Stygimoloch

stygimoloch
Stygimoloch (Wikimedia Commons).

Name:

Stygimoloch (Greek for "horned demon from the river Styx"); pronounced STIH-jih-MOE-lock

Habitat:

Plains of North America

Historical Period:

Late Cretaceous (70-65 million years ago)

Size and Weight:

About 10 feet long and 200 pounds

Diet:

Plants

Distinguishing Characteristics:

Moderate size; unusually large head with bony protuberances

 

About Stygimoloch

Stygimoloch (the genus and species name of which, S. spinifer, can be loosely translated as "horned demon from the river of death") wasn't nearly as terrifying as its name implies.

A type of pachycephalosaur, or bone-headed dinosaur, this plant-eater was actually fairly lightweight, about the size of a fully grown human being. The reason for its intimidating name is that its bizarrely ornamented skull evokes the Christian conception of the devil--all horns and scales, with the slightest hint of an evil leer if you look at the fossil specimen just right.

Why did Stygimoloch have such prominent horns? As with other pachycephalosaurs, it's believed that this was a sexual adaptation--males of the species head-butted each other for the right to mate with females, and bigger horns provided a valuable edge during rutting season. (Another, less convincing theory is that Stygimoloch used its gnarly noggin to butt away the flanks of ravenous theropods). Apart from these displays of dinosaur machismo, though, Stygimoloch was probably fairly harmless, feasting on vegetation and leaving the other dinosaurs of its late Cretaceous habit (and small, cowering mammals) alone.

Within the past few years, there has been an intriguing development on the Stygimoloch front: according to new research, the skulls of juvenile pachycephalosaurs changed drastically as they aged, much more so than paleontologists had previously suspected. Long story short, it turns out that what scientists call Stygimoloch may in fact have been a juvenile Pachycephalosaurus, and the same reasoning may well apply to another famous thick-headed dinosaur, Dracorex hogwartsia, named after the Harry Potter movies.

(This growth-stage theory applies to other dinosaurs as well: for example, the ceratopsian we call Torosaurus may simply have been an unusually elderly Triceratops individual.)