JANUARY 30, 1985 THE NAUTILUS ISSN 0028-1344 Vol. 99 No. 1 A quarterly devoted to malacology and the interests of conchologists Founded 1889 by Henry A. Pilsbry. Continued by H. Burrington Baker. Editor-in-Chief: R. Tucker Abbott EDITORIAL COMMITTEE CONSULTING EDITORS Dr. William K. Emerson Department of Living Invertebrates The American Museum of Natural History New York, NY 10024 Dr. M. G. Harasewych 363 Crescendo Way Silver Spring, MD 20901 Dr. Aurele La Rocque Department of Geology The Ohio State University Columbus, OH 43210 Dr. James H. McLean Los Angeles County Museum of Natural History 900 Exposition Boulevard Los Angeles, CA 90007 Dr. Arthur S. Merrill c/o Department of Mollusks Museum of Comparative Zoology Cambridge, MA 02138 Dr. Donald R. Moore Division of Marine Geology School of Marine and Atmospheric Science 10 Rickenbacker Causeway Miami, FL 33149 Dr. Joseph Rosewater Division of Mollusks U.S. National Museum Washington, D.C. 20560 Dr. G. Alan Solem Department of Invertebrates Field Museum of Natural History Chicago, IL 60605 Dr. David H. Stansbery Museum of Zoology The Ohio State University Columbus, OH 43210 Dr. Ruth D. Turner Department of Mollusks Museum of Comparative Zoology Cambridge, MA 02138 Dr. Gilbert L. Voss Division of Biology School of Marine and Atmospheric Science 10 Rickenbacker Causeway Miami, FL 33149 EDITOR-IN-CHIEF Dr. R. Tucker Abbott American Malacologists, Inc. Box 2255, Melbourne, FL 32902-2255 Mrs. Cecelia W. Abbott Business and Subscription Manager P.O. Box 2255 Melbourne, FL 32902-2255 Second Class Postage paid at Melbourne, Florida and other post offices The Nautilus (USPS 374-980) ISSN 0028-1344 A quarterly magazine devoted to malacology. Copyright c1985 by American Malacologists, Inc. OFFICE OF PUBLICATION American Malacologists, Inc. (United Parcel Address: 2208 South Colonial Drive, Melbourne, FL 32901) Mail: Box 2255, Melbourne, FL 32902-2255 POSTMASTER: Send address changes to above. Subscription Price: $15.00 (see inside back cover) $17.00 (foreign); institutions $20.00 THE NAUTILUS Volume 99, number 1 — January 30, 1985 ISSN 0028-1344 CONTENTS Richard H. Bailey Human Modification of Molluscan Habitats in Little Creek Estuary, Virginia. Mark E. Gordon Mollusca of Frog Bayou, Arkansas Anthony D'Attilio and Barbara W. Myers A New Species of Pygmaepterys Vokes from the Western Pacific (Gastropoda: Muricidae) 9 William K. Emerson Murex hamatus Hinds, 1844, a Living West American Species Assigned to the Neogene Paciphile Genus, Pterorytis Conrad (Gastropoda: Muricidae) 14 Clement L. Counts, III Corbicula Jluminea (Bivalvia: Corbiculidae) in the State of Washington in 1937, and in Utah in 1978 18 Raymond W. Neck Tropical Veronicellid, Laevicaulis alte (Ferussac), Established in Southern Texas 19 L. A. J. Al-Hassan and Z. I. Al-Hasani New Records of Marine Mollusca from Khor Abdullah, Iraq 20 Paul E. Fell and John H. Williams Distribution of the Snail, Melampus bidentatus. and the Mussel, Geukensia demissa, Along the Pataguanset Estuary (Connecticut) in Relation to Salinity and Other Tidal Marsh Invertebrates 21 William K. Emerson Two New Species of Lyria from the Western Atlantic (Gastropoda: Volutidae) 28 News ii Meeting ii NEWS For more information about the Clearinghouse, please fill out and mail back the coupon below. HI Position Still Open The Department of Invertebrate Zoology, National Museum of Natural History, seeks can- didates for Zoologist GS-11/12/13 (starting at $36,327 to $25,489 per annum), to perform cura- torial functions and collections-oriented re- search in Systematic and Evolutionary Mala- cology. 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D I am interested in sending my order by mail. □ Please send me your current catalog and user instructions for the systemls) I checked above. Name_ Title_ Institution; Company. Department- Address City Phone ( _State_ -Zip- Mail to: University Microfilms International 300 North Zeeb Road. Box 91 Ann Arbor. MI 48106 1985 AMU Meeting The American Malacological Union will hold its annual meeting on the campus of the Univer- sity of Rhode Island on July 29- August 3, 1985. Three symposia will be presented: one on mol- luscan egg capsules, organized by Jan Pechenik; a second on molluscan radulae, organized by Robert Bullock and Carole Hickman; and a third on ecology of freshwater molluscs, organized by Eileen Jokinen. There will also be contributed papers, a poster session, marine and freshwater field trips, workshops, an auction, exhibits and commercial sales of items of interest, and a New England clam bake. A program to honor junior malacologists will open the meeting. The Boston Malacological Club is planning special events in commemoration of its 75th anniversary. For further information please contact Dr. M. R. Carriker, College of Marine Studies, University of Delaware, Lewes, DE 19958. ii Vol. 99(1) January 30, 1985 THE NAUTILUS HUMAN MODIFICATION OF MOLLUSCAN HABITATS IN LITTLE CREEK ESTUARY, VIRGINIA Richard H. Bailey Department of Earth Sciences Northeastern University Boston, Massachusetts 02115 ABSTRACT Mollusks of Little Creek estuary in southeastern Virginia may be grouped into five assemblages indicative of the following benthic habitats: 1) fringe and em- bayed Spartina marsh, 2) solid substrata (rock, pilings, shell), 3) intertidal muddy sand, 4) subtidal muddy sand, and 5) black organic mud. Human activities in the estuary such as dredging, stabilizing shorelines, land- filling, disposing of dredged spoil, and introducing foreign solid substrata have modified habitats and/or sediment character thus altering the distribution of molluscan assemblages. Human activities within and around shallow estuaries of the southeastern U.S. may have substantial effects on the distribution and com- position of bottom sediments. Substratum type exerts a strong control on benthic molluscan assemblages (Bird, 1970; Johnson, 1972). This paper correlates particular human activities with resultant changes in substratum and mol- luscan assemblage distribution in the western segment of Little Creek estuary. Little Creek is typical of the numerous small estuarine systems in heavily urbanized areas of southeastern Virginia (Fig. 1). It is somewhat unusual in that it was formerly a freshwater lake (Pretty Lake) impounded behind the ocean FIG. 1. Map of mouth of Chesapeake Bay showing location of Little Creek estuary and area enlarged in Figure 2. view barrier-bar and dune complex. When the bar and dunes were breached by dredging, Pretty Lake became a broad shallow estuary. East of the bridge where U.S. route 60 crosses Little Creek, commercial development, mainly marinas, and the U.S. Naval Amphibious Base dominate the shoreline. West of the U.S. 60 bridge the original basin configuration has been less modified and the shoreline largely devoted to residential development. The western branch of Little Creek has about 21 km of shoreline of which about 26 percent (5.3 km) is narrow muddy beach, 51 percent (10.9 km) is fringe marsh, 18 percent (3.7 km) is embayed marsh, and 5 percent (1.0 km) is permanently stabilized by bulkheads and rip-rap (Owen and others, 1976). The preceding figures include a small amount of shoreline east of the bridge. Water depths over most of the western segment of Lit- tle Creek range from 0.5 to 1.5 m (MLW). Max- imum depths of 1.7 to 2.5 m (MLW) were meas- ured in channels under the bridge and to the north of the sand shoal near the bridge (Fig. 2). The tidal range is approximately 0.8 m. Surface salinities measured in August 1976 and 1977 ranged from 21 to 24°/0o with the lower values in the marsh channels at the western extremity and highest values in the vicinity of the bridge. Salinities at the mouth of the estuary near the Little Creek jetties in Chesapeake Bay ranged from 22 to 24°/00. Current velocities are greatest at the constriction produced by the bridge. No current measurements were made, but large ac- THE NAUTILUS January 30, 1985 Vol. 99(1) FIG. 2. Subenvironments and sediment distribution in western branch of Little Creek. Numbers give locations of mollusk and sediment samples. Inter tidal Muddy Sand B. Subtidal Muddy Sand 12 SAND E *° E" E2 E E,. ° d o E L. > CLAY GRAIN SIZE KH ; 3. Summary of sediment grain size analyses. Sand. silt. cla\ proportions of samples. A. Grain size distribution of sediments in subenvironments, B. Vol. 99(1) January 30, 1985 THE NAUTILUS tive ripples (2-4 cm high) and observable sand transport on the surface of the shoal (Fig. 2) in- dicate moderate tidal currents. Muddy and silty sediments are indicative low current velocities in most other areas. Sediment Distribution Sediment samples were obtained at 29 sta- tions (Fig. 2) and sediment types were mapped in the field at numerous locations along a longi- tudinal traverse from the bridge to station 10. The pattern of sediment distribution and sedi- ment character is summarized in Figures 2 and 3. Coarsest sediment is found on the surface of the sand shoal (Fig. 2). Intertidal and subtidal muddy sands occur along the edges of the basin, as small bars, in channels, and in other areas where tidal currents are strong enough to pre- vent the accumulation of significant quantities of silt and clay. Black organic muds occur in marsh channels, dredged cuts off the main estuary, and in the central portion of the basin (Fig. 2). The black muds contain very large quantities of particulate organic detritus com- posed primarily ofSpartina alternijlora and ex- trabasinal macrodetritus such as leaf litter. The extensive area of embayed marsh at the far western end of Little Creek baffles currents during flood tides and traps considerable quan- tities of mud. Mollusk Distribution Mollusks were collected with a 10 cm diameter pipe dredge or with a shovel in localities where water depth was less than 1 m. Samples were washed in the field on a 1 mm sieve. All mollusks retained were identified and counted. Species distribution for samples and relative abundance is given in Fig. 4. Due to lack of uniform sample volumes precise quantitative comparisons can- not be made among stations. All species listed were found living, but at many locations most specimens collected were dead individuals. Species characteristic of major subenviron- ments are listed in Fig. 4. Note that some species, such as Ilyanassa obsoleta, achieve greatest abundance on intertidal and shallow subtidal muddy sand, but are common in other areas as well. The intertidal muddy sand, sub- tidal muddy sand, black organic mud sequence of subenvironments represents a substratum gradient from basin edge to basin center so it is not surprising to see strongly intergradational molluscan assemblages paralleling the gradient. Da vies (1972) described a suite of molluscan assemblages from the Rappahannock River estuary that are very similar to those given in Fig. 4. Substratum type is only one of several important controlling factors. Predation also exerts a strong influence on the distribution of mollusks. Many estuarine species escape intense predation by living high in the intertidal zone (Geukensia, Littorina, Crassostrea), burrowing deeply into sandy substrata (Mya, Tagelus) or in- habiting soupy muds that are difficult for preda- tors to search (Macoma, Mulinia). This flight from predation seems to be a strong secondary factor controlling the distribution of some estuarine mollusks. Shell damage due to preda- tion by Callinect.es, the blue crab, and possibly skates or rays was observed on some specimens if Mercenaria and Mulinia, Bivalves common in the upper part of the in- tertidal zone attach to solid substrata by means of a byssus (Geukensia, Ischadium) or by cemen- tation (Crassostrea). Littorina occurs in great abundance in the fringe marsh where it clings to Spartina. Large bivalves Mercenaria, Mya, and Tagelus are most abundant on sandy substrata capable of supporting their body mass. Rapid burrowers Tagelus and Mya are abundant in area of shifting substrata such as shallow sub- tidal bars and intertidal areas. Crepidula and Anomia are common in subtidal environments where rocks, shell, or foreign objects provide a solid substratum for permanent attachment. The black organic mud is a very soupy substra- tum that contains a very sparse bivalve fauna. Three species of Macoma and Mulinia lateralis have small enough whole animal mass to be sup- ported by the mud (Stanley, 1970). Macoma is a deposit feeder that can utilize the abundant organic detritus of the black mud. Modified and Unmodified Estuary A cross-section of a composite unmodified shallow estuary is shown in Fig. 5A. This com- posite is based on relatively unmodified portions of Little Creek and on nearby estuaries that have undergone little modification. A typical profile includes a marginal fringing marsh with either muddy or sandy sediment depending on THE NAUTILUS January 30, 1985 Vol. 99(1) Substratum Type species samples 8 21 13 14 17 12 19 28 15 27 4 16 18 22 26 11 23 25 20 24 Geukensia demissa R AJA R C C Littorina irrorata A Crassostrea virginica R A A A R R R Ischadium recurva A Tagelus plebius A A C A A C C Mya arenaria C A A A R R llyanassa obsoleta C A A R C A R A R R Gemma gemma R A A R R R Polinices duplicatus R R Crepidula convexa R A A C C A Anomia simplex R R Urosalpinx cinerea R Mercenaria mercenaria R R A Nassarius vibex R Anadara cf A. ovalis R Acteocina canahculata R Macoma balthica R C C C R C A Muhnia lateralis RACACCA A A A Macoma phenax R R R R A M. tenta R R R C A- abundant, C= common, R=rare FIG. 4. Distribution of molluscan species in subenvironments. Double lines isolate species most characteristic for substrata at top of diagram. local current energy. Subtidal margins are usually muddy sand with a silt and clay content determined by tidal current and wave activity. Small islands are produced where intertidal bars are stabilized by Spartina. The sandy intertidal zone grades into muddy sand of the shallow sub- tidal environment which, in turn grades into black organic mud near the center of the basin. Black mud or muddy sand is also the typical bottom sediment in the tidal channels that pene- trate embayed marsh. In a natural estuary of the southeastern U.S. virtually the only solid substratum available is shell or wood fragments. The following types of physical modification by man have altered the substratum and mollus- can distribution in Little Creek: Type of Change or Structure 1. Shoreline stabilization and landfill (bulkheads and rip- rap) 2. Dredging new marsh channels into embayed marsh and basin margin 3. Bridge across estuary 4. Refuse Disposal 5. Dredge spoil disposal Affect on Subenvironment or Substratum Reduces basin area Eliminates fringing marsh habitat Introduces solid substrata (rock and pilings) Introduces sand, silt and clay (during construction) Increases area of black organic mud Increases organic content of muds in open estuary Alters basin form Increases velocity of tidal currents that distribute sand and scour deep channels Introduces solid substratum Slightly increases quantity of solid substrata Increases grain size of sediment Causes shoaling of bottom Vol. 99(1) January 30, 1985 THE NAUTILUS A) Estuary cross section {natural) Ltttonno Crossostreo Geukensia Channel deepened by tidal ecour B) Estuary cross section (urbanized) FIG. 5. Schematic estuary cross sections showing changes in molluscan habitats induced by man. Natural or undis- turbed estuary, A, urbanized estuary, B. Fig. 5B illustrates a composite cross-section of the natural estuary after urbanization. The basin has been reduced in area and much of the marsh habitat has been eliminated by "reclama- tion". This restricts the population size of the marsh fringe mollusks and affects the trophic dynamics and nutrient cycling in the system. Dredging or opening channels in embayed marsh allows tidal currents to remove coarser Spartina detritus and mats before it has thoroughly decayed or been modified by bac- teria (Odum and LaCruz, 1967). Excess organic detritus settles into muds of the quiet central regions of the estuary producing anoxic bottom conditions. This process occurs naturally, but it is exacerbated by man's activities in the marsh. Marsh areas serve as a buffer to the estuarine system in that they reduce runoff and trap fine sediment (Welsh and others, 1978). Removing marsh from the basin, while increasing surface runoff in adjacent watershed areas, allows large quantities of silt and clay to be introduced and to accumulate in regions of low tidal energy. The mud bottom in the mid-reaches of Little Creek, around station 20, is covered with a very fluid flocculent layer of silt and clay up to 0.5 m thick. Such soupy substratum is usually inhabitated only by very rare individuals of Macoma balthica. Due to the redistribution of sandy dredge spoil by tidal currents (Fig. 2) certain areas of Little Creek contain considerably more sand than would be expected in a natural estuary of com- parable size. A substantial sand shoal and exten- sive areas of intertidal and subtidal muddy sand have enlarged the habitat of molluscan species prefering a coarser substratum. This might be viewed as a benefit in that the commercially ex- ploitable species Mya armaria and Mercenaria mercenaria are more abundant on sandy bot- toms; however, unsatisfactory water quality hampers utilization of the shellfish resource (Owen and others, 1976). Almost all solid substrata that are permanent- ly exposed have been intensively colonized by mollusks. Crassostrea virginica is most abun- dant on introduced objects. There are no oyster "reefs" within Little Creek, but clumps of oysters established on foreign objects are dispersed over some intertidal and subtidal muddy sand flats. Crepidula convexa was found in great numbers on cans and other foreign metal substrata. Objects disposed of in the black mud provide support for molusks such as Crepidula that would not normally live in that subenvironment. Summary Human activities have significantly altered the distribution of mollusks in Little Creek by modifying basin configuration, hydrography, and substratum distribution. It appears that no molluscan habitat has been entirely eliminated, though all have been changed. The large area of Spartina marsh at the head of the creek is now protected by the Virginia Wetlands Act (Owen and others, 1976). Most dredging in the marsh predates this legislation. As the basin is now en- circled by urban development future areal con- striction is unlikely. In terms of the physical en- vironment, Little Creek estuary and its mollus- can community seems to be in a mature urban- ized condition. This study indicates the ease with which bot- tom types (substrata) may be characterized and mapped in a small estuary. The substratum dis- tribution map successfully delimits the habitats potentially available to molluscan assemblages even though an expected assemblage may not fully occupy areas of preferred substratum at the instant of sampling. Changes in bottom type THE NAUTILUS January 30, 1985 Vol. 99(1) associated with human acitivities in and around the estuary can be monitored easily and quickly, and the ultimate effect on molluscan species or assemblages can be predicted. LITERATURE CITED Bird, S. O. 1970. Shallow • marine and estuarine benthic molluscan communities from area of Beaufort, North Carolina. Amer. Assoc. Petrol. Geol. Bull. 54:1651-1676. Christian, R. R. and R. L. Wetzel. 1978. Interactions be- tween substrate, microbes, and consumers of Spartina detritus in estuarines. p. 93-113. In: M. L. Wiley (ed.) Estuarine Interactions. Academic Press, N.Y. 603 p. Davis, T. T. 1972. Effects on environmental gradients in the Rappahannock River estuary and the molluscan fauna. p. 263-290. In: B. W. Nelson (ed.) Environmental Frame- work of Coastal Plain Estuaries. Geol. Soc. Amer. Memoir 133. 619 p. Johnson, R. E. lDTli. Conceptual models of benthic marine communities, p. 148-159. In: T. J. M. Scopf (ed.) Models in Paleobiology. Freeman, Cooper, and Co., San Fran- cisco. 250 p. Odum, E. P. and A. A. de La Cruz. 1967. Particulate organic detritus in a Georgia salt marsh - estuarine ecosystem. p. 383-388. In: G. H. Lauff (ed.) Estuaries. AAAS Publ. 83. Wash., D.C. 757 p. Owen, D. W., L. M. Rogers and M. H. Peoples. 1976. Shore- line situation report cities of Chesapeake, Norfolk and Portsmouth. Va. Inst. Mar. Sci. Spec. Report 136. 87 p. Stanley, S. M. 1970. Relation of shell form to life habits of the bivalvia (Mollusca). Geol. Soc. Amer. Meinuir 125. 296 p. Welsh, B. L., J. P. Herring and L. M. Read. 1978. The ef- fects of reduced wetlands and storage basins on the stabil- ity of a small Connecticut estuary, p. 381-401. In: M. L. Wiley (ed.) Estuarine Interactions. Academic Press, N.Y. 603 p. MOLLUSCA OF FROG BAYOU, ARKANSAS Mark E. Gordon Department of Zoology University of Arkansas Fayetteville, Arkansas 72701 ABSTRACT Very few records ofmollnsks within the Arkansas River basin exist for Arkan- sas. Twenty-five species were collected from, Frog Bayou, a small tributary of the Arkansas River in western Arkansas. The fauna is dominated by Interior Basin species with minimal influence from Interior Highlands endemics. However, southern, affinities are represented. The majority of malacological investigations within the Arkansas River drainage have been conducted in Oklahoma, Kansas, and Colorado (e.g. Isely, 1925; Murray and Leonard, 1962; Wu, 1978), while the lower portions of the basin remain largely unexamined. Within Arkansas, only a few incidental references to the occur- rence of mollusks in this sytem have been pub- lished (e.g. Kraemer, 1976; Gordon, et al. 1980). The distribution of mollusks in Frog Bayou, a small Interior Highlands tributary of the Arkan- sas River in western Arkansas, is presented. Materials and Methods Frog Bayou drains portions of the extreme southern Ozark Plateaus and the northern slope of the Arkansas Valley (Ouachita Mountains province). The permanent flowing channel crosses the eastern half of Crawford County, Arkansas (Atoka sandstone). Substrates in upper Frog Bayou are quite rocky with large areas of exposed bedrock and rather high gra- dients. Middle portions are impounded by Lake Shepherd Springs (304 ha.) and Lake Fort Smith (212 ha.), while the mouth in inundated by Vol. 99(1) January 30, 1985 THE NAUTILUS Ozark Lake of the McClellan-Kerr Arkansas River Navigation System. Lower Frog Bayou may be quite sluggish and include mud and sand substrate (Arkansas River aluvium). Collections were made by hand at 15 access areas along the permanently flowing portion (Figure 1). Addi- tional records were obtained for Lake Fort Smith from ichthyoparasite slides prepared by Cloutman (1974). Voucher specimens are deposited at the University of Colorado Museum. Results Twenty-five species of mollusks were col- lected (Table 1). This included seven gastropods, 17 unionacean mussels, and Corbicula fluminea (Miiller). The fauna above the reservoirs con- Arkansas Riv«r FIG. 1. Location of sampling stations on Frog Bayou, Crawford County, Arkansas. Open circles represent stations at which no mollusks were found. sisted only of pulmonates, primarily Physella gyrina (Say). Glochidial preparations by Clout- man (1974) indicate that Quadrula pustulosa (Lea) and Anodonta grandis Say occur in Lake Fort Smith. No other mollusks were collected from either reservoir. Lake Fort Smith is an im- pediment to water flow which may often be in- termittent for several kilomenters downstream during late summer and early autumn. This area yielded only relicts of Proptera purpurata (Lamarck) and Lam.psilis hydiana (Lea). The majority of species were found from Rudy down- stream to the vicinity of Kibler. No mollusks were observed near the mouth. Discussion The molluscan fauna of Frog Bayou is com- posed primarily of widespread Interior Basin species. The only Interior Highlands endemic, Elimia potosiensis (Lea), oddly was found at the lowest sampling sight, rather than in rockier, higher gradient areas upstream representing more typical habitats for this species. A rather obscure species, Menetus sampsoni ("Ancey" Sampson), seems to be associated with the In- terior Highlands but its distribution has not been clearly defined and may be more wide- spread (see Burch and Tottenham, 1980). Fer- rissia cf. arkansasensis Walker also appears to be associated with the Interior Highlands. This form was synonymized under F. rivularis (Say) by Basch (1963) but seems to be a distinct species and may be found sympatrically with the latter. I have only been able to locate F. arkan- sasensis from a limited area of the Interior Highlands. The unionacean component of Frog Bayou is strictly an Interior Basin fauna. There are no In- terior Highlands endemics present and most are very common, widely distributed species. The presence of Leptodea leptodon (Rafinesque) establishes this species within the Arkansas River basin and geographically unites southern records (e.g. Wheeler, 1918; Isely, 1925) with northern populations. It also suggests that Call's (1885: see Scammon, 1906; Murray and Leonard, 1962) record may have been valid for Kansas (Neosho River). Additionally, a southern affinity is represented by three species: Prop- tera purpurata, Lampsilis hydiana, and L. satura (Lea). Proptera purpurata and L. 8 THE NAUTILUS January 30, 1985 Vol. 99(1) TABLE 1. Mollusca of Frog Bayou, Arkansas. (See Fig. 1 for station localities. Station: 1 2 3 4 5 6 7 a • 10 Class Gastropoda Family Pleuroceridae Elijnia potosiensis (Lea) X Family Lymnaeidae Fossaria obrussa (Say) X Family Physidae Physella gyrina (Say) X X X Family Planorbidae Menetus sampsoni ("Ancey" Sampson) X Helisoma anceps (Menke) X Family Ancylidae Ferrissia rivularis (Say) X Ferrissia cf. arkansasensis Walker X X X Class Bivalvia Family Amblemidae Subfamily Ambleminae Fusconaia flava (Rafinesque) X X X X X Quadrula pustulosa (Lea) X X X X Tritoqonia verrucosa (Rafinesque) X X X X X Amblema plicata (Say) X Subfamily Lampsilinae Obliquaria reflexa Rafinesque X X Actinonaias ligamentina (Lamarck) X X X X Truncilla truncata Rafinesque X X Leptodea fragilis (Rafinesque) X Leptodea leptodon (Rafinesque) X Proptera purpurata (Lamarck) X X X X Lampsilis teres (Rafinesque) X X X Lampsilis hydiana (Lea) X X X X X Lampsilis satura (Lea) X X X X Family Unionidae Subfamily Anodontinae Anodonta grandis Say X Lasmiqona costata (Rafinesque) X X Alasmidonta marginata1 (Say) X Subfamily Strophitinae Strophitus undulatus (Say) X X Family Corbiculidae Corbicula fluminea (MUller) X X X X Strophitini Gordon (1981) is elevated to subfamilial status. hydiana appear to replace P. alata (Say) and L. radiata siliquoidea (Barnes), respectively, in the south. Lampsilis satura is closely related to (and often confused with) L. ventricosa (Barnes), representing a southern clinal varia- tion probably fitting within the model presented by Cvancara (1963). While these three species are members of the Interior Basin fauna, they only range north to approximately 38°30' N. latitude and have colonized Gulf coastal systems east and west of the Mississippi River. Thus, the Arkansas River appears to have served as a cor- ridor through the Interior Highlands for disper- sal of both common Interior Basin species and a more restricted southern component. Acknowledgments This study was partially funded by a grant from the University of Arkansas Foundation, Inc. and was adapted from a thesis submitted in partial fulfillment of a M.S. degree, University of Arkansas. LITERATURE CITED Basch, P. F. 1963. A review of the recent freshwater limpet snails of North America. Bull. Mus. Comp. Zool. 129: 399-461. Burch, J. B. and J. L. Tottenham. 1980. North American freshwater snails: species list, ranges and illustrations. Walkerana 1:81-215. Call, R. E. 1885. Contributions to a knowledge of the fresh- water Mollusca of Kansas, III: Fresh-water bivalves. Bull. Washburn Coll. Lab. Nat. Hist. 1:93-97. Cloutman, D. G. 1974. Parasite community structure of selected game fishes related to season and water quality in Lake Fort Smith, Arkansas. Unpublished M.S. thesis, University of Arkansas-Fayetteville. 124 pp. Cvancara, A. M. 1963. Clines in three species of Lampsilis (IVlecypnda: I'nionidae). Malacologia 1:215-226. Gordon. M. E. 1981. Recent Mollusca of Arkansas with annotations to systematics and zoogeography. Pror. Ark. Acad. Sci. 34(1 980): 58-62. Vol. 99(1) January 30, 1985 THE NAUTILUS Gordon, M. E., L. R. Kraemer and A. V. Brown. 1980. Unionacea of Arkansas: historical review, checklist, and observations on distributional patterns. Bull. Am. Malacol. Union 1979:31-37. Isely, F. B. 1925. The fresh-water mussel fauna of eastern Oklahoma. Proc. Okla. Acad. Sri. 4:43-118. Kraemer, L. R. 1976. An evaluation of the effects of dredg- ing within the Arkansas River Navigation System, vol. IV: the effects upon the benthic associations. Ark. Water Resources Res. Center Pub. 46:1-357. Murray, H. D. and A. B. Leonard. 1962. Handbook of unionid mussels in Kansas. Univ. Kans. Mus. Nat. Hist. Misc. Pub. 28:1-184. Scammon, R. E. 1906. The Unionidae of Kansas, part 1. Univ. Kans. Sri. Bull. 3:279-373. Wheeler, H. E. 1918. The Mollusca of Clark County, Arkan- sas. The Nautilus 31:109-125. Wu, S.-K. 1978. The Bivalvia of Colorado, part 1: the finger- nail and pill clams (Family Sphaeriidae). Nat. Hist. Invent. Colo. 2:1-39. A NEW SPECIES OF PYGMAEPTERYS VOKES FROM THE WESTERN PACIFIC (GASTROPODA: MURICIDAE) Anthony D'Attilio and Barbara W. Myers Department of Marine Invertebrates Natural History Museum P.O. Box 1390 San Diego, California 92112 ABSTRACT A new species q/Tygmaepterys, P. bellini, from off Okinawa and the Philippine Islands, is described. Comparison is made with P. funafutiensis (Hedley, 1899), and P. philclover (Houart, 1984), both western Pacific congeners. Vokes (1978) erected Pygmaepterys as a sub- genus of Pterynotus Swainson, 1833, describing this subgenus as small for a Pterynotus, with six winged varices, strong spiral cords and numer- ous axial lamellae; the aperture denticulate on the outer lip and "occasionally small denticles on the inner lip." She designated Pygmaepterys alfredensis (Bartsch, 1915) as the type species. P. alfredensis is a small six-mm specimen, very worn, with the early whorls and varices eroded. The shoulder is concave and the suture deeply impressed. There are 12 major cords on the body whorl. P. alfredensis is illustrated in Vokes (1978) pi. 7, figs, la, lb, 2a and 2b and in Vokes and D'Attilio (1980) pi. 2, figs, la and lb. The type locality is Port Alfred, South Africa. Ap- parently additional specimens have not been found of this species. Bartsch (1915) in his original description of P. alfredensis mentions no denticles on either the inner lip or the outer lip of the aperture. Vokes and D'Attilio (1980) described three new species of Pygmaepterys and assigned one other species to the genus, but expressed some doubts regarding the qualitative character of the inner lip denticles. As a result of the species studied for this paper we have concluded that although denticles in the outer lip are a good character of the genus, Pygmaepterys, the presence or absence of nodes or denticles on the inner lip or col- umella is inconsistent. The following abbreviations are used: SDNHM - San Diego Natural History Museum AMNH - American Museum of Natural History, New York. Family Muricidae Rafinesque, 1815 Subfamily Muricopsinae Radwin and D'Attilio, 1971 Genus Pygmaepterys Vokes, 1978 Type species: Murex alfredensis Bartsch, 1915, by original designation. Pygmaepterys bellini new species Figs. 1-4, 9, 12 Description: Shell small, fusiform; spire elon- gate with four convex post-nuclear whorls; 10 THE NAl'TIU'S January 30, 1985 Vol. 99(1) FIGS. 1 and 2. Pygmtieptcrys hellim D'Attilio and Myers. Dorsal (1) and apertural (2) views of holotype, SDNHM 83065. Okinawa, Japan. 9.9 mm x 5.5 mm. FIGS. 3 and 4. Pygmaepterys bellini D'Attilio and Myers. Dorsal (3) and apertural (4) views of paratype SDNHM 83067a. Philippine Islands. 12.0 mm x 5.5 mm. FIGS. 5 and 6. Pygmaepterys philcloveri (Houart, 1984). Dorsal (5) and apertural (6) views. SDNHM 83068. 13.7 mm x 8.00 mm. FIGS. 7 and 8. PygiititeptrrysfinKifutiettsis (Hedley, 1899). Dorsal (7) and apertural (8) views of specimen from the Donald Pisor collection. 12.0 mm x 7.2 mm. suture impressed. Protoconch of one and one- half smooth convex whorls, white in color. Aper- ture narrowly ovate; anal sulcus broadly U-shaped; inner lip mostly appressed except very slightly erect anteriorly with one strong node on columella at entrance to the canal; en- tire columella stained dark-brown. Outer lip wavy, reflecting the external spiral cords with six strong nodelike denticles within. Siphonal canal open, tapered and recurved. Three distal portions of previous canals terminate on siphonal fasciole. Six axial varices per whorl ir- regularly descend relative to axis of shell. A few well-defined erect lamellae occur between the varices and a few regularly-spaced translucent lamellae crowd against the leading side of the varix. These lamellae undulate over the spiral sculpture giving a scabrous appearance to the shell. Eleven strong regularly-spaced spiral cords with equally wide interspaces occur on the body whorl; intermediate minor spiral cords oc- cur only on the varical flange. The color of shell varies from translucent white to white with one to three brown stripes on the body whorl. Type Material: Holotype SDNHM 83065 from Okinawa, Ryukyu Islands, Japan (Figs. 1, 2, 9, 12). Paratype SDNHM 83066a and Paratype 83066b from Okinawa. Paratype SDNHM 83067a from the G. Everson collection from Philippine Islands (Figs. 3, 4). Paratype SDNHM 83067b from B. Myers collection from Philippine Islands. Paratype AMNH 213704 from Okinawa. Type Locality: 52 meters depth off Okinawa, Ryukyu Islands, Japan. Dimensions (in mm): Length Width SDNHM 83065 9.9 5.5 SDNHM 83066a 10.2 4.8 SDNHM K30661, 7.9 4.9 SDNHM 83067a 12.0 7.0 SDNHM 83067b 9.9 5.5 AMNH 213704 8.0 4.5 Vol. 99(1) January 30, 1985 THE NAUTILUS 11 Etymology: Named for Mr. Philip Bellin of Hawaii who first collected specimens off Okinawa, Japan. Discussion: Of the six specimens studied, three have immature lips with no nodes or denti- cles. Paratype 83066a has six denticles on the outer lip and three nodes on the anterior wall of the columella. Paratype 83066b has seven denti- cles on the outer lip and one node on the col- umella at the entrance to the siphonal canal. Comparison is made with P. funafutiensis (Hedley, 1899). See Table 1. The type specimen of P. funafutiensis is from Funafuti Atoll, Ellice Islands and is 9 mm in height. Specimens in the San Diego Natural History Museum, lot #71304, dredged from 183 m in Pokai Bay, Oahu, Hawaii, consist of four specimens, the larger of which is 9.8 mm x 6.2 mm and two fragments. Both the type specimen from Ellice Islands and the larger specimen from Hawaii are illustrated in Vokes and D'Attilio (1980), pi. 2, figs. 4, 5a and 5b. P. funafutiensis has a heavier coarser shell with six axial varices and five postnuclear whorls. There are five strong spiral cords on the body whorl with wide interspaces, each inter- space with five to seven incised lines. P. bellini has 11 regular, moderately strong cords with equal interspaces and intermediate cords only on the varical flange. Growth lamellae in P. funafutiensis are close-set and three to four times as numerous as in P. bellini. P. funafu- tiensis has five apertural denticles on the outer lip; the first and second denticles posteriorly are most prominent. P. bellini has six denticles of even strength. The columella of P. funafutiensis lacks any trace of the brown stain prominent in P. bellini. The color of P. funafutiensis is tan with a diffused brown band subsuturally and one at the base of the body whorl. A specimen of P. funafutiensis from the Philippine Islands in the collection of Donald Pisor of San Diego, Califor- nia, measures 12 mm x 7.2 mm (Figs. 7, 8, 11, 14). This specimen does not differ in any essen- tial respect from those from Hawaii except that TABLE 1. Comparison of Pygmaepterys bellini new species, P. philcloveri Houart and P. funafutiensis (Hedley). P. bellini P. philcloveri P. funafutiensis Color: All white or white with brown bands and with brown stain on columella Rust brown with pale brown band; columella white, no brown stain Tan with brown band, columella white, no brown stain Shape: Fusiform, spire elongate Fusiform, spire moderately elongate Fusiform, spire moderately elongate Size To 12.0 mm x 7.0 mm To 13.7 mm x 8.0 mm To 12.0 mm x 7.2 mm Protoconch: White, 1V2 blunt whorls Tan, 1% conical whorls Brown. IV2 low depressed whorls Postnuclear whorls: Four Five Five Varices: Six, irregularly descending Six, regularly descending Six, regularly descending Peristome: Simple ovate, inner lip appressed slightly erect anteriorly Irregularly ovate, inner lip erect, flattened posteriorly Simple ovate, inner lip mostly appressed Anal sulcus: Shallow and broad Moderately broad and deep Broad and deep Varical flange: Very weakly lamellose reflect- ing the numerous spiral cords Entirely scabrously lamellose reflecting the numerous spiral cords Five deep grooves, reflecting the five strong spiral cords Suture: Impressed Moderately impressed Moderately impressed Denticles: Six on outer lip, one on columella Six on outer lip, five on columella Five on outer lip, two on columella Growth lamellae: A few erect lamellae appressed over the spiral cords Numerous erect lamellae appressed over the spiral cords Very numerous lamellae appressed over entire shell Spiral cords: Eleven moderately strong cords terminating at end of siphonal canal Twelve major cords terminat- ing at tube-like portion of siphonal canal Five major cords followed by five minor cords terminating at end of siphonal canal 12 THE NAUTILUS January 30, 1985 Vol. 99 (1) FIG. 9. Detail drawing of protoconch of P. bellini. Holotype SDNHM 83065. FIG. 10. Detail drawing of protoconch of P. philcloveri. SDNHM 83068. FIG. 11. Detail drawing of protoconch of P. fmwfutiensis. Donald Pisor collection. FIG. 12. Detail drawing of aperture of P. bellini. Holotype SDNHM 83065. FIG. 13. Detail drawing of aperture of P. philcloveri. SDNHM 83068. FIG. 14. Detail drawing of aperture of P. junafutiensis. Donald Pisor collection. FIG. 15. Detail drawing of operculum of P. philcloveri. SDNHM 83068. nodes on the columella number two instead of three. A second new species of Pygmaepterys had been under study by us. A description of this species has recently been published by Houart (July, 1984). The description prepared by us follows: Pygmaepterys philcloveri (Houart, 1984) 1984 Poirieria (Pazinotus) philcloveri Houart, Informations, series 12, nos. 2, 3, pp. 127-130. (off Samal Id., Davao, Mindanao Id. Philippines). Figs. 5, 6, 10, 13, 15 Description: Shell strongly fusiform, spire moderately elongate, suture moderately im- pressed. Protoconch of one and three-fourths conical, convex smooth, pale brown whorls; five post nuclear whorls. Anal sulcus u-shaped and deep. Inner lip appressed posteriorly, strongly erect two- thirds distance from siphonal canal; five elongate denticles occur on lower portion of columella, the most anterior denticle situated directly above the entrance to siphonal canal. Outer lip erect, wavy, reflecting the external spiral sculpture with six denticles arranged as follows: two small denticles posteriorly followed by a very large denticle midway, two slightly smaller denticles below and a large bifid denticle above entrance to siphonal canal. Siphonal canal open, broad and tapering distally becoming recurved and tubelike. Three distal portions of previous canals terminate on siphonal fasciole. Seven axial varices on spire diagonally descend to the body whorl where the varices number only six. Varices blade-like continue above the shoulder and abut the suture. Entire surface of shell with very fine scabrous close-set axial growth lamellae. Spiral sculpture of 12 cords starting at shoulder; first five prominent and somewhat spinose at the varical margins with prominent open spines at the shoulder; inter- spaces wide; remaining seven cords narrower and more close-set with diminishing inter- spaces. Operculum typically Muricopsinae. Color: Rust-brown with a pale band starting at the shoulder and encompassing the first three cords. The rust-brown is much darker below the suture. The distal portion of the canal is gray- white and the aperture is white. Length of shell 13 mm. Discussion: P. philcloveri in comparison with P. bellini has a slightly larger, more robust Vol. 99(1) January 30, 1985 THE NAUTILUS 13 shell. See Table 1. The shell is distinguished most significantly in the apertural characters. The aperture of P. philcloveri is irregularly ovate and the inner lip strongly erect over most of its length. There is a deep anal sulcus in com- parison to the broad shallow sulcus of P. bellini. Although the number of denticles is the same, the arrangement and size differ in that P. bellini has six denticles of equal strength, while P. philcloveri has two small denticles posteriorly followed by a very large denticle midway on the outer lip with two smaller denticles following and one large bifid denticle above the entrance to the siphonal canal. P. bellini has six varices ir- regularly descending to the body whorl, while P. philcloveri has seven regularly descending axial varices on the spire reduced to six on the body whorl, the varix lacking is between the final varix and the preceding one. The entire surface of P. philcloveri consists of fine, strong, close- set scabrous lamellae in contrast to the few translucent erect lamellae of P. bellini. The overall brown stain on the columella of P. bellini is not found in P. philcloveri. P. bellini has a white shell with three brown bands and P. phil- cloveri has a rust brown shell with a pale brown band. P. funafutiensis (Hedley, 1899) differs from P. philcloveri in the protoconch which is depressed and not conical. The inner lip of P. funafutiensis is mostly appressed, not erect as in P. phil- cloveri and there are five denticles on the outer lip of more or less equal strength in contrast to the six denticles of unequal size and strength of P. philcloveri. The spiral sculpture of P. funafu- tiensis consists of five very strong major cords with five minor cords while P. philcloveri has 12 strong major cords. The growth lamellae of P. funafutiensis are very numerous and appressed over the entire shell, whereas in P. philcloveri the lamellae are erect and only appressed over the spiral cords. The leading side of the aper- tural varix of P. funafutiensis has five strong concave troughs, a reflection of the strong ex- terior cords. The apertural varix of P. phil- cloveri is regularly wavy reflecting the spiral cords. Acknowledgments We wish to thank the following: Mr. Philip Bellin of Hawaii for donating specimens of Pygmaepterys bellini new species to the Natural History Museum of San Diego; Mr. Gene Ever- son of Lauderhill, Florida, for donating his specimen of P. bellini from the Philippine Islands; Mr. Victor Dan of Manila, Philippine Islands, for allowing us to study his specimens of P. philcloveri and for donating a specimen to our museum; Mr. Robert Yin of La Jolla, Cali- fornia, for bringing the specimens of P. phil- cloveri to our attention; Mr. Donald Pisor of San Diego, California, for allowing us to study his very fine example of P. funafutiensis (Hedley,' 1899). We are grateful to Mr. David K. Mulliner for the photography used in this paper. Dr. William K. Emerson and Mr. Walter E. Sage, III of the American Museum of Natural History read a draft of the manuscript. LITERATURE CITED Bartsch, P. 1915. Report on the Turton collection of South African Marine Mollusks with additional notes on other South African Shells contained in the United States Museum. Bull. 91 USNM. 1-305 pp. 54 pis. Hedley, C. 1899. The Mollusca of Funafuti. Mem. Aust. Mus. 3(7):397-488, 49 figs. Pt. 1. Gastropoda. Houart, R. 1984. Poirieria (Pazinotus) philcloveri, a new species from the Philippine Islands (Gastropoda: Murici- dae: Muricinae). Informations 12(2-3): 127-130. 1 pi. Radwin, G. and A. D'Attilio. 1971. Muricacean supraspecific taxonomy based on the shell and radula. Echo 4:55-67. Rafinesque, C. S. 1815. Analyse de la nature, ou tableau du univers et des corps organises. Barravecchia, Palermo. Vokes, E. 1978. Muricidae (Mollusca: Gastropoda) from the eastern coast of Africa. Ann. Natal Mus. 23(2):375-418, 8 pis. Vokes, E. and A. D'Attilio. 1980. Pygmaepterys, a newly described taxon of Muricidae (Mollusca: Gastropoda) with description of three new species from the Cenozoic of the western Atlantic. Tulane Studies in Geo. and Paleo. 16(2):45-54, 2 pis. 14 THE NAUTILUS January 30, 1985 Vol. 99(1) MUREX HAMATUS HINDS, 1844, A LIVING WEST AMERICAN SPECIES ASSIGNED TO THE NEOGENE PACIPHILE GENUS, PTERORYTIS CONRAD (GASTROPODA: MURICIDAE). William K. Emerson Department of Invertebrates American Museum of Natural History New York, New York 10024 ABSTRACT Pterorytis hamatus (Hinds), an inhabitant of Ecuadorian and Peruvian waters, is the only known extant species of this muricacean genus. Pterorytis was widely distributed in the tropical western Atlantic during the Neogene. By the end of the Pliocene, however, the constituents of this Paciphile genus apparently became extinct in the western Atlantic, with P. hamatus surviving on the Pacific side of the Panamanian land bridge. The typological specimens o/Murex hamatus were examined, and a live-collected specimen was studied. On the basis of oper- cular, radular and shell characters, the assignment of this species to the muricid subfamily Ocenebrinae is confirmed. Some twenty-five years have passed since my review of the muricid genus Pterorytis appeared (Emerson, 1959). At that time the genus was believed to consist of extinct east American Neogene species. More than a decade ago, how- ever, Vokes (1971, pp. 56, 141, and Vokes in Keen, 1971, p. 536) recognized that a long- misunderstood species from Ecuador, described by Hinds in 1844 as Murex hamatus, was a living representative of this Paciphile genus. Previous- ly, Hinds' species was referred to other muricid genera, including Tritonalia, Ocenebra and Ceratostoma and was erroneously placed in the synonymy of Ceratostoma lugubre (Broderip, 1833), a species that also was originally de- scribed from Ecuador. Through the kindness of Carol Skoglund of Phoenix, Arizona, a specimen of Pteror^ytis hamatus, taken alive by shrimpers working out of San Pablo, Ecuador, was submitted to me for study. As the preservation of the soft parts of this specimen presented an opportunity to establish the taxonomic placement within the Muricidae of this rarely found species, the pre- sent study was undertaken. Family Muricidae Rafinesque, 1815 Subfamily Ocenebrinae Cossmann, 1903 Genus Pterorytis Conrad, 1862 Pterorytis hamatus (Hinds, 1844) Figs. 1-5, 7-9 Murex hamatus Hinds, 1844a, p. 128; Hinds, 1844b, p. 8, pi. 3, figs. 11, 12; Reeve, 1845, Murex, sp. 119, pi. 27, fig. 119 ("Museum Belcher"); Sowerby, 1879, Murex. sp. 203, p. 44, pi. 16, fig. 159 ("Voy. Sulph., p. 8"). Murex lugubris Broderip, Tryon, 1880, p. 124, pi. 37, fig. 439 only; Keen 1958, p. 357, in part. Not M. lugubris Broderip, 1833. Tritonalia hamata (Hinds), Dall, 1909, p. 220, "Guayaquil, Ecuador, and south to Paita, Peru"); Smith, 1939, p. 15, (cites Dall's distributional data). Ceratostoma hamata (Hinds), Keen, 1966, p. 269, pi. 46 fig. 11 ("figured syntype, from Belcher coll. to S. Hanley to H. Harvey; also figured by Reeve, [1845]"). Pterorytis hamatus (Hinds), Vokes, 1971, pp. 56, 141; Keen, 1971, p. 536, fig. 1039 ("BM Syntype", p. 951); Fair, 1976. p. 47, pi. 23, fig. 360 ("BM(NH) Holotype (EH V[okes])", p. 131). Ocenebra? hamata (Hinds), Radwin and D'Attilio, 1976, pp. 121. 122, pi. 14. fig. 2 ("off Peru, Inst. Del Mar, Peru," p. 259). Type locality: "Bay of Guayaquil, [Ecuador], from a muddy floor, in twenty-one fathoms" [38 m]. Known range: Golfo de Guayaquil (type speci- mens) and off San Pablo, Guayas Province (AMNH 213692), Ecuador, and Paita, Peru (Dall, 1909, p. 220; cited specimens were not Vol. 99(1) January 30, 1985 THE NAUTILUS 15 FIGS. 1-3. Pterorytis hamatus (Hinds, 1844), off San Pablo, Guayas Province, Ecuador (AMNH 213692); height = 38.6 mm. FIGS. 4 and 5. Original figures of Murex hamatus (Hinds, 1844b, figs. 11, 12); height = 29.2 mm. found in the NMNH collection, teste J. Rosewater, August 10, 1984). Diagnosis: Shell rhomboid in outline, 23 mm to 40 mm in height. Spire elongated, of 3V2 nuclear whorls; 4 post nuclear whorls. Six raised, spiniform varices per whorl ornamented with slightly recurved laciniations and one or two major ribs on faces of varices. Aperture oval, with an acute labial tooth anteriorly, marked here and on the previous varices of body whorl by a V-shaped notch behind varical tooth. Canal short, closed, grooved behind. Color pale- yellow to tan (modified after Fair, 1976, p. 47). Radular characters: Typical of Ocenebrinae; compare our Figure 7 with our Figure 6 of the radular dentition of Ocenebra erinaceus (Linne, 1758), the type species of Ocenebra Gray, 1847. Opercular characters: Ocenebrine, see Figs. 8, 9. Remarks: The larger of the two "syntypes" of Murex hamatus in the British Museum (Natural History) (1907.12.30.134, here illustrated, Figures 4, 5), measures 29.2 mm (sans nucleus). This specimen (29.2 mm in length) appears to be the one figured by Hinds (1844b, pi. 3, Figs. 11, FIGS. 6 and 7. 