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The horniest of the horned dinosaurs (ceratopsians), Pentaceratops roamed and roared around what is now New Mexico near the end of the Cretaceous period. The biggest fossilized specimen of this ponderous beast yet found was about 6.8 meters long and 2.5 meters high at the hips. This skeleton's skull alone was an enormous 2.3 meters long, and an even bigger skull, almost 3 meters, was dug up later without the remainder of its skeleton. This second skull may be the largest ever discovered for a terrestrial animal.

Pentaceratops was built more compactly than most of its relatives, with a stocky body and proportionally shorter tail than Chasmosaurus or Triceratops. The hind legs were longer than the front legs, with the dinosaur's body mass centered far forward of its hips. And if you've already guessed from its name how many horns it had (five!), you win...well, nothing. But it turns out that two of those horns weren't really horns after all.

Like the rest of the ceratopsians, Pentaceratops lumbered around on all fours and chowed down on a herbivorous diet with its powerful, parrot-like beak. What really set this genus apart from the rest of the "horned faces" was the enormity and distinctive shape of its skull. The frill of bone at the rear of a Pentaceratops skull reached lengths of up to 1.5 meters, but it wasn't particularly backswept, tending more to the vertical than usual. Two large horns grew above the eyes and a smaller one on the nose, and the two additional "horns," oriented somewhat sideward, were really outgrowths of the cheekbones.

Two species, Pentaceratops sternbergi and Pentaceratops fenestratus, were named in the 1920's, but their differences may not be significant enough to warrant separate classification. All specimens, regardless of species, were found in the same region of New Mexico.

Order: Ornithischia
Suborder: Marginocephalia
Infraorder: Ceratopsia
Micro-order: Neoceratopsia
Family: Ceratopsidae

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