[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Alxasaurus and segnosaurs



In a message dated 96-02-06 14:01:15 EST, martz@holly.ColoState.EDU (Jeffrey
Martz) writes:

>> >      Is is remotely possible the segnosaurs are paraphyletic?
>> 
>>     I think that this would SUCK! Or as people say from Seattle LAME!
>>      IMHO, I think you mean Polyphyletic?

Ah--more lofty, elevated scientific discourse.

Segnosaurs could be paraphyletic if you found the common ancestor of
Ornithischia and Segnosauria, and it turned out to resemble a segnosaur more
than an ornithischian or a prosauropod. Otherwise, probably not; I know of no
dinosaur group outside of Ornithischia that could possibly have derived from
segnosaurs.

But you probably meant "polyphyletic," right? So far, all known segnosaurs
are strongly united by numerous synapomorphies in pelvic and limb anatomy.
Where known, skull material of the various genera is also quite similar.
Polyphyly of the known genera is highly unlikely.