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A new crustacean clam shrimp (Spinicaudata: Eosestheriidae) from the Upper Triassic of Argentina and its importance for ‘conchostracan’ taxonomy

2010; Taylor & Francis; Volume: 34; Issue: 2 Linguagem: Inglês

10.1080/03115510903546152

1752-0754

Oscar F. Gallego,

Coral and Marine Ecosystems Studies

Abstract A new species of a fossil crustacean clam shrimp (Spinicaudata: Eosestheriidae) Menucoestheria wichmanni is described from the lower Upper Triassic Vera Formation (Los Menucos Complex) in Río Negro Province, southern Argentina. This discovery represents the first record of this family in the Triassic of Argentina and the southernmost record of South American Triassic 'conchostracans' (Spinicaudata). The new species shows close affinities with Middle Jurassic faunas from Antarctica and offers important data on the taxonomy (notably the use of ornamentation characters), palaeobiogeography (as South America hosts the oldest-known fossils of this family) and evolution of the Gondwanan faunas. Other South American eosestheriid species are tentatively recognized. Menucoestheria is hypothesized to be the ancestral form of the Triassic–Jurassic Gondwanan eosestheriids. Relationships between European and Gondwanan eosestheriids remain unresolved. Key words: SpinicaudataEosestheriidaetaxonomyevolutionbiogeographyTriassicVera FormationArgentina Acknowledgements I especially thank the journal reviewers, Ewa Olempska and Gang Li for their helpful comments on the manuscript. I thank Claudio Iglesias (Argentina) for sending the material for study and for helpful comments on the sedimentological aspects of the Vera Formation, Shen Yan-Bin (Nanjing Institute of Geology and Palaeontology, Academia Sinica, China), Tom DeVries (Burton, USA), Sven Nielsen (GeoForschungsZentrum Potsdam, Germany), Gregory Edgecombe (The Natural History Museum, London) and Lara Vaz Tassi (CECOAL-CONICET and UNNE-ANPCyT) who revised the manuscript and the English language. I also thank Heinz Kozur (Budapest, Hungary) for his permanent collaboration in our research. Thanks also to Nadia S. Domnanovich (Laboratorio de Paleontología de Vertebrados—Universidad de Buenos Aires) and Nora Cabaleri (Instituto de Geocronología y Geología Isotópica—UBA—CONICET) for their suggestions on the tetrapod assemblage and sedimentological terms, respectively. Cristina Salgado and Carolina Peichotto (from the SEM staff—Secretaría General de Ciencia y Técnica—Universidad Nacional del Nordeste, Corrientes, Argentina) are thanked for their assistance. Thanks also go to Mr Gustavo Barrios (Corrientes, Argentina) for his work with the digital figures. This study was partially supported by the Consejo Nacional de Investigaciones Científicas y Técnicas CONICET-Argentina (Grant PIP-5581), the Secretaría General de Ciencia y Técnica, Universidad Nacional del Nordeste (Grant PI-64/04 and 075-2007) and the Agencia Nacional de Promoción Científica y Tecnológica (Grant 0226/07).