Bulletins of American paleontology (Bull. Am. paleontol.) Vol 343

^MSctms of rxcan auontolccisi Begun OLUME 105, in 1895 OCTOBER NUMBER 343 Jurassic and Cretaceous Trigoniid Bivalves from West-Central Argentina by Hector A Leanza Paleontological Research Institution 1259 Trumansburg Road New York, 14850 U.S.A Ithaca, 20, 1993 Gilbert Dennison Harris (1864- 1952) Founder of the Bulletins of American Paleontology (1895) ISBN 0-8771 0-42' PALEONTOLOGICAL RESEARCH INSTITUTION Officers President Vice-President J Thomas Dutro, John Jr C Steinmetz Henry W Theisen Annika Farrell Warren D Allmon Secretary Treasurer Director Trustees Samuel T Pees (to 6/30/95) Richard E Petit (to 6/30/96) Gary Rosenberg (to 6/30/96) James E Sorauf (to 6/30/94) John Steinmetz (to 6/30/94) Susan B Stephens (to 6/30/96) Henry W Theisen (to 6/30/95) Raymond Van Houtte (to 6/30/94) Tucker Abbott (to 6/30/96) Bruce M Bell (to 6/30/96) Carlton E Brett (to 6/30/95) R Ann F Budd William (to 6/30/94) Crepet (to 6/30/94) Thomas Dutro, Jr (to 6/30/96) J Annika Farrell (to 6/30/96) Robert M Linsley (to 6/30/95) Peter McLaughlin (to 6/30/95) L BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA Warren D Allmon Editor Reviewers for this issue Terrence A Cathryn Poulton P E Newton both series, and available numbers and volumes may be had on request Volumes 1-23 of Bulletins of American Paleontology have been reprinted by Kraus Reprint Corporation, Route 100, Millwood, New York 10546 USA Volume of Palaeontograpliica Americana has been reprinted by Johnson list of titles in Reprint Corporation, 1 Fifth Ave., New York, NY 10003 USA Subscriptions to Bulletins of American Paleontology may be started at any volume or year Current price is US $45.00 per volume Numbers of Palaeontographica Americana are priced individually, and are invoiced separately time, by on request for additional information, write or call: Paleontological Research Institution 1259 Trumansburg Road Ithaca, NY 14850 USA (607) 273-6623 FAX @ This (607) 273-6620 paper meets the requirements of ANSI/NISO Z39 48-1992 (Permanence of Paper) ^ VOLUME msqf "'{can rid Begun 105, NUMBER 343 in 1895 ^^^"^ OCTOBER Jurassic and Cretaceous Trigoniid Bivalves from West-Central Argentina by Hector A Leanza Paleontological Research Institution 1259 Trumansburg Road New York, 14850 U.S.A Ithaca, 20, 1993 ISSN 0007-5779 ISBN 0-87710-430-1 Library of Congress Card Number: 93-085393 Printed in the United States of America Allen Press, Inc Lawrence, KS 66044 U.S.A CONTENTS Page Abstract Introduction Comments on the Family Trigoniidae Geological settmg of the trigoniid bearing strata in west-central Argentina Temporal distribution of trigoniid bivalves in west-centra! Argentina Lower Jurassic species Middle Jurassic species Upper Jurassic species Lower Cretaceous species Upper Cretaceous species 9 10 11 11 12 Species durations of the Family Trigoniidae in west-central Argentina 12 Acknowledgements 14 Introduction to systematic paleontology 14 Philosophical considerations 14 Terminology Measurements and abbreviations Abbreviations of repository institutions 16 17 18 18 Systematic descriptions Plates 65 68 74 Index 91 Appendix; Fossil References Cited localities of the described taxa and associated fauna LIST OF ILLUSTRATIONS ^^^^ Text-figure Location of fossil localities Schematic stratigraphic section for the Jurassic and Cretaceous of west-central Argentina Morphological terminology used to describe tngoniid bivalves in this paper LIST OF TABLES P^ee Table and Cretaceous Stratigraphic distribution of Jurassic and