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SOME OBSERVATIONS CONCERNING BASAL ORNITHOPODS AND OTHER MEANDERINGS



BUGENASAURA'S RELATIONSHIPS

Having just recieved the paper where Galton names _Bugenasaura infernalis_
and the paper where Morris illustrates this same beast as _Thescelosaurus
sp._ some 20 years earlier (thanks again Darren), I have noticed some strange
things about said beast.

Some features I've noticed lead me to believe that _Bugenasaura_ may be a
North American endemic relative of the mid-Jurassic Chinese _Agilisaurus
louderbacki_.  These include:

1) an extremely long and straight palpebral.  In _Agilisaurus louderbacki_,
the palpebral also contacts the postorbital caudally.  The condition is
unknown in _Bugenasaura_ because the distal palpebral is missing as well as
most of the postorbital.

2) a very pronounced maxilla-jugal overhang, ie a deeply recessed maxillary
tooth row with substantial attachment area for cheeks, more so than in most
ornithischians.

3) a relatively slender postorbital/jugal bar compared to many other basal
ornithopods, and also in relation to the overall robustness of the two
species' skulls.

I think that these characters, as well as (possibly) tooth characters (as
soon as someone spends the time actually examine their teeth in great detail
and perhaps publish some drawings...), will show that these two are sister
taxa.  I also believe that Peng's placement of _Yandusaurus multidens_ into
_Agilisaurus_ is probably not correct.  He is certainly correct in removing
it from _Yandusaurus_, but I have a feeling that it may form a clade with
_Othnielia rex_ and _Drinker nisti_ based on skeletal and tooth similarities.

THE RECENT ISSUE OF THE DINOSAUR REPORT

In this issue, there is an article by Thom Holmes on _Sinosauropteryx_ which
simply reitterates the Society's dogmatic anti-feather stance with glee.
 Though I surely agree with the Ostrom/Brush/Wellnhoffer/Martin/Bubier team
that the structures aren't feathers _per se_, but I think some of Holmes'
statements are just his speculation and a lot of TDSI anti-feather
propaganda.  For instance, he writes:

"They are not 'proto-fetahers' because they post-date the appearance of
_Archaeopetryx_ which has fully developed feathers."

WHAT?  Who ever taught Holmes evolutionary biology did not quite get the
point across that plesiomorphic features do not disappear in some sister
lineages.  Jeez, if this were true, there would be no creatures with gills.
 Anyways, enough of my rant....

As for me, I think that the structures will turn out to be stiff, hollow,
hair-like shafts, homologous to pterosaur 'hair', and ultimately homologous
to the central shafts of bird feathers.  But then, we will just have to wait
and see.  They are certainly not any part of a frill like those seen in
lizards because there are clear areas where the shafts overlap and where the
seperate that are easily visible even with the macroscopic pictures published
in _Audubon_ (the one of the base of the neck is very telling in that
regard).

THE ARCHOSAURIAN COUP OF THE SVP

Also from the same issue of the Dinosaur Report, I see that the Sereno et
Wilson paper on sauropod phylogeny  is going to be out sometime soon and is
being called a monograph.  I am also looking forward to the description of "a
new small theropod" ("Nedcolbertia" I presume) by Mackovicky, and a
rediscription of _Chirostenotes_ by Sues.

Anyways, it's time for Pete to go and get a pager because his friends can
never get in touch with him.  Well, that's what they say....

Peter Buchholz
Tetanurae@aol.com

-------------------------------------------------------
Anonymous.  1997.  Dinosaur Society grants awarded in 1997.  The Dinosaur
Report Spring 1997:17.

Holmes, T.  1997.  Update on the Chinese "feathered" dinosaur.  The Dinosaur
Report Spring 1997:4-6.

Galton, P M.  1995.  The species of basal hypsilophodontid dinosaur
_Thescelosaurus_ Gilmore (Ornithischia: Ornithopoda) from the late Cretaceous
of North America.  N. Jb. Geol. Palaont., Abh. 198:297-311.

Morris, W J.  1976.  Hypsilophodont dinosaurs: a new species and comments on
their systematics.  In: Churcher, C S (ed): Athlon.  Essays on paleontology
in honour of Loris Shane Russel: 93-113; University of Toronto Press.

Peng G-Zh.  1990.  [A New Species of Ornithopod Type from Zigong, Sichuan].
 Journal of Zigong (issue number unknown): 19-30.  (In Chinese)

Peng G-Zh.  1992.  [Jurassic Ornithopod _Agilisaurus louderbacki_
(Ornithopoda: Fabrosauridae)    from Zigong, Sichuan, China].  Vertebrata
PalAsiatica 30(1): 39-53. (In Chinese with English summery)