Ototyphlonemertes (duplex) chernyshevi 1863

Kajihara, Hiroshi, Tamura, Kotaro & Tomioka, Shinri, 2018, Histology-free Descriptions for Seven Species of Interstitial Ribbon Worms in the Genus Ototyphlonemertes (Nemertea: Monostilifera) from Vietnam, Species Diversity 23 (1), pp. 13-37 : 18-20

Ototyphlonemertes (duplex) chernyshevi sp. nov.

( Fig. 4 )

? Ototyphlonemertes (O.) cf. martynovi: Chernyshev 2007: 199, fig. 1f, g.

Material examined. Three specimens, all from Dam Trong; ICHUM 5348 (holotype); ICHUM 5349 , 5350 (two paratypes) .

Description. Body length 8–12 mm (8 mm in holotype), width 0.2–0.3 mm (0.2 mm in holotype) (n =3) ( Fig. 4A, B ). Epidermis whitish ( Fig. 4A ); cephalic furrow postcerebrally; tissues around brain reddish; cirri present on cephalic region and hind end of body. Statoliths two-partite ( Fig. 4 C–E), 10.2–11.7 µm in diameter (10.2 µm in holotype) (n =3); statocyst 24.8–29.5 µm in diameter (24.8 µm in holotype) (n =3). Proboscis diaphragm short ( Fig. 4F ); gland secretion ring situated anterior to hind end of basis; accessory stylet pouches two ( Fig. 4F ), each containing two accessory stylets (directing either anteriorly or posteriorly), situated laterally to central-stylet basis; central stylet smooth ( Fig. 4 F–H), 28.2–33.6 µm long (33.6 µm in holotype); basis 26.2–30.8 µm long (30.8 µm in holotype), 9.4–11.8 µm wide (11.8 µm in holotype) (n =3); basis length/width ratio 2.28– 2.80 (2.61 in holotype) (n =3); posterior chamber opaque, without specialized anterior portion. Intestinal diverticula shallow and sack-like. Posterior adhesive plate with cells containing orange contents ( Fig. 4I ).

Distribution. So far known only from the type locality, the island of Dam Trong, Vietnam.

Etymology. The specific name is a noun in the genitive case, after the distinguished nemertean biologist Professor Dr Alexei Viktorovich Chernyshev at A. V. Zhirmunsky Institute of Marine Biology, Far East Branch of Russian Academy of Science, and concurrently at Far Eastern Federal University, in recognition of his significant contribution to the nemertean systematics in general and, in particular, that of Ototyphlonemertes , as well as to clarification of Vietnamese nemertean fauna.

Remarks. Ototyphlonemertes ( duplex ) chernyshevi sp. nov. is similar to a specimen from Van Phong Bay, Vietnam (12°39′N, 109°20′E), which was uncertainly identified as O. ( duplex ) martynovi by Chernyshev (2007), in that their stylet bases are thick and stumpy, by which they can be distinguished from O. ( duplex ) envalli sp. nov. and O. ( duplex ) norenburgi sp. nov.; the basis is thinner in the latter two in comparison with that of O. ( duplex ) chernyshevi . Our unpublished sequence data indicate that O. ( duplex ) chernyshevi is genetically different from O. ( duplex ) martynovi s.str. (14.89–16.29% in uncorrected p -distance; 0.1869 – 0.2109 in K2P).

Figures

Fig. 4. Ototyphlonemertes (duplex) chernyshevi sp. nov. A, Entire body; B, composite photomicrograph of squeezed specimen; C–E, statoliths; F, stylet apparatus, G, H, central stylets and bases; I, posterior end of body. A, C, F, I, ICHUM 5348 (holotype); B, G, ICHUM 5349 (paratype); E, H, ICHUM 5350 (paratype).