Misplaced Pages

This is the current revision of this page, as edited by GreenC bot (talk | contribs) at 20:06, 18 November 2024 (Move 1 url. Wayback Medic 2.5 per WP:URLREQ#paleodb.org). The present address (URL) is a permanent link to this version.

Miohippus Temporal range: late Eocene to late Oligocene
Skeleton
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Perissodactyla
Family:	Equidae
Subfamily:	†Anchitheriinae
Genus:	†Miohippus Marsh, 1874
Species
See text

Miohippus (meaning "small horse") is an extinct genus of horse existing longer than most Equidae. It lived in what is now North America from 32 to 25 million years ago, during the late Eocene to late Oligocene. According to the Florida Museum of Natural History, Othniel Charles Marsh first believed Miohippus lived during the Miocene and thus named the genus using this incorrect conclusion. More recent research provides evidence that Miohippus actually lived during the Paleogene period.

Miohippus species are commonly referred to as the three-toed horses. Their range was from Alberta, Canada to Florida to California.

Taxonomy

The type species of Miohippus, M. annectens, was named by Marsh in 1874. It is classified as a member of the subfamily Anchitheriinae following MacFadden (1998).

Species list

• M. anceps Marsh, 1874
• M. annectens Marsh, 1874 Type species
• M. assiniboiensis Lambe, 1905
• M. condoni Leidy, 1870
• M. equiceps Cope, 1879
• M. equinanus Osborn, 1918
• M. gemmarosae Osborn, 1918
• M. gidleyi Osborn, 1904
• M. intermedius Osborn & Wortman, 1895
• M. longicristis Cope, 1878
• M. obliquidens Osborn, 1904
• M. primus Osborn, 1918
• M. quartus Osborn, 1918

Description

The species M. obliquidens dating from 34.9 to 30.0 Ma found in Montana, North Dakota, South Dakota, and Nebraska when calculated for estimated body mass were within the margin of 25 to 30 kg. Miohippus became much larger than Mesohippus. They weighed around 40 to 55 kilograms. They were somewhat larger than most earlier Eocene horse ancestors, but still much smaller than modern horses, which typically weigh about 500 kilograms.

Miohippus was larger than Mesohippus and had a slightly longer skull. Its facial fossa was deeper and more expanded, and the ankle joint was subtly different. Miohippus also had a variable extra crest on its upper molars, which gave it a larger surface area for chewing tougher forage. This would become a typical characteristic of the teeth of later equine species.

Miohippus had two forms, one of which adjusted to the life in forests, while the other remained suited to life on prairies. The forest form led to the birth of Kalobatippus (or Miohippus intermedius), whose second and fourth finger again elongated for travel on the softer primeval forest grounds. The Kalobatippus managed to relocate to Asia via the Bering Strait land bridge, and from there moved into Europe, where its fossils were formerly described under the name Anchitherium. Kalobatippus is then believed to have evolved into a form known as Hypohippus, which became extinct near the beginning of the Pliocene.

As many as eight species of Miohippus were described from the John Day Formation of Oregon, but recent work on the dental variation has determined that only one species of Miohippus was present within a given member.

See also

• Evolution of the horse

References

1. McKenna, M. C & S. K. Bell (1997). Classification of Mammals Above the Species Level. Columbia University Press. ISBN 0-231-11012-X.
2. "Miohippus". Florida Museum. 2018-02-16. Retrieved 2022-10-04.
3. B. J. MacFadden. 1998. Equidae. In C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), Evolution of Tertiary Mammals of North America 1:537-559.
4. Paleobiology Database Miohippus entry Accessed 8 December 2011
5. Barbour, E. H. (2018-04-17). "A New Fossil Horse, "Hypohippus Matthewi"". Conservation and Survey Division. Retrieved 2022-05-23.
6. Famoso, Nicholas (July 21, 2017). "Statistical analysis of dental variation in the Oligocene equid Miohippus (Mammalia, Perissodactyla) of Oregon". Journal of Paleontology. 91 (5): 1060–1068. Bibcode:2017JPal...91.1060F. doi:10.1017/jpa.2017.42.

