Jurassic maniraptoriforms (was Re: Protoavis)

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

At 02:19 PM 10/15/97 -0600, LN Jeff wrote:

>> 2.) If dinosaurs are an intermediary step between thecodonts and birds,
>> why did the first birds appear *way* before birdlike features became
>> prevalent in dinosaurs?
>
>      A common, and perhaps most prevalent idea, is that maniraptorians
>(the REALLY bird-like theropods) WERE present in the Jurassic; we just
>haven't found the fossils yet.  

Actually, we DO have their fossils, just not complete ones.  There are
troodontid and dromaeosaurid teeth (or at least teeth which, if found in the
Cretaceous, would unquestionably considered troodontid and dromaeosaurid) as
early as the Bathonian (Middle Jurassic, 169-164 Ma).  These are
contemporaries of Megalosaurus and Cetiosaurus, and predate Archaeopteryx by
ten million years or so.

Why these fossils, in the literature for years, are never mentioned by
Feduccia, Martin, etc. is anybody's guess...

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661