A third European species of grayling (Actinopterygii, Salmonidae), endemic to the Loire River basin (France), Thymallus ligericus n. sp.

Loire grayling was already known to belong to a distinct lineage, compared to other European population, according to molecular data (enzymatic polymorphism, mtDNA sequencing and microsatellites). In this paper, we consider this lineage as a new species, Thymallus ligericus n. sp., which is endemic to the Loire drainage (France). Compared with the other species, T. ligericus n. sp. is characterized by a more elongated body, the presence of a pointed snout and a strait or convex snout profile, a more inferior mouth with a transversal aperture and a fleshier upper lip, usually more than 50 to several hundreds black dots on the flanks, a shorter head (20.0-23.7% SL), smaller occipital and orbital depths of the head (54.8-71.7% HL and 43.5-53.4% HL, respectively) and a shorter horizontal eye diameter (22.6-26.3% HL).