6, Radular dentition of Ocenebra erinaceus (Linne, 1758), after Radwin and D'Attilio, 1976, fig. 73. 7, Radular dentition of Pterorytis hamatus (Hinds, 1844), (AMNH 213692), drawing by Anthony D'Attilio. left side, central tooth; right side, 1 lateral tooth. 16 THE NAUTILUS January 30, 1985 Vol. 99(1) FIGS. 8 and 9. Operculum of Pterorytis ham.atus (Hinds, 1844), (AMNH 213692), left side, internal view; right side, external view; drawings by Anthony D'Attilio; greatly enlarged. 12) and Reeve (1845, Murex, pi. 27, Fig. 119), despite the fact that Hinds (1844a, p. 128) cites 13V2 English lines for the axis of the shell [ = 28.5 mm]. 13.5 French lines would be 30.3 mm. Keen (1966, p. 269) translated it to 34 mm. Keen (op. cit.) also recorded a second specimen, a topotype, in the general collection of the British Museum (1842.1.22.418), which Hinds in 1842 had labeled "Murex, sp.". It is a juvenile, measuring 23.2 mm in height, with an immature outer lip. The present specimen from off San Pablo, Ecuador (AMNH 213692, here illus- trated, Figures 1-3, 7-9), is a larger (38.6 mm), more robust example of this species. The specimen identified as ?Ocenebra hamata by Radwin and DAttilio (1976, pi. 14, Fig. 2, from "off Peru") may represent another species. The shell is larger (66.8 mm in height), with the labial tooth situated medially, and it is colored a darker tan, tinged with brown. No other specimens of this species were located in any of the leading U.S. museum col- lection nor in such private collections as that of Helen DuShane and Donald R. Shasky. The failure to find additional specimens in these col- lections attests to the apparent rarity of this species. Systematics and Zoogeography I'trrorytis hintmtus appears to be most closely related to the type species of Pterorytis, P. um- brifer (Conrad," 1832, p. 17, pi. 3, Fig. 1; Olsson and Harbison, L953, pi. 35, Fig. 2; Emerson, 1959, Fig. 1), a species not uncommonly found in Pliocene deposits (Yorktown formation) of Virginia. Both species have a shell well-marked by a V-shaped indentation behind the acute labial tooth, as well as six foliated and spiniform varices. Pterortyis hamatus is, therefore, referable to Pterorytis (sensu stricto) and is the only known survivor of this Paciphile genus, which during the Neogene flourished in the tropical western Atlantic. The other extinct species of Pteroi'ytis (see Olsson and Harbison, 1953, p. 252; Emerson, 1959, p. 4; Olsson and Petit, 1964, p. 549; Vokes, 1971, p. 141) have been referred to the subgenus Neurarhytis Olsson and Harbison (1953, p. 252) of which P. jluviana (Da\\, 1903, p. 1633, pi. 60, Figs. 20, 21; Emerson, 1959, Fig. 2) is the type species. These taxa have heavier shells of moderate size, with four wide, terminally recurved, finely foliated varices per whorl and a weakly devel- oped labial tooth without a prominent labial suture. Pterorytis (Mierorhytis) pecki (Emerson, 1959, p. 6, Fig. 4) from the Miocene of Veracruz, Mexico, may be referable to the genus Cerato- stoma Herrmannsen, 1846, type species C. nut- talli (Conrad, 1837, p. 264, pi. 20, Fig. 22), as Vokes (1971, p. 125) has indicated. However, P. peeki, the type species of Mierorhytis Emerson (1959), does possess a marginal indentation below the labial tooth, which is characteristic of Pterorytis, and has a shorter spire than typical species of Ceratostoma. At the present time the geographical range of Ceratostoma is from Japan to northern Mexico (Cape San Lucas, Baja California Sur). Vokes (1964, p. 23; 1974, p. 8), however, reports in the Miocene of Silverdale, North Carolina (Trent marl of Richards, 1943) the presence of several amphi-North Pacific muricid genera, including Ceratostoma, that are no longer living in the western Atlantic. During the Neogene, the genus Ceratostoma is known to have been pre- sent in western Atlantic waters (North Carolina and possibly from Vera Cruz, Mexico), as well as in northeastern Pacific waters (Mio-Pliocene of California, Hall, 1959). Acknowledgments I am deeply indebted to Carol Skoglund for her kindness in calling to my attention and Vol. 99(1) January 30, 1985 THE NAUTILUS 17 donating her specimen to the AMNH. I thank John Taylor (BM(NH)) for the loan of Hinds' typological specimens and Anthony D'Attilio and Barbara Myers (SDNHM) for providing the line drawings of the radular dentition and the operculum and for preparing the radular mount, respectively. The following friends and col- leagues assisted by searching their collections for specimens: Robert Robertson and Mary A. Garback (ANSP), Terrence M. Gosliner (CAS), James H. McLean (LACMNH), Ruth D. Turner and David H. Backus (MCZ at Harvard), Joseph Rosewater (NMNH), Anthony D'Attilio (SDMNH), Helen DuShane of Whittier, CA, and Donald R. Shasky of Redlands, CA. George and Wylda Stephens of Virginia Beach, VA, and Richard E. Petit of North Myrtle Beach, SC, generously provided fossil specimens of Pterorytis. I also acknowledge the contributions of my AMNH colleagues: Walter E. Sage, III for technical services, and Peter Harries and Jeff Teitelbaum for the photography. LITERATURE CITED Broderip, W. J. 1833. Characters of new species of Mollusca and Conchifera, collected by Mr. Cuming. Proc Zool. Soc. London, for 1832, pp. 173-179 (Jan. 14, 1833). Conrad, T. A. 1832. Fossil shells of the Tertiary formations of North America. Philadelphia, vol. 1, pp. 1-28, pis. 1-14. 1837. Descriptions of new marine shells from upper California, collected by Thomas Nuttall, Esq. Jour. Acad. Nat. Sci. Philadelphia, vol. 7, pp. 227-268, pis. 17-20. 1862. Catalogue of the Miocene shells of the Atlantic slope. Proc. Acad. Nat. Sci. Philadelphia, vol. 14, pp. 559-582. Dall, W. H. 1903. Contributions to the Tertiary fauna of Florida. Trans. Wagner Free Inst. Philadelphia, vol. 3, pt. 4, pp. l-xiv + 1219-1654, pis. 48-60. 1909. Report on a collection of shells from Peru, with a summary of the littoral marine Mollusca of the Peruvian zoological province. Proc. U.S. Nat. Mus.. vol. 37, no. 1704, pp. 147-294, pis. 20-28. Emerson, W. K. 1959. The gastropod genus Pterorytis. Amer. Mus. Novitates, no. 1974, 8 pp., 4 figs. Fair, R. H. 1976. The Murex book: an illustrated catalogue of Recent Muricidae (Muricinae, Muricopsinae, Ocenebrinae). Honolulu, 138 pp., 56 text figs., 21 pis. Hall. C. A. Jr. 1959. The gastropod genus I'iratostoma. Jour. Paleont., vol. 33, no. 3, pp. 428-434, 4 text figs. pis. 61-63. Herrmannsen, A. N. 1846. Indicis generum malacozoorum primordia, Kassel, vol. 1. pp. 1-232, [pp. 233-637, 1847]. Hinds, R. B. 1844a. Descriptions of new species of Scalaria ■and Murex. from the collection of Sir Edward Belcher, CB. Proc. Zool. Soc. London, for 1843, pp. 124-129 (March, 1844). 1844b. The zoology of the voyage of H.M.S. Sulphur under the command of Capt. Sir Edward Belcher . . . during 1836-1842, London, Mollusca, pt. 1, pp. 1-24, pis. 1-7 (July, 1844). Keen, A. M. 1958 Sea shells of tropical west America. Stanford, California, xi + 624 pp., illus. 1966. West American mollusk types in the Brit- ish Museum (Natural History) II. Species described by R. B. Hinds. The Veliyer. vol. 8, no. 4, pp. 265-275, 6 text figs., pis. 46-47. 1971. Sea Shells of tropical west America, 2nd ed., Stanford, California, xiv + 1,064 pp., illus. Olsson, A. A., and Anne Harbison. 1953. Pliocene Mollusca of southern Florida. Monogr. Acad. Nat. Sci. Philadel- phia, no. 8, pt. 1, pp. 27-361, pis. 1-65. Olsson, A. A., and R. E. Petit. 1964. Some Neogene Mollusca from Florida and the Carolinas. Bull. Amer. Paleont., vol. 47, no. 217, pt. 2, pp. 527-574, pis. 77-83. Radwin, G. E., and A. D'Attilio. 1976. Murex Shells of the World, an illustrated guide to the Muricidae, Stanford, California, 284 pp., 98 text figs., 32 pis. Reeve, L. A. 1845. Conchologia Iconica, or illustrations of the shells of molluscous animals, London, Monograph of the genus Murex, text + Murex pis. 1-34 [pi. 27, Aug. 1845], Richards, H. G. 1943. Additions to the fauna of the Trent marl of North Carolina. Jour. Paleont., vol. 17, no. 5, pp. 518-526, pis. 85, 86. Smith, Maxwell. 1939. An illustrated catalogue of 'the Recent species of the rock shells. Muricidae, Thaisidae, and Coral- liophilidae, Lantana, Florida, 83 pp., text figs, a-z, 21 pis. Sowerby, G. B. II. 1879. Thesaurus Conch yliorum, or mono- graphs of the genera of shells. London, vol. 4, Monograph of the genus Murex Linnaeus, pts. 33-35, 55 pp., pis. 380-403 [Murex, pis. 1-24]. Tryon, G. W., Jr. 1880. Manual ofConchology, ser. 1, vol. 2, Muricidae, Purpuridae, Philadelphia, 289 pp., 70 pis. Vokes, E. H. 1964. Supraspecific groups in the subfamilies Muricinae and Tritonaliinae (Gastropoda: Muricidae). Malaeologia, vol. 2, no. 1, pp. 1-41, pis. 1-3. 1971. Catalogue of the genus Murex Linne (Mollusca: Gastropoda; Muricinae, Ocenebrinae). Bull. Amer. Paleont., vol. 61, no. 268, 141 pp. 1974. A new species and subgenus of Australian Demomurex (Gastropoda: Muricidae). Jour. Malac. Soc. Australia, vol. 3, no. 1, pp. 1-14, pis. 1-3. 18 THE NAUTILUS January 30, 1985 Vol. 99(1) CORBICULA FLUMINEA (BIVALVIA: CORBICULIDAE) IN THE STATE OF WASHINGTON IN 1937, AND IN UTAH IN 1978 Clement L. Counts, III College of Marine Studies University of Delaware Lewes, Delaware 19958 Washington The exotic Asiatic bivalve, Corbicula Jluminea (Muller, 1774) was first detected in North America at Nanaimo, Vancouver Island, British Columbia, in 1924 (Counts, 1981). The first report of C. jluminea in United States waters is that of Burch (1944) for specimens collected along the Columbia River at Knappton, Pacific County, Washington, in 1938. These are the earliest published records for C. Jluminea in North America (McMahon, 1982, 1983; Counts, 1983). A survey of the Corbiculidae collections held in the Department of Malacology of the Los Angeles County Museum of Natural History (LACM), conducted in June 1984, revealed a lot of Corbicula Jluminea collected in April 1937 at Raymond, Pacific County, Washington (LACM 64359). The label accompanying the specimens states "Introduced from Japan. Immaculate Heart Collection. A. Burch". It does not specify a body of water as a collection locality. No details are available on either the Immaculate Heart Collection or the collector. The shape and color of the specimens is consistant with the "white form" described by Hillis and Patton (1982). A review of zoogeographic records for C. ihinmiiii in Washington found thai specimens were collected from the Willapa River at Ray- mond in 1971 (Counts, 1983) indicating that C. Jluminea has survived in this region of Washing- ton and suggesting that LACM 64359 may be representative of the population of origin. Although LACM 64359 does not significantly alter the date of the introduction of Corbicula Jluminea into United States waters, it is signifi- cant since it reinforces the hypothesis of a west coast introduction during the 1920's-1930's (Britton and Morton, 1979). Acktmtrlnhin/cnts: I would like to thank Mr. C. Clifton Coney and Dr. James H. McLean, Los Angeles County Museum of Natural History, for their assistance. Utah The Asiatic bivalve, Corbicula Jluminea (Muller, 1774) has been reported from Utah only in general geographic terms (Cherry, et aL, 1980a, b; McMahon, 1982, 1983). These reports are in the nature of either lists of states where C. Jluminea does or does not occur or United States maps with the State of Utah colored to indicate the presence of the species. No precise locality descriptions have been published for C. Jluminea in Utah. A survey of 26 malacological collections held in museums throughout the United States, conducted between 1979 and 1982 failed to reveal any specimens collected in Utah (Counts, 1983). A survey of the malacological collections of The Ohio State University Museum of Zoology (OSUM) conducted in June 1984 revealed two lots of Corbicula Jluminea collected in Utah. Both lots (OSUM 52430 and OSUM 52431) were collected in the Sevier Reservoir (also known as Yuba Reservoir), 15.2 km northeast of Scipio, Juab County, Utah on 4 July 1978 by Richard L. Denton (Fig. 1). The shape and color of the specimens is consistant with the "white form" of Hillis and Patton (1982). The Sevier River flows approximately 520 km from the Paunsaugunt Plateau of southwestern Utah north to Juab County where it then flows southwest to Sevier Lake. The river is located in the Great Basin and thus has no outlet to the oceans. Further, there is no connection with any other river in which Corbicula Jluminea is known to exist. This indicates that C Jluminea was introduced into the Sevier River by means other than normal movements of the bivalves in the substratum. Zoogeographic studies of C. ih < in i in a reveal the nearest known population is Vol. 99(1) January 30, 1985 THE NAUTILUS 19 H FIG. 1. Location of Corbicula fluminea in the Sevier River, Utah (Scale bar = 100 km). located in Lake Meade of Arizona-California- Nevada (Counts, 1983). Whether the agent of in- troduction into the Sevier River was man or waterfowl is speculative at present. Acknowledgments: I would like to thank Dr. David H. Stansbery, The Ohio State University Museum of Zoology, for allowing me to examine their collections. Both of these researches were supported by the U. S. Nuclear Regulatory Commission (Contract No. NRC-03-84-063). LITERATURE CITED Britton, J. C. and B. Morton. 1979. Corbicula in North America: the evidence reviewed and evaluated. IN: Pro- ceedings of the First International Corbicula Symposium, J. C. Britton, Ed. Texas Christian University Research Foundation (Fort Worth), pp. 250-287. Burch, J. Q. 1944. Checklist of west American mollusks. Minutes, Concol. Club Southern California 38:18. Cherry, D. S.. J. Cairns, Jr. and R. L. Graney. 1980a. Asiatic clam invasion: causes and effects. Water Spectrum 12:18-24. Cherry, D. S., J. H. Rodgers, Jr., R. L. Graney and J. H. Cairns, Jr. 1980b. Dynamics and control of the Asiatic clam in New River. Virginia. Bulletin, Virginia Water Resources Center, 123:1-72. Counts, C. L., III. 1981. Corbicula fluminea (Bivalvia: Sphaeriacea) in British Columbia. The Nautilus 95(1): 12-13. 1983. Bivalves in the genus Corbicula Miihlfeld, 1811 (Mollusca: Corbiculidae) in the United States: sys- tematics and zoogeography. Ph. D. Dissertation. Univer- sity of Delaware, xxii + 451 pp. Hillis, D. M. and J. C. Patton. 1982. Morphological and elec- trophoretic evidence for two species of Corbicula (Bivalvia: Corbiculidae) in North America. American Midland Naturalist 108(l):74-80. McMahon, R. F. 1982. The occurrence and spread of the in- troduced Asiatic freshwater bivalve, Corbicula. fluminea (Muller) in North America: 1924-1981. The Nautilus 96(4):134-141. 1983. Ecology of an invasive pest bivalve, Cor- bicula. IN: The Mollusca, Vol. 6, Ecology, W. D. Russell- Hunter. Ed. Academic Press (New York), pp. 505-561. TROPICAL VERONICELLID, LAEVICAULIS ALTE (FERUSSAC), ESTABLISHED IN SOUTHERN TEXAS Raymond W. Neck Texas Parks and Wildlife Department 4200 Smith School Road Austin, Texas 78744 A number of tropical gastropods have been in- troduced into urban locations in Brownsville, Cameron County, Texas (Neck, 1976). Included are several veronicellid slugs, two of which were reported in an earlier communication (Neck, 1976). An additional species has been observed and was tentatively identified as Pseudoveroni- cella liberiana (Gould) (Neck, 1981). Recently, specimens from this population were sent to Lothar Forcart of Basel, Switzerland, and Jose Willibaldo Thome of Porto Alegre, Brazil, both of whom identified this species as Laevicaulis alte (Ferussac, 1821). Laevicaulis alte was most likely native to cen- 20 THE NAUTILUS January 30, 1985 Vol. 99(1) tral or eastern Africa (Forcart, 1953; in litt.). The type locality of this taxon is Pondicherry, India (Forcart, 1969). Human-mediated disper- sal has allowed this species to establish popula- tions in Madagascar, India, Indonesia, the Philippines, Australia and various island groups in Oceania (Forcart, 1953; Solem 1959, 1964). This southern Texas record apparently repre- sents the first establishment of L. alte in North America. Neither Hanna (1966) nor Dundee (1974) list L. alte, although this species has been established in Hawaii since the 1920's (as Veronicella leydigi (Simroth), in Cockerell, 1925). Summary papers by Baker (1925) and Thome (1975a, b) do not list L. alte for the Americas. First observed in Brownsville in 1975, L. alte has subsequently become the most abundant veronicellid in urban residential yards. Later reports will discuss life history and interactions with other introduced veronicellids. I thank Lothar Forcart and Jose Willibaldo Thome for their prompt identification of the slug. LITERATURE CITED Baker, H. B. 1925. North American Veronieellidae. Proc. Acad. Nat. Sci. Philadelphia 77:157-184. Cockerell, T. D. A. 1925. A visit to the Hawaiian Islands. The Nautilus 38:76-85. Dundee, D. S. 1974. Catalog of introduced molluscs of eastern North America (North of Mexico). Sterkiana 55:1-37. Forcart, L. 1953. The Veronieellidae of Africa (Mollusca, Pulmonata). Ann. Musee Royal Congo Beige. Tervueren, Zool. 23:1-110. 1969. Veronicellid land slugs from the New Hebrides, with description of Semperula solemi. new species. Fieldiana: Zoology 51(12):147-156. Hanna, G. D. 1966. Introduced mollusks of western North America. Occ. Papers California Acad. Sci. 48:1-108. Neck, R. W. 1976. Adventive land snails in the Brownsville, Texas area. Southwestern Naturalist 21:133-135. 1981. Noteworthy gastropod records from Texas. Texas Conchologist 17:69-72. Solem, A. 1959. Systematics and zoogeography of the land and fresh- water Mollusca of the New Hebrides. Fieldiana: Zoology 43:1-238. 1964. New records of New Caledonian non- marine mollusks and an analysis of the introduced mol- lusks. Pacific Science 18:130-137. Thome, J. W. 1975a. Estado atual da sistematica dos veronicelideos americanos (Mollusca, Gastropoda). Arq. Mus. Nac.. Rio de Janeiro 55:155-165. 1975b. Os generos da familia Veronieellidae nas Americas (Mollusca; Gastropoda). Iheringia Zool. 48:3-56. NEW RECORDS OF MARINE MOLLUSCA FROM KHOR ABDULLAH, IRAQ L. A. J. Al-Hassan and Z. I. Al-Hasani Marine Science Centre University of Basrah Basrah, Iraq During the period of November 1982 to November 1983 a number of mollusks were ob- tained from the surface of sediments in Khor Abdullah in the northwest section of the Arabian Gulf. The Khor Abdullah area is situated in a shal- low sea and much of the coastline is bordered by mud and sandy silt (S. A. Darmoian, personal communication). The depth ranges between 5 and 12 meters. The new records include nine gastropods and sixteen bivalves: 1. Euchelis asper (Gmelin, 1791) 2. Turritella terebra (Linnaeus, 1758) 3. Slellaria Solaris (Linnaeus, 1767) 4. Tibia insulaechorab (Roding, 1798) 5. Stromhus decorus persicus (Swainson, 1821) 6. Neuerita didyma (Roding, 1798) V Finis gracilis (Suwerl>\ . 1825) 8. Rapana rapiformis (Born, 1778) 9. Inqui.stor griffithi (Gray, 1834) 10. Siphonaria basseinensis (Melvill, 1893) 11. Anadara antiquata (Linnaeus, 1758) 12. Striarca sculpdlis (Reeve, 1857) 13. Pinna murirnln (Linnaeus, 17fiS) Vol. 99(1) January 30, 1985 THE NAUTILUS 21 14. Pinctada radiata (Leach, 1814) 15. Pteria marmorata (Reeve, 1857) 16. Isogonomon legumen (Gmelin, 1791) 17. Malleus regulus (Forskal, 1775) 18. Placuna placenta (Linnaeus, 1758) 19. Trachycardium. enode (Sowerby, 1840) 20. Gari occidens (Gmelin, 1791) 21. Bassina callophyla (Philippi, 1836) 22. Marcia hiantina (Lamarck, 1818) 23. Paphia gallus (Gmelin, 1791) 24. Periglypta reticulata (Linnaeus, 1758) The only previously published work on the area was by Ahmed (1975) which did not include the newly recorded species under consideration. I wish to thank Dr. R. Tucker Abbott of American Malacologists Inc. for checking the identifications and reviewing the manuscript. I also wish to thank Dr. A. Al-Hashimi of the Kuwait Institute for Scientific Research, Dr. S. A. Darmonian and Dr. S. D. Salman of the Marine Science Centre, University of Basrah, for lending me their specimens. LITERATURE CITED Ahmed, M. M. 1975. Systematic Study on Mollusca from Arabian Gulf and Shatt Al-Arab, Iraq. Centre for Arab Gulf Studies, University of Basrah, Iraq. pp. 78. Allouse, Bashir E. 1956. A Bibliography on the Inverte- brate Fauna of Iraq and Neighbouring Countries. I. Molluscs. Publication no. 8, Iraq Natural History Museum. 32 pp. DISTRIBUTION OF THE SNAIL, MELAMPUS BIDENTATUS, AND THE MUSSEL, GEUKENSIA DEMISSA, ALONG THE PATAGUANSET ESTUARY (CONNECTICUT) IN RELATION TO SALINITY AND OTHER TIDAL MARSH INVERTEBRATES Paul E. Fell and John H. Williams Department of Zoology Connecticut College New London, CT 06320 ABSTRACT A survey was made of the tidal marshes along the Pataguanset Estuary in eastern Connecticut to determine the distributions of Melampus bidentatus Say, Geukensia demissa Dillwyn and a few other invertebrates that are often asso- ciated with these mollusks. Salinity conditions at six stations located along the length of the estuary were examined, and an attempt was made to relate the distri- bution of these animals to salinity. The high marsh species, Melampus bidentatus, Orchestia grillus and Philoscia vittata, and the low marsh fiddler crab, Uca minax, were distributed from the head of the estuary to its mouth. Geukensia demissa and Uca pugnax, which also inhabit the. low marsh, were absent at the head of the estuary where salinity sometimes falls to 0°/00, but they were present in the marshes downstream. Toward the upstream extent of their distributions, the population densities of both Melampus and Geukensia sharply declined. The distributions of these mollusks were consistent with their known salinity tolerances, but it is not yet known to what extent salinity is a determining factor. Although the general community structure of tidal marshes is well-known (Teal, 1962; Day et al, 1973; Nixon and Oviatt, 1973; Subrahman- yam et al, 1976; Fell et al, 1982), relatively little information exists concerning the distribution of tidal marsh invertebrates in relation to salin- ity. Tidal marshes frequently extend far up estuaries, and consequently salinity may be an important factor influencing the occurrence of animals within such marshes. Most of the few 22 THE NAUTILUS January 30, 1985 Vol. 99(1) previous studies on the relationship between salinity and the distribution of tidal marsh in- vertebrates have dealt with only a single or two closely related species (see Daiber, 1977 and 1982 for reviews). Therefore almost no informa- tion is available on how salinity may influence community structure as a whole. A number of studies of tidal marsh mollusks have focused on the high marsh snail, Melampus hitlnita/us Say, or the low marsh mussel, Geu- kensia (formerly in Modiolus) demissa Dillwyn. In general surveys of the Delaware Bay and Chesapeake Bay areas, Melampus (Wass et al, 1972; Leathern and Maurer, 1975; Parker, 1976) and Geukensia (Wass et al, 1972; Maurer et al, 1974) were found to have an upper meso-and polyhaline distribution. Parker (1976) showed that although Melampus occurred in regions which exhibit a wide range of salinity, its popu- lation density was low where salinity was less than about 10°/oo. Kerwin (1972) investigated the distribution of Melampus along an estuary in Virginia; but this snail did not occur in large numbers at any of the sampling stations, sug- gesting that factors other than salinity may be of primary importance in limiting its abundance within that system. The purpose of the current study was two- fold: 1) to examine the salinity conditions at six stations along the length of the Pataguanset Estuary in eastern Connecticut, and 2) to describe the occurrence of Melampus bidentatus and Geukensia demissa in relation to salinity and to the distribution of several other tidal marsh invertebrates. LONG ISLAND SOUND FIG. 1. The Pataguanset Estuary. Tidal marshes are in- dicated by stippling. Salinity sampling stations are designated by their distance in kilometers from the head of the estuary. Invertebrate sampling stations are shown by letters (A to F). E is Watts Island. Study Site; Methods The Pataguanset Estuary is located in eastern Connecticut and opens into Long Island Sound to the west of Niantic Bay from which it is separated by Black Point. The estuary, which is about 3.5 km long, is bordered by tidal marshes and on the south by the large tidal marsh Watts Island (Fig. 1). In most places the depth of the estuary ranges from about 1 to 2 m at high tide. Extensive beds of widgeon grass, Ruppia mari- tima, cover the tidal flats of the lower estuary in the region extending from about 1 to 3 km from the head. Water temperatures along the estuary reach about 25°C during the summer and fall below 0°C during the middle of the winter when much of the estuary may be covered by ice. Six stations were established along the estuary for studying salinity. These were located at 0.5 to 0.7 km intervals from the head of the estuary to a region near its mouth (Fig. 1). During a period extending from late spring through early fall of 1981 and June through August of 1982, surface and bottom salinities at high water of spring tides were determined every 2 weeks. Twice, once in late June and again in late July 1981, salinities were recorded at about hourly intervals covering half of a tidal cycle from low to high tide. Salinities were Vol. 99(1) January 30, 1985 THE NAUTILUS 23 measured in the field with a Goldberg refrae- tometer (American Optical Co.). A few deter- minations of soil water salinities in the high marsh were made after squeezing the water from samples of peat and filtering the water through Whatman no. 1 filter paper. Previous studies on the distribution and abun- dance of Melampus hidentatus on Watts Island in the Pataguanset Estuary and on other Con- necticut tidal marshes have shown that this snail occurs at high densities in areas of the high marsh covered by Spartina patens, stunted Spartitai (litem iflont and .1 uncus gcrardi (Fell et al, 1982 and unpublished observations). For this study it was decided to sample Melampus in S. patens and Juncus because of the abundance of one or both of these plants in marshes along the entire estuary. During the summer of 1981 Melampus was studied at six stations (Fig. 1). The population density of this snail was deter- mined using a 50 cm square wooden frame, 9 cm high, which was tossed onto the marsh in areas of chosen plant cover and at distances of about 2 to 50 m from the water. The vegetation within the frame was clipped at the surface of the peat and all of the snails were collected and enumerated. At the same time the presence of two other high marsh invertebrates, Philnseia vittata (isopod) and Orchestia grillus (amphipod), was noted. The number of quadrats examined at each station is presented in Table 2. The abundance of Melampus, Philoscia and Orchestia at the three stations along the upper estuary was studied in greater detail during the summer of 1982. For this purpose 5 transects running perpendicular to the river bank and situated 15 m apart were set out at each site. Each transect was 25 m long, beginning at the lower edge of the high marsh; and six 50 cm square quadrats placed 5 m apart were exa- mined along each transect. Sampling was done during June, July and August at all three sta- tions. Transect sampling was used to eliminate bias in the selection of sampling sites. The population size of Geukensia demissa was estimated at each of 5 stations during 1981 by counting the number of animals within five 5.5 m transects which extended along the banks of the estuary, except at station E (Watts Island) where the transects were located along a tidal creek. The width of the transects (ca 1 to 2 m) extended from the edge of the water at low tide to the upper edge of the tall Spartina alter- niflora zone. Sampling was done along sections of both banks to assure a representative sample. In addition, the relative abundance of the fiddler crabs, Uca minax and Uca pugnax, was deter- mined in these areas by digging from 50 to about 70 crabs from their burrows at low tide. Salinities There is considerable seasonal variation in salinity at stations in the upper estuary. For ex- ample, the surface salinity at the head of the estuary (St. 0) during high water of spring tides ranged from 0°/oo during early June to more than 20°/oo during late summer of 1981 (Fig. 2). However, at the head of the estuary the surface salinity may drop dramatically whenever there are heavy rains. In mid-September of 1981 the surface salinity at station 0 during high water of a spring tide was only 2°/00 due to fresh water drainage. The range in surface salinities during high water of spring tides narrowed toward the mouth of the estuary, and at 1.8 km down- stream the range was only 24 to 32°/00 over the period of observation. During the summer of 1982, surface salinities at the 3 stations of the upper estuary during high water of spring tides exhibited patterns similar to those of 1981, but they were often 5 to 10°/oo lower for any par- ticular time. Salinities recorded at different times during the tidal cycle also exhibited substantial changes 35 30- ^25- Q. Q. ~ 20 - > 1 15 < *" 10 — I 5 0 FIG. 2. Surface salinities at four stations along the upper Pataguanset Estuary during high water of spring tides in 1981. The stations are designated by their distance in kilometers from the head of the estuary. 24 THE NAUTILUS January 30, 1985 Vol. 99(1) at stations in the middle and upper regions of the estuary (Fig. 3). At the station 1.1 km from the head of the estuary, the surface salinity ranged from 3°/oo at low water to 20°/oo at high water during neap tides in late June and late July of 1981. As would be expected, the surface salinities at the head of the estuary were fre- quently much greater during high water of spring tides than during the same period of neap tides (Figs. 3 and 4). Often the salinity at the surface and that at the bottom were identical or very similar; however, occasionally stratifica- tion was noted at the stations of the upper estuary. The difference between surface and bottom salinities at any given station usually did not exceed 10o/oo and was greatest during high tide. However, when a perigee spring tide oc- curred during a period of heavy rain (16 Sept. 1981), the surface salinity at the head of the estuary was 2°/oo at high water while the bottom salinity was 25°/00. On two occasions the salinity of the water actually flooding the high marsh of the upper estuary was measured and found to be about the same as the surface salinity in the channel. How- ever, the salinity of the water just above the peat was somewhat different. For example, once when station A was flooded to a depth of about 20 cm the salinity at the surface was 2°/00, as it also was in the channel, but close to the peat the salinity was 5 to 7°/00. In late June and again in late July of 1981 the salinity of the soil water of the high marsh was measured at stations in the upper estuary dur- ing low tide. The soil water had a salinity of 7 to 16°/00 near the head of the estuary and exhibited progressively high salinities at stations toward the mouth (Table 1). Animal Distribution Melarrvpus bidentatus was found at all stations along the estuary (Table 2). However, it was less abundant in the brackish marshes near the head of the estuary than in the marshes toward the mouth. Another pulmonate snail, Succirwa wilsoni Lea, which is typically found in fresh- 35 - 30 25- «»■ 20 Q. t ,5" z 10 - 5 0- • A -I HOURS FIG. 3. Surface salinities at six stations along the Pataguanset Estuary during the flooding phase of the tidal cycle. The stations are designated by their distance in kilometers from the head of the estuary. Solid circles joined by continuous lines show salinities during part of a neap tidal cycle on 22 July 1981; open triangles indicate the low tide and high tide values during a neap tide on 23 June 1981 ; and open circles joined by broken lines show salinities at station 0 on 5 August 1981. LT = low tide. Vol. 99(1) January 30, 1985 THE NAUTILUS 25 50 JO 20 A 1981 N = 40 B 1981 n 917 C 1981 N: 277! -I — I — I — I — 1 Z 50 30 2 0 A 1982 N 4.' B 19 8 2 . N .- 2 5 3 5 7 II 13 — i — l — l — i — i — i — i — | — i — i — i 3 5 7 9 11 13 SHELL LENGTH (mm) C 1982 _ n: 1231 7 9 II 13 FIG. 4. Size frequency distribution of Melampus bidentatus at 3 stations along the upper Pataguanset Estuary during 1981 and 1982. TABLE 1. Soil water salinities at stations in the upper Pataguanset Estuary during periods of neap tides. Salinity ("/„„) r.isi Station 6/23 7/22 A 7-11 11-16 B 13-16 20-25 C - 32 water marshes, occurred together with Melam- pus at stations A and B. The vegetation in the higher regions of these brackish marshes con- sisted of Juncus gerardi and Spartina patens mixed with Solidago sempervirens, Potentilla anserina, Gerardia maritima, Panicum virga- tum and other species. Downstream the num- bers of Melampus increased until at 1 km or more from the head high densities of this snail were found in relatively pure stands of Juncus gerardi and of Spartina patens. Two inverte- brates that are normally associated with Melam- pus in salt water marshes, Philoscia vittata and Orchestia grillus, (Fell et al, 1982) were also distributed all along the Pataguanset Estuary, including the brackish marshes at its head (Table 2). Although the surveys of 1981 and 1982 were in agreement in showing a progressive decline in the population density of Melampus in the marshes of the upper estuary, the density of this snail at particular stations was much lower dur- ing the second summer (Table 3). In addition, during 1982 there was also a marked reduction in the proportion of smaller individuals (Fig. 4). It is not known whether these changes were related to the lower salinities occurring during 1982 or to other factors such as high winter mortality. Geukensia demissa did not occur at the head of the estuary. Only a few small mussels were observed 0.5 km below this point, but at 1 km or more from the head these animals were moder- ately abundant (Table 3). Fiddler crabs often occur together with Geukensia in the low marsh. Two species of fiddler crab, Uca minax and Uca pugnax, were found; and one or both species were present at stations all along the Pataguan- set Estuary. Only Uca minax occurred at the head of the estuary and this species was the dominant fiddler crab at the station 0.5 km downstream. However, at all of the lower sta- tions Uca pugnax predominated. The distribu- tion of this fiddler crab was essentially the same as that of Geukensia. 26 THE NAUTILUS January 30, 1985 Vol. 99(1) TABLE 2. Abundance, no. per0.25mJ (mean ± S.D.. range), of high marsh invertebrates along the Pataguanset Estuary in Connecticut. N = no. of quadrats examined. Mi In lupus liiilcnlntiis Phil N osda vittata 1982 Orrh N ■stm grillus Station N r.'Mi N 1981 N 1982 1982 A 10 4 + 5.0-15 30 1 + 5,0-24 30 3 ±3,0-8 30 3±3,0-10 B 20 40 + 31,4-134 30 8 ±10.0-43 30 7+ 11,0-56 30 5 ±5,0-24 C 15 184 + 99,14-336 30 41 + 35,0-146 30 6 + 6,0-31 30 4.5±4,0-16 D 5 222 + 53,163-284 E 36 92 + 81.0-312 15 79 ±75,6-306 F 14 112 ±83,2-263 TABLE 3. Distribution of low marsh invertebrates along the Pataguanset Estuary in Connecticut during the summer of 1981 (number of Geukensia per 5x 5.5m transects). Station Geukensia demissa I'm ■pugnax: Uca minax A 0 0;64 B 3 9:45 C 196 43:7 D 410 :'.1:1 E 143 65:4 Discussion Geukensia demissa was moderately abundant in the lower portions of the Pataguanset Estuary where the salinity of the water at high tide probably only rarely drops much below 10°/oo. On the other hand, it was absent from the marsh at the head of the estuary and was pre- sent in only small numbers 0.5 km downstream. At these stations the surface salinities at high tide were sometimes as low as 0 to 2°/00. Uca pugnax had a similar distribution, but Uca minax was abundant at stations along the banks of the upper estuary. Geukensia can survive and remain active at salinities as low as 8°/00, but evidently is unable to tolerate prolonged sub- mergence by water of salinities below about 5°/00 (Wells, 1961; Lent, 1969; Pierce, 1970; Maurer et al, 1974). Similarly, Teal (1958) has shown that Uca pugnax is less tolerant of low salinity than is Uca minax, succumbing within a few days if submerged in water with a salinity of 7°/0o or lower (LD50 =1.5 days at 0°/oo and 3 days at 7"/00). Eurthermore, when given a choice be- tween fresh water and 30°/oo sea water, Uca pugnax usually chose sea water while lira minax usually chose fresh water. The predominance of Uca minax in regions of low salinity and of Uca pugnax in regions of high salinity has been observed in a number of marsh systems (Teal, 1958; Kerwin, 1971; Miller and Maurer, 1973). Competition between these 2 species of fiddler crabs, as well as other factors, undoubtedly also influence their distribution (Teal, 1958; Miller and Maurer, 1973; Daiber, 1977). The fact that Geukensia demissa and Uca pugnax have similar salinity tolerances and exhibit essentially the same distribution along the estuary lends strength to the hypothesis that salinity may be an important factor determining their distribu- tion within this system. Melampus bidentatus was found all along the Pataguanset Estuary, as were Orchestia grillus and Philoscia vittata. The high marsh is basical- ly a terrestrial environment most of the time, but it is regularly flooded by spring tides. Conse- quently, the salinity of the estuarine waters could be expected to exert less of an influence on the distribution of animals inhabiting this region than on those of the low marsh which is inun- dated more often and for longer periods. On the other hand, the density of Melampus was lower in the brackish marshes of the upper estuary and this may be related, at least in part, to the lower salinity of the soil water and/or more probably of the waters of inundation. Not only may low salinity have a direct influence on the snails but it may also act indirectly through its effects on the vegetation which is different in the brackish marsh. The observations of Parker (1976) further support this suggestion. In a study of 12 sites along the New Jersey and Delaware sides of Delaware Bay and 4 stations along the Broadkill River in Delaware, he also found that Melampus occurs in brackish marshes but that its population density is low where the salinity is less than about 10°/oo. Along a tributary of the York River in Virginia, Melampus was absent from marshes in regions where the mean surface salinity was below 4°/oo Vol. 99(1) January 30, 1985 THE NAUTILUS 27 and was present in only small numbers in marshes located toward the mouth (Kerwin, 1971 and 1972). In this system it appears that other factors besides salinity may be of major importance in limiting snail density. Melampus adults are remarkably tolerant of submergence in water ranging in salinity from full strength sea water to fresh water. They were found to survive total submergence in fresh water for a least one day at 20 °C and for at least 8 days at 10°C (Price, 1980; McMahon and Russell-Hunter, 1981). Melampus possesses a planktonic larva (Russell-Hunter, Apley and Hunter, 1972) which is also tolerant of low salinities (Parker, 1976). The larvae are highly active at salinities ranging from 15 to 40o/oo, slightly less active at 10°/oo and much less active at 5°/00. About 90% of 2-day-old larvae were observed to survive for at least 10 hrs. in salinities ranging from 2.5 to 40°/oo, but none survived that long in fresh water (Parker, 1976). Although the distributions of Melampus biden- tatus and Geukensia demissa along the Pataguanset Estuary are consistent with the salinity tolerances of these animals determined by laboratory experiments, it is not yet known whether salinity is, in fact, a major factor deter- mining the distribution and abundance of these animals. Among other factors that may be im- portant are predation, composition of the sub- stratum and flooding regime. Future studies should focus on more precisely defining the con- ditions which actually exist in various regions of the marsh system and on how these conditions affect all stages of the life history of the animals which live there. This will require that field measurements be made at frequent intervals, if not continuously, throughout the year and that field studies be accompanied by extensive laboratory experiments. In most laboratory studies, the effects of continuous exposure to a particular set of conditions are examined. However, in the marsh flooding is periodic, and therefore it would be desirable to look at the ef- fects of submersion by water of different salinities under regimes comparable to those that would be experienced by animals in the field. Until such comprehensive studies have been carried out, it will not be possible to make really meaningful statements concerning the causative factors which result in the observed distributional patterns. Acknowledgments Appreciation is expressed to Mary Ann Tilton, Elizabeth Brown, Mark Pereira, Kenneth Cadigan, Richard Orsen and Nanette Brodeur for assistance with the field work and to Dr. Dorothea Franzen for identifying Succinea wilsoni. This study was supported by grants from the Andrew Mellon and Seth Sprague Foundations. LITERATURE CITED Daiber. F. C. 1977. Salt-marsh animals: distribution related to tidal flooding, salinity and vegetation. In. V. J. Chap- man, ed., Ecosystems of the World 1. Wet Coastal Ecosys- tems. Elsevier Sei. Publ. Co., Amsterdam, Oxford, New York, pp. 79-108. 1982. Animals of the Tidal Marsh. Van Nostrand/Reinhold Co., New York, 422 pp. Day, J. W. Jr., W. G. Smith, P. R. Wagner and W. C. Stowe. 1973. Community structure and carbon budget of a salt marsh and shallow bay estuarine system in Louisiana. Publ. No. LSU-5G-72-04, 77 pp. Fell, P. E., N. C. Olmstead, E. Carlson, W. Jacob, D. Hitchcock and G. Silber. 1982. Distribution and abundance of macroinvertebrates on certain Connecticut tidal marshes, with an emphasis on dominant molluscs. Estuaries 5:234-239. Kerwin, J. A. 1971. Distribution of the fiddler crab (Uca minax) in relation to marsh plants within a Virginia estuary. Chesapeake Set. 12:180-183. 1972. Distribution of the salt marsh snail (Melampus bidentatus Say) in relation to marsh plants in the Poropotank River Area, Virginia. Chesapeake Sci. 13:150-153. Leathern, W. and D. Maurer. 1975. The distribution and ecology of common marine and estuarine gastropods in the Delaware Bay area. The Nautilus 89:73-79. Lent, C. M. 1969. Adaptations of the ribbed mussel, Modio- lus demissus (Dillwyn), to the intertidal habitat. Amer. Zool. 9:283-292. Maurer, D.. L. Watling and G. April. 1974. The distribution and ecology of common marine and estuarine pelecypods in the Delaware Bay area. The Nautilus 88:38-45. McMahon, R. F. and W. D. Russell-Hunter. 1981. The effects of physical variables and acclimation on survival and oxygen consumption in the high littoral salt-marsh snail, Malampus bidentatus Say. Biol. Bull. 161:246-269. Miller, K. G. and D. Maurer. 1973. Distribution of the fiddler crabs, Uea pugnax and Uca minax, in relation to salinity in Delaware rivers. Chesapeake Sci. 14:219-221. Nixon, S. W. and C. A. Oviatt, 1973. Ecology of a New- England salt marsh. Ecol. Monogr. 43:463-498. Parker, N. H. 1976. The distribution, growth and life history of Malampus bidentatus (Gastropoda: Pulmonata) in the Delaware Bay region. Master's Thesis. Univ. Delaware. 65 pp. 28 THE NAUTILUS January 30, 1985 Vol. 99(1) Pierce, S. K. ,Ir. 19T0. The water balance of Modiolus (Mollusca: Bivalvia: Mytilidae): osmotic concentrations in changing salinities. Comp. Biochem. Physiol. 36:521-533. Price, C. H. 1980. Water relations and physiological ecology of the salt marsh snail, Melampus bidentatus Say. Jour. Exp. Mar. Biol. Ecol. 45:51-68. Russell-Hunter, W. D., M. L. Apley and R. D. Hunter. 1972. Early life-history of Melampus and the significance of semilunar synchrony. Biol. Bull. 143:623-656. Subrahmanyam, C. B., W. L. Krucznski and S. H. Drake. 1976. Studies on the animal communities in two north Florida salt marshes part II. macroinvertebrate com- munities. Bull. Mar. Sci. 26:172-195. Teal, J. M. 1958. Distribution of fiddler crabs in Georgia salt marshes. Ecology 39:185-193. 1962. Energy flow in the salt marsh ecosystem in Georgia. Ecology 43:614-624. Wass, M. L. et al. 1972. A check list of the biota of the lower Chesapeake Bay. Spec. Sci. Rep. No. 65 Virginia Inst. Mar. Sci. pp. 1-290. Wells, H. W. 1961. The fauna of oyster beds with special reference to the salinity factor. Ecol. Monogr. 31:239-266. TWO NEW SPECIES OF LYRIA FROM THE WESTERN ATLANTIC (GASTROPODA: VOLUTIDAE) William K. Emerson Department of Invertebrates American Museum of Natural History New York, New York 10024 ABSTRACT Lyria leonardi n. sp. and Lyria russjenseni n. sp. are described from recently collected specimens obtained in moderate depths off southwestern Puerto Rico. The former species is also known from the Gulf of Triste, Venezuela, and off Grenada in the Lesser Antilles on the basis of fragmental specimens. Both taxa are compared with extant and extinct species q/*Lyria occurring in the Caribbean region. The volutid genus Lyria (sensu stricto) is represented in the Tertiary of the western Atlantic region by eight extinct species (Hoerle and Vokes, 1978) and by six extant species, in- cluding the two new taxa described herein (Weaver and duPont, 1970; Bayer, 1971). I take pleasure in naming the new species in honor of Fred L. Leonard and Russell H. Jensen, who kindly called my attention to specimens of these taxa and generously donated their respective specimens to the American Museum of Natural History (AMNH) type collection. The previously known western Atlantic Recent species that have been referred to the nominate subgenus are: 1. Lyria beauii (Fischer and Bernardi, 1857), pi. 9, figs. 1, 2; Dance, 1969, pi. 16, fig. c; Weaver and duPont, 1970, pi. 4, figs. I, J; Pointier, 1981, pi. 1, figs. 1-4; and Abbott and Dance, 1982, p. 213, Type locality: Marie- Galante, Lesser Antilles. Known only from a few specimens taken in the Lesser Antilles, most recently from off Guadeloupe Island. 2. Lyria archeri (Angas, 1865), p. 55, pi. 2, figs. 4, 5; Weaver and duPont, 1970, pi. 7, figs. G, H; Abbott, 1974, p. 245, fig. 2675 (not L. beauii); Pointier, 1981, pi. 2, figs. 6-14; Abbott and Dance, 1982, p. 213. Type locality: Montser- rat, Lesser Antilles, recently obtained off Marti- nique (AMNH coll. 183213). R. T. Abbott re- ports (in lit.) that Lesley Sutty collected speci- mens in Guadeloupe in 1969. Dall (1907, p. 351) referred this species to the genus-group taxon Enaeta H. & A. Adams (1853, vol. 1, p. 167) in the mistaken belief that the outer lip had similar labial dentition. In Enaeta. a blunt, tooth-like projection occurs near the midpoint of the outer lip near the margin of the labrum, (Hoerle and Vokes, 1978, p. 115). In Lyria archeri, the edge of the labrum is weakly serrated and pustule- like denticles form at the marginal base of some of the serrations inside the outer lip. These Vol. 99(1) January 30, 1985 THE NAUTILUS 29 "teeth" are prominent in the holotype (Weaver and duPont, 1970, pi. 7, fig. H). As Try on (1882, p. 104) pointed out, however, the shell of Lyria archeri somewhat resembles that of the Indo- Pacific Lyria (L.) ynitraeformis (Lamarck, 1811). This species apparently is not closely allied to the other living Lyria in the Caribbean region. 3. Lyria vegai Clench and Turner, 1967, fig. 1; Weaver and duPont, 1970, pi. 6, figs. F, G; Abbott, 1974, p. 245, fig. 2676; Pointier, 1981, pi. 1, fig. 5; Abbott and Dance, 1982, p. 214 (holotype illus.). Type locality: "Cabo Rojo, Prov. Pedernales, Repiiblica Dominicana, Hispaniola", in a fish trap. Known only from the holotype. 