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Various & Sundry (was RE: Dinosaur Genera List corrections #153 (JOKE))



> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Mickey_Mortimer
>
> I'm all for secondarily flightless maniraptorans, but isn't Aves
> is defined
> as the most recent common ancestor of Archaeopteryx and neornithines?

Well, that's one definition; the Gauthier definition is "all descendants of
the most recent common ancestor of tinamous, ratites, and neognaths" (in
other words, Neornithes of most authors).

> I have the Thulborn paper (1984).  It's one of the first theropod papers
> with a phylogenetic analysis and cladogram I know of.  For those
> of you who
> don't have it, Thulborn has a matrix of 29 characters and 15 taxa.

Whoa there.  It was an important early work, but as you state it it suggests
that this was an analysis run comprably to modern standards.  However, that
is not the case.  The "matrix" was not evaluated for parsimony analysis, and
thus the tree presented is not necessarily the most parsimonious tree.

>  His
> cladogram has the topology of (Coelophysidae (Compsognathidae +
> Dromaeosauridae (Allosauridae + Caenagnathoidea (Archaeopteryx
> (Tyrannosauridae ((Troodontidae + Ornithomimidae) (Avimimus
> (Enantiornithines (Ambiortus (Ichthyornis (Hesperornithiformes +
> Neornithes))))))))))).  Names have been modernized in some cases.  Wow,
> Bullatosauria in 1984, who'd have thought?

Indeed (although a troodontid-ornithomimosaur group had been suggested even
earlier by Kurzanov (1976: the _Itemirus_ paper).

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> David Marjanovic
>
> And I forgot to ask, are any oviraptorosaurian tail ends
> other than those of _Caudipteryx_ and _Nomingia_ known?

Tail ends are known from the pair of gorgeous soon-to-be-named specimens of
a new oviraptorid taxon in the Fighting Dinos display at the AMNH.  These
are non-pygostylous.

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Dino Guy and Computer Gal
>
> I had thought that juvenile tyrannosaurid legs were nearly identical to
> ornithomimid legs, but that they became bulkier and the femur:tibia ratio
> increased with age.  Is this true?

Yes, but please note that this is true for ALL non-avian theropods, not just
tyrannosaurids.  Baby ornithomimosaurs had small troodontid-like
proportions, for example.

> Perhaps, as Currie has suggested,
> smaller tyrannosaurids were runners, but their lifestyles changed as they
> grew larger and heavier.  Surely the hatchlings could have run and jumped,
> no?

Most experts agree (as they say in the commercials).  In the Farlow et al.
paper on the tripping _T. rex_, they point out that juvenile _Tyrannosaurus_
specimens or smaller adult tyrants might well have been more athletic than a
6 tonne adult big guy.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796