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Evidence of hidden biodiversity, ongoing speciation and diverse patterns of genetic structure in giant Antarctic amphipods


Baird, HP and Miller, KJ and Start, JS, Evidence of hidden biodiversity, ongoing speciation and diverse patterns of genetic structure in giant Antarctic amphipods, Molecular Ecology, 20, (16) pp. 3439-3454. ISSN 0962-1083 (2011) [Refereed Article]

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DOI: doi:10.1111/j.1365-294X.2011.05173.x


Recent molecular research on Antarctic benthic organisms has challenged traditional taxonomic classifications, suggesting that our current perceptions of Antarctic biodiversity and species distributions must be thoroughly revised. Furthermore, genetic differentiation at the intraspecific level remains poorly understood, particularly in eastern Antarctica. We addressed these issues using DNA sequence data for two sibling amphipod species that could be collected on a circum-Antarctic scale: Eusirus perdentatus and Eusirus giganteus. Haplotype networks and Bayesian phylogenies based on mitochondrial (COI, CytB) and nuclear (ITS2) DNA provided strong evidence of multiple cryptic species of Eusirus, with several occurring in sympatry and at least one likely to have a true circum-Antarctic distribution. Within species, gene flow was often highly restricted, consistent with a brooding life history and in some cases suggestive of current or future allopatric speciation. Patterns of genetic structure were not always predictable: one cryptic species showed preliminary evidence of high genetic differentiation across 150 km in eastern Antarctica (FST > 0.47, P < 0.01), yet another was remarkably homogenous across 5000 km (FST = 0.00, P = 1.00). Genetic diversity also varied among cryptic species, independent of sample size (p = 0.00–0.99). These results indicate several hidden levels of genetic complexity in these Antarctic amphipods that are neither apparent from previous taxonomic or ecological studies nor predictable from their life history. Such genetic diversity and structure may reflect different modes of survival for Antarctic benthic organisms during historic glacial cycles, and ⁄ or subsequent re-establishment of populations on the shelf, and highlight our misunderstanding of Antarctic marine species diversity.

Item Details

Item Type:Refereed Article
Keywords:circumpolar distribution, cryptic species, genetic connectivity, glacial cycles, perac-acid crustacean, population structure
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Biodiversity in Antarctic and Southern Ocean environments
UTAS Author:Baird, HP (Dr Helen Baird)
UTAS Author:Miller, KJ (Dr Karen Miller)
ID Code:76033
Year Published:2011
Web of Science® Times Cited:73
Deposited By:IMAS Research and Education Centre
Deposited On:2012-02-22
Last Modified:2012-04-12

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