Marine biogeography of southern Australia: phylogeographical structure in a temperate sea-star
Article first published online: 25 NOV 2003
Journal of Biogeography
Volume 30, Issue 12, pages 1787–1796, December 2003
How to Cite
Waters, J. M. and Roy, M. S. (2003), Marine biogeography of southern Australia: phylogeographical structure in a temperate sea-star. Journal of Biogeography, 30: 1787–1796. doi: 10.1046/j.0305-0270.2003.00978.x
- Issue published online: 25 NOV 2003
- Article first published online: 25 NOV 2003
- nuclear DNA;
- climate change;
Aim To test whether marine biogeographical patterns observed at the community level are also important within species. It is postulated that historical hydrogeographic barriers have driven in situ diversification.
Location The intertidal and shallow subtidal zones of southern Australia, New Zealand and nearby islands. Australia's temperate marine communities are characterized by a high degree of endemism and show strong biogeographical structure along an east–west axis.
Methods Phylogeographical analysis of the widespread asteriid sea-star Coscinasterias muricata Verrill across southern Australia and New Zealand. Forty-two samples from 27 locations were included in phylogenetic analyses of mitochondrial (CO1; control region) and nuclear (ITS2) DNA sequences.
Results Analysis of mtDNA revealed a deep phylogenetic split within Australian C. muricata, strongly correlated with latitude. ‘Northern’ haplotypes (latitude ≤ 37.6° S, nine sites, 15 samples) were 7.3–9.4% divergent from ‘southern’ haplotypes (latitude ≥ 37.6° S, 19 sites, 27 samples), consistent with late Pliocene separation. Eastern and western representatives of the ‘northern’ clade were 0.5–1.0% divergent, probably reflecting Pleistocene isolation. The ‘southern’ clade of Australia is also represented in New Zealand, indicating Pleistocene oceanic dispersal. Nuclear DNA (ITS2) sequences yielded relatively little phylogenetic resolution, but were generally congruent with mtDNA-based groupings.
Main conclusions The phylogeographical pattern detected within Australian C. muricata closely resembles marine biogeographical groupings proposed on the basis of community and species distributions. Recurring evolutionary patterns may have been driven by the hydrographic history of southern Australia. Specifically, we suggest that Plio-Pleistocene temperature change and the repeated opening and closure of Bass Strait promoted allopatric divergence and perhaps cryptic speciation in C. muricata.