Information about Stygimoloch

Stygimoloch
Conservation status
Extinct (fossil)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Superorder: Dinosauria Order: Ornithischia Suborder: Marginocephalia Infraorder: Pachycephalosauria Family: Pachycephalosauridae Genus: Stygimoloch Galton & Sues, 1983
Species
S. spinifer Galton & Sues, 1983

Stygimoloch (meaning "horned devil from the river of death") was a pachycephalosaurid dinosaur from the end of the Cretaceous period, roughly 65 million years ago. It is currently known from the Hell Creek Formation and Lance Formation of the Western Interior, where it lived alongside Tyrannosaurus and Triceratops.

It is a relatively large pachycephalosaur, with the skull being about eighteen inches long. Among North American pachycephalosaurs, only Pachycephalosaurus is larger. Unlike other pachycephalosaurs, the domed skull is relatively small, slightly flattened from side to side, and pear-shaped; even when isolated this unusual dome can easily be distinguished from the broader, larger domes of Pachycephalosaurus.

While the dome is reduced in size, the ornamentation over the skull is more elaborate than in any other pachycephalosaur. Short, conical hornlets covered the nose, and the back corners of the skull bore an enormous pair of massive, backward-pointing spikes, up to two inches in diameter and six inches long; these are surrounded by 2-3 smaller spikes. The function of this unusual ornamentation is unknown. Even if other pachycephalosaurs did butt heads (which is a subject of continuing debate), the small dome of Stygimoloch suggests that this behavior was not as important. Instead, the skull ornament might have functioned for display, may have been used for self-defense, or perhaps were locked together and used in shoving matches, like the horns of deer. More likely, however, is that the squamosal horns were used to inflict pain during flank-butting. ^[1]

The pachycephalosaur Dracorex may actually be an individual of Stygimoloch in which the dome and horns are not well-developed, either because the animal was a juvenile or a female.

References