GENES MEET GEOLOGY: FISH PHYLOGEOGRAPHIC PATTERN REFLECTS ANCIENT, RATHER THAN MODERN, DRAINAGE CONNECTIONS

• Published in: Evolution Vol. 55; no. 9; pp. 1844 - 1851
• Main Authors: Waters, Jonathan M, Craw, Dave, Youngson, John H, Wallis, Graham P
• Format: Journal Article
• Language: English
• Published: United States Society for the Study of Evolution 01-09-2001; Oxford University Press
• Subjects: Animals; Biogeography; Biology; Deoxyribonucleic acid; DNA; DNA, Mitochondrial - genetics; Evolution; Evolution, Molecular; Fish; Fishes - classification; Fishes - genetics; Fresh Water; Freshwater; Freshwater fishes; Galaxias anomalus; Galaxias gollumoides; Galaxias pullus; Galaxias vulgaris; galaxiid; Geography; Geological Phenomena; Geology; Haplotypes; Mitochondrial DNA; New Zealand; Phylogenetics; Phylogeny; REGULAR ARTICLES; river capture; River water; Rivers; Taxa; vicariance; New Zealand; South Island New Zealand; New Zealand, South I., Nevis R
• ISSN: 0014-3820; 1558-5646
• DOI: 10.1554/0014-3820(2001)055[1844:GMGFPP]2.0.CO;2

We used DNA analysis of the freshwater Galaxias vulgaris complex (Pisces: Galaxiidae) to test a geological hypothesis of drainage evolution in South Island, New Zealand. Geological evidence suggests that the presently north-flowing Nevis River branch of the Clutha/Kawarau River system (Otago) once flowed south into the Nokomai branch of the Mataura system (Southland). The flow reversal is thought to have resulted from fault and fold activity associated with post-Miocene uplift. Mitochondrial DNA sequence data (control region and cytochrome b genes; 76 individuals; maximum divergence 7.1%) corroborate this geomorphological hypothesis: The Nevis River retains a freshwater fish species (Galaxias gollumoides; five sites; 10 haplotypes) that is otherwise restricted to Southland (nine sites; 15 haplotypes). There is no indication that the Nevis River lineage of G. gollumoides lives elsewhere in the Clutha/Kawarau system (> 30 sites). Likewise, two widespread Clutha lineages (G. ‘sp D’; G. anomalus–G. pullus) are apparently absent from the Nevis (> 30 sites). In particular, G. ‘sp D’ lives throughout much of the Clutha (12 sites, 23 haplotypes), including a tributary of the Kawarau, but is absent from the Nevis itself. Conventional molecular clock calibrations (based on a minimum Nevis-Mataura haplotype divergence of 3.0%) indicate that the Nevis flow reversal may have occurred in the early-mid Pleistocene, which is roughly consistent with geological data. The broad phylogeographic structure evident in the Clutha system is consistent with the sedentary nature of nonmigratory galaxiids. Our study reinforces the value of combining biological and geological data for the formulation and testing of historical hypotheses. Corresponding Editor: B. Bowen