Re: Archaeopteryx and 'sickle-claw' info questions

["T. Mike Keesey" <tkeese1@gl.umbc.edu>]

On Tue, 3 Mar 1998, StarGazer / the NightRyche wrote:

> Hi :>
> 
> In G. Paul's Predatory Dinosaurs of the World, he reconstructs 
> Arachaeopteryx as possessing a 'sickle-claw', much like a miniature 
> version of the one Velociraptor has.  Has this been disproven, or is 
> it still a possibility?

So far as I have heard, it did have a hyperextendable second pedal digit
(although the ungual was not significantly larger than the other pedal
unguals, as in other "sickle-claws").
 
> For that matter, how many 'sickle-clawed' dinosaurs/birds are out 
> there?  And is there any place I can find information about them on 
> the Net? 

There were three radiations that we know of. _Noasaurus_, an abelisaur,
had a large "sickle claw" that was different in morphology from the other
two radiations. Troodontids were once grouped with dromaeosaurids (a.k.a. 
"'raptors") because of their similar "sickle claws", although they are now
generally recognized as a separate lineage, closerr to ornithomimosaurs
(a.k.a. "ostrich mimics"). Primitive paravians, including dromaeosaurids
and _Archaeopteryx_, as well as the enantiornithine _Vorona_ and the
unnamed "flying 'raptor" of Madagascar, also show the trait, although
various advanced paravian lineages (including modern birds) have lost it. 

For more, see:
http://umbc.edu/~tkeese1/neocerat.htm -- _Noasaurus_
......................../troodont.htm -- Troodontidae
......................../coeluros.htm -- Paraves

--T. Mike Keesey
tkeese1@gl.umbc.edu
DINOSAUR WEB PAGES -- http://www.gl.umbc.edu/~tkeese1/dinosaur/index.htm