Megaraptor: details

["Thomas R. Holtz, Jr." <th81@umail.umd.edu>]

To answer some of the recent questions:

Yes, there really is a dinosaur called _Megaraptor_.  The full name is
_Megaraptor namunhuaiquii_.  It is from the Rio Neuquen Formation of
Argentina (Late Cretaceous), the same formation that contains the primitive
bird _Unenlagia_ and the more advanced _Patagonykus_, as well as an as-yet
unofficially named troodontid-like form.

_Megaraptor_ was described by Argentine paleontologist Fernando Novas in
1998, in the following paper:
Novas, F.E. 1998.  _Megaraptor namunhuaiquii_, gen. et sp. nov., a
large-clawed, Late Cretaceous theropod from Patagonia.  Journal of
Vertebrate Paleontology 18:4-9.

It is only known from very, very, very few parts of the body: a right ulna
(forearm bone), one left finger bone (phalanx I-1), the lower part of right
metatarsal III (long bone of the foot), and the big claw from the second toe
of the right foot.  That is it: that is the sum total of the material known
when first described.  If Fernando or others have recovered more, they
haven't reported it.

What is _Megaraptor_?  It's a theropod, and most likely a coelurosaur.  It
probably ISN'T a typical dromaeosaurid (the family of "raptors").  It could
be a close relative of the dromaeosaurids, or another group entirely that
indepedently evolved the sickle claw.  Hadn't heard anyone had suggested it
as a therizinosaur...

How big is it?  Really, REALLY hard to say: anyone who gives you actual
height or length measurements is extrapolating based on comparisons to other
forms.  Novas gives a rought estimate of about 8 m (26 feet or so) long.
It's claw is immense, though: 54% bigger than that of _Utahraptor_.

That's just about it.  Such is life in paleontology: often, the most
interesting fossils are the most fragmentary.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:tholtz@geol.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661