Cretaceous Stratigraphic distribution of Jurassic 17 trigoniid bivalves in west-central Argentina, in stratigraphic order 13 trigoniid bivalves in west-central Argentina, in systematic order 15 AND CRETACEOUS TRIGONIID BIVALVES FROM WEST-CENTRAL ARGENTINA JURASSIC By Hector A Leanza' With the contribution of Jose I Garate Zubillaga- ABSTRACT subspecies of precisely dated Trigoniidae from the Lower Jurassic (Liassic) to the This monograph describes 73 species and Upper Cretaceous (Maastnchtian) of western central Argentina These are classified into subfamilies as follows: Minetngoniinae, Trigoniinae, Neuquenitngoniinae, n subfam., Frenguelliellinae (emend.), Myophorellinae, Vaugoniinae, Steinmanellinae, An1 ditrigoniinae, n subfam., Megatrigoniinae, Buchotrigoniinae, n subfam., Pterotrigoniinae, Laevitngoniinae, Austrotrigoniinae and Nototrigoniinae The Frenguelliellinae are reinterpreted to range in age from the Triassic to the Middle Jurassic (Bajocian), and include only the genera Frengueltiella and Kumatngoma Neuquenitngoniinae, n subfam., include the very specialized Middle Jurassic genus Seuqucnitrigonia which shows a transversely costate flank and escutcheon, characteristics that are absent in Trigoniinae s.s Anditrigoniinae, n subfam., is erected to group the Middle Jurassic to Lower Cretaceous genera and subgenera Eoanditrigonia n subgen., Anditrigoma, Parandhngoma, Antulrigoma, Virgolngoma, and Lambertngoma n gen., which are characterized by an smooth area in early representatives, or by transverse or radial ornamentation, or a combination of both, and a poor to well developed marginal carina The Buchotrigoniinae n subfam include the very specialized Lower Cretaceous genera Buchotngonia and Syrotngoma which are characterized by a tripartite development of oblique, subconcentric and The subvertical costae on the flank treated genera are twenty one, including: Groeberella, n gen (type species: Myophoha neuquensis Groeber, 1924), Tngonia FrenguelUella Jaworskiella Myophorella Scaphotngonia, Scaphorella Neuquemtngonia, Vaugoma, Andimugoma, n gen (type species: Tngonia radixscnpla Lambert, 1944), Sleinmanella, Virgotrigonia, Lambertrigonia, n gen (type species Tngonia pichimoncolensis Lambert, 1944), Anditrigonia, Antulngonia, Rutitngonia, Syrotngoma, Pterotngonia Quoiecchia Auslrotngonia and Pacitngonia stricto, The genus Myophorella Promyophorella and Haidaia The genus Sleinmanella is divided into the subgenera Myophorella sensu represented by the subgenera Transitngonia, Macrotngonia, is and Splendilngonia, n subgen (type species: Tngonia splendida A F Leanza, 94 ) Anditrigonia is represented by Anditrigonia stricto, and by an early representative, Eoanditrigonia n subgen (type species: Trigonia keideli Weaver, 1931) The Upper Jurassic and Cretaceous genus Pterotrigonia is divided into the subgenera Pterotngonia sensu stricto, Scabrotrigonia, Rinetrigonia, and Notoscabrotngonia Ten new species and one new subspecies are established, as follows: FrenguelUella pouhoni (Liassic)i Trigonia losadai, Trigonia leyyi, FrenguelUella perezreyesi and Scaphorella camachoi (Middle Jurassic); Myophorella (Myophorella) schulzi Myophorella (Haidaia) elgiietai Pterotngonia (Notoscabrotngonia) coheni and Anditrigonia (A.) eximia tesselicaudata (Upper Jurassic); Rutitngonia kaiiffniani and Syrotngoma brocardoi (Lower Cretaceous) Comments on the Family Trigoniidae, as well as taxonomic considerations, stratigraphic occurrence, and facies relationships of the described species are presented With the new taxonomy proposed here, the trigoniids