Baseodiscus zebra, 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 : 529-530

BASEODISCUS ZEBRA SP. NOV.

( FIG. 2P )

Baseodiscus mexicanus: Colin & Arneson, 1995: 150– 151 , fig. 686 ( Palau); Chernyshev & Volvenko, 2008: 106 (Komodo, Indonesia); Kajihara, Yoshida & Uyeno, 2012: 754–755, fig. 2A, B (Okinawa, Japan); Kajihara, 2017: 423, fig. 16.2d.

Zoobank registration: u r n: l s i d: z o o b a n k. org:act: EAA8D387-3EC0-4F9B-AE38-2DED799D7DFB.

Material examined: Holotype, RUMF-ZN-00001 (DNA voucher ICHUM 6317 ), 31 March 2012, 3–4 m depth, Cape Manza (26°30′16″N, 127°50′39″E), On’na-son, west coast of Okinawa-jima, Japan, SCUBA, collected by D. Uyeno.

Sequences: From ICHUM 6317 : LC178607 , 18S (1795 bp) ; LC178639 , 28S (2086 bp) ; LC178688 , 16S (505 bp) ; LC190960 , COI (658 bp) .

Etymology: The new specific name is a noun in the nominative case, referring to the colour pattern of the species.

Description: Head white, with indigo dorsal and ventral cephalic patches; with transverse cephalic furrow encircling neck; numerous secondary furrows present; numerous, small, black eyes distributed laterally along sides of head. Body white, with numerous bands of same colour as cephalic patches ( Fig. 2P ).

Distribution: Although molecularly confirmed only from the type locality, Okinawa ( Japan), B. zebra is probably distributed widely in the western Pacific.

Remarks: Sequences LC190960 ( COI) and LC178688 (16S) from the holotype differ by 12.6% and 6.8% in uncorrected p -distance from KF935503 ( COI) and KF935449 (16S), respectively, both from MCZ IZ- 135321 collected in Baja California, Mexico and identified as B. mexicanus by G. Giribet ( Kvist et al., 2014; MCZbase, www.mcz.harvard.edu). Kajihara et al. (2012) argued a possible amphi-Pacific distribution for B. mexicanus , but the western-Pacific population (possibly extending from Japan via Palau to Australia; Colin & Arneson, 1995; Chernyshev & Volvenko, 2008) is here regarded as a distinct species.

Because the type locality of B. mexicanus is Mazatlán, Mexico ( Bürger, 1893), the name mexicanus should be applied to the eastern-Pacific population, in which Coe (1940: 261) noted the colour to be variably brownish green, maroon, deep red, mahogany or brownish violet. The body colour appears to be generally reddish in B. mexicanus , whereas in B. zebra it is bluish.

Figures

Figure 2. A, Eopilidion misakiense gen. et sp. nov., holotype, ICHUM 6303, lateral view, head to the right; B, Oxypolella hiebertae sp. nov., holotype, MIMB 42256; C, Cephalomastax brevis Iwata, 1957, ICHUM 6304; D, E, Valencinura jambio sp. nov., holotype, ICHUM 6305, anterior body fragment (D) and enlargement of intestinal region (E) showing yellowish proboscis (indicated by arrowheads); F, Baseodiscus takakurai Gibson, 1995, ICHUM 6306; G, Baseodiscus profundus sp. nov., holotype, MIMB 42257; H, I, Baseodiscus narusei sp. nov., holotype, ICHUM 6310, anterior end of body, dorsal (H) and ventral (I) views; J, Baseodiscus paracelensis sp. nov., holotype, MIMB 33132; K, Baseodiscus komatsui sp. nov., holotype, NMNS-Ne 1; L, Baseodiscus unicolor Stiasny-Wijnhoff, 1925; M, Baseodiscus giribeti sp. nov., holotype, MCZ IZ-135324; N, Baseodiscus cf. amboinensis (Staub, 1900); O, Baseodiscus hemprichii (Ehrenberg, 1828-1831), specimen from Okinawa, different from any voucher specimens in this study; P, Baseodiscus zebra sp. nov., holotype, RUMF-ZN-00001; Q, Baseodiscus quinquelineatus (Quoy & Gaimard, 1833), ICHUM 6319. Photographs by H. Kajihara (A, C, D, E, F, O), A.V. Chernyshev (B, G, J), T. Naruse (H, I), H. Komatsu (K), G. Giribet (L, M), D. Uyeno (P), and R.Yoshida (Q).