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Re: Oviraptorids as Parrots?





Jaime A. Headden wrote:

Jura (pristichampsus@yahoo.com) wrote:

<Extant alligatorids do maintain some rounded rear teeth. Low and behold, these
are also the only extant crocodylians to show a dietary preference for
turtles.>

 How do you mean, a dietary preference? A preclusion to eat, or a greater
tendency to have a diet consisting of turtles than other animals? If so, what
statistical studies show this?

There aren't a great deal of 'statistical studies' relating to diet in crocodilians. American Alligators do have a reputation for eating turtles. Whether there are any data that suggest turtles form a greater part of their diet than in, say,_ Melanosuchus_ or _Crocodylus porosus_, is an interesting question.


<Morphologically, turtle eaters tend to show rounded, separated and deeply rooted teeth. Whereas molluscivores (the other major shell crushers) show tightly spaced, flat and shallow rooted teeth.>

Broad snouted crocodylids, contrary to the above quotes passages, manage to
eat turtles despite having more or less isodont conical dentition. Both
*Crocodilus porosus* and *C. moreletti* are noted for consuming turtles, and it
has been suggested that this is true of the American croc or caiman (*C.
acutus*), as well as the Nile croc (*C. niloticus*). While most crocodylids
tend to have slender, gharial-style snout morphology, this does not appear to
stop the bigger animals from taking prey they can crush and consume.


I haven't seen _Crocodylus acutus_ referred to as a caiman before. There are three crocodylids that have a slender, 'gharial-style' morphology - _Tomistoma schlegelli_, _Crocodylus cataphractus_, and _Crocodylus johnstoni_. Most of the other extant crocodylids have a 'broader' snout - _Crocodylus acutus_, _C.mindorensis_, _C. moreletti_, C. niloticus_, C. novae-guineae_, C. palustris_, C. porosus_, _C. rhombifer_. As its name suggests, _C. intermedius_ is intermediate between these and the longer snouted forms. This larger group of _Crocodylus_ species do not have _very_ broad snouts - the really broad snouted crocodilians are _Crocodylus siamensis_, _Alligator mississippiensis_, and arguably _Caiman latirostris_ (although the later are short snouted also).

Cheers
Colin



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Colin McHenry
School of Environmental and Life Sciences (Geology)
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