''Chasicobradys'' is an extinct genus of ground sloths of the family

Nothrotheriidae Nothrotheriidae is a family of extinct ground sloths that lived from approximately 17.5 mya—10,000 years ago, existing for approximately . Previously placed within the tribe Nothrotheriini or subfamily Nothrotheriinae within Megatheriidae, they ...

that lived in what is now

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

. ''Chasicobradys'' was discovered in the

Arroyo Chasicó Formation Arroyo often refers to: * Arroyo (creek), an intermittently dry creek Arroyo may also refer to: People * Arroyo (surname) Places United States ;California * Arroyo Burro Beach, a public beach park in Santa Barbara County, California * Arroyo ...

, in Buenos Aires Province. It is only known from jaw fragments and teeth, which allowed the identification of this species, and was classified as a member of the nothrotheriid subfamily Nothrotheriinae, which comprises small to medium-sized species of ground sloths.

Etymology

The genus name, ''Chasicobradys'', is derived from the

in Argentina and ''bradys'' meaning "slow". was found. The specific name means "intermediate".

Description

''Chasicobradys'' is a medium-sized species, similar in size to the

Argentine Argentines (mistakenly translated Argentineans in the past; in Spanish ( masculine) or ( feminine)) are people identified with the country of Argentina. This connection may be residential, legal, historical or cultural. For most Argentines ...

species '' Neohapalops rothi'', characterized by a very high mandibular ramus and characteristics of its molariform teeth, such as the lack of a diastema between the first and second molars and the oblique location of the fourth molars. ''Chasicobradys'' is one of the few sloths present in the Arroyo Chasicó Formation. Additional remains found in the area suggest the presence of other nothrotheriines along with a genus of megatheriid sloth, '' Anisodontherium''. The remains of these sloths show that at this time the nothrotheriids were already differentiated from the megatheriids and possessed the characteristics that would identify them in later times.

Palaeoecology

The Arroyo Chasicó formation was, in the Miocene, on the tip of a peninsula bordered by the Paranaense Sea. ''Chasicobradys'' would have lived alongside various genera of

Cingulata Cingulata, part of the superorder Xenarthra, is an order of armored New World placental mammals. Dasypodids and chlamyphorids, the armadillos, are the only surviving families in the order. Two groups of cingulates much larger than extant arma ...

, including the last horned armadillo '' Epipeltephilus'', the

Dasypodidae Dasypodidae is a family of mostly extinct genera of armadillos. One genus, ''Dasypus'', is extant, with at least seven living species. __TOC__ Classification Below is a taxonomy of armadillos in this family. Family Dasypodidae *† Genus ...

'' Vetelia'' and '' Chasicotatus'', the

Euphractinae Euphractinae is an armadillo subfamily in the family Chlamyphoridae. Euphractinae are known for having a well developed osteoderm that has large cavities filled with adipose tissue, and more hair follicles with well developed sebaceous glands i ...

Proeuphractus ''Proeuphractus'' is an extinct genus of xenarthran, related to the modern armadillos. It lived from the Early to the Late Miocene, and its fossilized remains were discovered in South America. Description This animal was quite similar to the mo ...

'', the

Glyptodont Glyptodonts are an extinct subfamily of large, heavily armoured armadillos. They arose in South America around 48 million years ago and spread to southern North America after the continents became connected several million years ago. The best-k ...

inae ''

Kelenkura ''Kelenkura'' is an extinct genus of heavily armored mammals belonging to the subfamily Glyptodontinae, from the family Chlamyphoridae that contain most of the modern armadillos. It was a medium-sized South American animal, distantly related to ' ...

'' and the pampathere '' Kraglievichia''. Other

xenarthra Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Ex ...

ns includes several genera of

ground sloths Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. The term is used to refer to all extinct sloths because of the large size of the earliest forms discovered, compared to existing tree sloths. The Cari ...

, such as the

Mylodontidae Mylodontidae is a family of extinct South American and North American ground sloths within the suborder Folivora of order Pilosa, living from around 23 million years ago (Mya) to 11,000 years ago. This family is most closely related to another fa ...

'' Octomylodon'', the

Megalonychidae Megalonychidae is an extinct family of sloths including the extinct '' Megalonyx''. Megalonychids first appeared in the early Oligocene, about 35 million years (Ma) ago, in southern Argentina (Patagonia). There is actually one possible find dati ...

'' Protomegalonyx'', the fellow

'' Xyophorus'', and the

Megatheriidae Megatheriidae is a family of extinct ground sloths that lived from approximately 23 mya—11,000 years ago. Megatheriids appeared during the Late Oligocene (Deseadan in the SALMA classification), some 29 million years ago, in South America. ...

'' Anisodontherium''. Several genera of

rodents Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

were recovered from the formation, such as the earliest genus of

tuco-tucos A tuco-tuco is a neotropical rodent in the family Ctenomyidae.Parada, A., G. D’Elia, C.J. Bidau, and E.P. Lessa. 2011. Species Groups and the Evolutionary Diversification of Tuco-Tucos, genus ''Ctenomys'' (Rodentia: Ctenomyidae). ''Journal of M ...

