Prehistoric Life/Dinosaurs/Ceratopsids: Difference between revisions

* Ceratopsids are classically known as “horned dinosaurs”: but this one seems not to have liked our definition. ''Pachyrhinosaurus'' (“thick-nosed lizard”), at a first glance, resembles more an oversized ''Protoceratops'' than a ''Triceratops'': it has no true horns on its skull, it had a thickened boss upon its nose, sometimes described as similar to a lunar crater. To compensate, its short frill has an elaborate shape, with two horn-like spikes protruding from its rear-corners, other minor undulations elsewhere, and a small prominence pointing upwards from the center of the shield. It’s worth noting, however, that juvenile pachyrhinosaurs did have a typical ceratopsid nose horn that was absorbed into the skull as they grew. This detail, along with its great size, massive limbs and other elements, firmly demonstrates that it is a true ceratopsid, more precisely a Centrosaurine - that is, a relative of ''Centrosaurus'' and ''Styracosaurus''. Before the nineties ''Pachyrhinosaurus'' was one of the rarest ceratopsids: then, in the 1990s, a whole herd was discovered in Alaska. Since other ''Pachyrhinosaurus'' remains have been found much souther, this might be another proof of migrating behavior among horned dinosaurs. ''Pachyrhinosaurus'' should never get confounded with ''[[Stock Dinosaurs|Pachycephalosaurus]]'': both had something “thick” in their skull, but in the latter’s case was the ''head''. Another thick-nosed, horn-lacking ceratopsid was discovered in the 1990s, ''Achelousaurus''.

* Maths are not always a exclusively-nerd thing. It can also be amusing, expecially when you can apply it to dinosaurs. ''Chasmosaurus'' can just be recognized by the geometry of its frill: strikingly angular in shape, if seen frontally almost seemed a reversed Isosceles Triangle with the base on the top and the apex attached to the skull. Its edge was also complex: smooth and V-shaped at the “hypothenusa”, spiky on the two upper corners, and half-smooth / half-undulating on the two “cathetes”. Moreover, this frill was also extremely elongated, almost like the ''Torosaurus'' one, and was arguably used for the same purpose. The remaining head was far less spectacular: the horns were three like''Triceratops'', but were rather short in comparison – some individuals had mere hints of the frontal ones; we’re not sure if they’re from females or distinct species. Known since the 1910s, ''Chasmosaurus'' is one of the most common ceratopsids in fossil record, and is often considered the prototype of the (usually) long-shielded subgroup, the Chasmosaurines (or Ceratopsines). However, the genus ''Chasmosaurus'' has been recently split in several new genera (year 2010). In Fictionland, the chasmosaur was portrayed in one old movie, and some modern-cartoon ''Triceratops'' have a suspiciously ''Chasmosaurus''-like triangular frill.

* Despite many of the aforementioned ceratopsians had the usual “saurus” ending, most described genuses have the same suffix of the Great-Stock member. ''-ceratops''es do abund here: after ''Triceratops'' (“three horned face”) and ''Protoceratops'' (“first horned face”), the most well-known is ''Pentaceratops'' (“''five-horned'' face”). But did it really had five horns? Well… no. They were only three. The other two “horns” actually were simple protrusions arising from each cheekbone - a common ceratopsian trait, but particularly evident in ''Pentaceratops''. One of the classic long-frilled ceratopsids, ''Pentaceratops'' was pratically the intermediate form between ''Torosaurus'' and ''Chasmosaurus'': smaller than ''Torosaurus'' but bigger than ''Chasmosaurus'', lived before the former but after the latter. Its horns were shorter than ''Torosaurus'' but more developed than many ''Chasmosaurus''es. Its frill was neither elliptical / smooth like the Toro’s one, nor triangular / complex like the Chasmo’s: it was rectangular and lightly serratead around its whole perimeter. Known since the first half of the XX century from remains discovered in Texas, ''Pentaceratops'' gained more attention in the 1990s after the discover of a gigantic skull which was attributed to its genus. Before that, ''Torosaurus'', with its 2.5 m long skull, used to bear the record for “the biggest-headed land animal ever”; this putative pentaceratops’ skull was ''3 m long''. [[Science Marches On|Science Has Marched On]] however, and this specimen has been deemed a separate animal in January 2011, ''Titanoceratops''.

* Well, it’s true: ceratopsids have really bizarre hairdos. The most astonishing is, needless to say, that of [[Stock Dinosaurs|Styracosaurus]], with its multiple “horns” protruding from the frill. But some relatives made even their frontal horn a very odd-looking thing: for example ''Einiosaurus''. Only discovered in the 1990s, it was initially believed a new styracosaurian species, but with only two terminal spikes on its shield. The strange thing here is the nasal horn: strongly curved, thickened and pointing forwards, as the animal could signal its target like a pointer dog… more realistically, its shape could have been for ornamental purpose. As recently as years 2010/2011, many new ceratopsid species have been discovered, with various frill-shapes. The most spectacular is ''Kosmoceratops'': similar to ''Chasmosaurus'', it shows an entire set of curved hooks protruding from the frill-top like a [[Bizarre Hair|fanciful fringe]].

[[Category:Prehistoric Life Ceratopsids]]