Ophiomyces undetermined

• Main Authors: O'Hara, Timothy D., Thuy, Ben
• Format: Other/Unknown Material
• Language: unknown
• Published: 2022
• Subjects: Biodiversity; Taxonomy; Animalia; Echinodermata; Ophiuroidea; Ophioscolecida; Ophiohelidae; Ophiomyces; Ophiomyces undetermined; Pacific; Paterson; Port Essington; Tristan; North Atlantic
• Online Access: https://zenodo.org/record/6411772; https://doi.org/10.5281/zenodo.6411772

Ophiomyces sp. juvenile Fig. 4E Material examined. MD 50 DC91, MNHN IE.2009.1577 (25). MD 50 DC137, MNHN IE.2009.1578 (1). Comparative Material. Ophiomyces grandis Lyman, 1879: BSS/638 DP, Eastern Bass Strait, slope, 102 km SE of Cape Conran, Victoria, 38° 29.5´S, 149° 32.4´E, 1630 m, 16/11/1981, MV F52776 (1). IN2018_ V06 / 007, Deep west of Pedra, 44° 20.844´S, 146° 56.82´E to 44° 22.596´S, 146° 56.76´E, 1745 m, 24/11/2018, MV F272372 (5). IN2018_ V06 / 074, East Maatsuyker flat, 44° 12.858´S, 146° 16.02´E to 44° 13.02´S, 146° 15.48´E, 1501 m, 3/12/2018, MV F271968 (7). Remarks. The MD50 material is small with the largest specimen only 4 mm dd (Fig. 4E). All are badly damaged. The species of Ophiomyces are often distinguished by the number and position of tentacle scales and oral papillae (Litvinova 2001; O’Hara 1990; Paterson 1985), which however, can be variable depending on the age and condition of the specimens. The MD 50 specimens have only the distal oral papillae widened at the tip into the classic “hockey stick” shape, which is characteristic of O. grandis Lyman, 1879. However, the configuration of tentacle scales (one to two on the VAP and two on the LAP of basal segments reducing to one large LAP scale by the eighth segment) and the radial row of sparse disc spines, is characteristic of the Indo-Pacific species O. delata Koehler, 1904. The type locality of Ophiomyces grandis Lyman, 1879 is off Tristan da Cunha at 1828 m. The other records from the southern hemisphere (see material examined) are from depths of 1000–1840 m. North Atlantic records on the other hand are much shallower (124–802 m, e.g., Ordines et al. 2019) and may represent a distinct species. Two of the other genera in the Ophiohelidae, Ophiotholia and Ophiohelus, have diagnostic umbrella-shaped spines on the arms. The only other recorded genus in the family is Ophiothauma H.L. Clark, 1938, known from only one specimen of O. heptactis H.L. Clark, 1938 from off Port Essington, Coburg Peninsula, Northern Australia. Re-examination of the ...