The Really Little, Little Guys, and Problems of Basing Total Size and Mass on the Size of Teeth Size

["Jaime A. Headden" <qilongia@yahoo.com>]

There, how's that for a paper title?

  Essentially, small dinosaurs have small teeth, but
don't base teeth size as the markers for body size
[or, read the title of the post]. I've been interested
in the developmental basis of small dinosaurs and the
endothermy/ectothermy debate as related thereupon,
especially in light of the question, "Were small
dinosaurs endothermic?" due to the principle that
smaller bodies give off more heat per area than large
bodies.

  Oh well, onto the subject. Teeth in small dinosaurs
depend, really, on diet, not body mass, though there
are exceptions. Small dinosaurs with relatively large
teeth happen to include "hypsilophodont" and
"fabrosaur"-grade ornithischians, heterodontosaurs and
basal ceratop[s]ians, and some thyreophores (see
appropriate articles in _the Dinosauria_). Very small
teeth in small dinosaurs occurs in troodontids only,
and this is unique, as far as I can tell, to the
group. The approx. 13ft (~3.5m) *Pelecanimimus*, with
the highest toothcount among the Theropoda, as a very
small head and very, very tiny teteh -- no measurement
off the top of my head, but if anyone has an available
copy of Perez-Moreno et al. 1993, please not be shy
and post it: I won't be able to reply untile tomorrow.

  Recently, the tiny new troodontid (named at SVP, but
for reasons [sensu Sloan, 1999] I refuse to post the
name, even in light of SVP's closing statements about
free reports by the press in scientific and justified
manners) was named, and was shown to not only have
very tiny teeth, thirty or so to the dentary in a
skull only about ~5in or about 2.5cm long, but to be
unserrated, in answer to someone's previous comment to
the list about unserrated troodont teeth. Not just the
premaxillary one's, either; the uppers and lowers,
all.

  I make a reasoning on small body size relative to
teeth size because diet can play havoc with tooth
morphology, size, or even prescence, and I'm talking
mammals here: take a comparative look at the skulls of
a hyena [say, *Crocuta*] and an aardwolf [*Proteles*],
both hyaenids, but the latter has almost half the
dental formula of the former; this is related to its
more insectivorous diet, as comparable to sparse
armadillo dentition, though other vermilinguans
(anteaters and tamanduas) lack teeth altogether. I
mention *Pelecanimimus* because looking at the
depressed, down-turned snout has afforded me an
interesting hypothesis: could it be insectivorous, or
perhaps more specifically, myrmecophagous? This is a
testable hypothesis, and one mark against it, one I
just discussed, is that Pele has the highest
toothcount among the theropods, and myrmecophages, by
observed data, reduce their dentition. However, I
would enjoin anyone to supply comments on this matter:
Myrmecophagy in Dinosauria. Please do offer comments
on segnosaurs, but that has been done extensively, and
I have written (here) on the subject, so check the
archives.

  Takers?

  Anyway, small teeth do not a small dinosaur make.


=====
Jaime "James" A. Headden

"Come the path that leads us to our fortune."

Qilong---is temporarily out of service.
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