Sarahsaurus - new(ish) sauropodomorph from Arizona

[Tim Williams <tijawi@gmail.com>]

A new sauropodomorph _Sarahsaurus aurifontanalis_ is described, but I
don't know if the publication date will be 2010 or 2011.  The name
references Sarah Butler, and Gold Spring, Arizona.  Almost a complete
skeleton is known, as well as a skull that was previously referred to
_Massospondylus_.


Rowe, T.B., Sues, H.-D., and Reisz, R.R. Dispersal and diversity in
the earliest North American sauropodomorph dinosaurs, with a
description of a new taxon.  Proc. R. Soc. B
doi:10.1098/rspb.2010.1867  (Published online)


Abstract: "Sauropodomorph dinosaurs originated in the Southern
Hemisphere in the Middle or Late Triassic and
are commonly portrayed as spreading rapidly to all corners of Pangaea
as part of a uniform Late Triassic
to Early Jurassic cosmopolitan dinosaur fauna.  Under this model,
dispersal allegedly inhibited dinosaurian
diversification, while vicariance and local extinction enhanced it.
However, apomorphy-based
analyses of the known fossil record indicate that sauropodomorphs were
absent in North America until
the Early Jurassic, reframing the temporal context of their arrival.
We describe a new taxon from the
Kayenta Formation of Arizona that comprises the third diagnosable
sauropodomorph from the Early
Jurassic of North America.  We analysed its relationships to test
whether sauropodomorphs reached
North America in a single sweepstakes event or in separate dispersals.
 Our finding of separate arrivals
by all three taxa suggests dispersal as a chief factor in dinosaurian
diversification during at least the
early Mesozoic.  It questions whether a ‘cosmopolitan’ dinosaur fauna
ever existed, and corroborates
that vicariance, extinction and dispersal did not operate uniformly in
time or under uniform conditions
during the Mesozoic.  Their relative importance is best measured in
narrow time slices and circumscribed
geographical regions."


An on-line National Geographic article mentions that _Sarahsaurus_ had
powerful hands and was possibly omnivorous - aspects of its biology
that are not addressed in the paper.

http://news.nationalgeographic.com/news/2010/10/101006-new-dinosaur-north-america-science/



Cheers

Tim