Re: Megalosaurs

[jrw6f@faraday.clas.virginia.edu]

Tim Williams wrote (note that Tom Holtz is quoting me... argh!):

>Tom Holtz wrote: 
>> _Poekilopleuron_ may be _Megalosaurus_.  The case for a monophyletic
>> Megalosauridae (_Torvosaurus_, _Poekilopleuron_, _Megalosaurus
>> bucklandi_) is growing.
>
>What about other so-called megalosaurids like _Proceratosaurus_, 
>_Marshosaurus_, _Metriacanthosaurus_, _Xuanhanosaurus_ (which, I 
>think, has massive forearms and shoulders like _Torvosaurus_).
        Is Metriacanthosaurus complete enough for analysis?
        If you mean Paul's Metriacanthosaurus, ie.
Szechuanosaurus+Yangchuanosaurus+Met., Sereno (and perhaps others) makes a
good case for Yangchuanosaurus (does anyone else hate place-named genera?)
being a sister to Sinraptor in the Allosauroidea, and I think it's likely
that Szechunaosaurus is also in there.
        Proceratosaurus:  Since this species is known from only a skull,
and complete skulls are not known for any of the three megalosaurids
mentioned above, it's difficult to tell.  Based on a handful of diagnostic
characters, it is probably a coelurosaur.  It is likely that the
Ornitholestinae (Paul, 1988.  Probably best elevated to a family) are
monophyletic, lacking more data.
        Marshosaurus:  Pass...
        Xuanhanosaurus:  Wish I read chinese...

>> >     4)  Eustreptospondylus and Piatznykisaurus[sic-Wagner]... pass
>
>Sereno et al.'s paper on _Afrovenator_ classified _Eustreptospondylus_
>as a torvosaurid, if I remember correctly.
        I wouldn't be surprised if the two form a monophyletic clade, I
would be surprized if that clade didn't include Piatnitzkysaurus and
Megalosaurus or Poikilopleuron.

>One source (I think it was Lambert's _Ultimate Dinosaur_) listed
>_Piatnitzkysaurus_ as an abelisaurid.  Any comments?
        It is pretty basal Tetanuran, so I guess it could be...  I don't
think it shows any abelisaurid characters, but since it doesn't look like
anyone is keen on include it in their cladograms, there doesn't seem to be
a recent analysis of the taxon.  My cladeogram, and my personal oppinion,
waffles between Megalosauridae (Torvosaurinae + Megalosaurus) and
intermediate neotetanuran, possible close to Eustreptospondylus.

>By the way, the paper on _Carcharodontosaurus_ and _Deltadromeus_
>mentioned that at an abelisaur had been discovered in Africa.  Does
>anyone have the details?
        Yeah, I saw that too.  Intriguing!  I believe, but I'm not sure,
that this is part of the Charcharodontosaurus-as-abelisaur theory that has
been put up (I believe Holtz, mentions it in the big paper (1994)).  Then
again, Sereno et al. seem bent on dropping tantelizing little hints (many
of them about Russel's work, although he doesn't ever mention that
significant portions of the skeleton of Spinosaurus have been found.  Which
may not mean anything...).  I haven't completely worked through the notes
and ref.s, but I don't remember seeing anything that looked like diagnostic
abelisaur material from Africa.  Anyone?
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