Species assignation amongst morphologically cryptic larval Digenea isolated from New Zealand topshells (Gastropoda: Trochidae).

In New Zealand, a single morphotype, comprising three genetically distinct opecoelid species, infects four sympatric species of trochid snails. Two species (a and b) are specific to Diloma subrostrata while the third (c) is more general, capable of infecting three species, most commonly D. aethiops but never D.