have a much greater temporal 1 sensu resolution than previously thought, especially at the species level RESUMEN En la presente monografia se describen 73 especies y una subespecie de Trigoniidae precisamente datadas del Jurasico inferior (Liasico) al Cretacico superior (Maastnchtiano) del oeste central de la Argentina Estas se clasifican en 14 subfamilias a saber: Minetrigoniinae, Trigoniinae, Neuquenitrigoniinae, manellinae, Anditrigoniinae, n trotrigoniinae y Nototrigoniinae el Jurasico incluye al Medio muy caracteristica que subfam., Frenguelliellinae (emend.), Myophorellinae, Vaugoniinae, Stein- La subfamilia Frenguelliellinae n esta ausente en Trigoniinae el Jurasico Antutngonia, \'irgotngonia s.s subfam., Pterotrigoniinae, Laevitrigoniinae, Ausedad desde el Triasico hasta se reinterpreta extiendiendose en (Bajociano), e incluye solamente los generos FrenguelUella y especializado genero del Jurasico extienden desde n subfam., Megatrigoniinae, Buchotrigoniinae, Kumatngonia Neuquenitrigoniinae, Medio Neuquemtngonia que muestra Anditrigoniinae, n subfam se erije n subfam costulacion transversal en area y flanco, para agrupar generos y subgeneros que se Medio al Cretacico Inferior, tales como Eoanditrigonia n subgen Anditrigonia Paranditrigonia and Lambertngoma n gen., que se caracterizan por areas lisas en representantes tempranos, o por o una combinacion de ambas y una debil a bien desarrollada carena marginal Buchespecializados generos del Cretacico Inferior Buchotngonia y Syrotrigonia que se caracterizan por un desarrollo tripartito de costillas obliquas subconcentricas y subverticales sobre los flancos Los generos tratados son veintiuno, incluyendo: Groeberella n gen (especie tipo; Myophoria neuquensis Groeber, 1924), Trigonia, Fren- una omamentacion transversal o radial, otrigoniinae, n subfam., incluye los Secretaria de Mineria Museo Juan Member muy of the National Research Council (CONICET) Av Julio A Rosa 651 1067 Buenos Aires Argentina Olsacher Direccion General de Mineria Olascoaga 421 8340 Zapala Neuquen Argentina Bulletin 343 Myophorella Scaphotrigonia, Scaphorella Neuquenithgonia Vaugonia, Andivaugonia, n gen (especie radixscnpla Lambert, 1944), Sleinmanella Virgotrigonia, Lambertrigonia, n gen (especie tipo: Trigonia pichimoncolensis Lambert, 1944), Andithgonia, Antutngonia Rutitrigonia, Syrotrigonia, Pterothgonia, Quoiecchia, Austrolrigonia, and Pacirrigonia El genero Myophorella se divide en los subgeneros Myophorella sensu stricto, Promyophorella, y Haidaia El genero Sleinmanella esta representado por los subgeneros Transitrigonia, Macrotrigonia, y Splenditrigonia n subgen (especie guelliella, Jaworskiella tipo: Trtgonia Tngonia splendida A F Leanza, 1941) Anditngonia esta representado por los %\x\>%ineTos Anditrigonia sensu stricto, y por un representante temprano, Eoandilrigonia n subgen (especie tipo: Trigonia keideli Weaver, 1931) El genero Pterotrigonia tipo: caracteristico del Jurasico Superior y Cretacico se divide en los subgeneros Pterotrigonia sensu stricto, Scabrotrigonia, Rinetrigonia, and Notoscabrotrigonia Se establecen diez nuevas especies y una nueva subespecie a saber: Frenguelliella poulloni (Liassico); Trigonia losadai, Trigonia levyi, Frenguelliella perezreyesi, y Scaphorella camachoi (Jurasico Medio); Myophorella (Myophorella) schuhi, Myophorella (Haidaia) elguetai, Pterotrigonia (Noloscabrotrigonia)coheni y Anditngonia (A.) eximia tesselicaiidata n ssp (Jurasico Superior); Rutitrigonia kaujfmani y Syrotrigonia brocardoi (Cretacico Inferior) Se efectuan comentarios sobre la Familia