Ophiomusa sp.

Nethupul, Hasitha, Stöhr, Sabine & Zhang, Haibin, 2022, New species, redescriptions and new records of deep-sea brittle stars (Echinodermata: Ophiuroidea) from the South China Sea, an integrated morphological and molecular approach, European Journal of Taxonomy 810 (1), pp. 1-95 : 28-29

Ophiomusa sp.

Fig. 13H–L

Material examined

CHINA • 1 spec.; South China Sea , near Xisha Islands; 16°39.75′ N, 112°7.43′ E; depth 663 m; 15 Mar. 2020; collection event: stn SC006; MSV Shenhaiyongshi leg.; preserved in -80°C; GenBank: MZ 198764 ; IDSSE EEB-SW0010 .

Remarks

We collected a damaged specimen that could only be identified to genus level as Ophiomusa . It differs from O. lymani by the coverage of irregular scales on the disc center, the radial shields being smaller and more triangular, large ventral disc scales connected to the oral shield entirely covering the interradial space between the genital plates and having an ventral arm plate present on up to seven arm segments from the arm base ( Fig. 13H–L ). Ophiomusa sp. forms a sister clade to O. lymani on our molecular tree (see below). In the phylogeny by Christodoulou et al. (2019), this sister clade is composed of O. faceta ( Koehler, 1922a) and O. facunda ( Koehler, 1922a) , which suggests that our specimen may also belong to one of these species. Ophiomusa faceta is similar to Ophiomusa sp. by having irregular disc scales on the disc center and radial shields separated by a single layer of disc scales, but differs by lacking a ventral arm plate beyond the second arm segment, smooth dorsal disc surface and 6–7 arm spines on the lateral arm plate. Ophiomusa facunda is similar to Ophiomusa sp. by having a rough dorsal disc surface and radial shields separated by a single layer of disc scales, but differs in having large dorsal disc scales, the entire ventral surface occupied by a large interradial scale, in lacking a ventral arm plate beyond the third arm segment and having 6–7 arm spines on the lateral arm plate. The differences between those species and our specimen prevent us from associating it with either of them.

Figures

Fig. 13. A–G. Ophiomusa lymani (Wyville Thomson, 1873) (IDSSE EEB-SW0008). A. Dorsal disc. B. Ventral disc. C. Oral frame. D. Ventral arm base. E. Dorsal arm base. F. Ventral arm. G. Lateral arm plate with arm spines. H–L. Ophiomusa sp. (IDSSE EEB-SW0010). H. Dorsal disc. I–J. Ventral disc. K. Dorsal arm. L. Ventral arm. Abbreviations: as = adoral shield; ars = arm spine; dap = dorsal arm plate; gs = genital slit; lap =lateral arm plate; os = oral shield; rs = radial shield; tp = tentacle pore; vap = ventral arm plate. Scale bars: A = 10 mm; B = 15 mm; C–E = 2 mm; F, H–L = 1 mm; G = 500 µm.