Geographical distribution and ecological diversification of South American octodontid rodents

AGUSTINA OJEDA; AGUSTINA NOVILLO; OJEDA RICARDO ALBERTO; SERGIO A ROIG-JUÑENT.

JOURNAL OF ZOOLOGY (1987)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2012

0952-8369

Caviomorph rodents represent one of the most distinctive groups of mammals insouthern South America drylands; they colonized South America from Africa viatrans-oceanic dispersions in the Eocene (40?50 Ma) and underwent an extraordinaryecological radiation after their arrival, thus making this group of greatinterest for biogeographic and evolutionary studies. The aim of this article was toprovide a working hypothesis regarding the biogeographical history and ecologicaldiversification of one of its conspicuous families, the Octodontidae. We reconstructthe evolutionary theater where their ecological diversification took place,and potential events of dispersal, vicariance and extinctions. We analyzed thehistorical biogeography of the Octodontidae across the eight ecoregions wherethey occur, based on species phylogeny and divergence times. Four approacheswere used to reconstruct ancestral area: (1) Statistical Dispersal?Vicariance Snalysis(S-DIVA); (2) Bayesian binary MCMC analysis implemented in ReconstructAncestral State in Phylogenies (RASP); (3) Fitch optimization method; and (d)weighted ancestral area analysis (WAAA). Parsimony ancestral state reconstructionswere implemented in order to explore the evolutionary history of anecological character, mode of life. We propose the northern portion of the Montedesert ecoregion as the ancestral area in the evolution of the Octodontidae, withsubsequent dispersal and enlargement of the family geographic range. The evolutionof their ecological specialization (i.e. modes of life) suggests an ambiguousancestral condition (saxicolous, generalist terrestrial, semifossorial) linked tospecies adaptation to arid environments, with fossoriality appearing later in octodontidevolution. The evolution of the Octodontidae is associated with contrastingenvironmental conditions (i.e. climate and vegetation) produced by theAndean Uplift between eastern and western sides.