The mysterious origin of a jamaican monkey extinguished resolved through DNA testing

For nearly 100 years, scientists have been unable to agree on the evolutionary origins of a strange, now extinct, monkey that has lived and thrived in Jamaica for thousands of years. New research suggests that his ancestors arrived from South America and that life on this tropical island has led the species to acquire its strange characteristics.

This extinct Jamaican monkey, called Xenothrix mcgregori, was first discovered by scientists in the 1920s, who found traces of his skull and teeth. Other discoveries since then, including more skulls, leg bones and jaw pieces, suggest a unique species of monkey, known or extinct.

Live in Jamaica, Xenothrix did not have to deal with predators. He had strangely rodent-like legs, relatively few teeth, and a body plan similar to that of lorises. This little monkey was probably a tree-dweller, moving slowly from branch to branch like a shrunken lazy (researchers compare it in size to a Capuchin monkey, whose length does not exceed 12 to 22 inches). This plethora of strange features has led to questions about XenothrixEvolutionists, some experts speculating that it came from a single or unknown branch of ancient New World primates. Scientists, in addition to struggling against its strange morphology, have struggled to get DNA from the bones of these extinct tropical animals; High temperatures and humidity destroy DNA very quickly.

A new research published this week in the Proceedings of the National Academy of Sciences now illuminates the story of this mysterious primate. Genetic analysis of four Xenothrix Specimens found in Jamaican caves suggest that it is closely related to South American titi. The researchers say that these creatures probably arrived in Jamaica by clinging to rafts of floating vegetation. This latest study was conducted by scientists from the Zoological Society of London (ZSL), the Natural History Museum of London (NHM) and the American Museum of Natural History in New York.

Xenothrix It is an "extremely derived titi monkey that has undergone major changes in the body plan" after the arrival and colonization of its new island environment, the researchers wrote.

"The ancient DNA indicates that the Jamaican monkey is in fact only a titi monkey with unusual morphological characteristics, and not an entirely separate branch of the New World monkey," said Ross MacPhee, co-author of the study and scientist at the American Museum of Natural The mammalogy department of history, said in a statement.

The deposits from which these samples were recovered date back relatively recently – 1,400 to 900 years ago – so these creatures probably lived alongside human settlers. Xenothrix, say the researchers, was probably the last living primate in the Caribbean. The research team used a well-known dating technique, called direct acceleration mass spectrometry (AMS), to date the samples. Interestingly, these dates are roughly consistent with the stories of European settlers who described an unknown animal resembling a monkey living on the island.

The genetic analysis suggests the ancestors of Xenothrix Arrivals in Jamaica from South America about 11 million years ago, during the late Miocene. DNA evidence also suggests that the ancestors of Xenothrix arrived on the island several times. According to the researchers, these animals could be hooked to rafts of natural vegetation, which were washed away by the mouths of major rivers of South America. These ancient monkeys were not the only animal in South America to have endured such an aquatic trip. The big existing rodents, called hutias, have probably arrived in the Caribbean islands in the same way.

This study also shows how island environments can dramatically affect the evolutionary trajectory of animals. The islands produced miniature elephants, Hobbit humans, gigantic birds and rats and, in this case, lazy-like primates.

"This new understanding of the evolutionary history of Xenothrix shows that evolution can take unexpected paths when animals colonize islands and are exposed to new environments, "ZSL scientist and researcher Samuel Turvey said in a statement. "However, the extinction of Xenothrix, which has evolved on an island without predators of native mammals, highlights the high vulnerability of single island biodiversity to human impacts. "

Researchers do not know how or why Xenothrix missing, but hunting and habitat loss have probably played a role.

As to deduce the exact appearance of Xenothrixit's more difficult because of the poor fossil record. The researchers say it probably looked like a kinkajou or a night monkey.

Today, titi monkeys still alive are small creatures living in trees that have long, soft red, brown, gray, and black fur. These animals are very vocal and territorial, and are active during the day. Titi monkeys live up to 12 years and fathers often take care of young people.

[Proceedings of the National Academy of Sciences]