Tajikacelis itoi (Tajika, 1981)

Curini-Galletti, Marco & Schockaert, Ernest R., 2021, Six new species ofArchimonocelididae Meixner, 1938 (Platyhelminthes, Proseriata) from the Pacific, with proposal of a new genus, Zootaxa 4965 (3), pp. 515-528 : 523-524

Tajikacelis itoi (Tajika, 1981)

( Figs 1G , 2G , 8A–C , 10G )

Diagnosis. Species of Tajikacelis with a very strongly recurved stylet, 88–99 μm long (N=6), with a proximal opening of 38–46 μm quickly narrowing to about 11–15 μm and 5–7 μm distally and with an oblique terminal opening. Ovaries close to the pharynx. More than 40 densely packed testes from midway brain and ovaries, extending just behind the ovaries. Female duct widened to a postpenial bursa with a two ventral vaginas.

Occurrence. West Hokkaido, Japan.

Material studied. The type material, consisting of 19 series of sections (one of which the holotype) and 7 whole mounts.

Additional remarks. T. itoi is the only species of the genus differing for the orientation of its stylet, with its convex side pointing backwards instead of forwards. As a consequence, its distal opening is anteriorly oriented; whereas it is ventrally and backwards oriented in the rest of species. The unique feature of the species could be confirmed on direct examination of the type material, as well as the accuracy of Tajika’s description (1981).

Figures

FIGURE 1. General appearance of the species of Tajikacelis. (A) T. tajikai n. sp. (B) T. macrostomoides n. sp. (C) T. nematoplanoides n. sp. (D) T. artoisi n. sp. (E) T. acuta n. sp. (F) T. truncata n. sp. (G) T. itoi (after Tajika 1981).

FIGURE 2. Genital organs of (A) T. tajikai n. sp. (B) T. macrostomoides n. sp. (C) T. nematoplanoides n. sp. (D) T. artoisi n. sp. (E) T. acuta n. sp. (F) T. truncata n. sp. (G) T. itoi (after Tajika 1981).

FIGURE 8. Tajikacelis itoi (A–C) The copulatory stylet in three syntypes. T. keke (D) Copulatory stylet after Martens & Curini- Galletti, 1989. (scale bar = 20 µm).

FIGURE 10. The copulatory stylets in the holotypes of the species of Tajikacelis n. gen. (scale bar = 20 µm).