Mean atmospheric O2
Geologic Time Scale
A six ton, 27-foot-long ceratopsid dinosaur of the genus Pentaceratops wanders a Cretaceous forest 75 million years ago in what is today New Mexico. With long horns and an enormous frill, Pentaceratops' skull was up to 10 feet long--the largest known skull for a land vertebrate.
Like the better known Triceratops, Pentaceratops was an especially large ceratopsid, a family of four-legged plant-eating dinosaurs characterized by beaks, rows of shearing teeth in the back of the jaw, and elaborate horns and frills. While they resemble defensive shields, the frills are in fact relatively fragile, suggesting that they may have served a purpose other than protecting against a brute force attack. One possibility is that the frills were employed as visual displays in order to intimidate rivals and attract the opposite sex. While no color pigmentation has been preserved in the fossil remains of ceratopsids, it's not unreasonable to suggest that they may have been very colorful, like many reptiles and birds today.
Copyright © Walter B. Myers. All rights reserved.
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