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[...] Rauhut [...] makes many species metataxa, which I feel is
inappropriate.
What is a metataxon?
The paraphyletic traditional Ceratosauria is also seen in Carrano and
Sampson 1999. The characters traditionally used to support the
Ceratosauria are rather problematic-
[...]
The neoceratosaur-tetanurine clade is supported
by fifteen synapomorphies- [...] It has a bootstrap of 90% and it takes 13
more steps to make the traditional Ceratosauria
monophyletic.
Sounds like good evidence.
How is Neotheropoda defined at the moment?
Seven additional synapomorphies were found
(premaxillary body in front of external nares longer than body below the
nares, and angle between anterior margin of the premaxilla and alveolar margin
less than 70 degrees; presence of a constriction between the articulated
premaxillaries and maxillaries;
Are these three related to the subnarial
gap?
the lateral rims of the nasals are pronounced and
form raised edges; no contact between the squamosal and quadratojugal;
presence of enlarged, fang-like teeth in the anterior part of the
dentaries;
I've often seen "no fanglike teeth in the
dentary" used as an apomorphy of Tetanurae, implying that their presence is
plesiomorphic. Where does this attitude come from?
[...]
Only three steps are needed to make a traditional
Coelophysoidea, but if Shuvosaurus is excluded it is just as parsimonious as
the tree presented above. This is because the latter taxon lacks a few
of the proposed traditional coelophysoid characters- it lacks a subnarial gap
and a constriction between the premaxillaries and maxillaries, the lateral
margins of the nasals are not raised, and the squamosal contacts the
quadratojugal.
This is suggestive...
Shuvosaurus is a coelophysid based on two
characters shared with Syntarsus- forked posterior end of the premaxilla,
considerably elongated basisphenoid.
I can't judge that, but these characters sound pretty weak,
IMHO.
He suggests Genusaurus is closer to Carnotaurus
than Majungatholus, based on the straight dorsal ilial margin and very long
vertically oriented ischial peduncle.
:-o
The Carnosauria clade, containing both
traditional carnosaurs, as well as megalosaurs and spinosaurs, is supported by
only three synapomorphies- ascending process of the maxillary offset from the
anterior rim of the maxillary body and anterior projection of the maxillary
body longer than high;
Related to the typical skull shape of most
large theropods?
cervical vertebrae strongly
opisthocoelous;
Would this add rigidity or
flexibility?
metacarpal I very stout and approximately as
broad as long.
Sounds like a plesiomorphy,
AFAIK...
Eustreptospondylus is made a junior synonym of
Magnosaurus, to form the new combination Magnosaurus oxoniensis. This is
because they share the following characters- slight dorsoventral and
transverse expansion of anterior dentary; significantly enlarged third dentary
tooth; shallow longitudinal groove with rectangular cross section in
dentary. Also, the remains of both are almost indistinguishable,
differing only in slight differences in the proximal extent of the pubic
apron. I think this sounds probable, but cannot comment due to the lack
of proper references on either.
Interesting... is Magnosaurus no longer considered a
nomen dubium (in which case the much more beautiful name
Eustreptospondylus could remain...)?
Rauhut notes that Yangchuanosaurus shangyouensis,
Y. magnus, Sinraptor dongi and S. hepingensis are all nearly identical in
morphology. Additionally, all but S. dongi are from the same
formation. He suggests they may be synonymous, which would make
Yangchuanosaurus shangyouensis the correct name. However, he has
not examined them firsthand, so provisionally keeps them
separate.
Metriacanthosaurus was not included because it
scored identically to sinraptorids.
This sounds a lot like PDW (where Yangchuanosaurus was
lumped into Metriacanthosaurus).
Rauhut notes Deltadromeus has a well
developed anteromedial ridge on the distal femur. This is more
similar to ceratosaurs than coelurosaurs. Additionally, the
anteroposteriorly long proximal caudal neural spines, reduced fourth
metatarsal and proximally unreduced third metatarsal have me thinking of
Elaphrosaurus after all the time I spent looking at the latter genus for
"Details on Chuandongocoelurus".
I'm already waiting that Dryptosaurus becomes a
ceratosaur... ~:-|
Rauhut assigned Bahariasaurus to the
Carcharodontosauridae in 1995 based on characters of referred material.
The holotype is said to lack carcharodontosaurid synapomorphies and be very
close (if not identical) to Deltadromeus.
So it's back in incertae sedis?
The absence of transverse processes in
Compsognathus is no longer certain. There is a large crack running
through the caudal series which makes it impossible to determine their
presence.
Sinosauropteryx has, IIRC, lots of
them.
Rauhut still coded AMNH 587 (the referred manus)
as Ornitholestes, while it is now known to be Coelurus, which may have had an
adverse affect on the analysis.
Ah, it is Coelurus rather than
Ornitholestes... this explains quite some confusion I had with
it.
Ornitholestes does not have a nasal horn (contra
Paul, 1988), as "the apparent upward flexure of the posterior border of the
external nares on the left side of the skull is caused by a break and
subsequent ventral displacement of the ascending process of the maxilla and
the nasals."
Rauhut notes that there are no comparable
elements in Piveteausaurus and Proceratosaurus, so their referral to the same
family and genus by Paul (1988) is unfounded. Piveteausaurus differs
quite a bit from Ornitholestes, to which it can be
compared.
In short, any Ornitholestidae is obsolete. I'll have to treat them
all separately... ;-(
It is human to err, but if you want to produce real trash, you need a
computer.
Relatively Old
Proverb
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