Open Paleo

Kosmoceratops

Sampson et al., 2010 KOZ-mo-SEH-ruh-tops /ˌkɒzməˈsɛrətɒps/

From Greek kosmos (ornate/decorated) combined with ceratops (horned face); meaning "ornate horned face", referring to the elaborate skull ornamentation

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

Kosmoceratops is a genus of ceratopsid dinosaur that lived in North America about 76-75.9 million years ago during the Late Cretaceous period. Specimens were discovered in Utah in the Kaiparowits Formation of the Grand Staircase-Escalante National Monument in 2006 and 2007, including an adult skull and postcranial skeleton and partial subadults. In 2010, the adult was made the holotype of the new genus and species Kosmoceratops richardsoni; the generic name means "ornate horned face", and the specific name honors Scott Richardson, who found the specimens. The find was part of a spate of ceratopsian discoveries in the early 21st century, and Kosmoceratops was considered significant due to its elaborate skull ornamentation.

Diagnosis

  1. Internal naris rostrocaudally abbreviated and caudodorsally inclined
  2. Nasal horncore transversely constricted, long-based, blade-like with flattened distal portion
  3. Supraorbital horncores dorsolaterally directed proximally with ventral curvature distally tapering to point
  4. Parietosquamosal frill relatively short and broad (max width ~2x max length) with small caudally positioned parietal fenestrae
  5. Ten well developed hook-like processes on caudal frill margin (three epiparietals, one epiparietosquamosal, one episquamosal per side)
  6. Most ornate skull of any known dinosaur with 15 well developed horns or horn-like structures

Species

Kosmoceratops richardsoni Sampson et al., 2010

Type species

Named in honor of Scott Richardson, who found the specimens.

Holotype
UMNH VP 17000 , Utah Museum of Natural History
Material
Nearly complete skull
Horizon
Kaiparowits Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
UMNH VP locality 890, Utah, United States

Notable specimens

  • UMNH VP 16878

    Utah Museum of Natural History ontogeny

    A disarticulated subadult skull about half the size of the adult, missing the premaxilla, rostral, and predentary bones. It has the same number and pattern of epiossifications as the adult holotype, distinguishing the subadult growth stage of Kosmoceratops from that of Utahceratops.

    Loewen et al. (2013)

  • UMNH VP 21339

    Utah Museum of Natural History physiology

    A disarticulated subadult or adult whose femur was histologically sampled, showing sustained rapid growth and supporting an elevated, endothermic metabolism in Kosmoceratops. The analysis determined the specimen was subadult to adult, ruling out that it represented an immature Vagaceratops.

    Levitt (2013)

References

  1. Sampson, S. D.; Loewen, M. A.; Farke, A. A.; Roberts, E. M.; Forster, C. A.; Smith, J. A.; Titus, A. L. (2010). New Horned Dinosaurs from Utah Provide Evidence for Intracontinental Dinosaur Endemism. PLoS ONE 5(9): e12292. Public Library of Science (PLoS). doi:10.1371/journal.pone.0012292 sampson2010a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

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

    jones2026a
  3. Loewen, M.; Farke, A. A.; Sampson, S. D.; Getty, M. A.; Lund, E. K.; O'Connor, P. M. (2013). Ceratopsid dinosaurs from the Grand Staircase of Southern Utah. At the Top of the Grand Staircase: The Late Cretaceous of Southern Utah 488-503. Indiana University Press, Bloomington. loewen2013b
  4. Levitt, C. G. (2013). Bone histology and growth of chasmosaurine ceratopsid dinosaurs from the late Campanian Kaiparowits Formation, Southern Utah. Masters thesis, University of Utah.

    Master's thesis.

    levitt2013a