Trigoniidae, asi como consideraciones taxonomicas, distribucion estratigrafica, y relaciones de facies de las especies descriptas Segun la nueva taxonomia propuesta, los trigonidos muestran una resolucion temporal de la que se creia previamente, especialmente al nivel de especie INTRODUCTION 20 years from 41 different This revision of the Trigoniidae from west-central Argentina was necessary in order to update the taxonomic knowledge of this interesting group of bivalves, and to improve the Jurassic and Cretaceous biostratigraphy and paleontology of the southern Andes The first description of trigoniids in west-central Argentina was made by Gottsche (1878), based on fossils from Espinacito Pass in the High Cordillera of San Juan Province The knowledge of the family in this region was later improved by Behrendsen ( 89 1-1 892), Tomquist (1898), Burckhardt (1900a, 1900b, 1901, 903) Haupt ( 907), Douville (1910), Jaworski (1916, 1925, 1926), Groeber (1924), Weaver (1931) and A F Leanza (1941, 1942) published the first It was Lambert (1944) who paper exclusively dedicated to tri- Neuquen Province, describing a total of 24 species Levy (1966, 1967a, 1967b, 1967c 1969, 1985) published a number of papers devoted to the goniids from taxonomic revision of the Argentine trigoniids, and Marifielarena (1959) described an Upper Jurassic species from Neuquen Camacho (1967 1968) described Upper Cretaceous trigoniids, and Camacho and Riccardi (1978) published a list of fossil invertebrates from Neuquen including an updated list of trigoniid bivalves In recent years, Camacho and Olivero (1985), Leanza(1981, 1985), Leanza and Garate(1983a, 1983b, 1985, 1986, 1987), Leanza, Perez and Reyes (1987), Manceiiido and Damborenea (1984), Farinatti, Quattrocchio and Labudia (1987), and Leanza and Casadio (1991) described several species mainly from the Jurassic and Cretaceous of the Neuquen Basin The present monograph includes the description and taxonomic revision of 73 species and one subspecies of trigoniid bivalves Of these, species have been collected in Neuquen Province, one species is common both in Neuquen and La Pampa Provinces, and the remaining two taxa were found in La Pampa Province The studied material has been collected over the past mucho mayor fossil localities (Text-figure In the systematic descriptions, a concise diagnosis 1) provided for each genus and/or subgenus, and a is added in the case where new morphologic information or new taxa are described New concepts of trigoniid morphology and descriptive features, which are valuable in differentiating taxa, are included in the is discussion systematic descriptions, such as the dorsoposterior and ventroposterior angles or junctions (Kauffman et al in preparation); these parameters better define the shell shape of each species than those previously used Charornamentation of the area (see Terminology, p 16) were especially taken into account when distinguishing species or even genera and subgenera acters of the (Perez and Reyes, 1987) Many previous trigoniid workers (e.g Cox, 1952, 1969; Nakano, 1960) have been conservative in their approach to higher taxonomic division of the Trigoniaceae, but more detailed morphologic analysis in this study has allowed new revisions at the subfamily level Taking as a point of departure the interpretations of the family by van Hoe- pen (1929), Kobayashi (1954), and Saveliev (1958), 13 subfamilies, two of them new, are herein distinguished Species duration may be as little as one million years for 27% of the described trigoniid species; the average