Phylogeny and classification of the Baetodes complex (Ephemeroptera: Baetidae), with description of a new genus

The Baetodes complex is a distinct, monophyletic grouping of neotropical and southwestern North American baetine (Ephemeroptera:Baetidae) genera having subapical setae on the lateral margin of the tarsal claws of the larvae and a distinct distomedial projection on the basal segment of the genital forceps of male adults. The complex comprises Moribaetis sensu stricto, Mayobaetis new status, Prebaetodes new genus, and Baetodes. Moribaetis is the most plesiotypic lineage, and its larvae have autapomorphic labral and frontal interantennal character stales. Mayobaetis shares synapomorphies involving antennal and paraproct armature with Prebaetodes and Baetodes, and its larvae have autapomorphic antennal and cerci character states. Prebaetodes and Baetodes are sister lineages sharing numerous synapomorphies, some of which appear associated with the evolution of more specialized larval clinging behavior in torrential habitats. Prebaetodes is morphologically intermediate between the more plesiomorphic Mayobaetis and the apotypic Baetodes, and its larvae have autapomorphic labral and mandibular character states. Larvae of Baetodes have autapomorphic gill and median caudal filament character states. Within the construct of a strict phylogenetic-classification, the generic concept of Moribaetis is restricted, and Mayobaetis, formerly a subgenus of Moribaetis, is elevated to generic rank. Prebaetodes and its type species, P. sitesi new species, are described from larvae from Colombia and Ecuador. A generic key to the larvae of the Baetodes complex is provided.