New species of Temnocephala Blanchard (Platyhelminthes, Temnocephalida) ectosymbiont on Aegla serrana Buckup & Rossi (Crustacea, Anomura) from southern Brazil

A new species of the genus Temnocephala Blanchard, 1849 is described from southern Brazil, ectosymbiont on Aegla serrana Buckup & Rossi, 1977, an anomuran crustacean, collected in a creek and a reservoir of the highlands in the State of Rio Grande do Sul. All crustaceans examined were positive for this species of Temnocephala and carried eggs in different regions of the ventral side: perioral area, pleural strips, esternal plates, pereiopods and chelipods; to a lesser extent in the dorsal side of the cephalothorax and dorsal side of the uropods; as well as adult and young specimens. The most distinctive characters of the new species are: 1) cyanophilous glands forming an irregular-shaped, grape-like, bunch of approximately 10-15 cells, deeply staining with hematoxylin; 2) shape and size of the cirrus and its introvert section; 3) number, size and distribution of the rhabdite glands and 4) shape and position of the post tentacular, 'excretory' syncytial plates, with the off-centered nephridiopore