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New Aristonectes (elasmosaurid plesiosaur) species from Late Cretaceous of Chile



From: Ben Creisler
bcreisler@gmail.com


A paper in the new JVP:


Rodrigo A. Otero, Sergio Soto-Acuña, Frank Robin O'Keefe, José P.
O’Gorman, Wolfgang Stinnesbeck, Mario E. Suárez, David Rubilar-Rogers,
Christian Salazar & Luis Arturo Quinzio-Sinn (2014)
Aristonectes quiriquinensis, sp. nov., a new highly derived
elasmosaurid from the upper Maastrichtian of central Chile.
Journal of Vertebrate Paleontology 34(1): 100-125
DOI:10.1080/0272
http://www.tandfonline.com/doi/full/10.1080/02724634.2013.780953#.Uswm7vRDty8

This paper describes a new species of elasmosaurid plesiosaur,
Aristonectes quiriquinensis, sp. nov., based on a partial skeleton
recovered from upper Maastrichtian beds of the Quiriquina Formation of
central Chile. The material described here consists of two skeletons,
one collected near the village of Cocholgue, and a second juvenile
specimen from Quiriquina Island. Prior to these finds, Aristonectes
was viewed as a monospecific genus, including only the enigmatic
Aristonectes parvidens, the holotype of which consists of an
incomplete skull and incomplete postcranium. Other material referred
to the genus includes an incomplete juvenile skull and other
postcranial material from the upper Maastrichtian of Antarctica, as
well as a partial skull from the Quiriquina Formation of central
Chile. The relationships of Aristonectes have been controversial, with
competing theories assigning the genus to Cryptoclididae,
Elasmosauridae, and Aristonectidae; however, there is a developing
consensus that Aristonectes is a derived elasmosaurid, and this paper
gives strong evidence for this view. Comparison of the specimen here
studied with the holotype of A. parvidens demonstrates that A.
quiriquinensis is a distinct species. The completeness of the adult
skeleton allows the first confident size estimates for adult
Aristonectes. It is a large plesiosaurian with a relatively large
skull with numerous homodont teeth, a moderately long and laterally
compressed neck, and relatively narrow trunk, with slender and
elongate forelimbs. The two specimens are restricted to the upper
Maastrichtian of central Chile, posing questions concerning the
austral circumpolar distribution of different elasmosaurids towards
the end of the Cretaceous.