Species of ornithischian dinosaur

Stygimoloch was a plant-eating dinosaur that had bony spikes and knobs on its skull. This bipedal dinosaur lived during the late Cretaceous period, about 70 million to 66 million years ago.

Temporal range: Upper Cretaceous
70–66 mya
Reconstructed skull at the Museum für Naturkunde, Berlin
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Suborder: Pachycephalosauria
Family: Pachycephalosauridae
Genus: Stygimoloch
Galton & Sues, 1983
S. spinifer
Binomial name
Stygimoloch spinifer
Galton & Sues, 1983

Like other pachycephalosaurids, Stygimoloch was a bipedal herbivore with an extremely thick skull roof. It had long hindlimbs and small forelimbs. Stygimoloch probably head-butted as a defense and in rivalry.

22% of all domes examined had lesions suggesting osteomyelitis. This is an infection of the bone resulting from trauma. So pachycephalosaurid domes were probably used in intra-species combat.[1]

Stygimoloch fossils were first discovered in North America, in Montana and Wisconsin. The first was discovered in Hell Creek, Montana and was named in 1983 by Peter M. Galton, a British paleontologist and Hans-Dieter Sues, a German paleontologist.


  1. Peterson, JE; Dischler, C; Longrich, NR (2013). "Distributions of cranial pathologies provide evidence for head-butting in dome-headed dinosaurs (Pachycephalosauridae)". PLOS ONE. 8 (7): e68620. Bibcode:2013PLoSO...868620P. doi:10.1371/journal.pone.0068620. PMC 3712952. PMID 23874691.