 18), and at Cooper’s Bend (Locality 19). In addition, three colo- nies with larger corallites have been collected from the lower biostrome of the Nora north of Nora Springs (Locality 2), at Reed Creek (Locality 4), and at Rudd (Locality 12). These few colonies fit well into P. web- steri, having major septa dilated well into the tabular- ium, and with steeply inclined dissepiments occurring in the innermost dissepimentarium, inside the horse- shoe dissepiments. In one of these colonies, skeleton is thicker than normal and septa tend to be confluent; more so than in some colonies of P. websteri. The Nora Member is generally characterized by P. gregar- ium, but the three specimens fit well into P. websteri, and I regard them as an upward extension of its local range (P1.42, fig.6). 78 BULLETIN 355 Pachyphyllum woodmani (White, 1870) Plate 2, figures 8-11; Plate 3, figures 1—4; Plate 43, figures 1—6; Plate 44, figures 1-5; Plate 45, figures 1-5; Plate 46, figures 1—6; Plate 47, figures 1—5 Smithia woodmani White, 1870, p. 188. Pachyphyllum woodmani Hall and Whitfield, 1873, p. 231; Webster, 1889a, p. 622; Fenton and Fenton, 1924, p. 46, Pl. 7, figs. 1-3, Pl. 8, fig. 2, Pl. 9, figs. 11-12, Pl. 10, figs. 3; Ehlers, 1949, p. 2, Pl. 3, figs. 1-4; Stumm, 1949, p. 74, Pl. 17, fig. 24; Sorauf, 1978, p. 820, Pl. 1, figs. 1-4, Pl. 2, figs. 1-4, Pl. 3, figs. 1-5, Pl. 4, fig. 1. Pachyphyllum ordinatum Webster, 1889a, p. 624. Pachyphyllum levatum Webster and Fenton, in Fenton and Fenton, 1924, p. 48, Pl. 5, fig. 4, Pl. 12, figs. 9-10. Pachyphyllum irregulare Webster and Fenton, in Fenton and Fenton, 1924, p. 49, Pl. 10, figs. 1,2, Pl. 11, figs. 1,2. Pachyphyllum crassicostatum nanum Fenton and Fenton, 1924, p. 52) PISO: figs (6: Phillipsastrea woodmani Stumm, 1940, p. 64: McLean, 1994a, p. 58, Pl. 1, figs. 3-6, Pl. 2, figs. 1—6, Pl. 3, figs. 1—4. Pachyphyllum vagabundum Ehlers, 1949, p. 1, Pl. 2, figs. 1-3. Medusaephyllum woodmani Sorauf, 1988, p.175, figs. 20.3—20.6, 22.1—22.4, McLean and Sorauf, 1989, p. 393, Pl.1, figs. 3,4. ?Phillipsastrea irregularis McLean 1994a, p. 64, Pl. 6, figs. 6-8, Pl. 7, figs. 1-7, Pl. 8, figs. 1-3,5. Diagnosis.—P. woodmani consists of small to me- dium-sized coralla with markedly excert corallites. Septa dilated at boundary between tabularium and dis- sepimentarium, forming sleeve around tabularium. Uniform sleeve of horseshoe dissepiments most com- monly, but not invariably, formed under area of septal dilation. Septa most often confluent between corallites, but colonies sometimes partially aphroid. Major septa long and either reach to axis and unite to form aulos- like structure, or reach near axis and swirl around small open space. Minor septa generally extend only short distance past the horseshoe sleeve into tabular- ium. Dissepimentarium characterized by interior, steeply inclined dissepiments inside heavily stereome- coated horseshoe dissepiments. Outer dissepiments normal with varying sizes, merging with outer parts of neighboring corallites. Description.—P. woodmani generally occurs in flat- tened colonies with sharply exsert corallites. Corallites are of medium diameter for the genus, and colonial form generally is thamnasterioid, more rarely partially aphroid (P1.43, figs.1—3). The species is characterized by well-developed, uniform horseshoe dissepiments. This, together with pronounced septal dilation, forms a solid sleeve around the tabularium, made of diver- gent rhipidacanth trabeculae plus abundant stereome coating the horseshoes. The outer dissepimentarium is formed of numerous globose dissepiments, with layers of larger, irregular dissepiments occurring at regular intervals. Major septa are long and commonly deflect- ed in the axial area to form a structure approaching, but not attaining the solid ring of an aulos (PI.43, figs.4,5,6). Minor septa most commonly do not extend beyond the thickened collar zone of the inner disse- pimentarium. There are one to four rows of steeply inclined dissepiments, inside the ring of horseshoe dis- sepiments. The tabularium has flat to slightly sagging tabulae peripherally, and axial disruption of tabulae by long septa, so that in some corallites there is the de- velopment of an axial row of tabulae. Type Specimens.—Neotype NYSM 3580/1, desig- nated by Sorauf (1978, p. 821). Topotypes of P. wood- mani, FMNH 26016, 26017, were noted as ‘‘plesio- types” by Fenton and Fenton (1924, p. 47). Species synonymized with P. woodmani are; Pachyphyllum or- dinatum, holotype, USNM 78646, P. levatum, holo- type USNM 78629, P. irregulare, holotype USNM 78615, and the subspecies, P. crassicostatum nanum, holotype FMNH 26018. Discussion.—The highly variable species Pachy- phyllum woodmani is very abundant in the Cerro Gor- do Member, especially in the upper part. At the time of the Webster and Fenton study, variability within this population was not well understood; thus species and subspecies names for variants of the species were pro- posed, generally on the basis of one or two colonies, at times without sectioning specimens. The Hall and Whitfield neotype (NYSM 3580/1) is a good one, with characteristics that are very typical of the species (P1.43, fig.4). This specimen has been thin sectioned and photos of sections published pre- viously by Sorauf (1978, p. 821). The figured topo- type of Fenton and Fenton, USNM 26017, also strongly resembles the neotype, although not having as much stereome thickening on horseshoe dissepi- ments. Septal dilation is not extreme in the neotype or in most topotypes, where about /, of the perimeter of the tabularium is occupied by inflated septa. Di- lation of septa has a “‘straight-sided’’ appearance, and is accompanied by the deposition of stereome on horseshoe dissepiments to form a marked “halo” around the tabularium. Of the two FMNH topotype specimens, one (26016) has septal dilation similar to that of the neotype, but heavier stereome coating; the other has similar dilation, but heavy stereome only present on the inner side of the horseshoes. Colony form varies somewhat, mostly in the amount of con- fluency of septa from one corallite to another. In most specimens, confluency is best developed where bud- ding is not frequent, and is absent where budding oc- curs in the outer dissepimentarium. Thin sections of the holotype of Pachyphyllum or- dinatum Webster (1889a, p. 624) indicate that it be- longs to a group common within P. woodmani char- acterized by diameters at the small end of variation DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 79 and very heavy dilation of septa accompanied by heavy deposits of stereome on horseshoe dissepi- ments (USNM 78646, P1.45, fig.1). The occurrence of such colonies with very heavy collar of stereome surrounding the tabularium was recognized by Fenton and Fenton, who changed the status of the taxon to a subspecies, P. woodmani ordinatum (1924, p. 47). Because this occurs commonly within the P. wood- mani population, I would not differentiate it from oth- ers. The morphotype is a distinct one, because of the solid collar surrounding the tabularium, with long major septa that are irregularly bent at the corallite axis, but do not swirl to form the small “‘pseudo- aulos”’ that is common within the species. Trabecular fans are also very tight, and trabeculae and stereome together can hide horseshoe dissepiments in longitu- dinal section. Fifteen corallites in the holotype have a mean tabularium diameter of 2.8 mm, with a colony mean number of septa of 28.1 (Text-fig.44). Thus, P. ordinatum comprises a group of P. woodmani with small-diameters, and the small corallites have few septa. Size is not uniform throughout all heavily di- lated colonies within the species. Fenton and Fenton were correct when they wrote that, “there is in no respect a clear demarcation from the less exsert forms of woodmani” (1924, p. 48). As can be seen in Plate 46, figures 1—6, there is a complete spectrum from colonies with a relatively light weight skeleton to those with heavy calcification and abundant stereome, encompassing various “‘subspecies”’ of P. woodmani. The holotype of the species P. Jevatum was not sec- tioned by Webster and Fenton. They illustrated photos of the external surface of these corals with prominent calicinal necks on the upper surface (Fenton and Fen- ton, 1924, pl. 12, fig. 9) and undersurfaces showing holotheca absent (eroded?), revealing prominent rounded corallites at the margins of colonies (Fenton and Fenton, 1924, pl. 12, fig. 10, and pl. 5, fig. 4). The latter is a photograph of the undersurface of a colony that obviously was turned over and lay exposed on the sea floor long enough for a sizeable colony of auloporid corals to grow on it. Thin sections of the holotype show medium-sized corallites (mean tabular- ium diameter of 3.04 mm with mean number of septa of 31.6 for 16 corallites, Text-fig. 44). As can be seen in figures 2 and 3 of Plate 44, the holotype of P. lev- atum is clearly a specimen of P. woodmani with heavy septal dilation, moreso than in the neotype, but lacking the solid ring shown in transverse sections of the ho- lotype of P. ordinatum. Septal dilation here is flat- sided and forms an almost solid collar around the ta- bularium. The tabularium is filled with flat, interrupted tabulae and is strongly reminiscent of the ordinatum holotype and also the figured specimens of Fenton and Colony Mean Number of Septa £ ' \ ' ' ' \ ' ' ' ' i i] t 45 50 55 60 Wet Sta t —-——+ 25 30 35 40 Colony Mean Diameter of Tabularium - mm Text-figure 44.—Pachyphyllum woodmani from throughout the upper units of the Cerro Gordo Member, colony mean diameter of tabularium (in mm) plotted versus the colony mean number for the total number of septa in corallites. The holotypes of synonymized species are also indicated on the graph, namely for Pachyphyllum levatum, Pachyphyllum ordinatum, and Pachyphyllum irregulare, all species of Webster or Webster and Fenton. Fenton (FMNH 26016, 26017). Septa are confluent to a greater degree than in many colonies, but there also is an absence of budding in this section and the degree of confluency may thus reflect the growth stage within the colony. Likewise the holotype and paratype of P. irregulare Webster and Fenton, in Fenton and Fenton, 1924, p. 49 were figured in external view only (1924, pl.10, figs.1,2). These are decorticated specimens with growth that is irregular in direction, and colonies fea- ture very strongly exsert calicinal prominences sur- rounding tabularia. The holotype has ovoid corallites, and measuring the long diameter provides an exag- gerated idea of their size. The longitudinal section is that of a very typical P. woodmani, except that it 1s a large P. woodmani. Five corallites in the holotype have a mean long diameter of 4.2 mm and a mean number of septa of 41.8 (Text-fig. 44), while a sixth corallite is incomplete, but apparently had a long diameter of 5.2 mm, large for a P. woodmani (P1.47, figs.1,3). The paratype has even larger corallites; three corallites here have means of 5.7 mm for the long diameter and 39 for septa. In all other characters the types resemble P. woodmani. McLean (1994a, p.64) accepted this as a valid species, and included large numbers of P. wood- mani-like corals from western Canada in his Phillip- sastrea irregularis. lowa specimens, however, fit with- in the size range of P. woodmani, and can not be dif- ferentiated from them. The last of the taxa resulting from the Fenton and Fenton study is Pachyphyllum crassicostatum nanum 80 BULLETIN 355 (1924, p. 52), which they reported as coming from the upper Cerro Gordo Member. No individuals have been seen in upper Cerro Gordo beds that warrent place- ment in this subspecies, and the one specimen figured by them in 1924, the holotype (pl.9, fig.6, FMNH 26018), strongly resembles P. woodmani in thin sec- tion, but with larger corallites than usual for the latter. Its only peculiarity is that it appears to have more strongly differentiated septal rhipidacanths than com- mon in P. woodmani. Fenton and Fenton noted that the subspecies was uncommon, but was found at Hackberry Grove and at Rockford. No specimens were collected that resemble theirs. Some small colonies show a long founder corallite that grew to adult diameter prior to budding (PI.2, figs.8-10). As most of these founder corallites devel- oped from larval settlement on a hard substrate, they sometimes have an impression of a brachiopod or oth- er organic debris on their base (PI.2, fig.10). Occurrence.—Fenton and Fenton noted that P. woodmani 1s characteristic of the upper part of the De- vonian of Iowa. They noted that it appears in the lower “Spirifer zone” and is present throughout the Cerro Gordo Member. They stated that, “‘In the Owen it is more or less replaced by varietal forms” (1924, p. 47). I did not find corals assignable to this species above the Cerro Gordo Member. Abundant specimens of P. woodmani were collected at all sizeable outcrops of the upper part of the member, the ““Spirifer zone”. The neotype for the species comes from the former Rock- ford Brick and Tile Co. quarry (Locality 35, Appen- dix), where specimens were collected from all units of the argillaceous limestones and calcareous shales of the upper Cerro Gordo, which were stripped from un- derlying beds in order to quarry the shales of the Ju- niper Hill Member. Abundant P. woodmani were also collected from throughout the South Portland sections (Localities 27 and 27A) and especially from the “‘rusty bed”, at the type Lime Creek section (Locality 28), where the species is also abundant throughout the up- per part of the sequence. Bird Hill and Bird Hill South (Localities 31 and 32) furnished many specimens also, as did County Road North (Locality 29). In all of these localities, the species was at one time extremely abun- dant. It is still abundant locally, but many localities have been heavily collected and specimens are less common. Colonies of P. woodmani are most easily found in numbers today by searching in plowed fields (Locality 28b) neighboring the type Lime Creek sec- tion. The species also occurs in western Canada, New Mexico, Nevada and New York. Pachyphyllum crassicostatum Webster, 1889 Plate 3, figures 5,6; Plate 48, figures 1—5; Plate 49, figures 1—6; Plate 50, figure 1 Pachyphyllum crassicostatum Webster, 1889, p. 623; Fenton and Fenton, 1924, p. 51, Pl. 8, fig. 1, Pl. 9, figs. 1-5; Sorauf, 1978, p- 827, Pl. 4, figs. 2-5. Pachyphyllum owenense Webster and Fenton, in Fenton and Fenton, 1924, p. 50, Pl. 7, fig. 5. Pachyphyllum ct. P. crassicostatum McLean, 1986, p. 448, figs. 48 .32—48.33. Pachyphyllum anfractum McLean, 1986, p. 447, figs. 48.28—48.31. Diagnosis.—Large-diameter species of the genus with long major septa either joined at corallite axis or with irregular inner portion surrounding small open axial space. Septal trabeculae strong rhipidacanths with marked separation between laterally diverging trabeculae. Septa generally greatly dilated over sleeve of uniform horseshoe dissepiments; many (but not all) colonies with septa dilated into lateral contact with one another. Interior dissepiments present within sleeve of horseshoe dissepiments. Septa generally confluent be- tween corallites. Tabularium with periaxial rows of saucer-shaped tabulae and characteristic wavy axial ends of septa seen interrupting tabulae in longitudinal section. Species sometimes occurs as colonies in which founder corallite has considerable length and has grown to mature diameter prior to budding. Description.—P. crassicostatum generally occurs as compact thamnasteroid colonies with excert corallites extending 6 to 9 mm above the general surface of the colony. This surface bears septal ridges that are largely confluent between corallites. At their greatest, these colonies have a diameter of approximately 18—20 cm. Some small colonies are characterized by having a long founder corallite with budding occurring only above the stalk-like, mature founder (PI.3, fig.5). P. crassicostatum colonies have large corallites, with colony means for tabularium diameter ranging from 3.9 to 10 mm for 34 colonies, with the colony mean number of septa varying from 34 to 59 (Text- fig. 45). These means vary somewhat with geography, as discussed below. In addition, these measurements are affected by the number of immature corallites within the colony. If only the largest corallite in each colony were considered, these would range from 4.0 to 11.2 mm, and have a mean of 7.5 mm in these 34 colonies. Septa are clearly differentiated into major and minor series, with major septa commonly extending close to the axis of the corallite where they may join to form an axial boss or they may have an irregular form and terminate around a small open space (PI1.48, figs.1,4). This terminal irregularity is seen both in transverse (P1.49, fig.2), and in longitudinal sections (PI1.49, DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 81 Colony Mean Number of Septa P. crassicostatum |~ Colony Mean Diameter of Tabulanum - mm Text-figure 45.—Pachyphyllum crassicostata of the upper Owen Member, colony mean diameter of tabularium (in mm) plotted versus the colony mean for total number of septa in corallites. In addition to the holotype of this species shown on the graph, that of Pachy- phyllum owenense Webster and Fenton is also shown, as it is con- sidered to be a small diameter colony of P. crassicostatum. fig.5), and is characteristic for the species wherever the septa are long. Minor septa are somewhat unusual for the genus in that they may extend some distance past the horseshoe dissepiments rather than terminating at their inner margin. At the extreme, minor septa may extend as much as Y, as far into the tabularium as do major septa. Septa all dilate at the position of the horseshoe dissepiments in the inner dissepimentarium and lateral divergence of rhipidacanth septal trabeculae is obvious in transverse sections. Extreme dilation (three to four times “‘normal”’ thickness) is seen in some colonies, with septa almost joining laterally over the horseshoes. At the other extreme, some colonies show relatively little dilation, so that less than /, the perimeter of the tabularium is occupied by septal ster- eome, and septa have a fusiform dilation, as so often seen in the genus and family. Septa are generally con- fluent between corallites (P1.49, figs.1,2); budding, however, tends to disrupt confluency. In longitudinal section, the structure within the ta- bularium often appears irregular due to interference between long major septa and tabulae (P1.48, fig.5). Within colonies characterized by corallites with short septa, the central part of the tabularium is occupied by flat but irregular tabulae. Where septa are long and joined or nearly joined at the axis, periaxial rows of uniformly sagging tabulae commonly occur at the mar- gins of the tabularium (PI1.49, fig.5). The irregular na- ture of the axial margins of septa can be seen in both transverse and longitudinal sections. There was a con- tinued, irregular twisting of the axial portion of the polypal base during growth and skeletogenesis. In longitudinal section are also seen the extreme rhipidacanth septal trabeculae. These are all widely spaced and isolated from one another by septal ster- eome over the horseshoe dissepiments (P1.49, figs.3,4). Trabeculae can be seen bending away from a diver- gence line in the plane of the septum; where septa are dilated, trabeculae can be seen bending to the horizon- tal, thus perpendicular to the septal plane. In some specimens this has the appearance of small, carinae- like lateral extensions, covered smoothly by stereome (as seen in transverse sections); rhipidacanths do not extend beyond the lateral margins of the septa. The dissepimentarium is marked by a very promi- nent and uniform row of horseshoe dissepiments that are secondarily thickened by stereome, commonly with a heavy coating of stereome on both the interior and exterior side of the horseshoes (P1.49, fig.3). On their interior side there generally occur only one or two rows of steeply inclined normal dissepiments (P1.48, fig.5). External to the horseshoes are seen elon- gate and flattened or small and somewhat globular dis- sepiments. Generally these layers of normal dissepi- ments arch upward to the horseshoes, reflecting the exert nature of the calice, and this arrangement is re- flected in the septal trabeculae which are vertically ori- ented between corallites and grade into fans over the sleeve of horseshoes at the margin of each corallite tabularium. Type specimens.