A team of cave divers and scientists have discovered a new treasure trove of extinct monkey fossils deep in the underwater passages of a Caribbean cave. Forty years ago, only a few well-preserved remains of New World monkeys were found on the Caribbean islands of Hispaniola and Jamaica, but that was enough to point to a missing piece of primate evolutionary history.

One of these fossil species was the Hispaniola monkey (Antillothrix bernensis), known only from the ankle bone and a few fragments of the broken jaw.

But with advances in cave diving safety and technology, researchers began exploring the islands’ deeper submerged cave systems in 2009, and the first skull was found in 2011. A. Bernensis. Important to the indigenous Taino people, these underwater caves are full of “extremely well-preserved” fossils that have been there for thousands of years, protected from waves and animals.

Recent discoveries in the Cueva Macho cave system on the island of Hispaniola in the Dominican Republic add new details to our understanding of extinct species.

“The quantity and quality of the skull antillothrix“What’s described in this paper allows us to fully describe the skull and understand the differences between individuals,” says Johns Hopkins University paleobiologist Siobhan Cook. “This could give us information about the nutrition and social systems of these animals.”

Four new skulls were found in the cave, along with three new jawbones. These new pieces from the Cueva Macho system, as well as an adult jawbone found in a similar cave called Padre Nuestro, and the entire species Antillothrix bernensis It is now represented by seven nearly complete skull boxes, two upper jaw fragments, one posterior head fragment, and five complete skull fragments. dozens of other bones outside the lower jaw and skull.

It doesn’t seem like much, but this collection, especially the skulls, goes a long way in describing the apes’ size, diet, sexual differences, and even social life. And that’s more detail than we have for other Caribbean monkeys.

“These new samples, combined with those previously described, will allow detailed examination of population and species-level diversity, an extremely rare opportunity for any fossil primate,” the authors write in their paper.

Researchers studying the fossils estimate that males and females were about the same size, weighing up to 3.4 kilograms (about 7 pounds); This suggests that mating was not overly competitive and they may have lived in small, monogamous family groups with offspring. depending on their parents.

Their round teeth with small canines would have been suitable for a fruit-based diet similar to the modern diet.
South American titi monkeys with similar physical characteristics. They also do not appear to have wisdom teeth, which are rare among primates. How these monkeys got into the caves all those years ago is a mystery, but based on the damage to the jaw fossils, Cook suspects it wasn’t by choice.

“It’s possible that a large enough extinct owl could capture these monkeys and bring them back to the cave where they lived, rather than the monkeys randomly reaching there,” he says. “It is not uncommon for owl bait to accumulate in Spanish caves.”

The Hispaniola monkey became extinct within the last 10,000 years, but it is unclear exactly what gave rise to this species.

“These fossils help us understand anatomy better.” antillothrixIt can help us identify environmental factors that may lead to extinction… [і] Ultimately, it guides policies to preserve remaining mammal diversity in the Caribbean and elsewhere,” says Cook.

This study was published on: Journal of Human Evolution.