HARVARD UNIVERSITY B® m LIBRARY OF THE Museum of Comparative Zoology BULLETINS OF AMERICAN PALEONTOLOGY VOL. LI 1966- 1967 Paleontological Researcli 1 iistituticin Ithaca, New \()rk U. S. A. IN ME MORI AM C M. Goethe (l,S75-19(i6) Llovd G. CtRinnei l (1894-1966) Hans Burgl (1907-1966) CONTENTS OF VOLUME LI Bulletin No. Plates Pages 231. Descriptions, Ecology, and Geographic Dis- tribution of some Antarctic Pelecypods By David Nicol MO 1-102 232. Genera of the Bivalvia: A Systematic and Bibliographic Catalogue Bv Harold E. Yokes 103-394 IviUS. COMP- ^uuu. LIBRARY NOV 2^ iyb6 BULLETINS u^n;^ers.ty OF AMERICAN PALEONTOLOGY Vol. 51 No. 231 DESCRIPTIONS, ECOLOGY, AND GEOGRAPHIC DISTRIBUTION OF SOME ANTARCTIC PELECYPODS By David Nicol 1966 Paleontological Research Institution Ithaca, New York, U.S.A. PALEONTOLOGICAL RESEARCH INSTITUTION 1966 - 1967 President Donald W. Fisher Vice-President Kenneth E. Caster Secretary-Treasurer Rebecca S. Harris Director Katherine V. W. Palmer Counsel Arm and L. Adams Representative AAAS Council Kenneth E. Caster Trustees Kenneth E. Caster (1960-1966) Katherine V. W. Palmer (Life) Donald W. Fisher (1961-1967) William B. Heroy (1963-1968) Rebecca S. Harris (Life) Axel A. Olsson (Life) Daniel B. Sass (1965-1971) Hans G. Kugler (1963-1969) W. Storrs Cole (1964-1970) BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA Katherine V. W. Palmer, Editor Mrs. Fay Briggs, Secretary Advisory Board Kenneth E. Caster Hans Kugler A. Myra Keen Jay Glenn Marks Axel A. Olsson Complete titles and price list of separate available numbers may be had on application. For Vols. 1-23, Bulletins of American Paleontology see Kraus Reprint Corp., 16 East 46th St., Nev? York 17, N.Y., U.S.A. For reprint, vol. I, Palaeontographica Americana see Johnson Reprint Corporation, 111 Fifth Ave., New York 3, N.Y., U.S.A. Subscription may be entered at any time by volume or year, with average price of $16.00 per volume for Bulletins. Numbers of Palaeontographica Amer- icana invoiced per issue. Purchases in U.S.A. for professional purposes are deductible from income tax. For sale by Paleontological Research Institution 109 Dearborn Place Ithaca, New York U.S.A. BULLETINS OF AMERICAN PALEONTOLOGY (Founded 1895) Vol. 51 No. 231 DESCRIPTIONS, ECOLOGY, AND GEOGRAPHIC DISTRIBUTION OF SOME ANTARCTIC PELECYPODS By David Nicol University of Florida Gainesville, Florida November 15, 19()() Paleontological Research Institution Ithaca, New York, U.S.A. MUS. COMP. ZOOL> LIBRARY NOV 29 1966 UNIVERSITY Library of Congress Catalog Card Number: GS66-138 Printed in the United States of America CONTENTS Abstract 5- Introduction 5- Acknowledgments 7 The Ross Sea pelecypod fauna 8 Geographic distribution of the species studied 8 Systematic description of the Pelecypoda 11 Subclass Protobranchia II Order Xuculoida H Nuculanidae 11 Malletiidae 17 Subclass Polysyringia 18 Order Prionodonta 18 Limopsidae 18 Order Anisomyaria 25- Mytilidae 2!> Philobryidae 27 Pectinidae 40 Limidae 43 Order Eulamellibranchia 47 Astartidae 47 Carditidae 49 Cyamiidae 51 Neoleptonidae 59 Thyasiridae fil Erycinidae 65 Montacutidae 67 Lyonsiidae 69 Thraciidae 71 Laternulidae 74 Subclass Septibranchia 76 Order Poromyoida 76 Cuspidariidae 76 Literatine cited 79 Plates 87 DESCRIPTIONS, ECOLOGY, AND GEOGRAPHIC DISTRIBUTION OF SOME ANTARCTIC PELECYPODS David Nicol University of Florida Gainesville, Florida ABSTRACT The collection of antarctic pelecypods at the United States National Museum consists of 451 lots which contain approximately 2,550 specimens allo- cated to 36 species. All of the material came from relatively shallow water, and no station was deeper than 1,097 m. The pelecypod families best represented in this collection arc the Nuculaniilae with three species, the Limopsidae with three species, the Philobryidae with six species, the Cyamiidae with five species, and the Thyasiridae with three species. The Limopsidae, the Philobryidae, and the Cyamiidae do not occur in the shallow-water arctic pelecypod fauna. Of the 36 species studied, 15 have both a subantarctic and circimiantarctic distribution. Eleven of the species are confined to the circumantarctic. Seven of the species studied appear to be antarctic endemics (i.e., not found throughout the entire antarctic region). Only three species occur in the Palmer Peninsula and adja- cent areas of the subantarctic but not in the rest of the antarctic region. The new genus Waldo is proposed with Lepton parasiticum Dall, 1876, as the type species. INTRODUCTION The collection of antarctic pelecypods in the Division of Mollusks at the U.S. National Museum consists of 451 lots which contain approximately 2,550 specimens allocated to 