Before and after the K/Pg extinction in West Antarctica: New marine fish records from Marambio (Seymour) Island

CIONE, ALBERTO L.; SANTILLANA, SERGIO; GOUIRIC-CAVALLI, SOLEDAD; ACOSTA HOSPITALECHE, CAROLINA; GELFO, JAVIER N.; LÓPEZ, GUILLERMO M.; REGUERO, MARCELO

CRETACEOUS RESEARCH (PRINT)

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2018 vol. 85 p. 250 - 265

0195-6671

An ichthyofauna recovered from the Lopez de Bertodano Formation at Units 9 (uppermost Maastrichtian)and 10 (lowermost Danian) and the Sobral Formation (Danian), in Marambio (Seymour) Island in theJames Ross Basin is described and analyzed herein. A review of previously described taxa based on thenew material and several new fish records for the Lopez de Bertodano Formation is provided, includingthe youngest record of Enchodus and the first Cretaceous evidence of Pachycormiformes.We also identifythe first Paleocene fishes for the continent. The new information and the reinterpretation of previousCretaceous records show that there was no decline in fish diversity until the CretaceousePaleogene (K/Pg) boundary in the area and extinction event appears to have been rapid. Finally, we find that thedistribution of some chondrichthyans and teleosts in the James Ross Basin appears to be climaticallydetermined.