Bulletins of American paleontology (Bull. Am. paleontol.) Vol 1659

NOV 1931 BULLETINS OF AMERICAN PALEONTOLOGY VOL XVI October r, - November Harris Co Ithaca, U N S N A Y 2, fpji v?»A CONTENTS OF VOLUME XVI Number Pages 59 Some Venezuelan Mollusks By F and H K Hodson 60 Some Venezuelan Mollusks: Part K Hodson By F and 61 An Oligocene Rudistid from Trinidad By F Hodson and G D Harris H i- 94 Plates 1-24 95-132 2536 133-142 37-38 V NOV \ «3\ BULLETINS OF AMERICAN PA LEON TO LOG VOL XVI No 59 October i, 1031 Harris Co Ithaca, N Y U S A BULLETINS OF AMERICAN PALEONTOLOGY Vol 16 Nd 59 Some Venezuelan Mollusks By Floyd Hodson and Helen K October i Hodson , rpji Harris Co Ithaca, N Y U.S A SOME VENEZUELAN MOLLUSKS By Floyd Hodson and Helen K Hodson INTRODUCTION The Venezuelan collections upon which this article is based were made for an American company operating in South America The localities for our Venezuelan holotypes described in and previous articles are given herewith, but the formations which the species are found are withheld at present to protect the company's interests It is hoped that formations, geographic distribution and stratigraphic ranges may be given when the company's interests permit this in The at types are deposited in the collections of Prof G D Harris the Paleontological Museum of Cornell University, Ithaca, N Y Alphabetical List of Species Name Cancellaria Cancellaria Cancellaria Cancellaria Page lavelana H K Hodson, n sp paraguanensis H K Hodson, n sp urumacoensis H K Hodson, n sp venezuelana H K Hodson, n sp Conomitra lavelana F Hodson, n sp Conomitra lavelana falconensis F Hodson, n subsp Conomitra weeksi F Hodson, n sp Corbula (Caryocorbula) buenavistana F Hodson, n sp Corbula (Corbula) carrizalana F Hodson, n sp Corbula (Caryocorbula) democraciana F Hodson, n sp Corbula (Aloidis) gatunensis Toula Corbula (Caryocorbula) quirosana F Hodson, n sp Corbula (Caryocorbula) urumacoensis F Hodson, n sp Corbula (Corbula) zuliana F Hodson, n sp Cymia buchivacoana H K Hodson, n sp Cyrena falconensis H K Hodson, n sp Donax buchivacoana H K Hodson, n sp 44 44 45 45 43 43 43 24 23 26 27 25 25 22 38 18 Bulletin 59 Donax palmasensis H K Hodson, n sp Donax wiedenmayeri H K Hodson n sp Donax wiedenmayeri falconensis H K Hodson, n 19 18 18 subsp H Dosinia falconensis H K Hodson, n sp Iphigenia olssoni H K Hodson, n sp Labiosa (Eaeta) undulata (Gould) Labiosa undulata gardnerae Spieker Labiosa undulata mirandana H K Hodson', n subsp Lueina (Lucinisca) mirandana F Hodson, n sp Macoma (Psammacoma?) democraciana H K Hodson, 19 21 21 22 15 16 16 20 20 14 13 42 42 37 37 n sp Ma.coma (Psammacoma) falconensis H K Hodson, n sp Macoma (Psammacoma) gatunensis Toula (figured only) Mactra californica maracaibensis H K Hodson, n subsp Mactra (Mactro'oma) quirosana H K Hodson, n sp Metis barba wiedenmayeri H K Hodson, n subsp Metis falconensis H K Hodson, n sp Mitra dariensis venezuelana F Hodson, n subsp Mitra quirosana F Hodson, n sp Murex recurvirostris quirosensis F Hodson, n subsp Murex venezuelanus F Hodson, n sp Periploma venezuelana H K Hodson, n sp Periploma venezuelana wiedenmayeri H K Hodson, n subsp Pitaria buenavistana buchivaconna H K Hodson, n subsp Pitaria (Lamelliconcha) circinata (Born) Pitaria rosea wiedenmayeri H K Hodson, n subsp Phos (Phos) buchivacoensis F Hodson, n sp Phos (Antillophos) cocoditoensis F Hodson, n sp Phos (Phos) codorensis F Hodson, n sp Phos (Phos) democraciensis F Hodson, n sp Phos (Phos) falconensis F Hodson, n sp Phos maracaibensis wiedenmayeri F Hodson, n subsp Phos (Antillophos) paraguanensis F Hodson, n sp Phos tuberaensis urumacoensis F Hodson, n subsp Phos (Phos) venezuelensis F Hodson, n sp Phos venezuelensis riocodorensis