''Xibalbaonyx'' is an extinct genus of

megalonychid 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 dating ...

ground sloth 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 Caribbe ...

known from the

Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division of ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. Three species are known: ''X. oviceps'' and ''X. exiniferis'' from the Yucatan peninsula and ''X. microcaninus'' from

Jalisco Jalisco (, , ; Nahuatl: Xalixco), officially the Free and Sovereign State of Jalisco ( es, Estado Libre y Soberano de Jalisco ; Nahuatl: Tlahtohcayotl Xalixco), is one of the 31 states which, along with Mexico City, comprise the 32 Federal En ...

. The genus is named after

Xibalba (), roughly translated as "place of fright", is the name of the underworld (or quc, Mitnal) in Maya mythology, ruled by the Maya death gods and their helpers. In 16th-century Verapaz, the entrance to Xibalba was traditionally held to be a c ...

, the underworld in

Maya mythology Maya or Mayan mythology is part of Mesoamerican mythology and comprises all of the Maya tales in which personified forces of nature, deities, and the heroes interacting with these play the main roles. The myths of the era have to be reconstructed ...

Discovery and taxonomy

The holotype of ''X. oviceps'' is a mostly complete skeleton discovered in an underwater cave system, while ''X. microcaninus'' being known from a complete skull and mandible from the sediments of the former paleolake of lake Jalisco. The overlapping remains of the skull and mandibles have notable differences between them, enough to call them distinct species. A third species ''X. exiniferis'' was described in 2020, also from an underwater cave in the Yucatan Peninsula, it is known from a "fragmentary left mandibular ramus, an atlas, and a left humerus". In 2020, a description of the postcranial remains of the holotype ''X. oviceps'' was published, suggesting that the taxon had climbing capabilities. In 2021, remains of a form closely related to ''Xibalbaonyx'' was reported from the Pleistocene of Cueva de Iglesitas near

Caracas Caracas (, ), officially Santiago de León de Caracas, abbreviated as CCS, is the capital and largest city of Venezuela, and the center of the Metropolitan Region of Caracas (or Greater Caracas). Caracas is located along the Guaire River in the ...

, Venezuela.

References

{{Taxonbar, from=Q55074742 Prehistoric sloths Pleistocene xenarthrans Prehistoric placental genera Holocene extinctions Rancholabrean Pleistocene Mexico Fossils of Mexico Fossil taxa described in 2017