Late Cretaceous terrestrial vertebrates from the James Ross Basin, West Antarctica.

REGUERO, M.A.; TAMBUSSI, C.P.; CORIA, R.A.; MARENSSI, S.A.

Antarctic Palaeoenvironmental Evolution

Geological Society of London

Lugar: Londres; Año: 2013;

The fossil record of terrestrial vertebrates from the Late Cretaceous of Antarctica is currently composed by non-avian and avian dinosaurs from the marine sediments of the James Ross Basin, Antarctic Peninsula (West Antarctica). Although two dinosaurian formational assemblages (Late Campanian/ Early Maastrichtian and Late Maastrichtian) are known, the record is still scattered, and evolutionary scenarios are tentative. Ten occurrences of non-avian dinosaurs have been reported from Coniacian to Maastrichtian deposits and five avian dinosaurs have been recorded or described exclusively from the Maastrichtian from the James Ross Basin. Additional non-avian dinosaur evidence from the same area is based upon the occurrence of Early Maastrichtian sauropod? footprints of Snow Hill Island. New discoveries from the Late Campanian/Early Maastrichtian Snow Hill Island Formation at Santa Marta Cove provide relevant data on dinosaur distribution across Gondwana. The Late Campanian/Early Maastrichtian non-avian dinosaurs (ankylosaurs, ornithopods and dromaeosaurid theropods) clades probably attained a near cosmopolitan distribution before the Late Cretaceous, and some aspects of this hallmark ?Gondwanan? fauna may therefore reflect climate-driven provinciality, not vicariant evolution driven by continental fragmentation. Antarctic Late Cretaceous avian dinosaurs are rare and they are restricted to the Maastrichtian and consist in a cariamid?, gaviids, a charadriiform, and, the basal Anseriformes Vegavis. They provide the first strong evidence for a basal radiation of the certain extant birds in the Cretaceous.currently composed by non-avian and avian dinosaurs from the marine sediments of the James Ross Basin, Antarctic Peninsula (West Antarctica). Although two dinosaurian formational assemblages (Late Campanian/ Early Maastrichtian and Late Maastrichtian) are known, the record is still scattered, and evolutionary scenarios are tentative. Ten occurrences of non-avian dinosaurs have been reported from Coniacian to Maastrichtian deposits and five avian dinosaurs have been recorded or described exclusively from the Maastrichtian from the James Ross Basin. Additional non-avian dinosaur evidence from the same area is based upon the occurrence of Early Maastrichtian sauropod? footprints of Snow Hill Island. New discoveries from the Late Campanian/Early Maastrichtian Snow Hill Island Formation at Santa Marta Cove provide relevant data on dinosaur distribution across Gondwana. The Late Campanian/Early Maastrichtian non-avian dinosaurs (ankylosaurs, ornithopods and dromaeosaurid theropods) clades probably attained a near cosmopolitan distribution before the Late Cretaceous, and some aspects of this hallmark ?Gondwanan? fauna may therefore reflect climate-driven provinciality, not vicariant evolution driven by continental fragmentation. Antarctic Late Cretaceous avian dinosaurs are rare and they are restricted to the Maastrichtian and consist in a cariamid?, gaviids, a charadriiform, and, the basal Anseriformes Vegavis. They provide the first strong evidence for a basal radiation of the certain extant birds in the Cretaceous.