New species of the genus Chondrostoma Agassiz, 1832 (Actynopterigii, Cyprinidae) from western Portugal

Abstract

A new cyprinid species endemic to western Portugal, Chondrostoma occidentale sp. n., is described based on fish collected in the small costal drainages of the Rivers Alcabrichel, Sizandro and Safarujo. The new species belongs to a monophyletic clade that also includes C. oligolepis and C. arcasii, with which it shares many molecular and morphological features. However, it can be distinguished from these two Chondrostoma species by a combination of the following characters: 40-43 (x = 40.9) canaliculate scales on the lateral line; 6-7 (x = 6.9) above the lateral line; 2-3 (x = 2.9) scales below the lateral line. The axilary pelvic scale is smaller than or at most equal to the base of the pelvic fin. The coronoid process of the dentary is very thick. The minimum divergence distances in cytochrome b between C. occidentale and C. oligolepis and C. arcasii was “p” = 4.8-5.9%. This new species should be considered Critically Endangered (CR) according to the IUCN Red List Categories.