Limnetica 40

Among eucyclopinids freshwater copepods, the genus Eucyclops contains several species or species groups whose taxonomic status has not been properly determined and is in need of revision or redescription. Traditionally used meristic characters have recently been deemed insufficient for resolving these problems, particularly in respect of the South American taxa. New, upgraded descriptive standards and molecular tools have contributed greatly to the clarification of some of these cases in both Europe and the Americas. Based on examination of type specimens and museums’ collections, and following currently accepted taxonomic standards, we were able to clarify the status of some problematic South American species of Eucyclops. We provide herein a redescription of three South American species (i.e., E. pseudoensifer, E. breviramatus, and E. subciliatus), each with a history of poorly understood affinities with other American Eucyclops. The nominal Eucyclops neumani, described by Pesta (1927) and originally described from Argentina, was known to contain two subspecies: E. neumani neumani, recorded in Argentina, Paraguay, and Brazil, and E. neumani titicacae (Kiefer, 1957), known only from Peru and Colombia. Based on our analysis, we conclude that E. titicacae is not a subspecies of E. neumani, but a separate species, distinguishable from its closest congeners. We also provide evidence showing that neither E. pseudoensifer nor E. breviramatus are members of the E. serrulatus species group.