''Tylocephalonyx'', from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

(''túlos''), meaning "knob", (''képhalos''), meaning "head", and (''ónux''), meaning "claw/hoof", is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

chalicothere Chalicotheriidae (from Ancient Greek ''khálix'', "gravel", and ''theríon'', "beast") is an extinct family of herbivorous, odd-toed ungulate (perissodactyl) mammals that lived in North America, Eurasia, and Africa from the Middle Eocene to the ...

from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

Description

''Tylocephalonyx'' specimens are notable for a dome-shaped skull, a feature found in some other schizotheriine chalicotheres but most developed in this genus. Adequate fossil material is lacking to tell whether both sexes had domed heads, but sexual dimorphism was common in the group. ''Tylocephalonyx'' may have used its "dome" in the same way as the

pachycephalosaurs Pachycephalosauria (; from Ancient Greek, Greek παχυκεφαλόσαυρος for 'thick headed lizards') is a clade of ornithischian dinosaurs. Along with Ceratopsia, it makes up the clade Marginocephalia. With the exception of two species, m ...

, though there is no clear evidence to link either

nor ''Tylocephalonyx'' to using their domes to crash together in high-impact head-to-head contests, as in modern

bighorn sheep The bighorn sheep (''Ovis canadensis'') is a species of Ovis, sheep native to North America. It is named for its large Horn (anatomy), horns. A pair of horns may weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates th ...

. Such contests require special cranial adaptations to protect the brain and cervical spine, not shown in chalicotheres. The dome of ''Tylocephalonyx'' may have been used for visual display or in butting or head-to-body battering contests.

References

Sources

*''National Geographic Prehistoric Mammals'' (

National Geographic ''National Geographic'' (formerly ''The National Geographic Magazine'', sometimes branded as ''Nat Geo'') is an American monthly magazine published by National Geographic Partners. The magazine was founded in 1888 as a scholarly journal, nine ...

) by Alan Turner *''After the Dinosaurs: The Age of Mammals'' (Life of the Past) by Donald R. Prothero *''Classification of Mammals'' by Malcolm C. McKenna and Susan K. Bell *''Late Cretaceous and Cenozoic Mammals of North America: Biostratigraphy and Geochronology'' by Michael O. Woodburne *''Colbert's Evolution of the Vertebrates: A History of the Backboned Animals Through Time'' by Edwin H. Colbert, Michael Morales, and Eli C. Minkoff * Schizotheriinae Miocene Perissodactyla Miocene mammals of North America Fossil taxa described in 1979 {{paleo-oddtoedungulate-stub

Description

See also

References

Sources