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RE: Terrestrial crocodiles

>>Were any of these bipedal like theropods?
>Probably not.
>Interesting he should ask that. A new article by Rossmann describes
>Pristichampsus rolliantii as being bipedal, or partially. The scutes
>interlock and stiffen the back (according to Rossmann, I think, it's all in
>German) and the claws are more like a bipedal animal than not.

I've read this article, and I don't completely buy it.  The claws are more
like a bipedal animal on the forelimb as well as on the hindlimb - so I
suppose that means it was handwalking?

I think Torsten is correct about Pristichampsus being more terrestrial -
it's the bipedal bit I'm skeptical about.

>Rossmann, Torsten, 2000. Studies on Cenozoic crocodilies: 5. Biomechanical
>investigation on the postcranial skeleton of the Palaeogene crocodile
>Pristichampsus rollinatii (Eusuchia: Pristichampsidae). N. Jb. Geol.
>Palaont. Abh. 217, (3): 289-300.
>(Full filling a subtle request)
>As far as totally terrestrial crocodilomorphs, why not? Notosuchians (some
>at least) lived in burrows. Sebosuchians and Pristichampsians have taller
>skulls than their aquatic cousins.

Yes, but so do some blunt-snouted crocs, including Paleosuchus.
Paleosuchus is certainly more terrestrial than other living crocs (except
maybe Osteolaemus), but also spends quite a lot of time in flowing water.
Snout depth probably has more to do with jaw mechanics (and diet) than with
whether an animal is on land or not.

Several living crocs also make burrows - Chinese alligators (Alligator
sinensis, which will probably be extinct in 50 years in the wild), several
species of Crocodylus, etc.  None of these are completely terrestrial.
There is peer-reviewed literature out there on this.

I am not opposed to the idea of terrestrial crocodyliforms; what makes me
uncomfortable is the assertion that they were, given that some lines of
evidence are not uniquely found in crocs thought to be terrestrial.


Christopher A. Brochu
Department of Geology
Field Museum
1400 S. Lake Shore Drive
Chicago, IL 60605

phone 312-665-7633
fax 312-665-7641
electronic cbrochu@fmppr.fmnh.org