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Madagascan Flying Raptor is INDEED a Madagascan Flying Raptor...



Okay, way back in the 1990s the SUNY-Stony Brook team started working the 
Madagascan Late Cretaceous fauna, and came across a funny
little critter. It had a long tail, good old-fashioned sickle claws, elongate 
forelimbs with quill nodes. At the time I (and others)
had nicknamed it the "Madagascan flying raptor."

Later, when the creature was finally published, it was Rahona ostromi (revised 
to Rahonavis). And it was a bird. Probably.

Later came Unenlagia: an Argentine maniraptoran with dromaeosaurid and bird 
features.

And Neuquenraptor: an Argentine maniraptoran with dromaeosaurid and troodontid 
features.

And now the specimen that links all of them together!

Buitreraptor gonzalezorum, the most complete member of Unenlagiinae. Placing it 
in an updated matrix, its pulls the above creatures
together into a clade at the base of Dromaeosauridae (especially if Unenlagia 
and Neuquenraptor are the same taxon, as they
suggest). The remaining (Laurasian) clade contains Microraptorinae (Microraptor 
+ Sinornithosaurus), and a clade of classic
dromaeosaurids, divided into Dromaeosaurinae (Dromaeosaurus, Utahraptor, 
Adasaurus, Saurornitholestes, and Achillobator) and
Velociraptorinae (Velociraptor, Deinonychus, IGM 100/1015).

Like Novas' giant unenlagiine (shown at SVP last year), Buitreraptor has an 
elongate (almost pterodactyloid-like) snout. Its known
from the most complete non-avian theropod found in the Cretaceous of South 
America.

But here's a cool thing. Nearly everyone agrees that Rahonavis was probably a 
flier. It is now a dromaeosaurid. We have flying
dromaeosaurids.

Here's another cool thing. Rahonavis is not at the base of Unenlagiinae 
(Buitreraptor falls there), but it did retain/reverted to
the ancestral eumaniraptoran size. Microraptor is comparably-sized, and while 
not as long armed as Rahonavis likely also had some
aerial ability.  As do basal avialians.

So the Greg Paul hypothesis of flying ancestors of birds and dromaeosaurids 
gets some more support than before. And the possibility
that Velociraptor, Dromaeosaurus, and Deinonychus are all secondarily 
flightless is better than it was based on earlier evidence.

Not to say there aren't complications: the short-armed troodontids, for 
instance. But actually flying dromaeosaurids are looking a
lot more likely...

                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