ALLOZYME ELECTROPHORETIC TECHNIQUE AND PHYLOGENETIC-RELATIONSHIPS IN 3 SPECIES OF SEPIA (CEPHALOPODA, SEPIIDAE)

Samples of Sepia officinalis, S. orbignyana, and S. elegans from Galic ian waters (NW Iberian Peninsula) were obtained from commercial catche s in three fishing ports. A preliminary screening for 47 and 33 enzyme s in mantle muscle and digestive gland, respectively, was carried out using seven buffer systems. Thirty-seven enzyme loci were resolved fro m these tissues using only two buffer systems. Most enzymes showed equ al or higher activity for the digestive gland than for the mantle musc le in freshly caught samples of S. officinalis and S. orbignyana. The activity of a large number of enzymes decreased faster in the digestiv e gland than in the mantle muscle after 6-12 h at room temperature. Co nsequently, we suggest that mantle muscle rather than digestive gland be used for routine electrophoretic studies in Sepia species obtained from commercial catches. A phylogenetic reconstruction analysis, apply ing the Wagner parsimony method and using the ommas-trephid species Il lex coindetii as outgroup, showed only one most parsimonious tree. S. orbignyana and S. elegans were found to be a sister group. The topolog y agreed with that recently obtained from mitochondrial rDNA sequences , and both molecular data are in line with previous morphological resu lts. They confirm the view that S. orbignyana and S. elegans belong to a different subgenus (Rhombosepion) from that of S. officinalis (Sepi a ''sensu stricto'').