The Mediterranean region of the Western 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. The subgenus Antocha Osten Sacken, 1860 is recorded for the first time from Africa, with description of Antocha (Antocha) aule Keresztes & Mabrouki sp. n. from hilly regions of the Middle Atlas region, Morocco. Taxonomic revision of the sugenus Antocha from the Western Palearctic area is proposed based on male genital structures, especially in the shape of the outer gonostylus and aedeagus of individuals belonging to populations from geographically distant regions. The unique design of the male terminalia differentiate well the newly discovered species from its closely-related and range-restricted A. phoenicia Thomas & Dia, 1982. This is in contrast with the high intraspecific and geographically poorly defined variability of the widespread Antocha (A.) vitripennis (Meigen, 1830). Illustrations of male genital parts, distribution data, and key to the species from the Western Palearctic area are also provided. The newly discovered species belongs to the Antocha vitripennis Species Group and represents native elements of limited distribution in the Western Palearctic area, likely isolated in a few freshwater ecosystems in a region with severely declining water reserves in the Middle Atlas region, Morocco. Therefore, the discovery of the new species is of special conservation value regarding the freshwater resources from here.