Cryolophosaurus, as a holotype fossil, consists of a partial skeleton that was discovered with a complete skull (cranium and face plus lower jaw and teeth). As far as paleontology goes that is somewhat rare, but it does happen from time to time and the dinosaurs (or other fossil animals) we find as mostly whole are often bewildering and exciting. Obviously, I think, Cryolophosaurus was a very exciting find for a number of reasons: the state of preservation, as just noted; that it was discovered in Antarctica; and the always talked about head crest adorning its cranium. The head of Cryolophosaurus is amazing all by itself though, even without the crest. Approximately 65 cm (26 in) long, Cryolophosaurus' head was a little less than 1/3 the length of the largest Tyrannosaurus skull (1.52 m; 5 ft). The skull was also considerably narrow and tall, from top to bottom, as well. Running from the nasal area to the side-to-side crest is a ridge that runs courses along the midline until it widens and meets with the perpendicular crest that is so iconic of the dinosaur. The purpose of the crest has been discussed many different times in many different ways. It has been considered a fighting implement by some and a social ornamentation by others. Many have hypothesized that the crest was used for mating displays. Much consideration has been given to other characteristics of Cryolophosaurus as well. The crest as well as a large group of other characteristics have led to many different phylogenetic hypotheses for Cryolophosaurus. Rather than revisiting all of these, we can note that currently Cryolophosaurus appears to be nestled in a spot in the family tree that is a little more advanced than Dilophosaurs and Ceratosaurs, but more primitive than Allosaurs and Coelurosaurs (the group that includes Tyrannosaurus as well as ornithomimids and maniraptorans).
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