Moropus
Encyclopedia
Moropus is an extinct genus of mammal
, belonging to a group called chalicothere
s, which were perissodactyl ("odd-toed") mammals, endemic to North America
during the Miocene
from ~23.0—13.6 Mya, existing for approximately .
Moropus is related to the modern horse
, rhino
, and tapir
.
by Geraads et al. (2007).
s, they differed from their modern relatives in having large claws, rather than hooves, on the front feet; these claws may have been used for defense or digging for food. Moropus stood about 8 feet (2.4 m) tall at the shoulder. The three highly compressed claw-like hooves on each foot were split down the middle. These claws actually gave Moropus its name: " slow "or "sloth foot". This name implies that because of the claws, Moropus was a clumsy mover. But the articulation of the phalangeal (finger) bones, in addition to probable large foot and toe pads, shows that Moropus probably could raise the claws slightly to enable it to move about quite smoothly. Because the hooves curve inward, it probably had a pigeon-toed gait.
Body mass
Two specimens were examined by M. Mendoza, C. M. Janis, and P. Palmqvist for body mass.
Fossil distribution
Fossil distribution
Fossil distribution
Body mass
Two specimens were examined by M. Mendoza, C. M. Janis, and P. Palmqvist for body mass.
Fossil distribution
by Coombs (1978) and Coombs (1998).
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
, belonging to a group called chalicothere
Chalicothere
Chalicotheres were a group of herbivorous, odd-toed ungulate mammals spread throughout North America, Europe, Asia, and Africa during the Early Eocene to Early Pleistocene subepochs living from 55.8 mya—781,000 years ago, existing for approximately .They evolved around 40 million years ago from...
s, which were perissodactyl ("odd-toed") mammals, endemic to North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
during the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
from ~23.0—13.6 Mya, existing for approximately .
Moropus is related to the modern horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
, rhino
Rhinoceros
Rhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....
, and tapir
Tapir
A Tapir is a large browsing mammal, similar in shape to a pig, with a short, prehensile snout. Tapirs inhabit jungle and forest regions of South America, Central America, and Southeast Asia. There are four species of Tapirs: the Brazilian Tapir, the Malayan Tapir, Baird's Tapir and the Mountain...
.
Taxonomy
Moropus was named by Marsh (1877). Its type is Moropus distans. It was synonymized subjectively with Macrotherium by Osborn (1893). It was assigned to Moropodidae by Marsh (1877); to Chalicotheriidae by Marsh (1877), Peterson (1907), Skinner (1968), Coombs (1978), Carroll (1988), Coombs (1998) and Holbrook (1999); and to SchizotheriinaeSchizotheriinae
Schizotheriines make up an extinct clade of the family Chalicotheriidae, a group of herbivorous, odd-toed ungulate mammals. Unlike the gorilla-like proportions of other chalicotheres, schizotheriines had smaller body proportions, closer to those of Moropus. Analysis of dental microwear implies...
by Geraads et al. (2007).
Morphology
Like other chalicothereChalicothere
Chalicotheres were a group of herbivorous, odd-toed ungulate mammals spread throughout North America, Europe, Asia, and Africa during the Early Eocene to Early Pleistocene subepochs living from 55.8 mya—781,000 years ago, existing for approximately .They evolved around 40 million years ago from...
s, they differed from their modern relatives in having large claws, rather than hooves, on the front feet; these claws may have been used for defense or digging for food. Moropus stood about 8 feet (2.4 m) tall at the shoulder. The three highly compressed claw-like hooves on each foot were split down the middle. These claws actually gave Moropus its name: " slow "or "sloth foot". This name implies that because of the claws, Moropus was a clumsy mover. But the articulation of the phalangeal (finger) bones, in addition to probable large foot and toe pads, shows that Moropus probably could raise the claws slightly to enable it to move about quite smoothly. Because the hooves curve inward, it probably had a pigeon-toed gait.
Body mass
Two specimens were examined by M. Mendoza, C. M. Janis, and P. Palmqvist for body mass.- Specimen 1: 95.5 kg (210.5 lb)
- Specimen 2: 134.2 kg (295.9 lb)
Fossil distribution
- Phillips Ranch, Kern County, CaliforniaKern County, CaliforniaSpreading across the southern end of the California Central Valley, Kern County is the fifth-largest county by population in California. Its economy is heavily linked to agriculture and to petroleum extraction, and there is a strong aviation and space presence. Politically, it has generally...
estimated age: ~18.7 Mya. - Stewart Spring(UCMP 2027), Mineral CountyMineral County, NevadaMineral County is a county located in the U.S. state of Nevada. As of the 2000 census, the population was 5,071. In 2009, it was estimated to have dropped to 4,662. Its county seat is Hawthorne.-History:...
and Esmeralda County, NevadaEsmeralda County, NevadaEsmeralda County is a county in the west of U.S. state of Nevada. Its county seat is Goldfield. Its 2000 census population was officially 971, making its population density 0.1045 inhabitants/km² , the second-lowest of any county-equivalent outside of Alaska. As of 2010, the population had...
estimated age: ~18.7 Mya. - Stage Hill I, aka Millennium's End Quarry, Scotts Bluff County, NebraskaScotts Bluff County, Nebraska-National protected area:* North Platte National Wildlife Refuge* Scotts Bluff National Monument-Demographics:As of the census of 2000, there were 36,951 people, 14,887 households, and 10,167 families residing in the county. The population density was 50 people per square mile . There were 16,119...
estimated age: ~21.6—21.5 Mya. - Sucker Creek site, Sucker Creak Formation, Malheur County, OregonMalheur County, OregonMalheur County is a county located in the southeast corner of the U.S. state of Oregon. It is included in the eight-county definition of Eastern Oregon. Most of the county observes the Mountain Time Zone, although the southern quarter of the county observes the Pacific Time Zone along with the...
