Tajikacelis truncata, Curini-Galletti & Schockaert, 2021

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 : 522

Tajikacelis truncata n. sp.

( Figs 1F , 2F , 7 , 10F )

Diagnosis. Species of Tajikacelis with a recurved stylet, 49 μm long in the holotype, with a straight proximal opening of 19 μm, narrowing to 10 μm and 5 μm wide at the distal opening, which is square-ended. Pharynx at about midbody. With elongate seminal vesicles. Ovaries at the base of the pharynx and about 30 densely packed testes between brain and ovaries. Female duct widened to a prepenial bursa with a vagina.

Occurrence. Gulf of Panama, Isla Bartolomè (Las Perlas Is., Panama) (8°40’22.87”N; 79° 3’12.58”W), about 1 m deep, coarse sand (type locality) (December 2011 by M.C-G). Iguana Island ( Panama)(7°37’45.35”N; 79°59’50.76”W), at a depth of 1.5–2 m, medium sand (February 2016 by M.C-G) .

Material studied. Four whole mounts (one of which designated as holotype) and two serially sectioned animals from the type locality (holotype: FNMH http://id.luomus.fi/KV.668; paratypes CZM831-835 ); three whole mounts and one sectioned animal from Iguana Island ( CZM836-839 ) .

Etymology. The species name refers to the truncated tip of the stylet.

Additional remarks. The dark round structures as seen in T. acuta n.sp are also present in this species ( Fig. 7 A ). The species is cited as Archimonocelididae gen. n. 2 sp. n. 2 in Scarpa et al. (2017).

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 7. Tajikacelis truncata n. sp. (A) Head in the living animal showing the dark pigmented spots. (B) The copulatory organ in the living animal. (C) Posterior part of the living animal, showing most of the genital organs. (D1–D2) Micrograph and drawing of the copulatory stylet in the holotype (scale bar = 20 µm).

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