Species differentiation of Sepia officinalis and Sepia hierredda (Cephalopoda : Sepiidae) based on morphological and allozyme analyses

Two taxa of commercially exploited cuttlefish, Sepia officinalis and S. hie rredda, are compared for the first time on the bases of quantitative morpho logy and allozyme polymorphisms. Morphometric measurements and meristic cou nts of selected soft and hard (cuttlebone) body characters, with allozyme e lectrophoretic analysis are used. Samples were obtained from north-west Ibe rian Peninsula and Senegalese waters (West Africa). Significant differences in mantle width, arm and hectocotylus length, numbers of ro, vs of reduced suckers on the hectocotylus and in most cuttlebone measurements were found . Canonical discriminant functions of cuttlebone measurements fbr males and females were calculated. Allozyme electrophoresis for 33 presumptive loci showed low levels of genetic variability and 13 diagnostic loci between the two Sepia taxa. The genetic identities (I) in pairwise comparisons of popu lation,, of both taxa were I=0.582-0.596, which are typical values for cong eneric species. These congruent morphological and genetic results strongly suggest that S. officinalis and S. hierredda are different species.