ИСТИНА

The Clarion-Clipperton Zone (CCZ) in the Northeast Pacific hosts the largest deposits of polymetallic nodules at abyssal depths. These nodules are rock formations that contain valuable metals and minerals and are intended to be mined. They also provide a diverse habitat for many deep-sea species. To date, little is known about the taxonomy, history and biogeography of deep-sea fauna, but this is essential for an accurate assessment of the risk of species extinction from large-scale mining. One of the most common megafauna taxa in the CCZ are brittle stars (Ophiuroidea), among which the genus Ophiotholia Lyman, 1880 shows increased abundance in the CCZ. In general, the genus Ophiotholia is distributed worldwide and currently comprises six species. The material collected on seven scientific expeditions in the CCZ was examined morphologically together with comparative material of all known species. Due to the small body size and the damage caused during sampling, morphological identification was often not possible, so the specimens were genetically analysed using a fragment of the mitochondrial COI gene. Scanning electron micrographs of the most important microstructural features were taken with selected specimens from the CCZ as well as the comparison material. One morphotype from the CCZ was identified as the described species Ophiotholia supplicans Lyman, 1880, while the second morphotype was recently described as Ophiotholia saskiae Eichsteller et al., 2023. The identification and description of such a poorly known genus improves the assessment of species diversity not only in the CCZ, but also in the entire deep sea.