Re: BARYONYX

["Jaime Headden" <jaemei@hotmail.com>]

I don't study crocs, so I thought this would have been a good way of 
getting croc info into the Bary story, and guess what?
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                                                V

Paul Willis, aka Aussie, The Croc Guy:
<I see this word and I just can't help myself!>

Knew you wouldn't.

Part One, section two
<<< b: CROCODILES >>>

my theory:
Bary is not so analogous to bears and crocodiles.

It was pointed out to me that I was refering to _modern_ crocs, the 
forelimb I conveniently misplaced from the feeding discussion [bad 
boy!]. Read on:

theory the second:
Bary is actually quite similar in jaw structure to crocs, with a 
forelimb that is actually pretty good at "fishing", as it were. Turns 
out the majority of crocs [I used only gharials, should have pointed out 
the Nile croc's predilection for wildebeest during the Dry Season] are 
eaters of terrestrials, not fish [bad boy!].

Now, here's Paul's remark:
<I concur with the second opinion. The crocodile-like features 
associated with Baryonyx (festooned mouth margins, differential tooth 
size and elongation of the snout) are features seen in crocs that are 
not fish specialists but generalists. Comparisons with gavials and 
Baryonyx are extremely misleading.> [sniped]

Okay, but I didn't say gavials, I said _gharials_, those long and thin 
snouted crocs with teeth and jaws designed for exclusive fish-predation. 
But you already knew that.

<This snout morphology is more a consequence of housing teeth that vary 
greatly in size (increased pseudoheterodonty equates to increased 
festooning), so the crocodile-like features of Baryonyx are more likely 
to be an adaptional complex associated with housing large 
pseudocaninies. Now the question becomes what Baryonyx was doing with 
pseudocanines?>

<<<Crocodiles, unlike bears, are developed almost to the exclusion of 
all other forms of habitat, to the water, while bears are very varied in 
their place of residence (though all species are excellent swimmers).>>>

<<Modern crocs are, but lets not forget that the crocodylatarsia were 
quite divers in their day. Even today crocs are known to make long 
voyages to other water holes. I say that modern crocs are more developed 
to tackling prey from the water, than to just a simple watery 
existence.>>

This is where I put my foot in my mouth.

<Once again, I concur with the second author. When looking over the 
history of crocodiles, their current exclusive restriction to water is 
misleading. In the past crocs have had a ball of a time on the land, on 
more than one occassion, and don't forget that one of my little buggers 
may even have been climbing trees. Even among living crocodiles, 
Paleosuchus may be spending as much or more time out of water than in.>

I failed to recognized the paleo-crocs, instead of the modern crocs, to 
which I was actually drawing my analogy, only I didn't _say_ so.

<It sounds to me like Baronyx was designed to take animals down from a
riverbank.>

Right, not neccesarily fish, which I said, and was trying to draw a 
conclusion to, without having to say it. I love a good discussion, you 
see, especially when it's couched in terms of an "argument". :-)

<The croc competition for Baryonyx would have been Goniopholis and 
probably Bernissartia, both of which probably did not exceed 2 metres in 
length. Not much of a competition.>

No, and possibly could have been the rare prey for a forty-foot dino 
with a skull only one tenth that long, a great skull-to-body-length 
ratio, also comparable to crocs.

Now, Paul goes on to point out a few of my snout characters:
<<<The snout of *Baryonyx*, though often cited as similar to the 
crocodile snout, is actually a near miss for such an analog, as based on 
several features:
i)   external naris located back from tip, top, and back of snout>>>

<Same as many crocodiles.>

Modern or palaeo? As I understand them, every extant croc has the ext. 
nares located at the tip of the snout, and not only there, but at the 
top, a breathing capability when having most of the head submerged. 
Bary, like *Dilophosaurus*, kept the nose to the side of the snout, just 
moving it posteriorly, which could presume there was something dangerous 
or messy involved with the front end. Like breathing in muck and 
riverbottom slime. Or to keep the tender nose from getting mauled by 
grappling prey.

<<<ii)  orbits located laterally, with some binocular vision>>>

<Same as various extinct crocodiles (Quinkana, Pristichampsus, 
Mekosuchus yadda, yadda, yadda) and some extant crocs (Paleosuchus and 
Osteolaemus).>

Hmmm. I'll have to see who these extant ones are known commonly as 
(could you tell me, Paul?) because as far as I'm aware, the eyes are in 
the position atop the skull rather near to each other for the same 
reason the nose is.

<<<iii) teeth reduced in size towards rear of jaw>>>

<Same as many crocs (depending on the degree)>

Since my conclusion was on the gharial, whose teeth are evenly long 
anteroposteriorly, I would agree.

<<<iv)  anterior teeth forming "piercing" apparatus actually analagous 
to a bear-trap>>>

<OK, you've got me there! (Although Baru and Pallimnarchus spring to 
mind).>

This would actually served to tear apart and hold _large_ prey, and fish 
of smaller size, though I believe a "seive" is a little awkward, it was 
possible.

<I guess what I'm trying to say is that there is more than one reason 
why the snout of Baryonyx resembles that of some crocodiles, but before 
we start guesing why, let's at least get our analogies correct. The 
crocodiles that Baryonyx most resembles are ambush predators of 
terrestrial prey. I would be happy to leave it at that.>

Yes, so would I. I am, I believe, developing a process here to detirmine 
how, or what, may have been Bary's range of food, for it is my opinion 
that he was not an exclusive fish-eater, the whole reason for the 
croc-analogy that I shall have to append. One fish doesn not detirmine 
the entire diet, which was my point on that part.

Keep the comments going!

Jaime A. Headden

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