I agree - with its size and splayed legs, I don't think its Dex should be any higher than 8 or 9.
Edit: Here's a preliminary stat-block I've come up with:
Edit 2: Oops, missed Shade's post, I'll just leave the flavor text.
This bull-sized creature is built like a barrel. Its thick body is supported by stout, splayed legs, and a short tail lashes behind it. Its most distinctive feature, however, is its head: one the sides of the face and above the eyes, it has horn-like projections, causing it to resemble a reptilian moose.
Estemmenosuchus is a dinocephalian, a type of primitive therapsid (“mammal-like reptile”). Like some other dinocephalians, it has bony ornamentation of the head, leading adventurers to refer to it as the “crowned crocodile.” The estemmenosuchus' ornamentation resembles the antlers of a large deer. Estemmenosuchuses use these antler-like projections to compete by head-butting and pushing.
An estemmenosuchus is 10 feet long and weighs one ton.
Combat
Estemmenosuchuses, especially males, are aggressive animals and will charge with head lowered into anything they deem to be a potential threat (basically any Medium or larger creature). In addition to their headgear, they have large canine teeth, making bites from estemmenosuchuses potentially deadly.
Do we want to give it any special attacks, like deadly charge? How about ferocity?
Dangit, my USB thumb drive just stopped working AGAIN, so I lost all my work on my dinosaur book project since I backed it up on December 21st >_< I hope that either it'll start working again miraculously or my dad can somehow recover it....even if neither of those happen, most of the stuff I lost was converted creatures from this thread, so it shouldn't be too hard to start over...