INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
Triassic spinicaudatan fauna from the Cerro de Las Cabras Formation (Cuyo Basin), Mendoza Province (Argentina): description of new species and revision of previous records.
VAZ TASSI, L.; ZAVATTIERI, A.M.; GALLEGO, O.F.
ASOCIACION PALEONTOLOGICA ARGENTINA
Lugar: Buenos Aires; Año: 2015 vol. 52 p. 241 - 264
This is a systematic study of the Spinicaudata fauna of the Cerro de Las Cabras Formation (Middle Triassic), north of Cerro Bayo, in the classical Potrerillos area, Precordillera of Mendoza, Cuyo Basin, Argentina. Two new species are described: Estheriellites zavattieriae sp. nov. and Euestheria menendezi sp. nov.. The diagnosis of the genus and species of Challaolimnadiopsis mendozaensis Shen and Gallego, is emended; and Euestheria martinsnetoi Gallego et al., previously described for the Río Mendoza Formation is now considered as coming from the Cerro de Las Cabras strata. The studied section consists mainly of fine-grained tuffaceous sandstones and interbedded mudstones interpreted as playa lake, ephemeral rivers and/or streams developed in the floodplain. Ephemeral to shallow lacustrine environments are characterized by interbedded siltstones and nodular-mottled and stromatolitic limestones with sub-aerial exposure, evidenced by desiccation cracks and roots (casts and molds), indicating incipient soil development in depressed and flood-prone areas under semi-arid conditions with marked seasonality. Spinicaudatans probably inhabited lacustrine shorelines and small ponds in the floodplain where plant remains (arthrophyte) and rare fish scales were also recorded. The profuse presence of pyroclastic deposits along the sequence indicates considerable explosive volcanic activity coeval with sedimentation. Based on previous lithostratigraphical, paleontological and chronological data, the age of the studied deposits was constrained to Middle Triassic (equivalent to Late Anisian?Late Ladinian of marine sequences) and therefore the E. zavattieriae-E. martinsnetoi Faunal Association is considered as a marker for such age range.