Baseodiscus nipponensis, (HUBRECHT, 1887)

Kajihara, Hiroshi, Abukawa, Shushi & Chernyshev, Alexei V., 2022, Exploring the basal topology of the heteronemertean tree of life: establishment of a new family, along with turbotaxonomy of Valenciniidae (Nemertea: Pilidiophora: Heteronemertea), Zoological Journal of the Linnean Society 196, pp. 503-548 : 538

BASEODISCUS NIPPONENSIS ( HUBRECHT, 1887)

( FIG. 3N )

Eupolia nipponensis Hubrecht, 1887: 14–15 , pl. I, figs4, 5, 10, pl. VII, figs 6, 11, 12 (Sagami Bay, Japan).

Baseodiscus nipponensis: Bürger, 1904: 84 .

Baseodiscus nipponicus (lapsus calami): Kajihara, 2017: 423 (Sagami Bay, Japan).

Material examined: ICHUM 6338 , extracted DNA and remaining body preserved in 99% EtOH; 19 February 2014, dredged from Sagami Bay (between 35°05′57″N, 139°34′52″E, 249 m depth and 35°05′47″N, 139°34′05″E, 309 m depth), Japan, station 2 of the 2 nd JAMBIO Coastal Organism Joint Survey ( Nakano et al., 2015), collected by H. Kajihara.

Sequences: From ICHUM 6338 : LC178630 , 28S (1121 bp); LC178677 , 16S (505 bp) .

Description: Body length 3.5 cm, width 1 mm; dorsally reddish brown, ventrally white; eyes present; cephalic furrow encircling head; secondary furrows present ( Fig. 3N ).

Distribution: So far known only from Sagami Bay, Japan ( Hubrecht, 1887; Kajihara, 2017; present study).

Remarks: Hubrecht’s (1887) material of Eupolia nipponensis was dredged from green mud at a depth of 345 fathoms (about 640 m) on 12 May 1875 by HMS Challenger in Sagami Bay (35°11′00″N, 139°28′00″E). Three body fragments were illustrated by Hubrecht (1887: pl. I, figs 4, 5, 10). Although nothing is mentioned about the size and coloration of these specimens, they were probably small (probably a few centimetres) and devoid of colour pattern, although Hubrecht (1887: fig. 5) may have illustrated the dorsal pigmentation that is also seen in our specimen (ICHUM 6338) from a depth of 309 m in Sagami Bay. Judging from the body size, our specimen (3.5 cm long) was probably a juvenile.

Figures

Figure 3. A, Baseodiscus aff. marmoratus (Bürger, 1890) (voucher DNA, ICHUM 6322); B, Baseodiscus aff. maculosus (Bürger, 1895a) (voucher DNA, ICHUM 6324); C–E, Baseodiscus delineatus (Delle Chiaje, 1822-1829), ICHUM 6326; F, Baseodiscus cf. curtus (Hubrecht, 1879), ICHUM 6328; G, H, Baseodiscus urgorrii sp. nov., holotype, MCZ IZ-135319, entire body (G) and protruding proboscis (indicated by an arrowhead, H); I, Baseodiscus punnetti (Coe, 1904), specimen different from any voucher specimens in this study; J, K, Baseodiscus kakuii sp. nov., holotype, ICHUM 6334, anterior body (J) and