ELASMOBRANCH FISHES FROM THE CENOMANIAN (LATE CRETACEOUS) OF PATAGONIA, ARGENTINA DISPLAY AN IMPRESSIVE PALAEODIVERSITY IN HIGH LATITUDE DEPOSITS

BEGAT, A.; KRIWET, J.; GOIN F. J.; GELFO J. N.; GOUIRIC-CAVALLI, S.; SCHULTZ, J.A.; MARTIN, T.

Viena

Congreso; 92 Annual Meeting of the Paläontologische Gesellschaft; 2021

The Cretaceous was an important period in the evolution of vertebrates, both on landand in the oceans. This time coincides with the appearance of all modernelasmobranch clades (sharks, rays, skates) that also adapted to new environments(e.g., the open marine realm). Reconfiguration of landmasses resulting from the breakupof Gondwana during the Cretaceous opened new seaways enabling theestablishment of new migration routes and also created wide, shallow epicontinentalseas that are considered to shape diversity patterns of marine organisms positively.Here, we present an elasmobranch fauna from the Cenomanian Mata Amarilla Fm. inthe Austral Basin of Argentine Patagonia (Santa Cruz Province) collected during anArgentine-German field project funded by the National Geographic Society andGerman Research Foundation (DFG). The Mata Amarilla Fm. is characterized by analternating sequence of continental and marine strata that yielded different vertebrateassemblages. So far, at least ten different elasmobranch taxa including hithertounknown species based isolated teeth from marine sediments have been identified.Isolated vertebral centra and dermal denticles of less taxonomic value additionallywere recovered. This unique elasmobranch assemblage is the most diverseassemblage from Cretaceous deposits of South America up to now and contributessignificantly to our still poor knowledge on elasmobranchs in early Late Cretaceoushigh latitudes and especially in South America. The strong taxonomic similarities ofelasmobranch faunas between Patagonia, North America and Europe indicatemigration patterns between the two hemispheres that most likely were enhanced bythe opening of the Atlantic.