Dental fossils fill a 6 million year gap in primate evolution

Researchers have used fossilized teeth discovered near Lake Turkana, in northwestern Kenya, to identify a new species of monkey, a finding that helps fill a 6 million year gap in the world. evolution of primates.

Terry Spell, UNLV geoscientist, and Dawn Reynoso, a former master's student, were part of the international research team that discovered the species that lived there 22 million years ago. ; years. Understanding the evolution of ancient world monkeys is important because, with great apes and humans, they belong to the anthropoid group of primates, primates resembling humans.

According to Spell, the discovery of the fossil monkey stems from a further study of a section of sedimentary rocks in Kenya that contains a large number of different types of fossils, including several hundred jaws, limbs and mammalian teeth. and reptiles.

Previous studies had documented the early evolution of Old World monkeys using fossils dated 19 million and 25 million years ago, leaving an interval of 6 million of years in the first recording. However, it was determined that the new fossil was 22 million years old. The isotopic ages on rocks were obtained at the Nevada Isotope Geochronology Laboratory on the UNLV campus.

"This adds to our understanding of the oldest evolutionary history of Old World monkeys, including changes in their diet over time to include more leaves," Spell said. "The monkeys were born at a time when Africa and Arabia formed an island continent, tectonic movements of the plates pushed this continental mass into the Eurasian landmass there are 20 to 24 million Years, and an exchange of animals and plants took place.It is unclear whether competition with newly introduced species or changing climatic conditions have resulted in changes in the diet. "

Scientists have named the newly discovered monkey species Alophia ("without lophs") because of the lack of molar ridges on the teeth – a phenomenon that distinguishes them from geologically younger monkey fossils.

The Old World monkeys are the most successful living superfamily of non-human primates, with a geographical distribution surpassed only by humans. The group occupies a wide range of habitats ranging from land to trees and has a diverse range of diets. They have evolved to develop a characteristic dental characteristic, namely two molar ridges, which allows them today to treat a wide variety of types of foods found in various African and Asian environments. ;Asia.

"Old World primitive monkey dating from the early Miocene of Kenya and the evolution of cercopithecoid bilophodontia" was published in Proceedings of the National Academy of Sciences.