Sperm transfer and occurrence of spermatophore in the Conchostraca Leptestheriidae (Crustacea, Branchiopoda)

Sperm transfer in Conchostraca Leptestheriidae Leptestheria dahalacensis Ru ppel, 1837, a strictly amphigonic species, occurs due to the production in males of an extremely primitive structure. This structure, analogous to spe rmatophores present in most Crustacea, may be observed in the lumen as thin strips of crystalline material. Shortly before mating, sperm produced in t he gonads are released together with the crystalline fibres that serve as a net which helps keep the sperm compact and adherent to the male's body. Th e surface and shape of the so-called spermatophore is described. Mating tim e is partly dependent on the degree of adherence of the spermatophore to th e female's body. The origin and conformation of this primitive structure is assessed in terms of its significance as an adaptive mechanism.