Re: BARYONYX

[pwillis@ozemail.com.au (Paul Willis)]

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

Damn it! I'm getting predictable in my old age!

>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!].

The diet of Nile crocodiels (and most crocs for that matter) is a real
mess. They will eat anything, including large amount of carrion and
invertebrates. The point is that long, thin shouted crocs such as gavials
(that well known spelling mistake) improve a crocs chances of catching live
fish but restrict its' ability to tackle more robust things like
wildebeest.

>Okay, but I didn't say gavials, I said _gharials_,

Actually you said neither, you types them. Either spelling is acceptable,
but let's get back to the dabate.

>This is where I put my foot in my mouth.

Are you a Saggitarian too?

>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.

Modern crocs can be pretty misleading when considering matters of croc
potential. Think about what modern birds say about dinosaur diversity and I
think you'll get my point (unless you're Feduccia or something).

><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". :-)

But my point was tht the snout morphology is all about housing large
pseudocanines and has bugger-all to do with riverbanks.

><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.

I hate to sound like a broken record/grouchy old fart, but why bother
saying this? By this argument Baryonyx could have eaten anything that we
know of as a fossil from the same beds that is smaller than it but we have
no evidence that they did and it really tells us nothing useful to
speculate like this. Do we really gain anything by speculating that
Baryonyx ate crocodiles or not?

>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.

It depends on how far forward you want to go. In gavial (gharials, what
ever)they are further forward than say in the Nile croc. the are further
back in alligators and caimen.They do tend to remain on the top of the
snout, even in the dead'ens, but they are not always at the very tip ot the
snout.

>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.

Or perhaps there is an efficiency factor involved or perhaps they are
further back as a consequence of their evolutionary history (with no
adaptive reason) or perhaps they were furtehr back a a sexual selection
feature (I can picture it, can you?). Again, what do whe gain from
speculating when there are so many unknowns in the equation?

><<<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.

Check out Paleosuchus (the Spectacled Caimen) and Osteolaemus (the African
Dwarf Crocodile).

><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.

OK, but all we can say so far is that it did eat a fish (singular). While
the snout features and others may suggest a particular hunting method, we
are none the wiser as to what it was ambushing. Suppose that it spent its
time in the uplands ambushing smurfs, aliens and Godzilla which were never
fossilised because they were always in the wrong place. Our sole specimen
of Baryonyx is one who got lost, found a dead fish, ate it and died of food
poisoning. We would be none the wiser as to its' true diet. So, while we
can talk about how it may have attacked and dispatched prey and we could
suggest some suitable animals that we know of that could be within its'
hunting capacities, let's not get hung up on details that we simply can't
sketch in.



Cheers,

Paul


Dr Paul M.A. Willis
Consulting Vertebrate Palaeontologist
Quinkana Pty Ltd
pwillis@ozemail.com.au

Interesting fact:
Lorne Greene had one of his nipples bitten off by an alligator while he was
host of "Lorne Greene's Wild Kingdom.