title: Evolutionary history and identification of conservation units in the giant otter, Pteronura brasiliensis.
abstract: The giant otter, Pteronura brasiliensis, occupies a range including the major drainage basins of South America, yet the degree of structure that exists within and among populations inhabiting these drainages is unknown. We sequenced portions of the mitochondrial DNA (mtDNA) cytochrome b (612bp) and control region (383 bp) genes in order to determine patterns of genetic variation within the species. We found high levels of mtDNA haplotype diversity (h = 0.93 overall) and support for subdivision into four distinct groups of populations, representing important centers of genetic diversity and useful units for prioritizing conservation within the giant otter. We tested these results against the predictions of three hypotheses of Amazonian diversification (Pleistocene Refugia, Paleogeography, and Hydrogeology). While the phylogeographic pattern conformed to the predictions of the Refugia Hypothesis, molecular dating using a relaxed clock revealed the phylogroups diverged from one another between 1.69 and 0.84 Ma, ruling out the influence of Late Pleistocene glacial refugia. However, the role of Plio-Pleistocene climate change could not be rejected. While the molecular dating also makes the influence of geological arches according to the Paleogeography Hypothesis extremely unlikely, the recent Pliocene formation of the Fitzcarrald Arch and its effect of subsequently altering drainage pattern could not be rejected. The data presented here support the interactions of both climatic and hydrological changes resulting from geological activity in the Plio-Pleistocene, in shaping the phylogeographic structure of the giant otter.
authors.affiliation: Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, United Kingdom. robert.pickles@ioz.ac.uk
authors.forename: R S A
authors.initials: RS
authors.lastname: Pickles
authors.forename: J J
authors.initials: JJ
authors.lastname: Groombridge
authors.forename: V D
authors.initials: VD
authors.lastname: Zambrana Rojas
authors.forename: P
authors.initials: P
authors.lastname: Van Damme
authors.forename: D
authors.initials: D
authors.lastname: Gottelli
authors.forename: S
authors.initials: S
authors.lastname: Kundu
authors.forename: R
authors.initials: R
authors.lastname: Bodmer
authors.forename: C V
authors.initials: CV
authors.lastname: Ariani
authors.forename: A
authors.initials: A
authors.lastname: Iyengar
authors.forename: W C
authors.initials: WC
authors.lastname: Jordan
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D017124:Conserved Sequence / Q000235:genetics*; D045303:Cytochromes b / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D003710:Demography; D004323:Drainage, Sanitary; D019143:Evolution, Molecular; D014644:Genetic Variation; D006239:Haplotypes / Q000235:genetics; D016013:Likelihood Functions; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000235:genetics; D010041:Otters / Q000235:genetics* / Q000254:growth & development; D058974:Phylogeography; D013020:South America; D013997:Time Factors
chemical_list: D004272:DNA, Mitochondrial; D009711:Nucleotides; D045303:Cytochromes b