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RE: Dromeo Danger



That sounds like a very interesting snake. And it is
certainly possible that dromeosaurs subsisted on
'small' prey. Perhaps they specialized in pterosaur
snacking, for instance.

That said, the apparent lack of "power" may be
deceptive. I think that if someone handed you a
functional replica of a dromeosaurid jaw, and
instructed you to cut something w/ it, you would
quickly find that it cut best on the backstroke, and 
would inevitably end up using it like a pruning saw.

This is not a technique that requires a great deal of
compressive power (i.e., downward force on the "saw").
Indeed, struggle by prey, and/or the bodyweight of the
predator, could easily supply the power needed to
shear flesh, particularly bone-free muscle. (There is
an old saying; "More than a mouthful is a waste..." :)

To use another gardening analogy, it is difficult to
imagine a re-curved tooth that is serrated on the rear
edge being primarily used in the same fashion as
pruning shears.

Don

--- John Scanlon <riversleigh@outbackatisa.com.au>
wrote:

> 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
> >
>
___________________________________________________________________
> > 
> 
> 
> 
>