DNA of ‘bizarre’ extinct Jamaican monkey traced back to unexpected origin

13 Nov 2018

The titi monkey is a distant relative of Xenothrix. Image: © llaurent789/Stock.adobe.com

The lineage of a now extinct monkey in Jamaica – with features totally different from many of its relatives – has been traced back to South America.

For years, a now extinct monkey that lived in Jamaica has perplexed scientists due to its body characteristics being significantly different than any other living monkey. Called Xenothrix, the slow-moving tree-dweller had only a small number of teeth, with leg bones similar to a rodent.

This bizarre combination begged the question as to what its ancestors were and how it could have evolved on the island. Now, research published to the Proceedings of the National Academy of Sciences by a team made up of researchers from the Zoological Society of London, London’s Natural History Museum and the American Museum of Natural History in New York may have an answer.

After recovering the first ever ancient DNA from Xenothrix bones found in a cave, the team is able to say with confidence that the monkey colonised Jamaica from South America 11m years ago. As for how the monkeys got here, the team predicts that they could have floated across the Caribbean Sea on natural rafts of vegetation washed out of the mouths of large South American rivers.

‘Evolution can act in unexpected ways’

This forced migration is also the likely answer for why a number of other animals – including large rodents called hutias – arrived to the islands and still survive today.

“This new understanding of the evolutionary history of Xenothrix shows that evolution can take unexpected paths when animals colonise islands and are exposed to new environments,” said Prof Samuel Turvey, co-author of the study.

“However, the extinction of Xenothrix, which evolved on an island without any native mammal predators, highlights the great vulnerability of unique island biodiversity in the face of human impacts.”

As for its ancestors, the DNA analysis revealed that the Jamaican monkey is actually just a titi monkey with some additional features, rather than a whole new branch of monkey.

Another co-author of the study, Ross MacPhee, added: “Evolution can act in unexpected ways in island environments, producing miniature elephants, gigantic birds and sloth-like primates. Such examples put a very different spin on the old cliché that ‘anatomy is destiny’.”

Colm Gorey was a senior journalist with Silicon Republic