Tachyblaston reversum ( Collin, 1909 ) Chatterjee & Dovgal & Sautya, 2023

Chatterjee, Tapas, Dovgal, Igor & Sautya, Sabyasachi, 2023, New find of Dactylophrya-stage of parasitic suctorian of genus Tachyblaston Martin, 1909 (Ciliophora, Suctorea) with comments on genus taxonomy, Zootaxa 5389 (2), pp. 266-274 : 273

Tachyblaston reversum ( Collin, 1909) n. comb.

= Ophryodendron reversum Collin, 1909 , syn. n.

= Pleurophryodendron reversum ( Collin, 1909) , syn. n.

Diagnosis (based on Collin 1909, 1912, and own data): Marine suctorian ciliate, the Dactylophrya -stage of which has unflattened pyramidal or pear-shaped cell body, covered by extremely thin, transparent lorica, aperture of which have noticeable lateral clefts ( Fig. 2A–D ; Fig. 3A, B ; Fig. 5C ). There are spherical of oval macronucleus, micronuclei not observed. Up to 8 unciliary larval stages (dactylozoites) form at apical surface of the body. Dactylozoites ( Fig. 3A, B ; Fig. 5C ) are spindle-like, with sharp anterior and rounded dorsal ends. The anterior end with feeble marked knob. Macronucleus of dactylozoit, rounded, centrally located. There are from 1 to 2 large contractile vacuole, positioned above macronucleus. Reproduction is by semi-internal successive vermigemmy. The trophont stage unknown.

Measurements (in µm, based on one individual in present find): Lorica length 265; lorica width 122; stalk length 101; stalk width 17.

Measurements of dactylozoites (in µm, based on three individuals in present find): cell-body length 103– 119, width 27–36; dimensions of macronucleus 15–18×10–13; contractile vacuole dimensions 20–23×26–30.

Localization: Abdomen segments and furca of a harpacticoid host.

Type locality: Sète , France .

Type host: Ameira sp.

The host of trophont stage unknown.

Figures

FIGURE 2. A—localization of Tachyblaston reversum on the host body; B—stalk of T. revetsum: C, D—magnified view on T. revetsum (c—lorica aperture cleft).

FIGURE 3. A, B—squashed individual with good visible dactylozoites.

FIGURE 5. Dactylophrya-stage of Tachyblaston found by different authors (A—after Collin 1912; B—after Gassovsky 1916; C—after Collin 1912 as Ophryodendron reversum).