identification snails of dez river in khuzestan province and introduction two new records from iran

abstract collection and identification snails of dez river in khuzestan province in iran has been investigated in 2012-2013. for the first time, 29 snail species are identified in dez river in khuzestan, which they belong to 15 genera from 10 families identification was done according to morphometric characters including shape, size of shell, dextral and sinistral position of the shell, operculum, aperture, radula, mucus colour, respiratory pore, keel, renal ridge and reproduction system. the most and least distribution among identified snail species are 18 and 8 species belong to 4 and 2 stations respectively from dez river, which they are 20/82 kilometers away from each other. the most commonly distributed family is thiaridae with 8 species melanopsispraemorsa, melanopsis costata, melanopsis doriae melanopsis nodosa, melanopsis subtingitana, melanoides pyramis, melanoides tuberculata thiara scabra. bulinus truncates and lymnaea truncatula are identified as the most frequent and has medical importance. melanopsis subtingitana annandale, 1918 and gyraulus huwaizahensis species are reported for the first time from iran.