A plated dinosaur (Ornithischia, Stegosauria) from the Early Cretaceous of Argentina
Publicado por Leonardo Filippi en 11:51
Pereda-Suberbiola, X.,
Galton, P.M., Mallison, H. & Novas, F.
A re-evaluation of several
vertebrae and dermal plates from the Lower Cretaceous (La Amarga Formation, Puesto
Antigual Member, Barremian–lower Aptian)
of Neuquén in Argentina, originally described as a
stegosaurian dinosaur and recently referred to an indeterminate ornithischian,
confirms the former identification. The Neuquén remains have a combination of
features that is only known among stegosaurs: cervical vertebrae with a
proportionally large cross-section of the neural canal, the anterior height and
width of which are half the height of the anterior centrum, as in the cervical
vertebrae of Kentrosaurus,
Dacentrurus and Stegosaurus; prominent lateral depressions on
the cervical centra, as in the presacral vertebrae of Dacentrurus; and cervical dermal
plates that are subtriangular, longer than high and reminiscent of those of Miragaia. Moreover, a small bone here
interpreted to be an anterior supraorbital (=first palpebral) is similar to
that of Stegosaurus
and other stegosaurs in having an elongate form and a dorsal rugose surface.
The remains from Argentina exhibit some differences relative to other
stegosaurs, suggesting that it is potentially a distinct taxon, but their
incompleteness advises against the erection of a new genus and species.
Interestingly, it is the only known skeletal record of Stegosauria in South
America. It provides the second conclusive evidence of the presence of this
clade in the Early Cretaceous of the Gondwanan
landmasses.
Pereda-Suberbiola, X.,
Galton, P.M., Mallison, H. & Novas, F.iFirst article. A plated dinosaur
(Ornithischia, Stegosauria) from the Early Cretaceous of Argentina, South
America: an evaluation. Alcheringa, 1–14. ISSN 0311-5518.
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