Morphological and biochemical evidence that Perinereis cultrifera (Polychaeta : Nereididae) is a complex of species

Paragnath variation was examined in two populations of the epitokous form o f the polychaete Perinereis cultrifera from the English Channel and the Alg erian Mediterranean coast. Populations differ from each other in the mean n umber of paragnaths in groups I, II, III, V and VII-VIII, in the number of teeth per half jaw and in the morphology of paragnaths in the posterior bel t. Individuals of the two populations studied share no common alleles at fi ve loci involved in electrophoretic comparison. The general protein band pa tterns reveal 13 markers that discriminate between the Perinereis individua ls. Congruence of all the reported results agree with the assignment that P . cultrifera is a complex of species, probably more than two.