4. Lyria cordis Bayer, 1971, figs. 58 (shell), 59 (living animal), 60 (radula), 61 (a, gross anatomy; b, operculum); Abbott, 1972, p. 139 (living animal), Abbott, 1974, p. 245, fig. 2677; Pointier, 1981, pi. 1, fig. 6; Abbott and Dance, 1982, p. 214 (holotype). Type locality: "Carib- bean Sea, 20 miles ESE of Sto. Domingo, Island of Hispaniola, 18° 21.0' N, 69° 14.3' W, depth 174 m." Known only from 2 specimens from the type locality. This is the type species of the genus-group taxon, Cordilyria Bayer (1971, p. 204). Notwithstanding the fact that axial sculp- ture occurs only on the first and second post nuclear whorls in the type species (L. cordis) as well as in Lyria vegai, and axial costae are prominent on the body whorl and the earlier whorls of Lyria beauii, L. russjenseni n. sp. and L. leonardi n. sp., these five species appear to be more closely related to each other than to Lyria archeri. They form a species complex for which the subgenus Cordilyria is available, if recogni- tion is subsequently deemed warranted on the basis of anatomical differences with the Indo- Pacific Lyria. For the present, Lyria archeri seems best retained in Lyria (sensu stricto). The New World representatives of the Cordi- lyria species complex occur in moderately deep water in the Caribbean Sea and are rarely found in collections. All the specimens I have exa- mined of the two species described here were dead-collected. Most appear to have been oc- cupied by hermit crabs, which would account for the presence of these shells in baited fish traps. The shells possess one or more octopus drill holes, suggesting that the specimens were the victims of octopod predation. Family Volutidae Rafinesque, 1815 Subfamily Lyriinae Pilsbry and Olsson, 1954 Genus Lyria Gray, 1847 Lyria Gray, 1847, p. 141; type species by original designation: Voluta nucleus Lamarck, 1811, Recent, Indo-Pacific. Lyria leonardi new species Figures 1 to 6 Lyria beauii Fischer and Bernardi, Dall, 1907, p. 351, fragmental specimen, National Museum of Natural History (NMNH) 87718, near Grenada, in 133.5 m. Not Lyria beauii (Fischer and Bernardi, 1857). Lyria cf. limata Hoerle and Vokes, Petuch, 1981, p. 331, figs. 75, 76, Golfo de Triste, Vene- zuela, in 16 m. Not Lyria (L.) limata Hoerle and Vokes, 1978, p. Ill, pi. 1, figs. 4, 5, Chipola For- mation, Florida, Miocene. Diagnosis: Ovately fusiform shell, large for genus, attaining 100 + (?) mm in length, of 8V2 whorls; axial sculpture of 11 to 14 weakly folded ribs; color tannish white; spirally banded by ir- regular squarish blocks of brown below the suture and with 3 similar spiral bands on the body whorl; spirally threaded by 6 to 7 brown, strongly penciled lines on the body whorl, with 1 to 3 similar spiral lines on the earlier post nuclear whorls; aperture whitish with yellowish buff submarginal callus within the outer lip. Description: Shell ovately fusiform; 2V2 smooth nuclear whorls; 6 post nuclear whorls; first 3 post nuclear whorls with 14 well-defined axial costae (see Fig. 3); remaining post nuclear whorls with 11 loosely formed axial ribs; suture weakly defined; aperture elliptical, more than V2 the height of the shell; outer lip lacking marginal barbs, thickened internally by a submarginal lenticular callus; columella with 3 prominent adapical plications and 9 thread-like lirations, with the most adapically placed lira best developed; siphonal fasciole weak, anal sulcus shallow; operculum and radula unknown. Color, see diagnosis. Type locality: off Cabo Rojo, Puerto Rico, trawled in 500 ± m., ex-E. Flynn Ford coll., ex- Fred L. Leonard coll., 1981. Holotype: AMNH no. 213575, from the type locality; height = 52 mm, width = 21.2 mm. Here illustrated, Figs. 1, 2 and 3. Paratype: NMNH no. 820640, R/V John 30 THE NAUTILUS January 30, 1985 Vol. 99(1) FIGS. 1-6. Lyria leonardi new species. 1-3, Holotype, AMNH no. 213575; 4-6, Paratype, NMNH no. 820640. 1 and 2 approx- imately x lVs; 3, early whorls greatly enlarged; 4-6, x 1. Vol. 99(1) January 30, 1985 THE NAUTILUS 31 Elliott Pillsbury station P-758 (11° 42.4' N., 60° 40' W), in 16 m., Golfo de Triste, Venezuela (see Petuch, 1981, p. 331, figs. 75-76); fragment lacking pre-body whorls, height = 72.00 mm. Here illustrated, Figs. 4-6. Referred specimen: NMNH no. 87718, U.S. Fish Commission station 2120, in 133.5 m, near Grenada, Lesser Antilles (see Dall, 1907, p. 351); fragment lacking much of the body whorl, height = 29.3 mm. Remarks: The color pattern approaches that of L. limata Hoerle and Vokes (1978, pi. 1, figs. 5a, 5b), but this smaller, more slender Miocene species has better developed costae, stronger and fewer columellar lirations, and possesses barbs on the outer lip. Lyria russjenseni new species Figures 7 to 15 Diagnosis: Shell narrowly fusiform, 8V2 whorls, medium size for genus, attaining 70 + mm in height; axial sculpture of 12 to 13 ir- regularly formed ribs; color buff-cream with small v-markings, spirally banded by broken blotches of irregular brown squares below the suture, midway and anteriorly on the body whorl; bands interrupted by zigzag patterns, especially at base of the body whorl; outer lip ringed within by a yellowish buff, submarginal callus; aperture white. Description: Shell slender, fusiform; 2V2 smooth nuclear whorls; 6 post nuclear whorls; axial costae 12 to 13 per whorl, weakly devel- oped on 1st and 2nd post nuclear whorls (see Fig. 15); obsolete on 3rd and 4th whorls; promi- nent on penultimate whorl and body whorl; suture distinct, weakly channeled; aperture nar- rowly elongate, about V2 the height of the shell; interior of outer lip thickened submarginally by a lenticular callus in mature specimens, lacking marginal barbs; columella with 3 prominent adapical plications and 12 to 17 weak lirations extending into the aperture, terminating in a more prominent lira at the adapical end in mature specimens. Siphonal fasciole weak; anal sulcus narrow and shallow; operculum and radula unknown. Color, see diagnosis. Type locality: off La Paguera, Puerto Rico, taken in a lobster pot by fisherman, 1978, ex- Miguel Carlo, ex-Russell Jensen coll. Holotype: AMNH no. 213576, from the type locality; height = 65.5 mm, width = 26.2 mm. Here illustrated, Figs. 7, 8. Paratype A: off Cabo Rojo, Puerto Rico, in a fish trap, in approximately 244 m., ex-Miguel Carlo, 1983, Harry G. Lee coll.; height = 71.5 mm, width = 28.8 mm. Here illustrated, Figs. 9, 10, and 15. Paratype B: off Cabo Rojo, Puerto Rico, in a fish trap set 8 to 10 miles off shore in approxi- mately 300 m., mid-1979, ex-Miguel Carlo, Gregory Curry Sr. coll.; height = 39.4 mm, width = 17.2 mm. Paratype C: AMNH no. 213574, same locality as paratype B, ex-Miguel Carlo, 1979, ex- Richard Goldberg coll.; height = 26.8 mm, width = 13.4 mm. Juvenile specimen, here il- lustrated, Figs. 13, 14. Paratype D: same locality as paratype B, ex- Miguel Carlo; Gregory Curry, Sr. coll.; height = 57.7 mm (apex incomplete), width = 25.4 mm. Here illustrated, Figs. 11, 12. Paratype E: off Mayaquez, Puerto Rico, in a fish trap, set in 274 mm; ex-Miguel Carlo, 1982, Michael Cahill coll.; height = 56 mm, width = 24 mm. Remarks: This species resembles L. beauii (Fischer and Bernardi, 1857) in shell morphol- ogy, but it differs in having less extended axial ribs on the body whorl, and a distinctive color pattern. In Lyria leonardi n. sp. the axial ribs adjoin the suture, whereas in the present species and L. beauii the ribs are poorly developed at the suture in mature specimens (Figs. 7-10). Acknowledgments In addition to Russell H. Jensen and Fred L. Leonard, I am indebted to a number of people for valuable contributions to this study. The fol- lowing generously provided specimens on loan and/or contributed pertinent information: Kirk Anders, Michael Cahill, Miguel Carlo, Gregory Curry, Sr., C. John Finlay, Mary S. Ford, Richard Goldberg, Thomas Honker, Harry G. Lee, Edward J. Petuch, Joseph Rosewater, John K. Tucker, and Thomas R. Waller. My AMNH colleagues, Walter Sage, III, Peter J. Harries, and Stephanie Crooms kindly provided technical assistance, photography, and the word processing, respectively. 32 THE NAUTILUS January 30, 1985 Vol. 99(1) FIGS. 7-l.r>. Lyria russjenseni nnr spears. 7 and 8, Holotype, AMNH no. 213576; 9, 10, 15, Paratype A, H. G. Lee coll.; 11 and 12, Paratype D, G. Curry, Sr. coll.; 13 and 14, Paratype C. AMNH no. 213574. 7-14 approximately x IVs; 15, early whorls greatly enlarged. Vol. 99(1) January 30, 1985 THE NAUTILUS 33 LITERATURE CITED Abbott, R. T. 1972. Kingdom of the Seashell, New York, 256 pp. 1974. American Seashells, The Marine Mollusea of the Atlantic and Pacific Coasts of North America, New York, 2nd ed., 663 pp., 24 pis., text figs. Abbott, R. T. and Dance, S. P. 1982. Compendium of Sea- shells, A Color Guide To More Than 4,200 of the World's Marine Shells, New York, 411 pp., illus. Adams, H. and A. 1853[-1854]. The Genera of Recent Mol- lusea; arranged according to their organization. London, vol. 1, pp. 1-256, pis. 1-32 [1853]; pp. 257-484, pis. 33-60 [1854]. Angas, G. F. 1865. Descriptions of ten new species of shells, chiefly from the Australian Seas, Proc. Zool. Soc. London, pt. 1, pp. 55-58, pi. 2. Bayer, F. M. 1971. Biological results of the University of Miami Deep-Sea Expeditions. 79. New and unusual mol- lusks collected by R/V John Elliott Pillsbury and R/V Gerda in the tropical western Atlantic. Bull. Mar. Set., vol. 21, no. 1, pp. 111-236, 72 figs. Clench, W. J. and Turner, R. D. 1967. A new species of Lyria (Volutidae) from Hispaniola. The Nautilus, vol. 80, no. 3, pp. 83-84, figs. 1-3. Dall, W. H. 1907. A review of the American Volutidae. Smithsonian Misc. Coll., vol. 48, no. 3, pp. 341-373. Dance, S. P. 1969. Rare Shells. Berkeley, 128 pp., 25 pis. Fischer, P. and Bernardi, A. C. 1857. Descriptions d'especes nouvelles. Jour. ConchyL, vol. 5, no. 3. pp. 292-300, pis. 8, 9. Hoerle, S. E. and Vokes, E. H. 1978. A review of the volutid genera Lyria and Falsilyria (Mollusea: Gastro- poda) in the Tertiary of the Western Atlantic. Tulane Studies Geol. and Paleont, vol. 14, no. 3, pp. 105-130, pis. 1-5. Petuch, E. J. 1981. A relict Neogene caenogastropod fauna from northern South America. Malacologia, vol. 20, no. 2, pp. 307-347, figs. 1-130. Pilsbry, H. A. and Olsson, A. A. 1954. Systems of the Voluti- dae. Bull. Amer. Paleont., vol. 35. no. 154, pp. 1-37, pis. 1-4. Pointier, J. P. 1981. Les Lyria des Caraibes. Xenophora (Bull. Club Francais Collectionneurs de Coquillages), no. 3, May, pp. 13-15, 4 text figs., 2 pis. Tryon, G. W., Jr. 1882. Family Volutidae, Manual of Conchology, ser. 1, vol. 4, pp. 73-105, pis. 22-31, Phila- delphia. Weaver, C. S. and duPont, J. E. 1970. The Living Volutes, A Monograph of the Recent Volutidae of the World. Delaware Mus. Nat. Hist. Monogr. Ser. no. 1, 375 pp., 78 pis.-, 43 text figs. Collectible Shells of Southeastern U.S., Bahamas & Caribbean by R. Tucker Abbott, Ph.D A Take it to the Beach' Field Guide WATERPROOF - TEARPROOF 105 beautiful color photos of living animals and their shells 64 pages of color 300 species il- lustrated. How to clean shells. Where to find them Includes fossils, pond and tree snails, as well as seahfe. Collectible Shells stresses conservation, but also has helpful hints about collecting and cleaning shells The book introduces the tourist and beginner to famous Florida fossils and the unique world of tree and pond mollusks Printed on a washable, tearproof plastic 'paper ' Drop it in the ocean, use it in the rain, or let your wet shells drip all over it. Keep it on your boat or take it to the shore A popular new seller retailing for $8 95 Postage and state tax are included as a big savings American Malacologists, Inc. Publishers of Distinctive Books on Mollusks P.O. 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CLOVER nmi east of Port Canaveral, Florida, 73 m; FSBC 1 31761; dorsal girdle scales i ■ 515); 8. same; ven tral girdle scales ( x 550). coordinates; 77.7 m; 21 September 1976; IRCZM 61:061. - 4 paratypes, 1.5-8.5 mm; JSL Station 2160A; same coordinates; 73.8 m; 2 February 1977; IRCZM 61:062.- 1 paratype, 7.0 mm; JSL Station 2163A; same coordinates; 80 m; 7 February 1977; IRCZM 61:063.- 1 paratype, 1.8 mm; JSL Station 2163B; same coordinates, depth, and date; IRCZM 61:064.- 1 paratype, 16.0 mm; [?] 28°02'N, 80°26'W, 8 nmi east of Grant; is m; 6 June 1978; BMI 1143.- 2 paratypes, 9.0, 10.0 mm; 28°02.8'N, 79 r.s.o'W. 31.5 nmi SF of Port Canaveral; 73 m; 22 May 1973; ANSP A-10629.- 1 paratype, 12.0 mm; 28°10'N, 80°03'W, 30 nmi ENE of Melbourne; 53 m; September 1981; AMNH 70. - 2 paratypes, 6.5, 16.0 mm; 28°18.9'N, 79 9 I'W, 23.5 nmi east of Port Canaveral; 73 m; 19 June 1973; FSBC I 31761.- 1 paratype, 13.5 mm; 28°35'N, 80°07'W, 24 nmi ENE of Cape Canaveral; 61 m; July 1982; BM(NH) 1985007.- 1 paratype, 9.5 mm; 28°37.1'N, 80°04.8'W, 25 nmi FNF of Cape Canaveral: 64 m; 14 August 1973; CAS 056545.- 1 paratype, 18.0 mm; 28°41'-40'N, 80°03'W, 28 mi ENE of Cape Canaveral; 86-91 m; 23 April 1983; FSB< ' I 30775.- 1 paratype, 13.0 mm; 30 00'N, 80°15'W. 54 nmi FNF of St. Augustine; 73.1-82.2 m; 24 June 1982; FSBC I 30774. NORTH CAROLINA: 1 paratype. 14.5 nun; Eastward Station 480; 34'12'N, 76' 05.9'W, SE ,>( Cape Lockout; 73-107 m; 18 March 1969; UNC 4302.1- GRAND BAHAMA ISLAND: 1 tail valve (viii). 7.3 nun wide. 4.2 mm long; Gold Rock; 24.1 m; J. N. Worsfold, coll.; July 1981; Vol. 99(2-3) April 29, 1985 THE NAUTILUS 37 FSBC I 31762. - 1 tail valve (viii), 7.0 mm wide, 3.8 mm long; Tamarind Beach Reef; 46.8 m; Worsfold collection. - 1 intermediate valve, 7.2 mm wide, 3.1 mm long at jugum; Gold Rock; 26.2 m; Worsfold collection.- 1 intermediate valve, 9.9 mm wide, 4.5 mm long at jugum; Indian Cay; 23.0 m; Worsfold collection. Description: Largest entire specimen 21.0 mm long, 9.5 mm wide, including girdle. Some paratypes bright orange; holotype and other paratypes yellow or beige with white stripe on jugum; stripe sometimes overlain with orange, anteriorly directed, slender triangle; or, in addi- tion, with dark brown in central areas of valves ii, iv, v, vii, and viii. Tegmentum ornamented with rounded, large pustules (to 300 \xm dia- meter) and linearly aligned, usually small (to 150 \xm diameter) pustules. Width of tegmentum of valves of undissected holotype: i = 3 . 6 ; ii = 4.1; iii = 4.5; iv=4.6; v=4.8; vi = 4.9; vii = 4.5; viii = 3.6 mm. Head valve (i) ornamentation beginning as radial rows of 3 or 4 small pustules at apex, thereafter losing alignment but closely situated, increasing in size toward margin, resulting in vaguely concentric arcs of pustules of similar size. Lateral areas of intermediate valves (ii-vii) with about 30-50 large pustules, seldom if ever connected, those at anterior margins aligned in transverse rows, others scattered, all closely packed, increasing in size toward anterolateral corners; central areas with as many as 19 or 20 subparallel, occasionally converging, longitu- dinal rows of small pustules (8-9 rows on holo- type); pustules of rows increasing in size and decreasing in numbers toward lateral margins; as many as 20 small pustules in rows near jugum; rows usually continuing over jugum of valves ii and vii, sometimes absent or inter- rupted at jugum of valves iii-vi; posterior edges of intermediate valves straight in larger speci- mens, slightly beaked in smaller specimens, all slightly peaked (subcarinate) at center. Tail valve (viii) with mucro slightly elevated, a little anterior of center, thereafter dropping away concavely for a short distance and then sloping gently to posterior margin; jugum and central areas with parallel rows of small pustules; re- mainder of valve with large, densely packed pustules arranged in concentric rows of pustules of similar size, largest at margin. Articulamentum white, with light brown or orange hues evident through strongly excavate surfaces beneath lateral areas, somewhat less evident beneath central areas, occasionally with an orange, longitudinal stripe beneath jugum. Insertion teeth well defined, relatively sharp, thickened near slit; slit formula 11-1-8. Sutural laminae relatively short, broadly rounded ante- riorly; sinus well defined; on valve viii of 16.0 mm specimen, width of sinus 0.9 mm, width of sutural laminae 2.4 mm; ratio (relative width of sinus) 0.375. Eaves solid. Girdle upper surface paved with small (about 70-75 x 20-35 ^m), ovoid, elongate scales, coarse- ly striated toward sometimes pointed distal tips, interspersed with a few glassy spicules up to 350 urn long; girdle outer margin fringed with glassy spicules of two types, the first slender, blade- like (30x210 fmi), the other very slender and small (8-10x55-80 \xm); undersurface paved with rectangular, transparent scales about 25 x 50-100 jmi, each bearing an outer edge pro- tuberance that articulates with inner edge con- cavity of adjacent scale; girdle bridges packed with slender, blade-like spicules (10 x 1 15 j^m). Radula of 16.0 mm specimen 5.0 mm long (31% of total specimen length), with 48 rows of mature teeth; median tooth broadly rectangu- lar, about 90 \im wide at anterior blade; major lateral teeth with tricuspid head 120 ytm long, 80 ^m wide. Variation: The 27 intact specimens range in length between 1.5 and approximately 21.0 mm. No pustules are present on two specimens 1.5 and 1.8 mm in length, but a 2.2 mm specimen (IRCZM 61:062) has single large pustules at anterolateral corners of each intermediate valve, indicating that tegmental ornamentation may begin at about that size. Thereafter, large pustules of all valves apparently increase in size and number with increasing size of the animal. The largest specimen (21.0 mm; FSBC I 31760; Fig. 14) is severely eroded on all valves, par- ticularly at the junctions of lateral and central areas of the intermediate valves. The rows of small pustules of central areas extend over the jugum of all valves except iv, which remains smooth on the posterior half; indications of 19-20 pustule rows are present on some valves. In lateral areas of the 21.0 mm specimen, largest pustules tend to occur near the middle, and pustules nearest the girdle are somewhat 38 THE NAUTILUS April 29, 1985 Vol. 99(2-3) FIGS. 9-12. Single valves of Chaetopleura staphylophera n. sp. from sediments, Grand Bahama Island (all x 3.5): 9, valve VIII; Gold Rock, 24.4 m; FSBC I 31762; 10, valve VIII, Tamarind Beach reef, 4(1.8 in; 11, intermediate valve; Gold Rock, 26.2 m; 12, intermediate valve; Indian Cay, 23.0 m. [Figured specimens ld-12 in Worsfold collection]. smaller and arranged in rough, concentric arcs, giving the impression of less energetic growth with advanced age. The Bahamian specimens consist only of sin- gle valves (Figs. 9-12), but their tegmental pustular arrangements are similar to those of specimens from North Carolina and Florida. If, as seems likely, the Bahamian specimens repre- sent the new species, this may indicate that the species attains greater size than exhibited by the largest (21.0 mm) entire specimen; width of the tegmentum of valve viii of that specimen is only 5.2 mm, whereas that of the largest Baha- mian specimen is 7.3 mm. Distribution: Intact specimens of Chaeto- pleura staphylophera were examined from off Tampa Bay and Sanibel Island, Florida west coast; off Fowey Light near Miami; offshore of St. Lucie Inlet northward to St. Augustine along the Florida east coast; and southeast of Cape Lookout, North Carolina. Because all other Florida specimens were taken from depths of 53-91 m, the single record from 18 m (BMI 1143) is questioned. The North Carolina collection is from "240-350 ft" ( = 73-107 m), so that specimen may have occurred within the depth range of the Florida material or in slightly greater depths. All Bahamian specimens are from off the southwest coast of Grand Bahama Island and consist only of single valves collected by divers from sediments near reefs in 23-47 m depths, somewhat shallower than the continen- tal collections. Etymology: The specific name staphylophera, from the Greek staphyle (a bunch or cluster of grapes) and phero (to bear or carry), refers to the distinctive clusters of large, grape-like pustules on lateral areas of intermediate valves. Remarks: Porter (1974: p. 302) listed the 13 14 15 16 17 FIGS. 13 17. 13, Chaetopleura staphylophera n. sp.. holotype, 15.5 mm; west of Sanibel Island. Florida, 73m; USNM 842109; 14, C iaphylophera, paratype, 21.0 mm; 9 nmi ENE of St. Lucie Inlet, Florida, 64 m; FSBC I 3176(1; 15, Chaetopleura Ua (Say), 12. 1 mm; cast of Hutchinson Island, Florida, 91.5 m; FSB< ' I -".0767, 16. "' 'alloplax" janeirensis (Gray), 18.0 mm; Sand Ke reef, Florida, 1 m; FSBC I 31765; 17. "C "janeirensis, 16.0 mm; Riode Janeiro, Brazil, shallow; FSBC I 31768. Vol. 99(2-3) April 29. 1985 THE NAUTILUS 39 North Carolina specimen as ICalloplax janeiren- .s/.s, and Lyons (1982: p. 39) mentioned an un- described species of Chaetopleura from the Bahamas. Both reports were based upon speci- mens used in this study and which are herein described. The new species differs from Cliactuplcura apiculata (Say, 1834), the only previously known Chaetopleura species from the eastern and southern United States, by possession of much larger, more densely arrayed pustules on the end valves and on lateral areas of inter- mediate valves (Figs. 18-20). Additionally, the major lateral tooth of the radula of C. apiculata is bicuspid (Fig. 29), whereas that of the new species is tricuspid (Fig. 28). In areas where the ranges of the two species overlap latitudinally, C. apiculata usually (bul not always) occupies shallower depths than does < '. staphylophera. Other western Atlantic species of Chaetopleura are known only from the southern Caribbean or further south. These include C. candisata Shuttleworth, 1856 ( = C apiculata. fide Kaas, 1972; Kaas and Van Belle, 1980;' Ferreira, 1983a), from Cuadeloupe, and C. angulata (Spengler, 1797), C. isabellei (d'Orbigny, 1841), and <'. spiiiuliisii (Cray, 1828), all from Brazil or southward to Patagonia. Published descriptions of the last three species indicate that all possess tegmental pustules considerably smaller and more widely spaced than those of the new species. Chaetopleura carrua Righi, 1970, en- tirely lacks pustules on end valves and lateral areas of intermediate valves. Instead, Chaeto- pleura staphylophera demonstrates a close rela- tionship to Chaetopleura gemma Dall, 1879, a west American species which occurs from Van- couver Island, Canada, to Magdalena Bay, Baja, California (Burghardt and Burghardt, 1969; Putnam, 1980). That species lives in depths of 10-40 fms (18-73 m) or more according to Clark (1982), but Ferreira (1983a) reports the bathy- metric range as 0-22 m; the reason for this dis- crepancy is unknown. Like the new species, the major lateral tooth of the radula of C. gemma is tricuspid (Dall, 1879: 296, pi. 1, fig. 9). Tegmen- tum color, size and shape of pustules, and slit formula (9-12/1/7-8) of C. gemma are also similar to those of < '. staplnjlojthcra, but pustules of the lateral areas of C. gemma are arranged in 4-7 radiating rows (Pilsbry, 1892; Ferreira, 1983a), whereas those of C. staphylophera are not FIGS. 18-21. ( 'haetvpleura a pi ruin In (Say). 11.0 mm; Anclote Key, valve VIII (all x 111); 21, dorsal girdle scales ( x 600). Fieri. la. :■; m; FSBC 1 .",17li4: 18. valve I; 19, valve IV; 20. in THE NA1TI1J/S April 29, 1985 Vol. 99 (2-3) aligned except at anterior margins. Likewise, there are LO-15 longitudinal rows of pustules on centra] areas of ( '. gemma (fide Ferreira, 1983a), whereas C. staphylophera lias as many as 20 such rows. The tail valve of C. gemma illustrated by Pilsbry (1892: pi. 13, fig. 74) also differs from that of C. staphylophera, being ornamented with many radial rows of numerous beads rather than the essentially nonaligned pustules of the new species. Clim tujih/n-ii stiijihi/lD/ihirn is distinguished from Calloplax janeirensis [3.\s,o = Chi I on smccr- binna Reeve, 1847, formerly considered a species of Chaetopleura, fide Ferreira (1979)], the only other species of Chaetopleuridae in Florida and the northern Caribbean, by posses- sion in the latter of strong radial ribs (Fig. 16) or rows of loosely coalesced pustules (Figs. 17, 22-24) instead of unaligned pustules on end valves and lateral areas of intermediate valves. However, the new species resembles C. janei- rensis in the size and shape of pustules, in the 30 FIGS. 28-30. Major lateral radular teeth: 28. Chaetopleura staphylophera n. sp. (> 450); 29. Chaetopleura apiculata (x 4(iii); .'{0, "Calloplax" janeirensis ( ■ 500). TK^b, JM*^ FIGS. ■i'l-Ti. 22-25, "Calloplax" janeirensis (Cray), L0.5 mm; Dry Tortugas, Florida. 1 m; FSBC I 31767: 22, valve I; 2:t, valve tV: 21. valve VIII (all x 12); 25, dorsal girdle I • 300); 26, "C. "janeirensis, L5.5mm;Kej Vaca, 1 m; i 31766; girdle ipicule < ■ 200); 27, "C " jam irensis, ii \ aca, Florida, 1 m; FSBC I 31766; ventral girdle scale i • 300). pel 'lily surface of the interpustular tegmentum of head and tail valves (Figs. 1, 3, 22, 24). and in morphology of scales (Figs. 7, 8, 25, 26) and scattered glassy spicules (Figs. 6. 27) of the dor- sal surface of the girdle. Both species also possess radulae with tricuspid major lateral teeth, but cusps are much longer and more acute on teeth of C. staphylophera than are those of ( '. janeirensis (Fig. 30). Ferreira' s statement (1983a: p. 220) that Chaetopleura gemma "poses no diagnostic prob- lems [as a species of Chaetopleura] given its very different characteristics in shape, size and sculp- ture [including "tubercular ridges" on lateral areas]" is perplexing because that species, like C. staphylophera, also strongly resembles Calloplax janeirensis. Efforts to clarify the generic affinities of these species prompted a review of recent treatments of both genera. Thiele (1909) erected Calloplax to contain Cliihm junei rensis Gray, 1828. which occurs from Brazil to south Florida. Assigned to Chae- topleura Shuttleworth, 1853, by several authors during the latter half of the nineteenth century, ( '. janeirensis was separated from that genus by Thiele because the pustules of the head. tail, and lateral areas of intermediate valves are much Vol. 99(2-3) April 29, 1985 THE NAUTILUS 41 larger than those of species of Chaetopleura and are usually coalesced to form prominent ribs. Calloplax was placed in Chaetopleuridae by Thiele (1929) where it remained until recently. No additional species were described until A. G. Smith and Ferreira (1977) reassigned the ende- mic Galapagos species Callistochiton duncanus Dall, 1919, to Calloplax, thereby establishing the presence of the genus in the eastern Pacific; Smith and Ferreira concurrently reassigned Calloplax to Callistoplacidae. Soon thereafter, Ferriera (1978) transferred a Chilean species, Callistochiton viviparus Plate, 1899, to Calloplax, redescribed C. janeirensis and C. duncanus, reviewed synonymies of all three and retained Calloplax in Callistoplacidae. More recently, Ferreira (1982) described a third east- ern Pacific species, Calloplax hanselmani, from Peru and the Galapagos Islands northward to Mexico. In that paper, Ferreira expressed uncertainty regarding the taxonomic position of Calloplax and, after assessing similarities be- tween Calloplax, Chaetopleura and Callistochi- ton, concluded that Calloplax should be returned to Chaetopleuridae. Although Ferreira (1978, 1982) twice provided diagnostic comments for Calloplax and most recently (1983a) provided similar comments for Chaetopleura, he did not define characters separating species of the two genera. Difficulty in identifying differences between the genera has been complicated by unequal application of diagnostic characters. Thus, Ferreira's (1982) diagnosis of Calloplax mentions overall shape, tegmental ornamentation, location and config- uration of the mucro, and girdle ornamentation, whereas his (1983a) diagnosis of Chaetopleura includes comments on size, tegmental ornamen- tation, insertion plates, slits of intermediate valves, eaves, girdle ornamentation, gills, and radular morphology. To allow more equitable comparison of the two genera, information on the above characters and on girdle bridges (see Ferreira, 1983a) was compiled from species descriptions as well as diagnoses in each of Ferreira's three papers (Table 1). Information in Table 1 reveals that although some species of Chaetopleura have features (e.g., small pustules on head and tail valves and lateral areas of intermediate valves; girdle hairs; bicuspid major lateral tooth) not found on any species of Calloplax, all features except the radial ribs of some species of Calloplax are fully contained within the range of characters of Chaetopleura. In fact, Calloplax hanselmani has radial rows of unconnected pustules, not ribs, in areas where ribs customarily occur on species assigned to Calloplax. and even ribs of C. janei- TABLE 1. Diagnostic Characters in Recent Reviews1 of Chaetopleura and Callopla Character ( 'lini-tnpli'iirn < 'alloplax Size Shape Tegmentum Insertion piates Intermediate valves Eaves Mucro (lirdle ( rirdle bridges Gills Radula Small to large (8-60 mm length). Ovate (length/width ratio 1.4-1.8:1). Larger pustules in quincunx or radial rows in end valves and lateral areas of intermediate valves; smaller pustules in longitudinal rows or coalesced in riblets in central areas. With "rather sharp" teeth. Uni-slit. Solid. Posterior, central or slightly anterior concave or convex postmucro, with without additional false mucro. With minute, simple, oval to spiculoil interspersed with glassy, hyaline s] some species with horny hairs. With or without spicular elements. Holobranchial, abanal. Median tooth wide, subquadrangular; major lateral teeth tricuspid or bicuspid. with 1 scales, licules; Small to medium (13-21 mm length). Elongate (length/width ratio ca. 2:1). Strong radial ribs or rows of pustules in end valves and lateral areas of intermediate valves; longitudinal, often granulose riblets in central areas. With "CallistockitonAike" to "relatively sharp" teeth. Uni-slit. Solid. Centra] or slightly anterior, with convex postmucro. With spicules (not hairs) interspersed amidst small, ovoid, closely parked, coarsely striated scales. With or without spicular elements. | Not defined]. Median tooth wide, subquadrangular; major lateral teeth tricuspid. 'From Ferreira (1978, 1982, 1983a) 2Ranges based on largest reported sizes of various species. 42 THE NAUTILUS April 29, 1985 Vol. 99(2-3) rensis occur as rows of loosely connected pus- tules in some specimens from Florida (Figs. 22- 24) and Rio de Janeiro (Fig. 17), the type-locality of the type-species of Calloplax. This seems to eliminate the value of radial ribs as a generic character and requires the conclusion that ( 'ullopliu: is a junior synonj m of ( 'haetopleura. A brief review based upon morphological in- formation available in published literature (Pilsbry, 1892; Thiele, 1893; Plate, 1899; Righi, 1967, 1970; Bullock, 1972; Ferreira, 1978, 1982, 1983a) suggests that most of the 22 New World species of Chaetopleuridae are separable into two groups as defined by Pilsbry (1892: p. 28): "(1) typical forms, rather large, and having very delicate sculpture; and (2) group of C. gemma, having the lateral areas strongly raised and coarsely sculptured." These groups approximate those previously allotted to Chaetopleura and Calloplax, but some "intermediate" species do not conform fully to either group (Table 2). The first group is comprised of species with bicuspid lateral radular teeth, corneous girdle hairs in addition to scales and glassy spicules, and small tegmental pustules widely scattered or separated in rows. This group includes Chae- topleura angulata (Spengler, 1797), C. apinilatu (Say, 1834), C. asperrima (Gould, 1852), C. hen- nahi (Gray, 1828), C. iquiquensis (Plate, 1899) and C. peruviana (Lamarck, 1819). Radulae of C. benaventei Plate, 1899, and C. fernandensis Plate, 1899, have not been described, but these species closely resemble C. peruviana and C. i/ptiiptrttsis, respectively, in other characters (see Ferreira, 1983a: p. 221), so they also may belong to this group. Ferreira (1983a) implied that C. unilineata Leloup, 1954, lacks girdle hairs, but a photograph (his fig. 28) seems to show scattered hairs on the girdle of that species; if present, they would place C. unili- neata in this group as well. I am unable to ascer- tain whether C. isabellei (d'Orbigny, 1841) or C. TABLE 2. Groupings of New World Chaetopleura species, based upon features of the girdle, radula and tegmentum. •s. •f. w y: ■s. -- V QJ 0; — 3 3 3 3 Ja — +j ~ cfl 7i _r- 7 rt J3 Tfi = w [fl u 3 ~ = u - S]iccn'.- ~3 -c 5 is 3 ■s. "5s — — 5 — 'S Ifl ta '-5 c S — "5 - — "o C IN v "P. ■= c Q> "js S- 0) ^ 0) B V Q) E & S £ J 3 5 0> 0) a. Z 3 j B — E ~ V E - he be ^ fa ■- - E ~ ' ' carrua X X 7 C. angulata X X X ( ' apiculata X X X ( '. asperrima X X X < '. hennahi X X X < ', iquiquensis X X X ' ' peruviana X X X < ' I,, naventei 7 X X i ' fernandensis 7 1 X X C isabellei X ? X C. spinulosa X 7 X i ' unilineata X 7 X i ' scabricula X X X C lanuginosa \ X X I ' roddae X X X < '. skyana X X X i ' gemma X X X i ' hanselmani X \ X i ' jam - X X X • ilopfu ra X X X < '. duncana X X X ipara X X X Vol. 99(2-3) April 29, 1985 THE NAUTILI'S 43 spinulosa (Gray, 1828) have girdle hairs; if so, those species also belong here. The type-speeies of Chaetopleura is Chiton peruvianus Lamarck [subsequent designation, Dall (1879)], so species in this group would best typify Chaetopleura s.s. Although central areas of its intermediate valves bear rows of tiny, coalesced pustules, Chaetopleura cumin Righi, 1970, entirely lacks tegmental pustules on head and tail valves and on lateral areas of intermediate valves. In this regard, C. carrua resembles C. angulata. a species in which tegmental pustules may be nearly obsolete. Its bicuspid radula appears to ally C. carrua with the above group. Chaetopleura scabricula (Sowerby, 1832) also resembles species in the above group by having small tegmental pustules and distinct girdle hairs but differs by having tricuspid lateral teeth. Chaetopleura, lanuginosa (Dall, 1879) likewise resembles species in the first group by having small, scattered tubercles but lacks girdle hairs and has tricuspid lateral teeth. Chaetopleura roddae Ferreira, 1983, and C. shyana Ferreira, 1983, each lack girdle hairs, have tricuspid lateral teeth, and have densely packed unaligned tegmental pustules on head and tail valves and lateral areas of intermediate valves. Although relatively smaller than pus- tules on species in the following group, densities and arrangements of these pustules are sug- gestive of some species in that group. The next group includes C. janeirensis, the type-species of Calloplax. In addition, Chaeto- pleura gemma Dall, 1879, C staphylophera, n. sp., and C. hanselmani (Ferreira, 1982) all lack girdle hairs, have tricuspid lateral teeth, and have large tegmental pustules on the head and tail valves and lateral areas of intermediate valves. Pustules may be unaligned (C. staphy- lophera) or arranged in rows (C. gemma, C. hanselmani, C. janeirensis) which sometimes in C. janeirensis coalesce into radial ribs; two or more such ribs may occur on lateral areas of in- termediate valves. Girdle scales and spicules of species in this group resemble those of other species in the group moreso than they resemble those of any other Chaetopleura species (for ex- ample, see C. apiculata. Fig. 21). Chaetopleura duncana (Dall, 1919) and C. ririparn (Plate, 1899) pose additional problems in placement. Each lacks girdle hairs, has tricus- pid lateral teeth, has strong radial ribs on head and tail valves, and has only two such ribs on lateral areas of intermediate valves. The low, conical or dome-like girdle scales of these species as illustrated by Ferreira (1978) are dis- similar from any other species of Chaeto- pleuridae. Additionally, there are at least three species of Chaetopleura in South Africa, possibly two in west Africa, one in east Africa, and one in east Asia (Ferreira, 1983a, b). Insufficient informa- tion is available to determine where most of these fit in the above arrangement. Acknowledgments Hugh J. Porter, University of North Carolina Marine Science Institute, Morehead City, pro- vided his previously reported specimen for study. John Reed and Dr. Robert A vent allowed study of material collected during their study of the deep-water Oculina reef community, spon- sored by the Harbor Branch Foundation, off central eastern Florida. Johnnie Johnson, Brevard Museum, Inc., provided specimens from the calico scallop grounds near Cape Canaveral. Jack N. Worsfold, Freeport, Grand Bahama, provided the single valves from that area. Lana Tester, formerly FDNR Bureau of Marine Research, produced the SEM photo- micrographs, and Sally D. Kaicher provided additional darkroom assistance. Dr. James F. Quinn, Jr., FDNR, provided guidance in Greek grammar. All are gratefully thanked. LITERATURE CITED Avent. R. M., M. E. King and R. H. Gore. 1977. Trophic and faunal studies of shelf-edge prominences off the central eastern Florida coast. Int. Revue ges. HydrobioL 62: 18.5-208. Bullock, R. C. 1972. On the taxonomy of ( 'haetopleurafulva (Wood, 1815)(Mollusca: Polyplacophora). Occ. Pap. Moll, Mus. Comp. Zool, Harvard Univ. 3(42):177-191. Burghardt. G. and L. K. Bunrhardt. Hni9. A collector's guide to west coast chitons. Spec. Publ. No. 4, San Francisco Aquarium Soc, Inc. 45 pp., 4 pis. Clark, R. N. 1982. Chitons of the north-east Pacific. Of Sea and Shore 12(3): 147-153. Dall, W. H. 1879. Report on the limpets and chitons of the Alaskan and Arctic regions, with descriptions of genera and species believed to lie new. Proc. U.S. Natl Mus. 1:281-344, 5 pis. 1919. Descriptions of new species of chitons from the Pacific coast of America. Proc. U.S. Natl. Mus. 55(2283):449-516. 44 THE NAUTILI'S April 29, 1985 Vol. 99(2-3) Ferreira, A. J. L978. The genus Calloplaj- Thiele, 1909 (Mollusca: Polyplacophora) in the Americas. Bull. So. Calif. Acad. Sci. 77(2):56-64. 1979. The genus Callistochiton Dall. 1879 (Mollusca: Polyplacophora) in the eastern Pacific, with the description of a new species. Veliger 21(4):444-466, 3 pis. 1982. A new species of Calloplaj (Mollusca: Polyplacophora) in the eastern Pacific. Veliger 24(4): 321-324, 1 pi. 1983a. The genus Chaetopleura Shuttleworth, 1853 (Mollusca: Polyplacophora) in the warm-temperate and tropical eastern Pacific, southern California to Peru, with the description of two new species. Veliger 25(3): 203-224, 4 pis. 1983b. Researches on the coast of Somalia. The Chiton fauna (Mollusca Polyplacophora). Hal. J. Zoo/., n.s., Suppl. 18, 9:249-297. Gray, J. E. 1828. Spicilegia Zoological or Original Figures and Short Systematic Descriptions of New and Unfigured Animals. Part 1: 8 pp, 6 pis. British Museum. Joyce, E. A., Jr. and J. Williams. 1969. Rationale and pertinent data. Mem. Hourglass Cruises 1(1): 1—50. Kaas, P. 1972. Polyplacophora of the Caribbean region. Stud. Fauna Curasao and other Caribb. Ids. 41(137): 1-162, pis. 1-9. Kaas, P. and R. A. Van Belle. 1980. Catalogue of Living Chitons. W. Backhuys, Rotterdam. 144 pp. Kennedy, F. S., Jr., J. J. Crane, R. A. Schlieder and D. G. Barber. 1977. Studies of the rock shrimp, Sicyonia brevirostris, a new fishery resource on Florida's Atlantic shelf. Flo. Mar. Res. Publ. No. 27. 69 pp. Lyons, W. G. 1982. Comments on chitons (Mollusca: Poly- placophora) of the Bahama Islands. Bull. Am. Malaeol. Union 1982: 38, 39. Abstract. Orbigny, A. d'. 1841. Voyage dans VAmerique Meridionale (1826-1833), 5(3):482-489. Pilsbry, H. A. 1892. Polyplacophora, (Chitons). Lepido- pleuridae, Ischnochitonidae, Chitonidae, Mopaliidae. Manual ofConchology 14:1-350, pis. 1-68. Plate, L. H. 1899. Die anatomie und phylogenie der chitonen. Fauna Chilensis. Zool, Jahrb. 5(11):15-216, pis. 2-11. Porter, H. C. 1974. The North Carolina marine and estnarine Mollusca; an atlas of occurrence. Univ. North Carolina Inst. Mar. Sci., vi + 351 pp. Putnam, B. F. 1980. Taxonomic identification key to the described species of polyplacophoran mollusks of the west coast of North America (north of Mexico). Pacific Gas and Electric Co., Dept. of Engineering Research, Rpt. 411- 79.342. 164 pp. Reed, J. K, R. H. Gore, L. E. Scottoand K. A. Wilson. 1982. Community composition, structure, areal and trophic relationships of decapods associated with shallow- and deep-water Oculina varicosa reefs: Studies on Decapod Crustacea from the Indian River region of Florida, XXIV. Bull, Mar. Sci. 32(3):761-786. Reeve, L. A. 1847. Monograph of the genus Chitnn. ' 'onch. lam. 4, 28 pis. Righi, G. 1967. Sobre Polyplacophora do litoral Brasileiro. Pap. Avul. Zool. Sao Paulo, 20(9):85-97. 1970. Mollusques polyplacophores. Resultats scientifiques des campagnes de la "Calypso" au large des cotes Atlantiques de VAmerique du Sud (1961-1962) 9(19):107-114. Say, T. 1834. American rmichology. or descriptions of the shells of North America. Part 7. Appendix. Shuttleworth, R. 1853. Uber den Bau der Chitoniden, mit Aufzahlung der die Antillen und die Canarischen Inseln bewohnenden Arten. Mitth. Naturf. Ges. Bern (286-291): 169-207. 1856. Description de nouvelles especes. Premiere decade: especes nouvelles pour la faune des Antilles. Jour, de Conchyl. 5:168-175. Smith, A. G. and A. J. Ferreira. 1977. Chiton fauna of the Galapagos Islands. Veliger 20(2):82-97. 4 pis. Spengler, L. 1797. Udforlig Beskrivelse ovet det manges- kallede Konkylie-Slaegt af Linnaeus kaldet Chiton met endeel nye Arten og Varieter. SkrivL Naturkist. Selsk. 4(0:62-1 03. Thiele, J. 1893. Polyplacophora, Lepidoglossa, Schuppen- zilngler. Pp. 353-401, pis. 30-32 in F. H. Troschel. Das Gebiss der Schnecken zur Begriindung einer naturliehen Classification, 2. 1909. Revision des Systems der Chitonen. Teil I. Chun's Zoologiea 22(56):l-70, figs. A-E, pis. 1-6. 1929. Handbuch der systematischen Weichtier- kunde. Loricata. 1(1): 1-22. Jena. Conchologists of America The annual meeting of the Conchologists of America will be held in Philadelphia June 22-26, 1985, where it will be hosted by the Philadelphia Shell Club at the Academy of Natural Sciences of Philadelphia and a nearby hotel. For reserva- tion forms write: Frank Roach, 1028 Belvoir Rd., Norristown, PA 19401. 1985 AMU Meeting The American Malacological Union will hold its annual meeting on the campus of the Univer- sity of Rhode Island on July 29-August 3, 1985. For further information please contact Dr. M. R. Carriker, College of Marine Studies, Univer- sity of Delaware, Lewes, DE 19958. Vol. 99 (2-3) April 29, 1985 THE NAUTILUS 45 ARENE FLEXISPINA. A NEW SPECIES (GASTROPODA: LIOTIIDAE) FROM OFF EASTERN BRAZIL Jose Henrique N. Leal1 and Arnaldo C. dos Santos Coelho Setor de Malacologia2 - Museu National 20.942 - Rio de Janeiro, RJ - Brasil Seven species of the genus Arene H. & A. Adams, 1854 are already known from the Brazil- ian coast: Arene tricarinata (Stearns, 1872), A. briareus (Dall, 1881), A. variabilis (Dall, 1889), A. bairdii (Dall, 1889), A. brasiliana (Dall, 1927), A. riisei Rehder, 1943 (Abbott, 1974; Rios, 1975) and A. notialis Marini, 1975 (Marini, 1975). The present description is based on speci- mens obtained through bottom sampling (van Veen and Petersen grabs) between 54 and 82 meter depth during the GEOMAR X cruise undertaken by the Brazilian Navy research vessel "N.Oc. Almirante Camara" along the eastern coast of Brazil, in the period of 01-11 June 1978. Sampled substrate in the three sta- tions where the species was found consisted of fragments of calcareous algae and calcareous gravel. Although soft parts are not preserved, thus making difficult a more accurate taxonomic characterization, shell features are markedly distinct. Arene flexispina new species (Figs. 1-3) Description: Shell small, solid, trochoid in shape, reddish brown, with spiral rows and spines of lighter color. Ratio height/width of the shell higher in adults than in younger speci- mens. Whorls 5V2, the first IV2 comprising the protoconch, white and smooth, lower than the subsequent whorl. Teleoconch whorls with 2 larger peripheral spiral rows of 10 or 11 large, fluted spines spirally raised and imbricated. Narrower row 1-2 subsutural, one intermediate (between the 2 larger) and one immediately above the subsequent whorl, with numerous im- bricated scale-like spines, smaller than those in the 2 larger rows. Finely incised axial lines on entire shell microscopic and crowded. Suture 'Present address: B.L.R., Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149 Contribution no. 46 channeled, clearly defined. Body whorl rounded, with wider spiral cords; spines in the 2 larger cords triangular, bent outwards and sharply pointed in apical view; spines number the same as in the spire. Base with 4 or 5 well-separated beaded spiral cords; beads almost imperceptible in worn specimens. Cord bordering the umbili- cus the same size or only slightly larger than the other basal cords (younger specimens). Um- bilicus wide, deep and twisted, with fine axial lines internally. One or two cords entering the umbilicus in younger shells, absent in mature specimens. Aperture whitish, oblique. Outer lip thin, with crenulations corresponding to the ex- ternal spiral ornamentation. Operculum round, multispiral, with small radial lines giving beaded aspect to its calcareous external surface. Attachment side horny and convex. Material examined: GEOMAR X station 048, 40 km off Ponta de Corumbau, Bahia, Brazil (16°56'30"S, 38°39'30"W), 80 m depth, "N.Oc. Almirante Camara" col. 09 June 1978, Holotype, Museu National, Rio de Janeiro, Brazil (Col.Mol. MN 5352), height 6.4 mm, width 6.7 mm; Para- type 1, United States National Museum, Wash- ington, D.C. (USNM 820786), height 5.4 mm, width 6.2 mm; Paratype 2 (Col.Mol.MN 5353), height 4.7 mm, width 5.4 mm; Paratype 3, Museu Oceanografico, Fundacao Universidade do Rio Grande, Rio Grande, Brazil (MORG 22807), height 3.5 mm, width 4.5 mm; Paratype 4 (USNM 820786A), height 3.4 mm, width 4.3 mm; Paratype 5 (MORG 22808), height 3.2 mm, width 4.3 mm; GEOMAR X station 038, 170 km off Conceicao da Barra, Espirito Santo, Brazil (18°49'00"S, 37°52'00"W), 54 m depth, "N.Oc. Almirante Camara" col. 07 June 1978, Paratype 6 (MORG 22619), height 2.0 mm, width 3.0 mm; GEOMAR X station 047, 120 km off Abrolhos Reef, Bahia, Brazil (17°44'00"S, 37°21'00"W), 54 m depth, "N.Oc. Almirante Camara" col. 08 June 1978, Paratype 7 (Col.Mol.MN 5354), height 1.4 mm, width 2.4 mm. 46 THE NAUTILUS April 29, 1985 Vol. 99(2-3) FIGS. 1-3. Arene flexispina n. sp. 1 and 2, Apertural and ventral views of the holotype, Col.Mol.MN 5352, 40 km off de Corumbau, Bahia State, Brazil. Scale bar=2 mm. .'!. Apertural view with operculum of the paratype >'<. MORG ■ off ( 'onceicao da Barra, Espirito Santo State, Brazil. Scale bar= 1 mm. Type locality: Brazil, Bahia State, 40 km off Ponta do Corumbau, (16°56'30"S, 38°39'30"W), 80 m depth, calcareous algae bottom (Fig. 4). Etymology: The specific name stands for the large outwardly bent spines in the spiral cords of the spire and body whorl. Remarks: The species seems to belong in the subgenus Arene s.s. which is, as stated by Keen (1971:345), characterized by a sculpture of coarsely beaded spiral cording on the body whorl and base, the periphery rounded or stellate. Although A. flexispina n. sp. possesses some of the characters of the subgenus Mareval- vata Olsson & Harbison, 1953, such as general outline, spiral cords in the umbilicus wanting in mature specimens and outer lip not thickened, it doesn't exhibit the diagnostic flattened base with radial lines extended from the umbilicus and a nacreous inner layer (Olsson & Harbison, 1953:348; Keen, 1971:346). Further investiga- tions or a revision work on the western Atlantic species of Arene seems to be necessary to con- firm the positioning of A. flexispina at subgeneric level. 