—Lectotype USNM 78628A, par- alectotype USNM 78628 (here designated). P. owe- nense holotype is FMNH 25982 (erroneously listed as FMNH 26054 by Fenton and Fenton, 1924, p. 51), paratype is USNM 78627. Discussion.—P. crassicostatum is a large diameter, strongly exsert species of the genus. As such it is strongly reminiscent of the type species of Pachy- phyllum Milne-Edwards and Haime (1851), who noted that this species, P. bouchardi, from the Boulonnais region of northern France, has corallites with diame- ters of 15 to 20 mm, which is about twice the diameter of the Iowa forms, and with exsert tabularia apparently extending 6 to 8 mm above the surface. P. mirusensis McLean (1986, p. 449) is apparently also a species of Pachyphyllum with larger sized tabularium than that of P. crassicostatum. Webster (1889, p. 623) did not illustrate or designate any types for the species. Later, Fenton and Fenton (1924, p. 52) noted that “‘cotypes”” were in the “‘Col- lection of C.L.Webster”. The specimens are now USNM 78628 and 78628A, each labeled ‘‘cotype”’. I here select USNM 78628A as lectotype; the second specimen, USNM 78628 is lectoparatype. The two specimens labeled “‘plesiotypes”’ by Fenton and Fen- ton (1924, p. 52) are regarded as topotypes. Locality 82 BULLETIN 355 information on the type specimens is sketchy: ““Owen Grove, Iowa’’. This is presumably Locality 25 (Ap- pendix), on the west side of Owen Grove, along Owen Creek, which yielded numerous fine coral specimens to both Webster and Charles Belanski from the upper- most beds of the Owen. Within the Iowa fauna, there are apparently two more or less distinct morphotypes, one with smaller diameter and somewhat fewer septa than the other. The sizeable collection of specimens from the Lillibridge Quarry (Locality 38) generally have larger corallites and contain many more septa than the population cen- tered on specimens from the Morgan Quarry to the southeast. This may be environmental as well as bio- geographic, as specimens collected from Owen bio- stromes in the Morgan Quarry are close to those from biostromes in the Lillibridge quarry. Colonies from Owen Grove can have large corallites with many septa, or be somewhat smaller, as is the lectotype of the spe- cies. Pachyphyllum owenense Webster and Fenton, in Fenton and Fenton 1924, occurs within the population with small corallites, as noted above in P. crassicos- tatum, and is indeed smaller and has fewer septa than do the typical large corallites of colonies of the latter (P1.45, fig.3). I consider the Webster and Fenton spe- cies to be synonymous with P. crassicostatum (Text- fig. 45). P. crassicostatum has also been found in Frasnian rocks of New York State (Sorauf, 1978, p. 827), and the fauna there is remarkably similar to that of Iowa, although major septa tend to be slightly shorter and the colonies from New York appear to be more aphroid than do the Iowa ones. The species also occurs in Fras- nian strata of western Canada. McLean (1986, p. 448) referred specimens to Pachyphyllum sp. cf. P. crassi- costatum. My opinion, based on his published figures, is that these fit well into the Iowa species, although they are more aphroid than some. McLean’s species P. anfractum (1986, p. 447) also fits within the range of variation in septal dilation and tabularium diameter present in the Iowa fauna of P. crassicostatum and is here synonymized. Additionally, it is also possibile that P. miniaceum McLean (1986, p. 446) should also be placed within the Iowa species, but it is very regular in size, shape, and degree of septal dilation in coral- lites, moreso than those of the P. crassicostatum fauna in Iowa. Occurrence.—P. crassicostatum is the typical upper Owen species throughout the northern area of outcrop. It is the thamnasterioid coral of the ‘“‘Acervularia zone”’ of Fenton and Fenton (1924, p. 8), the term they used for the uppermost limestones of the member. P. crassicostatum does not occur in the upper Owen in 8 Colony Mean Number of Septa 8 = { u i ‘ i : i ee 1.4 1.6 18 2 2.2 2.4 2.6 28 3 Colony Mean Diameter, Tabularium in mm Text-figure 46.—Phillipsastrea dumonti n. sp. from the upper Owen Member, colony mean diameter of tabularium (in mm) plotted versus the colony mean for total number of septa in corallites. The holotype of this new species is indicated. the most southerly area, where this uppermost unit is quarried, south of Dumont, Iowa. Here the species was apparently replaced by P. dumonti, characterized by very small corallite size. P. dumonti and P. crassicos- tatum occur together only in the Morgan Quarry (Lo- cality 39, Appendix), which is situated between Lilli- bridge Farm Quarry (Locality 38), where P. crassi- costatum was abundant, and more southerly quarries, where it was totally absent. P. crassicostatum was abundant in uppermost Owen beds at Owen Grove Quarry (Locality 26, Appendix), in the pasture along Owen Creek to the west (Locality 25), in these same beds at Rockwell (Locality 36), and formerly at Linn Grove Park in Rockwell (Locality 37), as well as oc- curring in great numbers at Lillibridge Quarry (Local- ity 38), as noted above. Pachyphyllum dumonti, new species Plate 50, figures 2—5; Plate 51, figures 1—5 Diagnosis.—Small-diameter species of the genus with colony mean diameter of tabularium ranging from 1.6 to 2 mm. Long major septa generally 10 to 12 in number, extending to corallite axis and forming either weak columella or an aulos. Colonies are thamnaster- ioid to aphroid, with heavy dilation of septa over horseshoe dissepiments. Description.—Colonies are large and massive, thamnasterioid to aphroid, and up to 40 cm in diameter and 10 cm in thickness. In transverse section, the small corallite tabularium is characteristic, with colony mean diameter varying from 1.6 to 2 mm in seven colonies studied, while the mean number of septa per corallite varies from 21 to 24 in these same colonies (Text-fig. 46). The species DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 83 is more constant in diameter of tabularium and number of septa than are most other species of the genus. Septal dilation at the outer margin of the dissepi- mentarium is marked and heavy, forming a massive sleeve in which dilated septa are in lateral contact (P1.50, figs.2—4). This characteristic is somewhat vari- able, and some colonies show less septal dilation, still spindle-shaped, with septa which are distinctly sepa- rate (PI.51, fig.1). In colonies where dilation is heavy, some areas have corallites with less dilation, and these are places where budding has been rapid and recent (PL.51, fig.2). Minor septa are short and do not enter the tabular- ium, while major septa are long. The long major septa in this species commonly form a small diameter aulos at the corallite axis (P1.50, figs.3,4). This may be either a solid aulos or a somewhat irregularly formed colu- mella. Septa are generally confluent between corallites, but all colonies are at least partly aphroid. Even in colonies with overall confluency, no corallites totally lack aphroid septa. Dilated portions of septa are spin- dle-shaped (PI.51, fig.5). In longitudinal section, septal rhipidacanths form very tight fans over the horseshoe dissepiments at the outer margin of the tabularium. The horseshoe dissep- iments themselves form a uniform sleeve, and at times are only seen with difficulty in thin-section due to their being masked by the extreme dilation of septa; thus, they are best seen where septa are more spindle-shaped (P1.51, figs.3,4). The tabularium is dominated by the presence of the aulos, separating a row of flattish to slightly sagging axial tabulae from a periaxial series of uniformly sagging tabulae (P1.51, fig.4). Dissepi- ments are generally small and numerous, with 12 to 15 rows between neighboring tabularia. Dissepiments are occasionally large and flattened, and tend to occur along horizons which parallel growth surfaces. Type Specimens.—Holotype PRI 44820; paratypes PRI 44821, 44822, 44823. Discussion.—Small-diameter species of Pachyphyl- lum (and/or Phillipsastrea) are common in North America. They all have characteristics in common with P. dumonti. Phillipsastrea nevadense Stumm, 1940 is one such species from the Nevada Limestone in what was the White Pine Mining District in central Nevada. In Stumm’s illustration (1940, p. 64, pl.8), the specimen shown has a small-diameter tabularium and long major septa apparently forming an aulos, although this was not mentioned in Stumm’s description. The septal di- lation in P. nevadense does not compare to that de- veloped in Pachyphyllum dumonti; septa do join lat- erally, but barely so, as dilation is much more restrict- ed and limited in area. The tabularium diameter ap- proximating 3 mm is larger than that of P. dumoniti, and its degree of septal confluency is also much great- er. Phillipsastrea exigua Lambe, 1901, as described by Smith (1945, p.42), from the MacKenzie River region of western Canada, is another small diameter species. It is smaller than P. dumonti, with the diameter of its tabularium approximately | mm and with fewer septa (16-20). In P. exigua, major septa are shorter than in the Iowa species, only just reaching into the tabular- ium, and the colonies are very strongly aphroid, with septa restricted to the immediate area around the ta- bularium. This is, however, a variable character, and some colonies in the Iowa fauna have tabularia com- pletely free of septa, with septa more extensively de- veloped in the dissepimentarium. Pachyphyllum variabile (Sorauf, 1988) from the Sly Gap Formation of southern New Mexico is similar in several features to the Iowa species. In its size, length of major septa and the aulos sometimes present it re- sembles P. dumonti. The New Mexico species does not have the degree of septal dilation that P. dumonti does, and additionally, it is characterized by the break- down of septa in the dissepimentarium into trabecular pillars marking septal paths. Each of these species occurs in Frasnian rocks in the company of other species of the genus, one of which commonly resembles P. woodmani. In Frasnian strata of New York, two subspecies of P. woodmani have been recognized on the basis of corallite sizes. The smaller subspecies, P. woodmani avocaensis, has a complete range of size from those typical of the spe- cies to those typical of this eastern subspecies, with diameters in the 2 to 2.5 mm range. The smallest in- dividuals of the New York subspecies resembles P. dumonti, with long septa forming an aulos and with similar septal dilation. It characteristically has more confluent septa than the Iowa species. P. dumonti has uniformly smaller-diameter corallites, and occurs in much younger rocks in Iowa. Several colonies of P. dumonti have marked band- ing, appearing in transverse sections as rows of ster- eome coated and thickened septa connecting neigh- boring corallite tabularia (P1.51, figs.1,2). This is a re- flection of growth variation, and these dark bands ap- parently mark positions of slow growth at colony margins, as it is most obvious in the peripheral parts of the colonies. In one colony it is clear that such a growth line separates an area of more weakly dilated, aphroid corallites from a second area of corallites with more typically dilated, more confluent septa. Possibly two colonies have grown together along this boundary to form one large mass. Occurrence.—P. dumonti is common in the upper- 84 BULLETIN 355 most portion of the Owen Member, but only in the southern area of the Owen (in quarries). The holotype is from the uppermost 1.5 m (5.5 ft.) of the Owen at the Carrollus Quarry (Locality 41, Appendix). Other colonies have been collected from this same horizon in the Buseman Quarry south of Dumont, Iowa (Lo- cality 40) and one specimen was found in the upper- most 0.6 m (2 ft.) of the Owen at the Morgan Quarry, near Airdale, Iowa (Locality 39). The species is thus restricted to the area in Townships 91 and 92 North, in Franklin and Butler Counties. Etymology.—Named for the town of Dumont, Iowa. Genus TRAPEZOPHYLLUM Etheridge, 1899 Trapezophyllum Etheridge, 1899, p. 32: Hill, 1939, p. 234; Glinski, 1955, p. 107; Schouppé, 1958, p. 228; Pickett, 1967, p. 31; Sorauf, 1972, p. 433; Hill 1981, p. F284; McLean, 1989, p.242. Sulcorphyllum Pedder, 1963, p. 366. Type Species.—Cyathophyllum elegantulum Dun, 1898. Diagnosis.—Cerioid phillipsastreid genus character- ized by rhipidacanth septal trabeculae in well-devel- oped, symmetrical fans and uniform sleeve of horse- shoe dissepiments, generally with stereome rather heavily deposited on both septa and horseshoes. Row of flat, ladder-like dissepiments often present in cor- allite periphery. Colonial form diagnostic for the ge- nus, with truly cerioid walls (epithecal) separating cor- allites. Discussion.—Published data on Trapezophyllum fo- cuses on Australian and German Middle Devonian species. As proposed by Etheridge, and illustrated by Hill (1939), Glinski (1955), Schouppé (1958), Pickett (1967), Sorauf (1972) and others, the genus has been regarded as a phillipsastreid in the narrow sense, with rhipidacanth septal trabeculae in fans centered over a sleeve of horseshoe dissepiments, and with distinctive flat dissepiments seen in longitudinal section as a sin- gle row peripheral to the horseshoes. The genus has a truly cerioid colonial form, with an epithecal wall sep- arating corallites. Seen in longitudinal section, the lad- der-like row of dissepiments separates the horseshoe dissepiments from the epithecal wall. This distinctive genus, with dissepimental “‘ladders” is known from Lower and Middle Devonian rocks of Australia, Ger- many and China (Hill, 1981, p. F284), and from Wash- ington State in North America (Sorauf, 1972). The stratigraphic position of the Washington material is questioned by new data on the age of Devonian rocks at Limestone Hill in northeastern Washington, once regarded as composed solely of Middle Devonian car- bonates, but now known to contain Frasnian strata as well (McLean and Pedder, 1987, p. 158). There is also an undescribed species of Trapezophyllum in the Fras- nian Martin Limestone of Arizona (McLean and So- rauf, 1989, p. 390). In Hill’s 1981 revision of the Rugosa, she figured topotypic material of the type species of Trapezophyl- lum, T. elegantulum (Dun), and showed clearly that this species is characterized not just by ladder-like dis- sepiments, but also that, “‘In some the flat dissepiments are replaced by a few series of abaxially declined or subhorizontally based globose dissepiments” (Hill, 1981, p. F284). Thus, the genus concept is broadened considerably, as cerioid phillipsastreids with flat outer dissepiments or with some globose dissepiments, can both be placed in the taxon. In Hill’s photographs of topotypes of Trapezophyllum elegantulum (1981, fig.183, 2a-c), longitudinal sections are shown with nu- merous normal dissepiments external to the horseshoe dissepiments, with the outer, ladder-like dissepiments only occupying the peripheral position. This broad- ened definition of the genus embraces the specimen described here from the Shell Rock Formation of Iowa. It also makes the genus Sulcorphyllum Pedder a junior synonym of Trapezophyllum. In Pedder’s de- scription of his genus he stated, “‘In its possession of outer flat dissepiments Sul/cophyllum resembles Tra- pezophyllum which is also cerioid, but there is no zone of outwardly convex dissepiments between the horse- shoe and flat dissepiments in Trapezophyllum” (1963, p. 366). Since normal, convex dissepiments are now known to be abundant in the type species of Trape- zophyllum, there is no reason to retain the additional genus name. The existence of normal dissepiments in the topotypes figured by Hill and the relationship with Sulcorphyllum also have been discussed thoroughly by McLean (1989, p. 242). The genus Smithicyathus was proposed by Roz- kowska (1980, p. 18), based on the type species S. cinctum Smith 1945, from western Canada. S. cinctum is characterized especially by aphroid septa, with cer- ioid walls enclosing more than one corallite and with walls lacking between the enclosed aphroid individu- als. It is of very late Frasnian age. The Shellrock spec- imen shows neither the tendency toward aphroid cor- allites, nor does it enclose multiple corallites within its cerioid walls. It does, however, develop a subphacel- loid form that was also cited as typical for Smithicy- athus (Rozkowska, 1980, p. 18), but perhaps has an ecological origin, as a response to sediment accumu- lating adjacent to the coral polyps. Trapezophyllum species A Plate 52, figures 1—3 Description.—This colony is cerioid. Not only does it have an epithecal (three-layered) wall, but these walls separate all corallites in the colony. A few cor- DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 85 allites grow free from the upper surface of the massive colony, and these also have an epithecal wall, which is commonly abraded away, perhaps due to its thin- ness. In transverse sections, corallites range in size from 4.0 to 5.8 mm for the diameter of tabularium and con- tain 38 to 46 septa in two series. Mature-appearing corallites in this colony have tabularium diameters that range from 4.9 to 5.8 mm, and have 42 to 46 septa equally divided into major and minor septa, with all 21 to 23 minor septa developed. Septa show spindle- shaped dilation as typical for the family, expanding laterally at the outer margin of the tabularium to oc- cupy % to ¥, of the space over the horseshoe dissepi- ments (PI.52, fig.1). Horseshoe dissepiments are them- selves heavily coated with stereome; thus the sleeve of horseshoes is clearly defined (P1.52, fig.3). Septa are complete and straight in the outer dissepimentar- ium, and abut straight, epithecal walls at a high angle. In oblique and longitudinal sections, rhipidacanth septal trabeculae can be seen forming tight symmet- rical fans over the vertical row of uniform horseshoe dissepiments. Stereome thickens these dissepiments on both the inner and outer side. Mature, large diameter corallites have four to six rows of flattened normal dissepiments in the outer dissepimentarium, but sev- eral smaller individuals have only a single row of flat dissepiments. One corallite has two rows of “normal” dissepiments, then one row of flat dissepiments at its periphery (PI1.52, fig.2). Tabulae tend to be irregular to almost complete and form a flat base to the calicinal pit. Most commonly there are large incomplete tabu- lae, inclined adaxially, located at the periphery of the tabularium. Discussion.