No abstract

Austrolimnius cleidecostae sp. nov. is one of the smallest species of Elmidae from the Neotropical region. The new species is described and illustrated based on male and female specimens. This species represents the first record in Elmidae of mandibles with an articulated, sclerotized process on inner subapical edge. The specimens were collected from streams in the Atlantic rainforest of São Paulo and Santa Catarina, and habitat notes are given. An updated key for the Austrolimnius Carter & Zeck, 1929 of Brazil is provided. Austrolimnis browni Hinton, 1971 and A. musgravei Hinton, 1939 are recorded for the first time from Brazil.

The genus Hexacylloepus extends from the Neotropical region to the southwestern United States of America. At present, 25 species are known from 20 countries, with no new species proposed since 1972. In this paper, we describe and illustrate 18 new species (H. barrae; H. calori; H. casariae; H. froehlichi; H. geiseri; H. grandis; H. iassu; H. keitai; H. maierae; H. manauara; H. metapa; H. phalluspilosus; H. shorti; H. taylorae; H. thoracica; H. tibialis; H. ubirajarai; H. zaninii), from eight countries and give the first records of the genus from Suriname and Guyana.