Trichoptera of northeastern Algeria: New species, noteworthy records, and a review of the genus Hydropsyche (Hydropsychidae)

Freshwater biodiversity in the Maghreb region remains largely unexplored, providing significant opportunities for further discovery. Algerian caddisflies have received relatively little attention. The present study aims to fill gaps in caddisfly taxonomy and distribution by conducting a comprehensive survey of rivers and streams in northeastern Algeria, with a focus on collecting adult caddisflies. Through our research, we identified a total of 28 species from Algeria, and a new caddisfly species, Hydropsyche tenerifa, collected in the Canary Islands, expanding our knowledge of the caddisfly fauna in North Africa. Among these discoveries, we describe 15 new species (H. cherfa, H. makhloufa, H. seybousa, H. algirica, H. dbabcha, H. farrahae, H. guitna, H. chenioura, H. edougha, H. louara, H. vinconi, H. linae, H. nardjissae, Agapetus ferrerasi, A. yasminae) from Algeria and reclassify three subspecies or varieties as distinct species (Wormaldia numidica, Thremma africanum, Mesophylax hoggarensis). In addition, our surveys led to the discovery of three previously unrecorded caddisfly species (Lype reducta, Lepidostoma kumanskii, and Adicella syriaca) in Algeria, as well as the expansion of the known range of seven additional species. These results underscore the importance of the Maghreb's freshwater biodiversity and highlight the need for a more comprehensive understanding of caddisfly taxonomy in the region. By providing a clearer taxonomy and distributional framework for caddisflies, our research establishes a solid foundation for future monitoring and conservation initiatives targeting these important aquatic insects and the ecosystems they inhabit.