Rhabdostyla annulata (Stokes 1886) nov. comb

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— Fig. 1, D

Opisthostyla annulata Stokes, 1886 (b): 565, fig. 12, 13.

[ Rhabdostyla] (Opisthostyla) annulata Stokes,1886 — Kahl, 1935: 679, pl. 129. Fig. 20

Epistylis (Rhabdostyla) annulata Stokes, 1886 — Stiller, 1971: 70, pl. 36, fig. 6

Diagnosis: Size about 22–35 µm. Conical body, less than twice long as wide. Slightly changeable in shape, somewhat bumpy or with almost straight side margins. Zooid located obliquely or vertically over the peduncle, which has the same size as the body and a slight curve in the distal portion. Pellicle strongly transversely striated. Revoluted peristomial collar, with ciliary circles. Infundibulum reaches a third of the body’s length. Contractile vacuole found on the right margin of the infundibulum in the upper quarter of the body. Macronucleus, thin and horseshoe-shaped, located in the middle of the body, positioned horizontally. Found in freshwater lakes living on algae.

Remarks: diagnosis compiled from Stokes (1886), Kahl (1935) and Stiller (1971).