The influence of ecological and geographical context in the radiation of Neotropical sigmodontine rodents

Abstract

BackgroundMuch debate has focused on how transitions in life history have influenced the proliferation of some clades. Rodents of the subfamily Sigmodontinae (family Cricetidae) comprise one of the most diverse clades of Neotropical mammals (~400 living species in 86 genera). These rodents occupy a wide range of habitats and lifestyles so that ecological context seems relevant to understand the evolution of this group. Several changes in the landscape of South America through the Neogene might have provided vast resources and opportunity to diversify. The aim of this study was to examine whether transitions between i) lowland and montane habitats, ii) open vegetation and forest, and iii) distinct molar architectures are correlated with shifts in diversification rates and to characterize the general pattern of diversification.ResultsBased on a dense taxon sampling of 269 species, we recovered a new phylogeny of Sigmodontinae that is topologically consistent with those of previous studies. It indicates that the subfamily and its major lineages appeared during the Late Miocene. Analyses suggest that vegetation type and elevational range are correlated with diversification rates, but not molar architecture. Tropical lowlands accumulated more lineage diversity than other areas and also supported high speciation rates. Across the radiation the subfamily Sigmodontinae appear to have experienced a decline in diversification rate through time. We detected mixed evidence for lineage-specific diversification rate shifts (e.g., leading to the clades of Akodon, Bibimys, Calomys and Thomasomys).ConclusionWe report that the evolution of habitat preference (considering vegetation type and elevational range) was associated with diversification rates among sigmodontine rodents. We propose that the observed diversification slowdown might be the result of ecological or geographical constraints. Our results also highlight the influence of the tropical lowlands -which might have acted as both “a cradle and a museum of species.” The tropical lowlands accumulated greater diversity than the remainder of the group's range.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0440-z) contains supplementary material, which is available to authorized users.

Geometric morphometrics meets metacommunity ecology: environment and lineage distribution affects spatial variation in shape

“…2; Supplementary material Appendix 5) were reconstructed in Mesquite 2.75 (Maddison and Maddison 2011) following the phylogenetic hypothesis of Parada et al (2015). 2; Supplementary material Appendix 5) were reconstructed in Mesquite 2.75 (Maddison and Maddison 2011) following the phylogenetic hypothesis of Parada et al (2015).…”

Convergence across a continent: adaptive diversification in a recent radiation of Australian lizards

“…The importance of examining other recent widespread radiations (e.g. the Sigmodontinae of South America [58,59]) is therefore evident and will inform our general understanding on the process of continental diversification. As such, the study of recent radiations can provide a window into the origin of biodiversity and how microevolutionary processes ultimately induce macroevolutionary change at a continental scale.…”

El endemismo: diferenciación del término, métodos y aplicaciones

“…3). Sin embargo, al hacer la comparación entre dos de las cinco especies, el ratón T. aureus (3.1 Ma) (Parada et al 2015) sería neoendémica y la paca C. taczanowskii (3.8 Ma) (Upham & Patterson 2012) sería paleoendémica.…”