—This single colony is placed in the ge- nus Trapezophyllum, since the dissepimentarium is variable, and not dissimilar to that illustrated from top- otypes of the type species of the genus by Hill (1981, p. F284). The subphacelloid nature of the uppermost corallites of the colony is regarded as an ecologic re- sponse to rapid sedimentation, which finally caused the death of the colony. The Iowa colony of Trapezophyllum does not close- ly resemble the undescribed species of the genus in the Frasnian Martin Limestone of Arizona (McLean and Sorauf, 1989, p. 390). The latter has more closely packed corallites, and has a uniform ladder-like con- figuration of outer, flat dissepiments at the periphery of the corallite, external to the row of horseshoe dis- sepiments. Other Frasnian colonial phillipsastreid corals with a truly cerioid colonial form are placed in the genus Smithicyathus Rozkowska, 1980. These are known from late Frasnian strata in the Northwest Territories of Canada (S. cinctum [Smith]) and in Poland (S. lub- liensis Rozkowska). The former is a species with very small-diameter corallites and strikingly aphroid septa within cerioid walls, while the latter is somewhat larg- er, but with short septa likewise separated from the walls by a lonsdaleoid dissepimentarium. Occurrence.—tThe single colony of this species col- lected came from float covering the basal, shaley beds of the Mason City Member in the abandoned quarry northwest of Marble Rock, Iowa (Locality 23, Appen- dix). It most likely came from the upper Mason City beds at this locality, where two colonies of Pachy- phyllum minutissimum were collected. Genus MACGEEA Webster, 1889 Prerorrhiza Ehrenberg, 1834, p. 312 (nomen oblitum); Pickett, 1967, p. 27: Birenheide, 1969a, p. 42; Birenheide, 1969b, p. 121; Bir- enheide, 1978, p. 108; Hill, 1981, p. F286; Birenheide and Soto, 1992 Spee lille Macgeea Webster, 1889b, p. 710; Fenton and Fenton, 1924, p. 53; Lang and Smith, 1935, p. 552; Stainbrook, 1946, p. 419; Roz- kowska, 1953, p. 18; 1956, p. 288; 1957, p. 102; Schouppé, 1958, p. 220; Stumm, 1962a, p. 161; Schouppé and Stacul, 1963, p. 266; Schouppé and Cheng, 1969, p. 171; Brice and Rohart, 1974, p. 47; Coen-Aubert, 1982, p. 14; McLean, 1984, p. 472; Sorauf, 1988, p. 172; McLean, 1989, p. 244; Coen-Aubert and Wrozelek, 1991, p. 10. Pexiphyllum Walther, 1928, p. 128; Birenheide, 1978, p. 112; Mc- Lean, 1989, p. 245; Birenheide, 1990, p. 270. Trigonella Rozkowska, 1980, p. 24. Debnikiella Rozkowska, 1980, p. 25; McLean, 1989, p. 245. Rozkowskaella Wrozlek, 1987, p. 277. Type Species.—Pachyphyllum solitarium Hall and Whitfield, 1873, Lime Creek Formation, Upper De- vonian, Iowa. Diagnosis.—Corals solitary or with few buds, char- acterized by everted calice, with prominent septal ridg- es above lower collar of epitheca; radial septa with variation ranging to having septa in distinct quadrants. Major and minor septa with symmetrical fans of rhip- idacanth trabeculae and marked dilation of septa in inner dissepimentarium. Well-developed sleeve of horseshoe dissepiments located at axis of divergence of trabecular fans, with horseshoes commonly thick- ened by stereome or covered by stereome containing rhipidacanths from adjacent septa. Normal dissepi- ments are seen interior to, and less commonly exterior to, the row of horseshoe dissepiments, with peripheral development of flat dissepiments. Septal ridges present on upper part of corallum, representing polypal edge zone above epithecal sheath. Discussion.—The synonymy provided above shows modern usage. Since 1967, a dichotomy has developed in the manner of usage of the genus name, but Mac- geea Webster, 1889 is properly used, rather than Prer- orrhiza Ehrenberg 1834. The name Pterorrhiza Ehren- 86 BULLETIN 355 berg 1834 was first mentioned for the second time in a faunal list by Sanford in 1939 (p. 409), more than 100 years later. It thus was a nomen oblitum. Lang et al. (1940, p. 111) were correct in regarding it as lapsed. They chose as lectotype of the type species, Cyathophyllum marginiferum, noted that it had been lost and stated that ““The genus therefore lapses’’. Pickett (1967, p. 27), utilized the name Pterorrhiza for the genus, as have Birenheide (1969a, p. 42, 1978, p. 108), Rozkowska (1980, p. 20), Hill (1981, p. 286), and Birenheide and Soto (1992, p. 111), regarding it as the senior synonym of Macgeea. This is incorrect, as the International Code of Zoological Nomenclature specifically requires that a nomen oblitum not be used without the Commission’s approval (1985, p. 175, ar- ticle 79c). Schouppé and Cheng (1969) rightly argued for suppression of the name Prerorrhiza; this was sup- ported by Pedder (1969) and by Pickett (1969) and opposed by Birenheide (1969b, p. 121). The Commis- sion has not acted on the matter. Following Article 79(c) of the 1985 edition of the Code, the name Mac- geea is used here. Extended discussions of the genus were provided by Schouppé and Stacul (1963, 1966) and Brice and Ro- hart (1974). The former provided an exhaustive sum- mary of previous work, skeletal structure and nomen- clature, and the latter authors presented an extended discussion of morphology and definition of the genus. Brice and Rohart (1974, p. 48) also noted that the ge- nus is characterized by a tripartite dissepimentarium with horseshoe dissepiments separating outer, flattened dissepiments from inner dissepiments that are axially inclined. They stated additionally that the genus is generally solitary, but that in some species, specifically Macgeea gallica, minor budding does occur in mature solitary corallites. Coen-Aubert and Wrzolek (1991) followed the definition of the genus of Brice and Ro- hart. They have defined two subgenera, based on the manner of development and persistence of horseshoe dissepiments. They defined Macgeea (Macgeea) as having horseshoe dissepiments in adult corallites, while Macgeea (Rozkowskaella) only has horseshoe dissepiments when immature (1991, p. 10). This basis for division of Macgeea into subgenera might be ques- tioned, but it does not affect the taxonomy of Lime Creek and Shell Rock corals, as all species present here fit well into the nominate subgenus. Schouppé had previously defined subgenera within this group on the basis of their solitary or colonial form, putting sol- itary corals in Macgeea (Macgeea) and fasciculate cor- als into Macgeea (Thamnophyllum) (1958, p. 226). Coral specialists all have since treated these two taxa as separate genera (Hill, 1981, p. F289). Birenheide (1978, p. 112) regarded the genus Pex- iphyllum Walther as separate from Macgeea (or Pter- orhiza,’ which he regarded as the appropriate genus name for the group). He placed most of the species described by Rozkowska (1953) as Macgeea into Pex- iphyllum, although noting that it is difficult to separate the two genera, but that Pexiphyllum is only typically developed in the Frasnian. Thus Birenheide apparently distinguished the the genus by its age. This grouping of Frasnian species of Macgeea into Pexiphyllum was not acceptable to Coen-Aubert (1982, p. 14), and is not acceptable to me. The genera Trigonella and Debnikiella were pro- posed by Rozkowska (1980, pp. 24 and 25, respec- tively). The former is based on a single specimen that is triangular in outline, and apparently lacking in horseshoe dissepiments in its mature stage (1980, p. 24), while the latter was based on one fragmentary coral also lacking a uniform row of horseshoe dissep- iments in its dissepimentarium. Since the former is a homonym of a bivalve species, Coen-Aubert and Wrzolek (1991) treated this as the subgenus Rozkow- skaella, a name substituted by Wrzolek (1987) for Tri- gonella, and placed Debnikiella into synonymy with Rozkowskaella (Coen-Aubert and Wrzolek, 1991, p. 10). McLean (1989, p. 245) had previously placed both Trigonella and Rozkowskaella into synonymy with Debnikiella. This does not involve the Iowa fau- nas, as all Macgeea species from Iowa are central to the genus and/or a nominate subgenus. An excellent review of European species of Mac- geea is presented by Brice and Rohart (1974), and spe- cies from Belgium are well defined by Coen-Aubert (1982). McLean (1989) has discussed the genus in western Canada, and Sorauf (1988) dealt with a New Mexican species of Macgeea. Distribution.—The distribution of the genus Mac- geea is virtually that of the cosmopolitan faunas of the Givetian and Frasnian, with diverse species reported from England, France, Belgium, Germany, Spain, Po- land and Russia in Europe, from the United States and Canada in North America and from Algeria in Africa, as well as numerous occurrences in Asia. Mac¢geea solitaria (Hall and Whitfield, 1873) Plate 52, figures 4—8; Plate 53, figures 1—23; Plate 54, figures 1-9, Plate 55, figures 1—5S Pachyphyllum solitarium Hall and Whitfield, 1873, p.232. Pl. 9, figs. 6-8. Macgeea solitaria Webster, 1889, p. 711; Fenton and Fenton, 1924, p. 54, Pl. 9, figs. 7-10; Lang and Smith, 1935, p. 552, text-figs. 10,11, Pl. 37, figs. 1-3; Smith, 1945, p. 27, Pl. 24, fig. 1; Stumm, 1949, p. 35, Pl. 17, figs. 1-3; Stainbrook, 1946, p. 420, Pl. 57, fig. 16, Pl. 60, figs. 11,14; Coen-Aubert and Wrzolek, 1991, p. 8, Pl. 1, figs. 1-3. DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 87 Pterorrhiza solitaria Pickett, 1967, p. 65, Pl. 5, figs. 19-21. not Macgeea solitaria Tsien, 1969, p. 70, Pl. 48, figs. 7,8,16. Diagnosis.—Variable, small- to medium-sized, sol- itary trochoid to subcylindrical corals with long, sub- radial major septa; characteristic tripartite dissepimen- tarium, generally with two to four rows of steeply in- clined internal dissepiments; well-developed and uni- form horseshoe dissepiments thickened by stereome, accompanied by marked septal dilation in the inner dissepimentarium, and with generally flat, but some- times irregular or globose peripheral dissepiments. Septal trabeculae rhipidacanths, forming tight, sym- metrical fans that are centered on the sleeve of horse- shoe dissepiments. Individual corals commonly have distorted base reflecting larval settling on hard sub- strate and molding to it. Description.—M. solitaria is a small- to medium- sized coral with an ovoid or angular, sometimes almost triangular cross sectional outline, in external view characterized by exsert septa exposed above very thin epitheca, which is commonly absent in rings around the exterior of the coralllite (P1.52, figs.4—8). The spec- imen figured by Hall and Whitfield was roughly tri- angular in outline (1873, Pl. 9, fig. 7), and this is shown by a number of other specimens (PI.53, figs.2,7,10). As in other species of the genus, the cor- allite is characterized by a calice with a deep, flat pit and septa standing high above the surrounding epithe- ca. The corals also commonly have a deformed base where larvae settled on, and conformed to, a hard sub- strate such as brachiopods, bryozoans or other corals. In transverse section M. solitaria ranges in average diameter from 9 to 22 mm, with a mean of 15 mm for 28 specimens. Adult diameters are mostly in the 18 to 22 mm range (Text-fig. 47). Septa are subradially ar- ranged and differentiated into major and minor orders, with a cardinal septum sometimes identifiable. Major septa number 27 to 38 in the 28 individuals noted above. Larger forms have 32 to 37 major septa. Major septa are long, reaching to the axis of the corallite or leaving a small open area (<4 mm). Septa either have an irregular trace in the tabularium, or more common- ly, may bend to swirl around a small axial open space. Major septa are dilated over the horseshoe dissepi- ments and are thin throughout the tabularium, some- times dilating slightly in the axial area. When an axial open space is present, this is elongate, thus parallelling the ovoid external shape of the corallite (P1.54, fig.7). Major septa of some corals extend to the axial plane of corallite elongation and stop there without joining (P1.54, figs.1,4). Minor septa are short, at most ex- tending only slightly into the tabularium and their in- ner margin is generally near the inner margin of the | A i t ! © 70+--------------l--| neotype }--—e<--+------ Jicdve=- z E 1 5) (nae) See a ee i a ' H os ' ' Oya a ea ster 22 = , ' a 3 | | S = or eA Rt Ee ee aeons D ) ' 5 50+------- Lf----- 34 = a 72) ' 1 ' = { ' H Bast At 1 i ' ' ' 1 1 ! 1 ' ' 1 ! ' \ t ' | ' H 404 Ss t 0.8 1 1.2 1.4 1.6 ies 2 WD 2.4 Diameter of Coral (in cm) Text-figure 47.—Macgeea solitaria from the upper units of the Cerro Gordo (formerly called the “Spirifer zone”), diameter of cor- allite (in mm) plotted versus the total number of septa for each individual studied. The proposed neotype (U.S.N.M. 48449a) is in- dicated on the graph. row of horseshoe dissepiments, itself always thickened by the addition of stereome. It is usual to see inter- sections of two or three rows of steeply dipping dis- sepiments interior to the horseshoe row and lateral to the axial margin of the minor septa (P1.54, fig.6). In longitudinal section, the horseshoe dissepiments and fan of rhipidacanth septal trabeculae centered over the horseshoes are prominent features of the species. The tabularium is generally broad and filled with flat, usually complete tabulae, but is somewhat variable, often dominated by flat, very thick tabulae which oc- cur at regular intervals, with less complete, slightly sagging or slightly arched tabulae in between. In some specimens, every sixth or seventh tabula is greatly thickened by stereome (as in PI.55, fig.5). The dissepimentarium is dominated by the presence of a sleeve of horseshoe dissepiments, so that longi- tudinal sections have a row on each side of the tabu- larium. Horseshoes are variable in that both shape and size can change within individuals. When the horse- shoes are small, they tend to be very uniform in size and shape (PI1.55, fig.1), but when larger tend to vary much more in the arcuate nature of the dissepiment, in the position of the horseshoe relative to its neigh- bors above and below (PI1.54, fig.9), and in the size of the horseshoe as compared with its suprajacent neigh- bors (P1.55, fig.4). The innermost part of the dissepi- mentarium characteristically has normal dissepiments interior (axial) to the horseshoe dissepiments (PI.55, figs.4,5). These vary somewhat in number and in shape. They are steeply inclined or vertical and occur in two to four rows, depending on the length of the minor septa, as interior dissepiments occur only be- 88 BULLETIN 355 tween minor and major septa. External to horseshoe rows are additional dissepiments, which may be flat and appear as a series of ladder-like peripheral dissep- iments, or which may be globose and irregular, form- ing a more normal-appearing external dissepimentar- ium. These can also separate the ladder-like dissepi- ments from the rest of the outer corallite (P1.54, fig.5). Septal structure is typical for the genus, with a fan of coarse rhipidacanth septal trabeculae positioned with its axis of divergence centered over the horseshoe dissepiments. The rhipidacanths are directed laterally, as shown in transverse section, and contribute to the coating of the row of horseshoes seen in longitudinal section (PI1.55, fig.5). Type specimens.—Neotype USNM 48449a (here designated), neoparatypes are USNM 135374, 135381, 2273b, 78449d, 78449f, 32706a, 32706b and 32706d. Discussion.—Macgeea solitaria is a widely reported species of Frasnian corals. Illustrations of topotype specimens have been published by a number of au- thors: Fenton and Fenton (1924, pl.9, figs.7—10), Lang and Smith (1935, p. 552, Text-figs.10,11), Smith (1945, pl.24, fig.1), Stainbrook (1946, pl.57, figs.16; pl.60, figs.11, 14), Pickett (1967, pl.5, figs.19, 20), and Coen-Aubert and Wrzolek (1991, pl.1, figs.1—3). In none of these cases, however, has a population been studied or population variation evaluated. It has been known for a number of years that the holotype of the species was lost; a neotype is here proposed for the species (USNM 48449a; Pl. 52, fig.7; Pl. 53, figs.1— 3) There is a broad tabularium in this species, thus sep- tal dilation occurs in a peripheral position. This can be exaggerated by erosion of the peripheral part of the dissepimentarium, so that the horseshoe dissepiments appear to be positioned right at the periphery. Tabulae also vary. They can be complete and flat, irregular where interfered with by septa, or incomplete in in- dividuals with very long septa. Septal dilation can be extreme, so that at times septa touch each other lat- erally, or only leave a very small space for horseshoe dissepiments and stereome. This is also the area where septal rhipidacanths diverge from the axial plane of the septa, and appear in longitudinal thin sections as laterally directed, rounded rods, perpendicular to the plane of the thin section (P1.55, fig.2). The configuration of the outer dissepimentarium is reminiscent of the genus Trapezophyllum, in which dissepiments external to the horseshoe dissepiments may either be a series of flat, ladder-like platforms, or more irregular, as rows of somewhat more inflated dis- sepiments forming the platforms. This was not rec- ognized in the genus Trapezophyllum until Hill (1981, p. F284) restudied topotypes of the type species of the genus. The variation seen in M. solitaria, in which the outer diSsepiments (as seen in longitudinal section) most commonly are uniform and ladder-like or some- what irregular, or even replaced at some horizons by globular “normal” dissepiments, has not previously been described in Macgeea solitaria. This variation is often not easily seen, as weathering of specimens tends to remove the external dissepiments. Rapid lateral ex- pansion of the dissepimentarium (P1.54, fig.9; P1.55, figs.1,2) appears to be connected with the formation of multiple rows of normal external dissepiments, probably associated with the polyp expanding its base rapidly outward, perhaps to avoid smothering by soft sediment. Variation also occurs in horseshoe dissepiments. They may be developed as a relatively straight row of uniformly developed horseshoes, or may be a more irregular row; they may consist of dissepiments which vary in how arcuate they are and also vary somewhat in size. In the Iowa fauna, horseshoe dissepiments are almost invariably coated with stereome. This coating of stereome can be very heavy, and extend right on across the tabulae from one side to the other. In one specimen (PI1.55, fig.5), this is seen to occur at regular intervals within the corallite and perhaps is seasonal in origin. Macgeea solitaria varies greatly, so much that some individuals of the Iowa species can be found which resemble individuals of many other species of the ge- nus. Thus, it is extremely difficult to assess relation- ships between it and other species. The amount of vari- ation illustrated on Plates 53 and 54 make this point clearly. There are however, recognizable differences between M. solitaria and other Frasnian genera from other outcrop areas. M. gallica from the Boulonnais region of France and related species are larger than M. solitaria (approximately 35 mm maximum diameter versus 22 mm for the latter), and contain considerably fewer septa than the Iowa species. M. bathycalyx of Germany and Poland is characterized by short septa and complete tabulae, while M. dubia of the Boulon- nais is much smaller in diameter, with less than one- half the number of septa, thus both are easily distin- guished from the type species. M. multizonata of Po- land and Belgium has approximately the same diam- eter and number of septa as M. solitaria, but has con- sistent stereome thickening of the horseshoe dissepi- ments and a larger number of internal dissepiments than the latter. The occasional budding of adults, re- sulting in a smallish ““colony”’, with a long parent cor- allite and several small buds (Brice and Rohart, 1974, p. 53) is seemingly a major characteristic of the spe- cies M. gallica. Macgeea camplanulata of the Owen Formation dif- DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 89 fers from M. solitaria by its more numerous internal dissepiments, its common bilaterality and its dilation of septa in the axial region, where uniformly long ma- jor septa swirl around the corallite axis and are dilated at their tips. Occurrence.