17 18 BAHIA STATE BRAZIL 048 ABROLHOS REEF COMPLEX 047 038 FIG. 4. Location of the three GE( >MAK X stations in which Arene flexispina n. sp. was found (solid triangles). The type lecality is represented by station (MS. Inset shows position of the area in southern Atlantic Ocean. Vol. 99(2-3) April 29, 1985 THE NAUTILUS 47 It was observed from the shell measures of the 8 examined specimens of A. Jlexispina that the ratio height/width increases as the shell grows, suggesting a pattern of allometrie growth (Fig. 5), probably a consequence of a gradual altera- tion in the angle of coiling in the species. A rene Jlexispina appears to be related to A. briareus from the Caribbean and tropical west- ern Atlantic, according to the original descrip- tion (Dall, 1881:52), and later illustration by the same author (Dall, 1889: pi. 24, figs. 5, 5a), and by comparison of specimens (Col.Mol.MN 5390; Morg 14.969), mainly by its elevated spire and spinose ornamentation. A. jlexispina differs, however, by its darker color, two obviously larger cords on body whorl, which are all about the same size or only a little larger than the re- maining in briareus; ornamentation of the spiral cords consisting in about 11 large fluted spines, instead of about 40 small spines in briareus; a well differentiated ridge or cord around the um- bilicus and a nodulose spiral ridge inside it in briareus, not present in Jlexispina; outer lip thicker in briareus. Arene notialis from off southeastern Brazil differs by its whitish color, lower spire, about 21 8 { V- 6 c_S -O I m b Q X. • 3 3 n "j 2 Cf3 J •—A A. ^^i 1 - — w — - width (mm) FIG. 5. Allometrie shell growth in Arene jlexispina n. sp.; sketches illustrate the shape of shells at three points on the curve: a) Paratype 7, Col.Mol.MN 5354, height 1.4 mm, width 2.4mm; b) Paratype 3. MORG 22807, height 3.5 mm, width 4.5 mm; c) Holotype. Col.Mol.MN 5352, height 6.4 mm, width 6.7 mm. Scale bars= 1 mm. nodules (not spines) on spiral cords in the body whorl, 8 joined strongly beaded basal spiral cords instead of 5 separated cords in Jlexispina; umbilicus smaller and straight, bordered by a larger basal cord and outer lip thicker in notialis, according to Marini (1975) and material examined of A. notialis from off Guarapari, Espirito Santo, Brazil, "N.Oc. Almirante Saldanha" col. September 1968, 80 m depth, Col.Mol.MN 4862, two specimens. Acknowledgments We are indebted to Dr. Donald R. Moore from the Rosenstiel School of Marine and Atmos- pheric Science, Miami, for the critical review of the manuscript, to the staff at Departamento de Hidrografia e Navegacao, Ministerio da Marinha, Brazil, for providing the adequate con- ditions to the obtention of the material exa- mined, during the GEOMAR X cruise, to Prof. Eliezer de C. Rios, Museu Oceanografico, Rio Grande, Brazil, who made available part of the studied material and to Mr. Raul Garcia, Rio de Janeiro, Brazil, for the drawings of Arene Jlex- ispina. LITERATURE CITED Abbott, R. T. 1974. American Seashells (2nd Edition). Van Nostrand-Reinhold, New York, 663 pp. Dall, W. H. 1881. Reports on the Results of Dredging, under the Supervision of Alexander Agassiz, in the Gulf of Mexico, and in the Caribbean Sea, 1877-79, by the United States Coast Survey Steamer "Blake", . . . XV. Prelimi- nary Report on the Mollusca. Bull. Mus. Comp. Zooi. Harvard Univ., Cambridge 12(6):171-318, pis. 1-9. 1889. Reports on the Results of Dredging, under the Supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78) and in the Caribbean Sea (1879-80), by the U.S. Coast Survey Steamer "Blake", . . . XXIX. - Report on the Mollusca. Part II. - Gastropoda and Scapho- poda. Bull. Mus. Comp. Zool. Harvard Univ., Cambridge 18:1-492. 31 pis. Keen, A. M. 1971. Sea Shells of Tropical West America. Stanford University Press, Stanford, 1064 pp. Marini, A. C. 1975. Sobre duas especies novas de micro- moluscos (Trochacea: Turbinidae; Liotiidae) da costa brasileira. Pap. Ainil. Zool. St. Paulo 29(5):31-34, 2 pis. Olsson, A. A. and A. Harbison. 1953. Pliocene Mollusca of Southern Florida, with special reference to those from North Saint Petersburg with special chapters on Turridae by Williams G. Fargo and Vitrinellidae and Fresh-water Mollusks by Henry A. Pilsbry. Acad. Nat. Sci. Philad.. Monog. 8:1-457, 65 pis. Rios, E. C. 1975. Brazilian Marine Mollusks Iconography: Fundacao Universidade do Rio Grande, Rio Grande, 331 pp., 91 pis. 48 THE NAUTILUS April 29, 1985 Vol. 99(2-3) AN EXCEPTIONAL STREAM POPULATION OF THE BANDED APPLE SNAIL, VIVIPARUS GEORGIANUS, IN MICHIGAN Gary L. Pace and Ernest J. Szuch Department of Biology University of Michigan-Flint Flint, MI 48502-2186 ABSTRACT SCUBA and a Surber sampler were used to study a stream population of Viviparus georgianus (Lea). This locality, at the mouth ofRunyan Creek where it flows into Hoisington Lake in Livingston County, Michigan, is only the fourth known locality for any species of Viviparus in that state. Densities were high (up to 86^/m2) and varied significantly with gender (female > male), station type (reach > meander), and station position (upstream > downstream). Mean weight varied in the same ways with respect to gender and station type, but conversely for station position (whether downstream or upstream). The only effective interaction between factors was that between gender and station position: females decreased in size upstream faster than males. Weight -frequency data combined for all sta- tions supported the independent measures of sex ratio (females > males) and sex- ual dimorphism in size. The main purpose of this paper is to draw at- tention to the fourth known population of Vivi- parus georgianus from Michigan. Voucher specimens have been deposited in the University of Michigan Museum of Zoology. The population thrives in Runyan Creek where it flows into Hoisington Lake in northern Livingston Coun- ty. Here the stream is narrow (less than 6 m), steep-sided, and varies in depth from 85 to 156 cm as it meanders through an extensive marsh. The substrate is largely organic detritus con- tributed from marsh and stream plants (e.g., Spartina pectinata, Scirpus lineatus, Typha latifolia, Nuphar variegatum, Lythrum deco- don). Our interest in this population derives from the rarity of this species in Michigan and from the very high densities found in a locality which must be very near this species' northern limits of distribution. Since its discovery by two of our students, Donald House and Philip Davis, several papers have been published on the physiology of these snails (Fitch, 1975, 1976; Buckingham & Freed, 1976; Davis & Fenner, 1977; Studier & Pace, 1978). Ecological studies on this and related species include those of Van Cleave & Lederer (1932), Stanczykowska, et al. (1971, 1972), Burla (1972), Samochwalenko & Stanczykowska (1972), Young (1975), de Bernardi, et al. (1976), Brown (1978), Plinski, et al. (1978), Vail (1978), Imlay, et al. (1981), Jokinen (1982) and Thomp- son (1985). The main studies of the systematics and distribution of North American viviparids were those of Clench (1962) and Clench & Fuller (1965). Materials and Methods Many species of temperate, freshwater mol- lusks including Viviparus, move to deeper water, burrow into the substrate, and become less active during the Fall and Winter (Burla, 1972; Young, 1975). Therefore, when dredging and SCUBA assisted visual search methods have been used to collect these mollusks, this Fall migration has resulted in the under- sampling of the population (Burla, 1972; Young, 1975; de Bernardi, et al. 1976). In narrow, steep- sided channels, however, this Fall migratory behavior serves to concentrate the population into the bottom detritus. Under these circum- stances, the Fall may very well be the best single time of the year to study certain popula- tion characteristics. During the last week of September, SCUBA, was used to collect three Surber samples (0.093 m2 x 7.62 cm) at each of 12 stations selected at the centers of consecutive stream meanders and reaches. Since samples were collected from Vol. 99(2-3) April 29, 1985 THE NAUTILUS 49 meanders and reaches whose radii and lengths varied considerably, stream channel distances between stations were not equal. The samples were taken from the deepest part of the stream cross-section with minor adjustments where water-lily rhizomes prevented forcing the sampler fully into the substrate. Everything within the frame was then scooped into the Surber net, brought to the surface, and trans- ferred to labeled plastic containers for transport to the laboratory. In the lab, snails were sorted from the detritus, sexed, and then weighed on a top-loading balance to 0.01 g. Wet (live) body weight was used since Davis and Fenner (1977) showed its direct relationship to dry weight for these snails. Results' Total densities ranged from 151/m2 to a max- imum of 864/m2. The average population den- sities were significantly higher in the reaches (608/m2) than in the meanders (534/m2). Closer examination showed that the average density of the males was the same in these two types of habitats (243:228/m2). The difference, therefore, was in the number of females (365:306/m2). While females outnumbered males in all stations combined (female/male = 1.42), the difference was greater in reaches (female/male = 1.50) than in meanders (female/male = 1.34). A comparison was also made between the six most down- stream stations and the six most upstream sta- tions. An average density of 462/m2 was found for the downstream populations, while that of the upstream group was 680/m2. Thus, the upstream populations were significantly denser than the downstream populations. Live body- weight averages computed for each station (sexes combined) ranged from 0.75-1.97 g. The average size of the reach snails (1.57 g) was larger than that of the meander snails (1.35 g). Also, the average size of the females (1.90 g) was nearly twice that of the males (1.01 g). Fur- thermore, while the average size of both sexes decreased upstream, females decreased faster than males (Fig. 1). Frequency distributions of weight classes for each sex were constructed for each station 1.0 ' :! j^- * i T I I i — ■ — ^___ i I T — — «»1^ ' i 1 1 'Readers wishing tabular data on density and mean weight distributions among the stations along with their statistical analyses may write the authors for copies. 4-5 6-7 8-9 10-11 12-13 14-15 S tation No (Upstream -*) FIG. 1. Rates of change in male and female mean weights with stream position. Each point represents the mean of 20 meander and 20 reach snails selected randomly. The vertical bars represent +/- 2 Standard Errors. The curves are regression lines based on the mean weights for males and females separately. Females: Intercept = 2.378, Slope = -0.162. Males: Intercept = 1.308, Slope = -0.088. separately and for all stations combined. All curves for both sexes showed bimodal distribu- tions of weight classes. Because the results were comparable for all stations, curves are provided only for the combined data (Fig. 2). We assume that size is at least roughly correlated with age (de Bernardi, et al., 1976) and we will refer to the obvious groupings in Fig. 2 as cohorts. The younger cohort for each sex had a mode at about 0.5 g, and ranged from 0.2-0.8 g for males and from 0.2-1.0 g for females. Females were slightly larger than males in this cohort, and outnumbered males 616 to 518. In the older cohort, 358 males weighed from 0.9-3.5 g, while 606 females weighed from 1.1-8.9 g. These curves, as well as the data already discussed in- dicate that the average adult female is nearly twice as large as the average adult male. Note also that there is no significant difference be- tween the number of females in the two cohorts (616 & 606) and that in each, females out- numbered males (518 & 358). Finally, note that males were more numerous in the younger cohort than in the older one. Discussion As the papers by Clench (1962) and Clench & Fuller (1965) have documented, Viviparus i/mri/nunis (Lea) has apparently only invaded 50 THE NAUTILUS April 29, 1985 Vol. 99 (2-3) — Mole -_ Femole it ft « « \ A A r*V-- 10 20 30 40 50 60 70 Wl |gm) FIG. 2. Weight-frequency curves for all snails, sexes separate. the northern states during the last century. Fur- thermore, Clench pointed out that only three localities are known from Michigan, and that these have been presented to the University of Michigan Museum of Zoology since the publica- tion of Winslow's (1926) checklist of Michigan mollusks: UMMZ 166266 and 177214: Coguac Lake, 2 mi S.W. Battle Creek, Calhoun Co., Leslie Hubricht. Oct. 6, 1946; UMMZ 167226: Park N. of Owasso, Shiawassee Co., H. van der Schalie & Aurele LaRocque. July 10, 1947; UMMZ 173445: S. side Silver Lake, 15 mi N.E. Grand Rapids, Kent Co., C. D. Nelson. (No date recorded). While it is possible that any specific locality may have long been populated and yet over- looked by collectors, it must be admitted that \'irij„,rus is rare in Michigan. It is well-known that Michigan's molluscan fauna has long been among the best known in the world. Neverthe- less, the above four lots of V. georgianus are in contrast to hundreds of lots of Michigan Campeloma integrum and C. decisum which fill 5 and 7 UMMZ cabinet drawers, respectively. Not only is this one of the few Michigan localities for Viviparus, but it appears that among those so far reported, this locality most closely approaches this species' optimal habitat. This is supported by the fact that the population reached a maximum density of 864/mi and a maximum standing crop biomass (density x average live weight) of 1163 g/m2. These data are higher than any yet reported for this species (Van Cleave & Lederer, 1932; Vail, 1978; Browne, 1978). Furthermore, these data exceed those for any freshwater snails (Hyman, 1967) and may prove to represent one of the largest standing crop biomass records among fresh- water gastropods. These results are unexpected for a locality so near the northern limits of a species' range. The timing and method of collec- tion must certainly have contributed to these high numbers (see Materials and Methods). The substrate in this habitat is very rich in organic detritus derived from the breakdown of the plants of the extensive marsh through which Runyan Creek slowly meanders. Earlier reports of a fine detritus habitat preference (Harman, 1972), and of combined detritus (Fretter & Graham, 1978) and filter (Cook, 1949) feeding methods by Viviparus species, provide some ex- planation for the optimal nature of this habitat. It certainly seems better suited to this species than its usually reported habitat "on the bottom Vol. 99 (2-3) April 29, 1985 THE NAUTILUS 51 of mesotrophic or eutrophic lakes and ponds" (Browne, 1978). Indeed, at the mouth of Runyan Creek into Hoisington Lake, the density of these snails drops to less than one snail per square meter. The fact that these snails thrive in this detritus-rich habitat so near to their northern limits of distribution may indicate that food availability outweighs temperature or length of growing season in determining their optimal habitat. Both sexual size dimorphism and disparate sex ratios have previously been recorded for northern populations of this (Van Cleave & Lederer, 1932; Browne, 1978) and other species of viviparids (Annandale & Sewell, 1921; van der Schalie, 1965; de Bernaardi, et aL, 1976; Vail, 1978). In Vail's (1978) Florida populations of Viviparus georgianus, however, sexual size dimorphism did not occur, and differences in sex ratios were not noted. Thus there seems to be both local and geographical variation in these sexual attributes. In our studies, variation in sex ratio could not be shown to be dependent on any of the following variables: station type (meander vs reach), station position (upstream vs down- stream), water depth, water temperature, total density, or total biomass. Our large sample sizes, however, reduce the possibility that the variation is the result of sampling error. That these sexual differences are due to higher female growth rates and longer female longe- vity is suggested by our size-frequency data (Fig. 2) which support the findings of others (Van Cleave & Lederer, 1932; Browne, 1978). Because we made our collections in late September, our cohorts represent snails that had survived one growing season (about 4 months) and those which had survived at least two growing seasons and one winter (16-19 months). Some differential mortality (males > females) and differential growth (females > males) was evident by the end of the first grow- ing season and increased substantially by the end of the second. That these differences are not due to differential numbers and size at birth is supported on both factual and theoretical grounds. Van Cleave and Lederer (1932) found that the two sexes were present in equal numbers at birth. Fisher showed long ago that this is to be expected if there is no sexual dif- ference in energy costs (i.e., no difference in size) of the progeny to the parent (Pianka, 1974). Brown (1978), on bioenergetic and anatomical grounds suggested that "selection probably drives females toward a larger size than males as a consequence of the cost of viviparity." Furthermore, Browne pointed out that males have two options in dividing their energy resources. Evidently, some males devote much of the first year in feeding and survival, with most reproductive effort delayed until the second growing season. Other males might spend most of their time and energy actively seeking females while spending relatively less time feeding. While the latter were characteris- tic of Browne's populations and would generally be expected to leave more progeny, variation in such strategies could account for some of the variation in the distribution of sexual differ- ences in size and number. The fact that these snails are larger and more numerous in reaches than in meanders seems more easily testable. Higher currents in the meanders may reasonably be expected to re- move both young snails and detritus and deposit them in the reaches. Even if the current rarely displaces snails, the cumulative effect of erosion and deposition on habitat enrichment in the reaches could account for the differences in snail density and biomass. Analysis of the variation of the current velocity and sediment load between habitat types and between seasons would be very helpful in answering these questions. It is perplexing that density and biomass in- crease upstream while mean weights decrease (see Results). Since biomass increases upstream we might inquire whether the carrying capacity {e.g., as determined by food availability) in- creases upstream, or whether the upstream pop- ulations are more efficient in filling their niche. The first seems a more testable question. Because upstream populations are denser but individuals are smaller, we may ask whether or not these snails are stunted as a result of crowding {i.e., intraspecific competition). Also, the larger size but lower density of the down- stream snails may indicate that while some ex- trinsic factor controls numbers, surviving snails have ecological room for growth (i.e., crowding reduced). Higher predation pressure on small downstream snails could account for such popu- lation characteristics. The seasonally dense 52 THE NAUTILI'S April 29, 1985 Vol. 99(2-3) populations of ducks and geese on Hoisington Lake and the possibility of lake fish foraging some distance upstream could provide the gra- dient in predation pressure. The importance of ducks as mollusk predators is well known (Malone, 1965; Thompson, 1973). de Bernardi et al. (1978) attribute substantial modification of population structure to predation by ducks, and Price (1957) has shown the importance of lake fish predation on viviparids. Small snails with their weaker shells would be subject to higher predation rates than large snails. In other words, snails that survive to a certain size have escaped a major source of mortality (i.e., preda- tion). These snails, relatively few in number, would not be subjected to high intraspecific com- petition and would grow to a relatively large size. That stunting is occurring upstream might also be inferred from the fact that females get larger faster than males as we sample further and further downstream. Since females seem to have higher growth rates and greater reproduc- tive energy requirements (because of vivipar- ity), they may be more easily stunted in the more crowded upstream habitats. Conversely, under conditions of lower density and presumed higher detritus deposition downstream, females may be freer to express their genetically deter- mined faster growing rates. The above specula- tion obviously suggests a variety of future studies. These would include analyses of the relative organic content and depth of sediments in the different stream habitats. In addition, it would be beneficial to observe the feeding behavior of potential predators, and to actually examine their stomach contents. Furthermore, predator and competitor exclusion pens could be set up in the various habitats to test the actual effects of these factors. Finally, laboratory and field growth experiments would be invaluable in testing our hypotheses. Acknowledgments The authors are grateful to Phillip Davis and Donald House for pointing out the existence of this population, and Gregory Panos, III, for help with collecting the snails. Theodore Herzog of our Computer Center was especially helpful in processing the data. We are particularly in- debted to Dr. Richard W. Dapson for his sub- stantial assistance in the statistical analysis of these data and to Dr. Eugene Studier for critically reading the manuscript. The research for this project was assisted by grants from the Faculty Development Fund of the University of Michigan-Flint. LITERATURE CITED Annandale, N. and R. B. S. Sewell. 1921. The banded pond snail of India. Rcc Indian Mus. 22:217-292. Browne, R. A. 1978. Growth, mortality, fecundity, biomass, and productivity of four lake populations of the proso- branch snail, Viviparus georgianus. Ecology 59:742-750. Buckingham, M. J. and D. E. Freed. 1976. Oxygen consump- tion in the prosobranch snail Viviparus eontectoides (Mollusca: Gastropoda) -II. Effects of temperature and pH. Comp. Biochem, Physiol. 53A:249-252. Burla, H. 1972. Die Abundanz von Anodonta, Unio pic- torum, Viviparus a tor. Lymnaea auricularia und Lym- naea ovata in Zurichsee, in Abhangigkeit von der Wasser- tiefe und zu verschiedenen Jahreszeiten. Vierteljahrs. Naturforsch. Ges, Zurich, 117:129-151. Clench, William J. 1962. a catalogue of the Viviparidae of North America with notes on the distribution of I 'i vipa rus georgianus Lea. Occ. Papers Moll. 2:261-287; 385-412. Davis, P. B. and H. K. Fenner. 1977. A simple technique for predicting the biomass of a prosobranch snail. Comp. Biochem. Physiol. 56A:127-128. de Bernardi, R., 0. Ravera. and B. Oregioni. 1976. Demo- graphic structure and biometrie characteristics of Vivi- parus ater Cristofori and Jan (Gasteropoda: Proso- branchia) from Lake Alserio (Northern Italy). Jour. Moll. Studies 42:310-318. Fitch, D. D. 1975. Oxygen consumption in the prosobranch snail Viviparus eontectoides (Mollusca: Gastropoda) -I. Effects of weight and activity. Comp. Biochem. Physiol 51A:815-820. 1976. Oxygen consumption in the prosobranch snail Viviparus eontectoides (Mollusca: Gastropoda) -III: Effects of light. Comp. Biochem. Physiol. 54A:253- 257. Fretter, V. and A. Graham. 1978. The Prosobranch Molluscs of Britain and Denmark, Part 3. Jour. Moll. Stiniirs. Suppl. 5:101-152. Harman, W. N. 1972. Benthic substrates: Their effect on fresh-water Mollusca. Ecology 53:271-276. Hyman, L. H. 1967. The Invertebrates: Vol VI. Mollusca /. McGraw-Hill Book Co.. N.Y. 1-792 p. Imlay, M. J., J. W. Arthur, B. J. Hailigan, and J. H. Stein- metz. 1981. Life cycle of the freshwater snail Campeloma decisum (Viviparidae) in the laboratory. The Nautilus 95:84-88. Jokinen, E. H. 19.S2. Cipaugojialudiua chinensis (Gastro- poda: Viviparidae) in North America, review and update. The Nautilus 96:89-95. Malniie. (' I; 1965 [)i persal of aquatic gastropods via the intestinal tract of water birds. Tk Nautilus 78:135-139. Pianka, E. R. 1974. Evolutionary Ecology. Harper & Row, Publishers, N.Y. viii, 1-356 p. Plinski. M., W. Lawacz, A. Stanczykowska, and E. Magnin. 1978. Etude quantitative et qualitative de la nourriture Vol. 99(2-3) April 29, 1985 THE NAUTILUS 53 des Viviparus malleolus (Reeve) (Gastropoda, Proso- branchia) dans deux lacs de la region de Montreal. Can. Jour. Zool. 56:272-279. Price, J. H. 1957. A study of the food habits of some Lake Erie fish. U. S. Fish and Wildlife Service Report No. 837, 1-105 p. Samochwalenko, T. and A. Stanczykowska. 1972. Fertility differentiation of two species of Viviparidae (Viviparus fasciatus Mueller and V. viviparus L.) in some en- vironments. Ekilogia Polska 20:479-492. Stanczykowska, A., E. Magnin, and A. Dumouchel. 1971. Etude de trois populations de Viviparus malleatus (Reeve) (Gastropoda, Prosobranchia) de la region de Montreal. I. Croissance, fecondite, biomasse et production annuelle. Can. Jour. Zool. 49:1431-1441. Stanczykowska, A., M. Plinski, and E. Magnin. 1972. Etude de trois populations de Viviparus malleatus (Reeve) (Gastropoda, Prosobranchia) de la region de Montreal. II. Etude qualitative et quantitative de la nourriture. Can. Jour. Zool, 50:1617-1624. Studier, E. H. and G. L. Pace. 1978. Oxygen consumption in the prosobranch snail Viviparus contectoides (Mollusca: Gastropoda) -IV. Effects of dissolved oxygen level, star- vation, density, symbiotic algae, substrate composition and osmotic pressure. Comp. Biochem. Physiol. 59A: 199-203. Thompson, D. 1973. Feeding ecology of diving ducks on Keokuk Pool, Mississippi River. Jour. Wildlife Manage- ment 37:367-381. Thompson, Fred G. 1985. Fresh Water Snails of Florida -A Manual for Identification. University of Florida Press. 94 pp., 193 figs. Vail, V. A. 1978. Seasonal reproductive patterns in 3 viviparid gastropods. Malacologia 17:73-97. Van Cleave, H. J. and L. G. Lederer. 1932. Studies on the life cycle of the snail Viviparus contectoides. Jour. Morph. 53:499-522. van der Schalie, H. 1965. Observations on the sex of t'umpeloma (Gastropoda: Viviparidae). Occ. Paps. Mus. Zool. Univ. Mich, 641:1-9. Young, M. R. 1975. The life cycle of six species of freshwater molluscs in the Worcester-Birmingham Canal. Proc. Malawi, Soc. Land. 41:533-548. MODERN METHODS USED TO AGE OCEANIC BIVALVES John W. Ropes National Marine Fisheries Service Northeast Fisheries Center Woods Hole Laboratory Woods Hole, MA 02543 ABSTRACT Modern techniques of thin- sectioning chondrophores and the preparation of acetate peels of sectioned valves are described that expose internal age/growth structures of two commercially important U.S. oceanic bivalves, Spisula and Arctica. The application of the methods in specific studies is reviewed. Verifica- tion of annual age marks was based on mark-recapture experiments and length frequency analyses for both species. New methods have been under investigation by the Northeast Fisheries Center since the mid-1970's for determining the age and growth characteristics of the Atlantic surf clam, Spisula solidissima (Dillwyn), and ocean quahog, Arctica islandica (Linne), bivalves that supply the bulk (79% in 1983) of the meats for clam pro- duction in the United States. Goals of the inves- tigation were that the methods produce accu- rate age determinations and be efficient, since about 1,500 shell specimens of each species may be taken during annual surveys. Age determina- tions on a timely basis are specifically needed for evaluations of age composition in assess- ment studies of the populations. Bands or rings form annually on the external valve surface of some bivalves, much like rings found in tree trunks, and have been used to determine age (Lutz and Rhoads 1980). Similar bands appear on the valves of young surf clams and ocean quahogs up to about 15 years of age, but with increasing age and size the earlier bands are often obliterated by erosion and later 54 THE NAUTILUS April 29, 1985 Vol. 99(2-3) bands become too crowded together at the valve margin for definite separation, even under microscopic examination. Confusing, unverifi- able and incomplete records are inevitable when such poorly defined shell features are used for age analysis. Thus, the use of such a general method for critical studies is precluded by the lack of accuracy in age determinations. Specific internal shell deposits that form an- nually have been found in other bivalves (Lutz and Rhoads 1980). They are considered to be relatively unaffected by external conditions causing erosion, but require care in exposing the deposits and critical microscopic examination. Therefore, methodologies were developed for examining such deposits in the shells of surf clams and ocean quahogs. Surf Clam Method Preliminary examinations of internal age/ growth features in the valves of surf clams were begun in 1975. Such examinations seemed justi- fied by the presence of thin, dark lines seen alternating with broader, white growth incre- ments in fossilized valves. Whole surf clam valves were cut in about one-half hour from the beginning (umbo) to the end of a clam's life at the valve margin using a diamond-impregnated saw blade (Fig. 1). The cut edges were then polished to remove saw marks and enhance the distinctive dark lines that were suspected to be age annuli. These lines curved down and back toward the umbo of a valve and became increas- ingly attenuated at the myostracal layer from a more prominent beginning beneath external bands. The myostracal layer separated inner and outer shell layers in these valves. The lines were validated as annual age marks by marking some surf clams for release and recovery at Chincoteague Inlet, VA (Ropes and Merrill 1970; Jones et al. 1978). Ambrose et al. (1980), Jones (1980, 1981a and b, 1983), Jones et al. (1983), and Arthur et al. (1983) report studies based on the annual periodicity of these lines in surf clams. Age determinations of whole valves required careful microscopic examination of the cut sur- faces. Holding the valve level and in focus under the microscope proved difficult and even more frustrating when trying to make growth meas- urements. In addition, the cutting, polishing and cc 3 s 8 VENTRAL DORSAL D DIRECTION OF CUT Hinge ligament — / /,> iif w hirh measures 24 mm ■ 1 7 mm. FIGS. 7 and 8. Favartia (Murexiella) leonae D'Attilio and Myers. Dorsal (7) and apertural (8) views of holotype. Dimensions 14.2 mm x 11.5 mm. SDNHM 81638. FIGS. 9 and 10. Favartia (Murexiella) leonae D'Attilio and Myers. Dorsal (9) and apertural (10) views of paratype H. Dimensions 13.1 mmxl0.6 mm. SDNHM 85109. FIG. 11. Camera lueida drawing of the protoconch oIF. (M.) leonae paratype D. SDNHM 85105. Greatly enlarged. Favartia (Murexiella) leonae, new species Figs. 7 tn 1 1 Shell broadly fusiform, shoulder angulate, spire moderately high, suture impressed. Proto- conch of holotype eroded; protoconch of para- type D with 2V4 dull white blunt, convex whorls; four to five postnuclear whorls. Aperture white. ovate; inner lip erect anteriorly. Anal sulcus directed to the left. Outer lip erect, crenulate, reflecting the exterior spiral sculpture. Siphonal canal broad above, narrowing and recurving distally, and weakly open. Siphonal fasciole with three scaly tubelike remnants of earlier canal terminations. Four varices on body whorl with Vol. 99(2-3) April 29, 1985 THE NAUTILUS 61 the intervarical areas unequal. Five varices on penultimate whorl. Two weak spiral cords on spire strongly developed only on the back slope of the varix. Five to seven spiral cords on body whorl, weakly defined between varices and strongly developed on receding portion of the varices. The first two to three cords developing into elongate spines on the varices except on the apertural varix where all cords are of equal size. On the final varix the moderately projecting cords connected by a continuous flange which abuts the penultimate whorl. Growth striae on the body whorl weakly developed. The leading side of the apertural flange with about four to seven well developed lamellae in the interspaces between the cords. Color: Pale rose shell with spines a much lighter hue. Occasionally (holotype) with a broad band of deep coral red. Type locality: Bolo Point, Okinawa, Ryukyu Islands, Japan from 55 meters depth. Paratypes from Okinawa, Ryukyu Islands, Japan, and from Bohol Straits, Philippine Islands. Dimensions: Holotype 14.2 mm in length 11.5 mm in width from Okinawa, Japan, (SDNHM 81638); paratype A, 14.4 mm x 10.2 mm from Okinawa, Japan (SDNHM 85102); paratype B, 10.7 mm x 8.6 mm from Okinawa, Japan (AMNH 213555); paratype C, 12.5 mm x 8.7 mm from Okinawa, Japan (SDNHM 85104); para- type D, 11.1 mmx7.8 mm from Bohol Straits, Philippine Islands, (SDNHM 85105); paratype E, 14.3 mmx 10.7 mm from Okinawa, Japan, (SDNHM 85106); paratype F, 14.2 mmx 11.0 mm from Okinawa, Japan, (SDNHM 85107); paratype G, 14.0 mmx 9.8 mm from Okinawa, Japan, (SDNHM 85108); paratype H, 13.1 mm xl0.6 mm from Okinawa, Japan, (SDNHM 85109); paratype I, 12.5 mmx 9.2 mm (SDNHM 85110). Etymology: Named for Leona Bellin, wife of Phillip Bellin, who first collected specimens of Favartia (Murexiella) leonae from Okinawa, Ryukyu Islands, Japan, used in this study. IHscnssudi: This species bears little <'<>m- parison with any of its congeners, with the ex- ception of an unnamed species which is more widespread and of a larger size, under study at the present time from the western Pacific. The lack of shoulder spines on the apertural varix is a consistent character in the specimens studied. Acknowledgments We wish to thank the following friends who contributed specimens for our study: Phillip Bellin of Okinawa, Japan; Robert Yin of La Jolla, California; Donald Pisor of San Diego, California; Edward Swoboda of Los Angeles, California; Robert Foster and Charles Glass of Santa Barbara, California. We are grateful to David K. Mulliner for the photography used in this paper and Dr. Hans Bertsch for his assistance with the Latin orthography. Dr. William K. Emerson (AMNH) kindly reviewed the manuscript. LITERATURE CITED Clench, W. J. and I. Perez Farfante. 1945. The genus .1/// ru- in the western Atlantic. Johnsonia l(17):l-56, pis. 1-28. D'Attilio, A. 1981. The rediscovery of Murex cirrosus Hinds, 1844. TheFestivus 13(4):46-51. figs. 1-8. DAttilio, A. and B. W. Myers. 1984. Redescription of Favar- tia cyclostoma (Sowerby, 1841) and selection of a lecto- type, with illustrations of some related species (Muricidae). TheFestivus 16 (11):116-122, figs. 1-12. Hinds, R. B. 1844. The Zoology of the Voyage of HMS Sulphur . . ., vol. II, 72 pp., 21 pis. Jousseaume. F. 1880. Division methodique de la famille des Purpurides. Le Natural iste 42:335-36. Radwin, G. E. and A. DAttilio. 1971. Muricacean supraspe- cific taxonomy based on the shell and the radula. The Echo 4:55-67, 23 figs. Rafinesque, C. S. 1815. Analyse de la nature 8.0 mm shell length) and juvenile (~2. 5-8.0 mm shell length) clams were measured for shell length by vernier calipers (accuracy, ±0.05 mm). Estimates of "larval" (veliger) density in each sample were made by analyzing the sediment fractions that were <2.5 mm from each replicate. Statistical Treatment of Data Preference experiments were analyzed by one-way analysis of variance (ANOVA) (Steel and Torrie, 1960) at each observation period and for each sediment pairing. For each pair of sediments, three possible outcomes were com- pared: (1) clams would reside in sediment A, (2) clams would reside in sediment B, or (3) clams would remain in the region of the demarcation between sediment A and sediment B. If a significant difference existed by the ANOVA F-test (a = 0.05), Duncan's Multiple Range Test was performed to determine which group(s) were significantly different (Steel and Torrie, 1960). Results of Corbicula densities observed in the field in coarse and fine sediments were analyzed by the student's t-test. Results Laboratory Preference Study Corbicula were found to prefer any substrate (fine sand, organically enriched fine sand, or coarse sand) over no substrate at all (Table 2). Clams were observed to move rapidly into sedi- ments. After 1 hr, 70-80% of the clams were buried in the sediments offered. By the third Vol. 99(2-3) April 29, 1985 THE NAUTILUS 69 TABLE 2. Analyses of variance for Corbicula sediment preference of fine sand versus no substrate, organically enriched fine sand versus no substrate, and coarse sand versus no substrate conducted at the Ecosystem Simulation Laboratory and Glen Lyn field laboratory. Means with the same letter are not significantly different (o = 0.05) using Duncan's Multiple Range Test. Substrate % Residence at Time Site F-ratio 1 hr (p-value) F-ratio' Day 1 (p-value) Days 3-7 ESL Fine No Substrate Uncommitted 71. 1+31. 8a 4.4±8.8 25.5+21.8 97.8±6.7a 0±0b 2.2±6.7a 100.0+0 0±0 0 + 0 Organic- No Substrate Uncommitted 82. 2+27. 3a 4.4±8.8b 13. 4+27. 9b 97.8±6.7a 0±0b 2.2±6.7 100. 0±0 0 + 0 0 + 0 Coarse No Substrate Uncommitted 82.2127.0^ 8.9±20.2 8.9±14.5 97.8+6.7a 2.2+6.7b 0±0b 100. 0±0 0 + 0 0 + 0 Glen Lyn Fine No Substrate Uncommitted 46. 7+46. 9a 2.2+6.2b 51. 2+46. 9a 100. 0±0 0±0 0±0 100. 0±0 0 + 0 0±0 Organic No Substrate Uncommitted 62.2±27.2a 2.2±6.7b 35.1±30.0a 100. 0±0 0±0 0+0 100.0+0 0 + 0 0 + 0 Coarse No Substrate Uncommitted 46.7±24.5a 6.7+10.0 46. 6+21. 9a 82.2±27.2a "4.4 + 8.8b 13.4+12.7 100. 0±0 0±0 0±0 'All clams resided in the substrate from Day 3 to Day 7. Analyses of variance are not quoted since the data are unsuitable for this statistical method. 2Uncommitted clams were designated as those that did not move from the line of demarcation be- tween sediments. day, 100% of the clams were buried in all sedi- ments, and none remained exposed (Table 2). Clams consistently preferred fine sand or or- ganically enriched fine sand when coarse sand was the alternative choice (Table 3). The choice of fine sands was significant by Day 3 (Table 3), although, for fine sand alone, the choice was made sooner (on Day 1; Table 3). When clams were offered the choice of organi- cally enriched fine sand vs fine sand, the prefer- ence pattern was less distinct than for either of these sediments vs no substrate or coarse sand (Table 3). Ultimately, fine sand was significantly preferred over organically enriched fine sand (Days 6 and 7; Table 3). Field-Laboratory Preference Study Results of these preference trials were similar to experiments conducted at the ESL. Any substrate (e.g., fine sand, organically enriched fine sand, and coarse sand) was significantly preferred over no substrate at all (Table 4). By Day 3, all clams were buried in fine sand, organi- cally enriched fine sand, and coarse sand when no substrate was the alternative (Table 4). Clams did not prefer coarse sand when offered fine or organically enriched fine sand; however, fine sand was significantly preferred sooner (Day 1; Table 4) than organically enriched fine sand (Day 3; Table 4). By Day 7, 78% of the clams resided in fine sand when coarse sand was the alternative, and 71% resided in organically enriched fine sand when coarse sand was the alternative (Table 4). Preference trials of fine vs organically enriched fine sand showed clams preferred fine sand. By Day 5, 60% of the clams resided in fine sand substrate (Table 4). Field Sampling The density of Corbicula was two to three times greater in fine sand (75% of the sediment was in the 0.35-0.60 mm size range) than coarse 70 THE NAUTILUS April 29, 1985 Vol. 99(2-3) TABLE 3. Analyses of variance and percent residence for Corbicula sediment preference experiments at the Ecosystem Simulation Laboratory. Means with the same letter are not significantly different (a = 0.05) using Duncan's Multiple Range Test. % Residence at Time Substrate 1 hr Day 1 Day 3 Day 5 Day 7 Organic- 40.0±30.0 51. 1138. 8a 64. 4123. 4a 66. 7120. 7a 76.7115. Ia Coarse 26.7130.0 a,b 28.9124.5 21.1117.8 30. 0120. 9b 20. 011 7. 9b Uncommitted 33.3±30.0 20.0121.1 14.4±16.3b 3.318.2C 3.318.2° Fine 32.2127.9 62. 216. 73 63. 3136. 7a 70.0116. 7a 70. 0127. 6a Coarse 27.8120.0 24. 4116. 7b 6.7110.3 13. 3116. 3b 23. 3129. 4b Uncommitted 47.8124.5 13. 3117. 3b 30.3130. 3a' b 16.7t8.1b 6.7116.3 Fine 24.4126.0 64. 1127. 3a 37.0127.3 70.0135. 2a 73. 3130. la Organic 47.7120.0 31. 9114. 5b 37.0127. 3 13. 3116. 3b 23. 3126. 6b Uncommitted 28.9128.4 14. 1114. 1C 25.9123.3 16.7119.7 3.3l8.2b F (and in parentheses, p-values) were 0.44 (0.6464); 2.71 (0.0866); 11.71 (0.0009); 19.50 (0.001); 43.37 (0.0001) for time 1 hr through Day 7. F (and in parentheses, p-values) were 1.67 (0.2085); 28.50 (0.0001); 6.15 (0.0112); 29.67 (0.0001); 10.25 (0.0016) for time 1 hr through Day 7. F (and in parentheses, p-values) were 1.98 (0.1605); 11.90 (0.0030); 0.48 (0.6245); 9.61 (0.0021); 13.93 (0.0004) for time 1 hr through Day 7. TABLE 4. Analyses of variance and percent residence for Corbicula sediment preference experiments at Glen Lyn. Means with the same letter are not' significantly different (a = 0.05) using Duncan's Multiple Range Test. % Residence at Time Substrate 1 hr Day 1 Day 3 Day 5 Day 7 Organic a,b 35.6127.9 ' 44. 4129. 6a 53. 3130. 0a 60. 0122. 4a 71. 1117. 63 Coarse 15. 6126. 0b a,b 40.0133.1 ' 37. 8127. 2a 40. 0122. 4b 15. 6113. 3b Uncommitted 48. 9130. 2a 15. 6119. 4b 8.9120.2 010 4.4t8.8b Fine 26. 7117. 3b 60. 7120. 0a 71. 1120. 3a 69.6128. 5a 77.8127. 3a Coarse 8.9110.5C 24. 4119. 4b / 8.9tl4.5b 24. 4121. 9b 22.9121. lb 22. 2127. 3b Uncommitted 64. 4113. 3a 4.418.8C 7.4114. lb o.oc Fine 20. 0134. 6a 40.0117.3 46. 7124. 53 60.0114. I3 62. 2123. 3a Organic 17.8123. 3a 40.0124.5 44. 4124. 0a 37. 8115. 6b 33.3122.4 Uncommitted 62. 2139. 3b 20.0122.4 13. 3122. 4b 2.216.7° 4.4113.3° F (and in parentheses, p-values) were 3.24 (0.050); 2.78 (0.0825); 6.68 (0.0049); 25.20 (0.0001); 60.78 (0.0001) for time 1 hr through Day 7. 2F (and in parentheses, p-values) were 36.91 (0.0001); 24.4 (0.0001); 32.69 (0.0001); 19.45 (0.0001); 29.10 (0.0001) for time 1 hr through Day 7. F (and in parentheses, p-values) were 5.15 (0.0138); 2.57 (0.0973); 5.59 (0.0102); 46.91 (0.0001); 18.44 (0.0001) for time 1 hr through Day 7. Vol. 99(2-3) April 29, 1985 THE NAUTILUS 71 sand/gravel substrate (90% of the sediment was in the 4.50-36.00 mm size range) in the New River. Sediment composition of the December 18 samples is summarized in Figure 2. The den- sities of adult and juvenile Corbicula were ap- proximately the same for both samples in the respective sediments (Table 5). After combining the results of both September 9 and December 18 samples, a t-test indicated that the densities of the clams were significantly greater in the finer sand substrate than in coarse sand/gravel. These results are consistent and supportive of the laboratory and field-laboratory preference experiments. Discussion Sediment preferences of Corbicula were con- sistent in both laboratory and field-laboratory experiments. Although some temporal differ- ences existed for some comparisons, relative to where the experiment was performed (e.g., fine sand vs coarse sand, and fine sand vs organi- cally enriched sand), the preferences were ulti- mately identical (i.e., fine sand was preferred i o >- CO o 5 o o z LU O DC LU a. z < 30 20 ja .H -S JS am Coarse Sand /Gravel Fine JOi L <0.10 0.11 0.26- 0.25 0.35 0 36 0.50 0.51 0.60 0 61 0.70 071- 1.50 151- 2.50 2.51 4 50 4.51- 9 51 18 01 9.50 18.00 3600 PARTICLE SIZE |mm| FIG. 2. Mean percent composition by weight of coarse sand/gravel samples and fine sand samples from the New River taken by Surber sampling for Corbicula densities. TABLE 5. Densities of larval (^1 mm), juvenile (1.0 to 8.0 mm) and adult Corbicula (>8.0 mm) within the New River at McCoy, Virginia. Collection Date Sediment Type Larval Density t-test ( individuals/m2 ) {p-value) Juvenile/Adult Density (individuals/m2 t-test Shell length (p-value) (Means±SD) t-test (p-value) 9 Sept 1984 Fine sand 3 — Coarse 3 -- Sand/ gravel 18 Dec 1984 Fine sand 3 14.3 ± 6.51 Coarse 3 14.37 ± 16.38 sand/ gravel Combined Fine sand 6 — Coarse 6 sand/ gravel 398 1 ± 376.6 10 28 * 2 34 123 139 8 ± 59.9 1 (0 173 3580) 10 52 t 3 83 39 0 (0 4091 6831) 505 72 + 67.2 11 08 + 3 16 141 215 2 i 32.3 6 (0 750 0084) 11 69 i 2 46 50 1 (0 3237 1871) 451 9 ± 24.90 10 71 + 2 83 264 177 5 ± 59.6 2 (0 625 0425) 11 3 5 + 2 •• B9 1 (0 799 0729) 72 THE NAUTILUS April 29, 1985 Vol. 99(2-3) for the aforementioned comparisons). Thus, it was possible to rank the observed experimental- ly identified preferences to predict the sites/ substrates of varying densities of clams located in the field. The preferences observed in these studies were in the following descending order: fine sand - organically enriched fine sand - coarse sand - no substrate. The field sampling, which found clams to be significantly denser in the fine sand than coarse sand/gravel under similar environmental conditions of current, temperature, light, and season, corroborated our predictions in this study. The importance of sediment to population dynamics and success of Corbicula invasion has been previously emphasized by several investi- gators. Eng(1979) discussed the use of incrusta- ceans along the Delta- Mendota concrete canal by Corbicula as a nursery zone and refuge for larvae and small juveniles. Sickel and Burbank (1974) investigated preferences of newly re- leased juveniles for substrates and found coarse sand was preferred over mud (potentially oxygen-limiting) or bare concrete (ecologically barren surface). McMahon (1983) suggested that flourishing Corbicula populations in streams that are canalized may optimize the environ- ment for this species by eliminating the reduc- ing environments of mud and silt under fast flowing conditions. The importance of thermal inputs from power plants and other industrial installations has been documented previously by several investigators (Rodgers et al., 1977; McMahon, 1977; Scott- Wasilk et al, 1983). Graney et al. (1980) surveyed Corbicula popula- tions at the Glen Lyn Power Plant in thermally influenced and uninfluenced stations with vari- ous substrate compositions and concluded that thermal discharges had a greater influence upon clam survivorship and density than substrate composition. It is important to note that ther- mal effluents allow clams to sustain reproducing populations over the winter where they would otherwise not occur (Graney et al., 1980; Scott- Wasilk et al., 1983; McMahon, 1982). Corbicula has continued to invade new habi- tats in North America and is now found in near- ly every state in the continental United States (McMahon, 1982). The ability of Corbicula to utilize a wide variety of substrates, from fine sand to gravel (which Corbicula finds inhabit- able), has enhanced its success. However, this study suggests that rivers with fine, well oxy- genated sand substrates would be optimal for establishment of Corbicula populations in newly colonized sites. LITERATURE CITED Aldridge, D. W. and R. F. McMahon. 1978. Growth, fecund- ity, and bioenergetics in a natural population of the fresh- water clam, Corbicula manileyisis Phillippi, from North Central Texas. Jour. Mollusc. Studies 44:49-70. Cherry, D. S., R. L. Roy, R. A. Lechleitner, P. A. Dunhardt, G. T. Peters and J. Cairns, Jr. In Press. Corbicula invasion in the New River: fouling and control measures at the Celco Plant, Virginia. In Proceedings of the 1983 Second International Corbicula Symposium. Little Rock, Arkansas. Clark, J. R., J. H. Rodgers, Jr., K. L. Dickson and J. Cairns, Jr. 1980. Using artificial streams to evaluate perturbation effects on aufwuchs structure and function. Water Resourc. Bull 16:100-104. Dudgeon, D. 1980. A comparative study of the Corbiculidae of Southern China. In B. Morton (editor) The Malaco- fauna of Hong Kong and Southern China. Hong Kong University Press, Hong Kong. p. 37-60. Eng, L. L. 1979. Population dynamics of the Asiatic clam, Corbicula fluminea (Miiller), in the concrete-lined Delta- Mendota canal of central California. In J. C. Britton (editor) Proceedings of the First International Corbicula Symposium. Texas Christian University, Fort Worth. Texas, p. 39-68. Graney, R. L., D. S. Cherry, J. H. Rodgers, Jr. and J. Cairns, Jr. 1980. The influence of thermal discharges and sub- strate composition on the population structure and distri- bution of the Asiatic clam, Corbicula fluminea, in the New River, Virginia. The Nautilus 94:130-135. Home, F. R. and S. Mcintosh. 1979. Factors influencing distribution of mussels in the Blanco River of Central Texas. The Nautilus 93:119-133. McMahon, R. F. 1977. Shell size-frequency distribution of Corbicula manilensis Philippi from a clam-foaled steam condenser. The Nautilus 91:54-59. 1979. Response to temperature and hypoxia in the oxygen consumption of the introduced Asiatic fresh- water clam Corbicula fluminea (Muller). Camp. Biochem. Physiol. 63A:383-388. 1982. The occurrence and spread of the intro- duced Asiatic freshwater clam, Corbicula fluminea (Muller), in North America: 1924-1982. The Nautilus 96:134-141. 1983. Ecology of the invasive pest bivalve Corbicula. In W. D. Russel-Hunter (editor) Tin Mollusca: Ecology. Vol. 6. Academic Press, Inc., New York. p. 505-562. Rodgers. J. H.. Jr.. D. S. Cherry, J. R. Clark. K. L. Dickson and J. Cairns, Jr. 1977. The invasion of Asiatic clam, Corbicula manilensis. in the New River. Virginia Tin Nautilus 91:43-46. Rodgers, J. H.. Jr., D. S. Cherry, K. L. Dickson and J. Cairns, Jr. 1979. Invasion, population dynamics and ele- Vol. 99(2-3) April 29, 1985 THE NAUTILUS 73 mental accumulation of Corbicula fluminea in the New River at Glen Lyn, Virginia. In J. C. Britton (editor) Proceedings of the First International Corbicula Sympo- sium. Texas Christian University, Fort Worth, Texas, pp. 99-110. Scott-Wasilk, J., G. G. Downing and J. S. Leitzow. 1983. Occurrence of the Asiatic clam Corbicula fluminea in the Maumee River and Western Lake Erie. Journ. Great Lakes Res. 9:9-13. Sickel, J. B. and W. D. Burbank. 1974. Bottom substratum preference of Corbicula manilensis (Pelecypoda) in the Altamoha River, Georgia. Assoc. Southeastern Biol. Bull. 21:84. Steel, R. G. D. and J. H. Torrie. 