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Elasmosaurid plesiosaur skeleton from Chile

Ben Creisler

A new paper:

Rodrigo A. Otero, Sergio Soto-Acuña, Alexander O. Vargas & David
Rubilar-Rogers (2014)
A new postcranial skeleton of an elasmosaurid plesiosaur from the
Upper Cretaceous of central Chile and reassessment of Cimoliasaurus
andium Deecke.
Cretaceous Research 50: 318–331
DOI: 10.1016/j.cretres.2014.05.008

A long-necked elasmosaurid plesiosaur from southern South America.
A regionally scarce kind of plesiosaur along the southeastern Pacific.
Addition to the plesiosaur diversity along the Southern Hemisphere.


We describe a new specimen of an elasmosaurid plesiosaur from the
upper Maastrichtian of central Chile. The specimen includes a
relatively complete dorso-caudal series, a few cervical vertebrae, and
a fragmentary pelvic girdle. The specimen is identified as a sub-adult
non-artistonectine elasmosaurid (Sauropterygia, Plesiosauria) based on
graphic bivariate analysis of the cervical vertebral proportions. The
caudal vertebrae have distinctive features such as neural arches that
are recurved cranially, with pedicels overlapping the dorso-posterior
surface of the immediately anterior centrum, and terminal centra with
two pairs of deep dorsal articulations for the neural arches. These
unusual features are present in several late Maastrichtian adult
specimens from the Quiriquina Formation of central Chile, and have
been included within the hypodigm of the historic taxon Cimoliasaurus
andium Deecke (nomen dubium). The specimen studied here likely
represents the same taxon or a closely related form, showing slight
differences in both size and ontogenetic stage. The preserved elements
of this new skeleton afford comparison with several other late
Maastrichtian specimens from Chile that were previously, albeit
tentatively, referred to “C. andium”. The similarity of these
specimens suggests that the late Maastrichtian elasmosaurid diversity
of central Chile (excluding aristonectines) may be represented by taxa
with low morphological disparity, or by a single taxon.