This species is distinguished from its congeners by the following set of characters: canaliculated scales on the lateral line 43-48 (mean = 45, 1, Md = 45 n = 99); scales above the lateral line 6-8 (mean = 6.9, Md = 7 n = 99); scales below the lateral line 4-5 (mean = 4.3, Md = 4 n = 99); head small (SL/HL> 4.2); high body depth in comparison to caudal peduncle depth (BD/BLD > 2); pharyngeal teeth (6)5/5(6); dentary with short anterior process and high coronoid process. Genetic distances from the other species of Achondrostoma inferred from the mitochondrial cytochrome b gene sequence were: about 7.7 % with respect to A. salmantinum, about 6.5 % with respect to A. occidentale, about 2.2-2.3 % with respect to A. oligolepis, 0.6-0.7 % with A. arcasii (here defined as the Ebro and Mijares, Palancia and Turia drainages), and 6.6 % with Northwestern Duero. This species has one autapomorphy (non-transversion) in the mitochondrial cytochrome b gene (Ref. 128766).