36 species. The material was obtained by the efforts of several expeditions and col- lectors. These are enumerated beginning with the oldest, and stating the number of lots of pelecypods obtained by each expedi- tion or collector: U.S. Antarctic Service Expedition, March 1940, 1 lot; U.S. Navy (Operation Windmill), December 1947 to February 1948, D. C. Nutt, collector, 2.S lots; Deepfreeze I Expedition, Janu- ary-March 1956, }. Q. Tierney, collector, 37 lots; Deepfreeze II Ex- pedition, October 1956 to March 1957, W. H. Littlewood, J. Q. Tierney, and W. L. Tressler, collectors, 60 lots; Deepfreeze III Ex- pedition, December 1957 to February 1958, W. H. Littlewood, L. Wilson, J. Q. Tierney, and R. B. Starr, collectors, 97 lots; Deepfreeze IV Expedition, January-April 1959, J. Tyler and L. Wilson, collec- tors, 54 lots; Deepfreeze 1960-1961 Expedition, December 1960, J. Q. Tierney, collector, 8 lots; Dr. John H. Dearborn's collections made in the Ross Sea region (other collectors contributed or assisted Dear- born) , November 1958 to December 1961, 106 lots; Waldo L. Schmitt's collections in the Palmer Peninsula region, fanuary to March 1963, 65 lots. All of these exjieditions exce|Jt for tlic first one contributed valuable material iov this study. In this large collection of antaic tic pelecypods, foiu" species are represented by only one specimen each. On the other hand, there Bulletin 231 are as least 100 specimens of the following species: Yoldia (Aeqvi- yoldia) eightsi, Limopsis niarionensis, Philobrya suhlaevis, Lissarca notorcadensis, Adacnarca Jiiteyis, Adamussium colbecki, Limatida hodgsoni, Cyclocardia astartoides, and Thracia merldionalis. There is no direct correlation between number of lots (stations) and num- ber of specimens of each species. There are 16 lots but only 37 speci- mens of Malletia sabrina whereas there are 21 lots containing 175 specimens of Yoldia (Aequiyoldia) eightsi in the collection. There are 9 lots containing 10 specimens of Limopsis lilliei, and there are 9 lots containing 24 specimens of Dacrydiinn aJbiduni. The most puzzling species are those found at a large niunber of different sta- tions but with only one or two specimens in each lot. These species are widely dispersed but are not abundant at any one locality. Many widely dispersed species of pelecypods are abundantly represented at most localities. In a species like Limopsis lilliei, it is not easy to understand the populaton mechanics in its widely dispersed but sparse distribution. The material was all collected from relatively shallow water. The deepest collecting station was 1.097 m, where 4 of the 36 species ^ere found. No other station measured more than 836 m. Four species were found only at depths of less than 100 m, including a few specimens which Dr. Waldo L. Schmitt picked up along the shore in the Palmer Peninsula area. Adaenarca nitens has the greatest depth range of any of the species in the U.S. National Museum col- lection— 15.5 m to 1,097 m. There are three reasons why there are only 36 species of ant- arctic pelecypods represented in the mollusk collection at the U.S. National Museum. There is only one collecting station deeper than 836 m, and the writer is certain that a few more species could have been obtained by additional collecting at greater depths. No col- lections were made from the South Shetlands and South Orkneys, which probably have the richest pelecypod fauna in the entire ant- arctic region, and not enough collecting was done in the Palmer Peninsula area. Almost no collecting was done in the eastern ant- arctic—the Davis Sea region and the Enderby Quadrant. Nearly all of the specimens in the collection were found in the Weddell Quadrant and the Ross Sea, including the western part of the Vic- toria Quadrant. Powell (1960) listed 93 species in his antarctic Antarctic Pelecvpods: Nicol mollusk catalogue (not including species preceded by a question mark, subspecies, and all species reported only in depths greater than 1,829 m) . Some of these species have been synonymized, and the writer feels confident that the 36 species in the collection at the U.S. National Museum represent half of all the species of pelecypods living in the shallower waters of the antarctic region. ACKNOWLEDGMENTS This project has been supported financially by a grant from the National Science Foundation (G-13335) and additional money supplied by the Smithsonian Institution for research during July and August, 1965, through I. E. Wallen. The cost of the engraving of the plates was met by the University of Florida. The writer is particularly indebted to Joseph Rosewater, As- socia...
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