A new species of <i>Speocyclops </i>(Crustacea: Copepoda) from interstitial waters of the eastern Lesser Caucasus
An illustrated description of Speocyclops atropatenae sp. nov. from eastern Lesser Caucasus (Talysh Mountains, at Gosmalyan and the vicinity of Stepanakert [Khankendi ]) is presented. The new species differs from the related S. demetiensis Scourfield, 1932 and S. plutonis Kiefer, 1937 by having a triangular and better developed anal operculum with deep dents (2 to 8) along its outer margin, by a divided genital double-somite, strongly serrated abdominal somites, an elongated distal endopodal P4 segment with the index 1.3 (vs. 1.1 in the two species in comparison), and some other characters. The maxilliped is three-segmented (vs. foursegmented in S. demetiensis); the maxillar endopod two-segmented (vs. one-segmented in S. demetiensis). Speocyclops atropatenae sp. nov. possesses six setae on the second endopodal antennal segment (vs. eight in S. demetiensis), and the ornament on the first endopodal antennal segment is absent (vs. two transverse spinule rows present in S. demetiensis). The new species inhabits interstitial water of mountain streams, and its distribution is the most eastern range in the genus.