A 1978 dig in Nacaome, northeast Costa Rica, found bone remains from the Late Pleistocene.
Excavations began in the 1990s and produced the remains of a giant horse, Equus sp, a glyptodon (a large armadillo), a mastodon (an ancestor of the modern elephant) and a piece of jaw from what was originally thought to be a coyote skull.
The coyote is a relative of the domestic dog, although with a different jaw and more pointed teeth.
Humans are believed to have emigrated to the Americas across the Bering Strait from Siberia to Alaska during the last great ice age.
The presence of humans during the Pleistocene has been attested in Mexico, Chile and Patagonia, but never in Central America, until now.
This could be the oldest dog in the America.
So far, the oldest attested dog remains were found in Alaska and are 10,150 years old.
Oxford University has offered to perform DNA and carbon dating tests on the sample to discover more genetic information about the animal and its age.
The fossil is currently held at Costa Rica’s national museum but the sample cannot be re-identified as a dog without validation by a specialist magazine.