Top 10 Ceratopsians
Ceratopsia or Ceratopia is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. Below you’ll find 10 Ceratopsians that were subjects for research by paleontologists.
Triceratops would have lived alongside other types of ceratopsian dinosaurs, though not the previously mentioned Styracosaurus as it is often depicted since this genus lived much earlier in Campanian stage of the Cretaceous, whereas Triceratops is late Maastrichtian. In 2010 it was claimed that another genus of ceratopsian named Torosaurus was not only a synonym to Triceratops, but actually represented the true adult form. Torosaurus is noted for having a very similar body and horn arrangement to Triceratops, but a much larger neck frill with openings, whereas the frill on known Triceratops is relatively short and solid. Others have not been convinced however noting that a lack of known Torosaurus individuals at different ages makes a comparison to Triceratops difficult to establish. Differences in the skulls of Triceratops and Torosaurus are also pointed out, as well as to date there is no known occurrence of holes appearing in frills of adult ceratopsians when sub adults and even juveniles do not have them (holes in the frill usually start developing very early on in life). Either Triceratops and Torosaurus are indeed separate, or Triceratops would be the first known ceratopsian where frill holes suddenly appear upon adulthood.
Closely related to Centrosaurus, Styracosaurus had one of the most distinctive heads of any ceratopsian, at least until the recent discovery of bizarre North American genera like Kosmoceratops and Mojoceratops. As with all ceratopsians, the horns and frill of Styracosaurus likely evolved as sexually selected characteristics: males with bigger, more elaborate, more visible headgear had a better chance of intimidating their rivals in the herd and attracting available females during mating season.
Protoceratops was that rare beast of the Mesozoic Era, a mid-sized ceratopsian—not tiny like its predecessors (such as the five-pound Aquilops), or four or five tons like its North American successors, but a pig-sized 400 or 500 pounds. As such, this made the central Asian Protoceratops an ideal prey animal for the contemporary Velociraptor. In fact, paleontologists have identified a famous fossil of a Velociraptor locked in combat with a Protoceratops, before both dinosaurs were buried by a sudden sandstorm.
For decades, Psittacosaurus (the “parrot lizard”) was one of the earliest identified ceratopsians, until the recent discovery of a handful of eastern Asian genera that predated this dinosaur by millions of years. As befitting a ceratopsian that lived during the early to middle Cretaceous period, Psittacosaurus lacked any significant horn or frill, to the extent that it took a while for paleontologists to identify it as a true ceratopsian and not an ornithischian dinosaur.
Achelousaurus is an interesting genus as it seems to represent a transitional form linking genera like Einiosaurus with genera like Pachyrhinosaurus. This has helped portray a line with Einiosaurus known from the Campanian stage, and Pachyrhinosaurus known from roughly the late Campanian/early Maastrichtian, it would seem that as the horns of genera like Einiosaurus curved over they eventually formed the large mass on the snouts of genera like Pachyrhinosaurus. This is yet a further indication that the horns of ceratopsian dinosaurs were less for defence and more for display.
Zuniceratops makes the list for being the earliest occurrence of a horned ceratopsian in North America. This has raised fresh questions over whether horned ceratopsians evolved in North America or Asia first, though while we might have an idea, in all likelihood the early horned ceratopsians probably radiated out across both continents and back again several times. Zuniceratops was named in honour of the Zuni tribe.
You might recognize Pachyrhinosaurus (the “thick-nosed lizard”) as the star of the late, unlamented Walking with Dinosaurs: The 3D Movie. Pachyrhinosaurus was one of the few late Cretaceous ceratopsians to lack a horn on its snout; all it had were two small, ornamental horns on either side of its enormous frill.
The main group of ceratopsian dinosaurs that are separate from the centrosaurines are the chasmosaurines, of which Chasmosaurus is the type genus. Chasmosaurus and relative genera are noted for having less elaborate horn displays than centrosaurines, but at the same time they had far larger and more elaborate neck frills. Modern interpretations of the horns and neck frills are that they were for display, and since chasmosaurines became more common during the Late Campanian and proceeding Maastrichtian, it seems that ceratopsians began to favour larger crests over horns.
Centrosaurus is the classic example of what paleontologists refer to as “centrosaurine” ceratopsians, that is, plant-eating dinosaurs possessing large nasal horns and relatively short frills. This 20-foot-long, three-ton herbivore lived a few million years before Triceratops, and it was closely related to three other ceratopsians, Styracosaurus, Coronosaurus, and Spinops. Centrosaurus is represented by literally thousands of fossils, unearthed from massive “bonebeds” in Canada’s Alberta province.
Einiosaurus has rapidly become one of the more popular ceratopsian dinosaurs thanks mostly to the unusual nasal horn that curves around like a can opener. How the horn grew though is also interesting. In hatch lings the horn would have been a small upwards facing point, and then as juveniles grew the horn would not only increase in length, but would also begin to curve forwards. In the most mature individuals, the horn would curl almost right round upon itself into the distinctive can opener shape.