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R: Details on Adasaurus



----- Original Message -----
From: Mickey Mortimer <mickey_mortimer@email.msn.com>
To: <dinosaur@usc.edu>
Sent: Sunday, September 10, 2000 8:27 AM
Subject: Details on Adasaurus

> This has been considered a genus of dromaeosaurid, a species of
> Dromaeosaurus and something more closely related to therizinosaurs by
> various authors.  It also comes courtesy of Mike Keesey's wish for recent
> dromaeosaurids, before we get to the 90's species.
> Adasaurus Barsbold 1977
> A. mongoliensis Barsbold 1983
> = Dromaeosaurus mongoliensis Paul 1988
> middle Maastrichtian, LC
> Nemegt Formation, Mongolia
> holotype- (GI 100/20) (2.5 m) (old adult) incomplete skull and incomplete
> skeleton including ilium (202 mm), pubis (241 mm) and ischium (118 mm)
> referred- (GI 100/51) posterior postcranial skeleton including hindlimbs,
> phalanx II-1 (23 mm), phalanx II-2 (14 mm), pedal ungual II (28 mm)
> diagnosis- preacetabular processes strongly divergent; preacetabular
process
> strngly notched anteriorly; posterodorsal edge of postacetabular process
> very thick; distal ischium curved strongly posteriorly; metatarsal II
> reduced in width.
> Description-
> This genus was first only illustrated and labelled as Adasaurus in a short
> paper by Barsbold (1977), it was later described extremely briefly by
> Barsbold (1983).  The holotype specimen was approximately 2.5 meters long
if
> the ilium is scaled from Deinonychus.  It was from an old individual, so
> this is probably close to the maximum size Adasaurus got.  Because the
> specimen is pathologic (Norell and Makovicky 1997), some features of it's
> skeleton may not be representative of the species.
> There are skull remains, but all that is said regarding them is that they
> "bear a great similarity to other members of the subfamily, obviating the
> need to repeat general skull characters" (Barsbold 1983).  The subfamily
> referred to is the Dromaeosaurinae (with Dromaeosaurus, Adasaurus and
> Deinonychus), separated from the Velociraptorinae (with Velociraptor) by
the
> high, relatively large skull.

If I remember correctly Dinonychus is not a Dromaeosaurinae, but is a
Velociraptorinae (with Velociraptor and Saurornitholestes). Velociraptorinae
and Dromaeosaurinae are easily distinguished in their teeth. The serrations
on the front of the Dromaeosaurinae teeth are about the same size as the
serrations on the back of the same teeth. In Velociraptorinae, the posterior
serrations are much larger that the anterior one. And the premaxillary teeth
of the Dromaeosaurinae are all about the same size, whereas the second teeth
of this bone is the largest in Velociraptorina. Based on the Ostrom's
Deinonychus osteology (1969) the teeth of Deinonychus have all the charaters
tipical of the Velociraptorinae Dromaeosauridae, Utahraptor have a teeth
morphology much more similar to that of Dromaeosaurinae.

By
____________________________________________
Marisa Alessandro
"Volounteer of Paleontological Museum of Monfalcone"
Via Achille Grandi n°18
38068 ROVERETO (TN) ITALY
Tel:039-0464-434658 Email amaris@tin.it
____________________________________________