Open Paleo

Arrhinoceratops

Parks, 1925 a-RIEN-o-SER-a-tops

From Ancient Greek a-/alpha privative (ἀ-) meaning 'no/without' + rhis (ῥίς) meaning 'nose' + keras (κέρας) meaning 'horn' + ops (ὤψ) meaning 'face'; overall meaning 'no nose-horn face'.

83.6–66.0 million years ago Campanian–Maastrichtian, Late Cretaceous
Late Cretaceous stages

Arrhinoceratops is a genus of herbivorous ceratopsian dinosaur. The name was coined as its original describer concluded it was special because the nose-horn was not a separate bone, however further analysis revealed this was based on a misunderstanding. It lived during the latest Campanian/earliest Maastrichtian stage of the Late Cretaceous, predating its famous relative Triceratops by a few million years, although it was contemporary with Anchiceratops. Its remains have been found in Canada.

Diagnosis

  1. Nasal horn core absent; nasal bone forms only a sharp longitudinal ridge with fine rugosities, without horn core or epinasal
  2. Supraorbital horn cores large, approximately circular in cross section, directed upward, outward, and forward
  3. Facial region unusually short relative to crest length (ratio ~0.52)
  4. Crest strikingly subquadrate in outline and very flat posteriorly, with no epoccipitals on margin
  5. Anterior process of jugal unusually long, overlapping the maxillary extensively and making suture with nasal unusually short
  6. Lower temporal arcade remarkably bar-like, producing a low isosceles-triangular lateral temporal fossa

Species

Arrhinoceratops brachyops Parks, 1925

Type species

Means 'short-faced', derived from the Greek brachys, meaning 'short'.

Holotype
ROM 796 , Royal Ontario Museum
Material
Nearly complete cranium (without lower jaw), right side in better condition; found in vertical position in white sandstone 125 feet above river level, Red Deer River opposite Neill's ranch
Horizon
Horseshoe Canyon Formation, Campanian–Maastrichtian, Late Cretaceous , 83.6–66.0 million years ago
Locality
Neill's Ranch, Red Deer River, Alberta, Canada

References

  1. Parks, W. A. (1925). Arrhinoceratops brachyops, a new genus and species of Ceratopsia from the Edmonton Formation of Alberta. University of Toronto Studies, Geology Series 19: 1-15. parks1925a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the appearance features.

    jones2026a