| Sumario: |
The tribe Sciurini comprehends the genera Sciurus, Syntheosiurus, Microsciurus, Tamiasciurus and
Rheinthrosciurus. The phylogenetic relationships within Sciurus have been only partially done, and the relation ship between Mesoamerican species remains unsolved. The phylogenetic relationships of the Mesoamerican tree
squirrels were examined using molecular data. Sequence data publicly available (12S, 16S, CYTB mitochondrial
genes and IRBP nuclear gene) and cytochrome B gene sequences of four previously not sampled Mesoamerican
Sciurus species were analyzed under a Bayesian multispecies coalescence model. Phylogenetic analysis of the
multilocus data set showed the neotropical tree squirrels as a monophyletic clade. The genus Sciurus was para phyletic due to the inclusion of Microsciurus species (M. alfari and M. flaviventer). The South American species
S. aestuans and S. stramineus showed a sister taxa relationship. Single locus analysis based on the most compact
and complete data set (i.e. CYTB gene sequences), supported the monophyly of the South American species and
recovered a Mesoamerican clade including S. aureogaster, S. granatensis and S. variegatoides. These results
corroborated previous findings based on cladistic analysis of cranial and post-cranial characters. Our data sup port a close relationship between Mesoamerican Sciurus species and a sister relationship with South American
species, and corroborates previous findings in relation to the polyphyly of Microsciurus and Syntheosciurus’
paraphyly. Rev. Biol. Trop. 62 (2): 649-657. Epub 2014 June 01.
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