Haramiyida

Haramiyida Temporal range: Late Triassic-Late Cretaceous, 216.5–65 Ma PreЄ Є O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Order:	Therapsida
Suborder:	Cynodontia
Clade:	Mammaliaformes
Clade:	†Haramiyida Hahn, Sigogneau-Russell & Wouters, 1989
Subgroups
†Haramiyoidea †Haramiyidae †Haramiya †Haramiyaviidae †Haramiyavia †Kirtlingtonia †Millsodon †Avashishta †Hahnodontidae †Theroteinida †Theroteinidae †Theroteinus †Euharamiyida †Eleutherodon †Sineleutherus †Arboroharamiya †Shenshou †Xianshou

Haramiyidans seem to be the earliest known herbivores amongst basal mammals. Their teeth, which are by far the most common remains, resemble those of the multituberculates. However, based on Haramiyavia, the jaw is less derived; and at the level of evolution of earlier basal mammals like Morganucodon and Kuehneotherium, with a groove for ear ossicles on the dentary. They are the longest lived mammalian clade of all time. However, a more recent study, in November 2015, may dispute this and suggested the Haramiyida were not mammals after all, but were part of a more ancestral side branch instead.

Haramiyids show certain similarities to multituberculates, a group of mammals that survived until about 40 million years ago. It is possible that haramiyids are ancestral to multituberculates, although the available evidence is insufficient to be conclusive. Certain characteristics of the teeth seem to rule out a special relationship between the two groups, although some studies still unite haramiyids (or at least euharamiyids) and multituberculates in the Allotheria hypothesis.

For a long time it was unknown if haramiyids were crown-group mammals, or if they should be placed in the stem-group Mammaliaformes. This uncertainty stems from the fact that haramiyid remains were mostly restricted to teeth and jaw fragments. However, new discoveries of much more complete haramiyid fossils have settled the issue—haramiyids are undoubtedly crown-group mammals. For example, the specimens show evidence of a typical mammalian middle ear, the area just inside the eardrum that turns vibrations in the air into ripples in the ear's fluids. The middle ears of mammals are unique in that they have three bones, as evidenced in the new fossils.

Order †HaramiyidaHahn, Sigogneau-Russell & Wouters 1989 [Haramiyoidea Hahn 1973 sensu McKenna & Bell 1997]

Haramiyids seem to have generally been herbivorous or omnivorous, possibly the first mammalian herbivores; however, the sole haramiyid tested in a study involving Mesozoic mammal dietary habits, Haramiyavia, ranks among insectivorous species. At least some species were very good climbers and were similar to modern day squirrels; and several others have more recently been reassessed as possibly arboreal. General arboreal habits might explain their rarity in the fossil record.

...
Wikipedia