Ecdyonurus aurasius sp. nov. , a micro-endemic species reported from several streams within the Aurès Mountains (north-eastern Algeria), is described and illustrated at nymphal, subimaginal and imaginal stages of both sexes. Critical morphological diagnostic characters distinguishing the new species are presented, together with molecular affinities as well as notes on the biology and distribution of the species.

Besides their important ecological role in flowing waters, blackflies (Diptera: Simuliidae) may pose medical and veterinary risks. For seventeen months, we surveyed the blackflies of ten localities across the Aures Mountains, in the Saharan Atlas, Algeria, and recorded eight taxa (i.e. species, species groups or species complexes). High altitude sites were dominated by the Simulium ornatum (Meigen, 1818) group, whereas sites located on the southern slope of the Aures Mountains were occupied by the eurytopic Simulium velutinum (Santos Abreu, 1922) complex and the thermophilic, pollutant-tolerant Simulium ruficorne Macquart, 1838 ‘A’ morphotype.Co-inertia analysis was used to determine the relationship between a species’ abundance and habitat types. The co-inertia analysis revealed a likely co-structure between blackfly assemblages and measured environmental descriptors (water temperature, conductivity, current velocity, bed width, etc.) in sampled habitats. This confirmed the importance of altitude as a driver of blackfly distribution. Our results also showed that there has been an increase in anthropogenic pressures on the vulnerable freshwater biota of the Aures Mountains.

The hitherto unknown larva of Limnephilus barbagaensis Malicky, Sekhi & Lounaci 2019, micro-endemic of the Aures Mountains (Mounts des Aures, Algeria), is described. The diagnostic features of the species are listed, illustrated, compared with those of similar species, and some information on the ecology is included. In addition, the first record of Hydropsyche siltalai Döhler 1963 in the Aures Region and Northeast Algeria is also reported.

The caddisfly fauna of Algeria is poorly known and the few sporadic studies available were carried out decades ago. In this study, caddisfly larvae, pupae, and adults were collected in 11 stream localities from the Aures region, northeastern Algeria. Caddisflies were regularly sampled between April 2018 and February 2020. Two genera are new records to Algeria: Plectrocnemia and Setodes. In addition, four Trichoptera species are new to the Algerian fauna: Tinodes dives, Hydropsyche modesta, Plectrocnemia conspersa and Setodes acutus. Future caddisfly surveys in the region will doubtlessly contribute significantly to the incompletely known Trichoptera fauna of Algeria.