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DEINOSUCHUS vs. TYRANNOSAUR?



Hello all.

I heard recently from Canadian ethologist Tim Isles that there is now some
definite fossil evidence showing that _Deinosuchus_ was eating (and, by
implication, preying on) young and adult specimens of _Albertasaurus_/
_Gorgosaurus_ (probably refers to _G. libratus_). Apparently this was announced
in a recent ish of _Earth_ - I didn't catch it and it's not in the current
issue. Anyone know any more on this?

A bit ironic is this news, as only recently I was informing people that, though
it is restored so often as a predator of dinosaurs, there is actually no reason
to believe that _Deinosuchus_ was. An abstract in _JVP_ 16 - sorry, I forget by
who - tells of evidence gleaned from the shells of Cretaceous turtles: these
animals were apparently prey to _Deinosuchus_, and maybe it was a chelonivore.
Chelonivory is actually moderately common in crocodylians. It appears to be
pretty much the norm for Upper Cretaceous alligatorids (e.g. _Montanachampsa_
and _Brachychampsa_) and has been evolved several times in Tertiary-Recent taxa.
_Purrasaurus_ (Campbell and Frailey, 1990) was apparently eating big freshwater
turtles, as were some of the '_Leidyosuchus_' species.

You don't have to be ultra-specialised to be a chelonivore though, as some
Jaguars (_Panthera onca_) feed a great deal on freshwater turtles. They wear
down and break their teeth on the shells. Jaguars employ two modes of turtle
attack, used depending on turtle species. For turtles with round carapaces, they
bite through the top and eat down to the plastron. For flat-shelled turtles,
they bite into the 'corners' where the legs are, and leave the middle.

There is a bit in the _current_ _Earth_ about Cretaceous sharks of some kind
(cretoxyrhinchids I think) scavenging on the carcass of a juvenile hadrosaur.

One more thing: when's the next ish of _Dinosaur Discoveries_ due out?

"Enough talk babe, time for my patented gyro-tongue action"

Yikes, day 9.

DARREN NAISH