The recovery of material of a small theropod from the Early Maastrichtian, Cape Lamb Member of the Snow
Hill Island Formation is an unusual occurrence from primarily marine sediments. The pedal morphology of the
specimen that includes a Metatarsal II with a lateral expansion caudal to Metatarsal III, a third metatarsal that is
proximally narrow and distally wide, a Metatarsal III with a distal end that is incipiently ginglymoidal and a second
pedal digit with sickle-like ungual are all diagnostic of a theropod that belongs to the family of predatory dinosaurs, the
Dromaeosauridae. Yet this Antarctic dromaeosaur retains plesiomorphic features in its ankle and foot morphology. As
new dromaeosaur species are being recovered from the mid-Cretaceous of South America and the retention of primitive
characters in the Antarctic dromaeosaur, a new biogeographic hypothesis on dromaeosaur distribution has been
generated. Gondwanan dromaeosaurs are not North America immigrants into South America and Antarctica; rather
they are the relicts of a cosmopolitan dromaeosaur distribution, which has been separated by the vicariant break up of
Pangea and created an endemic clade of dromaeosaurs in Gondwana.
Study Area
Additional publication details
Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
A dromaeosaur from the Maastrichtian of James Ross Island and the Late Cretaceous Antarctic dinosaur fauna
Series title:
Open-File Report
Series number:
2007-1047-SRP-083
DOI:
10.3133/ofr20071047SRP083
Year Published:
2007
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Description:
4 p.
Larger Work Type:
Report
Larger Work Subtype:
USGS Numbered Series
Larger Work Title:
Antarctica: A Keystone in a Changing World--Online Proceedings for the Tenth International Symposium on Antarctic Earth Sciences. Santa Barbara, California, U.S.A.--August 26 to September 1, 2007
