''Tatankaceratops'' (meaning "

Bison Bison are large bovines in the genus ''Bison'' (Greek: "wild ox" (bison)) within the tribe Bovini. Two extant and numerous extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North ...

horn face") is a controversial

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

ceratopsia Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassi ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

. It is a small chasmosaurine

ceratopsian Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassi ...

which lived during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

period (latest

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interv ...

stage) in what is now

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota peo ...

. It is known from a single partial

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, t ...

which was collected from the

Hell Creek Formation The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation stretches over portions of ...

, dating to 66

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago). ...

. ''Tatankaceratops'' was described by Christopher J. Ott and Peter L. Larson in

2010 File:2010 Events Collage New.png, From top left, clockwise: The 2010 Chile earthquake was one of the strongest recorded in history; The Eruption of Eyjafjallajökull in Iceland disrupts air travel in Europe; A scene from the opening ceremony of ...

and the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

is ''Tatankaceratops sacrisonorum''.Christopher J. Ott and Peter L. Larson, 2010, "A New, Small Ceratopsian Dinosaur from the Latest Cretaceous Hell Creek Formation, Northwest South Dakota, United States: A Preliminary Description", In: Ryan, M.J., Chinnery-Allgeier, B.J., and Eberth, D.A. (eds.) ''New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium'', Bloomington, Indiana University Press, 656 pp. ''Tatankaceratops'' is known from one specimen housed at the Black Hills Institute, BHI 6226. In 2011, Nick Longrich published a paper containing a brief re-evaluation of ''Tatankaceratops''. Longrich suggested that ''Tatankaceratops'' appeared to possess a bizarre mix of characteristics from adult and juvenile ''

Triceratops ''Triceratops'' ( ; ) is a genus of herbivorous chasmosaurine ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the Late Cretaceous period, about 68 million years ago in what is now North America. It is ...

'' 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 ceratopsians. The elongate nose horn meanwhile was characteristic of ''Triceratops'', and specifically, the highly advanced ''Triceratops prorsus''. Longrich noted that this animal could represent a dwarf species of ''Triceratops'' or simply a ''Triceratops'' specimen with a developmental disorder which caused it to stop growing prematurely. Other paleontologists, including

Thomas R. Holtz, Jr. Thomas Richard Holtz Jr. (born September 13, 1965) is an American vertebrate palaeontologist, author, and principal lecturer at the University of Maryland's Department of Geology. He has published extensively on the phylogeny, morphology, ecomorp ...

, have written that they "strongly suspect" ''Tatankaceratops'' is merely a juvenile specimen of ''Triceratops''.Holtz, Thomas R. Jr. (2011) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'
Winter 2010 Appendix.
/ref> Authors of subsequent studies involving triceratopsins have not considered ''Tatankaceratops'' a valid genus.Illies, Matthew M. Canoy, and Denver W. Fowler. "Triceratops with a kink: Co-ossification of five distal caudal vertebrae from the Hell Creek Formation of North Dakota." ''Cretaceous Research'', 108 (2020): 104355.

Systematics

The cladogram below follows Ott and Larson (2010).

References

Chasmosaurines Late Cretaceous dinosaurs of North America Fossil taxa described in 2010 Hell Creek fauna Paleontology in South Dakota Controversial dinosaur taxa Maastrichtian genus first appearances Maastrichtian genus extinctions Ornithischian genera {{ceratopsian-stub

Systematics

See also

References