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Shaochilong maortuensis: "Chilantaisaurus" no more...



Greetings,

A long-awaited redescription is published.
Brusatte, S., Benson, R., Chure, D., Xu, X., Sullivan, C., & Hone, D.
(2009). The first definitive carcharodontosaurid (Dinosauria: Theropoda)
from Asia and the delayed ascent of tyrannosaurids Naturwissenschaften
DOI: 10.1007/s00114-009-0565-2

Abstract  Little is known about the evolution of large-bodied theropod
dinosaurs during the Early to mid Cretaceous in Asia. Prior to this time,
Asia was home to an endemic fauna of basal tetanurans, whereas terminal
Cretaceous ecosystems were dominated by tyrannosaurids, but the
intervening 60 million years left a sparse fossil record. Here, we
redescribe the enigmatic large-bodied Chilantaisaurus maortuensis from the
Turonian of Inner Mongolia, China. We refer this species to a new genus,
Shaochilong, and analyze its systematic affinities. Although Shaochilong
has previously been allied with several disparate theropod groups
(Megalosauridae, Allosauridae, Tyrannosauroidea, Maniraptora), we find
strong support for a derived carcharodontosaurid placement. As such,
Shaochilong is the first unequivocal Asian member of
Carcharodontosauridae, which was once thought to be restricted to
Gondwana. The discovery of an Asian carcharodontosaurid indicates that
this clade was cosmopolitan in the Early to mid Cretaceous and that Asian
large-bodied theropod faunas were no longer endemic at this time. It may
also suggest that the ascent of tyrannosaurids into the large-bodied
dinosaurian predator niche was a late event that occurred towards the end
of the Cretaceous, between the Turonian and the Campanian.

Shaochilong translates as "Shark tooth dragon", and thus is basically a
Chinese translation of Carcharodontosaurus!

Discussion at:
http://archosaurmusings.wordpress.com/2009/06/04/guest-post-shark-toothed-theropods-in-asia-introducing-shaochilong/

A taxonomic footnote: Dan Chure proposed a new name for this critter in
his dissertation and the long-in-limbo monograph. I was glad to see that
he is on this paper, as I would hate to have seen him scooped. The name he
proposed was quite different (it floats around here and there on the
internet), and is thus now potentially available for a different dinosaur.

Another taxonomic footnote: the authors do point out in the Supplementary
data that there does exist a chance that Shaochilong may wind up
synonymous with Chilantaisaurus.

Additional footnote: With the possible ceratopsid (and certainly
ceratopsoid) Turanoceratops in coeval deposits in Uzbekistan, there now
exists a possibility that would have seemed unreasonable just a few years
ago:

An allosaur fighting a horned dinosaur in Asia.

Go figure...

Congrats to the whole team!

-- 
Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661

Faculty Director, Earth, Life & Time Program, College Park Scholars
http://www.geol.umd.edu/~jmerck/eltsite/
Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA