Commented checklist of mayflies (Ephemeroptera) of Mongolia

The checklist of Mongolian Ephemeroptera now contains 96 species in 34 genera and 14 families. Based on extensive material collected in July 2005, Ameletus cedrensis, Siphlonurus palaearcticus, Siphlonurus zhelochovtsevi, Acanthametropus nikolskyi, Baetis atrebatinus, Afronurus abracadabrus, Afronurus levis, Sparbarus corniger, and Caenis macronyx are recorded for the first time, in addition to more than 50 new regional records. Literature sources of individual records (including those of preliminary determinations), unambiguous synonyms, taxonomic shifts, some changes of nomenclature and distribution from the chorological point of view are discussed. The Mongolian mayfly fauna consists of large area species (about 1%), Holarctic species (about 12%), Palaearctic species (about 22%), East Palaearctic species (about 60%) and East Palaearctic species so far found only in insufficiently known regions of Mongolia (about 5%).