It is among other bone remains, notably those of a species of Equus (giant horse) and of a glyptodon (large armadillo), that this jaw was unearthed in the early 1990s in a site dating back to from the Upper Pleistocene (12,000-10,000 BC) in Costa Rica.
Initially, it had been labeled as that of a coyote before being put away in a closet.
Recently, however, researchers have had the chip in the ear.
“It seemed very strange to us that there was a coyote in the Pleistocene.
And when we looked at these bone remains, we started to see characteristics that could be those of a dog, ”says researcher Guillermo Vargas.
An impression confirmed by the visualization of the images of the jaw, by the Mexican biologist and zooarchaeologist Raul Valadez Azua, of the Institute of Anthropological Research of the National Autonomous University of Mexico.
“It could be the oldest dog in the Americas,” says Guillermo Vargas.
So far, the oldest dog fossil on the American continent has been found in Alaska and is dated to 10,000 years ago.
For the moment, the jawbone is kept by the National Museum of Costa Rica and the researchers have received an offer from the University of Oxford to carry out studies on mitochondrial DNA and carbon 14. These would make it possible to obtain more genetic information and determine more precisely the age of the fossil.
In the meantime, this discovery risks reshuffling the cards on current knowledge.
Because who says dog necessarily means the presence of man in this region.
"We have done a lot of research on the history of canines because they are traces of human presence" and when the dog becomes domestic "the jaw changes, the teeth are less sharp, less intended to tear bones and meat" , he adds.
"The first domesticated dogs entered the continent about 15,000 years ago," continues the researcher.
Settlement of the Americas began when humans migrated from Asia through the Bering Strait, located between Siberia and Alaska, when sea levels fell during the last great ice age.
Until now, there was only evidence of human migration to Mexico, Chile or Argentina but not Costa Rica.
"This discovery of the dog would be the first human proof in Costa Rica of a much older period and confirms the theory of human migrations until the settlement of the continent", concludes Guillermo Vargas.