Monoclonius
"single sprout"
Type species Monoclonius crassus
- Lived
- 84 to 72 million years ago, Late Cretaceous
- Diet
- Herbivore
- Group
- Ceratopsians, Ceratopsidae
- Found in
- Canada and United States
- Named by
- Cope 1876
Where its fossils were found
The evidence
Today
80 million years ago
Habitat
River plains in western North America supported horned dinosaurs and duckbills. Other dinosaurs from these rocks include Daspletosaurus, Stegoceras and Corythosaurus.
Field notes
About Monoclonius
What it was like
Monoclonius was a horned dinosaur with a large nose horn and a frill. The fossils are pieces of frills and skulls, and many scientists now think they are not enough to tell it apart from relatives such as Centrosaurus.
Its world
It lived in the Late Cretaceous, in western North America. Its fossils come from Montana and Alberta, where it shared the land with the tyrannosaurs Daspletosaurus and Gorgosaurus, the dome-headed Stegoceras and the duckbill Corythosaurus.
How it was found
Cope named Monoclonius in 1876, making it one of the first horned dinosaurs ever named. The type species is Monoclonius crassus. Because the fossils are so incomplete, most scientists treat the name as doubtful.
Field gallery
More views of Monoclonius
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 Monoclonius.
The evidence
The science behind Monoclonius
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- The skull frill includes a thin bony sheet with large openings.
- Frill bones assigned to Monoclonius have the long-grained surface texture of growing horned dinosaurs.
Borrowed from relatives
- The stocky body, beak and walking posture are restored from better-known horned dinosaurs such as Centrosaurus.
- Centrosaurus provides a comparison for how horns and frill ornaments changed as these animals grew.
Still unknown
- Whether the original fossils belong to a distinct genus or a growing member of another horned dinosaur genus.
- The adult shape of the horns and frill belonging to the original animal.
- Its color.
Discovery timeline
- 1876Named itCope
- 1997Growing upSAMPSON, RYAN & TANKE
- 2014Close relativeFrederickson & Tumarkin-Deratzian
Key papers
The research behind what we know of Monoclonius
Named it
Named Monoclonius crassus from fragmentary dinosaur remains collected in Montana.
Descriptions of some vertebrate remains from the Fort Union Beds of Montana. Proceedings of the Academy of Natural Sciences of Philadelphia 28: 248-261
No link available
Growing up
Found that distinctive horns and frill ornaments developed late in growth, and treated Monoclonius crassus as a doubtful name based on immature fossils.
Craniofacial ontogeny in centrosaurine dinosaurs (Ornithischia: Ceratopsidae): taxonomic and behavioral implications. Zoological Journal of the Linnean Society 121: 293-337
Read the paper : Craniofacial ontogeny in centrosaurine dinosaurs (Ornithischia: Ceratopsidae): taxonomic and behavioral implications (opens in a new tab)Close relative
Tracked changes in Centrosaurus skulls as they grew, showing why horn shape alone is a poor guide to maturity.
Craniofacial ontogeny inCentrosaurus apertus. PeerJ 2: e252
Read the paper : Craniofacial ontogeny inCentrosaurus apertus (opens in a new tab)
Close relatives
Other members of Ceratopsidae
Sources: Wikidata