, maras and

capybaras The capybaraAlso called capivara (in Brazil), capiguara (in Bolivia), chigüire, chigüiro, or fercho (in Colombia and Venezuela), carpincho (in Argentina, Paraguay and Uruguay) and ronsoco (in Peru). or greater capybara (''Hydrochoerus hydro ...

such as '' Cardiomys'', '' Procardiomys'' and '' Cardiatherium'',

Octodontidae Octodontidae is a family of rodents, restricted to southwestern South America. Fourteen species of octodontid are recognised, arranged in seven genera. The best known species is the common degu, ''Octodon degus''. Octodontids are medium-sized ...

such as '' Chasicomys'' and '' Chasichimys'', the

Echimyidae Echimyidae is the family of neotropical spiny rats and their fossil relatives. This is the most species-rich family of hystricognath rodents. It is probably also the most ecologically diverse, with members ranging from fully arboreal to ter ...

'' Pattersomys'', the plain viscacha ''Lagostomus telenkechanum'' and its relative '' Prolagostomus'', and large-sized

Dinomyidae The Dinomyidae are a family of South American hystricognath rodents: the dinomyids were once a very speciose group, but now contains only a single living species, the pacarana. Several of the extinct dinomyids were among the largest rodents kno ...

like '' Carlesia''.

Meridiungulates South American native ungulates, commonly abbreviated as SANUs, are extinct ungulate-like mammals of controversial affinities that were indigenous to South America prior to the Great American Biotic Interchange. They comprise five major groups ...

were also present in the formation, with

Litopterna Litopterna (from grc, λῑτή πτέρνα "smooth heel") is an extinct order of fossil hoofed mammals from the Cenozoic era. The order is one of the five great orders of South American ungulates that were endemic to the continent, until the G ...

genera such as the

Macraucheniidae Macraucheniidae is a family in the extinct South American ungulate order Litopterna, that resembled various camelids. The reduced nasal bones of their skulls was originally suggested to have housed a small proboscis, similar to that of the sa ...

Cullinia ''Cullinia'' is an extinct genus of litoptern, an order of South American native ungulates that included horse-like and camel-like animals such as ''Macrauchenia''. It is only known from fragmentary remains. ''Cullinia levis'' is known from Chas ...

'' and ''

Paranauchenia ''Paranauchenia'' is an extinct genus of South American litopterns belonging to the family Macraucheniidae. It is known only from fossil finds in Argentina. It possessed three toes and long limbs. The species ''Paranauchenia denticulata'' lived i ...

'' and the

Proterotheriidae Proterotheriidae is an extinct family of fossil ungulates from the Cenozoic era that displays toe reduction. Despite resembling primitive, small horses, they were only distantly related to them, and instead belonged to the native South America ...

Neobrachytherium ''Neobrachytherium'' is an extinct genus of proterotheriid mammal from the Late Miocene of Argentina and Uruguay. It is represented by multiple species, including the type ''N. intermedium'', originally named in 1891 by Moreno and Mercerat as a ...

'', while

notoungulates Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resemb ...

were represented by genera such as the large-sized late surviving Homalodotheriidae '' Chasicotherium'', the

Toxodontidae Toxodontidae is an extinct family of notoungulate mammals, known from the Oligocene to the Holocene (11,000 BP) of South America, with one genus, '' Mixotoxodon'', also known from the Pleistocene of Central America and southwestern North Ameri ...

Paratrigodon ''Paratrigodon'' is an extinct genus notoungulate belonging to the subfamily Toxodontinae, containing one species, ''P. euguii''. Like its close relative ''Trigodon'', it is known for the presence of a horn-like protuberance on its forehead. Fos ...

'', the

Interatheriidae Interatheriidae is an extinct family of notoungulate mammals from South America. Interatheriids are known from the Middle Eocene (Mustersan) to the Early Pliocene (Montehermosan).McKenna & Bell, 1997Linares, 2004 These animals were principally ...

Protypotherium ''Protypotherium'' is an extinct genus of notoungulate mammals native to South America during the Oligocene and Miocene epochs. A number of closely related animals date back further, to the Eocene. Fossils of ''Protypotherium'' have been found i ...

'', the Mesotheriidae '' Typotheriopsis'', and the Hegetotheriidae '' Paedotherium'', '' Pseudohegetotherium'' and '' Hemihegetotherium''. The largest

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

were the

Sparassodonta Sparassodonta (from Greek to tear, rend; and , gen. , ' tooth) is an extinct order of carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now thoug ...

'' Pseudolycopsis cabrerai'' and '' Lycopsis viverensis'', and the small

terror bird Phorusrhacids, colloquially known as terror birds, are an extinct clade of large carnivorous flightless birds that were one of the largest species of apex predators in South America during the Cenozoic era; their conventionally accepted tempo ...

Psilopterus ''Psilopterus'' (Greek for "bare wing") is an extinct genus of phorusrhacid ("terror bird") from the Middle Oligocene to possibly the Late Pleistocene of Argentina and Uruguay. Compared to other phorusrhacids, members of the genus are both relat ...

''.

References

{{Taxonbar, from=Q113876373 Prehistoric sloths Prehistoric placental genera Miocene mammals of South America Miocene xenarthrans Neogene Argentina Fossils of Argentina Fossil taxa described in 1987