~16.4 Mya.
M. elatus
M. elatus was named by Marsh (1877).Body mass
Two specimens were examined by M. Mendoza, C. M. Janis, and P. Palmqvist for body mass.
- Specimen 1: 118.4 kg (261 lb)
- Specimen 2: 296.8 kg (654.3 lb)
Fossil distribution
- Granby site, Grand County, ColoradoGrand County, ColoradoGrand County is the 21st largest of the 64 counties of the State of Colorado of the United States. The county population was 12,442 at U.S. Census 2000...
~23 Mya. - Agate Springs Quarries, Sioux County, NebraskaSioux County, Nebraska-National protected areas:* Agate Fossil Beds National Monument* Nebraska National Forest * Oglala National Grassland -Demographics:...
, estimated age: ~20.9—20.8 Mya. - American Museum-Cook Quarry, Sioux County, Nebraska, estimated age: ~23.03—5.33 Mya.
- Cart Trail Quarry, Box Butte County, NebraskaBox Butte County, Nebraska-Demographics:As of the census of 2000, there were 12,158 people, 4,780 households, and 3,298 families residing in the county. The population density was 11 people per square mile . There were 5,488 housing units at an average density of 5 per square mile...
, estimated age: ~23.0—20.3 Mya. - Morava Ranch Quarry, Box Butte County, Nebraska, estimated age: ~21.6 Mya.
M. hollandi
M. hollandi was named by Peterson (1907).Fossil distribution
- Chugwater (aka Chugwater Water Hole), Platte County, Wyoming, estimated age: ~20.7 Mya.
- Jay Em, Goshen County, Wyoming, estimated age: ~20.7 Mya.
- Niobrara Canyon, Sioux County, NebraskaSioux County, Nebraska-National protected areas:* Agate Fossil Beds National Monument* Nebraska National Forest * Oglala National Grassland -Demographics:...
, estimated age: ~20.7 Mya.
M. merriami
M. merrami was named by Holland and Peterson (1914). It was recombined as Macrotherium merriami by Matthew (1929) and Stirton (1939); it was recombined as Chalicotherium merriami by von Koenigswald (1932).Fossil distribution
- High Rock Canyon, Humboldt County, NevadaHumboldt County, NevadaHumboldt County is a county located in the U.S. state of Nevada. As of 2007, the population was estimated to be 18,052. Its county seat is Winnemucca.The county was the site of an arrest in 2000 that led to the U.S. Supreme Court decision Hiibel v...
, estimated age: ~17.2 Mya. - Virgin Valley, Humboldt County, Nevada, estimated age: ~16.3 Mya.
- Humbug Quarry, Sioux County, NebraskaSioux County, Nebraska-National protected areas:* Agate Fossil Beds National Monument* Nebraska National Forest * Oglala National Grassland -Demographics:...
, ~16.5—16.25 Mya. - Echo Quarry, Sioux County, Nebraska, ~16.3—13.6 Mya.
M. oregonensis
M. oregonsis was named by Leidy 1873. It was named by Leidy (1873) and recombined as Moropus oregonensis by Holland and Peterson (1914) and M. C. Coombs in 1978 and 1998, and also by M. C. Coombs, R. M. Hunt, E. Stepleton, L. B. Albright, III, and T. J. Fremd.Body mass
Two specimens were examined by M. Mendoza, C. M. Janis, and P. Palmqvist for body mass.
- Specimen 1: 58.4 kg (128.7 lb)
- Specimen 2: 90.3 kg (199.1 lb)
Fossil distribution
- Johnson Canyon, John Day FormationJohn Day FormationThe John Day Formation is series of rock strata exposed in the John Day River basin of north-central Oregon in the United States. The strata, which vary in age from 39 million years to 18 million years, were formed mainly from ashfalls from volcanoes to the west...
, Wheeler County, OregonWheeler County, OregonAs of the census of 2000, there were 1,547 people, 653 households, and 444 families residing in the county. The population density was 1 people per square mile . There were 842 housing units at an average density of 0 per square mile...
, estimated age: ~22.2—21.9 Mya. - Rose Creek, John Day Formation, Wheeler County, OregonWheeler County, OregonAs of the census of 2000, there were 1,547 people, 653 households, and 444 families residing in the county. The population density was 1 people per square mile . There were 842 housing units at an average density of 0 per square mile...
- Toledo Bend, Fleming Formation, Newton County, TexasNewton County, TexasNewton County is the easternmost county in the U.S. state of Texas. In of 2000, its population was 15,072. Its county seat is Newton. Newton county is named for John Newton, a veteran of the American Revolutionary War...
, estimated age: 21.9 Mya. - St. Marks RiverLeon County, Florida paleontological sitesThe Leon County paleontological sites are assemblages of Early Miocene invertebrates and vertebrates of Leon County, Florida, United States.-Age:Era: Neogene.Period: Early Miocene...
, Leon County, FloridaLeon County, FloridaLeon County is a county located in the state of Florida, named after the Spanish explorer Juan Ponce de León. At the 2010 Census, the population was 275,487. The county seat of Leon County is Tallahassee which also serves as the state capital. The county seat is home to two of Florida's major...
, estimated age: ~23.1—21.9 Ma. - Buda Mine site, Alachua County, FloridaAlachua County, FloridaAlachua County is a county located in the U.S. state of Florida. The U.S. Census Bureau 2006 estimate for the county is 227,120. Its county seat is Gainesville, Florida. Alachua County is the home of the University of Florida and is also known for its diverse culture, local music, and artisans...
, estimated age: ~23.1—23 Ma.
M. senex
M. sexex was named by Marsh (1877). It was considered a nomen dubiumNomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
by Coombs (1978) and Coombs (1998).