A new genus of Baetidae (Insecta, Ephemeroptera) from Southeast Asia

A new genus of Baetidae is described from Southeast Asia, Procerobaetis gen. nov. It has a wide distribution reaching from Indonesia (Sumatra) to the Philippines. Two new species are described from Indonesia, P. leptobranchius gen. et sp. nov. and P. petersorum gen. et sp. nov., and one new species from the Philippines, P. freitagi gen. et sp. nov. Procerobaetis gen. nov. is characterized by having seven pairs of elongate, apically pointed gills. At least gills I and II are very slender with strongly extended points, which is unique in Baetidae. Similar gills were described from Leptophlebiidae. Procerobaetis gen. nov. is further characterized by having long, slender legs with extended, slender and slightly bent claws. The antennae posess remarkable spines at the outer, lateral margin, which are maximally developed on segments IX–XI of the flagellum. No spines are present on the posterior margins of abdominal tergites I–VI. COI sequences were obtained from all three of the new species. The genetic distances (Kimura 2-parameter) between these species are between 13% and 20%. Very limited genetic distances of 0% to 1% were found between specimens of the same species. The occurrence of two different species in the same area of Sumatra is discussed