| Tatankaceratops | |
|---|---|
 | |
| Artist's restoration ofTatankaceratops | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | †Ornithischia |
| Clade: | †Ceratopsia |
| Family: | †Ceratopsidae |
| Subfamily: | †Chasmosaurinae |
| Tribe: | †Triceratopsini |
| Genus: | †Tatankaceratops Ott & Larson,2010 |
| Species: | †T. sacrisonorum |
| Binomial name | |
| †Tatankaceratops sacrisonorum Ott & Larson, 2010 | |
Tatankaceratops (meaning "bison horned face") is a controversialgenus ofherbivorouschasmosaurineceratopsiddinosaur that lived during theLate Cretaceousperiod (latestMaastrichtian stage, about 66million years ago) in what is now the upperHell Creek Formation, inSouth Dakota. It is known from a single partialskull housed at theBlack Hills Institute, BHI 6226, described by Christopher J. Ott andPeter L. Larson in2010 as thetype speciesTatankaceratops sacrisonorum.[1]
In 2011,Nick Longrich published a paper containing a brief re-evaluation ofTatankaceratops. He suggested that the genus appeared to possess a bizarre mix of characteristics from adult and juvenileTriceratops specimens; the animal's small size and short, slender brow horns are consistent with the animal being a juvenile, but the gnarled bone and fusion of skull elements to one another are typical of old adult ceratopsids. The elongate nose horn meanwhile was characteristic ofTriceratops, and specifically, the highly advancedT. prorsus. Longrich also noted that this animal could represent a dwarf species ofTriceratops or simply a specimen of the aforementioned genus with a developmental disorder which caused it to stop growing prematurely.[2] Other paleontologists, includingThomas R. Holtz, Jr., have written that they "strongly suspect"Tatankaceratops is merely a juvenile specimen ofTriceratops.[3] Authors of subsequent studies involving triceratopsins have not considered it a valid genus.[4]
The cladogram below follows Ott and Larson (2010).[1]
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