Sunday, November 25, 2018

Nasutoceratops: Prehistoric Beast of the Week

Today we take a look at a really cool looking plant-eating ceratopsia called Nasutoceratops titusi.

Nasutoceratops titusi life reconstruction by Christopher DiPiazza.

Nasutoceratops measured about fifteen feet long from beak to tail when it was alive.  It lived in what is now Utah, USA, during the late Cretaceous period, between 75 and 76 million years ago.  Nasutoceratops translates to "Big Nosed Horned Face" because of its extremely thick snout.

Nasutoceratops was an early member of the centrosaurine branch of the ceratopsian family of dinosaurs.  Centrosaurines are characterized by having short, very tall snouts.  Nasutoceratops has perhaps the most extreme case of this feature, which is how it got its genus name.  This huge nasal cavity may have served a number of purposes, from sound amplification, to a structure for maintaining moisture.  The big nose may have also been for visual display within the species.

There have been a lot of interesting ceratopsians over the last several years, many of which have very unique horn and frill structures.  That being said, I personally think Nasutoceratops is the coolest out of this bunch.  It doesn't really have much on its nose, but its brow horns were a different story.  They grew outwards to the sides of the animal's face then curved inwards towards the middle, very similar to the horns of some modern bulls.  These horns are also interesting because Nasutoceratops' later relatives from the centrosaurine group, like Centrosaurus, StyracosaurusPachyrhinosaurus, or Sinoceratops, possessed very short brow horns, or no brow horns at all, but typically had large horns or bony structures on their snouts and even their frills.  Nasutoceratops implies that long brow horns may have been an ancestral trait to the large ceratopsians, but the centrosaurine branch turned them in for more elaborate nose structures as time went on.

Nasutoceratops' frill was relatively small and circular shaped, with prominent scallop-shaped horny structures growing out of the edges.

Nasutuceratops skull


Not only bones are known from Nasutoceratops.  This dinosaur is one of the few that we actually have skin casts from!  A small patch of skin, thought to be from the arm, shows mosaic-like scales, similar to those we can see on modern crocodilians.  We have a small record of skin impressions from a few other kinds of ceratopsians, including Triceratops, Chasmosaurus, and Centrosaurus, but those are all from different parts of the body, mostly the back and hip area.

Nasutoceratops skin cast.   Note the different sized scales.  Photo used with permission courtesy of Brian Switek.

Nasutoceratops is an interesting and important dinosaur because Ceratopsids in the centrosaurine group (thick-snouted ones also including Diabloceratops, Styracosaurus and Pachyrhinosaurus) are rare in the Southern United States.  Many of them are actually found farther north in Canada.  Nasutoceratops provides us with more clues (and questions) about ceratopsid evolution and geographical distribution.


References

Sampson, S. D.; Lund, E. K.; Loewen, M. A.; Farke, A. A.; Clayton, K. E. (2013). "A remarkable short-snouted horned dinosaur from the Late Cretaceous (late Campanian) of southern Laramidia". Proceedings of the Royal Society B: Biological Sciences 280 (1766): 20131186. doi:10.1098/rspb.2013.1186

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