Haramiyidans were a long lived lineage of mammaliaform cynodonts or 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. If they are early multituberculates, they would be 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 crown mammals, but were part of an earlier offshoot of mammaliaformes instead.
Relationships
Haramiyids show certain similarities to multituberculates, a group of mammals that survived until about 40million 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 and multituberculates in the Allotheria hypothesis. Most recently, haramiyidans have been found to be a monophyletic group of non-mammalian Mammaliaformes. In this study, gondwanatheres – usually interpreted as mammals, and derived multituberculates in particular – have been found to be deeply nested among them.
Taxonomy
Order †Haramiyida Hahn, Sigogneau-Russell & Wouters 1989
* ?†Allostaffia aenigmatica Heinrich 2004 ; possible gondwanathere instead.
* †Thomasia Poche 1908
** †T. woutersi Butler & MacIntyre 1994
** †T. hahni Butler & MacIntyre 1994
** †T. moorei Butler & MacIntyre 1994
** †T. antiqua Poche 1908
In May 2018, a new genus and species was named, and is believed to be a member of Hahnodontidae:
†Cifelliodon wahkarmoosuch'' Huttenlocker et al. 2018
Lifestyle
Haramiyids seem to have generally been herbivorous or omnivorous, possibly the first mammalian herbivores; however, the sole haramiyid tested in a study involving Mesozoic mammaldietary 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. Several haramiyidans, Maiopatagium, Xianshou, Vilevolodon and Arboroharamiya, took it one step further and developed the ability to glide, having extensive membranes similar to those of modern colugos. In many of these taxa, the coracoid bones are remarkably large and similar to those of birds and pterosaurs, presumably due to impact stresses at landing. Mammalian toothmarks on dinosaur bones may belong to Sineleutherus, suggesting that some haramiyidans scavenged on dinosaur remains.
Range
Most fossils have been reported from Europe, but some are known from Africa and Greenland. Since 2005, the published range extended to Mongolia and China. The age of haramiyid fossils range from Upper Triassic up to Late Cretaceous. This has important implications: the fact that haramiyids were present in the Late Triassic supports the idea that crown-group mammals originated at least 208 million years ago, much earlier than some previous research suggests. The youngest haramiyid fossil genus is Avashishta bacharamensis from the Maastrichtian of India. Cretaceous haramiyids are previously known from the Early Cretaceous of Morocco, suggesting that these animals may have survived in gondwannan landmasses as relics; the presence of the similarly aged Cifelliodon in North America suggests that contact between both landmasses remained for a while. With a temporal range of at least 150 million years, they are the longest lived mammaliaform lineage.
