Effigia monograph in the Bulletin of the AMNH

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

Sterling's been very busy lately...:
Nesbitt, S. 2007. THE ANATOMY OF EFFIGIA OKEEFFEAE (ARCHOSAURIA, SUCHIA), 
THEROPOD-LIKE CONVERGENCE, AND THE DISTRIBUTION OF RELATED
TAXA. Bulletin of the American Museum of Natural History 302. 84 pp.

Abstract

Effigia okeeffeae is named based on a well-preserved nearly complete skeleton 
from the Upper Triassic (?Rhaetian) ?siltstone member?
at Ghost Ranch, northern New Mexico. The skull is described and compared to 
other suchian and basal archosaurs. The maxilla and
premaxilla are edentulous, and a rhamphotheca was possibly present in life.

Effigia conclusively indicates that the skull of Shuvosaurus and the postcrania 
of ?Chatterjeea? belong to the same taxon.
Furthermore, the close relationship between Shuvosaurus and Effigia indicates 
that both taxa are nested within the suchian clade and
not within Ornithomimisauria. However, the similarity in features in the skull 
and postcrania of Effigia and ornithomimids suggests
extreme convergence occurred between the two clades.

A clade containing Arizonasaurus, Bromsgroveia, Poposaurus, Sillosuchus, 
Shuvosaurus, and Effigia is suggested based solely on
shared derived character states. Additionally, a clade (Clade Y) containing 
Sillosuchus, Shuvosaurus, and Effigia is well supported
by further derived character states. The distribution and temporal pattern of 
members of Group Y suggest that members of Group Y are
present in the early Middle Triassic through the Latest Triassic of North 
America, and one member of the clade, Sillosuchus, was
present in South America.

Before anyone asks, the PDF is 12.1 Mb, far more than my mail accounts will 
allow me to send...

                Thomas R. Holtz, Jr.
        Senior Lecturer, Vertebrate Paleontology
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

http://www.geol.umd.edu/~tholtz/
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796