Which group of fossil primates is known for having a dental formula of 2.1.2.3?

The group of fossil primates known for having a dental formula of 2.1.2.3 is the Propliopithecids. This specific dental formula is significant as it indicates a set number of incisors, canines, premolars, and molars, which can provide insights into the dietary habits and evolutionary adaptations of the species.

Propliopithecids, often considered early ancestors of modern catarrhines (which include both Old World monkeys and apes), exhibit traits that display the evolutionary transitions occurring during their time. The dental formula of 2.1.2.3 suggests they might have had a more generalized diet that allowed for a variety of feeding strategies, which could include fruits and possibly leaves.

In contrast, other groups like Oligopithecids, Parapithecids, and Adapids possess different dental formulas that reflect their unique ecological niches and evolutionary paths. The detailed analysis of dental formulas in various primate fossils helps researchers understand how these ancient species related to each other and to modern primates, providing essential insights into primate evolution as a whole.