Revisionary synopsis of the Baetidae (Ephemeroptera) of North and Middle America.

Abstract

Considerable nomenclatural revision of the North and Middle American Baetidae has resulted from comprehensive research aimed at formulating a phylogenetic classification. The 17 Nearctic species in Pseudocloeon not previously assigned to Acentrella or Apobaetis are newly placed in Baetis or Barbaetis. Cloeon in the area is restricted to C. cognatum, while two species previously in Cloeon are placed in Centroptilum and nine in Procloeon, a genus considered for the first time in the Nearctic. Definitions of Centroptilum and Procloeon are modified, both now incorporate species with hindwings and species without hindwings, and 19 species are transferred from Centroptilum to Procloeon. Pseudocentroptilum s. auctt. in North America is synonymized with Procloeon. Neocloeon is recognized as a synonym of Centroptilum s. str. and removed from synonymy with Cloeon. Dactylo baetis is placed in synonymy with Camelobaetidius, and all species, including those from South America, are newly combined. Two species of Baetis are transferred to Acerpenna, and two to Fallceon. A checklist includes 154 currently recognized species among 19 genera in the area, and incorporates 21 new species synonyms and 57 new combinations. The names Baetis armillatus and Baetis cinctutus are substituted for Pseudocloeon parvulum and Pseudocloeon cingulatum, repec tively, which otherwise attain homonymie status. Regional distributions for each species and abbreviated synonymies since 1976 are annotated to the checklist. Brief discussions of each genus include information on species diagnosis, revisionary bases, status, and needs. A guide to all nomenclatural changes and added taxa since 1976 provides the bibliographic sources of all such information and serves as a ready index to name equivalencies resulting from extensive recent and present revisions.