is 3.8 million years species duration COMMENTS ON THE FAMILY TRIGONIIDAE Trigoniidae, generally the group Lamarck (1819), had a cosmoof of "les trigonees" the Mesozoic During throughout politan distribution diversity of form immense developed they this time The bivalve family and external sculpture, which is reflected in a large number of genera and species described from every continent The family is characterized by a peculiar paleoheterodont dentition and by varied, highly ornate, thick shells of trigonal shape The superfamily Trigoniaceae, which includes both Trigoniid Bivalves of Argentina: Leanza Bulletins OF American Paleontology, Volume 105 Plate 15 ^t^M'tA^ , Plate 16 Bulletins of American Paleontology, Volume 105 l/]^'^ ^^A ^^ ^^^i^-y3^^ -^^t- » ^ 10 Trigoniid Bivalves of Argentina: Leanza Explanation of Plate 89 (All figures natural size, unless otherwise indicated) Figures Page 1-3 Ruiitngonia agnoensis (Weaver) 54 Hypotype, MOZ P0920/3, lateral view of left valve; dorsal view of same specimen 3, Hypotype, MOZ P0920/1, view of left valve Lower Hauterivian, Agrio Formation, Cerro Negro Chico de Picun Leufii (Locality 18) 1, 4, 7, 10, 12 Syrolrigonia brocardoi 4, Paratype, II Type, MOZ P5236, lateral view of left valve; dorsal view of 49 same specimen Middle Hauterivian, Agrio Formation, Arenal dc Las Lajas (Locality 28) Plcrolngonia (Rinetiigonia) coihuicoensis (Weaver) Hypotype, 61 MOZ P5313, anterior view of both valves; 9, lateral view of left valve of same specimen; 1, dorsal view of same specimen Middle and Upper Hauterivian, Agrio Formation, Cerro Mesa, Covunco (Locality 8) Slcinmanella (Macrolngonia) vacaensis (Weaver) 13, Hypotype, MOZ P2329, anterior view of both valves, with a probable byssal slit below the beaks Middle Hauterivian, Agno Formation, Los Homos, Covunco (Locality 29) 6, P5318, dorsal view 7, lateral view of right valve of same specimen 10, Holotype, MOZ P5319, dorsal view of left valve of same specimen Lower Hauterivian, Agrio Formation, Pichaihue Abajo (Locality 3) Anditrigonia (Andilrigonia), species indeterminate 5, 6, 9, 57 species MOZ view; 12, lateral 5, new lateral 45 Bulletin 343 90 Explanation of Plate (All figures natural size, unless otherwise indicated) Page Figures , Holotype, GHUNLPam 399, dorsal view showing radial costellae on the area; Maastrichtian Jagiiel Formation Barda Baya, La Quoiecchia 3, original sigeti 64 and Casadio 1,2 Pacilrigonia sobrali Leanza Pampa 2, lateral view of left valve of same specimen (Locality 41) 63 Leanza and Garate Paratype, MOZ P 0/ lateral view of right valve 1 Lower Hauteri vian, Agrio Fomation, Pichaihue Abajo (Locality 3) 4, Aiislrotrigonia 4, Holotype, 63 pampeana Leanza and Casadio GHLINLPam 400 lateral Barda Baya La Pampa (Locality view of right valve; dorsal view of same specimen Maastrichtinan, Jagiiel Formation, 5, 41) 24 7-10 Trigonia wiedinanni Leanza and Garate 7, Holotype, view; 10, lateral (Locality 6, 1-1 P0942/1, dorsal view; 8, lateral view of right valve of same specimen 9, Paratype MOZ P0942/2, dorsal view of left valve of same specimen Lower and Middle Hauterivian, Agrio Formation, Cerro Negro, Covunco MOZ 9) Pterotngonia (Rmctrigonia) windhauscmana (Wilckens) P23 17/1, lateral view of right valve 6, Hypotype, MOZ MOZ P2317/2, (Locality 27) lateral view of left 62 1 Hypotype, valve; 13, dorsal view of MOZ P23 17/3, lateral view of left valve same specimen Maastrichtian, Jagiiel 12, Hypotype Formation, Cerro Villegas Bulletins of American Paleontology, Volume 105 Plate 17 ^'^-'' *' ^«^ J 10 Trigoniid Bivalves of Argentina: