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Major new paper on dromaeosaurids, with other significant maniraptoran info
I just got a reprint in the mail of an important new paper that will,
unfortunately, not be easy to get:
Senter, P., Barsold R., B.B. Britt & D.A. Burnham. 2004. Systematics and
evolution of Dromaeosauridae (Dinosauria, Theropoda). Bulletin of the Gunma
Museum of Natural History 8: 1-20.
A new phylogenetic analysis of dromaeosaurids and related taxa, with a
number of new character states examined. Here's the results in outline form
(OTUs marked with *):
even more adv. coelurosaurs
even more adv.
adv. Chinese microraptorians
even more droms.
Here's a review of the good stuff:
Senter et al. illustrate the primitive and derived states for their
characters. Good job! Some of the figures are a bit small, but you can at
least get what they are going for.
The authors regard Incivisosaurus a junior synonym of Protarchaeopteryx, but
different at the species level from P. robusta. The shared dentition pattern
(single pair of enlarged, anteroposteriorly comressed teeth in the front of
the premax; diminutive peglike teeth immediately behind those; diminutive
lanceolate posterior teeth; absence of teeth in the front of the dentary) is
their nain evidence for this. The differences at the species level are based
on different tooth count.
Troodontids come out as bullatosaurian arctometatarsalians. Whoa, now
that's something I haven't seen for years...
Sinovenator comes out as a basal deinonychosaur, and Senter et al. deal with
some of the miscodings of troodontid and/or Sinovenator characters in
previously published AMNH papers.
Microrapor zhaoianus, M. gui, and Cryptovolans wind up as sister taxa. In
fact, their only differences in the datamatrix are which cells are filled
and which "?". Characters that are supposed to be diagnostic for
Cryptovolans or for M. gui are either present in the other and in
Microraptor zhaoianus, or are unknown for those specimens. They recommend
that these are all conspecific, and so are really M. zhaoianus. I am very
much inclined to agree with them.
They discuss some of the features previously suggested by Paul as indicating
arboreality and/or volancy and/or secondary flighlessness in some
dromaeosaurids (feather vane asymmetry, morphology of manual phalanx II-1,
humeral diameter, position of metatarsal I, pedal phalangeal proportions).
In particular, they note that the simplest explanation in their phylogeny is
that for the most part parsimony supports independant derivation of the
dervied state in advanced birds and in Chinese microraptorians. So
regardless of whether or not these are indicative of flight in the Chinese
microraptorian clade, flight itself would not be preferred as the condition
in the most immediate common ancestor of flying birds and microraptorians.
Incidentally, this is perhaps the only technical dinosaur paper I know of
that uses a cartoon caveman for scale (Fig. 6)!!
Thomas R. Holtz, Jr.
Department of Geology Director, Earth, Life & Time Program
University of Maryland College Park Scholars
College Park, MD 20742
Phone: 301-405-4084 Email: firstname.lastname@example.org
Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796