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Ichthyovenator, new spinosaurid from Early Cretaceous of Laos



From: Ben Creisler
bcreisler@gmail.com

A new online paper:

Ronan Allain, Tiengkham Xaisanavong, Philippe Richir and Bounsou
Khentavong (2012)
The first definitive Asian spinosaurid (Dinosauria: Theropoda) from
the Early Cretaceous of Laos.
Naturwissenschaften (advance online publication)
2012, DOI: 10.1007/s00114-012-0911-7
http://www.springerlink.com/content/r5x213648388tt23/


Spinosaurids are among the largest and most specialized carnivorous
dinosaurs. The morphology of their crocodile-like skull, stomach
contents, and oxygen isotopic composition of the bones suggest they
had a predominantly piscivorous diet. Even if close relationships
between spinosaurids and Middle Jurassic megalosaurs seem well
established, very little is known about the transition from a
generalized large basal tetanuran to the specialized morphology of
spinosaurids. Spinosaurid remains were previously known from the Early
to Late Cretaceous of North Africa, Europe, and South America. Here,
we report the discovery of a new spinosaurid theropod from the late
Early Cretaceous Savannakhet Basin in Laos, which is distinguished by
an autapomorphic sinusoidal dorsosacral sail. This new taxon,
Ichthyovenator laosensis gen. et sp. nov., includes well-preserved and
partially articulated postcranial remains. Although possible
spinosaurid teeth have been reported from various Early Cretaceous
localities in Asia, the new taxon I. laosensis is the first definite
record of Spinosauridae from Asia. Cladistic analysis identifies
Ichthyovenator as a member of the sub-clade Baryonychinae and suggests
a widespread distribution of this clade at the end of the Early
Cretaceous. Chilantaisaurus tashouikensis from the Cretaceous of Inner
Mongolia, and an ungual phalanx from the Upper Jurassic of Colorado
are also referred to spinosaurids, extending both the stratigraphical
and geographical range of this clade.