Figure 1.

Three scenarios for the evolution of S. troendelagicum populations were studied here, the major difference being the number of times the species has independently originated (once under scenario 1 (a), twice under scenario 2 (b) and four times under scenario 3 (c); see text above for details). The relative branching in scenarios 1 and 2, that is, the assumption that Overhalla and Høylandet are more closely related than Fosnes and Grong, are based on results of the Bayesian cluster analyses.