—The species was collected from the upper part of the Cerro Gordo Member of the Lime Creek Formation, and found at most localities where these beds outcrop. These were localities 27 and 27a, South Portland; 28, Type Lime Creek; 29, County Line Road North; 30, Bird Hill North; 31, Bird Hill; and 35, Rockford Brick and Tile Co. Macgeea camplanulata, new species Plate 56, figures 1—12 Diagnosis.—Small, straight to slightly bent, tro- choid solitary corallites with long septa reaching to the axis, and well-developed, steeply inclined internal dis- sepiments. Septa strongly dilated over row of horse- shoe dissepiments, with outer dissepimentarium vari- ously developed and generally only fragmentarily pre- served. Tabularium most commonly filled with irreg- ular complete and incomplete tabulae. Description.—Macgeea camplanulata generally has small corallites with an ovoid outline, with maximum lengths near 25 mm and maximum diameter, above the calicinal pit, of 22 to 25 mm. Some are more elongate than others, and do not show apical attachment scars; thus it appears that they lived unattached on the sea floor or partially buried. In transverse section, 11 specimens show a range in diameter of from 12 to 17 mm, with a mean of 15 mm, while for the same specimens, the total number of septa ranged from 46 to 72. The smaller corals with few septa are immature (Text-fig. 48). Diameters mea- sured on transverse thin sections generally do not re- flect the true size of these corals, as virtually all of them have undergone some unknown amount of ero- sion on the sea floor prior to burial. Thin epitheca and at least part of the weak outer dissepimentarium has been removed. Diameters here more accurately reflect the diameter of the corals as measured at the outside of the horseshoe dissepiments. These, thickened by stereome and more resistant to erosion then the weaker external dissepiments commonly form the outer sur- face of abraded coral specimens. Septa are long and uniformly dilated in the inner dissepimentarium over the horseshoe dissepiments as in other species of the genus. Variation in these two features is common, and dilation varies, thus septa are dilated to fill between Y, and 7, of the space over the horseshoe dissepiments. Length of septa varies slight- ly; major septa usually extend nearly to the axis where they may swirl, leaving a small open area, or they may nae ee Total Number of Septa t t ' U ' Se raat 12 14 16 18 0 2 4 6 8 10 Diameter - Coral, in mm Text-figure 48 —Macgeea concinnula n. sp. from the Nora Mem- ber, and Macgeea camplanulata n. sp. from the Owen Member, di- ameter of corallite (in mm) plotted versus the total number of septa for each individual studied. The holotype of each is indicated on the graph. extend right to the axis and join the other septa (P1.56, figs.1,3,6,7). When this happens, there commonly is a swollen tip to the septa. In one specimen, septa are joined at the base of the calicinal pit to form an axial boss. Minor septa are long, extending well beyond the horseshoe dissepiments, with intersections of four to five internal dissepiments seen between septa. The ar- rangement of septa is commonly somewhat pinnate (P1.56, figs.3,11), and in two of the specimens studied, the cardinal septum is short and more prominently di- lated than other septa are, with a weakly pinnate ar- rangement of other septa around the axial plane of the corallite. In longitudinal section, up to eight rows of steeply inclined internal dissepiments are noted, although the usual development is four or five rows (PI1.56, fig.9). One specimen had none in its younger portion, then only several rows in the mature part of the section; thus this feature seems related to age. Horseshoe dis- sepiments are somewhat variable, but always thick- ened by stereome. They may form a straight row of uniformly sized and uniformly arched dissepiments or these may be much less regular, especially in the most mature part of the corallite where many internal dis- sepiments are also developed. Erosion of these corals very commonly has worn away the more exterior part of the dissepimentarium so that outer dissepiments are not seen. Where some of these are present, they are flat and ladder-like, but at least in the young part of the holotype, the flat broad base is filled with a mul- titude of small, steeply dipping, subarcuate dissepi- ments. This appears analogous to the development of talons in other rugosans as a way to spread on a hard 90 BULLETIN 355 substrate, as evidenced by the impressions of brachio- pods or other shells in this early post-larval portion of the corallite. The tabularium is quite irregular, in part at least due to the interference of long major septa with the build- ing of tabulae. Tabulae are almost always incomplete, and may be flat or inclined, irregular, or together form a flat bottom to the calicinal pit. In one specimen, where septa were somewhat shorter and an open space was present at the corallite axis, there was developed a flat-topped, cap-like row of axial tabulae. Septal trabeculae are discrete, separate rhipidacanths (P1.56, fig.10). Type Specimens.—Holotype SUI 3490, paratypes PRI 44826, 44827, 44818. Discussion.—M. camplanulata of the Owen is sim- ilar to M. solitaria in size and in general shape, but has a much greater development of internal dissepi- ments and fewer and longer septa than does the latter. Since M. solitaria is highly varied in many character- istics, however, it is possible to find resemblances be- tween individual corallites. In its development of a multitude of internal dissep- iments, M. camplanulata resembles several species seen in western Europe, especially M. gallica gigantea Brice and Rohart, 1974, and M. multizonata Read, 1922. M. gallica is much larger, with more internal dissepiments and has a greater number of septa (Brice and Rohart, 1974, p. 56) and M. multizonata is char- acterized by a consistent development of normal dis- sepiments in the interior part of the external dissepi- mentarium, inside the flat dissepiments at the periph- ery of the corallites (Coen-Aubert, 1982, p. 15). Occurrence.—This Macgeea species is common in the Owen Member. It occurs along with Pachyphyllum crassicostatum in the upper part of the member, in the so-called ‘“‘Acervularia zone”, the uppermost beds of the member. Belanski collected the holotype in Owen Grove (Locality 26, Appendix). In the present study it was collected at Lillibridge Quarry (Locality 38), Buseman Quarry (Locality 40), North Buseman Quar- ry (Locality 40A), and Morgan Quarry (Locality 39). Etymology.—This name was on a label in the Be- lanski collection, without explanation. Macgeea concinnula, new species Plate 57, figures 1-11 Diagnosis.—Small, cylindrical to medium-sized, ceratoid corals of the genus with short, very heavily dilated septa; complete or incomplete flat tabulae, somewhat non-uniform row of greatly thickened horseshoe dissepiments. Internal dissepiments few or lacking, and variable external dissepimentarium with flat, ladder-like peripheral dissepiments. Occasional corals have irregular dissepiments. Description.—M. concinnula is composed of cor- allites with an external shape varying between two ex- tremes, one with a small diameter, straight sides and cylindrical shape, and the other with a larger diameter and slightly ceratoid shape. Their diameters range from 7 to 17 mm in 16 specimens available for study, with a mean of 11 mm. Septa range from 38 to 58 with a mean of 47.1 in the same 16 individuals (Text- fig. 48). Septa are short, and major septa generally do not extend far into the tabularium. It is typical for cor- als in this species to have an axial open space of , to Y, the diameter of the tabularium, with straight septa terminating in the tabularium without swirling around the axis (P1.57, figs.1,4). Septa are very heavily dilated at the horseshoe dissepiments, and this may form a uniform collar around the tabularium (P1.57, figs.8,9). Cylindrical corals have smaller diameters (7 to 11 mm), a small number of septa (36 to 46), and all have a complete collar of stereome around the inner tabu- larium, formed of dilated septa and stereome coating, while those corallites with somewhat larger diameter (11 to 17 mm), may have more numerous septa (50 to 58), which are less dilated but may have very heavy coating of stereome restricted to the inner side only of the horseshoe dissepiments. Some specimens have a complete wall of stereome, which coats both septa and the internal flank of the horseshoe dissepiments. Minor septa are very thick also, but barely extend into the tabularium. In longitudinal section, the species is distinctive in its complete, flat or sagging tabulae and accessory, in- complete tabulae. Typically, the species has a flat-bot- tomed tabularium, with tabulae sometimes complete, thin, and widely spaced (PI1.57, fig.8). Internal dissep- iments are generally few and can even be missing, so that the transition from tabularium to dissepimentar- ium is very abrupt. One specimen, however, has the singular development of numerous normal dissepi- ments occurring inside, and almost merging with, the horseshoe dissepiments which are themselves rather ir- regular (P1.57, figs.3,11). Horseshoe dissepiments usu- ally form an orderly sleeve of uniformly sized, arcuate dissepiments, but can also be irregular. One specimen shows these two conditions on opposite sides of the same corallite. External dissepiments are rarely pre- served as they are thin and easily eroded from coral- lites, but are well shown in the ladder-like configura- tion in one paratype (PI1.57, fig.9). In the immature part of one corallite, there is a marked development of nor- mal, arcuate dissepiments outside the poorly differen- tiated horseshoe dissepiments (PI1.57, figs.7,8). The oc- currence of these dissepiments, and also the great de- DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 91 velopment of very numerous internal dissepiments de- veloped in one mature part of another corallite shows the variability common both in this species and in the genus. In these specimens (as in other Lime Creek and Shell Rock material), the periphery of the corallite is commonly weathered so that the preserved outer mar- gin of the coral is either the horseshoe row or the internal dissepiments. Only in one specimen is the out- er portion of the dissepimentarium well preserved, and here the outer dissepiments are ladder-like (P1.57, fig.9). Rhipidacanth septal trabeculae form symmetrical fans within heavily dilated septa and in heavy stereo- me deposited over horseshoe dissepiments. Where di- lation and stereome are thickest, fans form continuous, dense coverings for horseshoe dissepiments (PI.57, figs.8,9,11). Type Specimens.—Holotype SUI 1257, paratypes SUI 1252, 1256, 1258, and 1275. Discussion.—This group of corals presents some- thing of a taxonomic dilemma, as the two extreme cor- allite shapes, taken by themselves, could be used to indicate separation of species. Cylindrical corals al- most invariably have a complete ring of dilated septa and stereome at the position of the horseshoe dissep- iments, and have fewer septa, perhaps as a result of their smaller diameter. Ceratoid corals almost invari- ably have a larger diameter and more septa than cy- lindrical ones, and in this larger coral, the dilated septa commonly do not form a solid ring around the tabu- larium. There is always a very heavy coating of ster- eome on the inner margin of the horseshoe dissepi- ments, and in both forms the minor septa almost never extend inside the ring of stereome. Again, in cylindri- cal forms the minor septa are generally (but not in- variably) hidden within the solid ring of dilation and stereome, and only extend an extremely short distance inside this sleeve. Accompanying this feature is a sharp boundary between the tabularium and dissepi- mentarium. Where there are short minor septa and a heavy collar of stereome, there usually are few or no internal dissepiments. There are exceptions to this gen- eralization. There apparently is a continuum in maxi- mum diameter, shape, and number of septa between corallites with cylindrical and ceratoid form; as a re- sult, both are placed within this species. The difference does not seem to be biogeographical, as both forms occur together within the uppermost part of the lower biostrome of the Nora Member. Some individuals are attached to solid substrate, generally another coral, and these developed in the greatly elongate cylindrical growth form while forms without signs of attachment most likely lay on the sea floor, and seem to have expanded their diameter more rapidly and have more septa. There are a number of species recognized in Europe that resemble M. concinnula. These are species such as M. carnockii Rozkowska (1953, p. 24), with short, heavily dilated septa, few internal dissepiments and a broad, open tabularium, or those with a small diameter and cylindrical external form. 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Yu, C.M., and Kuang, G.D. 1982. Late Middle Devonian rugose corals from Liujing, Heng Xian, Guangxi and their paleoecological significance. Nanjing Institute of Geology and Palaeontology, Bulletin, Academia Sinica, no. 4, pp. 241-278. [in Chinese with English summary] APPENDIX—FOSSIL LOCALITIES SHELL ROCK FORMATION Nora Springs, Iowa, 7.5’ Quadrangle 1. Quarry North of Keidle’s Bluff. C, NE Y,, SW ¥, Sec. 26, T.97N., R.19W., Cerro Gordo Co.; 0.3 km (0.2 mi) due north of Keidle’s Bluff on Shell Rock River. Nora and Rock Grove Members of Shell Rock Fm. lie unconformably on lower Cedar Valley units. 2. Weitsie’s Bluffs. Along Shell Rock River; Weit- sie’s Bluff locality of Belanski; W %, NE /,, Sec. 35, T.I7N., R.19W., Cerro Gordo Co., Conservation Park on east side of Shell Rock River. Nora Member lime- stones lie directly on lower Cedar Valley dolomitic sequence. 3. Bjorgason. Series of low outcrops along Shell Rock River, Bjorgason ‘‘Phase”’ of Belanski (1927, p. 36) SEM SER. Sec, 35,097 NeeRalLS Wa Eero Gordo Co., on west side of Shell Rock River. Nora and Rock Grove Members occur above brown dolo- mites of underlying unit of Cedar Valley. 4. Reed Creek. Low cliff of very fossiliferous lime- stones on west side of Shell Rock River, ““Reed Creek Phase”’ of Belanski (1927, p. 359); C, SE %, NW %, Sec. 1, T.96N., R.19W., Cerro Gordo Co. Lower Nora biostrome exposed along river bank with great multi- tude of corals present. Approximately 300 m northeast of riverside outcrop is section 4a, just down slope from fork in county road, presently poorly exposed but a clean outcrop in 1970 with both biostromes of Nora Member well exposed, along with overlying Juniper Hill Shale. 5. South Reed Creek. C west line, SE %, Sec. 1, T.JON., R.19W., Cerro Gordo Co., east bank of Shell Rock River, in wooded bluffs along river with both lower and upper biostromes of the Nora Member ex- posed from slightly above river level to bluffs, and approximately 0.8 m of Rock Grove dolomites ex- posed at river level. 6. North Nora Springs. NE corner, SE 4%, NE 1%, Sec. 12, T.96N., R.19W., Cerro Gordo Co., east bank of Shell Rock River, in banks along river. Both lower and upper biostromes of Nora Member exposed in bluffs above river. 7. North line, SW Y,, Sec. 7, T.96N., R.18W., Floyd Co., on south (western) bank of Shell Rock River, in north-facing banks of river. In 1968, exposures of both Nora biostromes as well as underlying yellow brown dolomites of Rock Grove Member were present, since greatly obscured by grading and slumping. 8. Nora Dam. Center, Sec. 7., T.96N., R.18W., DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 97 Floyd Co., on northwest edge of Nora Springs, with 1.3 to 1.7 m of uppermost Mason City Member lime- stones normally exposed below dam (old mill dam, with abandoned millrace north of present channel). 9. Nora Springs. Eastern Y,, SE /,, Sec. 7, T.96N., R.18W., Floyd Co., cliffs on east bank of Shell Rock River in Nora Springs, Iowa. This is the type locality of the Mason City Member of the Shell Rock For- mation. Total Mason City outcrops for 0.4 to 0.6 km (0.25 to 0.37 mi) on each side of, and under, highway bridge of U.S. 18, on west side of Nora Springs. 10. South Nora Springs. NE corner, SE /,, Sec. 18, and NW ',, NW ¥,, Sec. 17, T.96N., R.18W., Floyd Co., cliffs on south (right) bank of Shell Rock River, exposures of the Mason City Member, with faunas dif- ficult to collect because of steepness of outcrop and weathering rind on north-facing cliff. Rudd, Iowa, 7.5’ Quadrangle 11. Reference Section. N %, NE Y,, NE ¥,, Sec. 17, T.ION., R.18W., Floyd Co., abandoned quarry on what was the Sherman Buffalo Farm in 1968, largely over- grown in 1986, but adopted as reference section for Nora and Rock Grove Members by Koch (1970, p. 67). 12. Rudd. NW ¥,, SE ¥,, Sec. 13, T.96N., R.18W., Floyd Co., abandoned quarry and small outcrops along Flood Creek, 190 m north of railroad trestle over creek on west side of Rudd, Iowa. Clean exposures of both lower and upper Nora biostromes were available 1967-1970, but considerably overgrown and dumped on by 1986. Also, there is a small outcrop of lower Nora biostrome on west side of Flood Creek 50 m south of railroad trestle. Mason City SE, Iowa, 7.5’ Quadrangle 13. McEachron Quarry. SW Y,, SW Y,, NW ¥,, Sec. 20, T.96N., R.19W., Cerro Gordo Co., abandoned quarry previously known as McEachran Quarry (Koch, 1970, p. 88), on east side of county road 0.8 km (0.5 mi) south of Portland, Iowa, and on south side of the Winnebago River. Nora biostrome lies uncon- formably on lower Cedar Valley. 14. County Roads Quarry. NE corner, SE ¥,, SE /,, Sec. 36, T.96N., R.19W., Cerro Gordo Co., located be- tween forked roads just south of Winnebago River. Upper biostrome of Nora Member is exposed around 1—1.5 acre flooded quarry. Rockford, Iowa, 7.5’ Quadrangle 15. Old Rock Grove Mill. SE Y,, SW ¥,, NE /,, Sec. 20, T.96N., R.18W., Floyd Co., on east (left) bank of Shell Rock River, on north side of county road, below old foundation of Rock Grove Mill, 0.2 km (0.1 mi) SW of Rock Grove Cemetery. Approximately 2.9 m of Mason City beds overly lower Cedar Valley and are overlain by lower Rock Grove Member dolomites. 16. Tom Williams Quarry. SW Y,, SW Y,, Sec. 28, T.96N., R.18W., Floyd Co., large quarry presently (1986) being extended to occupy most of east half of approximately 20 acre tract on east side of Shell Rock River. This was operated (1986) as the Greene Bros. Quarry, but had been known for years as the Tom Wil- liams Quarry (Koch, 1970, p. 71). The lower biostro- me of the Nora, all of the Rock Grove and virtually all of the Mason City Member are exposed at this lo- cality. 