Didactylus

Didactylus is a genus of fossil mammals that lived during the Oligocene epoch in South America. These early ungulates, meaning hoofed mammals, are known from fossil remains discovered in Argentina. The name Didactylus itself means "two fingers," referring to a characteristic feature of its forelimbs, which had only two well-developed digits. This anatomical trait is a key distinguishing factor from other related mammal groups.

The classification of Didactylus has been subject to some debate among paleontologists. It is often placed within the extinct order Xenungulata, a group of South American mammals whose evolutionary relationships are not fully understood. Xenungulates are characterized by their large size and distinctive dental and skeletal features. Didactylus, while not as massive as some other xenungulates, shares these general characteristics.

The fossil evidence suggests that Didactylus was a herbivore, likely feeding on vegetation available in its Oligocene environment. Its relatively small size compared to some other xenungulates might indicate a different ecological niche or a younger evolutionary stage within the group. The discovery of Didactylus has contributed to our understanding of the diversity and evolution of mammals in South America during a crucial period of mammalian radiation following the extinction of the dinosaurs. Further research on its skeletal anatomy and comparative studies with other fossil mammals continue to refine our knowledge of this ancient creature.