title: Population history, phylogeography, and conservation genetics of the last Neotropical mega-herbivore, the lowland tapir (Tapirus terrestris).
abstract: BACKGROUND
  Understanding the forces that shaped Neotropical diversity is central issue to explain tropical biodiversity and inform conservation action; yet few studies have examined large, widespread species. Lowland tapir (Tapirus terrrestris, Perissodactyla, Tapiridae) is the largest Neotropical herbivore whose ancestors arrived in South America during the Great American Biotic Interchange. A Pleistocene diversification is inferred for the genus Tapirus from the fossil record, but only two species survived the Pleistocene megafauna extinction. Here, we investigate the history of lowland tapir as revealed by variation at the mitochondrial gene Cytochrome b, compare it to the fossil data, and explore mechanisms that could have shaped the observed structure of current populations.
  
  
  RESULTS
  Separate methodological approaches found mutually exclusive divergence times for lowland tapir, either in the late or in the early Pleistocene, although a late Pleistocene divergence is more in tune with the fossil record. Bayesian analysis favored mountain tapir (T. pinchaque) paraphyly in relation to lowland tapir over reciprocal monophyly, corroborating the inferences from the fossil data these species are sister taxa. A coalescent-based analysis rejected a null hypothesis of allopatric divergence, suggesting a complex history. Based on the geographic distribution of haplotypes we propose (i) a central role for western Amazonia in tapir diversification, with a key role of the ecological gradient along the transition between Andean subcloud forests and Amazon lowland forest, and (ii) that the Amazon river acted as an barrier to gene flow. Finally, the branching patterns and estimates based on nucleotide diversity indicate a population expansion after the Last Glacial Maximum.
  
  
  CONCLUSIONS
  This study is the first examining lowland tapir phylogeography. Climatic events at the end of the Pleistocene, parapatric speciation, divergence along the Andean foothill, and role of the Amazon river, have similarly shaped the history of other taxa. Nevertheless further work with additional samples and loci is needed to improve our initial assessment. From a conservation perspective, we did not find a correspondence between genetic structure in lowland tapir and ecogeographic regions proposed to define conservation priorities in the Neotropics. This discrepancy sheds doubt into this scheme's ability to generate effective conservation planning for vagile species.
authors.affiliation: Association Kwata, BP 672, 97335 Cayenne cedex, French Guiana. benoit@kwata.net
authors.forename: Benoit
authors.initials: B
authors.lastname: de Thoisy
authors.forename: Anders Gonçalves
authors.initials: AG
authors.lastname: da Silva
authors.forename: Manuel
authors.initials: M
authors.lastname: Ruiz-García
authors.forename: Andrés
authors.initials: A
authors.lastname: Tapia
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Ramirez
authors.forename: Margarita
authors.initials: M
authors.lastname: Arana
authors.forename: Viviana
authors.initials: V
authors.lastname: Quse
authors.forename: César
authors.initials: C
authors.lastname: Paz-y-Miño
authors.forename: Mathias
authors.initials: M
authors.lastname: Tobler
authors.forename: Carlos
authors.initials: C
authors.lastname: Pedraza
authors.forename: Anne
authors.initials: A
authors.lastname: Lavergne
mesh_terms: D000818:Animals; D003247:Conservation of Natural Resources; D045303:Cytochromes b / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D010527:Perissodactyla / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D058974:Phylogeography
chemical_list: D004272:DNA, Mitochondrial; D045303:Cytochromes b