The spring-dwelling amphipod genus Lyurella (Peracarida, Amphipoda): systematics, distribution, and affinity, with description of the second representative from the Black Sea coast region

The hitherto monotypic, crangonyctid genus Lyurella Derzhavin, 1939, despite belonging to one of the most diverse and widely distributed amphipod families in the fresh waters of the Holarctic, is poorly studied due to its rarity and its limited distribution in the Caucasian region. Until now, it has been solely represented by its type species, Lyurella hyrcana Derzhavin, 1939 from the Lankaran lowlands of Azerbaijan and from Lahidjan in northern Iran. In this paper, a new species, Lyurella shepsiensis, is described from a spring in the Shepsi River basin in the Tuapse District of Russia. This is the first representative of this genus from Russia. The new species is closely similar to L. hyrcana, differing mainly in the morphology of the gnathopods and pereopods. This latter species is also redescribed herein, based on new collections that extend its known geographic range.