Phylogeny and Evolution of Body Size in Caviidae (Rodentia, Hystricognathi, Cavioidea): Approach of a Combined Analysis with Morphology and Molecular Data

MARÍA E. PÉREZ; NÉSTOR G. BASSO; J. ALFREDO HOLLEY; MARCELO WEKSLER

Philadelphia

Congreso; AMERICAN SOCIETY OF MAMMALOGISTS 93rd ANNUAL MEETING; 2013

AMERICAN SOCIETY OF MAMMALOGISTS

Caviidae forms part of the highly diverse South American hystricognath rodents and includes three major living lineages: Caviinae (cavies), Dolichotinae (maras), and Hydrochoerinae (capybaras). Caviids have the broadest range of body size among extant rodents but so far the evolution of body size has never been properly analyzed in this group. In this contribution, we include new sequences of two genes for extant caviids and integrate them with published sequences of four other genes as well as a recently published morphological dataset scored for extant and extinct taxa (including the extinct "eocardiids" which form the successive sister groups of Caviidae). The resultant topologies are used to infer the evolution of body size in this group through the optimization of body mass estimates. The analysis reveals the presence of a basal stability in the evolution of body size across ?eocardiids? and a much more dynamic history of body size change within the crown group Caviidae. Hydrochoerines and dolichotines increased their body mass but these are two independent and temporally separated events. In turn, caviines reduced their body size during the middlelate Miocene, at the same time that major environmental changes altered the South American biomes.