External links

• "Evolution of the Horse". Geocities. Archived from the original on October 27, 2009.
• "Horse Evolution (by Kathleen Hunt)". Talkorigins. Archived from the original on November 13, 2023.
• "Evolution of Horses". Ecology. Archived from the original on June 9, 2017.

v t e Perissodactyla
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Perissodactyla
Perissodactyla Incertae sedis †Ghazijhippus †Mesolambdolophus †Olbitherium †Anthracobunia Radinskya †Anthracobunidae Anthracobune Hsanotherium Jozaria Obergfellia †Cambaytheriidae Cambaytherium Kalitherium Nakusia Perissobune †Brontotheriidae See Brontotheriidae Equoidea †Cymbalophus †Hallensia †Pliolophus †Systemodon Equidae See Equidae †Palaeotheriidae †Pachynolophinae Anchilophus Bepitherium Eurohippus Hyracotherium Lijiangia Lophiohippus Lophiotherium Metanchilophus Orolophus Pachynolophus Paranchilophus Propalaeotherium Qianohippus †Palaeotheriinae Cantabrotherium Iberolophus Idiodontherium Leptolophus Mekodontherium Metaplagiolophus Palaeotherium Paraplagiolophus Plagiolophus Pseudopalaeotherium †Hyopsodontidae? Aletodon Chacomylus Dorraletes Haplaletes Haplomylus Hyopsodus Litomylus Louisina Monshyus Paratricuspiodon Paschatherium Phenacodaptes Tricuspiodon †Phenacodontidae? Tetraclaenodon †Meniscotheriinae Ectocion Meniscotherium †Phenacodontinae Almogaver Copecion Eodesmatodon Lophocion Phenacodus Tapiromorpha See below↓
Tapiromorpha Incertae sedis †Cambaylophus †Skopaiolophus †Isectolophidae Chowliia Gandheralophus Karagalax Meridiolophus Orientolophus Sastrilophus †Homogalaxinae Homogalax †Isectolophinae Isectolophus Schizolophodon †Ancylopoda See Ancylopoda Ceratomorpha Tapiroidea †Deperetellidae Bahinolophus Deperetella Irenolophus Teleolophus †Helaletidae Colodon Dilophodon Helaletes Heptodon Heteraletes Paracolodon Plesiocolopirus Thuliadanta? Vastanolophus Tapiridae †Eotapirus †Miotapirus †Nexuotapirus †Paratapirus †Plesiotapirus †Protapirus †Tapiravus Tapirus Rhinocerotoidea See below↓
Rhinocerotoidea Rhinocerotoidea sensu lato †Breviodon †Fouchia †Minchenoletes †Siamolophus †Triplopus †Yimengia †Indolophidae Indolophus Rhinocerotoidea sensu stricto †Selenaletes †Hyrachyidae Hyrachyus †Eggysodontidae Allacerops Eggysodon Guangnanodon Proeggysodon †Hyracodontidae Ardynia Ephyrachyus Epitriplophus Hyracodon Prohyracodon Rhodopagus Triplopides †Amynodontidae Amynodontopsis Armania Cadurcotherium Caenolophus Huananodon Hypsamynodon Procadurcodon Rostriamynodon Teilhardia †Amynodontinae Amynodon †Cadurcodontini Cadurcodon Lushiamynodon Sharamynodon Sianodon †Metamynodontini Gigantamynodon Megalamynodon Metamynodon Paramynodon Zaisanamynodon †Paraceratheriidae †Forstercooperiinae Forstercooperia Gobicerops Pappaceras †Paraceratheriinae Aralotherium Dzungarotherium Juxia Paraceratherium Urtinotherium Rhinocerotidae See below↓
Rhinocerotidae Rhinocerotidae †Amphicaenopus †Epiaceratherium †Guixia †Teletaceras †Uintaceras †Woodoceras †Aceratheriinae Aceratherium Acerorhinus Alicornops Aphelops Chilotheridium Chilotherium Floridaceras Galushaceras Hoploaceratherium Mesaceratherium Peraceras Persiatherium Plesiaceratherium Ronzotherium Shansirhinus Sinorhinus Subchilotherium †Elasmotheriinae Gulfoceras Victoriaceros †Diceratheriini Diceratherium Penetrigonias Skinneroceras Subhyracodon Trigonias †Elasmotheriini Bugtirhinus Caementodon Elasmotherium Hispanotherium Iranotherium Kenyatherium Meninatherium Menoceras Ninxiatherium Ningxiatherium Ougandatherium Parelasmotherium Procoelodonta Sinotherium Tongxinotherium Rhinocerotinae †Dromoceratherium †Lartetotherium †Molassitherium †Protaceratherium †Teleoceratini Aprotodon Brachydiceratherium Brachypotherium Diaceratherium Prosantorhinus Shennongtherium Teleoceras Rhinocerotina Dicerorhinini †Coelodonta Dicerorhinus †Dihoplus †Pliorhinus †Stephanorhinus Dicerotini Ceratotherium Diceros †Miodiceros †Paradiceros Rhinocerotini †Gaindatherium †Nesorhinus Rhinoceros †Rusingaceros

• Anchitheriinae
• Fossils of Canada
• Paleontology in Alberta
• Eocene horses
• Oligocene horses
• Eocene mammals of North America
• Oligocene mammals of North America
• Prehistoric placental genera
• Eocene genus first appearances
• Oligocene extinctions
• Fossil taxa described in 1874
• Taxa named by Othniel Charles Marsh