Ototyphlonemertes parmula Diesing 1863, sp. nov.
Creators: name: Kajihara, Hiroshi
name: Tamura, Kotaro
name: Tomioka, Shinri
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Nemertea
Enopla
Monostilifera
Ototyphlonemertidae
Ototyphlonemertes

description: Ototyphlonemertes (parmula) nakaoae sp. nov.
(Figs 9, 10)
Material examined. Five specimens: ICHUM 5366 (holotype) (from Dam Trong); four paratypes, ICHUM 5367 (from Dam Trong), ICHUM 5368–5370 (from Dam Ngoai).
Description. Body length 4.1–6.2 mm (6.2 mm in holotype), width 0.2–0.3 mm (0.2 mm in holotype) (n =4). Epidermis whitish (Fig. 9A, D, E); cephalic furrow postcerebrally; tissues around brain slightly reddish (Figs 9B, E, F, 10A, B); cirri present in both anterior and posterior ends of body; cephalic cirrus formula (cf. Norenburg 1988b) observed in two specimens: A=2+2, B=0, C=9, D=6, E=4, tail= 14 in ICHUM 5368 (paratype); A=0, B=2, C=7+5, D=4+5, tail= 8 in ICHUM 5369 (paratype). Foregut–in-testine junction not markedly distinct. Statolith polygranular (Fig. 10 C–F), 8–11 µm (9 µm in holotype) in diameter (n =4), consisting of 7–8 (7 in holotype) granules; statocyst 19.2–26.1 µm (19.2 µm in holotype) in diameter (n =4). Proboscis diaphragm short (Figs 9F, 10A, B, G); gland-secretion ring situated posterior to hind end of basis; accessory-stylet pouches two, each containing 2–5 accessory stylets (3 in each in holotype) per pouch (n =4 individuals ×2 pouches), directing both forward and backward; central stylet (as well as accessory stylets) spiral (Fig. 10 H–K), 32–46 µm (32 µm in holotype) long; basis 39–52 µm (42 µm in holotype) long, 8–12 µm (8µm in holotype) wide (n =4), with each ridge twisting 1.5–2 (1.5 in holotype) times; basis length/width ratio 4.27–5.16 (5.16 in holotype); middle chamber bulbous; posterior chamber opaque, with specialized anterior part (Figs 9B, F, 10A, B). Intestinal diverticula deep. Posterior adhesive plate containing cells with orange contents (Fig. 9C). Gonads found in posterior 1/2 to 3/4 of intestinal region, alternating more or less regularly with intestinal lateral diverticula.
Distribution. So far recorded from the islands of Dam Trong (type locality) and Dam Ngoai, Vietnam.
Etymology. The specific name is a noun in the genitive case, after the Japanese ostracode biologist Dr Yuriko Nakao at Nihon University, Japan, who devotedly arranged our sampling trip to Phu Quoc.
Remarks. In the phylogenetic tree, Ototyphlonemertes (parmula) nakaoae sp. nov. was sister to O. (parmula) tsukagoshii sp. nov. (Fig. 2). Out of the seven species discovered in this study, O. (parmula) nakaoae turned out to be the only species that occurred at both the localities surveyed, the islands of Dam Trong and Dam Ngoai. Following O. (macintoshi) ani, it was the second most abundant species recovered in the present survey.
description: Published as part of 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, pp. 13-37 in Species Diversity 23 (1) on pages 24-27, DOI: 10.12782/specdiv.23.13, http://zenodo.org/record/4583901