1960. Principles and Pro- cedures of Statistics with Special References to the Biological Sciences. McGraw-Hill, New York. 481 p. A WEST INDIAN COLUMBELLID NEW TO THE GENUS STEIRONEPION C. John Finlay 1024 Daytona Dr. NE Palm Bay, FL 32905 ABSTRACT In 1850 C. B. Adams described Pleurotoma maculata from Jamaica. Subse- quent beach specimens from Varadero Beach, Cuba, and the Bahamas, as well as examples from dredged sand at Marianao, Havana, Cuba (described as Turri- jaumelia jaumei Sarasila, 1975), further extend, the known range. A morphological assessment would suggest that the species be placed in the columbellid genus Steironepion, thus adding a third species to that genus from the Caribbean marine basin, and making Turrijaumelia a subjective synonym of Steironepion. In "Poeyana", published under the auspices of the Institute of Zoology, Cuban Academy of Sciences, Havana, Cuba, Dr. Hortensia Sarasiia described a new turrid gastropod, erecting the new genus and species Turrijaumelia jaumei. Although the type specimen of Pleurotoma maculata Adams, 1850, figured by Clench and Turner, is a worn specimen, there seems little doubt that T. jaumei should be synonomized with that taxon. None of the Cuban or Baha- maian specimens were live-taken. Perusal of George Radwin's comprehensive treatment of the family Columbellidae in the western Atlantic, would suggest adding this species to the genus Steironepion which now contains the Caribbean species S. minor (C. B. Adams, 1845) and S. moniliferum Sowerby, 1844). Placement of this columbellid in the Tur- ridae by Adams and Sarasiia may have resulted in their considering the rather swollen anal sinus as a turrid notch. Since C. B. Adams' description of this species is very brief, it is deemed desirable to translate and reproduce below Dr. Sarasiia's detailed description of this very attractive little shell. Turrijaumelia, new genus Description: Shells small, slender, not fragile but delicate. Large nuclear whorls, smooth and bulbous, the post nuclear whorls are character- ized by angular perimeters and well defined sutures. Sculpture reticulated, formed by thin axial ribs, crossed by smooth spiral cords, form- ing sharp rib projections on the lower half of the whorls. The spaces between the reticulated sculpture reveal numerous microscopic axial threads. Aperture narrow, sigmoidal, with the anal channel somewhat enlarged. Outer lip with slight stromboid notch, showing interior liration and the anterior canal recurved backwards and to the right. Genotype - Turrijaumelia jaumei, new species Discussion: Among the many genera of the Turridae, we have not been able to find one fit- ting our lot; the bulbous and smooth nuclear whorls, the angular periphery of the post nuclear whorls, the smooth spiral cords, the rib projections and the peculiar microscopic axial threads in the reticulated spaces, give us what 74 THE NAUTILUS April 29, 1985 Vol. 99(2-3) we believe to be sufficient characteristics to establish the new genus Turrijaumelia. Turrijaumelia jaumei, new species Description: Shell small, elongated and graceful, of delicate and vitrious appearance; nuclear whorls two, large bulbous and smooth, followed by 4-4.25 post-nuclear whorls, well defined suture and angular periphery. The last whorl narrows and forms the siphon canal com- pleting the graceful appearance of the species. Sculpture consisting of marked narrow ribs, more or less 12 on the last whorl, higher on the lower half of the whorls and more slender at the base of the shell, crossed by smooth spiral cords, well separated. At the top half of the whorls, which are strongly sloped, there are 3 or 4 spiral cords of the same width, separated by a space more or less the same width as the width of these cords. The spiral cords on the lower half of the whorls are wider and more separated from one another, the first extends from the middle line of each whorl, and these in turn form the sharp rib projections which point upwards; three of these spiral cords are observed on the last whorl. At the base of the last whorl are two spiral cords, the first of which may have slender projections, on the second these may appear in- stead as small nodules. On the siphon canal are two spiral cords of small nodules, followed by three narrow cordlets. In the translucent spaces of the reticulated area, which on the lower half of the whorls, are large and rectangular, are microscopic axial threads, straight and parallel, separated from one another by spaces more or less the same as their width; these axial threads reach the sides and surface of the ribs, and at the point appear slightly curved. On the siphon canal the spiral sculpture is crossed by microscopic axial lines. The outer lip of the aperture reveals four den- ticulations on the inside border formed by the termination of the lirations, the two upper ones being clearly visible. The general color of the shell is white, a few brown spots are observed on the upper part of the spiral cords where the whorls slope downward; the base of the last whorl may be yellowish, and a touch of brown may appear on the last rib. On the nuclear whorls, at the beginning of the suture, there is generally a brownish spot. The measurements given for the width of the shells, are without consideration to the sculptural projections. Width Width Length (greatest) (narrowest) Holotype 4 mm 1.75 mm 1.70 mm Marianao, Habana Paratype 4 mm 1.60 mm 1.50 mm Marianao, Habana Paratype 4.1 mm 1.50 mm 1.40 mm Marianao, Habana The type shells form part of a lot of 19 specimens, dredged from sand at a depth of ap- proximately 20 metres, were taken offshore at Marianao, Habana, and collected by Sr. Primi- tivo Borro. Another three specimens were found by the author in sand from the same location. Type catalog No. 36 (holotype) and 37 and 38 (paratypes.) Steironepion maculatum (C. B. Adams, 1850) (Figs. 1. 2) Synonomy - 1850 Pleurotoma macuiata C. B. Adams. 1850, Contribu- tions to Conchology, No. 4, p. 62 (Jamaica); 1950 Clench and Turner, Occasional Papers on Mollusks, vol. 1, No. 15, p. 305, pi. 29, fig. 3 (holotype) 1887 Pleurotoma (DriUia) maculata Verkruzen. Paetel, Catalog der Conchylien-Sammlung von Fr Paetel. vol. 1. p. 56 (Jamaica), [listing only]. 1975 Turrijaumelia jaumei Sarasua, Poeyana (Havana), No. 140, pp. 12-15, (20 metres, off Marianao, Habana, Cuba). Records -BAHAMAS: West Beach, Staniel Cay, Exhumas, Dieter Cosman collector, 1966. CUBA: Varadero Beach, North coast of Cuba (drift), C. John Finlay collector, 1952; Marianao, Habana, Primitivo Borro and Hortensia Sarasua, from sand dredged in 20 metres. JAMAICA: C. B. Adams, 1850; Paetel, 1887. Genus Steironepion Pilsbry and Lowe, 1932 Synonomy - 1932 Steironepion Pilsbry and Lowe, Proc. Acad. Sat. See Philadelphia, vol. 84, p. 57 (type by original designation: Mangelia melanosticta Pilsbry and Lowe, 1932). 1943 Psarostola Render, Proc U. S. Nat. Mus., vol. 93, No. 3161, p. 198 (type by original designation: Columbella monilifera Sowerby, 1844). 1975 Turrijaumelia Sarasua, Poeyana (Havana), No. 140, pp. 12-15, (type by monotypy: T. jaume) Sarasua. 1975) This interesting group of small columbellids with a reticulated or beaded sculpture and a strong anal notch has been placed in the turrids by many authors until Rehder (1943), Keen (1971) and Radwin (1977) showed its columbellid affinities both in shell and radular characters. Curiously, Sowerby (1844), Duclos (1848 and Vol. 99(2-3) April 29, 1985 THE NAUTILUS 75 FIGS. 1, 2. Steironepion maeulatum (C. B. Adams, 1850). Beach drift, Varadero Beach, north coast of Cuba, 1952, 4.5 mm, C. J. Finlay collector. Try on (1883) also placed Steironepion rnonili- ferum (Sowerby, 1844) in the Columbellidae. Radwin (1977) removed Steironepion from the genus Nassarina and considered it a full genus, a view in which I concur. Acknowledgments Thanks go to Dr. R. Tucker Abbott for his en- couragement in writing this paper and for his critical reading of the manuscript. I am also in- debted to Mrs. Virginia 0. Maes for reviewing a preliminary outline of the paper. To Mr. Paul Mikkelsen many thanks are due for the fine photographs of the Varadero Beach specimens. LITERATURE CITED Clench, W. J. and Turner. R. D., 1950. The Western Atlantic Marine Mollusks described by C. B. Adams. Occasional Papers on Mollusks, Vol. 1, June 26, 1950. Sarasua, H., 1975. New Genera, Subgenera and Species of Neogastropod Marine Mollusks, Poeyana. Academy of Sciences, Habana, Cuba. No. 140, pp. 12-15, January 17. 1975. Radwin, G. E., 1977. The Family Columbellidae in the West- ern Atlantic, Part Ha. The Veliger, Vol. 20, No. 2, pp. 119-133. ACTIVITY PATTERNS AND HOMING IN TWO INTERTIDAL LIMPETS, JORDAN GULF OF AQABA Neil C. Hulings Marine Science Station P.O. Box 570 Aqaba, Jordan ABSTRACT The foraging and homing behavior of Cellana radiata (Born) and Siphonaria laciniosa (Linne) occurring in the rocky intertidal zone has been determined. C. radiata, a prosobranch, forages when submerged during day and night, is a tem- porary homer and migrates up and down with changes in sea level. S. laciniosa, a pulmonale, forages when submerged but only after sunset and is a rigid homer. Homing behavior in relation to desiccation and density dispersion are discussed. Migration, intra- and interspecific competition are also discussed. Activity patterns, including foraging and homing of many prosobranch and pulmonale limpets, have been investigated for many years. The patterns, especially foraging or feeding ex- cursions, have been found to be quite variable as to when and under what conditions they occur. Homing has also been found to be variable and various reasons have been proposed for such 76 THE NAUTILUS April 29, 1985 Vol. 99(2-3) behavior including reduction of desiccation, bet- ter utilization of resources, especially food and protection from predators (Underwood, 1979; Branch, 1981; Garrity and Levings, 1983 and in- cluded references). There are only two limpets found in the rocky intertidal zone along the coast of Jordan, the patellid Cellana radiata (Born, 1778) (alias C. rota (Gmelin, 1791)) and the pulmonate Sipho- naria laciniosa Linne, 1758 (alias S. kurra- cheensis Reeve, 1856). C. radiata is the larger of the two species, reaching lengths of up to 48 mm, whereas S. laciniosa rarely exceeds 20 mm. Both species occur in the midlittoral zone of Stephenson and Stephenson (1949) within which Safriel and Lipkin (1964) designated a higher chthamalid zone and a lower Tetraclita zone. C. radiata has a wide vertical distribution, ranging from above the chthamalid zone to below the Tetraclita zone and occurs on vertical to horizontal surfaces of boulders, pebbles and various types of slab substrata. S. laciniosa, in contrast, is mostly restricted to near the chtha- malid zone (within the range of C radiata) and occurs more commonly on horizontal, soft, cal- careous substrata rather than on hard sub- strata. Both limpets are grazers, feeding on microalgae. Prior to the present report, nothing was known of the foraging and homing behavior of Cellana radiata and Siphonaria laciniosa in the Red Sea. Voucher specimens of both species are on deposit in the U.S. National Museum of Natural History and in the reference collection of the Marine Science Station in Aqaba, Jordan. The Rocky Intertidal The rocky intertidal zone along the coast of Jordan is quite variable, ranging from granitic boulders to multicolored pebble beaches to low profile slab or platform beaches. The latter may be sandstone, gravel-pebble conglomerate, beach rock or fossil coral reef consisting of eroded coral heads in a cemented calcareous matrix. Wave action on slab beaches is usually minimal as they are protected by outer reef crests or occur on the leeward side of land pro- jections. The mixed tides have a spring range of about 1 m and a neap range of around 50 cm (Fishelson, 1973; Hulings, unpublished data). The diurnal inequality averages 4.2 cm for the high tides, and 4.7 cm for the lows (Hulings, unpublished data). Fluctuations in sea level of up to 1 m occur. From December through May, the sea level is the highest; from July through September-October it is the lowest (Fishelson, 1973; Hulings, unpublished data). From late September through November there is a gradual rise in sea level, and from late May through June there is a gradual lowering. There is no river discharge into the Gulf of Aqaba and this in combination with low rainfall (23 mm/yr, Morcos, 1970), high evaporation (up to 4 m/yr, Anati, 1976), prevailing N-NNE, hot and dry winds (Hulings, 1979) results in a con- stant salinity of 40.5 to 41.5 ppt (Paldor and Anati, 1979). The mean air temperature has a wide range, from about 16°C in January to 32°C in August (Jordan Meterological Department), while water temperature has a much narrower range, from 20°C in February to 27°C, in August- September (Morcos, 1970). Methods and Materials Most of the data on the activity and homing of Cellana radiata were obtained from specimens living on a low profile calcareous fossil reef plat- form in the midlittoral zone above the Tetraclita zone; additional data on C. radiata were ob- tained on specimens occurring on large and rela- tively smooth granitic pebbles. The shells and the home area were color-coded, using either enamel paint or fingernail polish. Three color- coded groups of 15 specimens, each occurring on the calcareous substratum and averaging 30.1 mm in length, were observed continuously from 6 October through 7 November 1983 and periodically through 15 February 1984. The 19 color-coded C. radiata occurring on the granitic pebbles averaged 24.0 mm in length and were observed from 6 October through 7 November 1983. I ii order to obtain informal ion on I lie overall movement of Cellana radiata, 55 individuals (average length of 25.4 mm) within a 1 m2 area were painted and then observed from 11 September through 7 November 1983 on a daily basis and periodically through mid-June 1984. A 1 m2 metal frame divided into 10 x 10 cm quad- rates was put in the same place during low tide, Vol. 99(2-3) April 29, 1985 THE NAUTILUS 77 the time of observation, and removed after each observation. For Siphonaria laciniosa, a total of 90 indi- viduals, averaging 15.2 mm in length, were color-coded and observed from 10 September through 9 November 1983 and periodically through mid-July 1984. The 90 individuals con- sisted of four separate populations, two of which consisted of 12 and 34 individuals occurring on eroded coral reef heads having a very irregular surface; 25 specimens occurred on a relatively smooth, cemented, calcareous matrix, and a fourth population of 16 individuals occurred on beachrock of cemented granule-sized grains. Concurrent observations were conducted on six specimens averaging 13.2 mm in length kept submerged in an aquarium with running sea water. Observations on Cellana radiata and Sipho- naria laciniosa were made during day and night, spring and neap tides, flooding and ebb- ing tides and during complete submergence and emergence as well as combinations of the above. Results Cellana radiata became active soon after sub- mergence and returned from foraging during the period from maximum flood tide to just before or after emergence. Movement during foraging was not continuous and the distance of the excursions varied from 3 to 35 cm. The direction of movement varied from predomi- nately unidirectional to up to 45° from the main direction. Limited data indicates that the return is along the outgoing path. There were individ- uals that did not forage during consecutive cycles of submergence. During emergence, C. radiata remained inactive. The periods of forag- ing activity and inactivity occurred equally during day and night. The homing behavior of Cellana radiata was extremely variable. Among three groups each of 15 color-coded specimens living on relatively flat calcareous substrata 38% were initially non- homers. For the homers, the percent of the in- dividuals returning to the original home decreased to 4% over a period of 33 days. Simi- lar decreases in homing were noted among other marked specimens on the large and smooth granitic pebbles. The decrease in the percent of homers was not, however, constant. Fluctuations in the percent occurred because of the return of some individuals to the original home after one or more days of absence. Many of those that left the original home subsequently established one or more new homes. In cases where the home was occupied by another in- dividual, the homer returned to as close as possi- ble to the home but did not dislodge the new occupant. The average number of days that Cellana radiata occupied the original home was 11 and ranged from 1 to 22. Those specimens occupying a new home did so for an average of 3 days (range, 2 to 7). The homing scar of Cellana radiata on a cal- careous substratum was either entirely greenish in color or greenish with the periphery tan to white. The latter color pattern appeared to be characteristic of those individuals homing for extended periods. The color patterns disap- peared, however, a few days after the home was vacated. No depressions, excavations or other physical markings in the scars were seen. Scars were absent on the hard granitic pebbles. On the soft calcareous substratum scars from C. radiata were as small as 11.0 mm in length. The observations of the 55 marked Cellana radiata within the 1 m2 area revealed that over a period of 55 days the number decreased from 55 to 6. The number leaving the area was offset, however, by immigrants entering the same area. The exodus was gradual as was the im- migration into the area. The result was that the density in the m2 area remained relatively con- stant, averaging 58 individuals/m2 over a period of 55 days. The direction of movement of 55% of the marked Cellana radiata from the area was toward the high water mark or vertical while 36% were to either side of the area and approx- imately parallel to the shoreline. The remaining 8% moved seaward or vertically downward. A similar pattern of upward and/or lateral move- ment was noted among non-homing individuals marked for homing observations. Homing con- tinued among some individuals while migration occurred in others. There was no obvious direc- tional movement of the immigrants into the m2 area although there appeared to be net move- ment toward the high water mark. During May and June 1984, a general pattern of seaward 78 THE NAUTILUS April 29, 1985 Vol. 99(2-3) migration was noted among remnants of the originally marked populations. The foraging activity of Siphonaria laciniosa was restricted when they were submerged and was begun only after sunset. Activity occurred either during flooding or ebbing tides but only as long as the individuals were submerged and usually within a minimum of 30 minutes after sunset, but more commonly 45 to 60 minutes after sunset. Excursions of up to 20 cm and averaging 54 minutes in length (range, 25 to 100 minutes) occurred. Movement was not con- tinuous during the foraging excursions. The return to the home locality was usually along the outgoing path. The number of Siphonaria laciniosa within a particular population foraging at a particular time was extremely variable. Rarely did all the individuals of a given population forage during one period of suitable conditions. In some cases, there was no foraging among any of the indi- viduals of a given population on a particular oc- casion. There appeared, however, to be almost total foraging activity among all individuals within a population on successive periods of suitable conditions. Without exception, all Siphonaria laciniosa homed following the foraging excursions, in- cluding specimens continually submerged in an aquarium. Furthermore, the homing was found to be rigid in that it was continuous over the period from 10 September through 9 November 1983. An exception was in three specimens which moved to a new home but subsequently remained at the new home. Observations through mid- July 1984 revealed all of the originally observed S. laciniosa occupying the same homes. The scar of Siphonaria laciniosa occurring on calcareous substrata was white in the center and green on the periphery. The coloration disap- peared, however, within a few days after the home was no longer occupied. The scar was usually a depression, part of which was com- monly surrounded by a ridge. The surface of the depression tended to be smoother than the sur- rounding substratum. The depressions were generally more common among large than small specimens. Among both large and small individ- uals, the edge of the shell conformed to the con- figuration of the substratum. Scars with the coloration pattern and depres- sion were absent among Siphonaria laciniosa occurring on hard, non-calcareous substrata such as granular beach-rock and pebbles. Among these homing individuals, the edge of the shell conformed to the surface configuration of the substratum regardless of the irregularity. Discussion The patterns of foraging activity and homing in the two rocky intertidal limpets along the coast of Jordan are very different. The patellid, Cellana radiata, is a temporary or non-rigid homer, as well as being migratory. In addition, it is active both day and night but forages only when submerged. In contrast, the pulmonate, Siphonaria laciniosa, is a rigid homer and does not migrate; foraging occurs only after sunset and when it is submerged. The patterns of activ- ity in both species occurred irrespective of tidal or lunar cycles. Rao and Ganapati (1971) reported that Cel- lana radiata from the tropical west coast of India exhibited homing behavior but with no in- dication of whether homing was temporary or permanent. They further reported that homing occurred only on rough substrata and not on smooth surfaces and that movement occurred only during submergence. Cellana radiata from the Jordan Gulf of Aqaba has been found to home temporarily on smooth, as well as rough surfaces. Cellana radiata from the Jordan Gulf of Aqaba exhibits the same temporary homing be- havior as reported by Branch (1975) for Patella (jranularis Limit' and by Macka\ and Under- wood (1977) for C. tramoserica (Sowerby). In addition, C. radiata generally fits the category of migratory species established by Branch (1981) for Patella spp. The homing behavior found in Siphonaria laciniosa is consistent with that of other siphonariids (Branch, 1981 and in- cluded references). The conditions and timing of foraging excursions in S. laciniosa are, however, different from that of other species summarized by Branch (1981) in occurring only when submerged and after sunset. Homing behavior among intertidal limpets is often considered as a response to minimizing desiccation. In the case of the homing behavior Vol. 99(2-3) April 29, 1985 THE NAUTILUS 79 of Cellana radiata reported here, homing is considered insignificant in relation to desicca- tion. C. radiata is a temporary homer with a temporary scar and the edge of the shell usually does not fit closely to the substratum. In addi- tion, during emersion the shell is raised from the substratum rather than being clamped down, the mantle cavity contains copius fluid and there is no formation of a mucus sheet reported by Wolcott (1973). In the case of Siphonaria laciniosa, however, homing is considered significant in reducing desiccation. S. laciniosa, a rigid homer, returns to a permanent scar following foraging and there is a good fit of the edge of the shell to the substratum on soft (calcareous) and hard bot- toms. And during emersion, the shell is clamped to the substratum. The significance of homing in Cellana radiata may be related to what Mackay and Underwood (1977, p. 215) proposed for Cellana tramoserica which, as noted above, are similar in homing behavior. They hypothesized "homing behavior as an adaptation which regulates local density and dispersion to maximize utilization of food resources and, thus, to reduce intraspecific com- petition for food at high densities of limpets". Support for this hypothesis in C. radiata may be found in the results of the movement through a 1 m2 area over a period of 58 days. During that period there was gradual emigration of marked individuals from the area and gradual immigra- tion of new individuals into the area. The result of the emigration and immigration was that the density of individuals within the unit area re- mained relatively constant. The pattern of shoreward or upward migra- tion in Cellana radiata during late September through November is considered as a response to the increase in sea level, increased food sup- ply and reduced physical extremes. As noted above, late September through November is the period of transition from lowest sea level (July through mid-September) to highest sea level (December through May). With an increase in sea level, more area is submerged for a longer period of time thus favoring increased food sup- ply in the form of microalgae and a reduction in physical extremes. Thus, C. radiata, microalgal grazer and feeding only when submerged, takes advantage of the increased area of suitable con- ditions. The observed seaward or downward movement of C. radiata that occurred begin- ning in late May more or less coincided with a gradual lowering of the sea level. It is con- sidered as an attempt to avoid the greater ex- tremes in the physical environment and reduced food supply. A similar pattern of migration described above with, however, varying degrees, has been found among some proso- branch gastropods occurring in the rocky inter- tidal on the Jordanian coast (Hulings, unpub- lished data). Siphonaria laciniosa responds in different ways to the change in sea level. As a non- migrant, it remains in the same position regard- less of the change in sea level. During the period of high sea level, it is submerged more often and for a longer period of time. It is during this period that S. laciniosa deposits egg ribbons during the night on exposed surfaces and that the hatching of veligers occurs (Hulings, in preparation). During the period of lowered sea level, air temperatures are higher and periods of emergence are longer. Thus, homing behavior as a response to lowered sea level minimizes desiccation. Although an investigation of predation was not conducted, observations indicate a high mor- tality rate in Cellana radiata compared to Siphonaria laciniosa based on the finding of empty shells on the beach. A mortality rate of 22% was found among marked S. laciniosa over a 10-month period (no comparable data for C. radiata). What portion of the mortality is attri- butable to predation is not known. Most of the empty shells of both limpets did not exhibit physical damage. The spatial distribution of Siphonaria laciniosa tends to be more clumped than widely dispersed. Pairs and groups of individuals occur- ring in close proximity to each other are fairly common. Recruitment into areas of established populations was noted, and in some cases, the recruits were close to older individuals. Thus, there appears to be no aggressive behavior nor territorial defense by S. laciniosa. A similar situation probably prevails in Cellana. radiata based on homers not dislodging new occupants. Limited data and observations show that where Cellana radiata is abundant, Siphonaria laciniosa is very low in abundance or absent and 80 THE NAUTILUS April 29, 1985 Vol. 99(2-3) vice versa. This pattern of density distribution often exists at the same vertical level within the midlittoral zone. Whether this indicates inter- specific competition between the two limpets re- mains to be elucidated. In addition, the area occupied by Cellana radiata is usually devoid of microalgal grazers other than Siphonaria laciniosa and vice versa. It would appear, there- fore, that competition for food is minimal. Acknowledgments The author wishes to thank Dr. Joseph Rose- water, U.S. National Museum of Natural History, for verification of the identification of the species. Thanks are also expressed to Dr. Jean de Vaugelas, University of Nice, for critical reading of the manuscript. Financial support by the Office of the Dean Resource, Yarmouk University is greatly acknowledged. LITERATURE CITED Anati, D. A. 1976. Balances and transports in the Red Sea and the Gulf of Elat (Aqaba). Israel J. Earth Sci. 25: 104-110. Branch, G. M. 1975. Mechanisms reducing intraspecific com- petition in Patella spp.: migration, differentiation and territorial behavior. J. Anim. Ecol. 44:575-600. 1981. The biology of limpets: physical factors. energy flow, and ecological interactions. Oceanogr. Mar. Biol. Ann. Rev. 19:235-380. Fishelson, L. 1973. Ecological and biological phenomena influencing coral-species composition on the reef tables at Eilat (Gulf of Aqaba, Red Sea). Mar. Biol. 19:183-196. Garrity, S. D. and S. C. Leving. 1983. Homing to scars as a defense against predators in the pulmonate limpet Sipho- naria gigas (Gastropoda). Mar. Biol. 72:319-324. Hulings, N. C. 1979. Currents in the Jordan Gulf of Aqaba. Dirasat 6:21-33. Mackay, D. A. and A. J. Underwood. 1977. Experimental studies on homing in the intertidal patellid limpet Cellana tramoserica (Sowerby). Oecologia 30:215-237. Morcos, S. A. 1970. Physical and chemical oceanography of the Red Sea. Oceanogr. Mar. Biol. Ann. Rev. 8:73-202. Paldor, N. and D. A. Anati. 1979. Seasonal variations of temperature and salinity in the Gulf of Elat (Aqaba). Deep-Sea Res. 26:661-672. Rao, M. B. and P. N. Ganapati. 1971. Ecological studies on a tropical limpet, Cellana radiata. Mar. Biol. 9:109-114. Safriel, U. and Y. Lipkin. 1964. On the intertidal zonation of the rocky shores at Eilat (Red Sea, Israel). Israel J. Zool. 13:187-190. Stephenson, T. A. and A. Stephenson. 1949. The universal features of zonation between tidemarks on rocky coasts. J. Eeol. 37:289-305. Underwood, A. J. 1979. The ecology of intertidal gastro- pods. A dv. Mar. Biol. 16:111-210. Wolcott, T. G. 1973. Physiological ecology and intertidal zonation in limpets (Acmaea): a critical look at "limiting factors". Biol. Bull. 145:389-422. MEETINGS Western Society of Malacologists August 18-21, 1985 The annual meeting of the Western Society of Malacologists will be held on the campus of the University of California, Santa Barbara. The main emphasis will be on the molluscan fauna of the Eastern Pacific with sessions including land snails, paleontology, etc. There will also be a symposium on Hawaiian mollusks chaired by Mrs. Beatrice Burch. Anyone interested in pre-registration or call for papers please contact William D. Pitt, presi- dent, WSM, 2444 38th Ave., Sacramento, CA 95822. Telephone (916) 428-3899, home even- ings. DEATHS Joseph Rosewater, 1928 - 1985 Joseph Rosewater, Curator of Mollusks at the U.S. National Museum since 1960, a past-Presi- dent of the American Malacological Union, and a long-time contributor to The Nautilus, died after a relatively short illness on March 22, 1985, in Washington, DC, at the age of 56. He is survived by a son, two daughters and his widow, Mary Carlson Rosewater, 818 Woodley Drive, Rockville, MD 20850. An obituary and list of his publications will appear in the joint Clench- Rosewater memorial issues of the 100th Anni- versary volume of The Nautilus in 1986. We are informed that a fellowship fund for visiting mollusk students will be set up at the Smith- sonian Institution in memory of Dr. Rosewater. Vol. 99 (2-3) April 29, 1985 THE NAUTILUS 81 THE LAND SNAIL FAMILY HYDROCENIDAE IN VANUATU (NEW HEBRIDES ISLANDS), AND COMMENTS ON OTHER PACIFIC ISLAND SPECIES Fred G. Thompson Florida State Museum University of Florida Gainesville, FL 32611 and Emilye L. Huck P.O. Box 4413 Winter Park, FL 32793 ABSTRACT Georissa obsoleta new species (Gastropoda, Prosobranchia, Archeogastropoda, Hydrocenidae) is described from- Efate Island, Republic of Vanuatu. It is charac- terized by its minute size, obsolete sculpture, channelled suture, and conical form. It is the first record of Hydrocenidae from Vanuatu. Relationships with other Pacific species are not clear. The Hawaiian Georissa neili Pilsbry, 1928 is synonymizedwithG. cookei Pilsbry, 1928. G. kauaiensis Pilsbry, 1928 (Hawaiian Islands). Chondrella striata Pease, 1871 (Cook Islands), and Cyclostoma minutissima Sowerby, 1832 (Pitcaim Island) are based on juvenile specimens but appear to be Georissa. Key words: land snails, Hydrocenidae, Georissa obsoleta, Pacific Islands, Vanuatu, New Hebrides Islands, Efate Island. During June- August, 1984 the junior author had the opportunity to visit the Republic of Vanuatu, formerly called the New Hebrides Islands. Significant collections of land snails were made on Efate, Erromango, and Tanna. The collections are particularly interesting because of the large number of minute species that were recovered from leaf-litter samples gathered at many stations. A species of par- ticular interest to us is described below. It is the first record of the family Hydrocenidae from Vanuatu. Hydrocenid land snails are widely deployed on Pacific islands, Japan, New Zealand, Australia, the Indo-Australian archipellago, Southeast Asia, Madagascar, Africa, and Mediterranean Europe. They are poorly known because of their minute size and cryptic behavior, although they may be locally abundant (Thompson and Dance, 1983). Most species are confined to limestone substrates and encrust their shells with lime or mud. Live specimens appear more like minute blobs of dirt than like coiled shells. Thus, it is not surprising that this family was not reported in the two principal papers on the New Hebrides fauna (Solem, 1959, 1962). Because the new species has very poorly developed shell sculpture we name it: Georissa obsoleta Thompson and Huck, new species Shell (Figs. 1-7): Minute, adults about 1.7-1.9 mm long, about 0.72-0.78 times as wide as high. Color varying from yellow-gray to fulvous in fresh shells. Conical with a wide rounded apex; consisting of 3.3-3.7 whorls. Apex rounded, with a large cap-shaped protoconch consisting of 1.3 whorls (Fig. 6). Protoconch sculptured with a dense mesh of minute pits. Suture between whorls of teleoconch very deeply impressed, forming a channel around middle of shell (Fig. 5). Sculpture of teleoconch consisting of very weakly developed spiral threads that form an obsolete cancellate pattern where they cross growth striations and threads (Fig. 2). Growth threads tend to be enlarged above shoulder of whorl and usually form weak denticles along second and third whorls (Fig. 5). Aperture ovate in shape, about as wide as or slightly wider than high; about 0.39-0.48 times length of shell. Parietal wall nearly straight, lying at an angle of 30-32° to axis of shell (30° in holotype); plane of aperture at 20-25° to shell axis (Fig. 3). Um- bilical area with a wide shield that is indented along outer edge (Fig. 7). Parietal septum ex- tending into shell for % whorl, where upon the earlier septum has been readsorbed (Fig. 4). 82 THE NAUTILUS April 29, 1985 Vol. 99(2-3) ' © L-9 Georissa obsoleta Thompson and Huck, new species. 1. UF 50628a (x31). 2, UF 50629a(x31). 3. UF 50629a i F 50627 (x31). 5, UF 50628b (xl64). 6, UF 50628b ( x 205). 7, UF 50628a(x62). 8. inner surface of operculum i 9, oblique view of operculum at 70° from base (x82). Vol. 99(2-3) April 29, 1985 THE NAUTILUS 83 Measurements for the holotype and five para- types (UF 50633) selected to show variation follow: length width apert. h apert. whorls 1.64 1.89 1.80 1.71 1.61 1.24 1.40 1.40 1.27 1.24 0.74 0.76 0.84 0.74 0.74 0.74 0.87 0.84 0.74 0.74 3.6 3.7 3.6 3.5 3.1 holotype paratype paratype paratype paratype Operculum (Figs. 8, 9): Calcareous, concentric with a large subcentral nucleus. Inner surface with a long slender peg along columellar margin. Peg lying at a relatively low angle to plane of operculum; dorso-ventrally flattened; base of peg extending out to columellar edge of operculum. Innter surface of operculum flat, with a narrow raised callus around edge (Fig. 8), but not to the extent that occurs in Chondrella parva (Pease, 1864). Type locality: Vanuatu, Efate Island, above Mele village along trail to the cascades, 75 m altitude. Holotype: UF 50631; collected 23 June 1984 by Emilye L. Huck. Paratypes: UF 50632 (57), UF 50633 (13 measured specimens), UF 50634 (11), UF 50627 (1 gold plated), UF 50628 (2 gold plated), UF 20629 (2 gold plated), Bernice P. Bishop Museum 207565 (6), Austra- lian Museum C144145 (5), Rijksmuseum van Natuurlijke Historie 55724 (5); same locality as holotype. The type series was collected from leaf-litter samples gathered at the base of a limestone knoll at the edge of a banana grove in a dense rain forest, along the cascades of a small river near Mele village. Most of the specimens are slightly weathered. A few specimens are in fresh condition and retain the natural color. The holotype is a slightly immature specimen selected because it is the freshest specimen in the lot, it shows details of sculpture and color and the operculum is retained within the aper- ture. The paratypes illustrated in Figs. 1, 2 (UF 50628a) are nearly identical to the holotype but are very slightly larger. The figured operculum was recovered from a paratype (UF 50632). features distinguish the species from all other known Pacific Georissa. Five other species are described as being smaller, but their original descriptions appear to be based on juveniles and better material has not been reported. It is difficult to determine specific relation- ships because very little is known about the Pacific Hydrocenidae. Six species have been described from the northern and eastern Pacific. Three are recorded from Kauai, Hawaiian Islands, Georissa cookei Pilsbry, 1928, G. neili Pilsbry, 1928, and G. kauaiensis Pilsbry, 1928. The three were recovered from moss samples collected from fallen logs on a ridge be- tween Hanalei and Wailua. The type specimens of all three are juveniles, and each is known from only one or two specimens. On the basis of variation that we have seen in other species (see Thompson and Dance, 1983) we suspect that G. cookei and G. neili are the same species, and we have little faith in the distinction of G. kauaien- sis. Regardless of their specific status, their juvenile shells do not permit comparisons with other species because definitive characteristics of size, shape, sculpture and whorl development cannot be determined. One species is known from the Cook Islands, Chondrella striata Pease, 1871, and one is described from Pitcairn Island, Cyclostoma minutissima Sowerby, 1832. Both appear to be typical Georissa and both are based on juvenile shells. Thus it is not possible to discuss their characteristics for the purpose of specific com- parisons, other than to say that they are sculp- tured more heavily than is G. obsoleta. Another species is recorded from the Society Islands, Cyclostoma parva Pease, 1864. It is much larger and smoother than G. obsoleta, and is placed in a separate genus, Chondrella, because of a heavy callused ridge around the in- side margin of the operculum. Other species are known from New Zealand, Australia, and islands to the north, but close relationships between G. obsoleta and these are not apparent. Discussion Georissa obsoleta is characterized by its minute size, its moderately wide, conical form, its channelled suture, and its sculpture. These Acknowledgments The junior author traveled to the Republic of Vanuatu (New Hebrides Islands) assisted by a grant provided by The Explorers Club Educa- 84 THE NAUTILUS April 29, 1985 Vol. 99(2-3) tion and Youth Activities Fund and the Haver- lee Exploration Fund of the Central Florida Chapter of The Explorers Club. We wish to ex- press our gratitude to the society for this aid, and to Dr. R. Tucker Abbott for his encourage- ment. She was accompanied in the field by her mother, Robin B. Huck. Harvey A. Miller (University of Central Florida) led the expedi- tion while pursuing studies on Pacific bryo- phytes under the sponsorship of the National Science Foundation (Grant BSR-8215056). The SEM micrographs comprising the illustrations in this paper were prepared by Kurt Auffenberg (Florida State Museum) from the HITACHI S415A Scanning Electron Microscope in the Department of Zoology, University of Florida. George M. Davis (Academy of Natural Sciences, Philadelphia) loaned us specimens of Cyclostoma parva Pease for comparison. A discussion of its specific and generic status will be presented elsewhere by the senior author. We wish to ex- press our gratitude to all people who have assisted us in this study. LITERATURE CITED Pease, W. H. 1864. Descriptions of new species of land shells from the islands of the Central Pacific. Proe. Zool. Soc. Lond. for 1864: 668-678. 1871. Catalogue of the land shells inhabiting Polynesia, with remarks on their synonymy, distribution and variation, and descriptions of new genera and species. Proc. Zool. Soc. Lond, for 1871: 449-477. Pilsbry, H. A. 1928. Georissa, a land snail genus new to the Hawaiian Islands. Bull. Bernice P. Bishop Mus. 47:3-4. Solem, A. 1959. Systematica of the land and freshwater Mollusca of the New Hebrides. Fieldiana (Zool.) 43: 1-238; pis. 1-34. 1959. Notes on. and descriptions of New Hebridean land snails. Bull. British Mus. (Nut Hist.) 9:213-247; pis. 1-2. Thompson, F. G. and S. P. Dance. 1983. Non-marine mol- lusks of Borneo. II Pulmonata: Pupilliade, Clausiliidae. Ill Prosobranchia: Hydrocenidae, Helicinidae. Bull. Fla. Stat. Mus. (Biol. Sci.) 29(3): 101-130; Figs. 1-75. COMMENTS ON THE DISTRIBUTION OF FRESHWATER MUSSELS (UNIONACEA) OF THE POTOMAC RIVER HEADWATERS IN WEST VIRGINIA Ralph W. Taylor Department of Biological Sciences Marshall University Huntington, WV 25701 ABSTRACT This report presents data collected in 1981 and 1984 on the mussels of the upper Potomac River located within the eastern panhandle of West Virginia. My data indicate that North Branch is devoid of mussels apparently as a result of extensive strip mining; South Branch has a small but healthy mussel population. The Cacapon River and Patterson Creek, tributaries to the Potomac, also have viable populations. Eight species of mussels were found in the Potomac headwaters. Elliptio complanata, E. fisheriana and Lampsilis ventricosa were fairly common and Alasmidonta varicosa, A. undulata, Anodonta cataracta, Strophitus undu- latus, and Lasmigona subviridis were uncommon throughout the system. Cor- bicula fluminea was found throughout the drainage with the exception of North r.nnich. The freshwater mussel fauna of the Potomac River headwaters is virtually unknown. Ort- mann (1919) has done the only previous exten- sive collecting in the region, and that was com- pleted around the turn of the twentieth century. He probably took a train to Romney, West Virginia, and then to Harpers Ferry to collect in the Potomac River over a distance that could be Vol. 99(2-3) April 29, 1985 THE NAUTILUS 85 covered in a day's ride by buggy. All of his records are in the immediate area of these two towns. Johnson (1970) reported that Carol Stein did limited collecting at Harpers Ferry in the early sixties. I can find no evidence of other work having been done in the upper Potomac River. The reasons for the paucity of work there in- clude: very poor roads (until recently) into the area; a very difficult terrain to maneuver; and limited access to the river at any point. Clarke (1981), Johnson (1970), and Ortmann (1919) all indicated a depauperate assemblage of mussels in this stream. My report does not dispel those findings. There are small popula- tions present but they are widely spread and oc- cur more often in the smaller tributaries than in the main trunk of the river. The only population of considerable size that I found was located at an area locally known as Pack Horse Ford, just downstream of Sheperdstown, West Virginia. All other areas reported herein represent small populations of no more than a couple of dozen specimens from any one site. The Potomac River originates in the Potomac highlands in the eastern panhandle of West Virginia. The mainstem Potomac River then continues along the Maryland/West Virginia border for Ca. 160 km to Harpers Ferry where it receives the Shenandoah River which has its headwaters in Virginia. I have not collected below Harpers Ferry. Two other major tribu- taries in West Virginia are the Cacapon River and Patterson Creek (Fig. 1). Ortmann (1919) collected in the South Branch Potomac River at Romney and Southbranch and reported the following species: Elliptio com- planata (Lightfoot, 1786), Lasmigona subviridis (Conrad, 1835), Anodonta cataracta Say, 1817, Strophitus undulatus (Say, 1817) and Alasmi- donta varicosa (Lamarck, 1819). He also reported E. complanata and A. varicosa from the Shenandoah River at Harpers Ferry. Clarke (1981) reported Alasmidonta undulata (Say, 1817) from the South Branch and Shenandoah rivers and A. varicosa from Cherry Run and Lost River, a small tributary of the Cacapon River. Johnson (1970) reported two additional: Lampsilis ventricosa (Barnes, 1823) and Ellip- tio fisheriana (Lea, 1838) [ = lanceolata (Lea, 1820)]. The Cacapon River and Back Creek are FIG. 1. Headwaters of the upper Potomac River. listed as the localities where these two mussels were collected. My collecting was done during the summers of 1981 and 1984. Collecting involved wading the streams and collecting specimens that had been observed through the use of a glass-bottomed viewbox (waterscope). The entire drainage was covered to the extent that it was practical. Many areas are virtually inaccessible and could be reached only by raft or canoe. The sites reported herein are the only ones where mussels were found in any appreciable numbers. At all other localities visited only an occasional isolated in- dividual was seen and seemed not to represent a viable population. Voucher specimens have been placed with the Ohio State University Museum and the Marshall University Malacological Col- lections. Collecting Sites 1. Potomac River at Pack Horse Ford, approx- imately 1 km E of Sheperdstown, Jefferson Co., WV, off County Road (CR) 17/1. 