Leanza 91 INDEX (Bold numbers to pages in refer to plates in which a taxon is which a taxon is illustrated; italic numbers refer to pages in which a taxon is described; plain numbers refer cited) B bajuranasi abnipla 56,57 Buchorrigonia 31 Myophorella 12,14,54.16,55.56 Rutitrigonia 64 Paciirigonia 62,63 Quoiecchia 8,12,17,23,24.10 Trigonia 11,14,55,14,59 Ptewlngonia 10,11,12,16,36,38,46.47,60,51,52,53,54,57 carrincurensis 1,12,46,47.5,48 49 discors eximia lamherli 57 47 12,49.16 11,12,49.9 sp.juv indet 45,54 Anditrigoniinae covuncoensis 10,36,i7,38,39,40 10,14,38,i9.4,40 fuenzalidai 10,14,38,i9.4 lissocostata 10,12,38,.?9.4,40 radixscripta 10,14,37,iS.4,39 29 Trigonia aff angusta 48 Trigonia 12,22,23,24.13,25,27 63 11,16,46,50.51,52 frenguellii groeberi Apiolrigonia 1,14,5/.8,52 Scaphogonia Trigonia 17,36,63 carinata 8,1 1,14,22.7,23,24 Trigonia carrincurensis Andilrigonia 1,12,46,47.5,48 24 Trigonia 10,14,29.2 Myophorella 57 Syrolrigonia chunumavensis Vaugoma 10,12,i6.2,37,38,53 chacaicoensis 47 29 coheni 11,14,59.6,60 Plerolrigonia 10,14,29.1 coihuecoensis 10,12,i0.2 conocardiiformis Plerolrigonia Trigonia 34,35 31 2, 14,6/, 16, 62 48 aff consangiiinea 48 Trigonia corderoi 48 56 costata 59 costatula Trigonia Trigonia attenuala Plerolrigonia aliformis var 62 Plerolrigonia Cardiidae Trigonia arnisoe Asialolrigonia 10,12,i5.3 Scaphorella capricornia Clavilngonia argo Myophorella cf camachoi 1,12, 50, 5/ 13 argentinica Myophorella 62 Plerolrigonia 11,14,51,52.8 araucana Myophorella 10,14,25.1 Jaworskiella hustamantina chilensis Apiotrigoniinae opislolophophora burckhardti calenifera angustecostata Antutrigonia 56,57 cassiope angiilala Trigonia subfam 11,12,46,49.9,50 sp indet Andivaugoma n 1,14,16,47,45.9,50 plumasensis Austrotrigoniinae 56,57 57 sp Buchotrigoniinae aliformis secunda 36,56,57 abrupta topocalmensis aliexpandita prima 12,57,16,58 Syrolrigonia Buchotrigonia aliciae pampeana 53 Turbitrigonia brocardoi alamensis Auslrolrigonia 57,58 Syrolrigonia houdiccae agrioensis Andilrigonia 20 Trigonia biroi agniaensis 12,6i,64 12,14,6i,17,64 63,64 64 63 "Trigonia" 10 14,3,4,5, 79.20,21 10,21 27 covuncoensis Andivaugonia 10,14,38,i9.4,40 crassidens Trigonia 48 Bulletin 343 92 garatei crassitesla 37 lotrigonia Myophorella 12,i/, 12,32 gerthi crenutata 33,34 Myophorella 60 Pterotrigonia 57,58 Syrotrigonia cristata Pterotrigonia 58 gottschei I'augonia 38 59 Groeberella 9,10,/S,19 cuhanica Pterolrigonia 9,10,14,/S,1,19 neuqtiensis curacoensis 42 Trigonia iransitoria var 12,79,3 sp indet groeheri D Antutrigonia 11,14,51,52.8 gryphitica dawsoni Haidaia 32 H 36 Thgonellina densestriala 10, 12,2/, 3,23, 27 Trigonia discors 28 Trigonia delicata Haidaia dawsoni 1,12,16,32,33,60,62 32 hanetiana A ndilrigonia 49 dislans 64 Pacitrigonia haupti 57 Trigonia diversicoslala Sleinmanella 11,14,40,43,44.6,45 hcrzogi 53 Trigonia 45 Steinmanella Heterotrigonia E 52,53,54,63 hillebrandti Myophorella elegans 33 Myophorella 40 Steinmanella elguelai Myophorella l,12,ii,9,34 6,46.47 Trigonia huenickeni keideli hondeana 11,14,46,47.2 Eoanditrigonia Eolrigonia 0, 41,44 epizoans 44 Neuquenitrigonia 10,12,25,3,26 hugoi Virgotngoma eufalensis l,12,i2,8 holubi l,14,37,5i.l4,59 32 Myophorella I erycina Sleinmanella 1,12,40,43,44.7,45 inexspectata 1.14,16,47,45,9,50 lotrigonia eximia 10,14,26,2 Frenguelliella Anditrigonia exotica 36,37,38,46,52,57 37 crassitesla 38 Vaugonia 52 lotrigoniinae F J feruglioi 62 Pterotrigonia 9,10,28 Jaworskiella 10,14,25,1 hurckhardti fortinensis 11,12,2,^.6,25 Trigonia K fuenzalidai 10,14,38,iy.4 Andivaugonia 56,57 Syrotrigonia 