Trichoptera — the newest insect order host of temnocephalans (Platyhelminthes, Temnocephalida) and the description of a new species of Temnocephala from Brazil

Abstract

Trichoptera Kirby, 1813, is the second order of Insecta Linnaeus, 1758 (after Hemiptera Linnaeus, 1758) to be found hosting temnocephalans anywhere in the world. Temnocephalans were found on caddisfly larvae from the genus Barypenthus Burmeister, 1839 while collecting aquatic insects from a small creek in Serra do Cipó, State of Minas Gerais, Brazil. Thirty-six larvae and their cases were examined, of which 20 (55.5%) were positive for specimens of Temnocephala Blanchard, 1849. Juvenile and adult temnocephalans were always devoid of body pigmentation and were living on the dorsal and ventral body surfaces of the larvae. The eye pigmentation was deep red, disappearing in specimens fixed in ethanol. Eggs were found in larger numbers on the dorsal thoracic segments. The most distinctive characters of the temnocephalans found on caddisfly larvae were found in the cirrus and the vagina. The comparison of the general anatomy and, in particular, the morphology of the cirrus and the vagina with those of Temnocephala curvicirri Amato & Amato, 2005, described from aquatic heteropterans (Belostoma spp.), from the State of Rio Grande do Sul, which is revisited, showed that although these characters are of the same type and nature they are not equal, differing primarily in size and morphology of the cirrus and the muscularity of the middle portion of the vagina. The egg deposition sites are different and the cirrus and the vagina are characterized for the first time as being ‘complex’.