17. Baumgardner’s Mill. C, SW ¥,, SW ¥,, Sec. 28, T.96N., R.18W., Floyd Co. on east (left) bank of Shell Rock River, along what was formerly the millrace of Baumgardner’s Mill, site of the “‘Baumgardner’s Phase”’ of Belanski (1927, p. 394) and Koch (1970, p. 73). This was a classic outcrop of the entire Mason City Member and much of the overlying Rock Grove Member. In 1986 this was in process of being covered over by stripping of quarry area to the east, with soil bulldozed into the millrace. 18. Kapka’s Farm. S %, NE ¥,, NW ¥,, Sec. 4, T. 95N., R.18W., Floyd Co. on south (right) bank of Shell Rock River, low wooded cliffs on what was formerly Kapka’s Farm (1970). This is locality 155 of Belanski (Strimple and Levorson, 1969, p. 270), approximately 2.4 km (1.5 mi) northwest of Rockford. Here 3 m of Mason City beds are exposed above the summer river level. 19. Cooper’s Bend. South line, SW %, SE 7, Sec. 33, T.96N., R.18W., Floyd County, on northeast (left) bank of Shell Rock River, and Cooper’s Bend locality of Belanski, with low cliffs of Mason City Member limestones in wooded section of shore. 20. West Rockford. SW Y,, NE ¥,, NW ¥,, Sec. 15, T.95N., R.18W., Floyd County, on north (left) bank of Winnebago River, immediately west of abandoned bridge abutment on south side of Rockford, 33 m west of new county highway bridge. Complete section of Nora Member is exposed, along with upper 1—1.1 m of Rock Grove Member. This is the ““Rockford Phase” of Belanski (1927, p. 352) and the Rockford section of Koch (1970, p. 74). 21. South of Rockford. Bulldozed and stripped area on west side of county road adjacent to (1967) bridge over the Shell Rock River approximately 5.6 km (3.5 mi) south of Rockford in the NE Corner, SE /,, NE”, Sec. 35, T. 95 N., R. 18 W. These were temporary exposures of the Upper Nora biostrome, with very abundant fauna at the base, overlying yellow Rock Grove dolomites. 98 BULLETIN 355 Roseville, Iowa, 7.5’ Quadrangle 22. Roseville. SW corner, SE ¥,, Sec. 25, T.95N., R.17W., Floyd County, on north side of county road. Low outcrop of approximately 1.6 m of Mason City Member overlying lower Cedar Valley unit. This is the Roseville ‘“‘Phase”’ of Belanski (1927, p. 356) and the Roseville outcrop of Koch (1970, p. 75). It was well exposed in 1967 and 1968 but largely covered by 1986. 23. Marble Rock Quarry. Abandoned quarry on the north side (left bank) of Shell Rock River approxi- mately 1.6 km (1 mi) upstream of Marble Rock, Iowa. Quarry is in SE ¥, NW Y,, Sec. 8, T.94N., R.17W., where complete section of Mason City limestones overly lower Cedar Valley unit. Marble Rock *‘Phase”’ of Belanski (1927, p. 354). 24. Maxson Quarry. Active (1986) quarry in SE Y,, SE Y,, Sec. 7, T.94N., R.17W., Floyd County, slight- ly more than 1.6 km (1 mi) west of Marble Rock, on south (right) shore of Shell Rock River. This section has been described by Bunker, Witzke and Day (1986, p. 41). Approximately 3.8 m of the Mason City beds are exposed above the Lithograph City Formation, placed in the Cedar Valley Group by these authors. LIME CREEK FORMATION Hanford, Iowa, 7.5’ Quadrangle 25. Owen Grove West. North banks of Big Gully in pasture occupying NE /,, SE /4, Sec. 36, T.96N., R.20W., Cerro Gordo County, Iowa, and along Owen Creek. Outcrops of Acervularia beds of Owen Member outcrop sporadically in pasture. This is at the west edge of what was once commonly known as Owen Grove. 26. Owen Grove. In Owen Grove itself, best ex- posed are the Acervularia beds in abandoned quarry in NE ¥,, SW ¥,, SW Y, Sec. 31, T.96N., R.19W., Cerro Gordo County, Iowa. Outcrops also are present along south bank of Owen Creek in Big Gully, in SW Y,, NE ¥,, SW Y, of Sec. 31, but are of lower rocks of Owen Member. Rocks of upper Cerro Gordo Member are exposed in north bank of creek at approximate center ofiSec., silt Mason City SE, Iowa, 7.5’ Quadrangle 27. South Portland. Outcrops on both north and south sides of county road, with exposures along drainage ditches (which were clear and fresh in 1967 & 1968, but largely covered over by 1986) along boundary line in NE corner, NE Y,, Sec. 31, T. 96N., R.19W., in Cerro Gordo County, Iowa. The upper part of the Cerro Gordo Member, the “‘Spirifer’ beds of Fenton and Fenton was completely exposed in 1967, along with the upper part of their “‘striatula zone’’. 27a. In roadside exposures 0.5 km (0.33 mi) south of locality 27 could be seen outcrops of the same **Spi- rifer zone”’ of the Cerro Gordo Member, including the same rusty bed with colonial corals at the base of the “Spirifer zone’’, above the plastic clay of the ‘‘Dou- villina zone’. Outcrops were along the west side of the paved road, 4 km (2.6 mi) due south of Portland, in the SE corner, SE Y,, NE Y,, Sec. 31, T.96N., R.19W., Cerro Gordo County. 28. Type Lime Creek. The ‘‘Claybanks’’ County Conservation Park, bluffs on south (right) bank of the Winnebago River, 4.8 km (3 mi) downstream from Portland, Iowa. This is the type locality of the Hack- berry Stage of Webster (1887), and of the Lime Creek Formation (Calvin, 1897). The river called Lime Creek in Calvin’s time had a name change to Winnebago Riv- er prior to the 1920’s. The type locality is located in the NE ¥,, SE Y,, NE Y, of Sec. 34, and extends into the SW 1/4, NW ¥,, Sec. 35., T.96N., R.19W. The out- crop was fairly clean and 70% exposed in 1968, but presently is largely matted over with mud. This area is an eastward extension of the wooded area previously known locally as Hackberry Grove. Lime Creek beds exposed here in 1970 ranged from the Juniper Hill Member at and above river level, extending up through the entire Cerro Gordo Member, to the basal part of the Owen Member, exposed high in a southward-trend- ing gully south of the “‘claybanks” in the SE Y, of the NE Y, of section 34. 28a. West Hackberry Grove. Approximately 0.6 Km (0.4 mi.) west of the type Lime Creek section in Claybanks Conservation Park, these poor outcrops of the Cerro Gordo Member with float from the Owen occur in the SW Y,, NE Y,, Sec. 34, T.96N., R.19W., along the east face of a southward trending gully trib- utary to the Winnebago River. 28b. Lime Creek East. East and southeast of the type section of the Lime Creek Formation, two plowed fields have yielded abundant colonial corals from the ‘“Spirifer’ beds of the Cerro Gordo Member. The more northwesterly situated field is in the NW Y,, SE V,, NW Y,, Sec. 35, and the more easterly one in the NE corner, NW Y,, SE Y,, Sec. 35, T.96N., R.19W. In both fields plowing brings abundant corals to the sur- face each spring. 29. County Line Road North. Outcrops along North-South county road situated on the Cerro Gordo— Floyd County line, along the east line of the SE ,, NE Y,, Sec. 1, T.95N., R.19W., are of the Cerro Gordo Member of the Lime Creek, with the basal bed of the Owen Member exposed at the summit of the north facing hill, the escarpment of the Cerro Gordo and Owen Members. The roadside ditches, freshly cleaned out and highly fossiliferous in 1968 and 1970 were DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 99 much overgrown and apparently devoid of fossils in 1986. 30. Bird Hill North. Situated 2 km (1.3 mi) due south of Locality 29 are low exposures of the Cerro Gordo Member, situated in roadside ditches, along the east line of NE Y,, SE Y,, Sec. 12, relatively clean and richly fossiliferous in 1968 and 1970, but overgrown and relatively unfossiliferous in 1986. These low out- crops, along with those at nearby Bird Hill were for- merly the richest known for solitary corals of the ““Spi- rifer’” beds of the Cerro Gordo. 31. Bird Hill. One of the most famous of the lowa Devonian collecting localities, situated on the east- west county road forming the south line of the SE Y, of Section 13, T.95N., R.19W. Cerro Gordo County, where straightening of the road led to cutting away of a bank of extremely fossiliferous Cerro Gordo beds. These have been heavily tramped and collected for the past 40 years or more, and in 1986 were largely cov- ered and overgrown, with fewer fossils available. This was the locality with most abundant rugose corals in the unit. 32. Bird Hill South. Along north-south road run- ning up Cerro Gordo escarpment 0.6 km (0.4 mi) southeast of locality 31, along center of east line, NE V,, Sec. 24, T.95N., R.19W. Cerro Gordo County. This formerly was an abundantly fossiliferous and relatively clean section of the Cerro Gordo Member, but in 1986 was considerably grassed over. 33. Bird Hill East. Roadside outcrop of Cerro Gor- do beds 1.6 km (1 mi) ESE of locality 32 along E line, SE ¥,, NE ¥,, Sec. 19, T.95N., R.18W., Floyd County. Rockford, Iowa, 7.5’ Quadrangle 34. Juniper Hill. NW corner, NE ¥,, Sec. 17, T.95N., R.18W., Floyd County, with sporadic natural outcrops of the Cerro Gordo Member. 35. Rockford Brick and Tile Co. Quarry. In disuse in 1986, located in S %, NW ¥, Sec. 16, T.95N., R.18W., Floyd County, on north side of paved east- west road southwest of Rockford, Iowa. This is justi- fiably the most famous Upper Devonian fossil locality in Iowa. The quarry which formerly had extensive stripped surfaces and freshly quarried faces provided renewed collecting areas each year, and hundreds of thousands of superb fossils were disseminated to col- lections throughout the world. The Brick and Tile Company is no longer in operation since the early 1980’s and the quality of outcrops has declined greatly and collecting pressure has greatly lessened the avail- ability of fossil faunas. The quarry formerly exposed a superb section of virtually all of the Juniper Hill and Cerro Gordo Members. Sheffield, Iowa, 7.5’ Quadrangle 36. West Rockwell. Formerly exposed were beds of most of the Owen Member, in an abandoned Quarry, now utilized as a dump by the town and in the process of being filled in; quarry situated in SW Y,, NW ¥,, SW Y,, Sec. 3, T.94N., R.20W., Cerro Gordo County, situated on east side of north-south U.S. Highway 65. 37. Linn Grove. Town park in Rockwell, where an old quarry in Linn Grove provides some overgrown outcrops of the Owen Member in NE /,, NW Y,, Sec. 10, T.94N., R.20W., Cerro Gordo County. 38. Lillibridge Quarry. Excellent and extensive ex- posures of the complete Owen Member in large quarry occupying most of the E 4, SW ¥,, Sec. 26, T.94N., R.20W., Cerro Gordo County, 5.6 km (3.5 mi) south and 1.6 km (1 mi) east of Rockwell, Iowa. Hansell, Iowa, 7.5’ Quadrangle 39. Morgan Quarry. 3.2 km (2 mi) west and 2.5 km (1.5 mi) south of Aredale, Iowa, in SW Y,, NW Y,, Sec. 1, T.92N., R.19W., Franklin County. This quarry, in 1986 partly overgrown, formerly provided excellent exposures of the lower 7, of the Owen Member. Dumont South, Iowa, 7.5’ Quadrangle 40. Buseman Quarry. Formerly operated by Greene Brothers, 7.6 km (4.8 mi) due south of Dumont, Iowa, on the west side of county highway in SE ¥,, SE ¥, Sec. 21, T.91N., R.18W., Butler County. This quarry formerly exposed a complete section of the Owen Member beds, but in 1986 was no longer active and was partially filled with water. A clean sequence of much of the Owen is still exposed here. 40A. North Buseman Quarry. Abandoned quarry 0.2 km (0.12 mi) north of the Buseman Quarry, where beds of the Owen Member were exposed. 41. Carrolus Quarry. Flooded in 1986. When ac- tive, exposed a complete sequence of the Owen Mem- ber beds, features good exposures above the water line in the SE Y,, SE ¥%,, Sec. 34, T.91N., R.18W., Butler County, 11.3 km (7 mi) south and 1.6 km (1 mi) E. of Dumont, Iowa. 100 Figure 1-10. BULLETIN 355 EXPLANATION OF PLATE 1 External Views, Frasnian Corals from Iowa ile Aun fWN 10. Tabulophyllum curtum n. sp., holotype, S-U.I 858, Belanski Coll., (Same as Plate 14, figs. 10,11), * 1. Uppermost Mason City Member. . Tabulophyllum n. sp. A., S.U.1. 643, Belanski Coll., Lower biostrome, Nora Member, 1. . Disphyllum floydense (Belanski), paratype, S.U.I. 2003 Belanski Coll., Uppermost Mason City Member, x 1. . Disphyllum iowensis n. sp., holotype, S.U.I. 213, Belanski Coll., Lower unit, Mason City Member, X 1. . Disphyllum conjugans Belanski, paratype, S.U.I. 1376, Belanski Coll., Uppermost Mason City Member, x 1. . Tabulophyllum mutabile n. sp., S.U.1. 1266, Belanski Coll., Middle unit, Mason City Member. (Baumgardner’s Mill, Locality 17, Appendix), * 1. . Hexagonaria oweni (Belanski), S.U.I. 471, Belanski Coll., holotype, Upper biostrome, Nora Member, (Rudd, Locality 12, Appendix), x 1. . Pachyphyllum gregarium, P.R.1. 44785, Upper biostrome, Nora Member, (South of Rockford, Locality 21, Appendix), * 1. . Tabulophyllum rectum Fenton and Fenton, P.R.I. 44701, Upper Cerro Gordo Member, (North of Bird Hill, Locality 30, collected by Calvin Levorson). * 2. Tabulophyllum ehlersi Fenton and Fenton, P-R.I. 44702, Upper Cerro Gordo Member, (North of Bird Hill, Locality 30, collected by Calvin Levorson). * 2. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 1 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 2 Figure DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 101 EXPLANATION OF PLATE 2 1-11. External view of Frasnian corals of Iowa 1—4. Charactophyllum nanum (Hall and Whitfield, 1873), upper Cerro Gordo Member, Lime Creek Fm., all from North of Bird Hill, Locality 30, collected by Calvin Levorson, all X 2. 1. PR.I. 44735, 2. PR.I. 44736, 3. PR.I. 44737, 4. PR.I. 44738. . Hexagonaria inequalis (Hall and Whitfield, 1873), paratype, RM.N.H. 26055 (same specimen as Plate 35, Figure 2), X 1. Upper Cerro Gordo Member, (Type Lime Creek Fm., Section 28, Appendix). . lowaphyllum johanni (Hall and Whitfield, 1873), EM.N.H. 25772, (Same specimen as Plate 4, Figure 4), X 1. Upper Cerro Gordo Member, Lime Creek Formation, (Type Lime Creek Fm., Locality 28, Appendix). . lowaphyllum johanni (Hall and Whitfield, 1873), EM.N.H.26053, (holotype of Strombodes marginatus Fenton and Fenton, 1924, illustrated by Fenton and Fenton, 1924, Plate XV, Figure 5), * 1. Upper Cerro Gordo Member, (Type Lime Creek Fm., Locality 28, Appendix). . Pachyphyllum woodmani (Hall and Whitfield, 1873). 8, P-R.I. 44795, Upper Cerro Gordo Member, X 2. Base was on a brachiopod shell, with a very long founding corallite prior to typical budding. 9, PR.I. 44796, x2. 10, P-R.I. 44797, x2. 11, PR.I. 44798, x 1. All are from the former Rockford Brick and Tile Co. quarry, Rockford, lowa (Locality 35, Appendix). 102 Figure BULLETIN 355 EXPLANATION OF PLATE 3 1-7. External views of Frasnian corals of lowa Pachyphyllum woodmani, FM.N.H. 26017 (same as external view in Fenton and Fenton, Plate 8, Figure 2, of ““Plesiotype’’), Upper Cerro Gordo Member, (Type Lime Creek Fm., Locality 28, Appendix), x 1. . Pachyphyllum woodmani, Upper Cerro Gordo Member, (Former Rockford Brick and Tile Company Quarry, Locality 35, Appendix), all x 1. 2. PR.I. 44799, 3. P.R.I. 44800, 4. PR.I. 44801. . Pachyphyllum crassicostatum Webster 1889, RM.N.H. 26030, (““Plesiotype’’ of Fenton and Fenton, 1924), Uppermost Owen Mem- ber, (Type Owen, Locality 26, Appendix), * 1. . Pachyphyllum crassicostatum Webster 1889, S.U.I. 3057, Belanski Coll., Uppermost Owen Member (West Hackberry Grove, Lo- cality 28A, Appendix), x 1. . Hexagonaria bassleri, P.R.1. 44765, Uppermost Owen Member, (Lillibridge Quarry, Locality 38, Appendix), = 2. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 3 PLATE 4 hits) BULLETINS OF AMERICAN PALEONTOLOGY, WOLUME DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 103 EXPLANATION OF PLATE 4 Figure 1-7. Iowaphyllum johanni (Hall and Whitfield, 1873) 1, 2. N.Y.S.M. 3720/1, holotype, 1. transverse of corallites with heavy septal crusts and large, irregular dissepiments, X 5; 2 longitudinal with heavy septal crusts around tabularium, x 5 3. N.Y.S.M. 3721/1, transverse of holotype of Smithia multiradiata with large corallites and widespread septal crusts and crests, x5: EM.N.H. 25772, transverse, specimen with light crusts and huge dissepiments, * 2. EM.N.H. 26053, holotype of Strombodes marginatus, transverse, illustrating large dissepiments, X 2. alle 6, 7. U.M.M.P. 8087, Paratype of Strombodes marginatus. 6. transverse, showing septal crests and very large dissepiments, * 2; 7. longitudinal of trabecular crusts thickest close to tabularium, x 6. 104 Figure 1-6. BULLETIN 355 EXPLANATION OF PLATE 5 Towaphyllumijohanni) (Hallvandiwihitheld 85/5) menses ese-ne-ae eee eee ene ee ee nee eee eo . U.M.M.P. 8087, paratype of Strombodes marginatus, transverse enlarged to illustrate septal crests, * 5. . PR.I. 44692, transverse of colony with septal crests and “walls”, * 2. . PR.I. 44693, transverse, with crests and large dissepiments, * 2. PR.I. 44694, transverse of specimen with very large dissepiments, X 2. PR.I. 44695, transverse, showing extremely large, irregular dissepiments, < 2. PR.I. 44696, transverse, with very widespread crusts, X 2. A-wWN— fo BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 5 PLATE 6 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 105 EXPLANATION OF PLATE 6 Figure Page 1S. Toran Aino ora? (Gall aie Yan, SS) gcse ceoucoooeue cob cecd boo UboomoonubooUGoandooU Uo Ouo DO OOS 31 1. PR.I. 44696, longitudinal, with septal crusts separated by large, uniform dissepiments, * 6. 2. PR.I. 44692, longitudinal of colony with extremely irregular dissepiments, * 2.5. 3. PR.I. 44694, longitudinal to show periodic development of crusts with “‘walls”” separating corallites, X 2.5. HSNO. TOAD PAGO FENG ANG ENG, IC poms cos aceaaog momo mb SpeD soo oud oud ooo OaEbGococ KO mOoUME OSE 34 4, 5. U.M.M.P 7834, holotype, 4. longitudinal with flat-topped tabulae and presepiments preferentially developed on right side, =< 2; 5. transverse, with small lonsdaleoid dissepimentarium, * 2. 6, 7. U.M.M.P 7835, 6. longitudinal of paratype with regular tabulae, X 2; 7. transverse, X 2. 8. U.M.M.P. 7836, longitudinal of paratype with amplexoid septa and preferential development of presepiments on convex side of corallite, * 2. 9, 10. EM.N.H. 26006, holotype of 7. erraticum, 9. longitudinal of marked expansions and contractions of dissepimentarium, X 2; 10, transverse, X 2. 106 BULLETIN 355 EXPLANATION OF PLATE 7 Figure Page [—Sslaoulophyllumirectum, Eentonjandshenton WO2As aew-omey ease Vega sack often t-feeiteer nena ee eed area te nee ee eee eee a 34 1, 2. PR.I. 44697, 1. transverse, x 2; 2. enlarged view of characteristic dissepimentarium, * 6. 3. P.R.I. 44698, transverse, illustrating typical “‘wall” on innermost presepiments, x 8. 4. PR.I. 44699, transverse, * 5. 5. P.R.I. 44700, longitudinal, * 2. 6—l6melabulophylumieniersii-entonsandeeentonel 924 gaeeaene eaten renee terete tenet tare i rer eee nt eee ee 35 6, 7. U.M.M.P. 7815, holotype, 6. transverse, x 2; longitudinal, * 2 8, 9. U.M.M.P. 7818, paratype, 8. longitudinal, x 2; 9. transverse, X 2. 10. U.M.M.P. 7823, paratype, transverse, X 2. 11, 12. PR.I. 44703, 11. transverse, X 2; 12. longitudinal, < 2. 13. P.R.I. 44704, longitudinal, * 2. 14, 15, 16. PR.I. 44705, 14. transverse, * 2; 15. longitudinal, * 2; 16. longitudinal enlarged with presepiments forming platform, X 5. PLATE 7 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 wen oe yy yay , Lane RL; “t ¥, Yi ee ral cee b: BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 8 Ga ee DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 107 EXPLANATION OF PLATE 8 I losstabulophylinmrotlndumabentonangubentOns, L924) Vie cgsy cue scn=) eves cic ere. ete reves silciis cleus ccitericustiesensits (enestewed-ael ate oe ViMen t= iloll one neat 36 wal ae BNSOng re a n a . U.M.M.P. 7838, holotype, 1. longitudinal, x 2; 2. transverse, X 2. . EM.N.H. 26004, paratype, 3. transverse, X 2; 4. longitudinal with flaring of upper part of corallite by expanding disse- pimentarium, x 2. EM.N.H. 26005, paratype, 5. transverse, * 2; 6. longitudinal with large presepiments, * 2. PR.I. 44706, longitudinal of specimen with extravagent development of presepiments, * 3. PR.I. 44707, 8. transverse, X 2; 9. longitudinal with preferential development of presepiments on convex side of corallite, x 2. PR.I. 44708, transverse, * 4. PR.I. 44709, 11. longitudinal, * 2; 12. transverse, * 2. PR.I. 44710, longitudinal, * 2. PR.I. 44711, 14. transverse, X 2; 15. longitudinal, = 2. PR.I. 44712, longitudinal, with preferential development of presepiments on convex side of corallite, 2. 