A Comparative Study of the Chromosomes of Mytilus Edulis and Mytilus Galloprovincialis

Abstract

The exact form of the taxonomic relationship between the common or blue mussel, Mytilus edulis L., and Mytilus galloprovincialis Lmk, the Mediterranean mussel, has been the subject of considerable scientific interest in recent years (for a review see Gosling, 1984). While the origins of this separation into two species rests with the original descriptions by Linnaeus and Lamarck (e.g. Soot-Ryen, 1955), interest was stimulated in recent times through the discovery by Hepper (1957) of an ‘unusual’ type of mussel at Padstow in Cornwall which, on the basis of morphological criteria, he identified as M. galloprovincialis (see also Lewis & Seed, 1969). This discovery was followed by a series of electrophoretic investigations providing evidence that the so-called ‘Padstow mussel’ exhibits genetic affinities with M. galloprovincialis from the Mediterranean (Ahmad & Beardmore, 1976; Skibinski, Ahmad & Beardmore, 1978; Skibinski, Cross & Ahmad, 1980). In her recent review paper on the systematic status of M. galloprovincialis in western Europe, Gosling (1984) considers information from morphological, cytological, immunological, electrophoretic and hybridization studies and concludes that M. galloprovincialis is a ‘form’ or ecotype of M. edulis.