Promising future: a new mammal-bearing microvertebrate locality from the Cañadón Asfalto formation (Jurassic; Chubut, Argentina)

TURAZZINI GUILLERMO F.; APPELLA-GUISCAFRE LUCAS S.; LIRES A. I.; GARBEROGLIO F.; CANESSA LEANDRO A.; GÓMEZ R. O.; ROUGIER GUILLERMO W.

General Roca

Congreso; XI Congreso de la Asociación Paleontológica Argentina; 2016

Asociación Paleontológica Argentina

The Cañadón Asfalto Formation is one of the richest fossiliferous continental units of Early?Middle Jurassic age from former Gondwanan landmasses. Notably among the various fossil sites is ?Queso Rallado?, the single locality yielding mammals as well as a diverse sample of micro to mid-size vertebrates. The skeletal remains of mammals and relatives are the only known for the Jurassic South America and potentially the oldest record for Mammalia worldwide. Queso Rallado is situated 5.5 km northwest of the Cerro Cóndor village (Chubut Province, Argentina), and has yielded in addition to mammals, turtles, dinosaurs, pterosaurs, rhynchocephalians, crocodyliforms, anurans and fishes. This locality has been exploited annually for the last fifteen years and a point has been reached where future extraction of rocks is logistically very challenging. In this context, we gladly report on a new fossiliferous site, "Canela", where in addition to several frog, fish, turtle, and archosaur remains, a single well-preserved mandible of the australosphenidan Henosferus sp. has been recovered. The new locality is situated 800 m south of "Queso Rallado" and the fossil-bearing level consists of a lenticular 0.5 m-thick deposit of laminated calcareous and tuffaceous rocks. The composition, geometry and stratigraphic position of Canela and Queseo Rallado suggest that their sediments, representing small and shallow lacustrine bodies, belong to the samedepositional system and are of a similar age. It is in fact possible the localities are local expressions of the same body of water.