Vertebrados marinos del Cenozoico de Chubut

MARIANA VIGLINO; MÓNICA R. BUONO; CAROLINA ACOSTA HOSPITALECHE; ALBERTO CIONE; JOSE CUITIÑO; CARLOS MAXIMILIANO GAETÁN; JULIANA STERLI; FLORENCIA PAOLUCCI

Geología y recursos naturales de la provincia de Chubut. XXI Congreso Geológico argentino

Asociación Geológica Argentina

Año: 2021; p. 1005 - 1028

During the Cenozoic in Patagonia, four marine transgressive-regressive cycles occurred, three of which are recorded in the Chubut Province. The geological record of these events can be studied in the Salamanca, Lefipán, Foyel, Chenque, Gaiman and Puerto Madryn Formations, comprising part of the Paleocene and Miocene epochs. Here, we outline the fossil marine vertebrate record of these units, which includes birds, mammals, turtles and fishes. Some of these fossils were already studied in the 19th century, whilst another important contribution arises from the work of young researchers today. Among fishes, elasmobranch teeth are the most abundant, although some finely preserved osteichthyes are reported. For turtles, some Pan-Dermochelyidae specimens are known, and here we report Pan-Cheloniidae records for the first time in the Cenozoic of Chubut. Then, fossil record of birds consists mainly of penguins, and some ducks. Finally, cetaceans include, for example, basal odontocetes lineages and the oldest balaenid. During the Paleogene, only fishes and a single bird are recorded. In turn, there is a marked increase in fossil marine vertebrates diversity and abundance by the early Miocene, followed by a less diverse but more modern species by the late Miocene. This faunistic turnover might be related to paleoenvironmental (such as the occurrence of the Antarctic Circumpolar Current) or taphonomic variations. Future comprehensive paleobiological and paleoecological studies of these fossils in a stratigraphic context are needed in order to better understand diversity patterns and conduct paleoenvironmental reconstructions. These results will thus allow a better characterization of the Patagonian sea during the Cenozoic.