Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea) Author Thuy, Ben text European Journal of Taxonomy 2013 2013-07-02 48 1 242 journal article 22249 10.5852/ejt.2013.48 02866e62-ab61-4cf4-9d98-0248e251084e 2118-9773 3822836 E7080722-E348-448D-96E5-D537F4865BB5 Genus Ophiologimus H.L. Clark, 1911 Type species Ophiologimus hexactis H.L. Clark, 1911 , by original designation. Diagnosis LAPs with large, conspicuous tentacle notches; spine articulations not on elevated ridge and not sunken into depressions or notches; ventral portion of lateral arm plate strongly protruding ventroproximalwards; generally no spurs on outer proximal and inner distal edges of LAP. Remarks The LAPs of extant species of Ophiologimus are characterised by very large, generally deeply incised tentacle notches, the absence of a strong constriction or a strongly elevated distal portion, the moderately large, freestanding spine articulations and the relatively simple ridge on the inner side devoid of strongly widened parts. Closest similarities are shared with the LAPs of extinct Lapidaster gen. nov. , which differ mainly in the possession of at least one spur on the outer proximal and inner distal edges. As discussed above, it seems highly probable that Ophiologimus and Lapidaster gen. nov. come from a single lineage, in view of the striking similarities in LAP morphology displayed by both genera.