108 BULLETIN 355 EXPLANATION OF PLATE 9 Figure Page 13s labulophyllumirotundum: Eentonyandikenton.. 1924 ey aeanye eer renee eo eenaeeeenec ae aae eeeaen ae 36 1. PR.I. 44713, enlarged longitudinal view to illustrate amplexoid septa and trabecular structure, * 10. 2. PR.I. 44711, longitudinal, enlarged from Plate 5, figure 6, to show thin, delicate nature of presepiments in shale matrix, * TD: 3. P.R.I. 44714, longitudinal, enlarged to illustrate configuration of trough surrounding tabularium, as seen in cross section, * Teck 4-9" Tabulophyllum*ellipticum® (Halltand Wi hittield 873) ence ee enero on oe nn eerie ena en te 37 4—7. U.S.N.M. 78624, Fentons’ neotype, 4. transverse, * 2; 5. longitudinal, x 2; 6. longitudinal enlarged to illustrate fine septal ey trabeculae, * 4; 7. transverse, enlarged to show cardinal area, * 4. PR.I. 44715, 8. transverse, ¥ 2; 9. longitudinal with recrystallized areas, * 2.5. PLATE 9 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 10 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 as BS Om s Mm S S 2 % DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 109 EXPLANATION OF PLATE 10 Figure Page 1—2: Tabulophyllum ponderosum Fenton and Fenton, 1924 ...... 2... 2 eee te ee ee ee eee 38 1, 2. U.S.N.M. 78623a, holotype, 1. transverse with cardinal area at bottom of photograph, * 1.5; 2. longitudinal, 1.5 5 Seni apulopRyliueiiar ODUStiTA He NtONT ANG PEM COM 924i rete eee ay oie!) el ede ae cdiet ieee fettete= eel eee eee eae te te eto Cea 39 All transverse sections oriented with cardinal area at bottom. 3, 4. U.S.N.M. 78632A, holotype, 3. transverse, X 2; 4. longitudinal of broad tabularium and preferential development of disse- pimentarium at left, * 2. 5,6. U.S.N.M. 78632, paratype, 5. transverse, X 2; 6. longitudinal with flat-topped tabulae, x 2. . U.S.N.M. 78444a, 7. transverse, X 2; 8. transverse of younger part of corallite, * 2. . EM.N.H. 26007, holotype, Tabulophyllum exiguum Fenton and Fenton 1924, here synonymized. 9. transverse with cardinal area at bottom, * 2; 10. longitudinal, with presepiments best developed on convex side, X 2. 110 BULLETIN 355 , EXPLANATION OF PLATE 11 Figure Page 1=6") Tabulophyllum)tongum Fentonvand Fenton 31924 rere ee este niin t= ost eee erent reels 39 1, 2. EM.N.H. 26011, holotype, 1. transverse, * 2; 2. longitudinal with marked peripheral gutter in tabularium, x 2. 3. U.S.N.M. 78634A, transverse of paratype, * 2. 4, 5. S.U.I. 3629B, 4. transverse of corallite with weak bilaterality, < 2; 5. longitudinal with tabularial gutters and fragmentary tabular segments draped over amplexoid septa, * 2. . U.S.N.M. 78634, transverse of juvenile stage in paratype, * 2. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 11 ‘ a ote 6% ey seeks SEAL — WReaso Sits enh BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 12 ClO/seccu, je eee DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 111 EXPLANATION OF PLATE 12 Figure Page les. (MAN T Og nD ONO enGl IE eis WEPLE eae anon p ee cacao nm eecucUbeoubaboonOcomcoo ooo D oO UDO maDOY 39 1. U.S.N.M. 78634, longitudinal of paratype, * 2. 2, 3. U.S.N.M 53183, 2. longitudinal, x 2; 3. enlarged to illustrate septal trabeculae, * 5. 4. PR.I. 44716, transverse of corallite with short cardinal septum, at bottom, * 2. 5. PR.I. 44717, transverse of specimen with slight bilaterality of septa, x 2.5. 112 BULLETIN 355 EXPLANATION OF PLATE 13 Figure Page ie Labulophyllum:tongum'Eenton:andskenton;, O24) ii -e. soreness creas seen che CE enon one eee rR ere 39 1. S.U.I. 3076-3, longitudinal, with amplexoid septa on prominent tabula above large open space in center of photograph, and with tabularial gutter at left side of photo, x 2. 2 lapulophylium: magnum Pentoncand Fenton) 924 ee enteric cic aie ie ici eae neice erence ene ene renee 41 2, 3, 4. EM.N.H. 26009, holotype, 2. transverse, * 1.5; 3. longitudinal, * 1.5; 4. enlarged longitudinal showing broad dissepi- mentarium, X 2.5. 5, 6. U.S.N.M. 78638, paratype, 5. transverse, X 2; 6. longitudinal, x 2. 7. S.U.I. 3632-2, juvenile with differentiated cardinal septum at bottom, transverse, in this case photographed from the underside, accounting for apparent difference from normal septal deflection, * 2. PLATE 13 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 a L PLATE 14 113 VOLUME BULLETINS OF AMERICAN PALEONTOLOGY, DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 113} EXPLANATION OF PLATE 14 Figure Page Ss fapulophy luminaries entoru and ren toms O24 verses) eters rae a iee ieee) eee ered fe fee elt tte teeta 41 1. S.U.I. 3621, longitudinal of large individual with broadly expanding dissepimentarium, * 1.5. 2, 3. PR.I. 44718, a very large specimen with remarkable expansion and contraction of dissepimentarium resulting from variable sedimentation, 2. transverse, X 1.5; 3. longitudinal with amplexoid septa and heavy tabulae related to expansions and con- tractions of lonsdaleoid dissepimentarium, x1.5. 4. S.U.1. 3621, transverse, illustrating growth increments within monacanthine septa, 25. 5. PR.I. 44719, transverse, illustrating (diagenetic) lamellar skeletal structures, X 25. 114 BULLETIN 355 EXPLANATION OF PLATE 15 Figure Page 1. Tabulophyllum magnum Fenton and Fenton, 1924 1. S.U.I. 3623, longitudinal, enlarged to show septal trabecular structure, * 10. 2-6. Tabulophyllum expansum Fenton and Fenton, 1924 Sean ae nee en ners, Ca Leiner oe ceinii cia Moicld cca oo Sens 43 2, 3, 4. EM.N.H. 26012, holotype of species, 2. transverse with cardinal area at bottom and prominent axial boss, * 1.5; 3. longitudinal, * 1.5; 4. longitudinal enlarged to illustrate septal structure, x 5. 5, 6. S.U.I. 3339, specimen collected by Belanski, transverse sections oriented so that cardinal is at bottom, 5. transverse, X 2; 6. transverse in juvenile part of corallite with clearly differentiated cardinal area, < 2. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 15 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 16 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 115 EXPLANATION OF PLATE 16 Figure Page [2 TATA hip ie Nee Rahn pec aden som n ose copy Sou uDOibiGo cD Dean Dopo Dod oUmGnsoucetcuacec ep boca soonBs 44 1, 2, 3. S.U.I. 2247, holotype, 1. transverse, high in corallite, just beneath calice, * 2; 2. transverse lower in corallite, showing amplexoid septa abutting tabulae, X 2; longitudinal with sediment infilling some presepiments and amplexoid septa based on tabulae, * 2. 4, 5. S.U.I. 1731, paratype, 4. longitudinal of corallite with sediment infilling skeletal space and resulting expansion of disse- pimentarium, X 2; 5. transverse showing short cardinal septum, X 2. 6, 7. S.U.I. 141, paratype, 6. transverse of large individual with large presepiments , < 2; longitudinal showing large, bulbous presepiments at right, x 2. 8, 9. S.U.1. 84745, paratype, 8. transverse of corallite (photographed from underside) with heavy outer wall, x 2; 9. enlarged view of wall with septothecal structure, < 9. 116 BULLETIN 355 EXPLANATION OF PLATE 17 Figure Page NE PHATE eee eens toc isis He orcad ooo Gere OU Oe Ooo Soon ome Gan oo he 44 1, 2. S.U.I. 431, paratype, 1. transverse, corallite with apparent cardinal area, * 2; 2. longitudinal with large intertabular spaces, < 2. 3, 4. PR.I. 44720, 3. transverse of corallite with large amount of sediment infilling skeletal openings, * 2; 4. longitudinal, * 2. SS Tabulophy lum reurtummine Sp: i005 sceys. © Soe < sual aeaean a esos ado ars 3 ee eeroter ee sise #14) eR eRe SRO eee 45 5, 6. PR.I. 44721, holotype, 5. transverse, showing compressed and indented left and upper side, * 1.25; 6. longitudinal with characteristic broad, arched tabularium, * 1.25. 7, 8. S.U.I. 707, paratype, an undeformed corallite, 7. longitudinal, x2; 8. transverse, X 2. 9. S.U.I. 1435, paratype, transverse of corallite expanding towards left, < 2. 10, 11. S.U.I. 853, paratype, 10. transverse of corallite growing on square object in lower right corner, X 1.5; 11. longitudinal with preferential growth toward left, * 1.5. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 17 PLATE 18 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 Sat se ——— = SS —~ ia ee DIDI: VA f Oy Pi =! DEVONIAN RUGOSE CORALS OF IOWA: SORAUF IIL7/ EXPLANATION OF PLATE 18 Figure Page as, SST GATTO ey Sth so an ee bBAS wed SUe 666 Dab on Hon OOO EU KONG UD RCH Oooo ome E someon saamasdcaoouad 45 1. PR.I. 44722, paratype, transverse of septal structure with very fine trabeculae and fibro-normal flanks, x 12. 2. S.U.I. 1435, transverse of septotheca, x 10. 3. PR.I. 44721, holotype, transverse, to illustrate growth lines in tangential section of dissepiment, x 10. Soy inn Sine [ESO ROH Ty Se ace eames eae eee bepoo ood Sob aso DeMOOcCUbODU nC OBO ROD HO dOSE SOHO CO dO OR DOE 46 4-7. PR.I. 44723, holotype, 4. transverse, X 1.5; 5. longitudinal, < 1.5; 6. transverse of juvenile portion of holotype, < 2; 7. transverse section, enlarged to show cardinal area with “ladder-like” intersections with dissepiments, * 2.5. 118 BULLETIN 355 EXPLANATION OF PLATE 19 Figure Page 1L=35 Labulophyllumlevorsont MASP coarse creeen tas sae yette, ates ss) sas cig ener eons eee Rene CMe en eM oe a Re en een a 46 1-3. PR.I. 44723, holotype, 1. transverse of fibro-normal, fine trabecular septal structure, X 12; 2. transverse of septotheca with some diagenetic modification in outer part of wall, X 12; 3. longitudinal of septal microstructure with fine trabecular and incremental growth, * 12. 4-10) Tabulophyllum'buccinum sn. sp 3 ceiecs, 6 BS oe ys Se oe A evens) oe eel NNER Nae evra 47 4, 5. S.U.I. 1282, holotype, 4. transverse, with few, very elongate presepiments, < 2; 5. longitudinal, x 2. 6, 7. S.U.I. 1255, paratype with little or no lonsdaleoid dissepimentarium, 6. transverse, X 2; 7. longitudinal, x 2. 8. PR.I. 44728, paratype with uncharacteristic large number of long septa, transverse, X 2. 9. S.U.I. 1033, longitudinal of lath-like increments to septotheca and septal trabeculae at right, x 15. 10. S.U.I. 1285, paratype, transverse of septotheca, * 15. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 19 PLATE 20 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 set af Gad =e Se we “i ide ty é t i DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 119 EXPLANATION OF PLATE 20 Figure Page 2 EAD LELOTILY LLATIEES De NNO Re gs Ee Lek ep PE ERS ag Mts eg sh Dea eM ease oltey ote esos cose) sc Sane sin Mey seus cee 48 1, 2. PR.I. 44729, 1. transverse of ovoid corallite with elongate presepiments, * 3; 2. longitudinal with amplexoid septa based on sparse tabulae, X 3. SECL VET ATO Sos 13) 5 oon sg bed OOO UMOdn GoW cone oon oot deoe Ee betos Fon b Wahoo DOS ano oOo Oo aoeminD 48 3, 4. S.U.I. 186, 3. longitudinal, with large presepiments, X 2; 4. transverse of corallite with arrow-like septa, thickest at presepimental wall, X 2. SSG Teg OTT ATUNT THOTT We Gob sob OR eee Gnas 5 dod AeaeniG hla nh at es old gid Dine mos bo esb hate. Go.n co's pers 49 5, 6, 7. S.U.I. 1291, holotype, 5. longitudinal, with complete, arcuate tabulae and few dissepiments, X 2; 6. transverse with short septa, X 2; 7. transverse, enlarged to show septotheca, 5. 8, 9. S.UI. 1250, paratype, 8. longitudinal, x 2; 9. transverse of corallite with long septa, * 2. 10. PR.I. 44730, paratype, transverse, X 2. 120 BULLETIN 355 EXPLANATION OF PLATE 21 Figure Page AS LarpiLYypPRYLUIn CY LNATICUIM NYSP. a-tiyiet tense eee eee er eee eee 49 1, 2. S.U.I. 1291, holotype, 1. transverse, enlarged of septothecal wall structure, * 14; 2. longitudinal, enlarged wall and septal structure, * 7. 3, 4. S.U.I. 1290, paratype, 3. transverse, X 2; 4. longitudinal, x 2. 8. PR.I. 44731, paratype, transverse, enlarged of wall and septal structure, x16. Sh, Os OS IDO DORN maa oneacunno boo meh nosadconmobbGasgoos GOD ob UD SON DU aeonoCosE oo OOHODO DOOD DOGS 50 5, 6, 7, 9, 10. S.U.I. 84748, 5. twinned juvenile, transverse, < 2; 6. adult transverse, x2; longitudinal of corallites with sparse tabulae, < 2; 9. transverse, enlarged to show slightly (diagenetically) modified wall and septal struc- ture, X 12; 10. longitudinal, enlarged to show wall structure and septal trabeculae, * 12. PLATE 21 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 M54 SAN Sze BR N oF PLATE 22 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 & : — WN oS, %j aS Ws = \\ Pd 1} yy : } e* S DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 211 EXPLANATION OF PLATE 22 Figure Page IEG OVPREL IAI LY LEELIMD LQTS ITAL COCK el OOD Le rautec eter eae a ch AMMEN eM SRV cee es Sylevel Sues ee SP eu welie oe kT eco eG ESE nee ee tes oer 1, 2. S.UT. 11616, holotype, 1. longitudinal, illustrating tabulae that are complete, flat or sagging, or incomplete and inclined, x 2; 2. transverse with short, thin septa and elongate presepiments, < 2. . S.U.I. 11617, paratype, transverse, with prominent presepiments, X 2. . S.U.I. 84749, transverse and longitudinal of topotype, < 2. 5, 6. PRI. 44732, 5. longitudinal, with irregular tabulae, X 2; 6. transverse with numerous buds, X 2. WwW 122. BULLETIN 355 EXPLANATION OF PLATE 23 Figure Page [San Smilniphy lum belanskiL Redden 965) a os sai eth reece eee Need eal ore Pee ae ote a ae 51 1. S.U.I. 11617, paratype, transverse, with stromatoporoid ground mass, * 8. 2. S.U.I. 11616, holotype, enlarged to show dissepiments and septal trabeculae, 15. 3. S.U.I. 84749, enlarged to show tabulae and presepiments, * 10. 4. PR.I. 44733, enlarged septotheca and short, spine-like septa, x 25. 5 . PR.I. 44734, longitudinal, with steeply inclined presepiments and variable tabulae, * 7. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE WwW PLATE 24 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 11723} EXPLANATION OF PLATE 24 Figure Page NaS. Clormam an atinie tan? (eel errl Wanita Gh ME) Gass e co ses ey sen ebooo SOB eR DO Odoog oC bond obo oan eecoEoOoD se 54 1. N.Y.S.M. 3160/1, longitudinal acetate peel print of holotype, < 2. 2. PR.I. 44739, transverse of individual with long septa dilated in tabularium, 2.5. 3-5. PR.I. 44740, 3. transverse of septal dilation, X 2.5; 4. longitudinal with complete, flat tabulae, x 2.5; 5. juvenile with swirled, dilated septa, X 2.5. Septa in this genus are swirled in a counter-clockwise direction when seen from above. Some photographs on this plate were photographed from below. 6-8. PR.I. 44741, 6. transverse, with septa dilated at axis to form boss, x 2.5; 7. longitudinal, * 2.5; 8. juvenile with very heavy septal dilation and short cardinal septum, 2.5. 9-11. PR.I. 44742, 9. transverse, X 2.5; 10. longitudinal with clearly flat-topped tabulae, x 2.5; 11. juvenile, with cardinal septum at bottom of photo, x 2.5. 12. P.R.I. 44743, transverse of corallite with thin septa, x 2.5. 13-15. PRI. 44744, 13. transverse, X 2.5; 14. longitudinal of corallite with numerous globose dissepiments, * 2.5; 15. juvenile, x 25- 124 BULLETIN 355 , EXPLANATION OF PLATE 25 Figure Page [12 Gharactophylluminanum) (Halland Whithield 1187/3) meat -eeestea- atc emen eh elec ea tree dante gan a de 54 1, 2, 3. PR.I. 44745, 1. transverse, X 2.5; 2. longitudinal, X 2.5; 3. juvenile, X 2.5. 4, 5, 6. PR.I. 44746, 4. transverse, X 2.5; 5. transverse, X 2.5; 6. transverse, * 2.5; sequence of sections in one corallite illustrating variation in lenth and dilation of septa. 7, 8. EM.N.H. 26002, Fenton *‘Plesiotype” of Zaphrentis solida, 7. transverse of corallite with knobby septa, * 2.5; 8. lon- gitudinal, * 2.5. 9. EM.N.H. 26003, Fenton “‘Plesiotype”, Zaphrentis solida, transverse of corallite with little dilated septa, * 2.5. 10-13. 10. PR.I. 44747, longitudinal, * 5; 11. PR.I. 44748, longitudinal, * 5; and 12. PR.I. 44749, longitudinal, x 4.5; series to illustrate variation in dissepiments and tabulae and to show pattern of bending in septal trabeculae. PLATE 25 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 26 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF Is) EXPLANATION OF PLATE 26 Figure Page lo Charactophyluminanists ralleandawinitieldemlouS) mmetm ier en ete tet eget oae Ree ateneye cl sn-tiayci ee ices eee nee eee Rem 54 1. PR.I. 44750, longitudinal of corallite with abundant globose dissepiments and heavy dilation showing septal structure with typical bending of trabeculae, * 5. 2. PR.I. 44751, transverse of individual with marked septal inflation in tabularium, (photographed from below), * 6.5. BOM isphylumidispassunn (henton and Menton, ml O24) immer meyers nen-e emis tctenes (-iioie) ern cyiehi oy cites femadiome (aytettelette lic mctieyt- Re iott-tt =e Meet 58 3. EM.N.H. 26045, holotype, transverse of corallite preparing to bud, x 3. 4. EM.N.H. 26014, holotype of Diphyphyllum tubiforme, oblique, * 3. 5, 6. PR.I. 44752, 5. transverse, showing variation in length of septa between corallites, X 3; 6. longitudinal with wide dissepi- mentarium giving rise to bud, * 3. 7. PR.I. 44753, transverse of corallite with long septa, < 3. 8. PR.I. 44754, longitudinal, with prominent, widely spaced, complete tabulae, x 3. 9. P.R.I. 44755, transverse of long-septaed form with buds, x 3. 0. P.R.I. 44756, transverse, with buds, x 3. Figure BULLETIN 355 EXPLANATION OF PLATE 27 l—S5 Disphyllumifloydensel (Belanskis1928) ie secede. = cys aces avs cs ees clays ick Tene See RRA een enn meee nem earn en ee ily Sh . S.U.I. 364, transverse of specimen with heavily dilated septa, * 2. . PR.I. 44757, transverse of corallites with long septa, some with lumpy trabeculae, * 4. . PR.I. 44758, longitudinal of corallite with axially inclined thick septal trabeculae and with irregular tabulae, * 6. nk w U.S.N.M. 710296, paratype 1. transverse, * 2; 3. enlargement of section to show corallites with typical septal dilation, x 4. PLATE 27 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 28 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF P27 EXPLANATION OF PLATE 28 Figure Page Ae Disphylurnsfloydense((Belanskas i928) ioe. oe: eyes ros 2h wos (e os hepa ae es Mev epbene sie aie= Beas: se hepete on e Megete ese tod teeta Tier oue) 2 59 1, 2. PRI. 44759; 1. transverse of typical colony, x 2; 2. enlarged longitudinal illustrating variable development of dissepiments and bulbous peripherial dissepiments, x 6. 3, 4. PR.I. 44760; 3. transverse of colony from southern (Marble Rock) area with large diameter corallites, x 2; 4. longitudinal illustrating peripheral large dissepiments, * 4. Sh, IDA SIUTED BOLUS De Fob 6-6 tudo GS Ne Clonee eae paar as in are oa clo cherie ONES a ita acini eb ole ie) Suede ote toe isiee Oks ona .otare 5, 6. S.U.I. 1625, holotype, 5. transverse, older; and 6. younger coralla with abundant budding, both x 5. 7. S.U.I. 1624, paratype, longitudinal, illustrating growth on fallen stromatoporoids, x 4. 128 BULLETIN 355 EXPLANATION OF PLATE 29 Figure Page 1=2 52 Disphyllum CONJUBANG MN: SPs Ryras,chs, Meds) Sas ee pe we Reed Ae SE ae Ed ATG) 3, Sage os REE oa oe rere 1, 2. S.U.I. 1376, paratype, 1. transverse of adult colony, * 3; 2. longitudinal, with outer row of large dissepiments,x 3. 920! Dis piayllUmMmiGWensis Ts SP poo iewesines a dare chs See, eee eee eae ee eee ROR RO Ee eae ey ene ree: 3, 4. S.U.I. 541, holotype, 3. transverse, with variable septa, partly crushed, 2; 4. longitudinal, with calicinal pit, * 3. 