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Re: Neovenator (was Re: Allosauria redefined)
At 03:34 PM 2/4/98 PST, you wrote:
>I've just recently had the chance to take a good look at the
>*Neovenator* from Surrey, England, and there seems to be a real
>interesting allocation of this theropod to the African
>carcharodontosaurids. Perusing the skeleton, and matching it with
>similar skeletons, I've found that the closest match was with
>*Afrovenator*. There a list of synapomorphies, which include:
>* broad scapula with shortend rectangular coracoid (Afro's is flanged
> at the end, while Neo's is not)
(Trying for his best Obi Wan) "Learn about character polarity, Jaemi..."
>* ischium is long a slender with small obturator process, and has a\
> distal boot (this feature is also shared with *Eustreptospondylus*
> from earlier beds (Oxford Clay) on the mainland)
>* the tibia has a very large cnemial process (another feature shared
> by a derived theropod, *Acrocanthosaurus*, to a greater degree and
> morphological similarity to that dinosaur)
>* the neural spines of the posterior caudals are hypershortened at
> the half point in the tail
Again, check polarities.
>* the maxilla is elongate
Damn, someone should really try clarifying exactly what is meant by this... :-]
>* the naris is expanded posteroanteriorly
A character common to many non-sinraptorid carnosaurs.
Similarity does not equal synapomorphy. Two forms may be more similar to
each other than to a third if the first two show the primitive state, and
the third the derived. That does not suggest a closer phylogenetic
relationship between the two primitive forms.
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:email@example.com
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661