Open Paleo

Pentaceratops

Osborn, 1923 PEN-ta-SER-a-tops

From Greek 'pente' meaning 'five', 'keras' meaning 'horn', and 'ops' meaning 'face'; translates as 'five-horned face', referring to the five horn-like projections on its skull.

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

Pentaceratops is a genus of herbivorous ceratopsid dinosaur from the late Cretaceous Period of what is now North America. Fossils of this animal were first discovered in 1921, but the genus was named in 1923 when its type species, Pentaceratops sternbergii, was described. Pentaceratops lived around 76-73 million years ago, its remains having been mostly found in the Kirtland Formation in the San Juan Basin in New Mexico. Another species, P. aquilonius, was named by Nick W. Longrich in 2014, but it is debated if it belongs to that genus or a separate taxon. About a dozen skulls and skeletons have been uncovered, so anatomical understanding of Pentaceratops is fairly complete. One exceptionally large specimen later became its own genus, Titanoceratops, due to its more derived morphology, similarities to Triceratops, and lack of unique characteristics shared with Pentaceratops.

Diagnosis

  1. One median nasal horn
  2. Two prominent anteroverted postorbital horns rising directly above orbit center
  3. Two lateral jugal osseous horns projecting downward and backward below orbits
  4. Elongate narrow fontanelle in dermosupraoccipital crest, not circular as in Monoclonius and Torosaurus
  5. Borders of crest moderately sculptured with indentations especially in lower lateral portions

Species

Pentaceratops sternbergii Osborn, 1923

Type species

Named for Charles Hazelius Sternberg, who discovered the holotype skull in the Fruitland Formation of New Mexico in 1922.

Holotype
AMNH 6325 , American Museum of Natural History
Material
Skull and parts of skeleton
Horizon
Fruitland Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Nine miles northeast of Tsaya, New Mexico, United States

References

  1. Osborn, H. F. (1923). A new genus and species of Ceratopsia from New Mexico, Pentaceratops sternbergii. American Museum Novitates 93: 1-3. osborn1923a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026a