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Sciurimimus, the fuzzy megalosaur



This just in:

Oliver W. M. Rauhut, Christian Foth, Helmut Tischlinger, and Mark A. Norell
Exceptionally preserved juvenile megalosauroid theropod dinosaur with
filamentous integument from the Late Jurassic of Germany
PNAS 2012 : 1203238109v1-201203238.

Abstract

Recent discoveries in Asia have greatly increased our understanding of the
evolution of dinosaurs? integumentary structures, revealing a previously
unexpected diversity of ?protofeathers? and feathers. However, all
theropod dinosaurs with preserved feathers reported so far are
coelurosaurs. Evidence for filaments or feathers in noncoelurosaurian
theropods is circumstantial and debated. Here we report an exceptionally
preserved skeleton of a juvenile megalosauroid, Sciurumimus albersdoerferi
n. gen., n. sp., from the Late Jurassic of Germany, which preserves a
filamentous plumage at the tail base and on parts of the body. These
structures are identical to the type 1 feathers that have been reported in
some ornithischians, the basal tyrannosaur Dilong, the basal
therizinosauroid Beipiaosaurus, and, probably, in the basal coelurosaur
Sinosauropteryx. Sciurumimus albersdoerferi represents the
phylogenetically most basal theropod that preserves direct evidence for
feathers and helps close the gap between feathers reported in
coelurosaurian theropods and filaments in ornithischian dinosaurs, further
supporting the homology of these structures. The specimen of Sciurumimus
is the most complete megalosauroid yet discovered and helps clarify
significant anatomical details of this important basal theropod clade,
such as the complete absence of the fourth digit of the manus. The
dentition of this probably early-posthatchling individual is markedly
similar to that of basal coelurosaurian theropods, indicating that
coelurosaur occurrences based on isolated teeth should be used with
caution.


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, 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