Rhabdochona spatulatum,new species (nematoda: Rhabdochonidae) from the freshwater cyprinid fish cyprinion microhpthalmum (day) in quetta division,Pakistan

A new species of rhabdochona is described from the intestine of cyprinid fish collected from khessar stream (hamun river basin) at nushki,quetta division,balochistan. it is characterized mainly by having a spatulate right spicule with ventral barb at posterior end,the left spicule has notched anterior and razor-sharp distal tips,finely striated caudal region,fifteen pairs (10 preanal,5 postanal) papillae in males,bifurcate deirids and conical tail tips in both the sexes. the subgeneric definition of r. (rhabdochona) railleit,1916,r. (filochona) saidov,1954,and r. (globochona) moravec,1972a which were based primarily on egg morphology are considered of little value in determining specific relationships within the genus. the new species may be included in the subgenus rhabdochona (morphological group a,moravec,1975) in the presence of thick-shelled (slightly floated) eggs,which is,therefore,described here as rhabdochona (rhabdochona) spatulatum n. sp. this nematode is the first of the genus recovered from cyprinion microphthalmum (day) from this locality in balochistan.