ORDER Salmoniformes j FAMILY Salmomdae SUB-F AMIL Y Coregonidae Salmoninae Thymallinae GENUS Oncorhynchus Salmo Salvelinus SPECIES Salmo trutta Salmo salar Fig. 1. (Legendre, 1980). The three main genera (Salmo, Oncorhynchus, Salvelinus) known to day appeared more recently (at the start of the Pleistocene) from this common ancestry (Jones, 1959). The separation of the American and Euro-Asiatic continents and the subse quent succession of glaciation ages of the Pleistocene and recent eras has not only resulted in the differentiation of these three genera but also the appearances of numerous...