Gammarus bakhteyaricus Khalaji-Pirbalouty & Sari, 2004

Gammarus bakhteyaricus Khalaji-Pirbalouty & Sari, 2004: 2435 –2440, Figs. 5–7; Ebrahimnezhad, Hosseini & Sari, 2005: 225, Fig. 5.

Locus typicus. Chaghakhor, Chaharmahal Va Bakhtyari Province, (31º55'N, 50º55'E).

Material examined. Holotype, 6 August 2000 (ZUTC Amph. 2030). Paratypes, Bizhgerd spring, Chaharmahal Va Bakhtyari Province (31º47'N, 51º10'E) (ZUTC Amph. 2032).

Distribution. Endemic, restricted to localities in central Zagros: Chaharmahal Va Bakhtyari Province (Khalaji- Pirbalouty & Sari, 2004) and Esfahan (Ebrahimnezhad et al., 2005) provinces (Fig. 1).

Ecological notes. Habitats in high altitudes (2300 m asl) with slow water current are inhabited by this species.

Taxonomic remarks. This species is characterized by presence of 2–3 tiny spines (or “short robust setae”) on distal-ventral corner of first peduncle segment of antenna 1 (Khalaji-Pirbalouty & Sari, 2004, Fig. 5). Similar feature can only be observed in G. shirazinus, although only 1–2 spines are present in this species (Zamanpoore et al., 2010a, Fig. 2). Apart of that, the two species have many differentiating features; most important of them is very long setation of antenna 2 and pereopod 5–7 in G. shirazinus if compared to the former species (ibid., Figs. 2, 4). Gammarus bakhteyaricus may also be confused with G. pseudosyriacus and G. lacustris, however in the latter two species, there are no spines on distal-ventral corner of first peduncle segment of antenna 1.