Four complete skulls and jaws of a species extinct in America, Arctotherium, that lived during the Pleistocene and disappeared 11,300 years ago, were found by sub aquatic archaeologists in the bed of a cenote in the Yucatan Peninsula, Mexico.

These are the only specimens of their type found until now in this region of the country, and add up to the list of Prehistorical fauna located inside this kind of water bodies, which before glaciations were dry caves.

Sub aquatic archaeologist Guillermo de Anda Alanis, from the Yucatan Autonomous University (UADY), who conducts this research as part of the project authorized by the National Institute of Anthropology and History (INAH) “El Culto al Cenote en el Centro de Yucatan” (Cult to Cenote in Central Yucatan) since 2007, announced the details of the discovery at the International Congress American Cultures and their Environment: Perspectives from Zoo Archaeology, Paleo Botanic and Ethno Biology, organized by UADY and taking place from November 1st to 5th 2010 in Merida, Yucatan.

Guillermo de Anda Alanis declared that the remains were located in a submerged cavern between the towns of Sotuta and Homun, in Yucatan, at 40 meters depth. Bones were dispersed in a 120 meter diameter surface, and it has been estimated that they could correspond to a family of bears, since the 2 adult skulls belonged to a male and a female, while the other 2 skulls did not reach their full development. They were all from the same species.

The archaeologist indicated that besides the mammals’ remains, 5 ancient human bone remains, still to be dated, were located 30 meters away from the bears, but it is still unknown if they are related.

After several studies performed In Situ and analysis of the photographs, De Anda noticed that the form of the bones and skulls had not been observed among fauna in other archaeological contexts; “these are the only remains of bears located at the Yucatan Peninsula, being the nearest reference located in a cave at Belize. Apparently it was an Ornatus bear. Other specimens were located in Brazil and Argentina. In Mexico, their habitat has been identified in the center and north of the country”.

Archaeozoologist Christopher Gotz from UADY conducted the morphological identification of the remains, determining they belonged to bears since their molars were strong, flat and wide.

De Anda explained that at first the remains were thought to have belonged to jaguars, but the form of molars and premolars as well as the size of the skulls determined they were not felines.

He commented that the species has not been defined yet. “The next step is to define their genus comparing the remains with the list of bears in America. There are 2 sub families, the one of common bears such as the grizzly, being the other the short faced one, from which there is one species left, the Andean from Venezuela. The discovered remains are part of the last sub family.

Arctotherium genus includes several bear species, all of them extinct and endemic of South America. If the discovered remains turn out to be of this species, it would change perspectives regarding bio geography and migration of American bears, since specimens of that affiliation have not been found in Central America. Until laboratory results are ready, these are still hypotheses.

A theory points out that this bear genus might have migrated to America thousands of years ago and might have crossed Central America, but there are not vestiges to verify this, or else, they were endemic of South America.

Archaeozoologist Gotz declared that species related to Arctotherium in America are extinct North American short-faced bears(Arctodus simus and pristinus); Florida short-faced (Tremarctos floridanus; Mexico short-faced (Tremarctos mexicanus) and the last survivor that dwells in South America, the Andean short-faced bear (tremarctos ornatus).

More in situ studies must be conducted before the remains’ extraction. “This research is only beginning, and it will most likely provide important data for the knowledge of the first species that inhabited the region, as well as of the historical periods to which human remains yet to be analyzed belong.

“We are looking forward to confirm after analysis that the remains correspond to that genus, since it would enlarge the knowledge regarding this animal’s natural history and their relation with their closer relatives” concluded De Anda.