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Feathered tyrannosauroids; it's delightful, it's delicious...



...it's Dilong paradoxus!

XU, X., M.A. NORELL, X. KUANG, X. WANG, Q. ZHAO & C. JIA. 2004. Basal
tyrannosauroids from China and evidence for protofeathers in
tyrannosauroids. Nature 431:680-684.

Birds? Pah! Stump-tailed, swelled-headed flying mutants.

Spinosaurids? Crocodile-wannabes with fish on their breath.

Dromaeosaurids? Early K has beens who hung around far after they were
fashionable.

This paper is about REAL theropods.

Namely, Dilong paradoxus (the paradoxical Imperial Dragon), the most
complete basal tyrannosauroid yet known, from the Yixian of Liaoning. Four
specimens are known (one of which may prove to be from a second species),
including a wonderfully complete skull. Adult length estimated at 1.6 m.

Oh, yeah, and there are protofeathers on it.

Dilong's anatomy includes:
Fully D-shaped premaxillary teeth, comparable in size & shape to the (nearly
contemporaneous) Tetori Group tyrannosauroid tooth.
Nasals fused even in juveniles.
Robust, pneumatic lacrimal, and pneumatic jugal.
Reduced prefrontal.
Small but well-defined saggital crest, and well-developed transverse nuchal
crest.
Pneumatic quadrate.
Highly pneumaticized basicranium, with deep basisphenoid recess.
Distal end of scapula greatly expanded relative to shaft.
Three fingered manus, with a very slender metacarpal III.
Extremely large pubic boot.
Non-arctometatarsalian pes.

In other words, not terribly different to what I've been predicting for the
last 15 years (except for the last one, except that for the last four years
or so I've advocated a non-arctometatarsalian ancestry of tyrannosauroids).

Obviously, I'm VERY VERY happy about this little guy.

More later.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
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