9,10,17,26.27 Frenguelliella 10,14,26.2 mexspectata 10,12,21,27,2 perezreyesi 10,26.2,27 poulloni sp kauffmani 12,14,55.15,56 Rutitrigonia fraasi B 26,27 10,26,1,27 tapiai kalterfeldensis Eoanditrigonia 1,14,46,47,2 56 Korohkovilrigonia kruusei 10,12,i5,3,36 Scaphorella 26 Frenguelliellinae L frenguellii Antutrigonia 1,14, 5/ 8, 52 Laevitrigonia Laevitrigoniinae G 63 62,63 lamberli gampsorrhyncha Trigonia 45 Steinmanella keideli Anditrigonia 48 Lambertiella 11,12,46,49.9,50 37 Trigoniid Bivalves of Argentina: Leanza Lamherlrigonia pichimoncolensis N 1,16,36,46,52, 5i,54 11,14,22,52,52,53,54.5 leanzai navis 34 Trigonia 10,14,i4,3,35,36 Scaphoretla levyi Neolrigonia margarilacea Trigonia 1,12,22,6,23 lihanotica neuquensis 10.12,38,i9.4,40 neuquensis tissocostata literata 47 Trigonia losadai lycetti 1,14,40,42.12 42 aff nodulosa 28 Myophorella 38 Vaugonia Lycetlia Notoscabrotrigonia oliveroi Nototrigoniinae M 1,59,60 64 64 64 Nololrigonia 41,44 epizoans on 7,25 9,10,14./S.1,19 Sleinmanella nodosa Trigonia 10,14,205,21 Trigonia 25,26 Groeberella Andivaugonta 0, 10,12,25,3,26 Neuquenitrigoniinae 56 Lmotrigonia O macrorrhyncha 48 Trigonia Macrotrigonia 1,12,40,45 manflarum oliveroi 64 Nololrigonia opislolophophora 38 Trigonia Maputrigonia margaritacea Aniulrigonia 1,12,50,57.13 1,46,52,53,54 P Neolrigonia pampeana maxima 45 Sleinmanella Myophorella Mediterraneotrigonia Austrolrigonia 12,14,6i.l7,64 Pacilrigonia 12,64 30 alamensis 44 haneliana 64 64 64 mearnsi Megalrigonia 46,57 palagonica Megatrigoniinae 46,57 sohrali Minelrigoniinae 18 sylvesleri 12,14,64,17 64 palagonica mirundaensis Trigonia 1,2/, 5, 22 Pacilrigonia 64 paradisensis mollesensis Trigonia 10,14,19,20,2,21 Syrolrigonia aff Syrolrigonia muhicostata 49 Trigonia eximia var Myophorella Neitquenilngonia Inwmckcni 56,57 Syrotrigonia 9,10,11,12,16,25,29,30,31,32,33,34,35,36,62,63 31 agniaensis araucana 10,14,29,1 argentinica 10, 12, JO cf 93 argo 34,35 catenifera 10,14,29,2 crenulata 33,34 33 elegans elguetai l,12,ii,9.34 32 eufalensis garatei hillehrandii 12,iy, 12,32 luherculata volkheimeri Myophorellinae Myophorigonia Myophorigonia Frenguelliella 30 12,i2, 12,33,34 28,56,57,63 9,19 paucicostala 19 Myophoriidae 10,12,21,27,2 Virgolrigonia 52,53,54 peregrina Ruttlrigonia 54,55 pichimoncolensis Lamherlrigonia 11,14,22,52,52,53,54,5 picunensis plumasensis l,12,i0.8 19 pelerseni 10, 12,30,i7,3 49,54 perezreyesi Pisolrigonia nodulosa schulzi polrerillensis 58 16,36,38,46,49,52,53,59 paucicostala 30 28 mearnsi praescahroidea l,12,i2,8 Parandilrigonia 57 Trigonia Andilrigonia 48 61 47 posadensis Sleinmanella 45 polrerillensis Parandilrigonia 49,54 poulloni Frenguelliella 10,26.2,27 Bulletin 343 94 Scabrotrigonia praescabroidea Myophorella prima 10.12,30.i;.3 11,60 Scaphogonia 31 argo A usirotngonia Promyophorella Scaphorella 10,34 10.1 l,12,16,29,30,i7,32,34 camachoi knmsei 10,12,55.3,36 31 siginoidalis 11,31.55,59,60,61,62 Pterolrtgonia 31 63,64 11,14,55,14,59 aliformis aliformis var attenuata 59 bustamantina 62 62 capricornia coheni 1,14,59.6,60 12,14,67,16,62 coihuecoensis leanzai schuizi Myophorella feruglioi 62 60 sigeli vectiana wmdhauseniana 12,14,62.17 12,58,62 Pterotrigoniinae 1.12,i0,8 64 Auslrolrigonia semicostala 60 59 secunda 59 12,67.9 10,34 12,i4.3 rierafonii 58 sp juv indet 34,35 Scaphotrigonia cubanica stolleyi 10,14,i4,3,35,36 somensis cristata gerthi 10.12,35,3 48 Trigonia Quoiecchia 12,6i,17 sigmoidalis Promyophorella 31 similis Trigonia 21 sobrali pusilla 48 Tngonia Pacilrigonia 12,14.64,17 somensis puslulala 28 Quadralojaworskiella 34,35 Scaphorella