Gammarus parthicus Stock, Mirzajani, Vonk, Naderi & Kiabi, 1998

Gammarus parthicus Stock, Mirzajani, Vonk, Naderi & Kiabi, 1998: 194 –201, Figs. 13–16.

Locus typicus. Sarabe Abbasabad (33˚55ʹN, 49˚30ʹE), Shahzand, Markazi Province.

Material examined. Holotype and 22 paratypes (ZMA Crust. Amph. 201373); new material: many specimens Dimeh, Esfahan (32˚30ʹN, 50˚13ʹE) (FAIC 111290); many specimens Sudejan, Esfahan (32˚32ʹN, 50˚21ʹE) (FAIC 111291); many specimens Guzdak, Meshkinshahr, Ardebil (FAIC 111293); many specimens, Aluch, Meshkinshahr, Ardebil (FAIC 111294).

Distribution. First record (locus typicus) of this species was from the central Iranian basin, in northern Central Zagros, but recent sampling done by the first author revealed its presence also in the far eastern Alborz localities (Fig. 1).

Ecological notes. Sample from Meshkinshahr was collected in a spring with water temperature of 13ºC and pH of 7.

Taxonomic remarks. The most conspicuous feature of this species – dense long setae on peduncles and flagellum of antenna 2 (much longer than what is drawn in the original description), makes it close to G. pretzmanni and G. komareki . However, presence of 1–2 tiny spines in postero-distal corner of basis in pereopod 7 (Stock et al. 1998, Fig. 15c) makes it easy to distinguish G. parthicus from G. komareki (such spines are present also in G. p re t z - manni). In addition, anterior margins of carpal and meral segments of pereopods are bare in G. parthicus (ibid.), vs. having setae in G. komareki . Setae of both peduncles and flagellum on antenna 2 are highly curled in G. pretzmanni, while in G. parthicus they are slightly curved distally only on the flagellum (ibid., Fig. 13e), such setation pattern can also be seen on pereopod 3 (ibid., Fig. 14e). Moreover, dorsal side of antenna 2 peduncle is almost free of setae in G. parthicus (ibid., Fig. 13e), while in G. pretzmanni the setae are present in dense groups also on the dorsal surface.