Laetmogone cf. wyvillethomsoni Théel, 1879

Laetmogone cf. wyvillethomsoni Théel, 1879 View in CoL

Figs 5 View Figure 5 , 6 View Figure 6

Laetmogone cf. wyvillethomsoni, Bribiesca-Contreras et al., 2022: 78–79, fig. 49. View in CoL View Cited Treatment

Material examined.

West Pacific • 1 specimen; South China Sea ; 18°38.20'N, 114°21.29'E; depth 3568 m; 13 July 2019; preserved in - 80 ° C; IDSSE - EEB-HS 48 GoogleMaps . • 1 specimen; South China Sea ; 18°38.22'N, 114°21.36'E; depth 3566 m; 13 July 2019; preserved in - 80 ° C; IDSSE - EEB-HS 49 GoogleMaps .

Description.

Body cylinder-shaped and slender. 15.6–24 cm long and 5.2–7 cm wide before preservation (Fig. 6 A – E View Figure 6 ), with the length exceeding the width by more than three times. Mouth anterior, subventral (Fig. 6 A – D View Figure 6 ). Anus terminal, slightly dorsal. Colour dark violet in both vivo and fixed states. Tentacles 15, of similar size. Odd ambulacrum naked. Conical tube feet 21–28, arranged in single rows on ventrolateral radii. Each dorsal radius with a single row of 12–17 long papillae. Ossicle morphology unavailable due to poor condition of the South China Sea specimens.

Remarks.

The South China Sea specimens in this study (Fig. 6 View Figure 6 ) belong to the same species (see Table 2 View Table 2 below, 0–0.8 % K 2 P genetic distance) of the Clarion-Clipperton Zone (CCZ) specimen described by Bribiesca-Contreras et al. (2022) and our phylogenetic analyses showed a well-supported clade (see Fig. 7 View Figure 7 below, BS = 90, PP = 0.94). The CCZ specimen resembled L. wyvillethomsoni closely, as reported by Théel (1879) in the original publication, but no rod-shaped ossicles were found in the dorsal skin. The South China Sea specimens were in poor condition and mostly fragmented, which made it impossible to obtain ossicles from specific tissue sites. Therefore, we only provided molecular data and images and morphological studies of more specimens are needed to determine the specific taxonomic status of this species. The discovery of specimens collected from the South China Sea expanded their geographical distribution from the eastern to the western Pacific Ocean, with a maximum recorded depth of 3568 m.