For over a year and a half, a mystery dinosaur has been hanging on the trophy wall of the Natural History Museum of Utah. The nameless Cretaceous herbivore isn’t quite like the neighboring horned dinosaurs arrayed in the display’s evolutionary rank and file. The deep-snouted dinosaur has a U-shaped set of long, curved brow horns and small, scalloped ornaments decorating the perforated frill – flashy headgear distinct from the short brow-horned, spiky-frilled look of the dinosaur’s close cousins Centrosaurus and Styracosaurus. Today, this bizarre 75 million year old dinosaur finally gets a name.
Dubbed Nasutoceratops titusi, the “large-nosed horned face” is described by paleontologist Scott Sampson and colleagues in the Proceedings of the Royal Society B. (The dinosaur’s species name, titusi, honors Bureau of Land Management paleontologist Alan Titus.) The paper is the culmination of a 2010 master’s thesis paleontologist Eric Lund undertook at the University of Utah in which the known remains of the dinosaur were prepared, studied, described, and even named, but could not be officially counted in the Mesozoic menagerie until the new publication. Now that the formalities are out of the way, Nasutoceratops can take its place within the wildly branching pattern of horned dinosaur evolution.
About 75 million years ago, when Nasutoceratops roamed, southern Utah was practically shorefront property. Instead of being a landlocked four corners state, Cretaceous Utah abutted the edge of the long-vanished Western Interior Seaway that split North America into two continents – Appalachia to the east and Laramidia to the west. The part of Laramidia that Nasutoceratops inhabited is preserved in Grand Staircase-Escalante National Monument’s Kaiparowits Formation, recording an era when strange species of dinosaurs trod through lush coastal swamps.
Species by species, paleontologists have been naming the unusual dinosaurs of the Kaiparowits Formation. In 2010, for example, some of the same researchers behind the Nasutoceratops paper described Utahceratops and Kosmoceratops from the same slice of geologic time. Nasutoceratops is the third horned dinosaur to have browsed the same humid habitats, but was a different sort of herbivore than those previously known.
In technical parlance, large horned dinosaurs are called ceratopsids. There are two ceratopsid subgroups which split from each other between 90 and 80 million years ago. There were the chasmosaurines – such as Utahceratops, Kosmoceratops, and the famous Triceratops – and the centrosaurines, of which Nasutoceratops is the latest member to be described.
Known from a mostly-complete skull, forelimb and neck elements, as well as several other disarticulated skull pieces, Nasutoceratops seems to retain an archaic centrosaurine skull type. Whereas early centrosaurines had long brow horns and short nasal horns, later forms – such as Centrosaurus and Styracosaurus – had short brow horns, long nasal horns or bosses, and extravagant frill decorations that were much more prominent than the little nubs on Nasutoceratops. While Nasutoceratops lived at about the same time as Centrosaurus and Styracosaurus, the newly-named dinosaur represents an early, persistent offshoot of the same subgroup that kept the long-brow-horns, short-nasal-horns style going.
That such a strange centrosaurine existed in the southern ranges of Laramidia adds to the growing body of evidence that some sort of barrier caused dinosaurian evolution to diverge on the lost continent shortly before 75 million years ago. The genera and species of dinosaurs found in Grand Staircase-Escalante National Monument and other southern sites are distinct from those previously discovered in Canada and other northern locales. The great, unresolved question is what this barrier was. The dinosaurs – hadrosaurs, tyrannosaurs, ankylosaurs, ceratopsids, and more – give away the pattern of a great evolutionary split, but the reasons and mechanics of that event have not yet come into focus.
Not that there aren’t further mysteries within Nasutoceratops itself. Naming a dinosaur is just an initial step in understanding the animal. Nasutoceratops is found in the same formation as two other large ceratopsids, for example, not to mention several other heavy herbivores. Were all these dinosaurs neighbors that preferred different sorts of vegetation to circumvent competition – as megaherbivores of the same era in prehistoric Canada did – or did these dinosaurs occupy similar habitats at different times? The ecology of Nasutoceratops is an open question.
And then there’s the dinosaur’s nose. Within that Jimmy Durante profile, the nose of Nasutoceratops had large air spaces – or “pneumatic excavations” – that have never been seen in any other horned dinosaur. Did these nasal spaces have a peculiar function? No one yet knows. That, and the rest of the dinosaur’s biology, is almost entirely unknown, particularly since most of the skeleton has yet to be found. Enough of the magnificent ceratopsid has been uncovered to know that Nasutoceratops was something different, but the life of the horned herbivore awaits discovery.
[Full disclosure: I volunteer in the paleontology department of the Natural History Museum of Utah, where Nasutoceratops is curated and some of the new study’s research was conducted.]
Sampson, S., Lund, E., Loewen, M., Farke, A., Clayton, K. 2013. A remarkable short-snouted horned dinosaur from the Late Cretaceous (late Campanian) of southern Laramidia. Proceedings of the Royal Society B. 280: 20131186