The ecology of a continental evolutionary radiation: Is the radiation of sigmodontine rodents adaptive?

Renan Maestri, Leandro Rabello Monteiro, Rodrigo Fornel, Nathan S. Upham, Bruce D. Patterson, Thales Renato Ochotorena de Freitas

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

Evolutionary radiations on continents are less well-understood and appreciated than those occurring on islands. The extent of ecological influence on species divergence can be evaluated to determine whether a radiation was ultimately the outcome of divergent natural selection or else arose mainly by nonecological divergence. Here, we used phylogenetic comparative methods to test distinct hypotheses corresponding to adaptive and nonadaptive evolutionary scenarios for the morphological evolution of sigmodontine rodents. Results showed that ecological variables (diet and life-mode) explain little of the shape and size variation of sigmodontine skulls and mandibles. A Brownian model with varying rates for insectivory versus all other diets was the most likely evolutionary model. The insectivorous sigmodontines have a faster rate of morphological evolution than mice feeding on other diets, possibly due to stronger selection for features that aid insectivory. We also demonstrate that rapid early-lineage diversification is not accompanied by high morphological divergence among subclades, contrasting with island results. The geographic size of continents permits spatial segregation to a greater extent than on islands, allowing for allopatric distributions and escape from interspecific competition. We suggest that continental radiations of rodents are likely to produce a pattern of high species diversification coupled with a low degree of phenotypic specialization.

Original languageEnglish (US)
Pages (from-to)610-632
Number of pages23
JournalEvolution
Volume71
Issue number3
DOIs
StatePublished - Mar 1 2017
Externally publishedYes

Keywords

  • Disparity through time
  • evolutionary models
  • evolutionary rates
  • macroevolution
  • macroevolutionary adaptive landscape
  • Neotropics
  • nonadaptive radiation
  • tempo and mode of evolution

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Agricultural and Biological Sciences(all)

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