Abstract
•Oligoneuriopsis skhounate is an Ibero-Maghrebian endemic mayfly (Ephemeroptera), with a limited number of known localities.•We investigated the distribution and life cycle of the species at the Seybouse River, N.E. Algeria.•Growth and development took place during the warmest period of the year (late spring to early autumn).•There are concerns that O. skhounate is vulnerable to drought, water abstraction and other anthropogenic changes in view of its dependence to permanent habitats.
As an essential component of lotic habitats, aquatic insects have commonly been used as bio-indicators of the ecological integrity of lotic habitats. However, recent large-scale declines have given rise to concerns about freshwater ecosystems functioning correctly. During three consecutive years, we surveyed Wadi Cherf, Upper Seybouse, Algeria, and employed the size-frequency distribution of head capsule width to sketch the life history of Oligoneuriopsis skhounate, an Ibero-Maghrebian endemic mayfly, whose distribution and ecology are not so well-known known. O. skhounate exhibited a seasonal univoltine summer cycle with growth and development taking place during the warmest period of the year (late spring to early autumn). The absence of nymphs during winter and the presence of last instar nymphs from July to November suggested a lengthy egg diapause, following the aestivo-autumnal emergence and reproduction. The study also raises the issue of freshwater biodiversity conservation in North Africa by highlighting the case of O. skhounate, acting as an indicator species of important but vulnerable aquatic ecosystems.