F Hodson, n subsp Semele laevis costaricensis Olsson Semele quirosana H K Hodson, n sp Semele zuliana H K Hodson, n sp Strombina colinensis H K Hodson, n sp Strombina falconensis H K Hodson, n sp Strombina quirosana H K Hodson, n sp Tellina (Angulus) democraciana H K Hodson, n sp Tellina (Moerella) paraguanensis H K Hodson, n sp Tellina (Moerella) quirosana H K Hodson, n sp Vasum quirosense F Hodson, n sp Xancus aviaguensis H K Hodson, n sp Xancus colinensis H K Hodson, n sp Xancus falconensis H K Hodson, n sp Xancus tirantensis H K Hodson, n sp 10 10 33 35 33 34 34 30 36 31 31 32 17 17 17 29 28 27 13 12 12 41 38 40 40 39 BULLETINS OF AMERICAN PALEONTOLOGY Vol 16 No 61 An Oligocene Rudistid from Trinidad By Floyd Hodson and Gilbert D Harris November 2, rgji Harris Co Ithaca, N Y U.S A AN OLIGOCENE RUDISTID FROM TRINIDAD BY F Hodson and G D Part Harris Prefatory Remarks The finding of Rudistids in the Tertiary, and especially Middle Tertiary, quite a surprise is The matrix of the rock in which they are found and the internal cavities of the Rudistids contain numbers of Oligocene Orbitoids, large especially of the genera Lepidocyclina and Miogypsina, so that there can be no suspicion of redeposition moreover, the nature of the fine sculp; ture preserved on the Rudistid shells would argue against redeposition DESCRIPTION OF NEW GENUS AND GENOHOLOTYPE Neomonopleura The shell companying Hodson and Harris, new genus F has the form and characteristics shown in the acillustrations and is attached by either valve The cup-shaped or strongly twisted there is no indication of "accessory" cavities the upper valve is operculate attached valve is ; ; the shell is rather thin and without canals edentulous or the dentition Genoholotype shell is F of small or (either right or left) is ; the hinge very feeble as the shell N wiedenmayeri, Neomonopleura wiedenmayeri The is n is is probably very thin sp Hodson and Harris, n sp PI 1, figs 1-3; pi 2, figs 1, medium size The attached valve cup-shaped or strongly twisted (the Bulletin 61 136 specimen selected as holotype was attached by the right valve) the body cavity does not show any "accessory" cavities The up; per valve is operculate The shell is rather thin and ornamented with fine radial lines crossed by concentric growth hinge is probably edentulous (or dentition very feeble as the shell is thin The ligamental groove is lines if The present) not deeply im- pressed The above described specimens are very interesting as they are Middle Tertiary representatives of Rudistids, which were supposed to have been extinct since Cretaceous time For a discussion of the associated molluscan fauna, see the chapter on Paleontology by the senior author in Johns Hopkins University Studies in Geology, 1926, p 108 An abundant fauna of Orbitoid foraminifera is found in the matrix Named in honor of Dr C Wiedenmayer, who collected the specimen selected as holotype Middle Oligocene Age Holotype Locality Morne Diablo Quarry No 1, Trinidad — — Plate I Bulletin 61 Plate 138 (37) Page Figure Neomonopleura wiedenmayeri F Hodson and Harris, n sp Paratype "Length" about 50 mm., greatest "diameter" 26 mm Neomonopleura wiedenmayeri F Hodson and Harris, n sp beak 34 mm Same specimen as Neomonopleura wiedenmayeri F Hodson and Harris, n sp Holotype, same specimen as fig Holotype From beak to fig 3 3 PL 7, VOL 16 BULL AMER PALEONT NO 61, PL Plate II Bulletin 61 Plate 140 (38) Figure Paratype Page Neomonopleura wiedenmayeri F Hodson and Harris, n sp "Length" 48 mm., greatest "diameter" 30 mm Same specimen as fig Neomonopleura wiedenmayeri F Hodson and Harris, n sp Paratype Greatest "length" 50 mm., greatest "diameter" 30 mm Same specimen as fig PL 38, VOL "ny^£>