2. South Branch at U. S. Route (US) 50 Bridge, 1 km W of Romney, Hampshire Co., WV. 3. South Branch at Arnold Farm, S of Romney on CR 8/2, 9 km N of Hardy Co. line Hampshire Co., WV. 86 THE NAUTILUS April 29, 1985 Vol. 99(2-3) 4. South Branch, off CR 6, N of Village of Cunningham, Hardy Co., WV. 5. South Branch, bridge on US 220 at Peters- burg, Grant Co., WV. 6. Cacapon River, off SR 9, 5 km N of Village of Largent, Morgan Co., WV. 7. Cacapon River, along CR 15 at public fish- ing area, Hampshire Co., WV. 8. Cacapon River, 1.5 km S of Village of Capon Bridge on CR 14, Hampshire Co., WV. 9. Cacapon River at bridge on CR 9/12, Morgan Co., WV. 10. North River of Cacapon River, along Delray Road ( = CR 11), Hampshire Co., WV. 11. Patterson Creek, along CR 46 near Fort Ashby, Mineral Co., WV. 12. Patterson Creek, at intersection of CR 28/3 and CR 28/10, Mineral Co., WV. 13. Shenandoah River, at Harpers Ferry, Jefferson Co., WV. Discussion There are areas in the headwaters of the Potomac River drainage where small popula- tions of naiads still persist. The North Branch of the Potomac River, however, has no detectable mussel population. All the collecting sites showed signs of mining damage. The substra- tum was covered with heavy deposits of ochre indicating the presence of mining effluent. Cor- bicula Jluminea (Miiller, 1774) which was found everywhere else in the drainage, was not found in this major tributary of the Potomac. The rest of the headwaters showed little evidence of disturbance by man. Presently, most of the area is fairly pristine with no industry or logging ac- tivities. Farming centers around the production of apples so there is little stream siltation. Species Accounts Elliptio complanata: This species was the most commonly found species in the study area and was found at nearly every collection site. Elliptio fisheriana: Johnson (1970) stated that this may simply represent a northern form of Elliptio lanceolata. E. fisheriana is, however, being recognized by the committee of the American Malacological Union which is current- ly preparing a list of generally accepted names for the naiads. While never found in abundance, it is widespread throughout the headwaters. Lampsilis ventricosa: This species is normally an interior basin species. It was inadvertently introduced into the Atlantic drainage about the turn of the century. It has become well estab- lished and is quite common throughout much of the drainage. It has apparently replaced the resident species Lampsilis cariosa (Say, 1817) in the upper Potomac River. The Ohio State University Museum of Zoology has several specimens of L. cariosa from the lower Potomac TABLE 1. Distribution of naiad mussels in the headwaters of the Potomac River system by species. Site Number z1 2 3 4 5 6 7 8 9 10 11 12 13 Elliptio complanata X X X X XXX X X X Elliptio fisheriana X X X X Lampsilis ventricosa X X X X X X X X Alasmidonta varicosa X X X X X Alasmidonta undulata X X Anodonta cataract a X X Lasmigona subviridis X X X Strophitus undulatus X X Vol. 99(2-3) April 29, 1985 THE NAUTILUS 87 but none from this reach (Stansbery, 1984, pers. comm.). Ahisiiiiilniiii! varicosa: Apparently fairly com- mon throughout the headwaters. Widespread throughout the Atlantic coastal drainages. Alasmidonta undulata: This species is ap- parently quite rare here as only five specimens were found. Widespread throughout the Atlan- tic coastal drainages. Anodonta cataracta: This species does not ex- hibit a widespread distribution in the head- waters. It is typically found in larger, slower- flowing bodies of water. Only four specimens were found during this study. Lasmigona subviridis: This small species may be more abundant than my collections indicate. It is a typical Atlantic coastal species and enjoys a widespread distribution in most of eastern North America. It has crossed the mountain barrier on at least one occasion and can be found in the New River system (a tributary of the Ohio River) of southern West Virginia. One specimen was found at each of three different collecting stations during this study. Strophitus undulatus: This species is not com- mon. Ortmann (1919) reported it only from South Branch at Romney. I found a single live specimen in Patterson Creek and a badly- weathered half shell in the Shenandoah River. LITERATURE CITED Clarke, A. H. 1981. The Tribe Alasmidontini (Unionidae: Anodontinae), Part I: Pegias, Alasmidonta, and Arcidens. Smithsonian Contributions to Zoology. No. 326, 101 p. Johnson, R. I. 1970. The Systematies and Zoogeography of the Unionidae (Mollusca: Bivalvia) of the Southern Atlan- tic slope Region. Bulletin of the Museum of Comparative Zoology. No. 140(6):263-449. Ortmann. A. E. 1919. A monograph of the Naiads of Penn- sylvania. Part 3. Systematic account of the genera and species. Memoirs of the Carnegie Museum 8:1-384. A SECOND MELAMPID (PULMONATA: BASOMMATOPHORA) FROM THE EARLY MIOCENE OF VENEZUELA J. Gibson-Smith and W. Gibson-Smith Quinta Puerta del Sol, Calle Tucupido, San Roman, Las Mercedes, Caracas 1060, Venezuela ABSTRACT Pedipes cf. P. mirabilis (Muhlfeld, 1816) was reported by the present authors (1979, p. 22) from the early Miocene (Burdigalian) Cantaure Formation, Paraguand Peninsula, Venezuela, being the first reported fossil occurrence of the genus. It is described now as the new species Pedipes mirandus and is considered to be the ancestor of the Recent cognate species P. angulatus C. B. Adams, 1852, from the Eastern Pacific and P. mirabilis from the Western Atlantic. The presence in the early Miocene (Burdi- galian) Cantaure Formation, Paraguana Penin- sula, Venezuela, of two members of the family Melampidae was reported by Gibson-Smith & Gibson-Smith (1979, p. 22). One of these, Tralia cf. T. ovula (Bruguiere, 1789), was later de- scribed by these authors (1982, p. 119) as the new species T. venezuelana, which lives along the north coast of Venezuela, occurring also in the late Pliocene Mare Formation, Cabo Blanco, Venezuela. This was only the second fossil record of the genus Tralia the other being T. vetula Woodring, 1928, from the Pliocene Bowden Formation, Jamaica. The second Can- taure form, Pedipes cf. P. mirabilis (Muhlfeld, 1816), the first fossil record of the genus, is likewise now recognized as a new species, Pedipes mirayidus. It is considered to be the ancestor of the Recent cognate species P. angulatus C. B. Adams, 1852, from the Eastern Pacific and P. mirabilis from the Western Atlantic. The genus was reviewed by Clench 88 THE NAUTILUS April 29, 1985 Vol. 99(2-3) (1964, p. 119) and the only other Recent taxa of the region are P. liratus Binney, 1860, and P. unisulcatus Carpenter, 1866, both from the Eastern Pacific. The author of Pedipes was said by both Clench (loc. cit.) and Keen (1971, p. 848) to be Ferussac, 1821, the former giving the type species as, "Pedipes afra Gmelin ( = P. pedipes Bruguiere), subsequent designation, Gray 1847." Abbott (1974, p. 333), on the other hand, gave the author as Bruguiere, 1792, with type species [Helix] afer Gmelin. According to Clench (loc. cit.) afer is a Pfeiffer, 1856, misspelling of afra. Zilch (1959, p. 68) was the first to name Bruguiere, 1792, as the author, the type species being Bulimus pedipes Bruguiere, 1789, by tautonymy. Subfamily Pedipedinae Crosse & Fischer, 1880 Genus Pedipes Bruguiere, 1792 Type species, by tautonymy, Bulimus pedipes Bruguiere, 1789. Pedipes mirandus Gibson-Smith & Gibson-Smith, n. sp. Figure 1 Description: Shell minute. Protoconch hetero- strophic, submerged, last V2-whorl inclined, smooth. Teleoconch of 3Vi shouldered whorls, body whorl globose. Sculpture of flat, subequal spiral cords with narrower interspaces, sub- sutural cord prominent; 4 cords between it and the shoulder and about 23 below. Surface rough- ened by crowded, prosocline growth incremen- tals. Columella broad, inclined, with two in- clined folds, the lower the weaker. Parietal callus narrow, carrying a large fold lying closer to the anal notch than to the upper columellar fold. Outer lip thin, smooth within. Holotype: Natural History Museum Basel, No. H 17113. Height 2.25 mm, diameter 1.75 mm. Type locality: Known only from the lower shell- bed of the early Miocene Cantaure Formation, Paraguana Peninsula, Venezuela (GS-1-PGNA). Paratype: Paleontological Research Institution, PRI 30049. Remarks: The type material consists of 5 small, complete specimens and, in the absence of even fragments of larger shells, are believed to be mature. While the absence of a labral den- ticle might suggest immaturity it is not a FIG. 1. Pedipes mirandus n. sp. Holotype, ventral view. Height 2.25 mm, diameter 1.75 mm. Early Miocene Can- taure Formation. Paraguana Peninsula, Venezuela. NHMB H 17113. SEM micrograph, x25. characteristic of all mature Pedipes, the equally small P. liratus also lacking a denticle (Keen, 1971, fig. 2411). Comparison has been made with juvenile P. mirabilis of a similar size. The trivial name is from the same Latin root as mirabilis meaning "wonderful" or "singular". Comparisons: P. mirandus n. sp. is most closely related to P. angulatus and P. mirabilis, the sculpture and outline being similar. In its broad columella it more resembles P. angulatus and in the reduced extent of the parietal callus it more resembles P. mirabilis. It differs from both in being smaller with 1 or 2 fewer whorls, in having an inclined columella and inclined col- umellar folds, the lower smaller than the upper; in P. angulatus and P. mirabilis the columella is vertical, the folds are about equal in size and are horizontal. In both of these, moreover, the parietal folds lies midway between the upper columellar fold and the anal notch, whereas in P. mirandus the fold lies closer to the anal notch, dividing the gap into one-third and two-thirds, and it is more horizontally directed. LITERATURE CITED Abbott, R. T. 1974. American Seashells, 2nd edit., 663 pp., 24 col. pis., text figs. Van Nostrand Reinhold Co., New York. Clench, W. .1. 1964. The genera Pedipex and Lacntadontti Vol. 99(2-3) April 29, 1985 THE NAUTILUS 89 in the Western Atlantic. Johnsonia 4(42):117-127, pis. 76-79. Gibson-Smith, J. and W. Gibson-Smith. 1979. The genus Arcinella (Mollusca: Bivalvia) in Venezuela and some associated faunas. Geos No. 24, pp. 11-32, 3 pis. 1982. The subfamily Melampinae (Pulmonata: Basommatophora) in Venezuela, with descriptions of two new species. TheNautilus 96(3):1 16-120, 9 figs. Keen, A. M. 1971. Sea shells of tropical West America; marine mollusks from Baja California to Peru. 2nd. edit., Stanford Univ. Press, Calif., i-xiv + 1064 pp., ca. 4000 text figs., 22 col. pis. Zilch, A. 1959. Gastropoda: Euthyneura. In Wenz's Hand- buch der Palaozoologie. Lief. 1, pp. 1-200. LICENSED APPRAISALS AND IDENTIFICATION SERVICE Collections of shells and libraries of shell books expertly appraised for estate, gift and tax purposes. Moderate fees, plus travel ex- penses. Services confidential. Inquire below. 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Tucker Abbott American Malacologists, Inc. Box 2255, Melbourne, FL 32902-2255 Mrs. Cecelia W. Abbott Business and Subscription Manager P.O. Box 2255 Melbourne, FL 32902-2255 Second Class Postage paid at Melbourne, Florida and other post offices The Nautilus (USPS 374-980) ISSN 0028-1344 A quarterly magazine devoted to malacology. Copyright °1985 hy American Malacologists, Inc. OFFICE OF PUBLICATION American Malacologists, Inc. (United Parcel Address: 2208 South Colonial Drive, Melbourne, FL 32901) Mail: Box 2255, Melbourne, FL 32902-2255 POSTMASTER: Send address changes to above. Subscription Price: $15.00 (see inside back cover) $17.00 (foreign); institutions $20.00 CONTENTS THE NAUTILUS Volume 99, number 4 - October 31, 1985 ISSN 0028-1344 Twila Bratcher and Walter O. Cernohorsky Three New Deep-Water Indo-Paeifie and One Intertidal Brazilian Species of Terebra (Gastropoda) 91 Dorothea S. Franzen Succinea vaginacontorta Lee (Gastropoda: Pulmonata: Succineidae) 94 Harald A. Rehder A New Species of Coralliophila (Gastropoda: Coralliophilidae) from Southeastern Polynesia .... 97 Raymond W. Neck Native Freshwater Mussels (Unionacea) as Fouling Agents in Electrical Generating Plants. . . 100 William K. Emerson Teramackia dupreyae New Species, from off Western Australia (Gastropoda: Volutidae) 102 Scott J. Herrmann and James R. Fajt Additional Colorado Records of Anodonta grandis grandis Say (Bivalvia: Unionidae) 107 James E. Joy A 40-Week Study on Growth of the Asian Clam, Corbicula flnmirwa (Midler), in the Kanawha River, West Virgina 110 Paul D. Hartfield and Richard G. Rummel Freshwater Mussels (Unionidae) of the Big Black River, Mississippi 116 Courtney T. Hackney Variations of Shell Morphology in the Carolina Marsh Clam, Polymesoda caroliniana, from Southeastern United States (Corbiculidae) 120 Randal L. Walker Growth and Optimum Seeding Time for the Hard Clam, Mercenaria mercenaria (L.), in Coastal Georgia 127 Dorothea S. Franzen Anatomy of Oxyloma nuttalliana chasmodes Pilsbry 134 Riidiger Bieler, Arthur S. Merrill and Kenneth J. Boss Pseudotorinia bullisi. New Species (Gastropoda: Architectonicidae) from Subtropical Western Atlantic 139 Arthur E. Bogan A Comment on Strophitinae Gordon, 1981 (Unionidae, Bivalvia) 141 Mark E. Gordon and John L. Harris Distribution of Lampsilis powelli (Lea) (Bivalvia: Unionacea) 142 NOTICE TO SUBSCRIBERS Please examine your last number of The Nautilus (vol. 99, no. 2-3 of April 1985). A few copies were in- advertently reversed in the press, so that the paginations of perhaps three dozen copies were improperly printed. If page 47 is backed by page 52, or page 49 is backed by page 54, you will know that you received an imperfect copy. If so, please write The Nautilus, P.O. Box 2255, Melbourne, FL 32902, USA, and a good copy will be mailed to you free of any charge. Destroy, or cut-up for reprints, the imperfect copy. -R.T.A. *m&'*-;m$ !mki>-'*$lMii3& New from Field Museum of Natural History The Distributions of the Native Land Mollusks of the Eastern United States By Leslie Hubricht Leslie Hubricht's long-awaited summation of the land mollusks of the eastern United States is now available from: Field Museum of Natural History Division of Publications Roosevelt Road at Lake Shore Drive Chicago, 1L 60605-2496 The first comprehensive treatment of this fauna since Pilsbry's Land Mollusca oj North America (North of Mexico), published from 1939 to 1948, it is based on 50 years of collecting by the author, his review of major museum collections, and analysis of the immense literature published since 1948. Every species and subspecies recognized by Hubricht has a map showing all county records plus a summation of system- atically important literature records, notes on occurrence, and remarks on variation . This will be the authoritative work for the next 50 years! Fieldiana: Zoology New Series, No. 24 Pub. Date, June 28, 1985 Publication No. 1359 Soft cover, 191 pages, 523 maps Price: $23.00 (postpaid) Note: On orders from Illinois residents, appropriate sales tax should be included Completely Revised and Expanded Between Pacific Tides Fifth Edition Edward F. Ricketts Jack Calvin & Joel W. Hedgpeth Revised by David W. Phillips Including John Steinbeck's Foreword to the 1948 edition. One of the classic works of marine biology, Between Pacific Tides describes the habits and habitats of the animals that live in one of the most prolific life zones in the world — the rocky shores and tide pools of the vast Pacific Coast. Now completely revised, expanded by nearly 20%, and incorporating over 200 new illustrations and a new chapter on the factors that influence the distribution of organisms along the shore, it is an unsurpassed introductory text for students and professionals and an invaluable guide for the amateur. The Index and Bibliography now contain some 2,300 entries. Illustrated with 425 photographs and drawings. $29.50 STANFORD UNIVERSITY PRESS Vol. 99 (4) October 31, 1985 THE NAUTILUS 91 THREE NEW DEEP-WATER INDO-PACIFIC AND ONE INTERTIDAL BRAZILIAN SPECIES OF TEREBRA (GASTROPODA) Twila Bratcher 8121 Mulholland Terrace Hollywood, CA 90046 and In 1982 on cruise 32 of R. V "Marion-Dufresne", under the direction of Dr. A. Guille, terebrid specimens were dredged from fifteen stations off Reunion Island in the Indian Ocean. On board were malacologists Dr. Philippe Bouchet, A. H. Waren, and B. Metivier. Two species new to science were dredged along with several un- common species. Among them were Hastula celidonota (Melville & Sykes, 1898), the only member of the genus with a dark dorsal splotch; Terebra virgo Schepman, 1913, a species with a white shell somewhat resembling T. funiculata Hinds, 1844; a range extension of Terebra mac- tanensis Bratcher and Cernohorsky, 1982 (the white color form). Those from Reunion Island differ from the typical form by having regular yellowish brown dots between the ribs on the subsutural band while those of the typical form are scattered irregularly. All the specimens mentioned above are in the collection of the Museum National d'Histoire Naturelle of Paris. A large new terebrid species, 97.6 x 14.4 mm, was dredged off the coast of Natal, South Africa, in 1983. The eastern continental shelf off South Africa, where this species was found, has barely been studied. The shelf was last dredged in 1901, other than incidental hauls made by Dr. R. N. Kilburn of the Natal Museum and Dr. Allan Connell. (Dr. R. N. Kilburn, pers. comm.) This no doubt is the explanation of why so large a species has remained undiscovered until the present time. The third new species is from the Western Atlantic and has been collected intertidally to 30 m. It has been misidentified by dealers and others as T. doellojuradoi Carcelles, 1953. Family Terebridae Morch, 1852 Terebra Bruguiere, 1789 Terebra Bruguiere. Encycl. Meth. Hist. Nat. Vers l:xv. Type species by SD (Lamarck. 1799): Bucrnixm suhuhitiim Linnaeus, 1767. Recent; Indo-Pacific. Walter O. Cernohorsky Auckland Institute and Museum Auckland, New Zealand Terebra pseudopertusa Bratcher & Cernohorsky, sp. nov. (Figs. 4. 5) Diagnosis: A terebrid similar to Terebra pertusa (Born, 1778), but with the shell having mamillate protoconch and an extra row of squarish, brown maculations below the sub- sutural band and at the periphery of the body whorl. Description: Shell shiny, of moderate size for the genus with 13 whorls in the teleoconch; protoconch of IV2 mamillate whorls; outline of whorls straight; subsutural band defined by a groove and with punctations between the ribs; axial ribs sharp, 15 on penultimate whorl, with wide interspaces; interspaces with 5 spiral grooves not crossing ribs; body whorl with ribs fading out at periphery, smooth below; aperture quadrate; columella slightly recurved; color yellowish with dark-brown maculations between white-topped ribs on the subsutural band and at the periphery of the body whorl. Dimensions: Holotype 36.1 x 6.2 mm; para- types from 10.4 x 2.4 to 36.2 x 6.3 mm. Type Locality: Reunion Is., Indian Ocean (21°06'S, 55°01"E) at 80-83 m depth. Type Material: Holotype and 6 paratypes in MNHNP; 1 paratype in the Bratcher collection. Distribution: From South Africa to Papua New Guinea, in depths to 110 m. Discussion: This species was originally thought to be a color form of T. pertusa (Born, 1778), until a specimen was examined with its mamillate protoconch intact. All specimens with the extra row of maculations subsequently ex- amined also posessed paucispiral protoconchs. T. pertusa has a multispiral protoconch, always lacks the additional rows of maculations, and grows to a much larger size (97.5 mm) than any specimens of this species examined. 92 THE NAUTILUS October 31, 1985 Vol. 99 (4) L-6 1, Ten-bra riosi Bratcher & Cernohorsky, new species. Holotype LACM no. 1974. 9.8 x 2.5 mrn^ 2 and 6, 8, pi. 9, fig. 3; Franzen. 1971, Nautilus 84(4), 131-142, tables 2, figs. 3. Succinea Indiana Pilsbry, Hubricht, 1961, Nautilus 72(2), insert in reprint, p. 60. Succinea indiana Pilsbry, Hubricht. 1985. Fieldiana Pub No. 1359: 15, Map p. I 17. The employment of anatomical structures of soft parts, radulae, pigmentation patterns as well as shell characteristics is generally essen- Vol. 99(4) October 31, 1985 THE NAUTILUS 95 tial for accurate identification of species of Succineidae. Unfortunately, historically, many collectors and authors of species of succineas based their descriptions solely on shell char- acters. They did not describe, illustrate or preserve the soft parts, therefore, we have to rely on comparisons of shells with those of holo- types and/or paratypes. Some types were cata- logued in private collections which in some instances cannot be located. Pilsbry (1948, p. 818) illustrated the shell and reproductive structures of a succineid which he identified as a Succinea aurea Lea from Cape May, New Jersey. The type locality of the species is "Springfield, Ohio." To date I have been unsuccessful in locating the holotype and/ or paratypes of S. aurea Lea. Pilsbry (ibid) placed Succinea Indiana Pilsbry, 1905, into the synonomy of 5. aurea Lea. He described only the shell and did not illustrate or describe the soft anatomy of S. indiana. Hubricht collected a live succineid, which he identified asS. indiana Pilsbry, from a loess hill- side near New Harmony, Indiana, presumably the type locality of the species. "Upon dissection of the animal it was found to be unrelated to S. aurea Lea, in the synonomy of which it was later placed by Pilsbry (Pilsbry, 1948). The penis is similar to that of Succinea campestris Say, the mantle is dark gray without the spots character- istic of S. concordialis Gould. Succinea indiana must, therefore, be considered a distinct species belonging to section Calcisuccinea Pilsbry." (Hubricht, 1958, 60-61). Hubricht (1961, 60) reported from a later collection he made from presumably the type locality of S. Indiana, "A careful examination of the anatomy and shell of topotypes Succinea indiana showed no charac- ter which could be used to distinguish it from S. vaginacontorta. The same twisted vagina is found in S. indiana. S. vaginacontorta Lee must be placed in the synonomy of 5. indiana." Pilsbry (1948, p. 817) quotes his 1905 descrip- tion of Succinea indiana, "Shell obesely ovate, thin, brownish amber or raw sienna colored, the apex reddish. Sculpture of fine growth-lines and wrinkles, becoming rather coarse wrinkles on the last half whorl. Whorls 3V2, very convex, the last large and inflated. Aperture large, oblique, the outer lip either regularly arcuate or some- what flattened in the middle. Columella thin and strongly arcuate throughout." Because soft parts of the holotype and para- types of Succinea indiana Pilsbry have not been described or preserved and, therefore, are not available for examination, comparisons of that species with S. vaginacontorta Lee are here based on shell characteristics of the holotype and paratypes of S. indiana and topotypes of S. vaginacontorta, their habitats and geographic distribution. Shell Characteristics Succinea vaginacontorta Lee, section Cal- cisuccinea Pilsbry, 1948. Lee described the shell of the holotype, "Shell is dextral, fully devel- oped. Whorls, 3, with suture only moderately impressed. Whorls which increase proportion- ately from the apex to the body whorl with no marked discontinuity in size. In life shell is a dull, translucent, light, horn yellow with green- ish tones. Striae present and well raised (PI. 1, Fig. 3). Epidermis of upper whorl eroded away revealing dull white deeper layers of shell, parietal wall with well-developed callus, cover- ing base of slightly curved columella (PI. 1, Fig. 2). Aperture obliquely ovate with a slight flare at base of outer lip. Interior of aperture with a thin shiny transparent sheen." (Lee, 1951, 3). Significant shell differences of the two species can be noted in Fig. 1, and are here listed: 1. Succinea vaginacontorta is more elongate-ovate than S. indiana. S. vaginacontorta attains a height up to 12.3 mm (Franzen, 1971, Table I). Height of holotype of S. indiana, 11.0 mm. 2. Nuclear whorl of both species knob-like; that of S. vagina- contorta large and more prominent; of S. indiana reddish brown. 3. Spire of S. vaginacontorta more tightly twisted and acute-elongate than of S. indiana. First whorl of S. vaginacontorta larger than of S. indiana. 4. Whorls of S. indiana more inflated and shouldered; body whorl more inflated, roundly ovate and aperture more elongate-ovate than of S. vaginacontorta. 5. Peristome of S. vaginacontorta sharp, continuous as a well-developed callus on body wall and covering the col- umella as it ascends. Columella of S. indiana white, re- curving as it disappears into ultimate whorl; callus on body wall thin. 6. Periostracum of S. vaginacontorta thin, dull, light horn yellow, readily removable exposing the deeper, white layers of the shell. Striae heavier and coarser than of S. indiana which produce a rough appearance on surface of ultimate whorl. Due to the heavy striations the shell, when stripped of its periostracum, has a striped appear- ance. Periostracum of S. indiana yellow-amber, doesn't 96 THE NAUTILUS October 31, 1985 Vol. 99 (4) FIG. 1. A, B. Topotype of Succinea vaginacontorta Lee. Height, 10.7 mm. C, D. Holotype of Succinea indiana Pilsbry. Height, 11.0 mm. peel as readily as of S. vaginacontorta; striae fine resulting in a shiny, silky surface. Habitats and Geographic Distribution Type locality of Succinea vaginacontorta Lee, SW corner of S 18, T 33 S, R 28 W, Meade Coun- ty, Kansas, "... a sagebrush Hat on which hairy gramma grass {Bouteloua hirsuta Lag.) was growing along a small creek ... It is not subject to flood. The nearest permanent water is Crooked Creek about one-half mile to the east. The hairy gramma grass occurred in thick stands with a few small patches between the stands. The snails lived on spots of lichens, mosses, and occasional liverworts between these patches." (Lee, 1951, 1-2). ". . . Succinea i-ngitiacoutarta Lee is xerophilous. Its usual habitat is a treeless slope of a hillside supporting a ground cover of short grass, sagebrush, and lichens. This species appears on the surface in the summertime after rains have soaked the ground. During periods of drought it disappears and may not be seen again for months or even years." (Franzen, 1971, 132). Average annual precipitation of Meade County, Kansas, is 18.72". (Yearbook of Agri., 1941, 874). Succinea vaginacontorta is known from localities of the high plains including Meade County, Kansas; Brown County, Nebraska; Washabaugh County, South Dakota; San Miguel County, New Mexico (Franzen, 1971) and later from other counties of SW Kansas; Yuma Coun- ty, Colorado; Sherman County, Texas; and Platte County, Wyoming. Succinea indiana Pilsbry was collected by L. E. Daniels in 1904 from ". . . just south of New Harmony, Posey Co., Indiana, on the hillside facing west between the marl cliffs and the highway." (Pilsbry, 1948, 817). I have visited the site a number of times and have observed changes. The hillside supports a growth of timber consisting of hardwoods up to its western slope. The west end of the hillside has been altered since the time Daniels collected the succineas. The slope facing the highway has been excavated. For a number of years the western end of the hill was burned annually which controlled the growth of the brush. In re- cent (about six or seven) years the area has not been burned; the brush has become dense and impenetrable. The average annual precipitation of Posey County, Indiana, is 42.34". (Yearbook of Agri. 1941, 855). The habitat of this site does not resemble that of the high plains where S. vaginacontorta is known to live. The geographic distribution, habitat, and shell characters distinguish Succinea vaginacontorta Lee from Succinea indiana Pilsbry. S. vagina- contorta is, therefore, not a synonym of S. indiana but a valid species. Acknowledgments National Science Foundation Grants-in-Aid No's. NSF G18000 and NSF GB2715 provided laboratory equipment and supported, in part, field studies. I am grateful to Dr. A. Byron Leonard for reviewing the manuscript. The Academy of Natural Sciences of Philadelphia graciously loaned me type specimens of Suc- cinea indiana Pilsbrj . Vol. 99(4) October 31, 1985 THE NAUTILUS 97 LITERATURE CITED Franzen, Dorothea S. 1971. Anatomy and Geographic Distri- bution of the Succineid Gastropod, Sucrinen cagitia- contorta Lee. The Nautilus 84(4):131-142. Tables I, II, Figs. 1-3. Hubricht, Leslie. 1958. Quickella vermeta and Sucdnea indiana. The Nautilus 72(2):60-61. 1961. Eight New Species of Land Snails From the Southern United States. The Nautilus 75(l,2):26-32, 60-63, PI. 4, figs. 1, 2. 1985. The Distribution of the Native Land Mol- lusks of the Eastern United States. Fieldiana, Zoology, New Series, No. 24, Publication 1359, Field Museum, 1-191; Maps 523. Lee, C. Bruce. 1951. Sucdnea vaginacontorta (Section Calci- succinea), A New Amber Snail from Kansas. Occ. Pap. Mus. Zooi. Univ. Mich.. No. 533 (Mar. 20): 1-7, Pis. I, II, Text fig. 1. Leonard, A. Byron. 1959. Handbook of Gastropods in Kansas. Univ. Kans. Mus. Nat. Hist. Misc. Pub. No. 20 (Nov. 2): 1-224, Pis. 1-11, Figs. 1-87. Miles, Charles D. 1958. The Family Succineidae (Gastro- pods: Pulmonata) in Kansas. Univ. Kans. Sci. Bull. 38, Pt. 2, No. 24 (Mar. 20): 1499-1543, PI. 1, Figs. 1-8. Pilsbry, Henry A. 1948. Land Mollusca of North America. (North of Mexico). Acad. Nat. Sci. Philadelphia Mon. No. 3, Pt. 2: xlvii & 521-1113, 585 figs. Yearbook of Agriculture. 1941. Climate and Man. United States Department of Agriculture, U.S. Government Printing Office, Washington, D.C.: v-xii and 1-1248. A NEW SPECIES OF CORALLIOPHILA (GASTROPODA: CORALLIOPHILIDAE) FROM SOUTHEASTERN POLYNESIA Harald A. Rehder Smithsonian Institution Washington, DC 20560 ABSTRACT Coralliophila latilirata is described as new from southeastern Polynesia and compared with C. bulbiformis Conrad (1837). The receipt from M. Jean Trondle of La Force, France, of numerous specimens of a species of Coralliophila from the shores of Anaa Atoll in the Tuamotus, called my attention forcefully to the distinctness of a species which I had collected earlier in French Polynesia, Pitcairn, and Cook Islands, but only in single lots or as fragments. A careful comparison of material of this species with that of C. bulbi- formis Conrad (1837) has revealed not only its distinctness, but also that it is found only in a rather limited area. Coralliophila latilirata, new species Figs. 1-3 Diagnosis: Shell of moderate size, 15-30.75 mm in length, globose to broadly ovate, with numerous crowded, broad, scabrous, flattened spiral cords; aperture deep lavender to pale pur- ple, occasionally white. It is close to bulbiformis Conrad, (1837) but is more inflated, with a lower spire, and broad, crowded, flattened, spiral cords. Range: Southern Cooks, western Austral Islands, Society Islands, Tuamotus, and Pitcairn Group (Fig. 4). Description: Shell stout, thick-shelled, globose to broadly ovate, white, adults from 15 to 30.75 mm in height, width from 70% to 92% of height. Protoconch polygyrate, conical, pinkish, about 4% whorls; first whorl apparently smooth (par- tially-broken off), following whorls with a nodu- lose spiral keel below a sloping shoulder with axial riblets which are somewhat prosocline to opisthocyrt'; a second keel gradually forms above the main keel resulting in the last 11/5 protoconch whorls bearing two keels made nodulose by the axial riblets. Postnuclear whorls about 6 (earliest whorls generally worn or covered with calcareous deposit), early ones amewhat inclined forward to curved backwards" -Editor. 98 THE NAUTILUS October 31, 1985 Vol. 99(4) FIGS. 1-3. Cnnilliiiphiltt Ititilirata n. sp. 1 and 2 apertural and top views of the holotype, USNM 731531, height 25.22 m. 3, apertural view of paratype, USNM 845460, height 30.78 mm. FIG. 4. Map showing distribution of Coralliaphila latiliralu n. sp. (circles), and Coralliophila buMfornns Conrad (stars). strongly carinate, with four broad lirae, finely scalloped, separated by narrow grooves and crossed by broad rounded axial ridges, render- ing the surface of the whorls wavy; in later whorls the axial ridges become broader and lower, and the spiral ridges more irregularly nodose, or flattened, the separating grooves usually very narrow; the penultimate whorl generally with five spiral ridges; body whorl evenly convex, with about 17 irregularly flat- tened ribs that are axially and densely lamellate; the lamellae generally fused together especially on the prosocyrt axial ridges that number thir- teen on the body whorl of the holotype. but may be fewer and broader on other specimens; in worn specimens the axial lamellae that compose Vol. 99 (4) October 31, 1985 THE NAUTILUS 99 the broad spiral lirae may be more or less obscure due to fusion and some erosion. Aper- ture oval, ending anteriorly in a short to moderately long, curved, narrowly attenuated canal; outer lip made finely crenulate by the ends of the external spiral ridges; columella and interior of aperture deep- to pale-lavender, (light grayish purplish red to grayish purplish red: Kelly & Judd, 1965); a strong lamellose fasciole, surrounding a broad to moderately narrow false umbilicus, terminates in the end of the siphonal canal. Habitat: Host unknown. Found alive under and near coral in 40-55 ft. and dredged in 50-56 fathoms. Found in stomachs of fish (Coris aygula) caught in 50-100 ft. Type Locality: Oeno, Pitcairn Islands. Material: Holotype: lagoon, northshore, in 1-6 ft. on hard pan bottom, Oeno, Pitcairn Islands, collected by H. A. Rehder, 18 December 1970 (USNM 731531). Paratypes-COOK ISLANDS: W. of Avatiu, Rarotonga in 45 m (USNM 732270); E of Avarua, Rarotonga, in 25 m (USNM 732262); AUSTRAL ISLANDS: NW of Moerai, Rurutu, in 40-50 m (USNM 732217); north coast, Tubuai, 25 m (USNM 732294); SOCIETY ISLANDS: E side Taunoa Pass, Arue, Tahiti (USNM 668779); TUAMOTUS: NW side Puka Puka (USNM 789879); NW end of lagoon, Anuanuraro (USNM 725347); dead on beach, Anaa (USNM 845460; Colin. Trondle); dead on beach, Raroia (USNM 697956, 697685, 698743). PITCAIRN ISLANDS: off NW corner, in 100-124 m Pitcairn (USNM 789442); off Boun- ty Bay in 15-16.7 m Pitcairn (USNM 731663); W of Bounty Bay, in 30 m (USNM 731831); off Christian's Point, in 15 m (USNM 731765). The two lots from the Cook Islands, the lot from Rurutu, and two of the lots from Pitcairn (USNM 731831, USNM 731765) all consist of fragments found in the gut of specimens of the fish, Coris aygula, speared at the depths indicated. Measurements (mm): USNM 731531 holotype Trondle Colin, paratype USNM 731663 paratype Trondle Colin, paratype Trondle 789453 paratype Trondle 725347 paratype USNM 789879 paratype height width 25.22 20.18 30.75 25.05 21.83 20 26 19.18 16.85 18.08 14.64 16.32 14.34 15.05 13.05 Twenty-five specimens were measured and found to range between 30.75 to 15.05 mm in height and 25.05 to 13.05 mm in width; the average height is 21.72 mm and the average width is 18.14 mm. Etymology: From the Latin, meaning "with broad ridges." Discussion: This species is closest to Corallio- phila bulbiformis Conrad, 1837, but is less elevated, with a low broad spire with flattened whorls, the spiral lirae less numerous, broader, flattened, and made nodulose by more or less worn lamellae, and the axial ribs lower, less prominent than in most specimens of bulbi- formis. Good illustrations of C. bulbiformis Conrad may be found in Cernohorsky 1978 (pi. 21, fig. 4) and Kira, 1962 (p. 68, pi. 26, fig. 6). C. bulbi- formis is identified as C. costularis Lamarck, 1816, by Salvat and Rives, 1975 (p. 310, fig. 190), but the latter is a narrower, fusiform species that is found from East Africa to the Ryukyus. Similarly, C. bulbiformis is synony- mized by Kay in her Hawaiian Marine Shells (Kay, 1979, p. 255, pi. 90B) under C. erosa (R(')ding), but an examination of the description and figures in Chemnitz on which Roding based his name shows that erosa is the species that Kay describes and figures (Kay, 1979, p. 255, fig. 90A) under C. dorbignyana (Petit, 1851), a junior synonym of erosa. Coralliophila bulbiformis Conrad varies con- siderably in shape, from rather elevated with strongly convex, more or less angled whorls with consequently indented sutures to ovate species with only slightly convex whorls and less indented whorls. The latter form is common in the Hawaiian Islands, while the Marquesan specimens are more elevated with convex whorls, as are most of those in the rest of the range of the species. It is a distinct species, and not a subspecies of C. erosa, as Abbott and Dance (1982, p. 155) cite it. This new species is restricted, as far as we now know, to the Cook Islands and French Poly- nesia, including the Pitcairn Islands (Fig. 4). It has however not been found in the Marquesas, where C. bulbiformis occurs, or in Rapa. C. bulbiformis is found from the Ryukyus and Philippines eastward to Hawaii, the Marquesas Islands, Samoa and New Caledonia. ion THE NAUTILUS October 31, 1985 Vol. 99(4) LITERATURE CITED Abbott, R. Tucker and S. Peter Dance. 1982. Compendium oj'Si'iishrlls. New York, 410 pp. Cernohorsky, Walter 0. 1978. Tropical Pacific Marine Shells. Sydney: New York, 352 pp. Conrad, T. A. 1937. Descriptions of new marine shells from upper California, collected by Thomas Nuttall, Esq. J. Acad. nat. Sci. Philadelphia 7:227-268, pi. 17-20. Kay, E. Alison. 1979. Hawaiian Marine Shells. B. P. Bishop Museum Spec. Publ. 64(4), 671 pp. Kelley, K. L. and D. B. Judd. 1965. The ISCC-NBS Method of Designating Colors and a Dictionary of Color Names. Nat. Bur. Standards Circular 553, 163 pp. Kira, T. 1962. Shells of the Western Pacific in Color. Osaka, 224 pp. Sal vat, Bernard and Claude Rives. 1975. Coquillages de Polynesie. Papeete, 391 pp. NATIVE FRESHWATER MUSSELS (UNIONACEA) AS FOULING AGENTS IN ELECTRICAL GENERATING PLANTS Raymond W. Neck Texas Parks and Wildlife Department 4200 Smith School Road Austin, TX 78744 ABSTRACT The occurrence of native freshwater mussels (Unionacea) as fouling agents in the water supply system of an electrical-generating plant is reported. Details of the reported problem and discussion of the likelihood of similar occurrences in additional generating plants are presented. While the Asiatic clam, Corbicula fluminea, is well-known as a fouling agent in electrical gen- erating plants (Mattice, 1977; Smithson, 1981), native unionids have not been implicated in similar situations. Absence of unionids in water distribution systems has been attributed to lack of byssus attachment (see Ingram 1953). Herein I record an example of both Corbicula and native unionids as fouling agents in a cooling water supply main for a lignite-fired electrical generating plant. The purposes of this study were (1) to understand factors significant in this fouling example and (2) to determine if this was an isolated incident or a forerunner of future problems at other power plants. Alcoa Lake is a 5972-hectare reservoir located 11km southwest of Rockdale, Milam Co. , Texas. The impoundment was created in 1953 on Sandy Creek, a tributary of East Yegua Creek in the Brazos River drainage. The limited surface runoff water is supplemented by an aqueduct which transports water approximately 20.5 kilo- meters from the Little River, also in the Brazos drainage. The unionids reported below probably originated from the Little River, although some stocking of fish has occurred in Alcoa Lake. Jule Frankeny of International Generating Corporation, operator of the Sandow Power Plant at Alcoa Lake, informed me that a number of clams had been forced under pressure in August 1983 from a service line (off the supply main) which had been partially blocked. Inspec- tion of recovered clams revealed Anodonta grandis, Cyrtonaias berlandieri and Corbicula fluminea; all three species have been reported from the Brazos drainage (Strecker 1931; Fontanier 1982). These clams were recovered from a 14-inch diameter pipe located four feet below ground surface. To reach this pipe, the individuals recovered had passed through an initial traveling screen (12.8 mm mesh), large pump, booster pump (19.5 mm bore), and another strainer (4.8 mm mesh). Two water supply mains transport water from Alcoa Lake to the Sandow plants. Both mains are of equal size (initially 78" diameter), but one main supplies two plants while the second only supplies one plant (a planned fourth plant was Vol. 99 (4) October 31, 1985 THE NAUTILUS 101 never built). Unionids were found only in a ser- vice line off the second main where decreased water velocities apparently allowed sediment and clams to accumulate to a degree that water flow was eventually restricted. A typical recovered A. grandis shell was 127 mm in length and 72.2 mm in height. This "long, low" phenotype corresponds to the nominate variety. The shell is highly polished, especially on the older part of the shell. Dark rings may represent annuaj growth rings which are gen- erally faint to absent on most Texas shells. Ring production could be due to differences in growth rate due to variations in water temperature and/or food supply. Total number of rings is ten. Cyrtonaias berlandieri from this supply main were small and rather thick-shelled but ap- peared similar to examples from surface water populations from central Texas. Nacre color was light pinkish purple; typical shell height and length was 73.0 mm and 51.0 mm, respectively. Corbicula fluminea shells were small with the largest measuring 28.45 mm in length; all shells were of the "white morph." The only similar example recorded in the liter- ature was by Button (1900). Two examples of Margaritifera margaritifera var. falcata which were collected in a water tunnel near Santa Cruz, California. The shells were found 700 feet from the mouth of the tunnel at a depth of 300 feet. Button (1900) did not state that the ex- amples were alive, but he described the shells as "unusually large and thin, the nacre being richly colored." Occurrence of unionids in water lines of an electrical generating plant raises questions concerning the likelihood of these clams becom- ing major problems in such plants. The exist- ence of this problem at the Sandow complex could be significant because these plants were the first lignite-fueled electric generating units in Texas (Espey, Huston and Associates 1983: 60). Sandow #1 and #2 went on line in 1953 with Sandow #3 becoming operational in 1954. Exist- ence of clams only in the line servicing #3 indicates that the occurrence of unionids as a fouling agent in electric generating plants prob- ably will be a minor problem. The passage of young unionids through the screening mecha- nisms is likely to be a low probability event, especially in contrast to passage of minute larval forms of Corbicula fluminea. Survival of young unionids which do pass through these screens is unlikely except in those pipes with low velocity flows which do not exceed appropriate entrainment velocities. I thank Jule Frankeny and Pete Goggin for supplying the clams and information on the power plants. LITERATURE CITED Button, F. L. 1900. Unionidae in a tunnel. The Nautilus 13:130. Espey, Huston and Associates, Inc. 1983. Impacts of lignite development of Texas. Texas Energy & Natural Resources Advisory Council, EDF-091:l-89. Fontanier, C. E. 1982. The distribution of Corbicula (Bivalvia: Corbiculidae) in the Brazos river system, Texas, 25 August - 12 November 1980. Texas J. Sci. 34:5-15. Ingram, W. M. 1956. Snail and clam infestations of drinking- water suppliers. J. Arner. Water Works Assoc. 48: 258-268. Mattice, J. S. 1977. Interactions of Corbicula sp. with power plants. Pp. 119-138, Proc, First International Corbicula Symposium (J. C. Britton, ed.), Texas Christian Univ. Research Foundation, Fort Worth, 313 pp. Smithson, J. A. 1981. Control and treatment of Asiatic clams in power plant intakes. Proc. Amer. Power Con- ference 43:1146-1151. ILLUSTRATED CATALOGUE OF LATIAXIS AND ITS RELATED GROUPS FAMILY CORALLIOPHILIDAE By Dr. Sadao Kosuge Expected U.S. availability: November, 1985 Most complete coverage of the family Coralliophilidae. Over 200 species illustrated in 24 color and 26 B/W plates, including many holotypes. Brief description, synonyms and geographical distribution for each species are covered in 50 pages of text in English. Paperbound, 7"x 10". You may order from your favorite book dealer or send $22.50 for your copy to Donald Dan, 2s649 Avenue Normandy East, Oak Brook, IL 60521. Price includes domestic U.S. postage. (For foreign orders, add $2.00 for seamail and $12.00 for airmail). 102 THE NAUTILUS October 31, 1985 Vol. 99(4) TERAMACHIA DUPREYAE NEW SPECIES, FROM OFF WESTERN AUSTRALIA (GASTROPODA: VOLUTIDAE) William K. Emerson Department of Invertebrates American Museum of Natural History New York, NY 10024 ABSTRACT Teramachia dupreyae, a new species from deep water 200 miles NW of Broome, Australia, is described and compared with related species of the volutid subfamily Calliotectinae. In addition to this newly described taxon, the following species are recognized in the genus Teramachia: tibiaeformis Kuroda, 1931, dalli (Bartsch, 1942), smithi (Bartsch, 1942), johnsoni (Bartsch, 1942), mirabilis (Clench and Aguayo, 1941), and shinzatoensis MacNeil, 1961. Through the kind offices of Robert and Dorothy Janowsky, proprietors of Mai de Mer Enterprises of West Hempstead, New York, the presence of recently obtained specimens of this interesting discovery were brought to my atten- tion. I am pleased to describe this new western Australian volute in honor of Constance Duprey of Nashville, Tennessee, who generously sub- mitted her specimens for study and donated the holotype to the American Museum of Natural History (AMNH). A total of seven species, including the new taxon described herein, are recognized in the genus Teramachia at the present time. Five liv- ing and one extinct species are known from the western Pacific. A single extant species is reported from the western Atlantic. The previously known species-group taxa referable to Teramachia are listed in sequence of publication: 1. Teramachia tibiaeformis Kuroda, 1931, pp. 45-47, figs. 2, 3; Kuroda and Habe, 1950, pp. 36, 37, pi. 5, fig. 1, text fig. 5 (operculum), "Tosa in 100 fms." [182 meters]; Habe, 1952, p. 132, fig. 12 (radula); Azuma, 1960, p. 48, pi. 2, fig. 9, off Tosa, in 182 meters; Kira, 1962, p. 92, pi. 33, fig. 4 (illus. in color), "Honshu and southwards, rare- ly found at 100-150 fathoms depth" [182-274 meters); Shikama, 1963, p. 97, pi. 79 (illus. in color), Hyuga, Japan; Weaver and duPont, p. 179, pi. 76 E, F (illus. in color), text fig. 41b (operculum); Abbott and Dance, 1982, p. 224 (illus. in color). Type locality: "< H'f Kii". [Honshu, Japan]. The type species of Teramachia Kuroda, 1931. This well-known, small species (length to 90 mm) seems to be restricted to southern Japanese waters. The holotype is in The Academy of Natural Sciences of Philadelphia. 2. Teramachia mirabilis (Clench and Aguayo, 1941), pp. 177, 178, pi. 14, fig. 2; Clench and Turner, 1964, p. 177, pi. 114 (holotype); Weaver and duPont, 1970, p. 178, pi. 76 A," B (holotype, illus. in color). Type locality: "off Matanzas, Matanzas Prov., Cuba,... in 289 fathoms [528 meters]". The type species of Howellia Clench and Aguayo, 1941. 3. Teramachia dalli (Bartsch, 1942), pp. 10, 11, pi. 2, figs. 1 (operculum), 4; Weaver and duPont, 1970, p. 177, pi. 75 E, F (holotype, illus. in color), text fig. 41a (operculum); Lan, 1980, p. 63, pi. 25, figs. 55, 55a, "SW off Taiwan"; Bouchet, 1981, p. 10, illus., NW of Mindoro, Philippines, in 680-770 m; Abbott and Dance, 1982, p. 224 (holotype, illus. in color); Okutani, 1983, p. 10, pi. 33, fig. 5, "Taiwan"; Wells, 1983, p. 5, illus., off Port Hedland, northwest Australia, in 376 meters. Type locality: "off Cape Santiago, Luzon, [Philippines], in 394 fathoms [720 meters]." The type species of Prodallia Bartsch, 1942. This stout but thin shelled species attains 175 mm in length. The prominent suture is deeply grooved and off-set by regular and evenly spaced ribs, which are ter- minally cuspate at the summit. The periostra- cum on fresh specimens is a blackish brown. 4. Teramachia smithi (Bartsch, 1942), p. 11, Vol. 99 (4) October 31, 1985 THE NAUTILUS 103 pi. 2, fig. 5; Weaver and duPont, 1970, pp. 178, 179, pi. 76 C, D (holotype, illus. in color); Greene, 1975, p. 12, illus., "10 miles southeast Taghilaran, Bono], Philippines, trawled alive"; Clover, 1978, pp. 60, 61 (illus. in color), "Off Boho, Philippines, in 200 meters"; Abbott and Dance, 1982, p. 224 (holotype, illus. in color). Type locality: "off Balicasag Island, Bohol [Philippines], in 439 fathoms [802 meters]". This large shell (length 173.5 mm, Duprey coll. A429) is characterized by the narrow spire, inflated body whorl, with a wide aperture and a widely flaring outer lip. The periostracum is a tannish brown. 5. Teramachia johnsoni (Bartsch, 1942), p. 12, pi. 2, fig. 3; Weaver and duPont, 1970, p. 178, pi. 75 G, H (holotype, illus. in color); Rehder, 1972, p. 8, figs. 3, 7; Lan, 1980, p. 63, pi. 25, figs. 54, 54a, "SW off Taiwan" (not T. tibiae- formis); Okutani, 1983, p. 10, pi. 33, fig. 4, "Cebu, Philippines" (not T. tibiaeformis), fig. 6, "South China Sea" (not T. smithi) and fig. 7, "Taiwan". Type locality: "3V2 miles NW of Cagayan Island, [Philippines], in the northern Sulu Sea, in 344 fathoms [628 meters]," fide Rehder, 1972, p. 8. Originally described on the basis of an immature specimen, Rehder (1972, pp. 8, 9, figs. 3, 7) subsequently described an adult specimen of this narrowly and elongately fusiform species, which is known to attain 145 mm in length. The light brown periostracum covers a grayish to tannish shell with the suture stained a darker gray. The outer lip is strongly arcuate. Populations from the Formosa Strait were afforded subspecific recognition by Rehder; see T. j. williamsorum, infra citato. 6. Teramachia shinzatoensis MacNeil, 1961, p. 96, pi. 9, fig. 1; Rehder, 1972, p. 8, figs. 5, 6 (holotype). Type locality: "Shinzato tuff member, [Neogene, Okinawa, Japan]". This small (length 69.8 mm), Mio-Pliocene fossil is compared with T. johnsoni by MacNeil (1961, op. tit.) and Rehder (1972, op. tit). 7. Teramachia johnsoni williamsorum. Rehder, 1972, pp. 8, 9, figs. 1, 2, 4; Abbott and Dance, 1982, p. 224 (holotype, illus. in color). Type locality: "30 miles south of Tung-Chiang, Taiwan, in 150 fathoms [274 meters]". All the specimens I have examined of this form are from the Formosa Strait. Abbott and Dance (op. cit.) consider this taxon to be an infrasubspecific form of T. johnsoni Bartsch. The available data suggest that Rehder's taxon is conspecific with T. johnsoni. As in the new species, shell dimor- phism is expressed by a stout form (Rehder, 1972, figs. 1, 4, holotype of T. j. williamsorum) and a slender form (Rehder, 1972, figs. 3, 7). Family Volutidae Fleming, 1822 Subfamily Calliotectinae Pilsbry and Olsson, 1954 Genus Teramachia Kuroda, 1931 Teramachia Kuroda, 1931, p. 45. type species by monotypy, Teramachia tibiaeformis Kuroda, 1931, pp. 45-47, figs. 2, 3, off Kii, Japan. Howellia Clench and Aguayo, 1941, p. 177, with its type species by monotypy, Howellia mirabilis Clench and Aguayo, 1941, pp. 177, 178, pi. 14, fig. 2, off Cuba, in 285 fathoms [520 meters], was based solely on the holotype, with- out knowledge of the soft parts and operculum, and was provisionally placed in the Fasciolari- idae. Clench and Turner (1964, p. 178, pi. 114) subsequently assigned Howellia to the Voluti- dae, subfamily Calliotectinae, following Pilsbry and Olsson (1954, p. 19). Clench and Turner (op. tit.) noted the close resemblance in shell mor- phology of the type species to the genus Tera- machia. The western Atlantic T. mirabilis does recall examples of T. tibiaeformis from Japan, but differs in having the strong axial sculpture carried on to the body whorl. A more precise systematic assessment of Howellia must await knowledge of the soft parts and the radular characters of the type species. Prodallia. Bartsch, 1942, p. 10, with its type species by original designation, Prodallia dalli Bartsch, 1942, p. 10, off Luzon, Philippines, ex- Bartsch ms., was introduced in a 20-page brochure circulated at a banquet in honor of William Healey Dall, on April 21, 1915. Because the banquet brochure was not available to the general public, these taxa were not nomencla- turally available until 1942 when Bartsch first validly proposed the names. Kuroda (1931, p. 47) provisionally placed the genus Teramachia in the Volutidae largely on the basis of shell and opercular morphology. This familial assignment was retained by Kuroda and Habe (1950, p. 36). Subsequently, Habe (1952, p. 132, fig. 12) figured the rachidian teeth of T. tibiaeformis, without comment. 