A new species of the genus Squalius (Leuciscidae, Actinopterygii) from the Sado River basin in Portugal

A new species, Squalius caetobrigus sp. nov., is described based on morphological and genetic traits. Squalius caetobrigus sp. nov. can be distinguished from other Squalius species through a combination of morphometric, meristic and genetic characteristics: 39-42 (▁X=40.7; X ̃=41) canaliculate scales on the lateral line; 6-7 (▁X=7; X ̃=7) scales above the lateral line; 3-4 (▁X=3.1; X ̃=3) scales below the lateral line; short preorbital distance HL/PrOL is 4.2-6.2 (▁X= 5); no contact between the fourth infraorbital bone and the preopercular; short dentary with a very developed coronoid process; the posterior process of the maxilla is long and thin as well as the lower branch of the pharyngeal bone; small pharyngeal plate of the pharyngeal bone and 5 autapomorphies in the mitochondrial cytochrome b gene. Squalius caetobrigus is restricted to the Sado River basin in southern Portugal.