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- Dilophosaurus
- TIME: Early Jurassic
- LOCALITY: North America (Arizona)
- SIZE: 20 ft/6 m long
-
- First discovered in 1942 by an expedition
- from the University of California,
- Dilophosaurus had the typical ceratosaur
- features of a long, slender neck, tail and
- arms, but had a rather heavy head, more like
- that of a carnosaur.The skull of
- Dilophosaurus was unusual for any group. A
- pair of semicircular, bony crests rose
- vertically on either side of the skull.
- Although wafer thin in places, they were
- strengthened by vertical struts of bone. At
- the back of the head, the tip of each crest
- narrowed into a spike.The function of these
- head crests remains a mystery. They have
- never been found actually attached to the
- skull, but lying nearby, so there is a
- certain amount of educated guesswork about
- their position in life. Some paleontologists
- think that they could have been sexual
- display structures, and that only the males
- had them--a theory supported by the fact that
- not all specimens found had the crests.
- Indeed, there were none on the first few
- skeletons unearthed, and the animals were
- thought to have been a species of
- Megalosaurus.The jaws of Dilophosaurus give a
- clue to its lifestyle. The lower jaw was
- strong and full of long, sharp, thin teeth.
- The upper jaw had a cluster of teeth at the
- front, separate from the rest of the
- teeth--rather like the arrangement in the
- jaws of a modern crocodile.So, although
- Dilophosaurus had a large head and strong
- jaws, it probably did not kill its victims by
- biting them; the thin teeth and delicate head
- crests would have been too vulnerable in a
- fight. More likely, this dinosaur caught and
- ripped its prey with the clawed feet and
- hands. Or, like many of its relatives, it
- could have fed on the corpses of creatures
- killed by stronger carnosaurs.
-
- Subject by: Russell Webb
-