Hyalella dielaii sp. nov., from São Paulo, Brazil, is herein described and illustrated. Dorsal margin of single ramus of uropod 3, with two marginal groups of three spines, is the main diagnostic characteristic for this new species. Among other distinctive features that may help to distinguish it are the inner plate of the maxilla 1 distinctly long and thin and the dactylus very short of male gnathopod 2 very short.
Crustacea; freshwater anfipods; taxonomy
