{{Short description|Extinct order of mammals}} {{Automatic taxobox | fossil_range = {{Fossil range|Late Paleocene|Middle Eocene}} | image = Dinocerata (Pl. LVI) (7159109198).jpg | image_caption = Skeleton of ''Eobasileus'' | image2 = Uintatherium DB.jpg | image2_caption = Life restoration of ''Uintatherium''. | taxon = Dinocerata | authority = Marsh, 1872 | subdivision_ranks = Families and genera | subdivision = See text }}
'''Dinocerata''', from Ancient Greek {{lang|grc|δεινός}} ({{transliteration|grc|deinós}}), "terrible", and {{lang|grc|κέρας}} ({{transliteration|grc|kéras}}), "horn", or '''Uintatheria''',<ref>Blackwelder, R. E. Classification of the Animal Kingdom. Carbondale: Southern Illinois University Press. 1963. p. 71</ref> is an extinct order of large herbivorous hoofed mammals with horns and protuberant canine teeth, known from the Paleocene and Eocene of Asia and North America. With body masses ranging up to {{Convert|4500|kg|lb}} they represent some of the earliest known large mammals.<ref name="Spencer G">Spencer G. Lucas, Robert M. Schoch 19. "Dinocerata" in: Evolution of Tertiary Mammals of North America: Volume 1, Terrestrial Carnivores, Ungulates, and Ungulate like Mammals (1998)</ref>
== Description == [[File:Prodinoceras skull.jpg|left|thumb|Skull of ''Prodinoceras'', one of the earliest dinoceratan genera]] Uintatheriids are suggested to have been browsers. Over the course of their evolution, dinoceratans underwent a great increase in body size, from a weight of {{Convert|175|kg|lb}} in the earliest species to a weight of up to {{Convert|4500|kg|lb}} in the largest species, co-inciding with the development of fully graviportal limbs with a digitigrade posture. Later members of the order are noted for their distinctive pairs of horns that develop from the maxillary and parietal bones of the skull, along with the development of elongated upper canines. The upper incisors were also lost, and the bilophodont nature of the molar teeth was enhanced.<ref name="Spencer G" />
== Evolution == The oldest and most primitive members of the group, such as ''Prodinoceras'', appeared virtually simultaneously during the late Paleocene in North America and Asia, indicating connection between the two landmasses (probably via Beringia<ref>{{Cite journal |last=Mulcahy |first=Kevin D. |last2=Constenius |first2=Kurt N. |last3=Beard |first3=K. Christopher |date=2025-01-10 |title=Nothernmost Record of Dinocerata (Mammalia: Eutheria) in North America from the Middle Eocene Kishenehn Formation of Montana |url=https://bioone.org/journals/annals-of-carnegie-museum/volume-90/issue-3/007.090.0305/Nothernmost-Record-of-Dinocerata-Mammalia--Eutheria-in-North-America/10.2992/007.090.0305.full |journal=Annals of Carnegie Museum |volume=90 |issue=3 |doi=10.2992/007.090.0305 |issn=0097-4463|url-access=subscription }}</ref>), with uintatheres continuing to exchange between the landmasses during the Eocene, as suggested by the presence of ''Uintatherium'' in both North America and China. Uintatheres became extinct towards the end of the Middle Eocene, for unknown reasons.<ref name="Spencer G" />
== Classification == The affinities of the group within Placentalia have historically been contentious. A 2015 phylogenetic study recovered Dinocerata as part of Laurasiatheria, closely related to ungulates and "condylarths", with Dinocerata placed as the sister group to the South American native ungulate group Xenungulata.<ref>{{cite web |last=Burger |first=Benjamin J. |year=2015 |title=The systematic position of the saber-toothed and horned giants of the Eocene: the Uintatheres (Order Dinocerata) |url=http://www.benjamin-burger.org/wp-content/uploads/2019/12/SVP-Poster-Ben-Burger-2015.pdf |location=Utah State University Uintah Basin Campus, Vernal, UT, 84078, United States Of America}}</ref> A close relationship with Xenungulata was first proposed in 1985, with the proposed clade containing both groups named Uintatheriamorpha,<ref name="Spencer G" /> though other authors have suggested that these similarities are likely to be due to convergence.<ref>{{Cite journal |last=Croft |first=Darin A. |last2=Gelfo |first2=Javier N. |last3=López |first3=Guillermo M. |date=2020-05-30 |title=Splendid Innovation: The Extinct South American Native Ungulates |url=https://www.annualreviews.org/doi/10.1146/annurev-earth-072619-060126 |journal=Annual Review of Earth and Planetary Sciences |language=en |volume=48 |issue=1 |pages=259–290 |doi=10.1146/annurev-earth-072619-060126 |issn=0084-6597|url-access=subscription |hdl=11336/136229 |hdl-access=free }}</ref>
==Taxonomy and phylogeny== thumb|Diagram comparing the skulls of ''Eobasileus cornutus'', ''Uintatherium anceps'', and ''Uintatherium insperatus'' Dinocerata is generally divided into two families, "Prodinoceratidae", containing the most primitive genus ''Prodinoceras,<ref name="Spencer G" />'' with some authors also choosing to include the genus ''Probathyopsis''<ref name="Holroyd-2014">{{Cite journal |last=Holroyd |first=Pa |last2=Rankin |first2=Bd |date=2014 |title=Additions to the latest Paleocene Buckman Hollow local fauna, Chappo Member of the Wasatch Formation, Lincoln County, southwestern Wyoming |url=https://palaeo-electronica.org/content/2014/695-buckman-hollow-local-fauna |journal=Palaeontologia Electronica |language=en |doi=10.26879/432 |issn=1094-8074|doi-access=free }}</ref>'','' and Uintatheriidae, containing all other genera. Members of Prodinoceratidae are likely ancestral to Uintatheriidae.<ref name="Spencer G" /> The Asian uintatheriid genus ''Gobiatherium'' is often placed into its own separate subfamily Gobiatheriinae, with all other uintatheriids belonging to the subfamily Uintatheriinae.<ref>{{Cite journal |last=Lucas |first=Spencer G. |date=February 2001 |title=Gobiatherium (Mammalia: Dinocerata) from the Middle Eocene of Asia: Taxonomy and biochronological significance |url=https://link.springer.com/10.1007/BF02988166 |journal=Paläontologische Zeitschrift |language=en |volume=74 |issue=4 |pages=591–600 |doi=10.1007/BF02988166 |issn=0031-0220|url-access=subscription }}</ref> *Order '''Dinocerata''' **Family Prodinoceratidae ***''Prodinoceras'' ***?''Probathyopsis<ref name="Holroyd-2014" />'' **Family Uintatheriidae ***''Gobiatherium'' ***''Probathyopsis'' ***''Bathyopsis'' ***''Uintatherium'' ***''Eobasileus'' ***''Tetheopsis''
{{Portal|Palaeontology}}
==References== {{Reflist}}
{{Taxonbar|from=Q132815}} {{Authority control}}
* Category:Eocene mammals Category:Eocene extinctions Category:Paleocene first appearances Category:Fossil taxa described in 1872 Category:Mammal orders