Genetic differentiation in three Sepia species (Mollusca: Cephalopoda) from Galician waters (north-west Iberian Peninsula)

7 páginas, 2 figuras, 3 tablasThe systematics of the genus Sepia is not yet\udclear. Morphological evidence has led to S. officinalis\udLinnaeus, 1758 being considered as belonging to the\udsubgenus Sepia sensu stricto, and S. orbignyana F6russac,\ud1826 and S. elegans Blainville, 1827 as belonging to\udthe subgenus Rhombosepion. Samples of 30 individuals\udof S. officinaIis and S. orbignyana from both sides of an\udoceanographic boundary off the north-west Iberian\udPeninsula, and a sample of S. elegans from the northern\udside, were collected in 1993-1994. Allozyme electrophoresis\udfor 32 presumptive loci revealed low levels\udof genetic variability for the three Sepia species (mean\udexpected heterozygosity estimates were < 0.052). No\udsignificant differences in allozyme frequencies were detected\udamong populations of either S. officinalis or S.\udorbignyana. The genetic identities (I) of S. officinalis and\udS. orbignyana (I = 0.12) and of S. eIegans (I = 0.13)\udwere significantly different from that of S. orbignyana\udand S. elegans (I = 0.49). The former are typical of\udvalues for confamilial genera, and a new generic status\udis proposed for the latter two species, which become\udRhombosepion orbignyana (F6russac, 1826) and R. elegans\ud(Blainville, 1827).This research was\udsupported by an equipment grant (University of Vigo) to M. Horjales,\udand the Projects AIRI-CT92-0573 (EC) and AMB94-0371\ud(CICYT, Spain) to A.S. Sections of this paper fulfil the PhD requirements\udfor M.P.-L. (University of Vigo), who received a scholarship\udfrom Xunta de Galicia (Spain).Peer reviewe