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

Re: Megalosaurids



Mickey Mortimer (Mickey_Mortimer111@msn.com) wrote:

<Magnosaurus nethercombensis is very close if not congeneric with
Eustreptospondylus, so is a spinosauroid (Rauhut, 2000).  "Walkersaurus"
hesperis is a non-avetheropod tetanurine (Holtz, 2000).  Xuanhanosaurus is
a non-coelurosaur tetanurine (Rauhut, 2000).  Iliosuchus just might be a
basal tyrannosauroid, as Stokesosaurus probably is (Holtz, 2001). 
Segisaurus is a coelophysoid (Rauhut, 2000).>

  Beleive it or not, the generality that Paul's PDW is out of date
therefore much of it is invalid is not accurate. Much of PDW is in fact
very valid, including the systematics. The difference between species of
coelophysines and velociraptorines are largely matters of taste, and Paul
has done an admirable job of facing the opposition in proposing some
difficult ideas for some, especially lumping species to create a broad
sense of the "generic" concept. 

  However, *"Megalosaurus" hesperis* has some interesting features I'd
like to talk about that suggests it's immediate affinities are in a
broadly spinosauroid clade: first, interdental plates are fused, a
condition seen in the spinosauroids (as currently diagnosed by Sereno,
*Torvosaurus* + *Spinosaurus*); second, the mesial ("rostral") lobe of the
maxilla is much longer than it is tall, resulting in what can be
corrollary to retraction of the nares, or expansion of them. The latter is
seen in the "pseudo"-carnosaur *Monolophosaurus*. The "lobe" is also
roughly rectangular, rather than triangular as in most theropods with an
expanded rostral lobe. These suggest that an animal I tentatively call a
psuedo-sucho ancestor (or Protosuchoides) was a primtive spinosauroid.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

__________________________________________________
Do You Yahoo!?
Yahoo! Health - Feel better, live better
http://health.yahoo.com