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Nick Longrich wrote-
Sinraptor also appears to have had a pubic foramen, unlike Allosaurus which
lacks the foramen, as in coelurosaurs. If you threw more taxa into this matrix,
and then a few more characters, you'd probably start seeing several
different carnosaur groupings.
Ah, the old idea of allosaurids being closer to
coelurosaurs than sinraptorids and carcharodontosaurids. Replaced by the
new consensus of all three groups in a Carnosauria. Sinraptor dongi has an
open obturator notch, as do your more basal Acrocanthosaurus and
Giganotosaurus. On the other hand, the Santana compsognathid has an
obturator foramen in one pubis. Confusing situation, as usual. Then
there's your placement of carcharodontosaurids by sinraptorids, not allosaurids,
opposite of the current consensus. Personally, I like a Carnosauria
including sinraptorids and a carcharodontosaurid-allosaurid clade, with
torvosaurs and spinosaurs further down, but it's not like I've run an
analysis.
I've seen no evidence that Afrovenator has either the maxillary fenestra or
obturator process it's illustrated with, and therefore it's a good candidate for
being a Torvosaurus relative.
How interesting...
Finally, it's useful because if one of your supposedly derived taxa
actually turns out to be more basal, it can fall down the tree in its correct
spot instead of being stuck in with a bunch of taxa it doesn't belong with.
Indeed. Siamotyrannus is always falling to
the base with Allosaurus in my trees.
With respect to
Deinonychosauria, there are a fair number of features holding this group
together; they include things like a large triangular lateral exposure of the
splenial, ventrally flattened and anteriorly forked chevrons, the enlarged
ungual of pedal digit II, and a spine table on the dorsals. Some of these
features are also known from things such as Rahonavis or Unenlagia as well. I
think the case for dromaeosaurid monophyly is going to be pretty good, the
Dromaeosaurus skull is pretty weird but the postcrania is pretty standard and in
the details looks like a lot Velociraptor, Saurornitholestes, and Deinonychus.
Look at the possibility that the most birdlike, "derived" dromaeosaur-type
critters (e.g. Sinornithosaurus) are in fact the *primitive* ones.
I do have those characters in my analysis, but
they're not making a Deinonychosauria that includes Troodontidae-
79. splenial exposed broadly laterally
124. apices of dorsal neural spines expanded
transversely to form spine table
272. pedal ungual II enlarged
339. distal chevrons with caudal
bifurcations
Perhaps these are symplesiomorphic
troodontid+eumaniraptoran characters reversed in derived avialans. What
Dromaeosaurus postcrania are you using to compare to other dromaeosaurids?
The pedal phalanges? ;-) I agree that dromaeosaurids seems
secondarily primitive in several characters, with the more avian Bambiraptor
being a more basal deinonychosaur. Sinornithosaurus still comes out as an
avialan though.
Alvarezsaurs... still a
problem. The hindlimbs seem to suggest an oviraptorosaur-grade theropod, the
lack of similarly derived forelimbs could be a result of their highly
specialized morphology, but it's hard to say. A complete Alvarezsaurus or
Patagonykus will be crucial in figuring these things out, but I think that it's
clear they're probably not avialan and definitely not ornithomimid, but are some
sort of Maniraptora.
I agree here- non-eumaniraptoran paravians in my
trees.
Mickey Mortimer
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