Euharamiyida also known as Eleutherodontida, is

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

of early

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s or mammal-like

cynodont The cynodonts () (clade Cynodontia) are a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 mya), and extensively diversified after the Permian–Triassic extinction event. Cynodonts had a wide variety ...

s from the Middle Jurassic to Early Cretaceous of Eurasia and possibly North America. The group is sometimes considered a

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

Multituberculata Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, a ...

, or part of an earlier divergence within the

synapsid Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes reptil ...

line. It is disputed whether or not they are related to the Haramiyids from the Late Triassic, such as ''

Haramiyavia ''Haramiyavia'' ("thief grandmother" from Arabic الحرامية (al ḥarāmiyah), "thief, ''Haramiya''" + Latin avia, "grandmother") is a genus of synapsid in the clade Haramiyida that existed about 200 million years ago in the Rhaetian stage ...

''. The morphology of their teeth indicates that they were herbivorous or omnivorous. Some members of the group are known to be

arboreal Arboreal locomotion is the Animal locomotion, locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. Th ...

, including gliding forms similar to modern

flying squirrels Flying squirrels (scientifically known as Pteromyini or Petauristini) are a tribe of 50 species of squirrels in the family Sciuridae. Despite their name, they are not in fact capable of full flight in the same way as birds or bats, but they ar ...

colugos Colugos () are arboreal gliding mammals that are native to Southeast Asia. Their closest evolutionary relatives are primates. There are just two living species of colugos: the Sunda flying lemur (''Galeopterus variegatus'') and the Philippine ...

Evolution

The position of euharamyidans is contested. They are either considered crown group mammals as members of

Allotheria Allotheria (meaning "other beasts", from the Greek , '–other and , '–wild animal) is an extinct branch of successful Mesozoic mammals. The most important characteristic was the presence of lower molariform teeth equipped with two longitudin ...

, related to

multituberculates Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, ...

, or they are considered to stem-group mammals within the

Mammaliaformes Mammaliaformes ("mammalian forms") is a clade that contains the crown group mammals and their closest Extinction, extinct relatives; the group adaptive radiation, radiated from earlier probainognathian cynodonts. It is defined as the clade origin ...

. The position is often dependent on the relationships of euharamiyids to the Late Triassic haramiyids such as ''

'' and ''Thomasia''. In some studies, the two groups are recovered as unrelated.X.-Z. Luo, Q.-J. Meng, D. M. Grossnickle, D. Lui, A. I. Neander, Y.-G. Zhang, and Q. Ji. 2017. New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem. Nature 548:326-329.

Phylogeny

Taxa

The following taxonomy follows Mao et al. (2022) unless otherwise cited. * '' Cryoharamiya'' * ''

Maiopatagium ''Maiopatagium'' ("greater patagium" from Latin maius, “greater, larger” + Modern Latin patagium, “ patagium”) is an extinct genus of gliding euharamiyids which existed in Asia during the Jurassic period. It possessed a patagium between ...

'' * '' Millosodon'' * '' Sharypovoia'' * ''

Sineleutherus ''Sineleutherus'' is an extinct genus of euharamiyids which existed in Asia during the Jurassic period. The type species is ''Sineleutherus uyguricus'', which was described by Thomas Martin, Alexander O. Averianov and Hans-Ulrich Pfretzschner i ...

'' * '' Woodeatonia'' * ?'' Allostaffia'' * ?

Hahnodontidae Hahnodontidae is a family of extinct mammaliaforms from Early Cretaceous deposits in Morocco and the Western United States. Although originally considered to belong to the extinct clade Multituberculata, recent work indicates that hahnodontids ...

Sigogneau-Russell, 1991 * ?''

Megaconus ''Megaconus'' is an extinct genus of allotherian mammal from the Middle Jurassic Tiaojishan Formation of Inner Mongolia, China. The type and only species, ''Megaconus mammaliaformis'' was first described in the journal ''Nature'' in 2013. ''Meg ...

'' * ?

Gondwanatheria Gondwanatheria is an extinct group of mammaliaforms that lived in parts of Gondwana, including Madagascar, India, South America, Africa and Antarctica during the Upper Cretaceous through the Paleogene (and possibly much earlier, if '' Allostaff ...

* Arboroharamiyidae Zheng ''et al.'', 2013 ** ''

Arboroharamiya ''Arboroharamiya'' ("tree thief" from Latin arbor, "tree" + Arabic الحرامية (al ḥarāmiyah), "thief, '' Haramiya''") is an extinct genus of early mammal (or possibly a non-mammalian mammaliaform) from the Middle Jurassic Tiaojishan Fo ...

'' ** ''

Vilevolodon ''Vilevolodon'' is an extinct, monotypic genus of volant, arboreal euharamiyids from the Oxfordian age of the Late Jurassic of China. The type species is ''Vilevolodon diplomylos''. The genus name ''Vilevolodon'' references its gliding capabili ...

'' ** ''

Xianshou ''Xianshou'' is a genus of glidingQing-Jin Meng; David M. Grossnickle; Di Liu; Yu-Guang Zhang; April I. Neander; Qiang Ji; Zhe-Xi Luo (2017). "New gliding mammaliaforms from the Jurassic". Nature. in press. . haramiyidan synapsid known from the ...

'' * Kermackodontidae Butler and Hooker, 2005 (="Eleutherodontidae" Kermack et al., 1998) (considered by other studies to be multituberculates) ** '' Kermackodon'' ** '' Butlerodon'' * Shenshouidae Mao and Meng, 2019 ** '' Qishou'' ** '' Shenshou''

References

{{Taxonbar, from=Q18231220 Jurassic first appearances Jurassic extinctions Taxa named by Shundong Bi Taxa named by Yuanqing Wang Taxa named by Xia Sheng Taxa named by Jin Meng