LARGE-SCALE RICHNESS PATTERNS, BIOGEOGRAPHY AND ECOLOGICAL DIVERSIFICATION IN CAVIOMORPH RODENTS PATRONES DE RIQUEZA A GRAN ESCALA, BIOGEOGRAFÍA Y DIVERSIFICACIÓN ECOLÓGICA EN ROEDORES CAVIOMORFOS

R. A. OJEDA; AGUSTINA NOVILLO; AGUSTINA A. OJEDA

Biology of Caviomorph Rodents

SAREM

Lugar: Buenos Aires; Año: 2015; p. 121 - 138

Hystricognath rodents probably arrived from Africa and diversified rapidly into major cladesduring the Eocene-Early Oligocene. Caviomorph rodents radiated in different directions involving bodysize, ecomorphological, physiological and behavioral traits which make them convergent to several groupsof mammals. The aim of this chapter is to analyze and integrate the biogeographical and ecological diversificationwithin the phylogeny of the caviomorph major clades, followed by a case study of diversificationof arid-land octodontids. Caviomorph rodents are grouped into four superfamilies (Cavioidea, Chinchilloidea, Erethizontoidea and Octodontoidea), 13 families, 56 genera and 246 species. The major findingsof our contribution are: a) the two macrohabitats with highest species density are the Amazonian and theAtlantic forest; b) approximately 35% of caviomorphs show small or restricted geographic ranges; c) speciesrichness is linked to an effect of area and productivity; d) ?Amazonia? is suggested as the most likelymacrohabitat for the evolution of proto- caviomorphs; e) the most likely proto-caviomorph macronichesare associated with saxicolous modes of life and a diet of grasses, leaves and fruits; f ) the proto- Montearid-land has been suggested as the ancestral habitat of octodontids, followed by their biogeographical andecological diversification associated with contrasting environmental conditions on both sides of the Andes;g) the colonization of a new adaptive zone and expanded geographic range of Tympanoctomys has beenthe result of the evolution of behavioral, ecomorphological, and physiological traits which enabled betterutilization of open xeric habitats, and hypersaline food resources than its close relatives. The caviomorphsrepresent a good research model to explore and disentangle the biogeographical and ecological diversificationof one of the most conspicuous native lineages of South American mammals. Our global analysis andproposed diversification hypotheses highlight some major findings and pinpoint research lines and gapsthat deserve continuing investigations.