A new species of the genus Squalius Bonaparte, 1837 (Actinopterygii, Cyprinidae) from the Tagus River Basin (Central Spain)

Abstract

A new species of Squalius is described on the basis of morphological and genetic characters from the Gallo River and its tributaries (Tagus Basin) in central Spain. The new species is distinguished from other Iberian Squalius species by a combination of morphometric, meristic and genetic characters, such as wide infraorbital bones that do not cover the adductor mandibulae muscle; seven scales on the upper transversal line; small number of lateral line scales, mean = 39.8 (39-42); a short and wide head, 4.3-4.9 (mean = 4.5) times the standard length; Short pectoral-ventral length, reaching 2.2-2.4 (mean = 2.3) times the standard length. The new species differs from its closer taxa in terms of genetic GTR distances, S. carolitertii and S. pyrenaicus at 20 fixed nucleotide positions (molecular autapomorphies), in the mitochondrial cytochrome b gene. Genetic divergence values for this new species and S. carolitertii and S. pyrenaicus are 3.8% and 6.1% respectively. The new species should be considered Critically Endangered (CR) according to the IUCN Red List Categories.