Baseodiscus ohtsukai, Kajihara & Abukawa & Chernyshev, 2022

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 : 533-534

BASEODISCUS OHTSUKAI SP. NOV.

( FIG. 7D, E )

Zoobank registration: u r n: l s i d: z o o b a n k. org:act: 5DBE9E10-9A24-447B-9A7F-EE5DD10891E0.

Material examined: Holotype, ICHUM 6327 , 29 May 2001 off Toi Cape (31°19′12″N, 131°21′00″E), Kagoshima, Japan, 118 m depth, station 12 of the R / V Toyoshio-maru Cruise 01-06, collected by H. Kajihara.

Sequences: From the holotype: LC178592 , 18S (1799 bp) ; LC178622 , 28S (2117 bp) ; LC178667 , 16S (456 bp) ; LC190945 , COI (629 bp) .

Etymology: The new specific name is a noun in the genitive case, from Prof. Susumu Ohtsuka, a Japanese crustacean biologist, leader of marine biodiversity studies with the R/V Toyoshio-maru of Hiroshima University.

Description: Body broad, dorsoventrally flattened, 15 cm long, 4 mm wide; ground colour white, dorsally with wide purplish brown stripe, ventrally with minute flecks of same colour (lacking in front of cephalic furrow); transverse cephalic furrow present, encircling neck; secondary furrows present; small, black ocelli distributed along dorso-lateral surfaces of head; proboscis pore sub-terminal; mouth small ( Fig. 7D, E ). Found in mucus tube formed with mud and sand particles.

Distribution: So far known only from the type locality, sublittoral, off southern Kyushu in the Pacific (present study).

Remarks: Baseodiscus ohtsukai looks similar to B. urgorrii in that it has a whitish background colour and a broad, mid-dorsal longitudinal stripe, but differs from the latter in the colour of the stripe, which is more reddish than that in B. urgorrii .

Figures

Figure 7. A, Baseodiscus narusei sp. nov., holotype, ICHUM 6310, entire body, showing characteristic lateral edges; B, Baseodiscus paracelensis sp. nov., holotype, MIMB 33132, entire body; C, Baseodiscus aff.marmoratus (Bürger, 1890), anterior end of body, ventral view, head to the left; D, E, Baseodiscus ohtsukai sp. nov., holotype, ICHUM, 6327, drawings of anterior end of body viewed dorsally (D) and ventrally (E); F, G, Baseodiscus urgorrii sp. nov., holotype, MCZ IZ-135319, anterior end of body viewed dorsally (F) and ventrolaterally (G). Photos by T. Naruse (A), A. V. Chernyshev (B, C), and G. Giribet (F, G).