Two new genera of Baetidae (Ephemeroptera) from Borneo (East Kalimantan, Indonesia)

Two new genera of Baetidae are described from East Kalimantan (Borneo): Asiobaetodes n.gen. and Acerobiella n.gen. Both genera are monospecific and only known from a very restricted area. They are highly adapted to fast flow and are closely related to Oriental genera Liebebiella Waltz & McCafferty, 1987 and Platybaetis Müller-Liebenau, 1980. Asiobaetodes is characterized by five pairs of ventrally orientated gills and tubular accessory gills at the bases of mouthparts and forelegs; these characters are also present in the Panamerican genus Baetodes Needham and Murphy, 1924 and the African genus Afrobaetodes Demoulin, 1970. The study of the mouthparts clearly indicates that the similarities must be considered as homoplasies. Acerobiella is characterised by its dorsal armature, especially the spike tubercles turned upwards on tergum II, which constitutes a unique character among the Baetidae