Phylogeography of the Patagonian otter Lontra provocax: adaptive divergence to marine habitat or signature of southern glacial refugia?
A number of studies have described the extension of ice cover in western Patagonia during the Last Glacial Maximum, providing evidence of a complete cover of terrestrial habitat from 41oS to 56oS and two main refugia, one in south-eastern Tierra del Fuego and the other north of the Chiloe Island. However, recent evidence of high genetic diversity in Patagonian river species suggests the existence of aquatic refugia in this region.
Here, we further test this hypothesis based on phylogeographic inferences from a semi-aquatic species that is a top predator of river and marine fauna, the huillin or Southern river otter (Lontra provocax).
Results:
We examined mtDNA sequences of the control region, ND5 and Cytochrome-b (2151 bp in total) in 75 samples of L. provocax from 21 locations in river and marine habitats.
Phylogenetic analysis illustrates two main divergent clades for L. provocax in continental freshwater habitat.
A highly diverse clade was represented by haplotypes from the marine habitat of the Southern Fjords and Channels (SFC) region (43o38'to 53o08'S), whereas only one of these haplotypes was paraphyletic and associated with northern river haplotypes.
Conclusions:
Our data support the hypothesis of the persistence of L. provocax in western Patagonia, south of the ice sheet limit, during last glacial maximum (41oS latitude).
This limit also corresponds to a strong environmental change, which might have spurred L. provocax differentiation between the two environments.
Author: Juliana ViannaGonzalo Medina-VogelClaudio ChehebarWalter SiefeldCarlos OlavarriaSylvain Faugeron
Credits/Source: BMC Evolutionary Biology 2011, 11:53
Published on: 2011-02-28
Copyright by the authors listed above - made available via BioMedCentral (Open Access). Please
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