A molecular analysis of the systematics of three Antarctic bivalves

In this paper we performed a molecular analysis of the systematics of three Antarctic bivalve species: Adamussium colbecki, Laternula elliptica, and Y oldia eightsi. The taxonomic position of A. colbecki, that is included in t he family Pectinidae by some Authors, and in Propeamussiidae by others, was studied by analysing 18S rDNA, mitochondrial 12S, 16S rDNA. The results sh owed that A. colbecki belongs to Pectinidae. No element of evidence support s the inclusion of A. colbecki in any other family. Also studied in this sp ecies was a repetitive DNA sequence which shows characters typical of the c entromeric DNAs found in many other eukariotes. In the other two Antarctic species, we investigated only 18S rDNA and compared it with the sequences p ublished in the literature of species belonging to various bivalve subclass es. These molecular data suggest that the subclass to which Y. eightsi belo ngs is primitive, and that L elliptica, which is usually placed among Anoma lodesmata, shows a close relationship with Heterodonta.