In an October 2013 study, researchers described an ancient, tiny primate that was found in a Thai coal mine. The new discovery comes from a pivotal period in primate evolution about 35 to 40 million years ago, when simians migrated across a sea from Asia to Africa.
Coal mine finds
The Krabi coal mines in Thailand have provided a rich trove of fossils over several decades, including two fossils of anthropoids, a group that includes all monkeys and apes, including humans.
The history of anthropoids has been shrouded in mystery. Scientists have found fossils of some of the earliest primates, such as the miniscule Archicebus achilles pictured here, from about 55 million years ago in China, and fossils of anthropoids, the precursors to monkeys and men, about 45 million years old in Southeast Asia.
By around 38 million years ago, anthropoid fossils are found in Libya. That suggests ancient primates somehow traveled from Asia to Africa, a daunting feat when the two continents were separated by the vast Tethys Sea. Exactly how they did that was a mystery.
The team unearthed part of the jaw and teeth of the new species, Krabia minuta. Krabia dates from roughly the time of primate's migration to Africa. The tiny animals weighed just 0.5 pounds .
Gum and fruits
The pint-sized primates were much smaller than any of the known related species. Their teeth, shown here in a computed tomography (CT) scan, were also strange, more adapted to eating fruit and gummy foods than nuts or insects as their close relatives did.
The new species has for now been placed on the primate family tree with creatures known as amphipithecids, but a more complete fossil may be needed to make a definitive classification, researchers say.