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Re: Carnosaurs and friends (was Re: Eustreptospondylus)



In a message dated 96-06-05 10:48:57 EDT,
T.Williams@cclru.randwick.unsw.edu.au (Tim Williams) writes:

>I don't like the name "Carnosauria".  Since it was first coined (?by
>Huene) I think it's essentially been redefined out of existence.  For
>the clade including _Allosaurus_, _Sinraptor_ [...] etc I would name
>"Allosauria".  

I've seen others do that, too.  Whatever floats your boat, as far as I'm
concerned.  I've gotten used to the new definition of "Carnosauria."  

>I would retain the term Carnosauria only for convenience - as a
>paraphyletic group embracing the Megalosauria and Allosauria.

Why retain it at all, in that case?


>> Allosauridae [_Allosaurus_, _Saurophaganax_, _Giganotosaurus_,
>> ?_Chilantaisaurus_, and probably new stuff from England and France];

>I like _Chilantaisaurus_ better as a megalosaur.  (I'm not even sure 
>if _C. tashuikoensis_ and _C. maortuensis_ belong to the same genus)

After taking another look at the metatarsals (about all I've seen of
_Chilantaisaurus_), I think you might be right, about
_C. tashuikouensis_, anyway.  Incidentally, I fail to see how anyone
could think that the metatarsal morphology in this species is
intermediate between allosaurs and tyrannosaurs.

And I now consider _Giganotosaurus_ a carcharodontosaurid.

>Nick says:

>> Sinraptoridae [_Sinraptor_, _Yangchuanosaurus_, _Szechuanosaurus_,
>> _Metriacanthosaurus_, ?_Gasosaurus_/_Kaijiangosaurus_, and
>> ?_Marshosaurus_];

>Could _Szechuanosaurus_ be an allosaurid?
>I'm glad you mentioned _Gaso_ and _Kaijiango_, Nick.  What is the 
>situation with these too - are they same?  And are they sinraptorids?

_Szechuanosaurus_ is usually classed as an allosaurid, but its pubic
boot is only expanded caudally, it has a low flange on the
posterodorsal surface of its ischium, and its ischium ends in a
cranially-directed hook.  These are all sinraptorid features.

As for _Gasosaurus_ and _Kaijiangosaurus_, I do not know whether they
are one species or two.  _Kaijiangosaurus lini_ He, 1984 has priority
over _Gasosaurus constructus_ Dong & Tang, 1985, BTW.

_Gasosaurus_ appears to have a quadrangular obturator flange, which
would make it a carnosaur at least as advanced as _Afrovenator_.  The
scapulocoracoid of _Kaijiangosaurus_ is comparable to either
_Allosaurus_ or _Sinraptor_.  The pubis of _Gasosaurus_, while little
expanded, appears to flare both cranially and caudally.  The ischium
narrows sharply distal to the obturator flange and is flared, rather
than hooked, at the end.  The ilium is just plain weird; I almost
wonder if it has been reconstructed correctly.

I put _Gasosaurus_ tentatively in the Sinraptoridae before because it
is Chinese.  However, the features cited above suggest that it was
actually an early member of the allosaur-carcharodontosaur line.  I
wish I knew whether _G. constructus_ is synonymous with _K. lini_, but
I don't have enough information.

A few cranial features suggest that _Cryolophosaurus_ may be an
allosaurid or close to it.  Does anyone know if there has been
anything published on the pelvis of this species?

>> and Carcharodontosauridae [_Acrocanthosaurus_, _Bahariasaurus_,
>> _Carcharodontosaurus_]).
>
> _Bahariasaurus_ and _Deltadromeus_ are probably basal coelurosaurs -
> the paper by Paul Sereno (and his small army of co-authors) on
> _Carcharodontosaurus_ established this quite well.  Their closest
> relative may be _Dryptosaurus_.

True, _Deltadromeus_ material had been referred to _Bahariasaurus_ in
the past, but I read Sereno et al. as rather noncommittal on the
status of the holotypic material for _B. ingens_.  He didn't include
it in his character matrix or in his cladogram.  Was he intending to
say that _Bahariasaurus_ and _Deltadromeus_ are related?  Rahaut said
_B. ingens_ was a carcharodontosaur.

I agree that _Deltadromeus_ looks like _Dryptosaurus_, particularly
the fourth metatarsals.

BTW, what does anyone out there know about _Labocania_?  It appears to
be a large, primitive coelurosaur (triangular obturator flange, no
D-sectioned teeth).  Is it possible that it, too, is a dryptosaur?

Nick Pharris
Olympia, WA