Phoxinus spp

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

Phoxinus spp (minnows)

Until a recent systematic and taxonomic revision of the European minnows (genus Phoxinus ), two species were thought to occur in the region sampled by Projet Lac.The species native and widespread in the northern perialpine region was thought to be the central European Phoxinus phoxinus , and the species native and widespread in the region south of the Alps was thought to be Phoxinus lumaireul . Five other species were known with small distributions in southeastern and southwestern Europe but none of these was thought to occur in the region around the Alps. In 2017, the Phoxinus from around Europe were investigated using molecular markers, resulting in a revision of known species and their distribution ranges and the restoration from synonymy and delineation of several additional species that had been considered synonyms of, mostly, P. phoxinus [147]. The only samples from Switzerland included in the study were from Lake Geneva and the Ticino. The Ticino sample was identified as P. lumaireul as expected. Surprisingly however, the Lake Geneva samples were identified as P. septimaniae and P. csikii . The former was a known and valid species believed to be restricted to Mediterranean coastal streams in southern France [9]. The latter is one of the species restored from synonymy, and otherwise having a wide distribution covering most of the southern and northern Danube basin. Prior to Projet Lac and the genetic analyses of the samples, it was therefore entirely unclear which Phoxinus species occurred in the other lakes of Switzerland north of the Alps.

Phoxinus was not common in Projet Lac catches, despite being previously documented in most lakes across the northern perialpine region. Indeed, among the northern lakes, Phoxinus was recorded only in the cool and oligotrophic lakes Walen, Lucerne,Thun, Brienz, as well as in Neuchatel and Chalain. Additionally, Phoxinus were collected from lakes Sils (Danube catchment) and Poschaivo (Po catchment). Barcoding of Phoxinus collected from these lakes and from several streams sampled by Progetto Fiumi in all major catchments revealed the existence of four deeply divergent mitochondrial lineages of Phoxinus that conform to three of the described and valid species plus one lineage that was defined by Palandačić et al [147] but remains undescribed.