5, 6. S.U.I. 1626, paratype, 5. transverse, with long septa, X 5; 6. longitudinal, with large outer dissepiments, < 5. 7, 8. S.U.I. 1756, paratype, 7. transverse, with thin septa and open axial space, 2; 8. partly longitudinal, * 2. 9. S.U.I. 1509, paratype, transverse, with open axial space and heavy septa at wall, x 3. PLATE 29 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 30 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 129 EXPLANATION OF PLATE 30 Figure Page =O. RESTON Fal (OREM? Antal onions NAD, sos acanads tn owt aun oWahonnOoseconabonneonooe Gos ono Os Ae lnG 64 1. U.S.N.M. 78619, holotype—H. bassleri bassleri, transverse of colony, * 2. 2, 3. U.S.N.M. 78620, holotype—H. bassleri depressa, 1. transverse, showing smallish corallites, x 2; 2. longitudinal of corallite with calicinal pit, x 5. 4. U.S.N.M. 78621, paratype, H. bassleri bassleri, transverse, X 2. 5, 6. U.S.N.M. 78619, holotype of H. bassleri, 5. longitudinal, illustrating axial and periaxial tabulae as well as broad dissepimen- tarlum with numerous dissepiments, * 5; 6. transverse, with varied septal dilation, x 5. 130 Figure 1-6. BULLETIN 355 EXPLANATION OF PLATE 31 Hexagonaria bassleri (Webster and Fenton, 1924) 1. PR.I. 44761, transverse of colony with variable development of inflated septa trabeculae, x 2. 2. PR.I. 44762, transverse of colony with dilated septa, < 2. 3. PR.I. 44763, transverse, showing variable development of carinae-like structures in dilated septa, * 2. 4. U.M.M.P. 8085, paratype of H. bassleri, transverse, with “spindle-shaped* septal dilation, * 2 . 5. PR.I. 44764, longitudinal, to illustrate tabularium with axial and periaxial rows of tabulae and septal structure of inclined monacanthine trabeculae, x 10. 6. PR.I. 44762, longitudinal of dissepimentarium and inclined monacanthine septal trabeculae, x 10. PLATE 31 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 32 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 131 EXPLANATION OF PLATE 32 Figure Page IEP eX a2 ONGIarDaSSleril(WeDStectzanGiEeuton mlLO24) eee rants ee ieee eps |. esas ey sp oh coke ead cures. oun cece Tee el ieee eu cte = 64 1. PR.I. 44763, transverse, enlarged to illustrate incomplete septa and enlarged dissepiments prior to budding (arrow) and carinae- like structures in septa resulting from enlarge septal trabeculae, < 8. 2-5. Hexagonaria bassleri magna (Webster and Fenton, 1924) 2-5. U.S.N.M. 78637, holotype of H. bassleri magna, 2. transverse of colony with very large corallites and variable but heavy septal dilation, X 2: 3. longitudinal, < 2; 4. longitudinal, enlargement of single corallite to illustrate tabulae, septal structure, and broad dissepimentarium with banding evident, 4; 5. transverse of large corallites and “carination” of septa, 5. 132 BULLETIN 355 EXPLANATION OF PLATE 33 Figure Page 1. Hexagonaria bassleri magna (Webster and Fenton, 1924) 1. U.S.N.M. 335007, transverse of colony with typically large corallites, * 2. 2-5. Hexagonaria oweni (Belanski, 1928) 2. S.U.I. 471, holotype, transverse and oblique, x 2. 3. PRI. 44766, transverse of typical colony with septal dilation in inner dissepimentarium, * 2. 4. PR.I. 44767, transverse of colony with light skeleton, * 2. 5. PR.I. 44768, transverse of colony with local heavy dilation of septa and walls, * 2. PLATE 33 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 {2 err 1pRbhee f \—3 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 34 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 133 EXPLANATION OF PLATE 34 Figure Page LR eT CXAPONALIATOW ENts (BCLANSKIS 1.92.8) sare) Gare ss oeiroa shan Areva de os iat oben ee siee sete Revaisy eh 33, Sos She sy Saw oe Sasicue uci Gre, Acre cay et asteyiee atest gues aes 67 1. U.S.N.M. 71041, paratype, longitudinal of corallite with typical tabularium and numerous dissepiments, * 6. 2. P-R.I. 44769, transverse, enlarged to illustrate swollen septal trabeculae and “‘carinae”’, X 6. 35 eXOcOnaniaiuiequalts) (Kallvand swWihithield sl 87S) meee ctcdens tore ve reece eirauoi=t eNe t-tiet Suche eeienen a eitetare ateeette euesel inte cafeus yore lelene ve 68 3. N.Y.S.M. 3000/1, holotype of H. inequalis, transverse of specimen with small corallites and considerable septal dilation throughout, * 5. 4, 5. U.S.N.M. 78635, Fenton and Fenton illustrated specimen (1924, Pl. 14, fig. 7), 4. longitudinal of corallite with typically incurved septal trabeculae and axial and periaxial rows of tabulae, * 7; 5. transverse of corallum, * 2. 134 BULLETIN 355 EXPLANATION OF PLATE 35 Figure 1-5. Hexagonaria inequalis (Hall and Whitfield, 1873) U.M.M.P. 5319, holotype, H. whitfieldi, transverse of colony with broad dissepimentarium and elongate septa, * 2 EM.N.H. 26055, paratype, H. whitfieldi, transverse of colony with narrow dissepimentarium, * 2. PR.I. 44770, transverse of large diameter specimen, * 2. PR.I. 44771, transverse, showing corallites with narrow dissepimentarium, < 2 PR.I. 44772, transverse of small diameter specimen with dissepimentarium of variable width, x 2 WN we PLATE 35 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 36 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 135 EXPLANATION OF PLATE 36 Figure aa Hexavonariannequaus (all andy Whithelds 1873) ccs sien ccc crsesees acsh esi on a. os: ah syd site; erie ay e,couleueesutey ee! aba, a)eusiieiiaus es are aeons eee 1. PR.I. 44773, transverse of corallum with small diameter corallites, * 2. . PR.I. 44774, longitudinal, showing characteristic inbending of monacanthine septal trabeculae, x 9. B 3. EM.N.H. 26048, Webster and Fenton “Plesiotype” of H. inequalis, transverse of small colony resembling holotype of H. inequalis, X 2. 4. P.R.I. 44775, longitudinal, with characteristic axial and periaxial rows of tabulae, x 9. 5. Pachyphyllum minutissimum Webster, 1905 5. U.S.N.M. 78648, holotype, transverse of corallum with small corallites and marked septal dilation at outer border of tabularium, * 2 136 Figure 1-6. Pachyphyllum minutissimum Webster, 1905 1. nAkwWhN BULLETIN 355 EXPLANATION OF PLATE 37 P.R.I. 44776, transverse of colony with very small diameter corallites, * 2 U.S.N.M. 78624, holotype, longitudinal, with typical complete tabulae and horseshoe dissepiments, * 7. PR.I. 44777, transverse, corallites with large diameter, * 2. PR.I. 44778, transverse, small colony with strong septal dilation, * 2 PR.L. 44779, transverse, small diameter corallites with heavy dilation and long septa, corallites aphroid in part, * 5 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 A # 3 =i G SX ees) ae. V * es Ve ps Qa * i PRs ea i ps? Ae ee ar yO GK : = ZAM yo ro ’ ag ( wee vy s Ry by Wy = sth BE CES, & Cy A Ki 2D Bays he i WS Se PLATE 37 PLATE 38 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 AW ae 72 eee ON hey wn we “é ¥ i! SEES r 4) fey Sg, 4 ae St DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 337/ EXPLANATION OF PLATE 38 Figure 1=6.) PachyphyllumimernulissimurmawWebster 1905) alee eee ee es ee oo) el ee) lel etl ee tee eee) 2m eto et a) eee el le 73 1. PR.I. 44780, transverse of small diameter corallites with marked dilation of septa, * 5. PR.I. 44781, transverse of typical small colony from Nora Springs Dam, x 2. PR.I. 44782, transverse of large corallites with some confluency between individuals, * 5. PR.I. 44783, longitudinal, enlarged to show horseshoe dissepiments and fans of septal trabeculae, X 8. PR.I. 44784, transverse, illustrating budding in colony, X 8. PR.I. 44781, longitudinal, illustrating horseshoe dissepiments and septal structure in dissepimentarium, X 9. Why Oyu 138 BULLETIN 355 EXPLANATION OF PLATE 39 Figure 15: Pachyphyllumisregarium Webster) 1905) rey. oie) cere ee ieviata et octave Ute tal) oleent (ote eyed eel ete ee oN 1, 2. U.S.N.M. 78645, lectotype, 1. longitudinal, with seasonal(?) banding shown by size of dissepiments and spacing of tabulae, < 2; 2. transverse illustrating slightly aphroid nature of corallites, * 2. 3, 4. U.S.N.M. 78645A, lectoparatype, 3. longitudinal, with complete, flattish tabulae, < 2; 4. transverse of colony with aphroid corallites in center, * 2. 5. U.S.N.M. 78645, longitudinal of portion of lectotype showing typical tabularium and somewhat irregular development of row of horseshoe dissepiments, * 6. PLATE 39 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 e a 2 ae : %* , > s wt, a BOOS EAE RY + ‘ ay a PLATE 40 Figure PACRYPRYUUTMCTERATIUIMEW CDSLCE FLOOD war terete oe pet ee te ecere ea OLS, ete eee ws eU NL Seep tise Rola ere Ree eee Oe Fen eet eee ns 75 1-5. WN ues PRL. PRI. PRI. PRI. PRI. 44786, 44787, 44788, 44789, 44790, DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 139 EXPLANATION OF PLATE 40 transverse, corallites with dilation of septa over uniform collar of horseshoe dissepiments, * 5. transverse, corallites with heavy dilation of septa and indistinct walls between individuals, * 5. transverse of dilated form, * 5. transverse of individuals with light dilation of septa and aphroid nature of colony, * 5. longitudinal, corallite with uniform horseshoe dissepiments, no internal dissepiments, and complete tabulae, x 5. 140 BULLETIN 355 EXPLANATION OF PLATE 41 Figure Page l=dsPachypryliumiwebstert Belanski, 1928) 0.02 ieee see ence tel che etic ae honest asthe Ren Rented oom ee eee en 1. S.U.I. 2176, holotype, longitudinal, illustrating tabulae and large, irregular dissepiments in large corallites, 2. 2, 3. U.S.N.M. 71030, paratype, 2. transverse and longitudinal of colony with rapidly diverging corallites, with occasional occur- rence of large, irregular dissepiments, * 2; 3. longitudinal, enlargement with typically irregular tabulae, horseshoe dissepiments and varied outer dissepimentarium, * 4. 4. S.U.I. 729, paratype, transverse with longitudinal sections of rapidly diverging corallites, < 2. PLATE 41 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 42 e ® oe A a. ~e DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 141 EXPLANATION OF PLATE 42 Figure Page LO LACh phy lume eDSIeria BelanSkiwlo 2 Sipe ceri este pee) See ore See ee Cae eT ea vee eae se one a nee ep eraers eater cs 76 1. P.R.I. 44791, transverse, of large, somewhat aphroid corallites with characteristic dilation of septa, * 2. 2. PR.I. 44792, transverse of large corallites with budding, * 4. 3. S.U.I. 2176, holotype, longitudinal, illustrating irregular flat tabulae, uniform row horseshoe dissepiments with stereome on row, * 7. P.R.I. 44793, transverse, illustrating stage of growth with large,irregular dissepiments, * 4. P.R.I. 44794, transverse, showing adult budding to give off two offspring, x 4. PR.L. 44795, transverse, specimen apparently belonging to P. websteri, but occurring in Nora Member of Shell Rock Formation, * 2. ie 9 142 BULLETIN 355 EXPLANATION OF PLATE 43 Figure Page I—6: /PachyphyllumiwoodmaniHall-and: Whitfield; 87/30) = acy ee ieee cece eee ieee) cee eet canes aa ae aan ae 1. PR.I. 44802, transverse, colony with long septa, ‘‘aulos’’, and heavy septal dilation, * 1. 2. PR.I. 44803, transverse, colony with short septa and open spaces at corallite axes, x 1. 3. PR.I. 44804, transverse, colony with small diameter corallites, * 1. 4. N.Y.S.M. 3580/1, neotype, transverse, * 2. 5. PR.I. 44805, transverse, colony strongly resembling neotype, * 2. 6. PR.I. 44806, transverse, colony with variable development of dissepiments, < 2. PLATE 43 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 ke Ss Sasa b were \ SD Lu i ‘te ‘ PLATE 44 BULLETINS OF AMERICAN PALEONTOLOGY, WOLUME 113 ete se wu DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 143 EXPLANATION OF PLATE 44 Figure Page Nas. (Ara yn ine (aa a? Weel sivel WTO, WEE! sos beocoeoee gene penbondodoebouébocopagcorgsucoDuGeoDoOONE 78 1. PR.I. 44807, transverse, colony with “typical” corallite size, * 2. 2, 3. U.S.N.M. 78629, holotype of P. levatum, a P. woodmani with moderately large corallites, 2. transverse, X 2; 3. longitudinal, x 2. 4. PR.I. 44808, transverse of colony with heavy septal dilation, x 2 5. PR.I. 44809, transverse of colony with very heavy septal dilation over horseshoe dissepiments, * 2. 144 Figure 1-5. Pachyphyllum woodmani Hall and Whitfield, 1873 Ren > n . PR.I. 44810, transverse, colony with long septa and very heavy septal dilation, x 2 BULLETIN 355 EXPLANATION OF PLATE 45 U.S.N.M. 78646, holotype of P. ordinatwm Webster, 1889, transverse, colony with heavy septal dilation and long septa, x 2 U.S.N.M. 78629a, P. levatum holotype, longitudinal to illustrate uniform horseshoe dissepiments, X 9. PR.I. 44811, longitudinal, enlarged view of single corallite illustrating long septa, rhipidacanthine trabeculae and horseshoe dissepiments, * 9. . PRI. 44812, longitudinal, single corallite with rhipidacanthine septal trabeculae arranged in fans over horseshoe dissepiments, and tabularium with axial and periaxial rows of tabulae, x 9. PLATE 45 1S BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME ee AACR: 9 URR PLATE 46 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 a + ae DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 145 EXPLANATION OF PLATE 46 Figure 1-6. Pachyphyllum woodmani Hall and Whitfield, 1873 1. PR.I. 44813, transverse, corallites with light skeleton, aphroid in part, with moderate septal dilation and long septa, x 2. PR.I. 44814, transverse, corallites with confluent, complete septa, moderate dilation, and long septa with aulos, * 5. 3. PR.I. 44815, transverse, corallites with heavy dilation over horseshoe dissepiments, X 5. 4. PR.I. 44816, transverse, corallites with heavy dilation and long septa, < 5. 5. U.S.N.M. 78629, P. levatum holotype, transverse, with very heavy septal dilation forming solid ring around tabularium, and with long septa forming aulos at axis, X S. . U.S.N.M. 78646, holotype of P. ordinatum, transverse, showing very heavy ring formed by dilated septa and heavy septa between corallites reflecting heavy, lumpy septal trabeculae, * 5. a 146 BULLETIN 355 EXPLANATION OF PLATE 47 Figure 1-5. Pachyphyllum woodmani Webster and Fenton, 1924 1, 2. U.S.N.M. 78615, holotype of P. irregulare, 1. transverse, illustrating large corallites, * 2; 2. longitudinal,enlarged to show steep-sided calicinal pit, * 4. i tr Ww . U.S.N.M. 78615, holotype, 4. longitudinal, horseshoe dissepiments, * 7. U.S.N.M. 78647, paratype of P. irregulare, transverse, * 2. 2; 5. longitudinal, enlarged to illustrate rows of differentiated tabulae and PLATE 47 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 ‘“ ME Sue BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 48 Figure DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 147 EXPLANATION OF PLATE 48 Seach y Diy LUMNCTASSICOSEALITI WV CDSLETAUS BON ey ce ln eee ose ot Soe ETO TE nee eee 80 1, . U.S.N.M. 78628A, lectotype, 1. transverse, with large corallites characterized by flat-sided septal dilation, x 2; 2. longitudinal with corallites containing abundant irregular tabulae, x 2. . U.S.N.M. 78627, holotype of P. owenense, transverse, to show that this is just a small diameter colony of P. crassiacostatum, X 2. . U.S.N.M. 78628, lectoparatype, transverse of characteristic specimen, * 2. . U.S.N.M. 78628A, lectotype, longitudinal, to illustrate abundant incomplete tabulae and numerous dissepiments internal to the row of horseshoe dissepiments, * 4. 148 BULLETIN 355 EXPLANATION OF PLATE 49 Figure l—Guerachy phylum crassicostatum Webster 1889). 1 -e ees: ater eee een in een nn iene enna 1. PR.I. 44817, transverse of specimen with typical septal dilation and with open area at axis, X 2 . PR.I. 44830, transverse of specimen with small diameter confluent corallites, * 2 x 3. U.S.N.M. 78628A, longitudinal of lectotype illustrating horseshoe dissepiments and fan-like configuration of coarse rhipidacanth trabeculae, x 9. 4. S.U.I. 3598, longitudinal of coarse, rhipidacanth septal trabeculae forming tooth-like extensions on margin of septum, X 9. 5. PR.I. 44818, longitudinal of corallite with no internal dissepiments and very long septa making an irregular axial structure, X 7. 6. PR.I. 44819, transverse of founder corallite of a colony, * 4. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 49 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE Die Signe apes ee a ne ane Ps ete ott ‘6 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 149 EXPLANATION OF PLATE 50 Figure Page [PRR ACHYT EV ITEICI US ICOSIQUITMONECDStCC MUGS Omen rs ia inert chia. Cleric h wen ae ten ee eee ea ee ee 80 1. U.S.N.M. 78627, paratype of P. owenense, longitudinal, showing stereome deposited on row of horseshoe dissepiments, * 4. AE IATA ATIAITED CINTA tb Soy a ob a foe Heb eee re Go 8 Do SOME Er EGOS poi ouomon Gooch Doped D oo boom an 82 2, 3, 4. PR.I. 44820, holotype, 1. transverse, < 2.5; 3. transverse, enlarged to show long septa and aulos, < 6; 4. longitudinal enlarged to show septal trabeculae and incomplete tabulae, 15. 5. PR.I. 44821, paratype, transverse, with very small corallites and clearly formed aulos, X 5. 150 BULLETIN 355 EXPLANATION OF PLATE 51 Figure Page 5 hachyphylumidurmont MeeSp rrr acre oane seis eee eR ee ee he ee ee ee ons 82 1. PR.I. 44822, paratype, transverse, to show various weight of skeleton at different growth stages of colony, x 5. 2. PR.I. 44823, transverse of colony that was aphroid at some stages of its growth history, * 5. 3, 4. PR.I. 44822, longitudinal; 3. illustrating horseshoe dissepiments that are irregularly developed, * 10; 4. corallite with regular n periaxial tabulae interrupted by long septa at axis, < 10. . U.S.N.M. 98282, holotype of P. nevadense, transverse, with development of dissepiments of near uniform size as show by intersections, X 5. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 51 5 i Rise Cay wre re 4 ae é . Ge ; patios Ty ao Le : GA SS ~ ta - Pek bs FRA eo 422mg, PLATE 52 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 4 ae ee oe DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 151 EXPLANATION OF PLATE 52 Figure Page l=), OTUs ED, Weg co Gonos eGboemo oe oS OCU OO Hon 5 Maemo UmoDIGGoo MnO HG on bo Doe Pero bond sons omeoes 84 1, 2, 3. PR.I. 44824, 1. transverse in colony with transverse and longitudinal cross sections of mature and juvenile corallites, x 4; 2. longitudinal to show variable development of outer dissepiments, including ladder-like forms (arrow), X 6; 3. lon- gitudinal with horseshoe dissepiments, * 7. WNL WW trreraan siti (sell al WAM IEW cooesoaunacenumonmopmpoo ooh ooo ume udp od Ocoee en aoosooouoouGoDOD 86 4. U.S.N.M. 135374, X 2. U.S.N.M. 135381, X 2. U.S.N.M. 78449c, x 1.9 U.S.N.M. 48449a, neotype of species, external, X 2. U.S.N.M. 32706b, X 1.9. nn egal (en 152 BULLETIN 355 EXPLANATION OF PLATE 53 Figure Page 1=235) Macgeeaisolitaria’ (Halland! Whitfield 18/73) aera snc rete tes oe aloha) ete) oh oie) ol =i chip eh estosic) Mey ePicy oo =p-r lean -riertslfo taller oie Ren tied eee Series to illustrate variation in topotype population. 1, 2, 3. U.S.N.M. 48449a, neotype, 1. transverse at calice, 4, 5. U.S.N.M. 135374, 4. longitudinal, < 2; transverse, * 2 6, 7. U.S.N.M. 135381, 6. longitudinal, < 2; transverse, X 2. 8, 9. U.S.N.M. 2273b, 8. transverse, X 2; longitudinal, x 2. 10, 11. U.S.N.M. 78449d, 10. transverse, X 2; longitudinal, < 2. 12, 13, 14, 15. U.S.N.M. 78449f, 12. transverse at calice, X 2; 13. transverse, X 2; 14. longitudinal, * 2; 15. juvenile, x 2. 