Helobdella stagnalis (Linnaeus, 1758)

(Fig. 16 and Plate VI 1 A,B&C)

Material examined. ZUTC-ann 1037, 1038.

Ahovan, Semnan to Damghan road, Semnan (N 35° 42´01.1½, E 53° 37´03.1½), 1902m, ZUTC 5989. Sheshtamad stone dam, Sabzevar, Khorasan Razavi (N35° 53´51.4½, E 57° 44´13.8½), 1732m, ZUTC 5991. Touskestan to ChaharBagh, Jahan nama protected area, Golestan, (N 36° 37´07.2½, E 54° 16´23.32½), 2149m, ZUTC 6001. Alang sofla, Ramian to Shahroud road, (N 36° 50´35.5½, E 55° 14´55.3½), 1920m, ZUTC 6003. Solouklee protected wetland, Golestan National Park, (N 37° 24΄ 47.8˝, E 55° 46΄ 26.6˝), 1321m, ZUTC 6007. Yashbolagh spring, Tarom, Roudbar-Zanjan mountain road, (N 36° 37΄ 32.7˝, E 49° 07΄ 43˝), 1821 m, ZUTC 6012. Miandoab, between Bashbolakh and Esmaeel Kandi villages, Azerbaijan Gharbi (N 36° 3΄ 8˝, E 46° 6΄), 1314m, ZUTC 6017. Khalkhal to Givi, Ardabil (N 37° 40.9΄ 50˝, E 48° 30.2΄ 21˝), 1717m, ZUTC 6052. Aharchay river, 15 km to Ahar from Meshkin Shahr, Azerbaijan Sharghi, (N 38° 26΄ 49.1˝, E 47° 09΄ 52.1˝), 1284 m, ZUTC 6058. Kaleibar to Jananlou road, Azerbaijan Sharghi, (N 38° 58΄ 15.4˝, E 47° 00΄ 25.4˝), 738 m, ZUTC 6059. Poldasht to Zia-e-din road, Douzaghol, Molakandi, Azerbaijan Gharbi, (N 38° 51΄ 25.9˝, E 45° 51΄ 22.7˝), 1252 m, ZUTC 6061 (Fig.1).

General distribution and habitats. A Holoarctic species (Grosser et al. 2015) also reported by Bennike (1940), Grosser & Pešić (2006) from northeastern and central Iran and Salimi et al. (2011) from western Iran. Living in both freshwater lentic and lotic habitats, mostly in shallow ponds and streams or mountainous springs and usually observed underside of stones, muddy substrates, aquatic vegetation or submerged materials in aggregated numbers.

Descriptive features and remarks. Small flat leeches (1–1.5 cm). Head bulbous with a pair of eyes. A dorsal oval-shaped horny chitinous plate called scutum in pre-clitellar region as a distinctive feature of species. Dorsally, greenish or creamy white and in some cases grayish white with numerous dark pigments arranged randomly. Papillae absent. Ventrally, grayish or pale white. Genital pores separated by one annulus.