Abstract
The large sessile tunicate Pyura stolonifera (Pleurogona: Stolibranchiata: Pyuridae), has been regarded as a complex taxon with disjointed distributions, including Australia ( Pyura stolonifera praeputialis ), South Africa ( Pyura stolonifera stolonifera ) and South America (Chile, Antofagasta: Pyura sp., the ‘piure de Antofagasta’), and has been cited under at least five taxonomic combinations. The ‘piure de Antofagasta’ is a competitively dominant species in rocky intertidal habitats and shows a limited geographical range (60–70 km) exclusively inside the Bay of Antofagasta. Using cytochrome oxidase I (COI) mitochondrial sequence data from Pyura specimens of the three taxa we tested whether the Chilean taxon represents: (i) a Gondwana relict; (ii) a more recently divergent species; or (iii) a recently introduced species. The results suggest that the Chilean taxon is a recent introduction to Chile from Australian populations and that Pyura stolonifera praeputialis , from Australia, and the ‘piure de Antofagasta’ are geographical populations of a single species: Pyura praeputialis ; whereas the South African taxon represents a second species: Pyura stolonifera .