Expanding the Knowledge of Americabaetis Kluge 1992 (Ephemeroptera: Baetidae): Description of three New Species and Supplementary Description of Americabaetis labiosus Lugo-Ortiz and McCafferty 1996.

Abstract

Based on material collected in Brazil, three new species of Americabaetis Kluge are described based on nymphal stage. Two of them, Americabaetis puri sp. nov. and Americabaetis anapes sp. nov., present a remarkable characteristic previously reported only in Americabaetis titthion Lugo-Ortiz and McCafferty: a pair of setose protuberances on meso- and metasterna. They can be distinguished from each other based on the following characteristics: shape of the meso- and metasternum protuberances; shape of the spines on the posterior margin of the abdominal terga; number of denticles on the tarsal claws; gill shape; and number of spines on the paraproct. The third species, Americabaetis urubici sp. nov., can be distinguished, among other things, by the large body size, presence of frontal keel, gills with tracheae pigmented, extending from main trunk to inner and outer margins, and paraprocts with 21 marginal spines. To enhance the knowledge of the group, this paper also provides a supplementary description for the nymphs of Americabaetis labiosus Lugo-Ortiz and McCafferty based on extensive fresh material collected near its type locality. Finally, we present the first interactive identification key for species of the genus occurring in South America, based on the nymphal stage.