Evolution and biogeography of New Zealand's longjaw galaxiids (Osmeriformes: Galaxiidae): the genetic effects of glaciation and mountain building
Article first published online: 16 NOV 2007
Volume 53, Issue 3, pages 521–534, March 2008
How to Cite
WATERS, J. M. and CRAW, D. (2008), Evolution and biogeography of New Zealand's longjaw galaxiids (Osmeriformes: Galaxiidae): the genetic effects of glaciation and mountain building. Freshwater Biology, 53: 521–534. doi: 10.1111/j.1365-2427.2007.01917.x
- Issue published online: 16 NOV 2007
- Article first published online: 16 NOV 2007
- (Manuscript accepted 18 October 2007)
- freshwater fish;
- river capture;
1. The biological impact of glaciation in Southern Hemisphere freshwaters is poorly understood. Several large rivers of eastern South Island, New Zealand, represent a mosaic of glaciated and non-glaciated regions, and are thus well-suited for studies of post-glacial recolonization.
2. We conducted mtDNA analyses of South Island's endemic non-migratory longjaw galaxiids Galaxias prognathus and G. cobitinis (Osmeriformes: Galaxiidae) to test hypotheses of post-glacial recolonization, and to assess the vicariant effects of Pleistocene mountain building.
3. We analysed the phylogeography of longjaw cytochrome b sequences from 38 sites in central South Island (n = 83). On the basis of our sampling it seems that G. prognathus and G. cobitinis have a parapatric distribution in the Waitaki River system, their disjunction broadly coinciding with three large post-glacial lakes. Waitaki clades of both species are deeply divergent relative to conspecific taxa in drainages to the north and south.
4. Tests for recent population growth – predicted under post-glacial expansion of G. prognathus– do not refute recent recolonization of streams above glaciated lakes in the Waitaki River drainage. The apparent absence of potential ‘source’ populations from non-glaciated regions suggests a post-glacial population decline for G. prognathus below the Waitaki lakes.
5. Molecular clock calibrations based on several freshwater vicariant events elsewhere in New Zealand supported the geologically-derived hypothesis of Waitaki–Canterbury drainage isolation approximately 300 ka.