Kosmoceratops richardsoni

Kosmoceratops richardsoni was a medium-sized horned dinosaur from the late Campanian Kaiparowits Formation of southern Utah. Its nearly complete skull is one of the most elaborate known among dinosaurs: a blade-like nasal horn, sideways-projecting brow horns, cheek horns and ten curved ornaments around the short broad frill produce the often-quoted total of fifteen horns and spikes. A substantial partial skeleton accompanies the skull, making the animal far better known than many other recently named ceratopsids.

Its fossils occur between approximately 76.4 and 75.5 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The skull approached two metres in length and carried a low blade-like nasal horn. The brow horns projected outward and downward rather than forward, while the cheek horns pointed laterally. Its frill was unusually short and wide for a chasmosaurine, with a row of ten hook-like epiossifications curving across and around its margin. The beaked jaws and closely packed dental batteries cropped and shredded plants. A heavy quadrupedal body, columnar limbs and a short tail are preserved or inferred from the associated skeleton and close relatives.

• Blade-like nasal horn
• Long brow horns directed outward and downward
• Short, broad chasmosaurine frill
• Ten hook-like ornaments around the frill margin
• Large cheek horns projecting from the jugal region
• Deep beak and dental batteries for processing plants

Natural History Museum of Utah and Bureau of Land Management volunteer Scott Richardson found the first material in Grand Staircase–Escalante National Monument in 2006. Museum field crews excavated the fossils and prepared them in Salt Lake City. Scott Sampson and colleagues named Kosmoceratops richardsoni in 2010 from holotype UMNH VP 17000 and referred material. The genus combines Greek kosmos, ornamented, with ceratops, horned face; the species honours Richardson.

Discovery credit: Scott Richardson, Natural History Museum of Utah crews.

Naming authors: Scott D. Sampson, Mark A. Loewen, Andrew A. Farke and 4 coauthors.

The Kaiparowits Formation preserves humid coastal-plain rivers, ponds, wetlands and forests on southern Laramidia, the western landmass of Late Cretaceous North America. Kosmoceratops lived alongside Utahceratops, the hadrosaur Gryposaurus monumentensis, the tyrannosaur Teratophoneus and smaller theropods including Talos. The map marker represents the broad fossil-bearing plateau rather than a protected quarry coordinate.

Kosmoceratops was a low-browsing herbivore that cropped vegetation with a beak and processed it with dental batteries. Its elaborate frill and horns probably played an important visual role in recognizing species or signalling to other individuals; defence and physical competition are also possible. Their exact colours, sex differences and use in combat are unknown. No direct evidence demonstrates herd size or parental care.

• Its head is conventionally counted as carrying fifteen horns and spikes.
• The skull alone is just under two metres long.
• The frill was shorter and broader than the long frills of many other chasmosaurines.
• Both named specimens are housed at the Natural History Museum of Utah.

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1. 01
   The Paleobiology Database

   Open source
2. 02
   New Horned Dinosaurs from Utah Provide Evidence for Intracontinental Dinosaur Endemism

   Scott D. Sampson, Mark A. Loewen, Andrew A. Farke and 4 coauthors · PLOS ONE 5(9), e12292 · 2010

   Open source
3. 03
   Kosmoceratops richardsoni

   Natural History Museum of Utah

   Open source