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Dinheirosaurus and European diplodocoids

From: Ben Creisler

A new online paper:

Philip D. Mannion, Paul Upchurch, Octávio Mateus, Rosie N. Barnes & Marc E.
H. Jones (2011)
New information on the anatomy and systematic position of Dinheirosaurus
lourinhanensis (Sauropoda: Diplodocoidea) from the Late Jurassic of
Portugal, with a review of European diplodocoids.
Journal of Systematic Palaeontology (advance online publication)

Although diplodocoid sauropods from Africa and the Americas are well known,
their European record remains largely neglected. Here we redescribe
Dinheirosaurus lourinhanensis from the Late Jurassic of Portugal. The
holotype comprises two posterior cervical vertebrae, the dorsal series and
a caudal centrum. Redescription demonstrates its validity on the basis of
three autapomorphies: (1) posteriorly restricted ventral keel on posterior
cervical vertebrae; (2) three small subcircular fossae posterior to the
lateral coel on posterior cervical neural spines; (3) accessory lamina
linking the hyposphene with base of the posterior centrodiapophyseal lamina
in middle-posterior dorsal vertebrae. Phylogenetic analysis places
Dinheirosaurus as the sister taxon to Supersaurus, and this clade forms the
sister taxon to other diplodocines. However, this position should be
treated with caution as Dinheirosaurus displays several plesiomorphic
features absent in other diplodocids (including unbifurcated presacral
neural spines, and dorsolaterally projecting diapophyses on dorsal
vertebrae) and only four additional steps are required to place
Dinheirosaurus outside of Flagellicaudata. We identify Amazonsaurus as the
basal-most rebbachisaurid and recover Zapalasaurus outside of the South
American Limaysaurinae, suggesting the biogeographic history of
rebbachisaurids is more complex than previously proposed. Review of the
European diplodocoid record reveals evidence for the earliest known
diplodocid, as well as additional diplodocid remains from the Late Jurassic
of Spain. A Portuguese specimen, previously referred to Dinheirosaurus,
displays strong similarities to Apatosaurus from the contemporaneous
Morrison Formation of North America, indicating the presence of a second
Late Jurassic Portuguese diplodocid taxon. Along with Dinheirosaurus, these
Portuguese remains provide further evidence for a Late Jurassic
palaeobiogeographic connection between Europe and North America. No
dicraeosaurids are currently known from Europe, but rebbachisaurids are
present in the Early Cretaceous, with weak evidence for the earliest known
representative from the Late Jurassic of Spain; however, more complete
material is required to recognize early members of this clade.

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