Jengizkhan, Stygimoloch, Dinotyrannus (long)

[Tom Holtz <tholtz@geochange.er.usgs.gov>]

>I am a Japanese reader of this mailing list.
>The latest Japanese dinosaur magazine (Kyoryugaku Saizensen
>No.9, ISBN4-05-600851-5) reported the history of North American
>and Asian Tyrannosaurid discovery, by George Olshevsky.
>He think there are three genera of Tyrannosaurid in the Nemegto
>basin, Tyrannosaur bataar, Tarbosaur efremovi, Maleevosaur
>novojilovi, respectively.
>And he think Tyrannosaur bataar is neither Tyarnnosaur nor
>Tarbosaur, so he want to rename Tyrannosaurs batarr as
>Jenghizhkan bataar.

G. Olshevsky is "proposing" several new tyrannosaurid generic names in his
two-part article in the Japanese magazine Kyoryugaku Saizensen ("Frontiers
of Dinosaur Research", but more commonly called "Dino-Frontline" in
English).  However, since these are not peer-reviewed articles, the names
are not considered "valid".  So, even if some of the suggested new names
may be useful, they will not be accepted for scientific usage until
published in a peer reviewed journal.

That said, here are some of the "new" names:

Jenghizkhan bataar (formerly Tyrannosaurus bataar): a species with a
confusing history, now given a new generic name.  The type of "J." bataar
is a skull, which Maleev (in 1955) names Tyrannosaurus bataar.  He
considered it a) the same genus as T. rex and b) distinct from the other
Asian tyrannosaurids (esp. Tarbosaurus efremovi).  Greg Paul and Ken
Carpenter (and me, following their work) have considered all the big
Mongolian tyrannosaurids the same species (for with the trivial name
"bataar" has priority), and considered it the same genus as the North
American T. rex.

Olshevsky, however, considers the type of "bataar" as distinct from
Tarbosaurus efremovi, and considers some of the material refered to T.
efremovi as being from juvenile "bataar"s.  Furthermore, Olshevsky
considers "bataar" to be a distinct genus from Tyrannosaurus, which is
convergent in many features with the North American giant.  So, giving the
Mongolian giant the title of Mongolia's greatest warrior, he has
(not-yet-officially) proposed the name Jenghizkhan bataar for this species.

Stygivenator molnari is the "Jordan theropod", a small tyrannosaurid found
a couple of decades ago and described by Ralph Molnar and Ken Carpenter as
referrable to the tooth-genus Aublysodon.  Olshevsky considers the type of
Aublysodon as invalid, and has proposed this new name (meaning "Hell Creek
hunter").  This might not be a bad idea, especially if "aublysodontine"
teeth are found in more than one distinct genera of tyrannosaurids (which
hasn't been shown yet).

Dinotyrannus megagracilis is Greg Paul's Albertosaurus? megagracilis, a
tyrannosaurid intermediate in size between T. rex and Nanotyrannus.  I
don't know if anyone else out there thinks this is a valid species (Ralph?
Ken?).  Greg Paul has since revised his idea, and considers the specimen to
be a subadult T. rex.  [Aside: It was on this opinion that I took A.?
megagracilis out of my tyrannosaurid list in the J. Paleontology paper, in
case any of the readers saw the manuscript in prepublished form.].

Anyway, I'm looking forward to my copy of "Dino-Frontline".  I can't wait
to see "Ho-ru-tsu" (=Holtz) in katakana... ;-)

                                
Thomas R. Holtz, Jr.                                   
tholtz@geochange.er.usgs.gov
Vertebrate Paleontologist in Exile                  Phone:      703-648-5280
U.S. Geological Survey                                FAX:      703-648-5420
Branch of Paleontology & Stratigraphy
MS 970 National Center
Reston, VA  22092
U.S.A.