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Elasmosaurid plesiosaurs from Late Cretaceous of Antarctica



From: Ben Creisler
bcreisler@gmail.com


A new online paper:

Rodrigo A. Otero,  Sergio Soto-Acuña, Alexander O. Vargas, David
Rubilar-Rogers, Roberto E. Yury-Yañez & Carolina S. Gutstein (2013)
Additions to the diversity of elasmosaurid plesiosaurs from the Upper
Cretaceous of Antarctica.
Gondwana Research (advance online publication)
http://dx.doi.org/10.1016/j.gr.2013.07.016,
http://www.sciencedirect.com/science/article/pii/S1342937X1300244X


Three specimens of elasmosaurid plesiosaurs (Sauropterygia,
Plesiosauroidea) from Upper Cretaceous beds of Antarctica are
described here. These include postcranial remains of a single adult
individual recovered from late Maastrichtian beds of Marambio (=
Seymour) Island, possessing distinctive cervical vertebrae with the
transverse section of the centra having a triangular outline, a
vertical groove on the rostral and caudal edge of the neural spines,
and a deep articulation over the neural arch for the following
postzygapohysis, while the scapula shows an unusually large and
anteriorly recurved dorsal process. This combination of features is
not known to occur in any adult, postcranial elasmosaurid genus
recovered to date in the Upper Cretaceous of the Weddellian
Biogeographic Province and could represent a new form. Additional
specimens from James Ross Island comprise the first record of an
Aristonectinae (Plesiosauria, Elasmosauridae) in late Campanian beds,
being the oldest known record of this sub-family. Finally, a third
specimen from the same age and locality reveals the presence of
very-long necked elasmosaurids with affinities to typical
representatives from the Upper Cretaceous of the Northern Hemisphere.
These findings add to the known diversity of Upper Cretaceous
elasmosaurids in high latitudes of the Southern Hemisphere.