Montanoceratops /mɒnˌtænoʊˈsɛrətɒps/ is an extinct genus of small ceratopsian dinosaur that lived approximately 70 million years ago during the latter part of the Cretaceous Period in what is now Montana and Alberta.

Montanoceratops was a small sized, moderately-built, ground-dwelling, quadrupedal herbivore, that could grow up to an estimated 2.5 m (8.2 ft) in length and 170 kg (370 lb) in body mass.

It was collected in 1916 by Barnum Brown and Peter C. Kaisen of the American Museum of Natural History from terrestrial sediments that were deposited during the Maastrichtian stages of the Cretaceous period, approximately 70 million years ago.

This specimen was collected by Barnum Brown in 1910, from terrestrial sediments on the east bank of the Red Deer River near Tolman Ferry at the Horseshoe Canyon Formation in Alberta, Canada.

[6] Montanoceratops was a typical primitive ceratopsian in many respects, distinguished from the later species by the presence of claws, rather than hooves, and by having teeth in its upper jaw, rather than a toothless beak.

Liaoceratops Aquilops Yamaceratops Auroraceratops Archaeoceratops Helioceratops Koreaceratops Asiaceratops Cerasinops Ischioceratops Montanoceratops Prenoceratops Leptoceratops Udanoceratops Zhuchengceratops Gryphoceratops Unescoceratops Coronosauria An unusual feature was the presence of tall spines on the bones of the tail.

Evidence of this injury is also present in the outer surface of the left ischium, where there is a large, irregularly shaped growth of bone that has formed across a healed fracture.

[15][16] Montanoceratops shared the paleoenvironment of the St. Mary River Formation with other dinosaurs, such as the ceratopsians Anchiceratops and Pachyrhinosaurus canadensis, the armored nodosaur Edmontonia longiceps, the duckbilled hadrosaur Edmontosaurus regalis, species of the troodontids Saurornitholestes and Troodon, and the tyrannosaurid Albertosaurus, which was likely the apex predator in its ecosystem.

[17] Vertebrates present in the St. Mary River Formation at the time of Montanoceratops included the actinopterygian fishes Amia fragosa, Lepisosteus, Belonostomus longirostris, Paralbula casei, and Platacodon nanus, the mosasaur Plioplatecarpus, and the diapsid reptile Champsosaurus.

[citation needed] A fair number of mammals lived in this region, which included Turgidodon russelli, Didelphodon, Leptalestes, Cimolodon nitidus, and Paracimexomys propriscus.

This included dinosaurs such as the ankylosaurid Anodontosaurus lambei, the nodosaurid Edmontonia longiceps, the maniraptorans Atrociraptor marshalli, Epichirostenotes curriei, Richardoestesia gilmorei, Richardoestesia isosceles, the troodontids Paronychodon lacustris and Albertavenator curriei, the alvarezsaurid theropod Albertonykus borealis, the ornithomimids Dromiceiomimus brevitertius, Ornithomimus edmontonicus, and Struthiomimus altus, the pachycephalosaurid Sphaerotholus edmontonensis, the ornithopod Parksosaurus warreni, the hadrosaurids Edmontosaurus regalis, Hypacrosaurus altispinus, and Saurolophus osborni, the ceratopsians Anchiceratops ornatus, Arrhinoceratops brachyops, Eotriceratops xerinsularis, Pachyrhinosaurus canadensis, and the tyrannosaurid Albertosaurus sarcophagus, which was the apex predator of this paleoenvironment.

A study by Quinney et al. (2013) however, showed that the decline in turtle diversity, which was previously attributed to climate, coincided instead with changes in soil drainage conditions, and was limited by aridity, landscape instability, and migratory barriers.