Tajikacelis tajikai, 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 : 517-519

Tajikacelis tajikai n. sp.

( Figs 1A , 2A , 3 , 10A )

Diagnosis. Species of Tajikacelis with a curved stylet, 58–63 μm long (N=5), with a proximal opening of 30–34 μm, narrowing to 8–10 μm at around 1/3 of its length and 3–4 μm wide close to its end and widening again to around 5 μm. With a truncated distal opening. Testes in a single row, 12–13 in front of the ovaries and about 30 from ovaries to the pharynx. Postpenial widened female duct with a dorsal vagina.

Occurrence. South George Beach , Point Lookout, Stradbroke Island, Queensland Australia (27°26’10.8”S; 153°32’36.2”E), lower intertidal in a slightly protected area of the beach, with medium sand (type locality)(13 August 1996 by M.C-G.) .

Material studied. Several animals studied alive, five whole mounts, one of which holotype ( QM G23851); the other four and 11 sectioned individuals are paratypes ( CZM809-823 ) .

Etymology. the species name honors Dr. K-I. Tajika.

Additional remarks. With a thin band of brown pigment running from the tip of the snout to the statocyst. The common female duct, widened into a bursa, is surrounded by a weak muscle layer and lined with a rather high epithelium that becomes lower towards the pore. Between the pore and the level of the copulatory organ, a dorsal vagina is present. The vaginal duct is short and broad, lined with a low epithelium. Just in front of the copulatory organ a cluster of glands opens at the ventral surface. The female cement glands around the female pore are exceptionally large. A short genito-intestinal duct behind the female pore leads directly to the intestine, whose posterior end shows resorbing features.

Karyology. n=7. With five pairs of chromosomes slightly differing in size: three pairs of which are metacentric, and two pairs acrocentric; and with two much smaller chromosome pairs, one of which metacentric, the other acrocentric ( Fig 3E–F ).

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 3. Tajikacelis tajikai n. sp. (A) Sagittal reconstruction of the posterior part of the animal, seen from the left (scale is approximative). (B1–B2) Micrograph and drawing of the copulatory stylet in the holotype. (C1, C2, D1, D2) Micrographs and drawings of the copulatory stylet in two paratypes. (E, F) Two chromosome sets 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).