Which group of early anthropoid primates is considered to be the earliest, dating to about 35 million years ago?

The earliest group of anthropoid primates dating to about 35 million years ago is the Oligopithecids. This group is significant in primate evolution as they are considered to be among the first true monkeys, showcasing characteristics that are key in the transition from earlier primates to more modern forms. Oligopithecids exhibit features that suggest they were adapted to life in the trees, highlighting the evolutionary shift towards an arboreal lifestyle.

Their fossils have provided valuable insights into the morphological changes occurring at this time, as well as clues about their ecological adaptations. Studying the Oligopithecids allows researchers to understand the origins of various traits seen in later primate species, making them a crucial part of primate evolutionary history.