Ankhurida Thuy, Eriksson & Numberger-Thuy 2024

Clade Ankhurida clade nov. Diagnosis Zeugophiuroid ophiuroids with ambulacral halves firmly merged and with lateral arm plates showing a tentacle notch. Etymology From ‘ankh’, the ancient Egyptian hieroglyphic symbol for ‘life’, because the node in question represents the deepest known in the clade including the living ophiuroids. Taxa included Ophiolofsson gen. nov., Ophiopetagno Thuy, Eriksson & Numberger-Thuy, 2022 and all members of the clade Ophiovalida clade nov. (see below). Remarks We propose the new clade name Ankhurida clade nov. to designate a basalmost node in the evolutionary history of living ophiuroids. This node marks the earliest divergence within the clade encompassing all extant ophiuroids, and it is the sister group to an extinct clade consisting of the families Furcasteridae Stürtz, 1899, Eospondylidae Spencer & Wright, 1966, and Onychasteridae Miller, 1889. For the latter three families, in spite of the limited number of taxa represented in our phylogeny (Thuy et al. 2022), it is noteworthy that our tree topology favors a close relationship between the three, as previously suggested (Hotchkiss & Glass 2012).