Phoxinus septimaniae

Alexander, Timothy & Seehausen, Ole, 2021, Diversity, distribution and community composition of fish in perialpine lakes – “ Projet Lac ” synthesis report, Eawag: Swiss Federal Institute of Aquatic Science and Technology : 127

The Phoxinus of Lake Chalain in the Jura region of the Rhone drainage, as well as those from tributaries of the Doubs (sampled in Progetto Fiumi), were revealed to be

P. septimaniae .

This is consistent with the known range of this taxon that was recently extended from the Pyrennees to the Jura Rhone [147]. More surprisingly, Progetto Fiumi data revealed that P. septimaniae , nearly completely absent from the lakes in the region, does occur in most streams of northern Switzerland, often together with P. csikii .The exception is the Alpine Rhine (and Lake Constance) where the species seems absent. Interestingly, of all our northern Swiss lake samples, only one individual from Lake Thun was barcoded as P. septimaniae whereas 45 were P. csikii . This is in contrast to Lake Chalain in the Rhone drainage, where P. septimaniae lives in the lake in the absence of P. csikii , and also in contrast to the two alpine lakes, Sils and Poschiavo, where both species co-occur.