Arrhinoceratops
"no nose horn face"
- Lived
- 84 to 66 million years ago, Late Cretaceous
- Diet
- Herbivore
- Length
- about 6 m (20 ft)
- Group
- Ceratopsians, Ceratopsidae
- Found in
- Canada
- Named by
- Parks 1925
Size comparison
To scale
Scale in metersOutline: typical ceratopsian shape
Where its fossils were found
The evidence
Today
75 million years ago
Habitat
Rivers, floodplains and swamps formed the landscape preserved in the Horseshoe Canyon Formation, with conifers and ferns among the plants. Other dinosaurs included Albertosaurus, Edmontosaurus and Saurolophus.
Field notes
About Arrhinoceratops
What it was like
Arrhinoceratops was a horned dinosaur about 6 meters (20 feet) long, related to Triceratops. It had two long brow horns, a short nose horn and a broad frill with two openings.
Its name means it had no nose horn, but that was a mistake: the horn is there, just short.
Its world
It lived in the Late Cretaceous, in what is now Alberta, Canada. It comes from the Horseshoe Canyon Formation, where it shared the land with the tyrannosaur Albertosaurus, the duckbills Edmontosaurus and Saurolophus, and the ostrich-like Ornithomimus and Struthiomimus.
How it was found
Parks named Arrhinoceratops in 1925, from a crushed skull.
Field gallery
More views of Arrhinoceratops
Scenes reconstructed from the available fossil evidence.
Lived alongside
Found in the same rock formations
A rock formation can hold fossils laid down millions of years apart, so not every animal here met Arrhinoceratops.
The evidence
The science behind Arrhinoceratops
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- Skulls show long brow horns, a short nose horn and a broad, roughly rectangular frill.
- A more complete find includes the lower jaw, joined neck vertebrae and part of a forelimb.
- The lower jaw has a distinctive ridge along its outer surface.
Borrowed from relatives
- Vagaceratops helps restore the missing trunk and limbs as a sturdy, four-legged body.
- Triceratops provides a comparison for the missing hands, with strong inner fingers and smaller outer fingers.
Still unknown
- Its skin texture and color.
- The full proportions of its body and tail.
- How it used its horns and frill in encounters with other animals.
Often drawn wrong
- Its name can lead to a hornless nose, but it had a short nose horn.
- The openings in the bony frill were covered by living tissue, rather than left as holes through the neck shield.
Discovery timeline
- 1925Named itParks
- 2014New findMallon et al.
- 2015Growing upMallon, Ryan & Campbell
Key papers
The research behind what we know of Arrhinoceratops
Named it
Named Arrhinoceratops from a crushed skull with long brow horns and a broad frill.
Arrhinoceratops brachyops, a new genus and species of Ceratopsia from the Edmonton Formation of Alberta. University of Toronto Studies, Geology Series 19: 1-15
No link available
New find
Described another skull with neck and forelimb bones, revealing distinctive features of the nose horn and lower jaw.
New information on the rare horned dinosaurArrhinoceratops brachyops(Ornithischia: Ceratopsidae) from the Upper Cretaceous of Alberta, Canada. Canadian Journal of Earth Sciences 51: 618-634
Read the paper : New information on the rare horned dinosaurArrhinoceratops brachyops(Ornithischia: Ceratopsidae) from the Upper Cretaceous of Alberta, Canada (opens in a new tab)Growing up
Compared young and older skulls, showing that brow horns lengthened and turned forward while the frill ornaments flattened as the animal grew.
Skull ontogeny inArrhinoceratops brachyops(Ornithischia: Ceratopsidae) and other horned dinosaurs. Zoological Journal of the Linnean Society 175: 910-929
Read the paper : Skull ontogeny inArrhinoceratops brachyops(Ornithischia: Ceratopsidae) and other horned dinosaurs (opens in a new tab)
Close relatives
Other members of Ceratopsidae
Sources: Wikidata