title: Biogeography of a southern hemisphere freshwater fish: how important is marine dispersal?
abstract: Galaxias maculatus is one of the world's most widely distributed freshwater fish. This species has a marine-tolerant juvenile phase, and a geographical range extending through much of the southern hemisphere. We conducted phylogeographic analyses of 163 control region haplotypes of G. maculatus, including samples from New Zealand (five locations), Tasmania (one location) and Chile (one location). A lack of genetic structure among New Zealand samples suggests that marine dispersal facilitates considerable gene flow on an intra-continental scale. The discovery of a Tasmanian-like haplotype in one of 144 New Zealand samples indicates that inter-continental marine dispersal occurs but is insufficient to prevent mitochondrial DNA differentiation among continents. The sister relationship of Tasmanian and New Zealand clades implies that marine dispersal is an important biogeographical mechanism for this species. However, a vicariant role in the divergence of eastern and western Pacific G. maculatus cannot be rejected.
authors.affiliation: Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand,National Institute of Water and Atmosphere Ltd (NIWA), PO Box 8602, Christchurch, New Zealand.
authors.forename: J M
authors.initials: JM
authors.lastname: Waters
authors.forename: L H
authors.initials: LH
authors.lastname: Dijkstra
authors.forename: G P
authors.initials: GP
authors.lastname: Wallis
mesh_terms: D000818:Animals; D001483:Base Sequence; D002677:Chile; D017931:DNA Primers / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D005399:Fishes / Q000235:genetics*; D005618:Fresh Water; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D009520:New Zealand; D010802:Phylogeny; D013648:Tasmania
chemical_list: D017931:DNA Primers; D004272:DNA, Mitochondrial