Phoxinusphoxinus (Linnaeus, 1758)

(Fig. 6)

Cyprinus phoxinus Linnaeus, 1758:323 (type locality: Agger River north of Lohmar, 50°50’N, 7°12’E, Nordrhein- Westfalen, Germany).

Cyprinus aphya Linnaeus, 1758:323 (type locality: Agger River north of Lohmar, 50°50’N, 7°12’E, Nordrhein- Westfalen, Germany).

Phoxinus laevis Fitzinger (ex Agassiz), 1832:337 (type locality: Agger River north of Lohmar, 50°50’N, 7°12’E, Nordrhein-Westfalen, Germany).

Phoxinus varius Perty, 1832:719 (type locality: Agger River north of Lohmar, 50°50’N, 7°12’E, Nordrhein-West- falen, Germany).

Material examined

NRM 55112, 5 m, 4 f, 45.8-57.5 mm SL; Germany: Agger River north of Lohmar, 50°50’N, 7°12’E, alt. 59 m. MNHN 2014-0021, 3 m, 55.9-63.1 mm SL; France: Ardennes Stream, Houille, 50°07.7’N, 4°50.4’E, alt. 107 m. MNHN 2014- 2768, 5 f, 53.1-62.6 mm SL; France: Meuse River, Bannon- court, 48°57.5’N, 5°30.2’E, alt. 211 m. MNHN 2014-2769, 2 m, 2 f, 51.3-55.2 mm SL; France: Anger Stream, Circourtsur-Mouzon, 48°16.7’N, 5°42.1’E, alt. 322 m. MNHN 2014- 2743, 2 m, 3 f, 47.6-56.4 mm SL; France: Ornain Stream, Revigny-sur-Ornain, 48°49.4’N, 4°58.9’E, alt. 141 m. MNHN 2014-2757, 2 m, 4 f, 50.2-63.6 mm SL; Seine River, Nod-sur-Seine, 47°45.8’N, 4°34.2’E, alt. 250 m. MNHN 2014-2724, 13 f, 51.5-68.6 mm SL; France: Oise Stream, Gergny, 49°54.5’N, 3°56.1’E, alt. 127 m. MNHN 2014- 2748, 7 m, 2 f, 50.0-63.0 mm SL; France: Beuvron Stream, Ouagne; 47°23.9’N, 3°29.7’E, alt. 163 m .

Material used for molecular analysis

MNHN 2014-0021, 2, tag VAI2 and VAI4; France: Ardennes Stream, Houille, 50°07.7’N, 4°50.4’E, alt. 107 m. (COI: GenBank accession numbers: MT975737, MT975800) . MNHN 2014-2769, 2, tag 1998 and 1999; France: Anger Stream, Circourt-sur-Mouzon, 48°16.7’N, 5°42.1’E, alt. 322 m. (COI: GenBank accession numbers: MT975750, MT975751, 12S: GenBank accession numbers: MT975374, MT975375) . MNHN 2014-2748, 2, tag 1978 and 1979; France: Beuvron Stream, Ouagne, 47°23.9’N, 3°29.7’E, alt. 163 m. (COI: GenBank accession numbers: MT975738, MT975739, 12S: GenBank accession num- bers: MT975367, MT975368) . MNHN 2011-0403, 1, tag 4401; France: Cure Stream, Voutenay-sur-Cure, 47°33.5’N, 3°47’E, alt. 213 m. (COI: GenBankaccessionnumber: MT975790) . MNHN 2011-1141, 1, tag 10871; France: Epte Stream, Guerny, 49°13.1’N, 1°41.3’E, alt. 36 m. (COI: Gen- Bank accession number: MT975714) . MNHN 2014-2743, 1, tag 1992; France: Ornain Stream, Revigny-sur-Ornain, 48°49.4’N, 4°58.9’E, alt. 141 m. (COI: GenBank acces- sion number: MT975747, 12S: GenBank accession number: MT975372) . MNHN 2014-2724, 1, tag 12460, France: Oise Stream, Gergny, 49°54.5’N, 3°56.1’E, alt. 127 m. (COI acces- sion number: MT975729) . MNHN 2011-0400, 1, tag 4413; France: Seine River, Nod-sur-Seine, 47°45.8’N, 4°34.2’E, alt. 250 m. (COI: GenBankaccessionnumber: MT975791) . MNHN 2011-0266, 2, tag 4374 and 4375; France: Saires River, Brillevast, 49°36.7’N, 1°24.4’W, alt. 96 m. (COI: GenBank accession numbers: MT975785, MT975786) . MNHN 2011-1136, 1, tag 10866; France: Seulles River, Tierceville, 49°17.4’N, 0°31.6’W, alt. 9 m. (COI: GenBank accession number: MT975713) . MNHN 2011-0835, 1, tag 4443; France: Golo River, Campitello, 42°30.4’N, 9°19.4’E, alt. 121 m. (COI: GenBankaccessionnumber: MT975796, 12S: GenBankaccessionnumber: MT975389) .

