Einiosaurus

The nasal horn of *Einiosaurus* is quite unusual in that it curves forward to point towards the ground,‭ ‬something which is reflected in the species name *E.‭ ‬procurvicornis* which translates to English as‭ '‬forward curving horn‭'‬.‭ ‬In young *Einiosaurus* this horn is thought to have started out small,‭ ‬but as the individual grew the horn got larger and more curved until it reached the extremes in what are thought to be adult specimens.‭ ‬This strongly suggested that the curved horn was a sexually selected characteristic that was most developed in the largest and most mature individuals,‭ ‬although it is not certain if males and females shared the same level of development.‭
The curving of this horn is thought to have ultimately evolved to touch upon itself to form the nasal bosses that are present in other related centrosaurine ceratopsians like *Pachyrhinosaurus* and *Achelousaurus*.‭ ‬Ultimately this suggests that *Einiosaurus* was more basal than pachyrhinosaurine members of the Centrosaurinae,‭ ‬yet itself was more advanced than others such as *Centrosaurus*.
As a centrosaurine ceratopsian,‭ *‬Einiosaurus* had a short neck frill compared to the chasmosaurine ceratopsians like *Chasmosaurus*.‭ ‬On the top of this neck frill were two large horns that projected upwards from the top,‭ ‬a feature similar to *Diabloceratops*.‭ ‬Further smaller horns were placed along the outer edges of the neck frill,‭ ‬and although these horns were most probably for the purpose of display,‭ ‬it‭’‬s conceivable that these horns would have offered a little more protection against large tyrannosaurid predators like *Gorgosaurus*,‭ ‬and particularly *Daspletosaurus* which was thought to have been better suited to tackling ceratopsians.‭ ‬Still‭ ‬these frill horns may have best only served to intimidate predators rather than being of practical use,‭ ‬especially as part of a herds group display.
Herding behaviour has been attributed to *Einiosaurus* due to the discovery of a bone bed that yielded the remains of at least fifteen individuals.‭ *‬Einiosaurus* was the only ceratopsian in this bone-bed,‭ ‬and other micro fossils of aquatic molluscs suggest that the ground would have‭ ‬once been underwater.‭ ‬Two theories exist for this occurrence,‭ ‬the first of which is that a herd of *Einiosaurus* clustered around a diminishing water hole during the dry season that was not replenished by rain in time to save the herd.‭ ‬Another and often more widely accepted theory is that the *Einiosaurus* drowned while trying to cross a river,‭ ‬a theory that has been proposed to explain the presence of other ceratopsian dinosaur bone-beds that exist for *Centrosaurus* and *Styracosaurus*.
Droughts and flash floods may have been common problems for *Einiosaurus* to deal with as they seem to have lived in a semi-arid inland environment.‭ ‬Rivers would have not only been one of the few sources of water but also formidable barriers as *Einiosaurus* moved on to fresh grazing areas.‭ ‬The plants of this environment would have been considerably tougher than the lush vegetation of wetland areas,‭ ‬but *Einiosaurus* possessed typical ceratopsian features that allowed it to eat these kinds of plants.‭ ‬The first was a sharp beak that was easily capable of shearing through though and fibrous stems.‭ ‬The mouth had a battery of specialised teeth that were easily capable of grinding tough plant material so that it could be easily digested.
The name *Einiosaurus* is a combination of the Blackfeet‭ '‬eini‭' (‬buffalo‭) ‬and the Ancient Greek‭ '‬saurus‭' (‬lizard‭)‬.