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Dromies, birds - and Protoavis question





How can time not count? You can't be older than your ancestors? People say that birds descended from dromeosaurs...but there are 0 dromeosaurs known from before the late Jurassic! Time is very important.

Just a clarification. I don't think anyone is saying that birds evolved directly FROM dromaeosaurids, any more than anthropologists claim that humans evolved from chimpanzees. Birds and dromaeosaurids share a close common ancestor. Much of the debate centers on just how close the Dromaeosauridae and Aves (or Avialae) are in theropod phylogeny. Do dromaeosaurids and troodontids comprise a monophyletic sister taxon (Deinonychosauria) to the Aves? Is _Rahonavis_ positioned between dromaeosaurids and Aves, or is it more derived than _Archaeopteryx_? That sort of thing.


As for pre-Late Jurassic dromaeosaurids. This was discussed fairly recently, and there are indeed a lot of dromaeosaurid-like teeth from pre-Tithonian strata. I think these need to be attached to skeletal elements to be more certain of their affinities. To me, the _Ozraptor_ tibia (Middle Jurassic, Australia) looks somewhat dromaeosaurid, and _Nuthetes_ (Middle Jurassic, England) is about to be re-described as a dromie (thanks for the info Darren):
(http://www.cmnh.org/fun/dinosaur-archive/1999Dec/msg00056.html).


There's also scrappy limb material from the Morrizon (including _Palaeopteryx_), which could be either avian or dromie.

The subject of _Protoavis_ has come up. I've just been reading some of John Ostrom's comments on this critter. Ouch! He doesn't hold back. Anyway, has there been any published illustrations of the *original* _Protoavis_ material. In other words, are there pictures ANYWHERE of what the bones looked like when they came out of the ground, rather than just Chatterjee's interpretations of what they are.


Tim

------------------------------------------------------------

Dr Timothy J. Williams

USDA/ARS Researcher
Agronomy Hall
Iowa State University
Ames IA 50014

Phone: 515 294 9233
Fax:   515 294 3163

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