Diagnosis

Phoxinus phoxinus is distinguished from theother French Phoxinus species by its unique nuptial colour pattern. The nuptial male has bars of variable widths crossing Z2 to Z4 and no stripe long Z3 (vs. presence of a stripe in Z3), the bars are black in Z2 and green in Z3 and Z4 (vs. black from Z2 to Z3). Z2 is golden-yellow (vs. light brownish), Z4 green-yellowish (vs. uniform green, yellow or greyish). Lips as well as pectoral, pelvic and anal fin bases are pinkish (vs. red) (Fig. 6A, C). In the nuptal female, Z4 is green (vs. yellow or greyish), and it has a black line in Z5 between the pectoral- and anal fin bases (vs. absent) (Fig. 6B, D). Phoxinus phoxinus is distinguished from P. biggeri by having 75-99 scales in the lateral series (vs. 68-87), a slightly pointed snout (vs. very stout), a subterminal mouth (vs. terminal or slightly subterminal), a straight to slightly concave anal fin margin (vs. straight to convex), and the caudal peduncle depth 2.8- 3.9 times in its length (vs. 2.1-3.4).

Phoxinus phoxinus is distinguished from P. csikii by having a slightly pointed snout (vs. very stout and blunt), and a straight to slightly concave anal fin margin (vs. straight to slightly convex). The nuptial male P. phoxinus is further distinguished by having a pinkish or pale orange belly not extending on the caudal peduncle (vs. greyish to black not extending on the caudal peduncle in P. bigerri; shiny red extending on the caudal peduncle in P. csikii). The nuptial female is distinguished by having a black stripe along Z3 (vs. only bars in P. bigerri).

Nuptial colouration

Male. – Snout and top of head dark brown. Ablack bar on operculum reaching from top of head to branchiostegal rays. Cheeks white. Operculum with a white spot at uppermost, posterior corner. Ayellow spot on lower-most posterior margin of operculum and on suboperculum. Z1 blackish. No stripe long Z3. Bars of variable widths crossing Z2 to Z4, bars black in Z2 and green in Z3 and Z4. Z4 greenish yellow, bars poorly contrasted on Z4. Bars distinct on caudal peduncle. Z5 greyish to blackish. Belly pinkish or light orange. Mouth as well as bases of pectoral, pelvic and anal fins with a pinkish tinge (Fig. 6A, C).

Female. – Z1dark brown, Z2 greyish, a black stripe on Z3 and black bars from Z1 to Z3. Z4 green and Z5 black. Female always display «male» characters: white and yellow spots on operculum and white spots at base of pectoral, pelvic and anal fins (Fig. 6B, D).

Molecular characterization

On the COI marker, P. phoxinus has seven diagnostic sites, including one synapomorphy. However, the Meuse + Rhine and the Seine populations are characterised respectively by five and two diagnostic sites (Tab. II). For the 12S rDNA marker, two diagnostic sites characterise this species: C (vs. T) in position 736 and G (vs. A) in position 796.

Distribution

Phoxinus phoxinus occurs in the Rhine, Meuse and Seine drainages as well as the coastal catchments of Normandy (Fig. 1). It is also found in the Thames and English Channel coastal catchments (Jörg Freyhof, pers. comm.) and these drainages were tributaries of the Channel River during the Pleistocene and Holocene (see Persat and Keith, 1997). In the Rhine drainage, it seems to form hybrid populations with P. csikii, which might be partly natural as both species are expected to form a contact zone, but minnows have also been introduced regionally (Palandačić et al., 2017). It has been introduced in the Golo River in Corsica, in the Weser drainage and in Ireland (Knebelsberger et al., 2015; Palandačić et al., 2017), and maybe elsewhere in Europe.

Vernacular name

The vernacular name of Phoxinus phoxinus is the Eurasian minnow (FAO-FIES, 2018) – Vairon commun in French (Keith et al., 2011). However, as this species is restricted to the Rhine, Meuse and Seine drainages, all ancient tributaries of the Channel River, we suggest to call it the Channel minnow (English), Vairon de la Manche (French).

Remarks

According to the COI tree (Fig. 3A), there are two distinct lineages: the first groups Rhine + Meuse and the sec- ond clade grouping Seine samples. Both clades are separated by a p-distance of 1.5% but we found no difference between both in morphology and colour pattern. We consider both as two evolutionary lineages of a same species.