Abstract
BACKGROUND: The Mediterranean Region of the West Palearctic is one of the most species-rich biomes in the world, hosting a high level of endemism and relict species with important conservation value. The North Africa Atlas Mountains (spanning Morocco, Algeria and Tunisia) belong to a poorly-investigated region of the Mediterranean area, with overlooked aquatic biodiversity; hence, a number of species still remain to be discovered. NEW INFORMATION: The subgenus Antocha (Antocha) Osten Sacken, 1860 is recorded for the first time from Africa, with a description of A. (A.) staryi Keresztes & Mabrouki sp. nov. from hilly regions of the Middle Atlas region, Morocco. The unique design of the male terminalia differentiates well the newly-discovered species from its closely-related and range-restricted A. (A.) phoenicia Thomas and Dia, 1982. This is in contrast with the high intraspecific and geographically poorly-defined variability of the widespread A. (A.) vitripennis (Meigen, 1830), for which morphological variability of male genital structures is discussed.Illustrations of male genital parts, distribution data and key to the species from the West Palearctic area are also provided.