Order Haramiyida—“Primates” of the Mesozoic

The first representatives of the order Haramiyida (Allotheria, Mammalia) appeared in the Late Triassic. Their morphology differed in a number of plesiomorphic features. For instance, their lower jaw retained a ridge of Meckelian cartilage and a double articulation with the skull, a small crown bone os coronare, etc. Haramiyidans experienced a large adaptive radiation in the Late Middle and early Late Jurassic. During that period, they became widespread. At the end of the Jurassic, most of the Haramiyidan genera began to die out. However, some members of the order existed until the middle Cretaceous. The morphology of the skeleton indicates that Haramiyida lived mainly in trees. Some of them had a lateral skin fold that allowed them to glide. However, there were also terrestrial forms, such as Megaconus. The structure of the skull and the teeth suggests that Haramiyida were carnivorous animals, and fed mainly on insect larvae. In Jurassic communities, Haramiyidans occupied an ecological niche similar to Paleocene plesiadapids, some modern lemurs in Madagascar, and monkeys of the family Callitrichidae in South America.