New Hadrosauroids from China

["Alessandro Marisa" <iguanodontia@yahoo.it>]

Hi to all the List-Members for all the Hadrosauroids fun in the new issue of
the journal "Cretaceous Research" there's the follow paper:
Hai-lu You, Zhen-xi Lou, Neil H. Shibin, Lawrence M. Witmer, Zhi-lu Tang and
Feng Tang 2003 The earliest-known duck-billed dinosaur from deposits of late
Early Cretaceous age in northwest China and hadrosaur evolution Vol.24(3)
June 2003 pp:347-355
Here is the abstract:
A new dinosaur of Early Cretaceous age was recently discovered in the Gobi
Desert of northwest China. It is more closely related to Late Cretaceous
hadrosaurids than to Early Cretaceous iguanodontids. It occupies the most
basal position in the phylogeny of all duck-billed dinosaurs, or the
Hadrosauroidea. This early hadrosauroid sheds new light on the origin of the
herbivorous feeding specializations of the Late Cretaceous duck-billed
dinosaurs, and corroborates the view that the Iguanodontidae and the
Hadrosauroidea are monophyletic clades, with the former characterized by an
enlarged maxilla as the main mechanism for mastication, and the latter
diagnosed by a smaller yet more mobile maxilla with an elaborate dental
battery, separated by a diastema from the enlarged premaxilla. Our study
also suggests that the Hadrosauroidea had most likely originated in Asia in
the Early Cretaceous before this clade diversified and spread to other
Laurasian continents during the Late Cretaceous.

By
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Alessandro Marisa
Via Achille Grandi n°18
38068 Rovereto (TN) ITALY
Email: iguanodontia@yahoo.it
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