The blology of Gammarus (Crustacea, Amphipoda) ln the northwestern Atlantlc. VIII. Geographlc distribution of the northern specles

The geographic distribution of the northern Gammarus species of the northwestern Atlantic, arranged from north to south, is as follows: circumpolar, Gammarus wilkitzkii and Gammarus setosus; both shores of the Atlantic, Gammarus duebeni, Gammarus finmarchicus, Gammarus obtusatus, Gammarus oceanicus, and Gammarus stoerensis; western Atlantic, Gammarus lawrencianus, Gammarus mucronatus, and Gammarus tigrinus.It is suggested that the genus Gammarus sensu lato has originated in warm water in the Tethys Sea region, and that the species found in the northwestern Atlantic have radiated from there.