104 THE NAUTILUS October 31, 1985 Vol. 99 (4) Pilsbry and Olsson (1954, p. 19) included Ti nimtirhiti (with ['nxlallin in synonymy) in their volutid subfamily Calliotectinae. They il- lustrated a tricuspid rachidian tooth (Pilsbry and Olsson, 1954, pi. 3, fig. 16) of the type species of Calliotectum Dall, 1890, which has rachidian dentition similar to that illustrated by Habe (1952, op. tit.) for T. tibiaeformis. The radular and opercular characters of Teramachia tibiaeformis strongly indicate placement of this genus in the Volutidae (Weaver and duPont, 1970, p. 176; Render, 1972, p. 7; Cernohorsky, 1973, p. 127; Emerson and Old, 1979, p. 11; Quinn, 1981, p. 73), although some authors have assigned Teramachia to the Turbinellidae (olim Xancidae) largely on the basis of shell mor- phology (Bayer, 1971, p. 195; Abbott and Dance, 1982, p. 224). Rehder (1972, p. 7) reported the presence of two oblique folds on the columella of immature specimens of T. tibiaeformis and T. johnsoni, which become obscure in the adult stage. These folds are weakly developed. None of the speci- mens I have examined of the species herein referred to Teramachia possesses columellar plications. Taxa with columellar plaits, which were previously assigned to the calliotectine volutes, are now placed in the Turbinellidae (Rehder, 1967, 1972; Cernohorsky, 1973; and Quinn, 1981). This includes Prodallia barthelowi Bartsch (1942, pp. 12, 13, fig. 2) from the Philippines. The new species of Teramachia is one of many new or otherwise interesting deep-water species recently obtained by shrimp boats trawling off the northwest coast of Australia; see Davis and Ward (1984). Kosuge (1985) lists and illustrates some of these findings in a preliminary report on the mollusks. Teramachia dupreyae new species Figs. 1-8 Teramachia aff. T. dalli (Bartsh [sic], 1942), Slack-Smith, 1980. p. 1, illus., "SW of Cape Leeuwin, W. Australia, in 488-496 m." Not Teramachia dalli (Bartsch, 1942). 7'i in much in johnsoni (Bartsch. 1942), Kosuge, 1985, p. 58, pi. 23, fig. 1 , off the northwestern coast of Australia. Not /' rii machia johnsoni (Bartsch, 1942). Diagnosis: Shell large for genus, exterior a tannish white, aperture a glossy white, suture and anterior portion of columellar wall stained a brownish lavender; periostracum inconspicuous, thin, yellowish buff. The darkly colored sutural line against the light color of the shell im- mediately distinguishes this elegant volute from its congeners. Description: Shell large, attaining 195+ mm in length, slenderly elongate fusiform. Proto- conch missing; remaining whorls of holotype IOV2. Lined suture narrow, canaliculate on early whorls, with axial ribs, numbering 33 to 37 on last completely ribbed whorl; ribs obsolete on lower portion of antepenultimate whorl and wanting on the penultimate and body whorls, on which irregular growth lines occur. Aperture elongate, outer lip flaring, edge thin; anal sulcus with narrow sinus at juncture with suture; anterior siphonal canal widely open; parietal lip thinly glazed; columella without plications, and weakly folded. Operculum typical for the genus (Kuroda and Habe, 1950, p. 46, fig. 5). Soft parts not preserved. Color, see Diagnosis above. Shell dimorphism is characterized by slender individuals (holotype, here illustrated, figs. 7, 8 and paratypes C and D) and a shorter, inflated form (paratype A, here illustrated, figs. 3, 4). Measurements: Holotype, 185 mm in height, 46 mm in width; paratype A, 145 mm in height, 48.5 mm in width; paratype B, 153 mm in height, 44 mm in width; paratype C, 192 mm in height, 48.7 mm in width; paratype D, 197 mm in height, 42.5 mm in width; paratype E, 184.2 mm in height, 42.8 mm in width; and paratype F, 166 mm in length, 39.9 mm in width. Type locality: 200 miles NW of Broome, Australia off McDonnell Reef in 400 meters, February 1985. Type specimens: holotype, AMNH 213477 (figs. 7, 8); paratypes A (figs. 3, 4, 6) and B (figs. 1, 2, 5) and C from type locality, Constance Duprey collection; paratype D, AMNH 213438, here transferred to the Western Australian Museum, Perth, from 200 miles NW of Broome, between Rowley Shoals and Scotts Reef, in 450 meters; paratype E, AMNH 214367, off Broome, in 184 meters; and paratype F, AMNH 214368, off Port Hedland, NW Australia, in 166 meters. Remarks: Of the nominal species of Tera- machia, the present species most closely resem- FIGS. 1-8. Teramachia dupreyae new species. 1, 2, Paratype B. 3, 4, Paratype A. 5, 6, enlarged early whorls, 5, Paratype B; 6, Paratype A. 7. 8, Holotype, AMNH 213477. 1-4, 7, 8 approximately x 2h; 5, 6 approximately x 1.5. Vol. 99 (4) October 31, 1985 THE NAUTILUS 105 106 THE NAUTILUS October 31, 1985 Vol. 99 (4) bles in general appearance T. johnsoni, which differs in having the body whorl and penulti- mate whorl purplish gray, the early whorls yellowish white or white, and the outer lip a grayish purple with a brownish margin inside the whitish edge of the lip (Rehder, 1972, p. 9). In T. tibiaeformis, a dark spiral band appears below the suture on the body whorl and penulti- mate whorl of some specimens (cf. Abbott and Dance, 1982, illus. on p. 224). In T. dupreyae new species, the spiral coloration is restricted to a thin brownish lavender line within the suture (see figures herein). Specimens of the new species from the conti- nental slope off northwest Australia were previously recorded and illustrated by Slack- Smith (1980, p. 1), who compared her specimen with Teramachia dalli (Bartsch), and by Kosuge (1985, pi. 23, fig. 1), who referred his to T. johnsoni (Bartsch). Teramachia dalli is also reported from off the northwest coast of Australia in moderate depths (Wells, 1983, p. 5, illus.); Kosuge, 1985, p. 59, pi. 23, fig. 6). An additional specimen of T. dalli was trawled, in March 1985, off McDonnell Reef, 200 miles NW of Broome, Australia and was examined by me courtesy of Constance Duprey. This dark- colored species differs from the present species in the presence of stronger, axial ribs, which ex- tend to upper part of the body whorl, and in the development of a deeply and broadly channeled suture. Acknowledgments In addition to Constance K. Duprey and Dot and Bob Janowsky, I should like to thank my AMNH colleagues for their contributions to this study: Walter E. Sage III for advice and techni- cal assistance, Susan Klofak for specimen preparation, Peter J. Harries for the photo- graphy, and Stephanie Crooms for word- processing the manuscript. Dr. Richard S. Houbrick of the National Museum of Natural History, Smithsonian In- stitution, and Mr. Russell H. Jensen of the Delaware Museum of Natural History kindly lent me specimens from their respective collec- tions for study. Mrs. Gloria Scarboro of Indian Harbour Beach, Florida, generously donated Paratype D to the collection of the AMNH. Mr. Donald H. Y. Dan of Oak Brook, Illinois, and Mr. John Landin of Palos Park, Illinois, kindly provided specimens for study. LITERATURE CITED Abbott, R. T. and Dance, S. P. 1982. Compendium of Sea- shells, New York, 411 pp., illus. Azuma, M. 1960. A catalogue of the shell-bearing Mollusca of Okinoshima, Kashiwajima and the adjacent area (Tosa Province) Shikoku, Japan., 102 + 17 pp., 5 pis., 2 text figs. Bartsch, P. 1942. Some deep-sea Philippine volutids. The Nautilus 56(1):9-13, pi. 2. Bayer, F. M. 1971. New and unusual mollusks collected by R/V John Elliott Pilsbury and R/V Gerda in the tropical western Atlantic. Bull. Mar. Sci. 21(l):lll-236, figs. 1-72. Bouchet, P. 1981. Oceanographic expedition at Lubang Island, 1980. Carfel Philippine Shell News 3(2):3, 4 and 10, 10 figs. Cernohorsky, W. O. 1973. The taxonomy of Benthovoluta hilgendorfi (Von Martens) and allied turbinellid genera. (Mollusca: Volutacea). Rec. Auckland Inst. Mus. 10: 123-131, 16 figs. Clench, W. J. and Aguayo, C. G. 1941. Notes and descrip- tions of new deep-water Mollusca obtained by the Harvard-Havana Expedition off the coast of Cuba. IV. Mem. Soc. CubanaHist. Nat. 15(2):177-180, pi. 14. Clench, W. J. and Turner. R. D. 1964. The subfamilies Volutinae, Zidoninae, Odontocymbiolinae, and Calliotec- tinae in the western Atlantic. Johnsonia 4(43):129-180, pis. 80-114. Clover, P. W. 1978. Smith's volutas. Shell Collector (Ft. Lauderdale, Florida), no. 1, pp. 60, 61, illus. Davis, T. L. 0., and Ward, T. J. 1984. CSIRO finds two new scampi grounds off the North West shelf. Australian Fisheries 43(8):41-45. Emerson, W. K. and Old, W. E., Jr. 1979. Scaphella con- toyensis, a new volutid (Gastropoda) from east Mexico. The Nautilus 93(1):10-14, 7 figs. Greene, J. 1975. A long-lost' volute. Hawaiian Shell News, 23(12):12, 1 fig. Habe, T. 1952. Pholadomyidae, Clavagellidae, Pandoridae. Juliidae and Condylocardiidae in Japan. Illustrated Catalogue of Japanese Shells, No. 18, pp. 121-132, pi. 18, 28 text figs. Kira, T. 1962. Shells of the Western Pacific in Color. Osaka, i-ix + 1-224, pis. 1-72. Kosuge, S. 1985. Noteworthy Mollusca from north-western Australia (1), (Preliminary report). Bull Inst. Malac. Tokyo 2(3):58-59, pis. 22, 23. Kuroda, T. 1931. Two new species of Volutacea. Venus 3(1): 45-49, 3 figs. Kuroda, T. and Habe, T. 1950. Volutidae in Japan. Illus- trated Catalogue of Japanese Shells, No. 5, pp. 31-38, pis. 5-7, 6 text figs. Lan, T. C. 1980. Rare Shells of Taiwan in Color. Taipei, pp. 1-144, 63 pis. MacNeil, F. S. 1961. Tertiary and Quaternary gastropods of Okinawa. U.S. Geol. Surv. Prof. Paper 339 ("I960"): i-iv + 1-148, pis. 1-19, (distributed March 17, 1961). Okutani, T. 1983. World Seashells of Rarity and Beauty. Vol. 99 (4) October 31, 1985 THE NAUTILUS 107 Kawamura Collection. National Science Museum, Tokyo, i-iii + 1-12, 48 pis. Pilsbry, H. A. and Olsson, A. A. 1954. Systems of the Voluti- dae. Bull. Amer. Paleont. 35(152):271-306, pis. 25-28. Quinn, J. F., Jr. 1981. A new genus of Turbinellidae (Gastro- poda: Prosobranchia), with the description of a new species from the Caribbean Sea. The Nautilus 95(2):72-77, 5 figs. Rehder, H. A. 1967. A new genus and two new species in the families Volutidae and Turbinellidae (Mollusca: Gastro- poda) from the western Pacific. Pacific Sci. 21(2):182-187, 1 1 figs. 1972. Some notes on the genus Teramaehia (Volutidae: Calliotectinae). The Veliger 15(1):7-10, 7 figs. Shikama, T. 1963. Selected Shells of the World Illustrated in Color. Tokyo, pp. 1-154, pis. 1-102, 211 text figs. Slack-Smith, S. 1980. New records for the western Austra- lian continental slope. Australian Shell Netvs. Malac. Soc. Australia, no. 32, pp. 1, 2, illus. Weaver. C. S. and duPont, J. E. 1970. Living volutes: a monograph of Recent Volutidae of the world. Delaware Mus. Nat. Hist. Mong. Ser., No. 1, xv + 374 pp., 79 col. pis., 44 figs., 13 maps. Wells, F. 1983. Wonders from the Northwest. Australian Shell News, Malac. Soc. Australia, no. 43, pp. 4, 5, illus. ADDITIONAL COLORADO RECORDS OF ANODONTA GRANDIS GRANDIS SAY (BIVALVIA: UNIONIDAE) Scott J. Herrmann and James R. Fajt Department of Life Sciences University of Southern Colorado Pueblo, CO 81001 Upon first finding Anodonta grandis grandis Say, 1829, in large numbers in the Colorado Fuel and Iron Reservoirs No. 2 and No. 3 near Pueblo, Colorado, in August of 1982, we became concerned about the rarity of them elsewhere in the state. Since the summer of 1982 we have been searching eastern Colorado for viable populations of this freshwater mussel. All the water in C.F.&I. Reservoir No. 3 had to be released by February 1983 so a new water control valve could be installed in the dam before the spring runoff began. As the water level was lowered, thousands of Anodonta grandis grandis became exposed. In February 1983 we transferred 412 adults from the C.F.&I. Reservoir No. 3 to the newly formed Pueblo Reservoir. Statewide news media cover- age of this transplanting operation brought many calls and messages regarding the occur- rence of bivalves elsewhere in eastern Colorado. Each of these notices was investigated. If dur- ing these investigations A. grandis grandis was found, we attempted to collect the largest (in length) and smallest specimens available. In addition, from each site at which A. grandis grandis was found a 1 liter composite (surface to near bottom) water sample was collected and kept on ice in a cooler until our return to the laboratory. In the Water Resources Laboratory of the University of Southern Colorado standard methods were used to analyze the cooled water samples. Atomic absorption spectrophotometric methods were used for the analysis of Na, K, Cu, Mn, Fe, and Zn. Sediment was examined in the field for relative particle size. Burch (1973) indicated the North American range for Anodonta grandis grandis as being throughout the Mississippi-Missouri River drainage. In Colorado Brandauer and Wu (1979) cite only two old records for this species: one from 1911 in Boulder County, 30 miles north of Denver, consisting of 1 specimen; and a second collected 10 October 1915 from Yuma County, a pool in Black Wolf Creek, IV2 miles north and 1 mile west of Beecher Island, consisting of 35 specimens. The large collection from Black Wolf Creek in far eastern Colorado was made by Ellis (1916), who reported they were abundant and tightly embedded in the dense blue clay bottom. On 21 October 1983 we visited the vicinity of Black Wolf Creek described by Ellis (1916) and Brandauer and Wu (1978) and attempted to col- lect living specimens. All we found after search- ing about a mile segment were four shell frag- 108 THE NAUTILUS October 31, 1985 Vol. 99(4) merits of this species. Without more specific in- formation it was impossible to locate the Boulder County site. It is quite possible that Anodonta grandis grandis is now extinct in the two sites reported by Brandauer and Wu (1978). Recently, Wu (1984) reported to us another locality where this species is surviving. The 30 specimens and one valve (University of Colo- rado Museum [UCM] Collection No. 28913) erro- neously identified as Anodontoides ferussa- cianus (Lea) in Brandauer and Wu (1978) p. 48, from Boyd Lake, Larimer County are in fact Anodonta grandis grand is. An additional collec- tion (UCM No. 32168) from Boyd Lake of two specimens and six valves are also A. grandis grandis. Four lentic sites were found to support thriv- ing populations. Two of these sites, C.F.&I. Reservoir No. 2 and No. 3, are new drainage records for Colorado. To date Anodonta grandis grandis has not been reported from the Arkan- sas River drainage in Colorado. These two records probably represent the extreme west- ward extension of the range of this species because only ten miles (16 km) west the Great Plains give way to the foothills of the Wet Moun- tain frontal range. The other two sites, Mayham Lake and Flagler Reservoir, are located in the South Platte and Republican River drainages respectively. The specific geographical and altitudinal data for each of these four sites are indicated in Table 1. All are on the Colorado Great Plains and occur at about the same eleva- tion. If in the past a site had a different name, or is today known by multiple names, all such names have been indicated in Table 1. The range in size (total length) for all living naiads examined from each site were as follows: Flagler Reservoir (85 to 186 mm for 42 speci- mens), Mayham Lake (30 to 160 mm for 80 specimens), C.F.&I. Reservoir No. 2 (19 to 183 mm for 121 specimens), and C.F.&I. Reservoir No. 3 (11 to 192 mm for 534 specimens). We have determined that in the latter two sites this species showed a continuous age structure from one to fifteen years. It appears to us that Anodonta grandis grandis is reproducing and thriving in all four sites. A comparison of the water quality for the four study sites in Table 2 shows all have hard water (171 to 233 mg/L CaC03) that is highly buffered. Trace metals (Fe, Cu, Zn, and Mn) in the dis- solved fraction are all relatively low (<0.2 mg/L) and do not appear to present any toxic prob- lems. Under these conditions Anodonta grandis grandis could be expected to have available suf- ficient calcium carbonate for shell construction. In addition, all the sediments contained varying mixtures of particles from clay to coarse sand. The occurrence of this species in a wide variety TABLE 1. Geographical and altitudinal data for new site records of Anodonta grandis grandis Say in Colorado. Name of reservoi r Elevation ft. a.s.l.* (m a.s.l . ) County Coordinates Local ity River drainage Flagler Res. 4707 (1435) Kit Carson T9S, R50W, S5, 4, 9, 10 34 mi (57 km) E. of Limon Republ ican Mayham Lake (Hidden Lake or Hud Lake) 5281 (1610) Adams T3S, R68W, S6 1 mi (1.6 km) S. of Westmin- ster (N.W. Denver) South Platte C.F.&I. Res. No. 2 (St. Charles Res. No. 2) 4913 (1497) Pueblo T21S, R65W, S34 & 35 9 mi (14.5 km) S. of Pueblo Arkansas C.F.&I. Res. No. 3 (St. Charles Res. No. 3) 4960 (1512) Pueblo T21S, R65W, S33 & 34 and T22, R65W, S3 & 4 9 mi (14.5 km) S. of Pueblo Arkansas *feet above sea level (meters above sea level) Vol. 99(4) October 31, 1985 THE NAUTILUS 109 TABLE 2. Physico-chemical water quality data for four new site records of Anodonta grandis grandis Say in Colorado. All data reported as mg/L except dates, turbidity, pH, and conductivity, "is raw water determination, "not detectible (<0.01 mg/L). Parameter Flager Res. Mayham Lk. C.F.&I. Res. No. 2 C.F.&I. Res. No. 3 Date of water samplinq 21 Oct. 83 6 Sept. 83 14 Feb. 84 3 Mar. 84 Turbidity* (JTU) 38 40 15 10 Total Hdns. (CaC03) 232 171 233 179 Ca Hdns. (CaC03) 120 105 182 121 Mg. Hdns. (CaCCh) 112 56 51 58 Ci 72.5 81.0 11.5 23.5 so4 45 41 35 28 Na 102 117 19 16 K 13.6 18.0 3.0 2.8 Conductivity (jjS ) 870 890 480 370 Fe ND** ND ND ND Cu .005 .005 .003 .003 Zn .012 .006 .014 .014 Mn .005 .160 .006 .006 T-alk* (CaC03) 141 118 138 131 pH* 8.2 8.3 7.3 7.6 of substrates was documented by Clarke and Berg (1959). All four reservoirs support a variety of com- mon warm-water fish: the green sunfish (Lepomis eyanellus), bluegill (Lepomis macro- chirus), pumpkinseed (Lepomis gibbosm), and carp (Cyprinus carpio). In addition, Flagler Reservoir supports a thriving population of largemouth bass (Micropterus salmmdes), and C.F.&I. Res. Nos. 2 and 3 channel catfish (Ictalurus pimetatus), white crappie (Pomoxis annularis), and black crappie (Pomoxis nigro- maculatus). Most of these fish are known hosts for the glochidia of Anodonta grandis grandis. Acknowledgments We are indebted to Dr. John B. Burch, Muse- um of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, for confirming our identifications of Anodonta grandis grandis. We are particularly grateful to Dr. Shi-Kuei Wu, University of Colorado Museum, for criticizing the first draft of this manuscript. We would also like to publicly thank Mr. Bob Paytin of the Colorado Division of Wildlife for assistance with field work. Funds to support this research were provided by the University of Southern Colorado Faculty Research Grant Program and the Colorado Divi- sion of Wildlife. LITERATURE CITED Brandauer, N. and S.-K. Wu. 1978. The Bivalvia of Colorado, Part 2. The Freshwater mussels (Family Unionidae). Natur. Hist. Invent. Colo.. 2:41-60. Burch, J. B. 1973. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. U.S. Environ. Protect. Aq. Biota of Freshwater Ecosystems Ident. Manual 11:1-176. Clarke, A. H. and C. O. Berg. 1959. The freshwater mussels of central New York with an illustrated key to the species of northeastern North America. Cornell Univ. Mem- 367:1-79. Ellis. M. M. 1916. Anodonta douielsi Lea in Colorado. The Nautilus 29:116-119. Wu, S.-K. 1984. Personal conimnniration. 31 May 1984. 110 THE NAUTILUS October 31, 1985 Vol. 99 (4) A 40-WEEK STUDY ON GROWTH OF THE ASIAN CLAM, CORBICULA FLUMINEA (MULLER), IN THE KANAWHA RIVER, WEST VIRGINIA James E. Joy Department of Biological Sciences Marshall University Huntington, WV 25701 ABSTRACT A sample population of Corbicula fluminea individuals maintained in cages was monitored over a 40-week period (12 March to 16 December 1983) to assess growth (in shell length, and overall body weight), percentage of total body weight made up of soft tissues (i.e. "condition index"), and mortality rate. There were vir- tually no increases in length or weight when water temperatures were below 10°C. Noticeable growth began when water temperature reached ~ 14° C. Highest rates of growth (shell length, 0.66 mm/wk; weight, 0.26 gmlwk) occurred when water temperatures were between 2U° and 30° C. "Condition indices" (ranging from a low of 12.6% in June to a high of 21.2% in October) for experimentally caged clams were similar to those found in natural stream clams. Twenty-five of the 300 (8.3%) clams under experimental conditions died. In September 1980, operation of Unit 2 at Arkansas Power and Light's Nuclear One power plant near Russellville had to be shut down because of an extensive invasion of the reactor's emergency cooling system by Asian Clams, Cor- bicula fluminea (Miiller, 1776). The cleanup took 29 days at a cost to AP&L of 15.3 million dollars (Griffin, 1983). After the AP&L case, the Nuclear Regulatory Commission found that 10 other nuclear power plants had experienced bio- fouling problems because of C. fluminea. although not to the extent found in the Arkansas facility (Buel, 1983). The biofouling potential of this clam species prompted the NRC, and the Electric Power Research Institute of Palo Alto, California, to sponsor the Second International Corbicula Symposium at Little Rock, Arkansas (hosted by AP&L and the University of Arkansas) in June of 1983. During those meetings McMahon (1983, pers. comm.) stressed the need for more infor- mation regarding northeastern populations of C. fluminea. Although the present work had begun prior to the symposium, McMahon's com- ments provided an added incentive for the con- ii m of this project assessing the growth of C. fluminea in West Virginia over an extended time period. It should be added that C. fluminea, as an in- troduced species, has become widely dispersed throughout the major drainages of the United States, and that many types of industrial facilities are threatened by large accumulations of this nuisance species. For an account of the spread of this clam the reader is referred to McMahon (1982). Materials and Methods On 5 March 1983, 470 Corbicula fluminea in- dividuals, measuring 9.0 to 15.2 mm in shell length, were collected from Mud River, West Virginia (MG92885315, USGS Topographic Map, Milton Quadrangle, W. Va. 1972) and car- ried to the laboratory at Marshall University in two 20 liter containers. Twenty clams were selected at random, cleaned with absorbent nylon reinforced towels (Fisher Teri® Wipers), measured individually for shell length to the nearest 0.1 mm with vernier calipers, then weighed collectively for total weight. Soft tissues were removed from these clams, blotted dry on another absorbent towel, then weighed. A baseline "condition index" (C. I.) was deter- mined by: c I wet soft tissue weight total weight . mil Vol. 99 (4) October 31, 1985 THE NAUTILUS 111 Both weighings were made on a Mettler Model P1000 balance to the nearest 0.01 gm. The re- maining 450 clams were transferred to an unheated building where they were maintained at water temperatures of 10° to 14°C in a 50 gallon aerated aquarium containing a substrate of sand and gravel to a depth of 8.0 cm. On 12 March 1983 (Day Zero), clams were transported to the field site at the U. S. Army Corps of Engineers Marmet Locks and Dam on the Kanawha River, West Virginia (milepoint 67.7, Kanawha River Navagation Charts, Corps of Engineers, Jan. 1975). Clams were selected randomly and segregated into 15 groups on site. The 30 clams in each group were cleaned then measured individually for shell length as described previously. Clams in each group were then weighed collectively on an Ohaus triple- beam balance for total weight to the nearest 0.1 gm. Mean lengths and weights were recorded for Day Zero. A series of 15 cages, in three floating units (cf. Fig. 1), were used to hold clams. Each group of 30 clams was placed in a separate cage, along with a sand and gravel substrate approximately 6.0 cm deep. Each unit of five cages was then lowered into the river and secured to the outer lock wall (away from barge traffic) with an ap- propriate length (~ 3 meters) of 3/8 inch dia- meter nylon rope. Surface water temperature was recorded for Day Zero, and on each collec- tion date (Table 1; Fig. 2A) thereafter. After two weeks the floating unit with Cage #1 was pulled from the river and all living clams retrieved from that cage. These clams were cleaned and divided into two equivalent length subgroups. Mean lengths and weights were determined for each subgroup. One subgroup (open triangles of Fig. 2B) was returned to the laboratory for a C. I. determination. Clams of the second subgroup (open squares of Fig. 2B) were replaced in the cage and lowered back into the river. After an additional two weeks at prevailing temperatures, clams in the second subgroup of Cage #1 were retrieved, cleaned, and measured again for length and weight then returned to the lab for a C. I. determination. The procedure for handling clams in subse- quent weeks (collection schedule, Table 1) for Cages #2 thru #10 was the same as described for Cage #1. Clams collected on those dates in nor- mal type of Table 1 (symbolized as closed circles in Fig. 2B and diagonal line bars in Fig. 2C) yielded data pertaining to increases in length, and weight, from Day Zero. Thus as the experi- mental time period increased, measured growth took place over widely varying temperature con- ditions (Fig. 2A). Clams retrieved on those dates in boldface type of Table 1 (symbolized as closed squares in Fig. 2B and dark bars of Fig. 2C) yielded data on length, and weight, increases over a two week period only, at relatively con- stant temperature ranges. This procedure also permitted a C. I. determination every two rope hole styrofoam floatation collar upper and lower bars hold collar aluminum screen along both sides of unit side wall to retain substrate FIG. 1. Line drawing (not to scale) of field unit with five cages. 112 THE NAUTILUS October 31, 1985 Vol. 99 (4) MIAN W T. gin SHELL LENGTH mn — — si s> O ui o % V % b 1 V < b 1 V b 1 p * { h'.WWiM c Ffnifinin I ■WWWW1-' £ II I I I IIIIIITfffl LI I 1 1 1 1 III I 1 1 1 1 1 Lwwwww. kWWWWWi, iiiiii vrrvrrmvm . | ' lo _l^_ TEMP C 0 o 1 I I •— 0-« * 2j _1»>J !■■■ FIG. 2A. Surface water temperatures recorded within cage : fit' collection. FIG. 2B. Opel] circles = mean SL (shell length) on Day Zero. Closed circles = mean SL after experimental period (in weeksi designated on X-axis. Open triangles = mean SL of lab subgroup, open squares = mean SL of field subgroup. I squares = mean SLof field subgroup after additional two week period in field. Vertical lines = SL range. Numbers a ■ in symbols - mean SL increase for period indicated along X-axis. Numbers below vertical lines = sample size of living clams. FIG. 2C. Open bars = mean weight on Day Zero. Diagonal line bars = mean weight after experimental period. Stippled bars = mean weight of field subgroup. Dark bars = mean weight of field subgroup after additional two week period in field. Numbers above diagonal line bars = mean weight increase during experimental period (since Day Zero) in- dicated along X-axis. Numbers above dark bars = mean weight increase for field subgroup during two week period. Sample sizes same as in Fig. 2B. Weights of lab subgroup not shown. weeks. Condition indices of on-site caged clams were compared with those determined for clams collected from natural stream conditions at the original collection site (Table 2). Results Growth of C. fluminea, as determined by in- creases in shell length, and overall weight, over a 40-week period is shown in Fig. 2 B & C. There was virtually no growth in those clams main- tained in Cages #1 and #2 when water tempera- tures were <10°C. Cessation of growth for large clams at <10°C was also recorded for Cages #9 and #10. Noticeable growth was first observed for those clams in Cage #3 when water tempera- tures were ~14°C and rising. Although only negligible growth occurred during the first eight weeks, clams doubled in weight after approxi- mately 15 weeks, but did not double in shell length until the 34th week. Rates of increases in shell length and total weight were calculated at two week intervals to minimize the effect temperature fluctuations have on growth of C. fluminea. On that basis, greatest rate increases in shell length (ranging from 0.48 mm/wk to 0.66 mm/wk) were re- corded for those clams maintained in Cages #4 thru #7 when water temperatures were between 24° and 30°C. Greatest rate increases in weight (ranging from 0.18 gm/wk to 0.26 gm/wk) also occurred in Cages #4 thru #7. "Condition," defined as percentage of total weight made up by soft tissue, of experimental caged clams was comparable to that of natural stream clams (Table 2). Twenty-five of the 300 (8.3%) clams in Cages #1 thru #10 died throughout the course of the study (Fig. 2B). Vol. 99 (4) October 31, 1985 THE NAUTILUS 113 TABLE 1. Collection schedule* for C. fluminea in the Kanawha River, Marmet Dam, W. Va. Cage #1 »2 * 1 14 #5 «i, #7 #8 #9 #10 DAY ZERO 12 Mar 12 Mar 12 Mar 12 Mar 12 Mar 12 Mar 12 Mar 12 Mar 12 Mar 12 Mar 2 weeks 26 Mar 4 'i 8 10 12 14 16 18 20 22 24 .:>■ 28 30 32 u 36 0.8) were used to pro- duce ratios which were used in the Principle ( 'omponents Analyses. All variables were stand- ardized. This was necessary to satisfy the assumptions of the test and also eliminated site specific size related bias. Thus, shell morphology not shell size was the factor tested. Initially all ratms of variables that were linearly related used in the PRINCOMP package in SAS i SAS. 1982). When two ratios with a high degree of correlation to one another (>0.8) were found, one of the pair was omitted from the final analysis following general guidelines for the procedure. The principle components which allowed the greatest differentiation of popula- tions were used to produce plots which showed morphological similarities and differences among populations. Results A preliminary investigation of shell morphol- ogy found some differences in shell morphology among six populations (Hackney and Moorse 1984). Furthermore, these variations were regu- lar enough to be quantified by as few as 10 clams from a population (Hackney and Moorse 1984). Based on the 15 populations examined in this study, three distinctive shell types were visually recognizable (Fig. 2). Broad clams (Fig. 2A) were collected only at Site 9 in Louisiana, a sub- B FIC. '1. Population variation of shell morphology in Polyrto - soda caroliniana. Type A represents Site 9 in Louisiana, type B the normal shell type, type C the highly angular ninrph best represented by the Vankeetown, Florida popula- tion, and type D the typical mixture of slightly angular and typical oval forms found at most sites. Vol. 99(4) October 31, 1985 TIIK NAITIU'S VSA tidal population. Even small elams (<20 mm) showed the broad or elongated shell, character- istic of this population. Clams in this population commonly exceeded 40 mm in maximum length with a few reaching 60 mm. The most common form of P. caroliniana was the oval type (Fig. 2B). This form dominated most sites and was present in all populations except sites 6 and 9. Clams at site 6 had very angular shells (Fig. 2C) and could easily be separated from other popula- tions. Specimens from this population were con- firmed as P. caroliniana (R. T. Abbott, personal communication). The angular characteristic was found in all size classes. Most sites contained clams which included oval as well as some slight- ly angular shells (Fig. 2D). In these collections larger clams tended to be more angular. The only other collection which was visually dif- ferent was one from site 2. This site was dominated by low salinity, low pH water from a blackwater river (Northeast Cape Fear River). Shells were thin and golden in color. Color of the internal shell was also examined. Shells were found which contained purple and/ or golden yellowish coloration. In some shells the typical white color was completely covered by one or more of these colors. Neither the color or extent of coloration was a consistant charac- teristic of any population and was not useful in distinguishing populations from one another. Three populations (Sites 1-3) from different habitats were collected from within the Cape Fear River estuary, NC, and represent a range of salinity from fresh to nearly marine (Table 1). There was some separation of these populations based on Principle Components composed of area/weight and area/width ratios (Fig. 3). There was overlap of the population (Site 1) from the typical P. caroliniana habitat, i.e. Juncus roemerianus marsh, with the salt marsh population (Site 3) and the tidal swamp popula- tion (Site 2). Shells from sites 3 and 2 could be TABLE 1. Physical characteristics of sites and numbers of Polymesoda clams measured. Site Number Number of Clams Measured Pore Water Salinity 0/00 Mean Penetrometer Index Mean % Soil Moisture % Organic Con tent % Sand % Silt % Clay 1 126 8 30 79 52 43 7 49 2 61 0 7 83 58 68 17 15 3 61 26 123 42 8 54 8 38 4 10 2 101 81 26 40 5 55 5 10 0 20 45 5 86 6 8 6 10 6 23 28 75 64 2 34 7 12 5 130 54 10 92 8 0 8 20 5 11 34 5 88 8 4 9 28 3 0 68 9 61 31 7 10 19 * 8 14 42 1 1 39 35 14 11 19 4 20 64 36 24 24 14 12 20 12 21 40 9 42 27 22 13 20 * 15 19 32 6 64 13 17 14 9 20 11 75 21 66 29 5 15 20 15 4 76 24 66 29 5 Salinity determined by silver nitrate titration and conversion of chloride to salinity. Salinity 0/00 = 0.030 + (1.8050 x chlorinity 0/00). 124 THE NAUTILUS October 31, 1985 Vol. 99(4) separated from one another with a high degree of certainty (Fig. 3). Shells from the Spartina tiltentijloru dominated sail marsh (Site 3) were heavy and rounded while those from the tidal swamp (Site 2) were round and light. Genetic differences have been demonstrated for other mollusk species along environmental gradients (Levington 1973; Koehn et al. 1976). When shells from all Atlantic coast popula- tions were examined the same shell characteris- tics (area/weight and area/width) again provided the best resolution via Principle Components Analysis (Fig. 4). Shells from sites 4 and 14 had about the same area/width values as site 3 while sites 7, 8, and 5 were intermediate to sites 1 and 2 (Fig. 4). Site characteristics at sites 14 and 3 were similar in that they were more saline (Table 1), but site 4 was a low salinity site and clams at this site were subtidal. Shells from sites 4 and 14 could be statistically separated from sites 2 and 5 with a high degree (95%) of certainty. Populations from the Gulf of Mexico were best segregated from one another by different princi- ple components, namely weight/maxwidth and height/width ratios. Shells from sites 9 and 11 were easily separated from one another (Fig. 5) and there was only a slight degree of overlap between sites 9 and 10 (Fig. 5). Shells from site 9 (Fig. 2A), as noted previously, were morphol- ogically distinct, as were those from site 6. Shells from sites 6 and 9 exhibited a high degree of overlap (Fig. 5) even though their appearance was different (Figs. 2A and 2C). Most of the remaining Gulf populations exhibited a high degree of similarity (Fig. 5). When all 15 populations were combined one principle component from the Gulf of Mexico analysis and one from the Atlantic coast emerged as the two most important (Fig. 6). Separation of populations previously noted, i.e. sites 9 from 11 and 2 from 3 remain (Fig. 6). Also shells from sites 14 and 4 were distinctly different from sites 11 and 6. Shells from site 9 were again distinctly different from all other populations (Fig. 6). Although separation is possible between some of the populations v\ hen viewed as a whole they form a continuum (Fig. 6). Discussion Populations separated by great distances, or a 3 CAPE FEAR POPULATIONS 1 2 COMPONENT 2 (AREA/WIDTH) FIG. 3. Principle Components plots of the Cape Fear popu- lations. Component 1 was the most important variable in distinguishing between populations while component 2 was second. Site numbers represent means of each population for each component. Elipses represent 95% of all members of the population. Scale on the X and Y axis are irrelevant. ATLANTIC POPULATIONS COMPONENT 2 (AREA/WIDTH) FIG. 4. Principle components plot of all Atlantic coast populations. Means of sites are represented by their respec- tive numbers. Elipses drawn around each mean represent 95% of all members of each population. Populations without elipses contain the same 95% limits as those represented by populations 1, 2 and 3. COMPONENT 2 (HEIGHT/WIDTH) FIG. 5. Principle components plot of all Gulf populations. Site numbers represent means for each. Elipses drawn around means of populations from sites 9, 10, and 1 1 repre- sent 95% of the population. Other populations contain the same size elipses. Vol. 99(4) October 31, 1985 THE NAUTILUS 125 i i- Q < cr < z o a. 5 o o COMPONENT (WEIGHT/MAXWIDTH) FIG. 6. Principle components plot of all populations. Site numbers represent the means of each. Elipses drawn around means represent 95% of all clams in each population. Elipses are not drawn around all populations but are the same size for each. barrier such as the peninsula of Florida, might be expected to have begun the process of genetic differentiation. Polymesoda populations do not show such differentiation, at least as reflected in shell morphology. With the exception of popula- tion 9 (Louisiana) there was almost total overlap between the Atlantic and Gulf populations (Fig. 6). Variations in shell morphology have been shown to exist in Littorina saxatilis and were correlated with genetic differences related to environmental pressures (Janson and Ward 1984). Differences may occur between mollusk populations separated by only one meter if en- vironmental pressures are different, such as in a surf zone (Janson and Ward 1984). Most of the populations examined in this study were from similar habitats, i.e. irregularly flooded Juncus marshes with thick root mats in acidic soil. Such rigorous environments are likely to exert strong selection pressures on filter feeding bivalves and genetic differences are masked by the need of populations to conform critical features such as shell shape and structure. This is character convergence at the species level. The three populations from the Cape Feat- River show a clinal trend from high to low salin- ity (Fig. 3). Shell morphology has been shown to change with distance up an estuary in the case of L. saxatilis (Newkirk and Doyle 1975). Such a trend suggests salinity as a factor related to shell shape, but the trend does not continue if all populations are examined (Fig. 6 and Table 1). Measuring salinity one time during collection of clams may not be enough to correctly describe a habitat. Populations which were readily discernible either through principle components analysis or visual means were from atypical habitats. Popu- lation 9 was from a soft substrate in a subtidal pond. Population 6 contained very angular clams and was also from a soft substrate and well-flooded habitat. Population 2 was in a tidal swamp where the pH of the water is very low for long periods of time due to the influence of a nearby blackwater river. A variety of environ- mental factors can affect shell growth and development in bivalves (Tevesz and Carter 1980; Burky 1983) including temperature, pH, dissolved ions in the water, hydrography, and substrate. Morphological differences between populations may not be detected through elec- trophoretic studies (Janson and Ward 1984) because they may not be the result of genetic differences between populations or the wrong allozymes were selected for study. Although P. caroliniana populations have been identified which can be distinguished from others, through visual as well as statistical means, the important characters for identifica- tion are the narrow, external ligament, the three subequal cardinal teeth, the one anterior lateral tooth and the one posterior lateral tooth 126 THE NAUTILUS October 31, 1985 Vol. 99 (4) which does not extend to the posterior adductor scar (Heard 1982). Acknowledgments I thank Mark LaSalle and Sam Faulkner for collecting specimens from Mississippi and for analyzing those sediments. T. Dale Bishop and Olga J. Pendleton read an early draft of the manuscript and made many helpful comments. Rosemarie Ganucheau kindly drew Figure 2. LITERATURE CITED Abbott, R. T. 1974. Amr run a Scashells. Second edition. Van Nostrand/Reinhold Co., New York. 663 pp. Buoyoucos, G. J. 1927. The hydrometer as a new and rapid method for determining the colloidal content of soils. Soil Science 23:319-330. 1928. Making mechanical analyses of soils in fifteen minutes. Soil Science 25:473-480. Burky, A. J. 1983. Physiological ecology of freshwater bivalves, pp. 281-327 in V. 6 The Mollusca, W. D. Russell- Hunter, ed. Academic Press, NY. Deaton, L. E. 1981. Ion regulation in freshwater and brackish water bivalve mollusks. Physiological Zoology 54:109-121. 1982. Tissue (Na+ Reactivated adenosine- triphosphatase activities in freshwater and brackish water bivalve molluscs. Marine Biology Letters 3:107-112. Duobinis-Gray, E. M. and C. T. Hackney. 1982. Seasonal and spatial distribution of the Carolina Marsh Clam, Poly- mesoda caroliniana (Bosc). in a Mississippi tidal marsh. Estuaries 5:102-109. Gainey, L. F., Jr. 1978a. The response of the Corbiculidae (Mollusca: Bivalvia) to osmotic stress: the cellular re- sponse. Physiological Zoology 51:79-91. 1978b. The response of the Corbiculidae (Mollus- ca: Bivalvia) to osmotic stress: the organismal response. Physiological Zoology 51:68-78. Hackney, C. T. 1983. A note on the reproductive season of the Carolina Marsh Clam, Polymesoda caroliniana (Bosc), in an irregularly-flooded Mississippi marsh. Gulf Research Reports 7:281-284. Hackney, C. T. and C. S. Moorse. 1984. Variations of shell morphologj in the Carolina Marsh Clam, Polymesoda caroliniana, related to environmental factors. Associa- tion of Southeastern Biologists Bulletin 31:60. Heard, R. W. 1982. Guide to common tidal marsh inverte- brates of the northeast Gulf of Mexico. Mississippi- Alabama Sea Grant Consortium, MASGC-79-004, 82 p. Janson, K. and P. Sundberg. 1983. Multivariate morpho- metric analysis of two varieties of Littorina saxatilis from the Swedish west coast. Marine Biology 74:49-53. Janson, K. and R. D. Ward. 1984. Microgeographic variation in allozyme and shell characters in Littorina saxatilis Olivi (Prosobranchia: Littorinidae). Biological Journal of the Linnean Society 22:289-307. Koehn, R. K., R. Milkman and J. B. Milton. 1976. Population genetics of marine pelecypods. IV. Selection, migration, and genetic differentiation of the blue mussel, Mytilus edulis. Evolution 30:2-32. Levington, J. 1973. Genetic variation in a gradient of en- vironmental variability: Marine Bivalvia (Mollusca). Science 180:75-76. Morris, P. A. 1973. A field guide to shells of the Atlantic coast and the West Indies. Houghton Mifflin Co., Boston, MA, 330 p. Newkirk, G. F. and R. W. Doyle. 1975. Genetic analysis of shell shape variation in Littorina saxatilis. Marine Biology 30:227-237. Olsen, L. A. 1976. Reproductive cycles of Polymesoda caro- liniana (Bosc) and Rangia cuneata (Gray) with aspects of desiccation in the adults and fertilization and early larval stages in P. caroliniana. Ph.D. Dissertation. Florida State University, Tallahassee, FL, 117 p. Pamatmat, M. M. 1979. Anaerobic heat production of bi- valves (Polymesoda caroliniana and Modiolus demissus) in relation to temperature, body size, and duration of anoxia. Marine Biology 53:223-229. SAS Institute Inc. 1982. SAS Users Guide: Statistics. SAS Institute Inc., Cary, NC, 584 pp. Subrahmanyam, C. B., W. L. Kruczynski and S. H. Drake. 1976. Studies on the animal communities in two north Florida marshes. Part II. Macroinvertebrate communities. Bulletin of Marine Science 26:172-195. Swingle, H. A, and D. G. Bland. 1974. Distribution of the estuarine clam Rangia cuneata Gray in coastal waters of Alabama. Alabama Marine Resea7-ch Bulletin 10:9-16. Tavesz, M. J. and J. G. Carter. 1980. Environmental rela- tionships of shell form and structure of unionacean bivalves, pp. 295-322 in Skeletal Growth of Aquatic i )rgtmi> m. . I > ( '. Rhoads and R \ 1 ,utz, eds Plenum Press, N. Y. van der Schalie, H. 1933. Notes on the brackish water bivalve Polymesoda caroliniana (Bosc). Occasional Papers of the Museum of Zoology. University of Michigan 258:1-9. Vol. 99(4) October 31, 1985 THE NAUTILUS 127 /* J GROWTH AND OPTIMUM SEEDING TIME FOR THE HARD CLAM, MERCENARIA MERCENARIA (L.), IN COASTAL GEORGIA Randal L. Walker Marine Extension Service University of Georgia P.O. Box 13687 Savannah, GA 31416-0687 ABSTRACT Instantaneous growth rates of the hard clam, or Quahog, Mercenaria mercenaria (L.), in Georgia were studied to determine the best time to seed clams to obtain maximum growth. Clam growth occurs in two distinct phases. During the first phase, juveniles grow continuously throughout the year with most rapid g?'owth in the spring and declining growth through the summer, fall and winter. In phase two, the growth of clams approximately 1 V2 years old oscillates with decreasing amphitude over time. Because, in Georgia, juvenile clams grow most rapidly during the spring that time or late winter is considered the best for seeding to obtain maximum yields. Introduction The coastal waters of Georgia support approx- imately 450,000 acres of salt marsh or ap- proximately 33% of the salt marshes along the Atlantic seaboard. During the early part of the century, these marshes supported a large oyster and small clam fishery. Today, the oyster in- dustry is almost non-existent (Harris, 1980), and clamming is sporadic (Walker et al., 1980; Walker, 1984a). This is unfortunate because most of the coastal waters of Georgia are rela- tively free of pollution and are suitable for the commercial culturing of shellfish. As more northern waters are closed to shell- fishing due to pollution (National Marine Fishery Service, 1977), the opportunity to use the coastal waters of Georgia for shellfish culture increases. Hard clams, or the Northern Quahog, Mercenaria mercenaria (Linnaeus, 1758), grow rapidly throughout the year in southern waters (Menzel, 1963; Eldridge et al, 1976; Walker, 1984b). In South Carolina, clam growth occurs throughout the year but varies seasonally (Eldridge et al.. 1976). In Florida, growth is most rapid in fall and spring, slower in winter and slowest in summer (Menzel, 1963; 1964). In contrast, growth in northern waters ceases during winter when water temperature cool to 5 to 6°C (Loosanoff, 1939). Most rapid growth is in the summer when water tempera- tures reach 20°C (Ansell, 1968). The culture of hard clams may be one means of increasing shellfish production in Georgia. Clams planted at 6-mm in shell length at a den- sity of 509/m2 within predator exclusion cages grow to commercial size (44.4-mm in shell length) within 17 months with good survival rates (Walker, 1984b). However, to assure high survival rates, crab larvae which entered cages had to be removed monthly, until clams reached a shell length of approximately 20-mm. At larger sizes, they were immune to predation by small crabs. By determining the optimum time for seeding clams, it may be possible to decrease the time re- quired to obtain a marketable product. Eldridge et al. (1979) observed that clams in South Carolina grew best in spring and fall and recom- mended seeding in the fall. Earlier Eldridge et al. (1976) reported that clam grew best in spring and summer. These conflicting reports suggest that fall may not be the best planting time for clams in southern waters. The purpose of the research reported here was to determine the optimum seeding time for obtaining maximum growth of hard clams in the coastal waters of Georgia. Materials and Methods The growth of three stocks of hard clams from 128 THE NAI'TIU'S October 31, 1985 Vol. 99 (4) Georgia, Massachusetts and Virginia stocks were compared. Local clams, collected from iicar Cabbage Island, Savannah, Georgia, were shipped to Virginia Institute of Marine Science (VIMS), Eastern Shore Laboratory, Wacha- preague, Virginia, where they were spawned. Their offspring were returned to Georgia when they had grown to a shell length of 10.4 ± 1.2 (SD) mm. VIMS also supplied a fast growing stock of Virginia clams with a mean shell length of 11.0 ± 1.2 (SD) mm. A third stock (12.8 ± 1.8 mm), also selectively bred for rapid growth, was obtained from Martha's Vinyard Shellfish Group, Oak Bluffs, Massachusetts. The clams were planted on November 30, 1980 near Cabbage Island (Fig. 1) in 1 x 1 x 0.3 m cages constructed of 6-mm vexar plastic. Three replicate cages per stock were seeded at a densi- ty of 1000 clams/m2. The cages were buried in a sandy substrate to a depth of 0.15 m and the enclosed bottom was layered with 5 cm of gravel aggregate in an attempl to minimize crab preda tion (Castagna and Kraeuter, 1977). The corners of the cages were attached to 1 m stakes. All cages were sampled seasonally over two years by sieving all of the sediment through a 5-rnm screen. The clams were counted and their shell length measured (the longest possible measurement, i.e., anterior-posterior) to the nearest 0.1-mm with vernier calipers. Sediment and clams were then returned to their respec- tive plots. Two cages (1 x 1 x 0.5 m) constructed of 3-mm-mesh vexar plastic attached to a frame of 13-mm steel reinforcement rods were divided into nine compartments of 0.11 m2 each. Cages were buried to a depth of 0.25 m on an intertidal sandflat near Cabbage Island, Georgia in May 1982 (Fig. 1). In June 1982, 6-mm seed clams supplied by Aquaculture Research Corporation were planted and maintained at the following replicate densities: 56, 111, 222 and 333 clams/0. 