[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

new paper and new sauropod genus



Jeffrey A. Wilson & Paul Upchurch. 2003. A revision of Titanosaurus Lydekker 
(Dinosauria ? Sauropoda), the first dinosaur genus with a ?Gondwanan? 
distribution. Journal of Systematic Palaentology, 1(3), 125?160 (Issued 6 
November 2003)


SYNOPSIS Titanosaurs represent approximately one-third of sauropod diversity 
and were geographically widespread throughout the Cretaceous, especially on 
southern continents. Titanosaurs evolved numerous appendicular synapomorphies 
that account for their specialised ?wide-gauge? limb posture, which can be 
recognised in their trackways. The macronarian origin of titanosaurs is only 
recently agreed upon and aspects of their inter-relationships remain poorly 
understood. Titanosauria is named for the poorly known genus Titanosaurus, 
whichwas coined by Lydekker in 1877 on the basis of a partial femur and two 
incomplete caudal vertebrae. Fourteen species have since been referred to 
Titanosaurus, which distribute the genus across Argentina, Europe, Madagascar, 
India and Laos, and throughout 60million years of the Cretaceous. Despite its 
centrality to titanosaur systematics and biogeography, the genus Titanosaurus 
has never been revised. A re-evaluation of all Titanosaurus species recognises 
as diagnostic only ?ve. The type species T. indicus is invalid because it is 
based on ?obsolescent? characters ? once diagnostic features that have gained 
abroader taxonomic distributionover time. Consequently, the genus Titanosaurus 
and its co-ordinated rank-taxa (e.g. Titanosaurinae, Titanosauridae, 
Titanosauroidea) must be abandoned. The unranked taxon Titanosauria, however, 
remains valid. A new phylogenetic taxonomy is proposed for Titanosauria that 
utilises nodes that have been judged stable by themost recent cladistic 
analyses. The early appearance of titanosaur ichnofossils (Middle Jurassic) and 
body fossils (Late Jurassic) precludes a vicariant origin for the group, but 
such a pattern cannot yet be ruled out for lower-level taxa within 
Titanosauria.

new genus: Isisaurus Wilson & Upchurch 2003
type species: Isisaurus colberti (Jain & Bandyopadhay, 1997)
Occurrence: Lameta Formation (Maastrichtian), India


-------------------------
Jose Ignacio Ruiz-Omeñaca
Departamento de Ciencias de la Tierra
Area de Paleontologia
Universidad de Zaragoza
E-50009 ZARAGOZA

tel: (+34) 976 761000 ext. 3160
fax: (+34) 976 761106
e-mail: jigruiz@unizar.es
-------------------------