Cryptic species of rockfishes (Sebastes: Scorpaenidae) in the Southern Hemisphere inferred from mitochondrial lineages

Abstract

We used mitochondrial DNA sequence variation of Sebastes from the southeastern Pacific and three localities in the South Atlantic to address long-standing systematic and evolutionary issues regarding the number of species in the Southern Hemisphere. Sequences of the hypervariable mitochondrial control region were obtained from 10 specimens of S. capensis from South Africa (n = 5) and from Tristan da Cunha Island (n = 5) and 27 of S. oculatus from Valparaiso, Chile (n = 10), and the Falkland Islands (n = 17). Results of the study include (1) significant levels of genetic differentiation among the sampled populations (Φ(ST) = 0.225, P < .000001), thus indicating limited gene flow; (2) corroboration of the existence of two different lineages of austral Sebastes corresponding to S. capensis and S. oculatus; (3) finding that S. capensis is not restricted to Tristan da Cunha and South Africa, but is widespread across the South Atlantic; (4) the position of S. capensis as the ancestral lineage of the austral Sebastes; (5) the existence of a third evolutionary lineage with high levels of genetic divergence, particularly abundant in the southwestern Atlantic, which may be recognized as a third austral species of Sebastes.