NEW LATE MIOCENE BIRD ASSEMBLAGE FROM SAN JUAN PROVINCE,ARGENTINA

GERARDO ÁLVAREZ HERRERA; VICTOR H. CONTRERAS; FEDERICO AGNOLÍN; SEBASTIÁN ROZADILLA; RODRIGO L. TOMASSINI

La Rioja

Jornada; XXXVI Jornadas Argentinas de Paleontología de Vertebrados; 2023

The Neogene avifauna record from San Juan Province is poorly known. The aim of the present contribution is the description of a new diverse Late Miocene assemblage from Las Flores Formation, cropping out in the area of Puchuzum in the Calingasta Valley (San Juan Province, Argentina). Bearing levels represent fluvial systems of meandering rivers and wide flooding plains, which are associated to deposits of an ephemeral lake (“Puchuzum lake”), exposed to seasonal droughts due periods with low pluviosity or high aridity. The assemblage includes more than thirty disarticulated and isolated postcranial remains and is composed of a new genus of tadornine anatid, a new genus of basal podicipedid, a new species of the extinct palaelodid Palaelodus, and indeterminate rallids, ardeids, and recurvirostrids. The fossils here reported constitute a typical waterbird assemblage, in agreement with the paleoenvironmental interpretation of the bearing levels, and include the oldest record for ardeids, recurvirostrids, and podicipedids in South America. This assemblage greatly increases the avian record from the Miocene of western Argentina.