Nothrotheriops
Encyclopedia
Nothrotheriops is a genus of Pleistocene
ground sloth
found in North
and South America
. This genus of bear-sized xenarthran was related to the much larger, and far more famous Megatherium
, although it has recently been placed in a different family, Nothrotheriidae.
at Aden Crater in New Mexico and was found to still have hair and tendon preserved. This nearly complete specimen is on display at the Yale
Peabody Museum of Natural History in New Haven, Connecticut
. Numerous dung boluses belonging to Nothrotheriops have also been found throughout the southwestern United States and have provided an insight into the diet of these extinct animals.
Although N. shastensis was one of the smallest ground sloth
species, it still reached 2.75 meters from head to tail and weighed 250 kg
(one-quarter of a tonne) - much smaller than some of its contemporary species such as the Eremotherium
, which could easily weigh over two tons and be 6 meters long. It had large, stout hindlegs and a powerful, muscular tail that it used to form a supporting tripod whenever it shifted from a quadrupedal stance to a bipedal one (i.e. Eremotherium
).
s, feeding on various plants like the Desert Globemallow
, cacti
, and yucca
. It was hunted by various local predators, like the Smilodon
, from which the sloths may have defended themselves by standing upright on hindlegs and tail and swiping with their long foreclaws, like its distant relative Megatherium
, as conjectured in the BBC series Walking with Beasts
. The same claws could also been used as tools to reach past the plant spines and grab softer flowers and fruits. Also, the Shasta ground sloth may have had a prehensile tongue (like a giraffe
) to strip leaves off branches.
This species' ancestry dates back to the Miocene
. Shasta ground sloths migrated to North America from South America during the Irvingtonian
about 1 MYA. This species' range came as far north as the Canadian province of Alberta
, making it one of the most northerly species of its clan, which otherwise lived primarity in the southern region of the North American continent, i.e. the states Texas
, South Carolina
and Florida
.
The best known historical specimen was found in a lava tube
at Aden Crater in New Mexico; it was found with hair and tendon still preserved. Also, prolonged period of search at Rampart Cave have revealed a plentiful amount of the sloth's hair and dung, which allowed the scientists both to use radiocarbon dating
techniques to establish when it lived.
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
ground sloth
Ground sloth
Ground sloths are a diverse group of extinct sloths, in the mammalian superorder Xenarthra. Their most recent survivors lived in the Antilles, where it has been proposed they may have survived until 1550 CE; however, the youngest AMS radiocarbon date reported is 4190 BP, calibrated to c. 4700 BP...
found in North
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...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. This genus of bear-sized xenarthran was related to the much larger, and far more famous Megatherium
Megatherium
Megatherium was a genus of elephant-sized ground sloths endemic to Central America and South America that lived from the Pliocene through Pleistocene existing approximately...
, although it has recently been placed in a different family, Nothrotheriidae.
Discovery and species
Fossils of the best-known species, the Shasta ground sloth (N. shastensis), have been found throughout western North America, especially in the American Southwest. The most famous specimen was recovered from a lava tubeLava tube
Lava tubes are natural conduits through which lava travels beneath the surface of a lava flow, expelled by a volcano during an eruption. They can be actively draining lava from a source, or can be extinct, meaning the lava flow has ceased and the rock has cooled and left a long, cave-like...
at Aden Crater in New Mexico and was found to still have hair and tendon preserved. This nearly complete specimen is on display at the Yale
Yale University
Yale University is a private, Ivy League university located in New Haven, Connecticut, United States. Founded in 1701 in the Colony of Connecticut, the university is the third-oldest institution of higher education in the United States...
Peabody Museum of Natural History in New Haven, Connecticut
New Haven, Connecticut
New Haven is the second-largest city in Connecticut and the sixth-largest in New England. According to the 2010 Census, New Haven's population increased by 5.0% between 2000 and 2010, a rate higher than that of the State of Connecticut, and higher than that of the state's five largest cities, and...
. Numerous dung boluses belonging to Nothrotheriops have also been found throughout the southwestern United States and have provided an insight into the diet of these extinct animals.
Although N. shastensis was one of the smallest ground sloth
Ground sloth
Ground sloths are a diverse group of extinct sloths, in the mammalian superorder Xenarthra. Their most recent survivors lived in the Antilles, where it has been proposed they may have survived until 1550 CE; however, the youngest AMS radiocarbon date reported is 4190 BP, calibrated to c. 4700 BP...
species, it still reached 2.75 meters from head to tail and weighed 250 kg
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
(one-quarter of a tonne) - much smaller than some of its contemporary species such as the Eremotherium
Eremotherium
Eremotherium is an extinct genus of actively mobile ground sloth of the family Megatheriidae, endemic to North America and South America during the Pleistocene epoch...
