Euharamiyida also known as Eleutherodontida, is
clade of early
mammals or mammal-like
cynodonts from the Middle Jurassic to Early Cretaceous of Eurasia and possibly North America. The group is sometimes considered a
sister group to
Multituberculata,[1] or part of an earlier divergence within the
synapsid line.[2][3] It is disputed whether or not they are related to the Haramiyids from the Late Triassic, such as Haramiyavia.[4] The morphology of their teeth indicates that they were herbivorous or omnivorous. Some members of the group are known to be
arboreal, including gliding forms similar to modern
flying squirrels or
colugos.[1][5]
Evolution
The position of euharamyidans is contested. They are either considered crown group mammals as members of
Allotheria, related to
multituberculates, or they are considered to stem-group mammals within the
Mammaliaformes.[1][3] The position is often dependent on the relationships of euharamiyids to the Late Triassic haramiyids such as Haramiyavia and
Thomasia. In some studies, the two groups are recovered as unrelated.[6][4]
^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.
^
abMao, Fangyuan; Brewer, Philippa; Hooker, Jerry J.; Meng, Jin (2022). "New allotherian specimens from the Middle Jurassic Woodeaton Quarry (Oxfordshire) and implications for haramiyidan diversity and phylogeny". Journal of Systematic Palaeontology. 20: 1–37.
doi:
10.1080/14772019.2022.2097021.
S2CID251708147.