Systematics of the mayfly taxon Acentrella (Ephemeroptera: Baetidae), with description of new Asian and African species

Abstract

This paper continues publications on phylogenetic analysis of Ephemeroptera according to the approach, which is named here “cladoendesis”. A new term “microlepides” is suggested for peculiar cuticular texture. Autapomorphies of Liberevenata in genital structure are described, new terms “unistyliger”, “penial bridge” and “gonovectis” are introduced. Autapomorphy of Anteropatellata in tibial structure is re-defined, and a new circumscriptional taxon name Protopatellata taxon n. is established. In Anteropatellata, the following new subsequently subordinated holophyletic taxa are established and characterized: Baetovectata taxon n., Baetungulata taxon n., Baetofemorata taxon n. and Baetosternata taxon n. A new typified name Acentrellini tribus n. is introduced, to form a hierarchical name Acentrella/fg1 for a taxon belonging to Baetofemorata-non-Baetosternata. System of Acentrella/fg1 is revised. All Holarctic representatives of Acentrella/fg1 are temporarily placed to a plesiomorphon Acentrella/fg2. Key to larvae and male imagoes of Palearctic species of Acentrella/fg2 is given; they are divided into four species groups. Group lapponica is a plesiomorphon, characterized by presence of hind wings; larvae, subimagoes, imagoes and eggs are described for lapponica [Acentrella], charadra [Acentrella] and chantauensis [Baetis]; feropagus [Acentrella], known as larvae only, is redescribed basing on material from far north-east of Russia; comments on joosti [Baetis] are given. Group fenestratum includes a single species fenestratum [Pseudocloeon]; larvae, subimagoes, imagoes and eggs are described. Group inexpectatumincludes 2 species — inexpectatum [Pseudocloeon] and gnom [Pseudocloeon]; their larvae, subimagoes, imagoes and eggs are described. Group sibiricum includes 3 species — sibiricum [Pseudocloeon], diptera sp.n. [Acentrella] (new species from Siberia and Russian Far East) and scabriventris sp.n. [Acentrella] (new species from Kyrgyzstan and Tajikistan); their larvae, subimagoes, imagoes and eggs are described. African and Oriental representatives of Acentrella/fg1 constitute a holophyletic taxon Jubabaetis/g1 characterized by an autapomorphy in structure of left mola. Jubabaetis/g1 is divided to African taxon Tanzaniops/g(1) and Oriental taxon Jubabaetis/g2. A new species lunamontana sp.n. [Acentrella (Tanzaniops)] is described as larvae, subimagoes and imagoes from Uganda. Holophyletic taxon Jubabaetis/g2 is divided into a plesiomorphon Liebebiella/g(1) and holophyletic taxa Jubabaetis/g3 and Platybaetis/g(1). Three species of Liebebiella/g(1) are described as larvae, subimagoes and imagoes: verum [Pseudocloeon] (= deigma [Liebebiella], syn.n.), bispinosa sp.n. [Acentrella (Liebebiella)] and cylindroculata sp.n. [Acentrella (Liebebiella)] (new species from Sulawesi). Two species of Platybaetis/g(1) from Sulawesi are described as larvae, subimagoes and imagoes: mamasae sp.n. [Platybaetis] and wallacei [Platybaetis].