Phylogenetic relationships of the newly described speciesChondrostoma olisiponensis(Teleostei: Cyprinidae)

Phylogenies were generated using mitochondrial cytochrome b and nuclear s-actin gene DNA sequences to infer the phylogenetic relationships of the newly described Chondrostoma olisiponensis. Results indicate that the species is monophyletic with species of the lemmingii -group in mtDNA phylogenies, while it is monophyletic with species of the arcasii -group in the nuclear s-actin trees. This is in agreement with the morphological resemblance of C. olisiponensis to both species groups. Results from nuclear but not mitochondrial DNA indicate that one population could be currently hybridizing with sympatric Chondrostoma lusitanicum. Based on a relaxed clock calibration of cytochrome b, it is estimated that C. olisiponensis split 12·5–7·9 million years ago (middle–upper Miocene) from its most recent ancestor, which coincides with a period of endorrheism in the Iberian Peninsula.