''Sibotherium'' is an extinct genus of ground sloth in the family

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 ...

that lived in what is now

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

during the Late Miocene. It was a large ground sloth, weighing more than 2,500 kg.

Discovery

Fossils of ''Sibotherium'' have been found in the Curré Formation in the

Puntarenas Province Puntarenas () is a province of Costa Rica. It is located in the western part of the country, covering most of Costa Rica's Pacific Ocean coast, and it is the largest province in Costa Rica. Clockwise from the northwest it borders on the provinces ...

of Costa Rica. The finds are 5.8 million years old and date to the Late Hemphillian, falling within the Late Miocene. The holotype is a left ankle bone. Skeletal parts of some individuals of ''Sibotherium'' have also been found, namely partial mandibles, molars, a collarbone and parts of the legs, hands and feet.

Etymology

The genus name, ''Sibotherium'' is derived from ''Sibö'', the good creator in

Bribri The Bribri are an Indigenous people in eastern Costa Rica and northern Panama. Today, most Bribri people speak the Bribri language or Spanish. There are varying estimates from government officials of the group's population. Estimates of the to ...

mythology, and ''therion'', Greek for "beast". In the beginning Sibö made the Earth, the land, the animals and the plants according to the myths of the Bribri, the original inhabitants of southern Costa Rica. This name was chosen because ''Sibotherium'' was one of the first South American migrants to shape the new faunal composition of Central America. The species name refers to the Bribri word ''Ká'' , which means "place".

Classification

Within the family Megatheriidae, ''Sibotherium'' belongs to the subfamily Megatheriinae. ''Sibotherium'' occupies a basal position within this subfamily and ''Sibotherium'' is most closely related to '' Megathericulus'', '' Pyramiodontherium'' and '' Anisodontherium''. ''Sibotherium'' is the oldest known representative of the Megatheriidae that occurred outside of South America and lived in southern

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

at a time when the Panamanian isthmus was not yet closed, leaving a strait between southern Central America and northwestern Central America. It is believed that ''Sibotherium'' or its ancestor reached southern Central America over a temporary land bridge during a period of sea level decline, tectonic rise or a combination of both.

References

{{Taxonbar, from=Q93943279 Prehistoric sloths Miocene mammals of North America Miocene xenarthrans Neogene Costa Rica Fossils of Costa Rica Hemphillian Fossil taxa described in 2020 Prehistoric placental genera