16, 17, 18. U.S.N.M. 32706a, 16. transverse, X 2; 17. longitudinal, x 19, 20, 21. U.S.N.M. 32706b, 19. transverse, X 2; 20. longitudinal, x 22, 23. U.S.N.M. 32706d, 22. transverse, X 2; 23. longitudinal, x 2; 2. transverse lower in corallite, X 2; 3. longitudinal, * 2. ; juvenile, X 2. ; juvenile, X 2. NNN PLATE 53 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 54 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 153 EXPLANATION OF PLATE 54 Figure Page NO IOGear Sana (GEM aical \WWiINnelel IEW) ssob coo saousebepeeoooueeoeUDUUUooudcocHUaGOooUROOE HOODS oROeoE 86 1, 2, 3. U.S.N.M. 53181, 1. transverse, X 2; 2. transverse in youthful part of corallite, x 2; 3. longitudinal, x 2. 4, 5. PR.I. 44825, 4. transverse, X 2; 5. longitudinal, X 2. oO . U.S.N.M. 78449a, neotype, transverse, illustrating typical septal dilation, x 14. . U.S.N.M. 135374, transverse, axial part of septa almost forming aulos, x 8. U.S.N.M. 2273b, longitudinal, showing horseshoe row of dissepiments and irregular single row of external dissepiments, * 12. Outermost are encrusting auloporid corals (arrow). . U.S.N.M. 78449d, longitudinal, enlarged to show lateral expansion of outer dissepimentarium and numerous dissepiments developed as corallite expanded over soft substrate, * 12. 154 BULLETIN 355 EXPLANATION OF PLATE 55 Figure Ss Maceeealsolitarial(Halleandawihithelds 1873) emus iei eee iene Eee Renna ae an ncn ae eee Ec Series to illustrate variation in longitudinal section. 1, 2. U.S.N.M. 2273a, 1. multiplicity of external dissepiments in more adult part of corallite, x 7; 2. enlargement to illustrate lateral expansion on soft substrate, * 12. 3. U.S.N.M. 20722A, corallite with long septa, interrupted tabulae, and few irregular external dissepiments, * 5. 4. U.S.N.M. 53181, individual with several rows of internal dissepiments, sparse and irregular external dissepiments, * 5. 5. U.S.N.M. 7798A, corallite with sparse, flattish external dissepiments and heavy stereome coating on horseshoe dissepiments as well as heavy, stereome-coated tabulae at several levels, < 5. PLATE 55 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 56 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 155 EXPLANATION OF PLATE 56 Figure Page NWT CYA MOTO AT TTT Es ETERS CBR Ors Chas cS 3 eee eee ee PCs SSS cm eS Git MACS O.od,.6 0 Lotions ano 6 Sea ae 89 - S.U.I. 3490, holotype, 1. transverse, * 2; 2. longitudinal, * 2. . PR.I. 44826, paratype, 3. transverse, X 2; 4. longitudinal, x PR.I. 44827, paratype, 5. longitudinal, < 2; 6. transverse, X . PR.I. 44828, paratype, 7. transverse of long-septaed corallite, * 2; 8. longitudinal, x 2. . PR.I. 44826, paratype, longitudinal, enlarged, with heavy stereome coating on horseshoe dissepiments and numerous internal dissepiments, < 10. 10. P.R.I. 44827, paratype, enlargement of septal structue typified by fans of rhipidacanthine septal trabeculae, * 12. 11. P.R.I. 44826, paratype, transverse of coral with short septa and shorter cardinal septum, * 10. 12. PR.I. 44829, transverse of long-septaed corallite with irregular ends of septa forming a loose axial structure, * 10. x x woe tN N ool Se Cant n 156 BULLETIN 355 EXPLANATION OF PLATE 57 Figure Wee Maceceaiconcinnitla ns Sp rae eee eee eer eee Ran ana ee nee keene , 2. §.U.I. 1257, holotype, 1. transverse, X 2; 2. longitudinal, x 2 4. S.U.I. 1252, paratype, 3. longitudinal, < 2; 4. transverse, * 2. 5, 6. S.U.I. 1256, paratype, 5. transverse, X 2; 6. longitudinal, x 2. 7, 8. S.U.I. 1258, paratype, 7. longitudinal, x 2; 8. enlarged to illustrate tight fans of septal trabeculae and variable development of “normal” external dissepiments, X 8. 9. S.U.1. 1252, paratype, longitudinal of coral with heavy, tight fan of septal trabeculae over horseshoe dissepiments, numerous internal dissepiments, and sparse, flattish external dissepiments, x 9. 10. S.U.I. 1257, holotype, transverse, enlarged to show heavy coat of stereome on horseshow dissepiments to form a solid ring around the tabularium, * 10. 11. S.UI. 1258a, paratype, enlarged longitudinal, with clustering of several rows of internal dissepiments with horseshoe dis- sepiments under tight fan of septal trabeculae, * 12. BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 113 PLATE 57 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF ISS7/ INDEX Note: Page numbers for descriptions of genera and species are shown in bold type. J NRT FACE co a 8.5 3 ar ana Sad co AC ICES BHD COORD OCP SOC ODNCOCeICoS BA CELUI IC ZOD wees ciiciccieeicicteeniatet Actinostroma, “Actinostroma zone” ... RAVE NE SUE Racine cee ramos Soke onesie isin aiciniainteralsisistc ciis(cleis wieistelacielarsys amplexoid septa ........ 33,36,39,40,42,43,44,47,49,55,56,115,119 APHLOIG wee eeeseceelslnasiel as 28,30,31,75,76,77,78,82,138,141,145,150 INT META OY UTE C Soacnacco conbsarodaccdenuanbougcosapbsscoueseaceouoRn 34 IN BANU T Ae) op ocenccenaccsor lec onacooer pose EesCCODOEIOS00V0000000 eee (04 ETULIS se mcoaaneaceciscaseee 78,83,142,145,149,153 axial boss 34,39,42,43 axial and peri-axial tabulae ... 28,31,63,64,66,68,129,130,133,144 isi, CURE saconsancosascasosenosdqaceopoqaqdpbecsnoucanoogaE 8,12,27 PIE QUTTEIAY as canooanpepnonougnorespasespsooSoesoces 34,41,42,44 BL AOSTA” sanicinasscnadn aaa aassoseaccapogongongesasunbacnonas9Deac 71 VCE ee) NY Soa ses sassoncbensecopesceoussosesbosoosoEHpaoooopaDocCAS 21 Cyrtospirifer whitneyi Zone .......-...-..++..s+e0seeeeeeeeeee. 22,23 [DYNA IT) eee TBONE Sagsnqcanasaaenges65de09000095500 00990055 23 Pinte CONISUCLAPZ ONGiesen sae ase cee ces ae aelcieisierst ie eieisin eel 23 Towatrypa OWenensis ZONE ...........001.. ce. eeneeeceeeeee eens 22,23 (LT GTA RTE) TAO. se poagascngd sun agdonpqnoonscocpaonscesoccestec 22 Nervostrophia thomasi Zone ..............+.0000ceeeeceeeeeeeeees 23 Strophodonta cicatricosa ZONE ......... 2.6000. e0ee cece e eee 21,22 Tenticospirifer shellrockensis ZONE .........0.06-00 ee eevee ee ZR22 By ie! (ERIN o.scoccanconomacopdeagssoccaobacacvovaspouapbcuspSoua0e 17,23,26 ent RIE” REBEL socosngcasagnoveunosuns 54,57,59,60,64,66,67,131,133 (Craakie WANE) Giro) cooscnscoonoscadbesosaogconopsocoppoDoconHGoSqC O22 Eeithopraph! City HOrmmAawOm cere erate oiaie's ofeeiateielsitnter= elm cleo =i= 9,22 (CHERIGIS A NINIGRS ce sacneaudocberoascanconanoscndocgeqununcabbgnnne Sis}5i7/ (UGTA CTS TIATO pacticecechobenonss coonot ese senouuouHeeBoONOSOOC 8,53,57 (OLIDAT VND scoeasconcusacnarecscaceceseroras §3,54-57,101,123,124,125 iia w aisln ainvolale 63 IO VA PO a To ee aeRO DEE CURE EE BOO” DOODUCUD ETE CUO Ode -onLapgnoucc 59 peripheral dissepiments in ...........----- 58,59,60,61,62, 127,128 Septal dilation inl s-ccsssm-occrecceereeniseeeesereresseeesese 58,60,61 Septaliitra bec acme stetetnelde tetesteeierceitestiesiisisacte 58,60,62,63,126 Diversophyllumescncesseseces ose. vaaeeesaace sae seeeesee eee ee 34 IDYO RTD). conoprgacknodacoDacseocopAcnecdnade See Lae. DuUumMontlowa Goaseeeccmveciecestidssestmncnce-csescenccaeeeee cece 19 CAPENZONE Filo nets cemacciasacesitamaaieasinsticleciels/asicsetmeemesenestterte 85,87 Endophyllidae sss. c-r ccceecise cteisecsenerecr ese eberseece eerie QTR 51 GSH CORAMNIOS: osdonccoonadosacuoonoopaccooGudosnDdacoasdacsnocsdas 78,80 BAMENNIANG cece coc cessek ceeiseite sect nacre cea ee Ceeee cane 23,34 Fenton;:@- and Fentony Mi) csccccesnceesecsese 8,15,19,25,29,33,38 Biloy diaibedsp acne asaseee saeco eeecemace cere rose eneree 17,19,20 JAI NEN Gonna caddhbopedanndddacnaosnbacsnaessacdacosopnstoqoconcns 7,8,22 INARA MN CLs} b .Seepoccebopsaodoonon oo ConuoObuaADOGSRSeaNeESboRoSDOGS 12513) Caibreoytal Leo. MIB eel Gomes odenec conasocdossousoonoscoenoossoS 16,17 (GRAGATAEHI canssgocesnsansccanndedoorbesos=ssesossoususcossoass000005 17 Greene wMlOWa wea seeeee se cece eee are eee hee e Eee cee emer 15S growth (seasonal?) banding ................. 29,34,60,77,83,105,138 REVS SAY SLETES souccpoqconcopooodondoagonapadoDnsatingosedoscadsoaE 8,14 Hallferand) Wihitheld Rep ccrescscre cece 8,25,28,38 IEGNIGIPAGA naciciaanacuosboodoacebe osodeouoensscboDosboNssadeucsooNOR S)7/ Heliophyllum 54,56,59,64,65 Hexagonaria 16,63-64 “carination”’ of septa Acervularia whitfieldi b LEROIAT soococoncoctoondedes . bassleri depressa Dbassleriumagridmerectccccrr cece ee sescer ee TET AAT NS). coescasobooocooescoonasusebonnbsrocodcsoeSsppasdcooa5as JOBINTO GT! «oc gqconnpacchusdcoosudsouSuseBasbUR0R0 HATES oceSooocbaocas0spcoacousdeganeoe 68-70,101,133,134,135 (AIC Vian donenbodonaaenpponbsopbooseUnapnadse 64,67-68, 100,132,133 . marmini RETTTDTALTAS . reticulata Septalidilationmniere reece ntti li-t 63,64,65,69, 132,133,135 Septal) trabeculae ims see cm vnc ir stelereein)-te-t= 63,64,65,68,69, 130,135 tabulae, axial and periaxial rows Of ...........-..+25+ 63,64,65,68 [SAND Gosdsonandcacobbcnnnconsnconospcadconnacas. Aka shh See 70) horseshoe dissepiments .._ 70,71,72,74,75,77,81,83,85,87,88,89, 90,91,136,137,138,139,140,141,143, 144,146,149, 153,155,156 Idiostroma beds (Amphipora) ......0....2.0ceeeeeeeneee een eeneces 17,18 LO Wap iy lL arr erelac)erctel-ijateislete ole sale ele ole ee ete eRe 8,16,27,28-31,70 I. johanni ......2.0.020000e020+++- 24,28,30, 31-33,101, 103,104,105 Ib, THAR TED) canna scadeé oncoubacsooodvoob scooPenade 9052 24,30,31,32 ETTORE ccecongageannoansencpesossonse 24,30,31,32 IL SKA choad nascAenobooscoSboooUobeancoanonoqceaaDaecc S05 SKS aphroid coralla in 28,30,31 axial and peri-axial tabulae im ...............------++---00+0. 28,31 INteELCOKal Lite mew all Sewn settee ieee eer eee 28,30,31,32 septal crusts and ridges in ........... 28,29,30,31,32,103,104,105 Keyphophyllidaertrscemsee cere e ateet esis electorate setae 33,49,51 158 BULLETIN 355 TEDLOSIFOPRIA GARAGE: nen see veioeotenin sce eteacsisacisceciesis ee eee ecerr 17 eimexGreek Foumationlweaereekeereseeesceeceneee see 7,8,14,21,22,24 Cerro; GordoyMembersececreescceeeee ser eee eee eceee 14,15,21,24 JuniperdculliMemberseaser crete creck cececcme tac 14,22,23,24 @went Member pe-stccceecsscive ssc cse set seriianae ance 17,18,20,23,24 lonsdaleoid dissepimentarium ................ 33,35,36,37,44,46,118 MAGCSCCA Mele do geen naa iuleunis ade boaa bios neeeee oe 8,72,85-86 Wb XAT NGGINDE GhapanoAcaseppcaocoUndcooncdgeooaddobasnoscaceosuauce™ 88 WE CCERBHIA CHAE. copacencsanacanqnbbooadepoaaaKoNRAoDDOr 88,89-90, 155 MESS CAINOGRID: we races sete tala saigioie oie erm a's. visleloisisiejs ss sioreislersteteeiee acces 91 Wh COG ATLL cancopedouvoodocbsencuonpsseusoassussopesdase 90-91,156 WE CIDE reoctancdadancastposoobon0 ou DaUS En Sa seco O pe usBU oeSnba 88 WVAEES CLLIGA toreierafatate aisle ators me oysinvsiee tok cents sow snc ameceeeesseaoe 86,88,90 IMT AHiGl so snonnasonooonodongnnosboooouoscosuegEoonodcoeete 88,90 MSS Olt arias coneacceceeneereeseenc es cerer 86-89,90,151,152,153,154 MES (MGC CCG)! ieicreieccralcteyate slatesslshetoisievs(ereqars ota\s eyare/ai=(cvarsiafecaislevsisisssisiareiesaiciossis 86 WES Ginamnophy lium) aessceceecasecce ene eeeceece cee ceeee cee 86 CA SeEZONe MIN ere ceacceaecmeccence tence setter eaceeeccee cee 85,87 horseshoe dissepiments in ....... 85,87,88,89,90,91,153,155,156 NOMEN ODIILUNDemcctcesceecinscceaeecceeeseececten cece ce seenecseeeen 86 HPLC TOT TAIZAS se x creators siorso.0)5\5 1518 sfois a's 0\5\5/o)s (01070 <1d1s-0/cicjs aimretateiascioneeeoene 85,86 rhipidacanth septal trabeculae in ................. 85,87,88,91,156 5a} ell GU ETH) ites SaconnesdenppBeoabapaAsonpaacsaeseonD 87,89,90,153 frabeculanitanspnuen-seee cece sccereencneceaen eee en eens 85,87,91,156 tripartite dissepimentarium in ..................05 87,88,89,90, 154 Marble Rock, Iowa 9,10,14,16 NVI ATES ASTIN re crore orate soins 91 ais siaisjs s slots sistee s Sole se eles sGelereie oles else ee emacs Mason City, Iowa .. Medusaephiyllunits.ne- scacenccen cals nes cneteecn elses monacanth trabeculae, coarse ...... 54,55,58,60,62,63,64,65,68, SeOnede eran SesneNcacach CE Teac ae canonecnemere ier 69,126,130,135 monacanth trabeculae, fine ........... 34,40,41,43,45,47,48,108, miciejciererese oliaacraysicle es etaerhe e oaaielatedariet se eaeiniee deilesaies 111,114,117,118 Montagne Noire conodont zones WM OUTLONIGI DES prereener nna telasnti Soleil asweiacsemeacerc roach is INGEST AC Mosonadaspnneosndcuoaannoonessccmbodvoacrecsaoasbencand: 16 INOLaES PULLS, LOW aleaacsacretriscte eee enieee cries 11,12,13,14,18,19 OWeni Grove low aria sepsis csfernesitisteleeieiiepiniesiacbrnesee tine 15,16,22,26 JHA OTT ecenpedoocsdodburoneceseecduacuoussbeaescobe 8,16,19,70-73 PeR AMT AGIUIN ace nano rasee ra ence nase es ease recor ERO CEES GE Roe 82 oe DOUCNAI bers. asceaejancion sence de eeeineeetige cat accerete aieet 70,71 PE ECHENOQUENSISE c Sec cas eae ae sniecise Nelsen ete mercer ee Giseeonene ex 71 BA CONAUCNIS Mecca seater fen cenaccnice cepnere ences eee erie 75 P. crassicostatum ............_ 21,72,73,80-82,90,101,147,148,149 P. crassicostatum nanum FE CLS MDI GMa ste sclera ip sicteisaiaass site nee eiorsieineieincte entree Ceeaceereere AU ON Lantana aiecits ss snincacinen odooncecchaneeone Pam XE SU Camere soemecitsisiaiiecacenseiasinessccincsere QT ER AIUD trccntesie sscfecionene tactics ccailesacesite IP RIDEV LENSE recast na see nosinweroen vicina sen nance eee na eee 1 UPB FHIAR Es, Sa0cCOb GS ROOCUREOTE DOC CDRE CaaEOTA Con ERAR Aaa PMC VALU rrctatsic ate stetstetsisre s 62 5.2/slore eels steieeniaeisieenise soaleion eas ecoemieeaes IPAPILNULISSUMILT area near sseriiles jeer sidendsecacnenecs 73-75 ,136,137 Fe MITLLT LSETIS USM eect nnss sietrelsts ae sala selcieeivesenece te roche caece ete ee 81 12h, OTT ATORGS pnb Cone OUR TUCOS CUO OTE LOO CT ICRA COARSE Ea tae acr 74 POLLAN es arn nner olets elacionig oie naise teases teulecceene eee 79 PS OWENENSE Hae aa ceiee oreine astse ge Hiei aece cle tarenceccmee die sstes 81,82 TP AVATTADILE an eee eer ace ree eat ones si ce hea ene eee 75 I BRUNE OCA 7 earths CRSA HOSCC TO ATICERDCC ROSE AC orp caananneace 76-78,140,141 P. woodmani ......... 72,73,78-80,101,102,142,143,144,145,146 BR WOCAMANT AVOCAENSIS i osseniscnilecdcnecises sa csleeseciecenceieaane 82 aphroiceseptar inh wry -teereretelsrcterlet 75,76,77,78,82,138,141,145,150 acl (olSavs fel on is deqoBabcoduansococdaaodssooduoassonde 78,83,142,145,149 excert corallites in ......... 78,80 founder coralliteyimpececeseeeedstreeeeecescaeeccars ... 78,80 growthibandin gain encccacsesccsccecasanceniesteeceince cece 82,138 horseshoe dissepiments in .... 70,71,72,74,75,77,81,83,136,137, vopelcessiclelojtes cis eiietorelste eer 138,139,140, 141,143,144,146,147,149 rhipidacanth trabeculae in ................ 72,74,80,81,83,144,148 septalliconfluencysinis..---meeeee setae eee 75,76,78,81,83,137,145 septal dilation in ........ 70,73,75,76,77,78,79,81,83, 136,137, ofan ctc ciarstelan taislesta ae crslote sts ertcitere moet sic Glersseee 139,143,144,145 Septalbtrabeculaeginte-ceeraceereeeeeeeeeeeeec 70,74,75,77,81,137 trabeculansiams)inlisertresceesecae/atareietsiectcteeieteh ieee eet 71,74,137 Rarasmithiphyllurm vrsccc rece os eeosconceeeaaeece ence reesreeeeree Sl PenecKiellad ork.ragncetsseesaccine ces asach emaceee maseeeemasac settee 58,62 peripheral sag of tabulae ..... 33,35,36,37,38,39,40,42,43, 110,112 Pexiphy lume hvcsantisccseencaaccun ae cs ctasaetacneaettenecteere- tees 86 Bhillipsas trea. tn acecesijass cese ae ee eetertes cee see eect 70,71,72,73 I cow (400101 lapaeeperadecteconcecbcrtadcceacprtorccnbaccdopccdoopcoccancac 73 Phillipsastreldae yo nis.ntsosse sos eeee ce ostsiaseumilaeeeete 57,64,70 Portland) Tow.al as .-tleyetosiete/atnissereielasseceiassteciaeeeeeometrireeeecet 16 presepiments -........ 33,34,35,36,37,38,40,41,42,44,46,47,105, asajarotayaratt el anata siciatelatstatectatereteis Sine eaiciele ee oe tate ae 106,119,121,122 IPSCUdONREXAGRONATIA -Jasaccserenntecate aan eee eee 64 PLCrOrrhiza:..cesseinies sa isaac jars devecusateataasedasee dade eteee 85,86 rhipidacanth trabeculae -. 72,74,80,81,85,87,88,91,144,148 Rockford lowaleee-crerdae. cena 9,11,13,14,15,17,20,26, RockwellSlowal a .ccsescsen cee aaeeraeer ere rerner 19,21,23,26,27 Roseville; Towal 2. .cceeec. ss 15 Rozkowskaella ................ 86 Rudd Towa) -a.siccsactetspas assis sserciciciciare cusictelivaystsisietavevalaje ovotajoreine oieloleters shes 20 septall(crustsyand ridgestanes-.00--csescee 28,29,30,31,32,103,104,105 septal trabeculae ....... 49,52,56,57,58,60,62,63,70,74,75,77,81, Eratatsrale area netere etoie a aisle steerer CNS eT ereeevoeee 111,117,114,126,130 septal dilation .......... 38,40,42,46,58,60,61,63,70,73,.75,76,77, ee dose et sae ele eee 78,79,81,83,132,135,136,139,144,145,153 Septothecal Bansscecnecnceieacece 34,37,40,41,45,48,49,50,52,115,118 ShellGRocksBormationige naaseecie lctecinsctssertecnee 7,8,9,21,22 MasoniiGity Member ta.ncssq-nissa-liste ceases 9,16,21,22 INorasMember aepcren cseetreiissrcsseincisesnereeittrer 11,12,21,22 Rock Grove: Membetirernccccccssescecsceececeececneamesceeeca 10,11 ShellUMRocksRiverse..-mserisse ceca cece ecaeceea 9,12,13,16,18,19 Sinospongophy lum ere cas. scessceblccsccsaceemtscee see ceeeaeretice 34 NIAC 112) mein adisces OU DOA SEEORO OOD NAA AEtcD CAaS Dn acm On Rabu EOD DOaDeL NUNS 32 Sa INUltiNAdlAta ws. tesjtescawe wuss sjaidaiasinwacis onions os aes REESE EE EMG OL SIMI ICVAINUS. o.sieeisae -sdosee soo secs ise eeesaceedoaace dee cceeee ss 84,85 ISIULA LD RY LULAIIE caeletolelerowlieielottsteeieris tei -tecctereeiatete eseiaein eee 8,33,49-50 Se belanskit’ sjcceys-eeeoat eos cece reece ee 49,51-53,121,122 PLESEPIMEN (SHIM eet ese eels eee cr rere $1,52,121,122 Septal trabectilae nine cmrraesst-etssisptset ceases eeeeeiretts 52,121 septotheca in 2 “Spirifer zone” 2 Spongophyllum Stratigraphic Distribution, Rugose corals SEL Le) 7X0) VO” sanancppbondnbancoarsnabsaAbaagcesdaauaonooed SE OMNDOGES iegasacccdsoeccweseteecaencenecserectiesieccesoteeerriis S532 RE lela a Cob eononssoansncoannaacosdeadaoosaSoccaboasopoocaudosnd000 29 SPMAPSINAIUSH en cetse aston aaa eaeeee eae Cee eeeeeee 30,31,32,33 SAN Of tlie. scelcsnaeiasssceccceeen seme ccbaecccesecc eaten es 29 ISEOPNHONELOIMES mae meter-tnranietstctersloletetarctaveiniatetera rn orereeraa sicel ee eeerersererereter= 17 SUT 22 Goa sopodcooscmusadobuasnoracnoaansdacnnnsacsonoanccassansans9 28 Sulcorphyllum: Wa.naseensssescecescececeacoeatiecs eee er eerie 84 YStematic Paleontology ceri csaietelaicretersteretalsreraterstelstelerereelsri tye tartetslsyorateters 24 DEVONIAN RUGOSE CORALS OF IOWA: SORAUF 159 TANT OUIATO. gondoqucorsnodnssdneessueonsnsadssomonpoasa 8,10,19,33-34 TRACT LY Oo ySepeSnEne Con OUS ORC CORDED etn ICaSOSC HRC Reon Aee 47-48,118 TREGUILENL EP RE cases se getciercistetnt scale cians oral ctelaraisrete 45-46,49, 100,116,117 Tala. Gdaccincnp Joo obaCGOOT MONO CHa OREM ARE SUDCEE ene Ho OSOTaCae 46 Th CAGES? cangpnecnncerouosscdbaccodaaareTonomoddo on 35-36,37, 100,106 He CUGQTQAR. coanseoacdosor bons opsaspontocnosansno0assons 36,37-38, 108 WR ELECIIGIIN cree eastern anes sees e Oaiee amin seenie oniseicejeice tales 35 FL, CRTOTP. conmcandoagobaccoarassos psabapns coor sosobooocossUooousS 39 Te. GENAISIGC ohenneacoooaceseedsc conghOnSossonBUESoORdooe 43-44,46,114 Ue OMS TY aagdanbbooroactoRdacceheduognsccoducsapbeDconsesonaDaDOObOG 34 AMLEVOTS OM Mrertoce Senta oeceie tacieierece cictaralseisisiateins 46-47,117,118 The [ERMA sasosaobopacoaspobonandonoahaonseospoecoooconsoscasos 45 Tis HAV AIHO msasoosbeoosceuRsseeossbnenosonsnsnen 34,39-41,110,111,112 TAINGEONNEL Las asta s acs won Rese ososeseseenen dace see seek ms 38,39,45 Ths ATED. eopechecasectneEnecnonceeneennnTaae 41-43,46,112,113,114 RTD. Gasccesoascoocedoapssanoe scape soopecgacopsyosunondns 37 TR ITLELY LCM eae cate ictetel sete et sas clelntclereelore(o siclel ells -folote)siayesatelsforsieleisissrale 34 TER IUL ADIL OM acerca Sosetasleistetecn-nicteisicietoinie sisieis 44-45,100,115,116 UETOVINIITINY ctoeaissistalstaisin/