''Eobasileus cornutus'' ("horned dawn-king") was a prehistoric

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of dinocerate mammal.

Description

With a skull about in length, and standing some tall at the shoulder, with a weight estimated to be around , ''Eobasileus'' was the largest

uintathere Dinocerata, from Ancient Greek (), "terrible", and (), "horn", or Uintatheria, 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 ...

. It looked much like the related ''

Uintatherium ''Uintatherium'' ("Beast of the Uinta Mountains") is an extinct genus of herbivorous dinoceratan mammal that lived during the Eocene epoch. Two species are currently recognized: ''U. anceps'' from the United States during the Early to Middle Eoc ...

''. Like ''Uintatherium'', it had three pairs of blunt

horns Horns or The Horns may refer to: * Plural of Horn (anatomy) * Plural of Horn (instrument), a group of musical instruments all with a horn-shaped bells * The Horns (Colorado), a summit on Cheyenne Mountain * Horns (novel), ''Horns'' (novel), a dar ...

on its skull, possibly covered with skin like the

ossicone Ossicones are columnar or conical skin-covered bone structures on the heads of giraffes, male okapi, and some of their extinct relatives. Ossicones are distinguished from the superficially similar structures of Horn (anatomy), horns and antlers ...

s of a

giraffe The giraffe is a large Fauna of Africa, African even-toed ungulate, hoofed mammal belonging to the genus ''Giraffa.'' It is the Largest mammals#Even-toed Ungulates (Artiodactyla), tallest living terrestrial animal and the largest ruminant on ...

. The frontal pair may have been composed of

keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. It is the key structural material making up Scale (anatomy), scales, hair, Nail (anatomy), nails, feathers, horn (anatomy), horns, claws, Hoof, hoove ...

, like the horn(s) of a

rhinoceros A rhinoceros ( ; ; ; : rhinoceros or rhinoceroses), commonly abbreviated to rhino, is a member of any of the five extant taxon, extant species (or numerous extinct species) of odd-toed ungulates (perissodactyls) in the family (biology), famil ...

. ''Eobasileus'' also had a pair of

tusks Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine teeth, as with narwhals, chevrotains, musk deer, water deer, muntjac, pigs, peccaries, hippopota ...

shielded by bony protrusions of the

lower jaw In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

. A dispute over ''Eobasileus'' specifically and the uintatheres more generally helped to spark the

Bone Wars The Bone Wars, also known as the Great Dinosaur Rush, was a period of intense and ruthlessly competitive fossil hunting and discovery during the Gilded Age of American history, marked by a heated rivalry between Edward Drinker Cope (of the Aca ...

between

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontology, paleontologist, comparative anatomy, comparative anatomist, herpetology, herpetologist, and ichthyology, ichthyologist. Born to a wealthy Quaker fam ...

and

Othniel Charles Marsh Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of paleontology. A prolific fossil collector, Marsh was one of the preeminent paleontologists of the nineteenth century. Among his legacies are the discovery or ...

. Cope, Marsh, and

Joseph Leidy Joseph Mellick Leidy (September 9, 1823 – April 30, 1891) was an American paleontologist, parasitologist and anatomist. Leidy was professor of anatomy at the University of Pennsylvania, later becoming a professor of natural history at Swarth ...

independently discovered specimens from related species—though Cope and Marsh believed they had each discovered the same species—in the

Fort Bridger Fort Bridger was originally a 19th-century fur trading outpost established in 1842, on Blacks Fork of the Green River, in what is now Uinta County, Wyoming, United States and was then part of Mexico. It became a vital resupply point for wagon ...

area, leading to disputes over naming rights for the animals and a series of increasingly hostile letters to various scientific journals. In 1873, for example, Marsh wrote "Cope has endeavored to secure priority by sharp practice, and failed…Prof. Cope's errors will continue to invite correction, but these, like his blunders, are hydra-headed, and life is really too short to spend valuable time in such an ungracious task, especially as in the present case Prof. Cope has not even returned thanks for the correction of nearly half a hundred errors…" The ''

American Naturalist ''The American Naturalist'' is the monthly peer-reviewed scientific journal of the American Society of Naturalists, whose purpose is "to advance and to diffuse knowledge of organic evolution and other broad biological principles so as to enhance th ...

'' declined to print this letter as a scientific article, but did publish it as an appendix; Marsh paid for its inclusion in the journal.

References

Dinoceratans Eocene mammals of North America Fossil taxa described in 1872 Eocene United States Prehistoric placental genera Taxa named by Edward Drinker Cope {{paleo-mammal-stub