11m2 or the equivalent to 509, 1009, 2018 and 3027 clams/m2, respectively. The center compartment of the cage was seeded with approximately 500 clams to replace those that died. In the other cage, clams with an average shell length of 39 mm, were planted at the following densities: 10, 25 and 45 clams/ il', 1. Map of Wassaw Sound, Georgia showing experimental growing site at Cabbage Island. Vol. 99 (4) October 31, 1985 THE NAUTILUS 129 0.11m2 or the equivalent to 91, 227 and 409 clams/m2. Cage I (6-mm clams) was sampled monthly while Cage II was sampled seasonally. In each case clams, crabs and sediment to a depth of 0.25 m were sieved through a 5-mm screen. Clams were counted, the shell length of a sub- sample (N = 70) measured and clams were added if needed to keep the density constant in each compartment. Crabs were identified to species, measured for carapace width and discarded. After January 1983, Cage I was sampled sea- sonally because survival had remained at ap- proximately 100% for several months (Walker, 1984b). Clams (N= 174) from field populations located near Cabbage Island were used to determine the relationship between shell length and ash-free dry weight (AFDW). After they were measured to the nearest mm, the flesh was removed and dried to constant dry weight at 80 °C for 48 hours. Ash weight was determined by combust- ing the sample at 475°C for 16 hours and ash- free dry weight determined by difference. The resulting equation is: g AFDW = 0.00000726 (shell length in mm) 2.98, r2 = 0.99. The instantaneous growth value G equals the instantaneous increase in meat weight over given time intervals (seasons in this case). G is calculated as Ln(Wt/Wo) where o and t repre- sent the beginning and end of each time inter- val. The ash-free dry weight value (W) was determined by taking the mean shell length at each sampling and inserting that value into the above shell length to mean individual meat ash- free dry weight regression equation. An exam- ple is given in Table 1 . Results Instantaneous growth values (G) for the three clam stocks are given in Table 2 and values ob- tained at different clam densities per age class are given in Table 3. Older clams grew well in fall and spring, with moderate growth in sum- mer and poor growth in winter. The growth of the 0 to 1 year old clams did not show the characteristic reductions in growth during the summer; however, the reduced growth in winter is apparent. This phenomenon is observed both in the stock seed clams' first summer (Table 2; Summer 1981) and in the seed clam density ex- periment (Table 3; Summer of 1982 and 1983). However it is not observed among older clams or in the second year of the stock experiment. Clam growth in Georgia appears to go through two phases (Fig. 2). During the first phase, clams 0 to approximately IV2 years in age appear to grow in a linear fashion with most rapid growth in the spring and decreasing growth through the following seasons. In the second phase, clam growth oscillates with decreasing amphitude over time. TABLE 1. Growth data for the hard clam. Mercenaria mercenaria, cage planted with yearlings at a density of 91/m2 Mean shell Mean Ind: Lvidual Instantaneous Growth Date length in mm Wgt in g AFDW (G) June 1982 39.9 0.4284 0.15 September 1982 42.0 0.4991 0.32 December 1982 46.7 0.6847 0.07 March 1983 47.7 0.7293 0. 19 June 1983 50.8 0.8799 0.08 September 1983 52.2 0.9514 0. 18 December 1983 55.3 1.1331 0.06 March 1984 56.5 1.2079 0.18 June 1984 60. 1 1.4485 0.10 September 1984 62.2 1.6085 0. 14 December 1984 65.1 1.8425 130 THE NAUTILUS October 31, 1985 Vol. 99 (4) Discussion The two phase growth pattern for hard clams in southeastern Atlantic coast waters can be ex- plained in terms of poor growth conditions in winter and the reproductive cycle of clams. Clams in Georgia and South Carolina exhibit a distinct bimodal reproductive cycle (Pline, 1984; Eversole et al., 1980) with spawning occurring from spring well into fall. The peak spawning periods of Georgia clam populations is in May and October (Pline, 1984), while in South Carolina peaks are in May to June and in September to October (Eversole et al., 1980). According to Belding (1931), clams in Massachusetts reach sexual maturity at shell lengths of 32 to 38 mm. Thus maturity is related to size rather than age. In South Carolina populations, a small percent of males and females spawned at an approximate average shell length of 18 to 22 mm (Eversole et al., 1980; Fig. 2; Eldridge et al, 1979; Table 4); however, most clams did not spawn until they reached an average size of 28 to 32 mm. Thus, until clams are approximately 1 to IV2 years old, energy is used for growth rather than reproduc- tion resulting in the seasonally linear decline clam growth between spring and winter. When sexual maturity is reached, clam growth in sum- mer is reduced because some clams continue to spawn while others regenerate biomass lost dur- ing spring spawning. The result is cyclic growth. The results of this work are comparable to other studies of hard clam growth in south- eastern United States. In this area, clams grow year around with most rapid growth in spring and fall (Eldridge et al, 1976, 1979; MenzeL 1963). Mercenaria mercenaria seed clams, ob- tained from a Connecticut hatchery, and grown in coastal Florida grew well in spring and fall with slow growth in winter and least growth in summer. However, with naturally occurring sets of Mercenaria campechiensis Gmelin seed clams growth was best in spring and fall, rapid in summer and slowest in winter (Menzel, 1963). In Georgia, Mercenaria mercenaria grew best in spring and fall with little growth in winter TABLE 2. Instantaneous growth values per season per hard clam, Mircc/iurm mercenaria, stuck from fall 1980 to fall 1982. Data is from Walker (1984a). STOCK Fall 80 Win 81 Spr 81 Sum 81 Fall 81 Win 82 Spr 82 Sum 82 Fall 82 Georgia 0.26 0.91 1.10 .0.75 0.44 Massachusetts 0.05 0.47 0.80 0.55 - Virginia 0.A8 1.02 1.27 0.85 0.34 0.25 0.38 0.28 0.25 0.21 0.2C 0.33 0.19 TABLE '.i. Instantaneous growth values ((!) per season per hard clam, Mercenaria mercenaria, density per age class from summer 1982 to fall 1984. Instantaneous growth values for the seed clams arc from data reported in Walker (1984b) and those for the one year old clams (yearlings) are from unpublished data. DENSITY Sum 82 Fall 82 Win 83 Spr 83 Sum 83 Fall 83 Win 84 Spr 84 Sum 84 Fall 84 Seed Clams 509/m2 2.15 1.75 0.48 0.82 0.68 0.34 0.05 0.33 0.18 1009/m2 2.38 1.64 0.40 0.74 0.56 0.20 0.04 0.18 0.03 2018/m2 2.13 1.74 0.40 0.72 0.23 0.10 0.08 0.15 0.02 3027/m2 2.18 1.62 0.39 0.67 0.01 0.18 0.05 0.00 0.03 YEARLINGS 91/m2 0.15 0.32 0.07 0.19 0.08 0.18 0.06 0.18 0.11 0. 14 227/m2 0.17 0.31 0. 16 0.19 0.11 0.19 0.05 0.16 0.10 0.09 409/m2 0.21 0.27 0.12 0. 18 0.13 0.20 0.03 0.14 0.10 0.06 Vol. 99(4) October 31, 1985 THE NAUTILUS 131 1 10 1.00 090 080 a c 0 70 J o O 060 w I s 2 040 to C 0 30 0 20 - 0 10 - — G values for Seed Clams planted at 509/ m2 G values for the Georgia Stock Clams — G values for the yearling clams planted at 91 m2 Spr Sum Fall Win Spr Sum Fall Win Spr Sum Fall Win Spr Sum Fall Win Time in Seasons FIG. 2. Growth of hard clams, Mercenaria mercenaria, grown in predator exclusion cages on Cabbage Island, Wassaw Sound, Georgia. (Godwin, 1968) while no clam growth data was obtained from the summer period, growth in August was approximately 10% of the total ob- tained during the experiment. Mercenaria mercenaria seed clams from a North Carolina hatchery which were planted in coastal South Carolina grew best in spring and fall, with least growth in winter (Eldridge et al., 1979). In an earlier study, clam growth was reported best in spring and summer (Eldridge et al., 1976). These conflicting reports of clam growth pat- terns in South Carolina can be explained if one recognizes that there are two seperate phases of clam growth. For the first study (Eldridge et al., 1976), clam growth was determined over 15 months compared to 33 months in the later study (Eldridge et al., 1979). Assuming that the ash-free dry weight to shell length regression equation can be applied to those in South Carolina, the instantaneous growth values for the two South Carolina clam studies, based on shell lengths reported, are given in Table 4 and 5. This data shows that the growth patterns of South Carolina clams are similar to those in Georgia (Table 3; Fig. 2) over comparable time periods. In Eldridge et al. (1979), growth with time (33 months) shows that clam growth is best in fall and spring; however, if one examines only the first 15 months of the study, one would con- clude that clams grew best in summer and fall. Data presented in this report and that above suggest that optimum clam growth in Georgia and South Carolina depends upon age of the clam and planting time. From set to approx- imately IV2 years of age, clams grow well in spring, summer and fall depending upon seeding time, but do not grow well in winter. Older clams grow well in spring and fall, moderately in summer and poorly in winter. Planting time may be an important factor in clam growth and in survival. Eldridge et al. (1979) recommended seeding South Carolina seeding areas at 300 clams/m2 in fall. Based on the results of my studies which show that clam 132 THE NAUTILUS October 31, 1985 Vol. 99 (4) TABLE 4. Instantaneous growth values (G) per season as calculated from clam growth data for clams planted at 290/m2 in Clark Sound, South Carolina as reported in Table 3 of Eldridge et al (1976). Mean She 11 Mean Individual Instantaneous Growth Dace 1 engl h in on Wgt in g AFDW (G) March 1974 17.29 0.0354 1.07 June 1974 24.78 0.1036 0.90 September 1974 33.51 0.2547 0.41 December 1974 38.47 0.3842 0.25 March 1975 41.81 0.4924 0.31 June 1975 46.34 0.6691 TABLE 5. Instantaneous growth values (G) per season as calculated from clam growth data for clams planted intertidally at 290/m! in Clark Sound, South Carolina as reported in Table 4 of Eldridge et al. (1979). Mean Shell Mean Individual Instantaneous Growth Date length in mm Wgt In gAFDV (G) June 1975 13.86 0.0183 0.88 September 1975 18.62 0.0442 0.92 December 1975 25.33 0.1106 0.63 March 1976 31.25 0.2068 0.64 June 1976 38.77 0.3932 0.18 September 1976 41.12 0.4686 0.22 December 1976 44.34 0.5867 0.12 March 197 7 46.15 0.6609 0.33 June 1977 51.56 0.9197 0.08 September 1977 52.91 0.9933 0.03 December 1977 53.36 1.0187 0.08 March 1978 54.77 1.1010 growth during the 0 to IV2 year stage does not decline appreciably during the summer, I recom- mend seeding in late winter or early spring. If planted in early spring, clams will pass through three seasons of good growth before reducing growth in the winter. Furthermore, if planted in early spring or late winter, clams may grow to a sufficient size to prevent their predation by new- ly metamorphosed crabs which enter the cages. Blue crab, Callinectes sapidus Rathbun, spawn- ing occurs between early May and October in Chesapeake Bay (Van Engle, 1958), from March to September in Georgia (Palmer, 1974) and from February to October in Florida (Tagatz, 1968). The peak spawning of blue crabs is from June to October. Mud crabs, Panopeus herbstii (Milne-Edwards), spawn from late spring through summer in South Carolina with great- est numbers of newly metamorphosed crabs oc- curring in July and August (Dame and Vern- Vol. 99(4) October 31, 1985 THE NAUTILUS 133 burg, 1982) and from February to October in Florida with peak spawning in June and October (Tagatz, 1968). Thus, clams planted in late winter or early spring may grow to a size suffi- cient to prevent predation by newly metamor- phosed crabs before the peak spawning season of crabs is reached. Acknowledgments The author wishes to thank Dr. D. Menzel for reviewing the manuscript. Special thanks are given to Ms. A. Boyette and S. Mcintosh for the graphics. The work was supported by the Georgia Sea Grant Program, under Grant No. USDL-RF/8310-21-RR100-102. LITERATURE CITED Ansell, A. D. 1968. The rate of growth of the hard clam, Mercenaria mercenaria (L.), throughout the geographical range. J. Cons. Perm. int. Explor. Mer. 31:364-409. Belding, D. L. 1931. The quahog fishery of Massachusetts. The Commonwealth of Massachusetts, Marine Fishery Series No. 2, 41 pp. Castagna, M. A. and J. N. Kraeuter. 1977. Mercenaria cul- ture using stone aggregate for predator protection. Proc. Natl. Shellfish. Assoc. 67:1-6. Dame, R. F. and F. J. Vernburg. 1982. Energetics of a popu- lation of mud crabs, Panopeus herbstii (Milne-Edwards), in the North Inlet Estuary, South Carolina. Journ. Exp. Mar. Biol. Ecol. 63:183-193. Eldridge, P. J., W. Waltz, R. C. Gracy and H. H. Hunt. 1976. Growth and mortality rates of hatchery seed clams, Merce- nann itu m nana, in protected traj - in waters of South Carolina. Proc. Natl. Shellfish. Assoc. 66:13-20. Eldridge, P. J.. A. G. Eversole and J. M. Whetstone. 1979. Comparative survival and growth rates of hard clams, Mercenaria mercenaria. planted in trays subtidally and intertidally at varying densities in a South Carolina estuary. Proc. Natl. Shellfish. Assoc. 69:30-39. Eversole, A. G.. W. K. Michener and P. J. Eldridge. 1980. Reproductive cycle of Mercenaria mercenaria in a South Carolina Estuary. Proc. Natl. Shellfish. Assoc. 70:22-30. Godwin, W. F. 1968. The growth and survival of planted clams, Mercenaria mercenaria, on the Georgia coast. Georgia Game and Fish Commission Contribution Series No. 9, 16 pp. Harris, D. C. 1980. Survey of the intertidal and subtidal oyster resources of the Georgia coast. Georgia Dept. Natl. Resources, Coastal Resources Div.. Brunswick, Georgia. 44 pp. Loosanoff, V. L. 1939. Effects of temperature on shell movements of clams, Venus mercenaria (L.). Biol. Bull. 76:171-182. Menzel, R. W. 1963. Seasonal growth of northern quahog, Mercenaria mercenaria, and the southern quahog, Mercenaria campechiensis, in Alligator Harbor, Florida. Proc. Natl. Shellfish. Assoc. 52:37-46. Menzel, R. W. 1964. Seasonal growth of northern and south- ern quahogs, Mercenaria mercenaria and M. campechien- sis, and their hybrids in Florida. Proc. Natl. Shellfish. Assoc, 53:111-119. National Marine Fishery Service, 1977. The mollusean shell- fish industries and water quality: Problems and oppor- tunities. U. S. Dept. of Commerce, NOAA, Natl. Mar. Fish. Serv., Off. Fish. Devel., Supt. Docs., Washington. D.C. v + 46 pp. Palmer, B. A., 1974. Studies on the blue crab (Callinectes sapidus) in Georgia. Georgia Dept. Nat. Resources, Brunswick, Georgia. Contribution Series No. 29, 59 pp. Pline, M. J. 1984. Reproductive cycle and low salinity stress in adult Mercenaria mercenaria (L.) of Wassaw Sound, Georgia. Masters Thesis, School of Applied Biology. Georgia Institute of Technology, Atlanta, Georgia. 74 pp. Tagatz, M. D. 1968. Biology of the blue crab, Callinectes sapidus Rathburn, in the St. Johns River, Florida. Fish. Bull, 67:17-33. Van Engle, W. A. 1958. The blue crab and its fishery in Chesapeake Bay. Part I: Reproduction, early develop- ment, growth and migration. Comm. Fish. Review 20:6-17. Walker, R. L. 1984a. Population dynamics of the hard clam, Mercenaria mercenaria (Linne) and its relation to the Georgia hard clam fishery. Masters Thesis, School of Applied Biology. Georgia Institute of Technology, Atlanta, Georgia. 121 pp. 1984b. Effects of density and sampling time on growth of the hard clam, Mercenaria mercenaria, planted in predator-free cages in coastal Georgia. The Nautilus 98:114-119. Walker, R. L., M. A. Fleetwood and K. R. Tenore. 1980. The distribution of the hard clam, Mercenaria mercenaria (Linne), and clam predators in Wassaw Sound, Georgia. Georgia Marine Science Center. Tech. Rept. 80-8. 59 pp. 134 THE NAUTILUS October 31, 1985 Vol. 99(4) ANATOMY OF OXYLOMA NUTTALLIANA CHASMODES PILSBRY Dorothea S. Franzen Illinois Wesleyan University Bloomington, IL 61701 ABSTRACT Shell characteristics, anatomical features of reproductive organs, radula and jaw, pigmentation of body and habitat of the -pulmonale, succineid gastropod, Oxyloma nuttalliana chasmodes are described from the University of Washington campus, Seattle, King County, Washington. H. A. Pilsbry (1948) described Oxyloma nut- talliana subspecies chasmodes from its shell. He reported the subspecies from only the type locality, Stockton, California. In early August, 1983, 1 collected from the bases of short grasses, on the wet ground of the unshaded shore of Union Bay, at the edge of the campus of the Uni- versity of Washington, Seattle, King County, Washington, a succineid gastropod which I have identified as 0. nuttalliana chasmodes Pilsbry after comparing the shell with characters as described and figured by Pilsbry (Pilsbry, 1948, pp. 795-796, Fig. 426) and with the holotype (our Fig. 1, E, F) and paratypes (our Fig. 1, C, D) from the collection of the Academy of Natural Sciences of Philadelphia, no's. 5609 and 5609a. Anatomical features, pigmentation of the body, as well as shell characters need to be employed in the identification of succineid gastropods. I am describing shell, body features and anatomy of the above identified subspecies assuming the anatomy is similar to those of the snails of the shells described by Pilsbry. Shell: Amber-colored, translucent, very fragile, imperforate, broadly ovate, composed of up to three whorls separated by a sharply in- cised suture (Fig. 1, A, B). Range in height of eight shells of this series is 13.3 mm to 8.2 mm; range in width 7.0 mm to 4.7 mm. Dimensions and ratios of dimensions of shells are recorded in Table 1. A knoblike nuclear whorl tops the short spire; whorls increase rapidly in size resulting in an elongate ultimate whorl. Nuclear whorl finely wrinkled, punctate (Fig. 2). Irregularly-spaced longitudinal striations fine on lower part of nuclear whorl increase grad- ually, becoming coarser on ultimate whorl. Aperture broadly ovate, occupies about 80% to 85% of entire height of shell. Peristome sharply edged; thin callus on ultimate whorl above the aperture; whitish columella follows inner border of peristome, curves as it disappears into the ultimate whorl. Dimensions of the holotype and paratypes also are recorded in Table 1. The height attained by shells of that series is 16.7 mm. The difference in height of the two series may be attributable to a difference in time of summer when collected. The larger, more mature snails may not survive later than sometime in July, therefore, those from the Seattle site, collected in August, prob- ably do not represent maximum size for the species. Body and Mantle Surfaces: (Fig. 3). Body wall cream-white, transparent, irregularly tubercu- late. Some individuals sparsely, others more darkly, pigmented. Pigmentation of dorsal body surface consists of fine (small) black flecks ex- tending from anterior end of head to junction of mantle and body wall. Mid-dorsally on the head black flecks of indistinct bands form an ill- defined triangle, narrowing to a band between the superior (posterior) tentacles, dividing and continuing as a double band mid-dorsally the length of the body. On either side two bands parallel the double median band. Surface of superior tentacles flecked. Pigmentation of lateral body wall consists of spots of fine (small) flecks forming an indistinctly outlined band. Genital aperture, approximately 1.0 mm in length, surrounded by a white, tumid lip, is situated on anterior right-hand side of body. On either side a pedal groove, continuous from labial palp to posterior tip of body, separates foot from lateral body wall; pedal groove paral- leled by a less pronounced suprapedal groove. Vol. 99 (4) October 31, 1985 THE NAUTILUS 135 B FIG. 1. Shells of Oxyloma nuttalliana chasmodes Pilsbry: A, B, Locality, Seattle, Washington, (Height, 11.4 mm); C, D, Paratype (Height, 12.8 mm); E, F, Holotype (Height, 16.5 mm). k FIG. 2. Scanning-electron-photomicrograph of nuclear whorl of Oxyloma nuttalliana chasmodes Pilsbry. •*& FIG. 3. Pigmentation patterns of head, body and mantle of Oxyloma nuttalliana chasmodes Pilsbry. Shallow, vertical grooves incise the suprapedal and pedal grooves and body wall producing shallow scallops along margin of body wall especially when animal is in a somewhat con- tracted state. Sole of foot cream-white, un- pigmented. Mantle collar flecked with black pigment. Along anterior margin of mantle are patches of black pigment from which streaks extend poste- riorly becoming diffuse over the mantle surface. In mature snails these streaks are concentrated between pulmonary blood vessels. The main pul- monary vessel is variably outlined by the pig- ment (Fig. 3). Flecks are scattered over the light yellow nephridium. An elongate black blob on the left anterior nephridial margin is followed by 136 THE NAUTILUS October 31, 1985 Vol. 99(4) ^ JO ro P a. 3 H- OQ V ro 3 & On ►-- si O-J CrJ O O on ro 00 00 & on On On 00 00 a- 4- n en H -o ~ p o "3 P O i — M i — ' H- o ro P 0 Hi 7T rt c+ n rt >— 3 ^ H O O — = 3 O C H- » (D Ul 3" O si si On KJtsJi-uhohJtsjroNjroN) ^K-l— I— H- t— 'I— t— O-l^- 4^4^-Pkro4^4=*4^-ro4^r>J ^WWCCCOsJHUInIUI 00 00 o -&» •t'Uio^^i^'ocoai'joo OvjsjHNjwHooLno KJ 00 OJ OJ On on oo~io~io~icr>o~iono~io~ic** l— 'OntOOnO^OOO-lOO UUDslOOOOO^^slOi 00 -£» 01 o ONJONJOnonNjO^OOn OOOOOOOOOOOOOOOOOOOO O'-P'OOiO^CO^MOOO 00 00 3 H* 3 01 p yi (-*■ fl> 00 3- rt 3" cr o 1— i M- rt H- 3 3 Q- 3 i- 3 H* / V 00 ro os < CO tt 00 rt rt 0) P Oi O O »-i X 'j' C/l 3 3 (/) - 4^ 3" w H- (t> rt O o -u IsJWWNJMWlyJOJ H H U W H H \ -s "s. "s. \ \ Ji. K) 4> 4^- NJ NJ I— ' r— ' Ol CO COIOOHHMWU ^O 4^ W fJ Mat^JitO^^W s) 4^ O -J vJUlOAODWOsl on on lyi Ln onononOnon4^onOn CT^a^ si O slslO^O^NHOUiO O >— ' 0-4O-J UMO^HHMHOJ O 00 o o *— • (J- On CT^ OslOOOOOOOO K) CO OOOOOn-^JOKJl— ' 00 s] OOCOOOsIOOOCCCnJ onro oo>— 'roonOf— 00 si CO i.MHOOsJOOO'O ' 00 U3 00 ''I w ^ o Oo o^ o &■ COCOCOCOCOCOCOiO OWWU1WOCOM COC-O-J^COOOnO On On On Js. CO CO \D UD i— o t— on UlUlUlUlUlfcWUl ytOOClOC/llDtOOO Oo^gi—H-oocnOO 3" O o • ■d ro M 00 4 rt rt 3" C O (t cn > 3-13 C/l > 3-T3 TO • ■a "a 2 t al 3- (C 3- I? C- ft s. ,^ S' > a ~ _ r 5 H a r P° a Si. -■ o g 3 3 W — O o ~* ~*> 71 r-> 3" 3" 2. ro — rs ; — >-h - ; < •-. — ^ ^ '- = 2 ro 3 3- = o ej, ro ? Sip r » ^ a 2. "" << i TO W hJ ^ r-t O 01 s. » E3 re [B Ei rt 3- 3 ro ^ " cfq' P S^ 3" -I 3 3" r~ - 3 Htl r« 3 - ro — - 1 - rta j. c ro 3 — P a •; a < n o '— . - Vol. 99(4) October 31, 1985 THE NAUTILUS 137 lesser patches or by a narrow, indistinct or a continuous band along the nephridial margin. Other patches of pigment are scattered over the left-hand side of the mantle. Reproductive Organs: (Fig. 4). Albumin gland light cream-colored, triangular, composed of fine acini, enclosed within a thin, transparent, unpigmented sheath. Seminal vesicle elongate, subequally bilobed terminally, enclosed within a thin, transparent sheath speckled with black pigment. The darkly pigmented hermaphroditic duct joins the seminal vesicle to form the fertili- zation sac from which diverge the oviduct and the sperm duct which leads into the prostate gland. Prostate gland light cream-colored, ovate, elongate, enclosed by a thin, transparent, non-pigmented or sparsely flecked sheath, com- posed of acini which are coarser than those of the albumin gland. Vas deferens slightly pep- pered with black pigment. As the vas deferens approaches the penis from the prostate gland it follows the penis along its dorsal surface and enters the penial sheath distally. Within the penial sheath the vas deferens becomes the coiled epiphallus, enters the penis subterminally resulting in a penial appendage. Penial append- age elongate, digitiform and recurved. Penis coiled in a half turn before giving off appendage (Fig. 4, A, B). Penial retractor muscle, a white band, pierces the penial sheath at its distal end to be attached to the epiphallus. Vagina, longer than the penis, straight and non-pigmented. Spermatheca large, inflated. Spermathecal duct transparent, wide, stout as it approaches and enters the vagina terminally. Oviduct highly convoluted, enters the vagina distally, ventral to the spermathecal duct (Fig. 4, C). Radula and Jaw: The radula is composed of many rows of teeth and numerous teeth to a row. The number of rows in four radulae ex- amined ranges from 76-86. The ratios of margi- nals to laterals approaches 1:4 and 1:5 (Table 2) which is within the range of other species of Oxyloma as reported: 0. retusa (Lea) (Franzen, 1963, Table II, p. 89), 0. salleana (Pfeiffer) (Franzen, 1966, Table II, p. 65), 0. haydeni (W. G. Binney) (Franzen, 1964, Table II, p. 78) and 0. deprimida Franzen (Franzen, 1973, Table 2, p. 71). Structural details of individual teeth resemble PA PS p EP P PRM EP PA B PRM SPD HD FIG. 4. Drawings of genital organs of Oxyloma mittatliana chasmodes Pilsbry. A, B, P, penis; PA, penial appendage; EP, epiphallus (shown inside of penis sheath cut open); PRM, penial retractor muscle. C, P, penis; VD, vas deferens; PRM, penial retractor muscle; SPD, spermathecal duct; SP, sper- matheca; HD, hermaphroditic duct; VA, vagina; OD, oviduct; PG, prostate gland; FS, fertilization sac; SV, seminal vesicle; AG, albumin gland. 138 THE NAUTILUS October 31, 1985 Vol. 99 (4) TABLE 2. Formulae of representative rows of teeth of Oryloma nuttalliana chasmodes Pilsbry from four specimens; Field no. DSF 554, Seattle, Washington. si Lde No. of Rows of Teeth Row M L ( : l M 1 80 31 30 - 6 - - 6 - 31 32 31 - 6 - - 6 - 31 2 82 23 24 30 35 - 8 - 9 - - 9 - 34 36 3 SI, 25 28 36 38 - 8 - - 7 - 4 76 27 25 - 5 - - 6 - 25 LJ 1 5-L-M 26-L-M B FIG. 5. A, Representative radula teeth of Oxyloma nuttaU Inn,, i rhaswoilrs Pilsbr\ (', centra! tooth; 1 I.I., 1-1 left lateral; 7-L-L, 7th left lateral; 1-L-M, 1st left marginal; 5-L-M, 5th left marginal; 26-L-M, 26th left marginal. B, A jaw of Oxyloma nuttalliana chasmodes Pilsbry. those of the genus in general (Fig. 5, A). The central tooth has a broad basal plate which has a pointed or bluntly rounded projection on either side. The pointed mesocone, somewhat variable in length, does not extend to the lower margin of the basal plate. A shorter, pointed ectocone Hanks the mesocone on either side. The laterals have a large, pointed mesocone which, also, is not as long as the basal plate. The single ecto- cone, sometimes divided into two -especially of the more lateral teeth -is pointed; a short, pointed endocone may be present. The margi- nals, smaller than the laterals, have a long, slender basal plate which is characteristic of the is Oxyloma (Quick, 1933:296, Fig. 1, Oxyloma (Succinea) pfeifferi "Rossm."). Of the cusps of the marginals the mesocone is the larg- est, the endocone shorter and pointed. The ec- tocone of the two, sometimes only the first and also the third, medial-most marginals is divided into two unequal cusps of which the lateral-most is the larger. Rarely a marginal whose ectocone is divided into three cusps appears between two with the ectocone divided into two cusps. The ectocone of the more lateral marginals is divided into three and as many as six cusps of which the outermost is curved and the largest. The features of the amber-colored jaw are typical of the genus (Fig. 5 B). A prominent median fold projects anteriorly and is flanked on either side by a broadly rounded fold. Poste- riorly the margin of the collar has a fold on either side of a median indentation. I have not sufficiently examined shells and soft anatomy of succineas identified as Oxyloma nuttalliana (Lea) to determine whether or no1 0. nuttalliana chasmodes Pilsbry should be a subspecies or a valid species. Further studies, including geographic distribution and habitats, are needed to make such a determination. Acknowledgments National Science Foundation Grants-in-Aid No's. NSF GI8000 and NSF GB2715 provided laboratory equipment. Scanning-electron photo- micrographs were the courtesy of Dr. M. J. Nadakavukaren, Illinois State University, Normal Illinois, Dr. George M. Davis, Academy of Natural Sciences of Philadelphia, Philadel- phia, Pennsylvania, lent shells of the museum collection. Dr. A. Byron Leonard, University of Kansas, Lawrence, Kansas, read the manu- script and offered helpful suggestions. LITERATURE CITED Franzen, Dorothea S. 1963. Variations in the Anatomy of the Succineid Gastropod Oxyloma retusa. The Nautilus 76(3):82-95, tables 1-2, figs. 1-4. 1964. Anatomy of the Succineid Gastropod Oxyloma haydeni. The Nautilus 77(3):73-81, tables 1-2. fig. 1. 1966. Anatomy of the Succineid Gastropod Oxyloma sallvana (Pfeiffer). 1'h, Nautilus 80(2):59-69, tables 1-2, figs. 1-3. 1973. Oxyloma licprimiiUi. A New Species of Succineidae(Pulmonata). The Nautilus %7@):66-71, tables 1-3, figs. 1-4. Vol. 99 (4) October 31, 1985 THE NAUTILUS 139 Pilsbry, Henry A. 1948. Land MoUusca of North America (North of Mexico). Acad. Nat. Sci. Philadelphia Monograph No. 3, vol. 2, pt. 2: pp. i-xlvii + 521-1113. 585 figs. Quick. H. E. 1933. The Anatomy of British Succineae. Proc. Mala. Sac. London 20(6, Nov.):295-318, pi. 23-25, figs. 1-18, Tables I-V. PSEUDOTORINIA BULLISI, NEW SPECIES (GASTROPODA: ARCHITECTONICIDAE) FROM SUBTROPICAL WESTERN ATLANTIC Riidiger Bieler Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, D.C. 20560 The species we describe herein was first men- tioned by Merrill (1970), in his unpublished study of the Atlantic Architectonicidae. The senior author is completing a study of the Indo-Pacific species of Architectonicidae and needs an avail- able description of this species for purposes of comparison with some closely related species of the Indo-Pacific. We place the species in the genus Pseudotorinia Sacco, 1892, based on the revision by Bieler (1985). Terminology of shell sculpture follows Bayer (1940:224) and Bieler (1984:455). Pseudotorinia bullisi, new species Fig. 1 Description: Shell small, solid, with a max- imum diameter of 10.2 mm and height 3.6 mm, upper surface flattened, with only a weakly channeled suture; base slightly convex and obliquely angled to about halfway, then flat- tened on to the umbilicus. Color whitish, ir- regularly mottled with light-brown, or uniform light-cream. Whorls up to 4Vs, strongly angu- lated, tightly coiled and joined at the midline of the prominent peripheral cord. Protoconch small, smooth, anastrophic, and after emerging, continuing for about 1k whorl, then forming a distinct varix, with 2 whorls of the emerging protoconch clearly visible from dorsal view. Dor- sal spiral sculpture is composed of very strong subsutural and peripheral cords, and a promi- nent penultimate cord between, with shallow ex- cavations on either side; 2 minor cords and (on larger specimens) several threads lie within the Arthur S. Merrill and Kenneth J. Boss Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138 excavation between the sutural and penultimate cord. Basal spiral sculpture includes an in- fraperipheral cord with a deep narrow excava- tion between it and the peripheral cord, a very strong cord (basal keel) centrally located at the angulation where the base flattens, a strong crenulated umbilical cord, and 2 weaker cords between the central cord and the umbilical cord; approximately 8 weak threads are formed on the base between the infraperipheral cord and the basal keel. Numerous faint axial lines cut the entire surface of the shell. All cords are strongly elevated, and evenly nodulose. Umbilicus widely open (39-46% of the shell diameter), the walls marked with scaly axial lines. Aperture angular, the peripheral edge slightly bulging and the sides straight. Operculum and animal unknown. Dimensions: Teleo- Proto- Maximum conch Umbilical conch diameter llri:.],t whorls width diameter Holotype 10.2 mm 3.6 mm 4Vs 4.1 mm 0.62 mm Paratype 1 4.0 1.2 2 .- 1.8 0.62 Paratype 2 4.9 1.6 2'- 2 2 0.62 Paratype 3 4.2 1.6 2% 1.6 0.62 Remarks: The shell characters of Pseudotori- nia bullisi place it near P. numulus (Barnard, 1963) of the Indian Ocean (fig. 2, first published photograph of that species); P. numulus has a larger protoconch (0.70-0.76 mm), and there are 3-5 well-developed cords below the infraperi- pheral which are lacking or reduced to occa- sional threads in P. bullisi. In the Atlantic, the Pseudotorinia architae (Costa, 1841) complex displays similar shell 140 THE NAUTILUS October 31, 1985 Vol. 99(4) FIGS. 1-3. 1, Pseudotorinia buliisi n. sp. (holotype USNM 819925; greatest diameter 10.2 mm). 2, Psevdotorinia numulns (holotype of Heliacus numulus Barnard, 1963; SAM A9125; greatest diameter 4.5 mm). 3, Pseudotorinia retifera (holotype of Discohelix (Discosolis) retifera Dall, 1892; USNM 83695; greatest diameter 4.4 mm). characters (fig. 3 shows the type of P. retifera (Dall, 1892), a Pliocene representative of that group from Western Atlantic waters). The suture is not channeled in P. buliisi as in P. retifera, and the major spiral cords are more elevated and more coarsely nodulated, with the axial markings less prominent. In P. retifera the dorsal penultimate cord is closer to the peri- pheral cord and not as deeply excavated be- tween. As in P. numulus, P. retifera has 3 well- developed cords below the infraperipheral which are reduced or lacking in P. buliisi. The um- bilical cord is stronger in P. retifera, but the basal keel is weaker. The upper part of the base is more convex in P. retifera, and more obliquely angled in P. buliisi. Types: Holotype and Paratype 1 of Pseudo- torinia buliisi are in the National Museum of Natural History, Washington (USNM 819925 and 500298), and paratypes 2 and 3 in the Muse- um of Comparative Zoology at Harvard Univer- sity, Cambridge (MCZ 262982). The type locality (holotype and paratypes 2 and 3) is RIV Oregon station 518, about 90 miles southwest of Pensa- cola, Florida (29°23.2'N. Lat.; 88°03.0'W. Long.), at a depth of 82 meters. Paratype 1 is from the Smithsonian University of Iowa Ex- pedition 1918, Barbados station D.3, on a sandy bottom off Pelican Island in 137-146 m. Range: The four known specimens are from off Florida and Barbados in depths of 82-146 m. Etymology: Pseudotorinia buliisi is named for Mr. Harvey R. Bullis, who formerly headed a Bureau of Commercial Fisheries Exploratory Base at Pascagoula, Mississippi. Mollusk material sent by Mr. Bullis from his exploratory missions greatly enhanced Merrill's (1970) study of the Atlantic Architectonicidae. Vol. 99 (4) October 31, 1985 THE NAUTILUS 141 Acknowledgments We are indebted to Dr. Terrence M. Gosliner, formerly at the South African Museum, Cape Town, for the loan of the holotype of Heliacus numulus, and to Mr. Warren C. Blow, Depart- ment of Paleobiology, National Museum of Natural History, Washington, for the loan of the holotype of Discohelix retifera. Photographs were taken by Mr. Victor E. Krantz, National Museum of Natural History. LITERATURE CITED Barnard, K. H. 1963. Contributions to the knowledge of South African marine Mollusca. Part 3. Gastropoda: Prosobranchiata: Taenioglossa. Annals of the South African Museum 47(1):1-199. 37 figs. Bayer, C. 1940. Catalogue of the Solariidae in the Rijks- museum van Natuurlijke Historie. I. Solarium s.s. Zoologische Mededeelingen 22:223-256. 5 figs. Bieler, R. 1984. Morphometrische Analyse der Architeo tonica maxima - Gruppe im Indo-Pazifik (Mollusca: Gastropoda: Architectonicidae). Verhandlungen des NaMrvuissenschafUichen Vereins in Hamburg (NFI 27: 453-492, 8 figs., 7 maps, pis. 1-4. 1985. Die Gattungen der Architectonicidae (Gastropoda: Allogastropoda). Teil 3: Pseudotorinia, Nipteraxis, Heliacus, Eosolarium. Archie fur Molt usken- kunde 116(1-3): [in press]. Dall, W. H. 1892. Contributions to the Tertiary fauna of Florida, with especial reference to the Miocene Silex-beds of Tampa and the Pliocene beds of the Caloosahatchie River, 2.- Streptodont and other gastropods, concluded. Transactions of the Wagner Free Institute of Science of Philadelphia 3(2):201-458, pis. 13-22, 1 map. Merrill, A. S. 1970. The family Architectonicidae (Gastro- poda: Mollusca) in the Western and Eastern Atlantic. Unpubl. Ph.D. thesis, University of Delaware; 338 pp., 42 pis. (University Microfilms International, Inc., Ann Arbor, Michigan; No. 71-6444). A COMMENT ON STROPHITINAE GORDON, 1984 (UNIONIDAE, BIVALVIA) Arthur E. Bogan Department of Malacology Academy of Natural Sciences Philadelphia, PA 19103 The history of the suprageneric taxonomy of unionid bivalves was traced by Heard and Guckert (1971) and by Davis and' Fuller (1981). Haas (1969a, b) provided the latest comprehen- sive supraspecific monograph of the Unionacea but his classification was questioned by Heard and Guckert (1971) and Davis and Fuller (1981). Heard and Guckert (1971:336) noted that Strophitus Rafinesque, 1820, is "more correctly considered as a single group unlike any other subfamily", but included Strophitus in the Anodontinae (Heard and Guckert, 1971:340). Davis and Fuller (1981) did not discuss Strophitus. Gordon (1981:58) in discussing the unionids of Arkansas created the new tribe Strophitini, for Strophitus Rafinesque, 1820. Gordon (1985:8, in footnote to Table 1) raised the Strophitini to subfamilial status, but omitted any discussion or justification for his action. He did not present any arguments about the relationships of this new subfamily to the other subfamilies in the Unionidae. However, neither the taxonomic validity nor the method of publication of Gordon's name Strophitini or Strophitinae are at issue here. Gordon was apparently unaware of a previous use of Strophitinae. Starobogatov (1970:69, 287) erected a new subfamily Strophitinae in the family Lampsilidae for Strophitus Rafinesque, 1820. The following translation of Staroboga- tov's (1970:287) justification for his new sub- family is provided for those who do not have access to the original Russian publication: Subfam. Strophitinae Starobogatov. subfam. n. The shell has a weakened or rudimentary hinge. The beak sculpture consists of lirae (ribbing) which run in almost parallel Inn- <>f gruwth and turn abruptlj upward in the rear. The marsupial pouches occupy the external half of the gills completely. Secondary water tubes during preg- nancy bear the young. Each ovisac is divided by transverse partitions into a series of chambers. Growth is even, the glochidia do not parasitize fish. 142 THE NAUTILUS October 31, 1985 Vol. 99 (4) Therefore, the correct citation of Strophitinae (as well as Strophitini, ICZN Article 36) is Strophitinae Starobogatov, 1970. Acknowledgments I thank James Quinn and Robert Robertson for reviewing the manuscript and commenting on the nomenclature in this paper. Ruth Griffith provided the English translation of the Russian text on Strophitinae; and Cynthia Bogan typed the manuscript. LITERATURE CITED Davis, G. M. and S. L. H. Fuller. 1981. Genetic relation- ships among recent Unionacea (Bivalvia) of North America. Malacologia 20(2):2 17-253. Gordon, M. E. 1981. Recent Mollusca of Arkansas with annotations to systematics and zoogeography. Proc. Ark. Acad. Sci. 34(198):58-62. 1985. Mollusca of Frog Bayou, Arkansas. The Nautilus 99(l):6-9. Haas, F. 1969a. Superfamilia Unionacea. In: Das Tierreich. Berlin, Lieferung 88, pp. i-x, 1-663. 1969b. [Unionacea], pp. N411-N471, In: R. C. Moore (ed.). Treatise on Invertebrate Paleontology, -part N. volume 1, Mollusca 6. Bivalves. Geological Society of America, University of Kansas Press. Heard, W. H. and R. A. Guckert. 1971. A re-evaluation of the recent Unionacea (Pelecypoda) of North America. Malacologia 10(2):333-355. Starobogatov, Ya. I. 1970. [Mollusc fauna and Zoogeograph- ical Partitioning of Continental Water Reservoirs of the World.] Akademiya Nauk SSSR. Zoologischeskii Instituti Nauka. Leningrad 1970, pp. 3-372, 39 fig., 12 tabs. [In Russian!. DISTRIBUTION OF LAMPSILIS POWELLI (LEA) (BIVALVIA: UNIONACEA) Mark E. Gordon Department of Zoology University of Arkansas Fayetteville, AR 72701 ami John L. Harris Environmental Division Arkansas State Highway and Transportation Depart. Little Rock, AR 72203 Lampsilis powelli (Lea, 1852) is a rare and poorly known freshwater mussel associated with the Interior Highlands or Ouachita Mountains of western Arkansas. This species was not included in Burch (1975). In the three published reviews of Arkansas Bivalvia, it was synonymized under Actinonaias ligamentina (Lamarck) by Call (1895) and overlooked by Gordon, et al. (1980) and Gordon (1981). Sub- sequently, L. powelli was monographed by Johnson (1980) including distributional informa- tion based on published accounts and some museum material. Examination of museum specimens, published accounts, and recent col- lecting has enabled us to better delineate the known distribution of this species. The type locality is the Saline River, here restricted to Benton, Saline County, Arkansas. In addition to Lea's specimens (USNM 85042), topotypes were collected by H. E. Wheeler and R. E. Call (UMMZ 91080 and MCZ 5548, respec- tively). Outside Arkansas, Call (1887) reported it from the Spring River at Baxter Springs, Cherokee County, Kansas (MCZ 5550), included a brief description, and compared it to Actinonaias ligamentina. Scammon (1906) simi- larly described a specimen from the Neosho River at Oswego, Labette County, Kansas. Simpson's (1914) locality information appears to be mainly erroneous. Utterback's (1916) and Isely's (1925) records (Neosho basin) were based on identifications from L. S. Frierson (the White River record in Utterback [1917] was a misprint for the 1916 account). Particularly notable are Isely's comments (p. Ill) in reference to his specimens: "52. Lampsilis powellii (Lea)- Mr. Hill reports this species from the Illinois River and has sent me a number of specimens. Frierson suggests that Hill's specimens are either Vol. 99 (4) October 31, 1985 THE NAUTILUS 143 powellii or an undescribed species; he also places some of them near /,. Hijamentina examples of the Neosho as probably powellii." Lampsilis rafinesqueana Frierson (1927) was described from these Illinois River, Oklahoma, specimens. The holotype (female) and a male from the Elk River, McDonald County, Missouri (probably the "L. poivelli" in Utterback, 1916) were illustrated in Frierson (1928). Call's (1887) and Scammon's (1906) descriptions for their L. powelli specimens are readily identifiable as L. niin/isi/iirnini (confirmed by examination of Call's voucher, MCZ 5550). The distinctive ray- ing of the latter species may be obscured or obliterated in older specimens and the shell, par- ticularly males, may be easily confused with A. ligamentina. Johnson's (1980) L. powelli from the Black River, Missouri (MCZ 271445) is an unrayed L. radiata siliquoidea (Barnes) (see Utterback, 1916: Fig. 103A and B). Recently, we have located small populations of Lampsilis powelli in the upper Saline and Ouachita river basins within the Ouachita Moun- tains division of the Interior Highlands of Arkansas (Fig. 1). With the exception of the previously noted topotypes and a lot in the Ohio State University Museum of Zoology (OSUM 21496: fide Stansbery, 1983), these are the only localities for this species which we have been able to substantiate. Considerable past habitat has been inundated by recent impoundments (not shown in Fig. 1) which periodically utilize hypolimnetic discharge. One population is FIG. 1. Distribution (A) of Lampsilis powelli (Lea) in Interior Highlands of Arkansas. presently downstream from DeGray Reservoir, a multi-level release facility, and several others are jeopardized by proposed impoundments. With regards to the above and the restricted range of L. powelli, some protected status ap- pears warranted to ensure the survival of this species. In concordance with Johnson (1980), the shell does resemble L. virescens (Lea), although con- vergence of shell characters may mask true phylogenetic relationships, and may be confused with L. hydiana (Lea), L. radiata siliquoidea, and L. teres (Rafinesque). Distinguishing characteristics between these species were dis- cussed by Johnson (1980). In addition to L. teres, occasional specimens of L. hydiana and L. radiata siliquoidea may also be totally rayless. Generally, the shell of L. powelli is relatively thinner and the posterior ridge of males is more angular than those of the former species. Lamp- silis powelli does sometimes exhibit a super- ficially rayed appearance. This is not pige- mented periostracum, but a curious serial pro- gression of minute pits arranged radially on the shell. Johnson (1980) additionally noted a resemblance toL. reeveiana (Lea); however, this species is not sympatric with L. powelli. Acknowledgments We would like to thank Wendy K. Welch, S. Winters, and Paul J. Polechla for their field assistance and Richard I. Johnson (MCZ) and James Bailey (UMMZ) for the loan of specimens. Partial funding was received from the Arkansas Natural Heritage Commission and the Univer- sity of Arkansas Foundation, Inc. LITERATURE CITED Burch, J. B. 1975. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Malacological Publications, Hamburg, Michigan. 204 pp. Call, R. E. 1887. Sixth contribution to a knowledge of the fresh-water Mollusca of Kansas. Bull. Washburn Coll. Lab. Nat. Hist. 2:11-25. _ 1895. A study of the Unionidae of Arkansas, with incidental references to their distribution in the Mississippi valley. Trans. Acad.. Sci. St. Louis 7:1-65. Frierson, L. S. 1927. A classified and annotated check list of the North American naiades. Baylor University Press, Waco. Ill pp. 1928. Illustrations of Unionidae. The Nautilus 41:138-139. Gordon, M. E. 1981. Recent Mollusca of Arkansas with 144 THE NAUTILUS October 31, 1985 Vol. 99 (4) annotations to systematic* and zoogeography. Proc. Ark. Acad. Sr, 34:58-62. Cordon. M. E.. L. R. Kraemer, and A. V. Brown. 1980. Unionacea of Arkansas: historical review, checklist, and observations on distributional patterns. Bull. Amer. Malacol. Union 797.9:31-37. Isely, F. B. 1925. The fresh-water mussel fauna of eastern Oklahoma. Proc. Okla. Acad. Set. 4:43-118. Johnson, R. I. 198D. Zoogeography of the North American Unionacea (Mollusca: Bivalvia) north of the maximum Pleistocene glaciation. Bull. Mus. Comp. Zool. 149:77-189. Lea, I. 1852. New fresh water and land shells. Trans. Amer. Philos. Soc. 10:253-294. Scammon, R. E. 1906. The Unioniadae of Kansas, pt. 1. Univ. Kans. Sci. Bull. 3:279-373. Simpson, C. T. 1914. A descriptive catalogue of the naiades, nr tin pearly fresh iruter mussel. Bryant Walker, Detroit 1540 pp. Stansbery, D. H. 1983. Some sources of nomenclaturial and systematic problems in unionid mussels. Pages 46-62 in A. C. Miller, compiler. Report of freshwater mussels work- shop, 26-27 October 1982. U. S. Army Engineer Water- ways Experiment Station, Environmental Laboratory, Yicksburg. Utterback, W. I. 1915-1916. The naiades of Missouri. Amer. Midi. Nat. 4:41-53, 97-152, 181-204, 244-273, 311-327, 339-354, 387-400, 432-464. 1917. Naiadgeograph\ of Missouri Amei Midi Nat. 5:26-30. Announcing a New MONOGRAPHS OF MARINE MOLLUSCA Taxonomic revisions of the living and Tertiary marine Mollusca of the world Edited By R. Tucker Abbott ARCHAEOGASTROPOD BIOLOGY AND THE SYSTEMATICS OF THE GENUS TRICOLIA (TROCHACEA: TRICOLIIDAE) IN THE INDO-WEST-PACIFIC Robert Robertson Robert Robertson's "Archaeogastropod Biology and . . . Tricoliidae . . ." Monographs of Marine Mollusca, no. 3, 104 pp., 96 pis $13.50 Monograph no. 1. by R. Houbrick, "Oerithiidae in the Indo-Pacific" (Rhinoclavis, etc.), 130 pp., 98 pis., 3 in color. 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