Open Paleo

Medusaceratops

Ryan et al., 2010 muh-DOO-suh-SEH-ruh-tops

From Medusa, the snake-haired monster of Greek mythology whose gaze turned men to stone, referencing the large snake-like frill spikes, combined with Latinized Greek 'ceratops' meaning 'horned face'.

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Medusaceratops is an extinct genus of centrosaurine ceratopsian dinosaur known from the Late Cretaceous Judith River Formation (middle Campanian stage) of Montana, northern United States. It contains a single species, Medusaceratops lokii.

Diagnosis

  1. Only three epiparietals (P1-3) on lateral parietal ramus, unlike centrosaurines with seven loci
  2. Large, thick, hook-like P1 epiparietal at caudolateral margin, dorsoventrally depressed and rostrally curved
  3. P2 process lobe-shaped and rugose with hook-shaped rostral margin, smaller than P1
  4. P3 process small, triangular, depressed, unmodified, positioned at parietal-squamosal contact

Species

Medusaceratops lokii Ryan et al., 2010

Type species

Named for Loki, the troublemaking god of Norse mythology, in reference to the years of taxonomic confusion that surrounded the Mansfield Bonebed material before it was formally described as its own genus.

Holotype
WDC-DJR-001 , Wyoming Dinosaur Center
Material
Partial right lateral parietal ramus with complete adult-sized morphology, including large dorsoventrally depressed hooked P1 epiparietal, P2 and P3 processes
Horizon
McClelland Ferry Member, Judith River Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Mansfield Bonebed, Kennedy Coulee, Montana, United States

References

  1. Ryan, M. J.; Russell, A. P.; Hartman, S. (2010). A new chasmosaurine ceratopsid from the Judith River Formation, Montana. New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium (Ryan, M. J.; Chinnery-Allgeier, B. J.; Eberth, D. A., eds.) 181-188. Indiana University Press, Bloomington. ryan2010a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the mass and hip height estimates, and the appearance features.

    jones2026a
  3. Chiba, K.; Ryan, M. J.; Fanti, F.; Loewen, M. A.; Evans, D. C. (2018). New material and systematic re-evaluation of Medusaceratops lokii (Dinosauria, Ceratopsidae) from the Judith River Formation (Campanian, Montana). Journal of Paleontology 92(2): 272-288. Cambridge University Press. doi:10.1017/jpa.2017.62

    Places the holotype's bonebed in the McClelland Ferry Member.

    chiba2018a