Two new species of Hyalella (Amphipoda, Dogielinotidae) from Brazil

Abstract

Two new freshwater species of amphipods from Brazil are described here. Hyalella xakriaba n. sp. occurs in the hydrographic basin of the São Francisco River, in a biome characterized by a semiarid climate, in the state of Minas Gerais. This new species constitutes the northernmost record of the genus in Brazil. Hyalella kaingang n. sp. occurs in the hydrographic basin of the Mampituba River, located in Rio Grande do Sul, the southernmost state in Brazil. Currently 14 species of Hyalella are known in Brazil, cave species among them. Some morphological characters and their respective states are analyzed, and constitute an important new tool for species identifications. In particular, we describe the cuticular structures, defined as denticles, on the distal inner margin of the carpus of gnathopods 1 and 2. These structures may have a polygonal pattern or appear as comb scales, and may be arranged in one or more rows.