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Re: Teeth



In a message dated 97-09-05 02:33:35 EDT, you write:

>    With replaceable teeth, they should be fairly common.  The hard part is
>  > finding out about their prevalence.   Full scale diagrams with cross
>  > sections could be produced that would act as a great field guide,
>  > especially for non dinosaur paleontologists.
>  >    Is there anyone working is the area?
>  
>       Actually, this is the exact thought that went through my mind 
>  about a year ago.  I came to the same conclusions as you and I guess this 
>  is going to be the next place where I focus my attention (i.e., hoping to 
>  fill this exact slot).
>  


Lets not forget about moi! While the Arundel Clay does contain bone and shell
material, the preponderance of the "complete" material recovered by me in 7-8
years of work are _teeth_! Naturally, my focus has been on identifying dinos
based mostly or entirely on teeth. And yes I know there is disagreement among
researchers in using this method but I have to work with what I have
available.


There are several "tooth genera" that were described from the Arundel from a
century ago. Additionally, the possibility is high that a couple more taxa
may now be included also based on teeth.

Arundel Genera based primarily on teeth:

Astrodon johnstoni (Leidy 1965) cf. "Pleurocoelus" sp. (Marsh). A prported
Brachiosaurid which may now be included with the Titanosuars?

Priconodon crassus (Marsh).  A Nodosaurid (Naked?) also based on it's rather
unusual tereth and some putative postcrania. 
"Goniopholis ""affinis "(Lull, 1911). Now regarded as a nomen dubium. Some
sort of crocodile with fluted, conical teeth usually less than 2cm long. 

I have teeth of one or two possible other crocs. 

>From my work, 1989- present and unpublished  thus far...

Deinonychus sp. - Teeth with the classic dromaeosaur morphology and virtually
identical to new specimens of D. anihrropus reported by Brinkman et al from
Oklahoma (Antlers Fm) as well as the traditional Cloverly form.

Acrocanthosaurus sp.- Large serrated teeth of  of Marsh's "Allosaurus"
"medius". based on my observations of the OMNH material, casts and of 'Fran",
it seems certain (and logical) that Acro's ranged the east coast.

"Bernaissartia" indet. - Two examples of the mushroom shaped crushing type of
back teeth of this form of croc.

Hybodus/Lissodus indet. - Tooth complexes (1-4 cusps/element, sorry i'm not a
shark guy) discovered by a friend whos assists me at the quarry. However, I
also do have two or three well preserved fin spines and a cephalic spine
attributable to  one or the other genus. 


Last but not least, 

"Magulodon muirkirkensis" (Kranz, 1996). n. nudum. Was named on the basis of
a single tooth found in 1990. This past April, I recovered only the second
tooth of this kind. It superficially resembles, somewhat, the P. crassus type
teth but it is smaller, more round with less pronounced denticles and a
prominent though not large, ridge. 
Possibilities of it's affinities include, some sort of Tenontosuar
(doubtful), Ceratopsian
(also doubtful based on those I have spoken with) and Hypsilophodont. I am
leaning for now in the direction of the latter . For now.
Hence my periodic posts seeking tooth info!

Let's talk!

Cheers!

Thomas R. Lipka
Paleontological/Geological Studies
http://members.aol.com/Tompaleo/Maryland.Dinosaurs.html