Douro Nase

Pseudochondrostoma duriense is told apart from other members of the genus Pseudochondrostoma by its slightly arched lower jaw, having between 60 and 70 scales along the lateral line, the anal fin has 8+1⁄2 branched rays and the upper body is marked with many black spots. This species has a maximum standard length of 40 cm (16 in).

Pseudochondrostoma duriense is endemic to the Northwestern Iberian Peninsula where it is found from the Douro north and east to the Eo in Portugal and Spain, It has been introduced to the Navia and Nalón rivers in Spain. The Northern straight-mouth nase is found in perennial lowland river channels and larger tributaries. It has colonised some reservoirs where they can reach suitable spawning habitat upstream.

Pseudochondrostoma duriense is classified in the genus Pseudochondrostoma, a name which prefixes Chondrostoma with pseudo- which means "false", applied because although the fishes in this genus are similar in appearance to the nases in the genus Chondrostoma such similarities are due to convergent evolution rather than common ancestry, and are therefore "false". The specific name, duriense , means "of the Douro", a reference to the type locality.