First record of Epistylis plicatilis (Ciliophora: Peritrichia) attached to Pomacea canaliculata (Mollusca: Gastropoda) in Southern Brazil

Abstract

A more complete morphological characterization of Epistylis plicatilis Ehrenberg, 1831, a colonial peritrich epibiotic on the gastropod Pomacea canaliculata (Lamarck) in two freshwater environments in Southern Brazil was provided in the present study. The colonial sessile E. plicatilis possessed elongate zooids that range in size in vivo from 105.0 to187.5 μ m in length and from 25.0 to 52.5 μ m in width. The cell had a single contractile vacuole located near the peristome. A “C-shaped” macronucleus lay in the middle of the cell. Colonies of E. plicatilis had up to 100 zooids, but the majority possessed 10–20 zooids that were similar in size. The oral ciliature revealed by the protargol staining technique consisted of an outer haplokinety and an inner polykinety that performs approximately 1 ½ turns around the perimeter of the peristome before entering the infundibulum. Three infundibular polykineties each consisting of three rows of kinetosomes were identified. This is the first record of E. plicatilis in Brazil.