Ophioplinthaca brachispina sp. nov., holotype (IDSSE-EEB-SW0106) A dorsal disc B ventral disc C center of the disc D–F disc spines G radial shield H оral frame I ventral side of the arm base J dorsal side of the arm base K dorsal arm L ventral arm M lateral arm. Abbreviations: ars arm spine, as adoral shield, ass adoral shield spine, dap dorsal arm plate, das dorsal arm spine, dp disc plate, gs genital slit, j jaw, lap lateral arm plate, m madreporite, os oral shield, rs radial shield, ts tentacle scale, vap ventral arm plate, vas ventral arm spine. Scale bars: 2 mm (A, B); 1 mm (C, G–M); 200 µm (D–F).