splendida Q Quadrajaworskiella 28 28 pustulata Quadra to trigoniinae 56,57 Slemmanella 1,1 Splendilngonia 1,14,40,45,44.45 Slemmanella erycma haupli qmnlucoensis Stcinmanella 1,14,40,'^/ 14,42 Quoiecchia 1.62,63 62,63 aticiae 12,6i 17 sigeli 8.11,12.30,40.41.42.43.45 11.12,40,43,44,7,45 1,14,40,43,44,6,45 herzogi 45 holubi 40 kallcrfeldensis 45 45 maxima neuquensis 11, 4,40,42, 45 posadensis R quintucoensis radixscripta 1,14,40,47.14,42 l,14,49,4i,ll,44 raimondii Andivaugonia raimondii Slemmanella 4,49,4i.l 1,44 10.l4.37,i5.4.39 splendida 12, 40, J 11 slemmanni 12,40,4^.11 rectangidtans laugonia 10,12,i7,2,38 reesidei 1,40,42.13 Iransitoria 12.14,40,47,10 vacaensis 12,40,45,15,16 40 Steinmanellinae sleinmanni Trigonia 57 rierafonii Slemmanella Syrolrigonia Scaphotrigonia 12,i4.3 Rinetrigonia Rutiingonia 1.12.61,62 1,12,54.55.56 agrioensis 12,14,54.16.55.56 kauffmani 12,14,55,15,56 peregrina 54,55 sanchuensis 56 sp juv indet 14,56,9 weaveri 55 Rutitrigoniinae 54.56 1,40,42,13 57,58 slelzneri 20,22 Trigonia slolleyi 60 Plerolrigonia suhsinaia Vaugonia 38 sulcala Venus 19 sylvesleri 64 Pacilrigonia syriaca S Rulitrigonia 56 hiroi brocardoi scabra Trigonia 57 Trigonia Svrolrigonia sanchuensis 60 chilensis 1,12,36,56,57,58 57,58 12,57,16,58 57 Trigoniid Bivalves of Argentina: Leanza 95 21 fraasi 56,57 si mills steinmanni 57,58 sp juv indet gerthi 57,58 slelzneri Uhanotica 56,57 syrlaca 57 Iransitoria var curacoensis 42 ventricosa 61 58 57 paradisensis aff paradisensis T 11,12,23,8 20,22 vyschetzkii 41 wiedmanni 12,24,17 "Trigonia" lapiai 10.26.1,27 FrengiwUietIa 27 coslal ula Trigoniaceae tesselicaudata Amiitngonia eximia 1,12,16,60,9 6,7,18 Tngoniidae Tngoniina 6,7,8,1 1,18,20,46,57 Trigonioida 18 18 ihoracica 60 Plerotrigonia luberculala locaimaana Tngonia 59,60 Myophoreila 30 luberculala topocalmensis 57 Buchotrigonia Myophoreila 10,14,29,1 cf Turbilrigonia transallantica Plerotrigonia 1,14,60,7,61 boudiccae iransiloria 1,1 2,'/0.4 1,42,43,44 10,36 Trigonellina 36 delicata Tngonia 10,1 1,12,17, /9.26,37 aliexpandita 8,12,17,23,24, 10 angidata 29 48 aff angiisia angiistecoslata 12,22,23,24.13,25,27 48 20 arnisoe bajuranasi carinata 8,1 1,14,22,7,23,24 cassiope 24 47 48 48 chacaicoensis aff conocardiiformis consanguinea corderoi 10,14,3,4,5,/9,20,21 10,21 costala 48 crassidens densestriata V 12, 14,40,4/, 10 Sleinmanella Transitrigonia 10,1 2,2/ 3, 23, 27 vacaensis Sleinmanella Vaugonia chunumayensis 38 38 38 lycelti reclangularis 48 Trigonia hugoi 48 manflarum 38 mirandaensis mollesensis 11, 2/ 5, 22 10,14,19,20,2,21 pusilla 34 42 48 48 reesidei 57 scahra 60 48 navis aff nodosa picunensis semicostala Il,14,37,5i.l4,59 52,53,54 volkheimeri Myophoreila Trigonia 10,14,20,5,21 36,37 11,16,46,52,53,54,59 peterseni 1,12,22,6,23 macrorrhyncha 61 veronica vyschetzkii losadai 19 ventricosa 28 47 19 sulcata 44 59 Plerolrigonia Venus hondeana lilerala 36,52,56,57 vecliana gryphitica levyi 36 Vaugoniinae Vaugonia gampsorrhyncha 36,37 vaugonic costation Virgotngonia 49 38 veronica 53 l,12,2i.6,25 10,12,^7.2,38 subslriala 57 10 12, i6 2, 38, 53 goltschei diversicostata eximia var multicostata 12,40,45,15,16 10,i6,37, 38,40,52, 57 exotica dislans fortinensis 53 12,i2, 12,33,34 41 W weaver i 55 Rutilrigonia wiedmanni Trigonia 12,24.17 windhauseniana 12,14,62,17 Plerotrigonia Y Yaadia 42 PREPARATION OF MANUSCRIPTS American Paleontology usually comprises two or more septwo volumes each year The series is a publication outlet for significant, longer paleontological monographs {i.e., more than 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