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RE: Huge Theropod Database Update
David Howlett wrote-
> Good work :) although I would question your placement of
> Megaraptora within Coelurosauria when as I recall the family
> is accepted to be within the Carcharodontosauridae - in fact
> one member of the family, Neovenator, is still placed here
> by you.
Basically, I have a saurischian supermatrix that includes all the taxa and
codings from most of the recent large theropod analyses, and I added Benson et
al.'s (2010) data to it. And while his data supporting Megaraptora was strong
enough, his data supporting putting Megaraptora in Carnosauria was not.
Neovenator still ended up in Carnosauria though, while Chilantaisaurus had a
less certain placement. In addition to exaniming more characters than Benson's
analysis, I think one important difference in this case is that he only
included three coelurosaurs. Notably, all three (Tanycolagreus,
Proceratosaurus, Guanlong) are more derived than some other coelurosaurs
included in my analysis- Gasosaurus and tyrannosauroids. Which brings us to
> I'm also unsure why you have removed a number
> of taxa (including Eotyrannus and the Proceratosauridae)
> from the Tyrannosauroidia when as far as I am aware, they are
> firmly placed within the group.
I do address this in the comments section for each taxon, the most detailed of
which is for Dilong-
Several cladistic analyses have found this to be a basal tyrannosauroid. Xu et
al.'s (2004) analysis was a version of Currie et al.'s (2003) cranial-only
tyrannosaurid analysis, with Dilong and outgroups added. It is not that useful,
as the characters were designed to distinguish Allosaurus from tyrannosaurids,
and resolve relationships within Tyrannosauridae, so do not even lead to a
plausible outgroup topology (e.g. Citipati is the tyrannosauroid sister group).
Xu et al. (2006) added Dilong and Guanlong to Rauhut's (2003) theropod
analysis, which was followed by Benson (2008). Both Turner et al. (2007) and
Senter (2007) added Dilong to the Theropod Working Group's matrix, though the
latter contained more relevent tyrannosauroid characters. While Senter did find
it to be a tyrannosauroid, Turner et al. resolved it slightly closer to birds.
When I add the relevent taxa and all the characters used by Xu et al. (2006,
2004) to group Dilong with tyrannosauroids to Senter's (2007) matrix, Dilong
ends up one node closer to birds than to tyrannosaurids (along with apparently
related taxa Eotyrannus, Coelurus and Tanycolagreus). This is based on numerous
characters- in lateral view, dorsal border of the antorbital fossa formed by
the lacrimal and maxilla; round orbit; anterior cervical epipophyses absent or
poorly developed, not extending past posterior rim of postzygopophyses;
cervical neural spines dorsoventrally low; short laterotemporal fenestra;
posterior dorsal neural spines height <1.5× length; humeral length more than
half femoral length; manual phalanx I-1 longer than metacarpal II; feathers
present. Constraining Dilong to be a tyrannosauroid results in trees 2 steps
longer. It's still in the coelurid clade, but the latter is now the basalmost
clade of tyrannosauroids. At least some of the above characters could be
size-related, and Senter's matrix certainly has some character correlation
problems. Two steps isn't very much, so I don't feel a tyrannosauroid identity
can be ruled out. But at the same ti!
Li et al. (2009) added more relevent characters and taxa to the TWG matrix when
they described Xiongguanlong. I've added this data to my modified Senter
matrix as well, and Proceratosaurus, Eotyrannus, Guanlong, etc. still emerge as
closer to birds than tyrannosaurids. However, now we have Sinotyrannus,
Raptorex, Kileskus and the new data from adding Proceratosaurus and Guanlong to
Rauhut's matrix (Rauhut et al., 2010) and the data from adding those and
Kileskus to the Smith et al. matrix (Averianov et al., 2010). Will they end up
as tyrannosauroids once I incorporate that data? It's possible, and if so I'll
adjust my site accordingly.
Note that in both of these cases though, and as a general site rule, I do
describe what the current consensus is even if I vary from it. I want The
Theropod Database to be the ultimate repository for theropod information, not
just my platform to air my ideas.
The Theropod Database- http://home.comcast.net/~eoraptor/Home.html
The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with