Ophiopetagno was named by Thuy et al. (2022) [Holotype: Natural History Museum Luxembourg (MnhnL) OPH087, a lateral arm plate. Description: Lateral arm plates (Fig. 1; Supplementary Fig. 3) small, elongate, with dorsal edge slightly concave due to weak constriction. Ventral plate portion protruding and distally incised by tentacle notch. Outer surface stereom finely meshed with trabecular intersections transformed into small tubercles; vertical band of more fine-meshed stereom along distal edge of plates, devoid of spurs but with poorly defined furrow parallel to proximal plate edge. Up to three lateral arm spine articulations in vertical row, each consisting of single opening surrounded by elevated ridge. Inner side of lateral arm plates with large, sub-triangular vertebral articulation; ventral edge of lateral arm plates slightly convex and lined with up to five bulges each showing small perforation on inner side, corresponding to groove spine articulations. Vertebrae (Fig. 1; Supplementary Fig 3) composed of fused ambulacrals, roughly cylindrical, with slightly concave waist; lateral sides with deep podial basin distally, and sub-triangular articulation surface proximally, matching vertebral articulation on inner side of lateral arm plates. Distal side with large, dorsally converging zygocondyles; water vessel canal running entirely within vertebra, distally enclosed by large zygosphene.]. It is not extant. Its type is Ophiopetagno paicei.

It was assigned to Ophiuroidea by Thuy et al. (2022).