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Elasmosaurid plesiosaur from Cretaceous of New Zealand
From: Ben Creisler
A new paper:
Norton Hiller, José P. O'Gorman & Rodrigo A. Otero (2014)
A new elasmosaurid plesiosaur from the lower Maastrichtian of North
Canterbury, New Zealand.
Cretaceous Research 50: 27–37
A postcranial specimen from the lower Maastrichtian levels of the
Conway Formation, Middle Waipara River, North Canterbury, New Zealand
shows clear elasmosaurid affinities, based on the articular faces,
with a ventral notch, of the centra of cervical vertebrae. The ilia
have some distinctive features such as a gracile shaft divided into
two parts by a posterior “knee”, with the distal portion being longer
than the proximal one, and the flattened distal end being slightly
expanded and bearing an ovoid depression. These features differentiate
this specimen from other elasmosaurids from the Weddellian
Biogeographic Province, in which the ilia are known, but these are
considered insufficient grounds on which to erect a new taxon.
However, this specimen demonstrates a potentially greater elasmosaurid
diversity in the lower Maastrichtian of the southern Hemisphere than
previously appreciated. The gastrolith cluster associated with the
bones has sedimentological features similar to those previously
recorded in gastroliths of other elasmosaurids.
We describe a new Late Cretaceous elasmosaurid plesiosaur from New Zealand.
Insufficient material is preserved to warrant erection of a new taxon.
The new form is distinguished principally by the morphology of its ilia.
The specimen adds to the diversity among Weddellian Province plesiosaurs.
Shape parameters of associated gastroliths indicate a possible fluvial source.