Dicercomyzon femorale, Demoulin, 1954

Kluge, Nikita J., 2022, Taxonomic significance of microlepides on subimaginal tarsi of Ephemeroptera, Zootaxa 5159 (2), pp. 151-186 : 154

Dicercomyzon femorale

= D. costale , syn. n.

The Afrotropical species Dicercomyzon femorale Demoulin 1954a (the type species of Dicercomyzon Demoulin 1954 ) was originally described as larvae and reared female subimago from Congo. The species Dicercomyzon costale Kimmins 1957 was originally described as imagines, subimagines and larvae from Gold Coast (recently Ghana ), Tanganyika Territory (recently Tanzania ) and Nyasaland (recently Malawy ). It was separated from D. femorale by the dark band along the costal margin of the wing, which is absent on the subimaginal wing of the holotype of D. femorale . The reason of this difference is that the dark band on the costal margin of the wing is visible on yellowish background of the larval protopteron, than becomes invisible on brown background of the subimaginal wing, and than becomes visible again at later period of subimaginal development, when the imaginal cuticle gets its intensive pigmentation and becomes visible through the brown subimaginal cuticle; in imago this band is dark brown, in contrast to colorless rest part of the wing ( Kimmins 1957: fig. 1). Demoulin (1954) examined only the female subimago which died just after emergence and had uniformly brown wings. Kimmins (1957) was able to examine only immature larvae, late subimagines and imagines, in all of which the dark band was visible. These authors suggested to separate larvae of D. femorale and D. costale by shape of the small paired protuberances between fore protoptera, which Kimmins (1957) reported as «processes of the wing-pads» and Demoulin (1964b) reported as «calus du mésonotum». Actually , these protuberances are projected dorsally, and their visible shape depends on angle of view and/or compression of the slide.

Material examined: UGANDA: Kanungu District: river Ishasha , 15.VII.2007, coll. N.Kluge: 1 larva ; ibid., river Munyaga below Bwindi National Park , 21–25.VII.2007, coll. N. Kluge: 1 L/S ♂ , 1 L/S ♀, 53 larvae; Kasese District, Kiburara, river Nyamagasan , 8–13.VIII.2007, coll. N. Kluge: 2 L-S-I ♂, 29 larvae . ZAMBIA: Mwinilunga, rivers West Lunga and Mudanyama , 4–17.VIII.2014, coll. N. Kluge & L. Sheyko: L-S-I ♀, 24 larvae . TANZANIA: Njombe Region, Great Ruaha river above Mfumbi , 26.VII–3.VIII.2016, coll. N. Kluge & L. Sheyko: L-S-I ♂ , L-S/I ♂, 2 larvae; ibid., 13–15.VIII.2017: 4 larvae ; river Msosa (tributary of Great Ruaha), Msosa Camp 9 km S Mbuyuni 5–10.VIII.2017, N. Kluge & L. Sheyko: L-S-I ♂ ; Uluguru Mountains, basin of river Ruvu, Kinole , 27–30.VII.2017, coll. N. Kluge & L. Sheyko: L/S ♂ .