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RE: Dromeo Danger



Don and all,

Apart from varanids, I have one other example in Recent squamates of
laterally compressed, serrated and recurved teeth.  A reticulated python
(Broghammerus(!?!**) reticulatus) obtained by Mike Archer and colleagues
from a restaurant in Sarawak has this condition, though it's certainly not
typical of the species. Like most snakes, pythons normally* have recurved
but more or less conical teeth with smooth cutting ridges (anterolateral and
posteromedial) extending along part of the crown and meeting to create a
blade-like tip. This one specimen has anterior and posterior ridges and the
teeth are laterally compressed from base to tip, the edges not denticulate
as in varanids but slightly 'rippled' which would apparently work as
serrations. Until further examples are known (or I get round to properly
describing this one, at least), no phylogenetic or functional significance
should be attributed.  
I've been bitten and (separately) constricted by pythons around 3 m long,
and I've seen a large Varanus varius locked onto somebody's hand (it was
eventually removed with a crowbar, with considerable shedding of blood), so
I can imagine how unpleasant an attack from a serrate-toothed reticulated
python would be. 
Even so, no large snake has evolved the ability to sever chunks from
vertebrate prey and eat it piecemeal, and I regard it as possible that
lightly built dromaeosaurs did not do so either, but stuck to prey not much
bigger than their own head, swallowing items whole with the help of
intramandibular kinesis. They look overengineered, but possibly underpowered
for actually dismembering large prey.

See: 
*Frazzetta, T.H. 1966. Studies on the morphology and function of the skull
in the Boidae (Serpentes), Part II. Morphology and function of the jaw
apparatus in Python sebae and Python molurus.  Journal of Morphology 118:
217-296.
**Rawlings, L.H., D.L. Rabosky, S.C. Donnellan and M.N. Hutchinson. 2008.
Python phylogenetics: inference from morphology and mitochondrial DNA.
Biological Journal of the Linnean Society 93: 603-619.
-----------------------------------------------
Dr John D. Scanlon, FCD
Riversleigh Fossil Centre, Outback at Isa
riversleigh@outbackatisa.com.au
http://tinyurl.com/f2rby
 
"Get this $%#@* python off me!", said Tom laocoonically.

-----Original Message-----
From: don ohmes [mailto:d_ohmes@yahoo.com] 
Sent: 03 April, 2008 9:17 AM
To: dinosaur@usc.edu
Subject: Re: Dromeo Danger

As a shy and sensitive type, I've always observed
nearby teeth w/ some interest, and listened carefully.

Serrated teeth say, "Hi, I have to cut my food up
before I eat it, and further, my food is not
necessarily dead when I do so (unlike a lion, for
example). Nor do I spend a lot of time eating bones,
even small ones." When the teeth are serrated AND
recurved, I seem to hear them say, "Whatever part of
you I manage get in my mouth, I will keep. Even if we
part ways, you will leave it behind."

Do you think this hallucination, er, I mean
observation, uh, speculation re behavior is
reasonable? 

In the dromeo case, the rear claws are perfect for
providing traction when grabbing a mouthful and
pulling back really hard when attacking a larger
animal (ala Manning et. al). 

I've spent a lot of time working on vertical surfaces
(ie, tree trunks), and I can testify that to pull back
(as on a hand saw, or a rope) you MUST have a firm
foothold.

Don

--- Dann Pigdon <dannj@alphalink.com.au> wrote:

> don ohmes writes: 
> 
> > Heh. I live in a place that has coyotes aplenty. I
> > hear them several times a week, and can find fresh
> > scat w/in 100m of the house easily. Unless I work
> at
> > it, I see ZERO coyotes. On the other hand, I get
> > attacked by mockingbirds pretty regular, in
> season.
> 
> Being small, volant, quick and very manouevrable
> tends to 'embiggen' the 
> smallest of creatures. :) 
> 
> Here in Australia the boldest bird would have to be
> the willy wag-tail 
> (Rhipidura leucophrys) - a tiny insect eater that
> will gladly take on a 
> magpie or a crow (known nest raiders) in single
> combat despite mass 
> diffences of several orders of magnitude. Their
> aerial agility makes them 
> almost immune to reprisals, so most of their victims
> don't bother making the 
> effort anyway. 
> 
> If willy wag-tails will attack magpies, and magpies
> will themselves attack 
> wedge-tailed eagles (as my mother witnessed in her
> own front yard; the 
> aftermath including a lot of damaged and destroyed
> potted plants), then that 
> would seem to make the willy wag-tail the baddest
> mo-fo on the block. Look 
> upon it's fearsome visage with awe:
> http://thumbs.photo.net/photo/2879863-sm.jpg 
> 
> > Another point; sharks don't necessarily packhunt,
> but
> > they do tend to gather at the site of a ruckus.
> 
> Great Whites have been known to hunt in pairs on
> occasions, but in many 
> respects they're more like a mammal than a fish.
> Reef sharks will hunt 
> together in groups, but it's not what you'd call
> cooperative hunting (more 
> like an angry mob). 
> 
> > BTW -- Sharks are the best extant velociraptor
> > 'tooth-analogue' I know of. 
> > Are there any other candidates?
> 
> Monitor lizards come to mind. 
> 
>
___________________________________________________________________
> 
> 
> Dann Pigdon
> GIS / Archaeologist             
> http://geo_cities.com/dannsdinosaurs
> Melbourne, Australia            
> http://heretichides.soffiles.com
>
___________________________________________________________________
>