, which could easily weigh over two tons and be 6 meters long. It had large, stout hindlegs and a powerful, muscular tail that it used to form a supporting tripod whenever it shifted from a quadrupedal stance to a bipedal one (i.e. Eremotherium
Eremotherium
Eremotherium is an extinct genus of actively mobile ground sloth of the family Megatheriidae, endemic to North America and South America during the Pleistocene epoch...
).
Ecology
Nothrotheriops shastensis behaved like all typical ground sloths of North and South AmericaSouth America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
s, feeding on various plants like the Desert Globemallow
Sphaeralcea ambigua
Sphaeralcea ambigua, commonly known as Desert Globemallow or Apricot Mallow, is a member of the genus Sphaeralcea in the mallow family ....
, cacti
Cactus
A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...
, and yucca
Yucca
Yucca is a genus of perennial shrubs and trees in the family Asparagaceae, subfamily Agavoideae. Its 40-50 species are notable for their rosettes of evergreen, tough, sword-shaped leaves and large terminal panicles of white or whitish flowers. They are native to the hot and dry parts of North...
. It was hunted by various local predators, like the Smilodon
Smilodon
Smilodon , often called a saber-toothed cat or saber-toothed tiger, is an extinct genus of machairodonts. This saber-toothed cat was endemic to North America and South America, living from near the beginning through the very end of the Pleistocene epoch .-Etymology:The nickname "saber-tooth" refers...
, from which the sloths may have defended themselves by standing upright on hindlegs and tail and swiping with their long foreclaws, like its distant relative Megatherium
Megatherium
Megatherium was a genus of elephant-sized ground sloths endemic to Central America and South America that lived from the Pliocene through Pleistocene existing approximately...
, as conjectured in the BBC series Walking with Beasts
Walking with Beasts
Walking with Beasts is a 2001 six-part television documentary miniseries, produced by the BBC in the United Kingdom, narrated by Kenneth Branagh. In North America it has been retitled Walking with Prehistoric Beasts, and the original Discovery Channel broadcast was narrated by Stockard Channing...
. The same claws could also been used as tools to reach past the plant spines and grab softer flowers and fruits. Also, the Shasta ground sloth may have had a prehensile tongue (like a giraffe
Giraffe
The giraffe is an African even-toed ungulate mammal, the tallest of all extant land-living animal species, and the largest ruminant...
) to strip leaves off branches.
This species' ancestry dates back to 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...
. Shasta ground sloths migrated to North America from South America during the Irvingtonian
Irvingtonian
The Irvingtonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 1,800,000 to 300,000 years BP, a period of . It is usually considered to overlap the Lower Pleistocene and Middle...
about 1 MYA. This species' range came as far north as the Canadian province of Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, making it one of the most northerly species of its clan, which otherwise lived primarity in the southern region of the North American continent, i.e. the states Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
and Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
.
The best known historical specimen was found in a lava tube
Lava tube
Lava tubes are natural conduits through which lava travels beneath the surface of a lava flow, expelled by a volcano during an eruption. They can be actively draining lava from a source, or can be extinct, meaning the lava flow has ceased and the rock has cooled and left a long, cave-like...
at Aden Crater in New Mexico; it was found with hair and tendon still preserved. Also, prolonged period of search at Rampart Cave have revealed a plentiful amount of the sloth's hair and dung, which allowed the scientists both to use radiocarbon dating
Radiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
techniques to establish when it lived.
Further reading
- Naples, Viriginia L. (1987), Reconstruction of Cranial Morphology and Analysis of Function in the Pleistocene Ground Sloth Nothrotheriops shastense (Mammalia, Megatheriidae), Contributions in Science 389, October 1987, Natural History Museum of Los Angeles County
- Schmidt, Gerald D.; Duszynski, Donald W.; Martin, Paul S. (1992), Parasites of the Extinct Shasta Ground Sloth, Nothrotheriops shastensis, in Rampart Cave, Arizona, J. Parasitol., 78(5), 1992, p. 811-816, American Society of Parasitologists
- Steadman et al. (2005). Asynchronous extinction of late Quaternary sloths on continents and islands, PNAS,