Late Cretaceous Mosasaurs (Squamata: Mosasauroidea) from the Maastrichtian of Marambio (=Seymour) Island, Antarctica

REGUERO, M.; BARRIENTOS LARA,JAIR; FERNÁNDEZ, MARTA; ALVARADO ORTEGA, JESÚS; TALEVI, M.; O'GORMAN, J.; IGLESIAS, A.; MOLY, J.J.

Simposio; XII International Symposium on Antarctic Earth Science (ISAES 2015); 2015

Mosasaurs were highly specialized squamates that invaded the marine realm during the Late Cretaceous.Their fossil records indicate that, after the first appearance about 98 Ma ago, they quickly diversified andradiated into marine environments all over the world. Explanations for their extinction comprise twohypotheses. One invokes a gradualist scenario, in which a widespread regression of epicontinental seasduring the Maastrichtian produced a reduction of marine habitats and the decline of mosasaur well beforethe K/Pg boundary; while the other correlates mosasaur extinction with the big crisis at the K/Pg boundarytriggered by a bolide impact. A catastrophic drop in planktonic productivity at the K/Pg would affectspecies up the food chain, including mosasaurs. If mosasaurs, as well as other apical predators such asplesiosaurs, were gradually driven into extinction it is expected that there would be a reduction inabundance, diversity, and biogeographic range of their fossil records well before the K/Pg. Recentresearches carried out in Angola, as well as review of other K/Pg boundary sections containingmosasaurs, suggest a possible diversity decline prior to their extinction. Nevertheless, the collapse ofmarine productivity at the end of the Cretaceous could have been responsible for their total extinction