Browsing by Author "Parada, Andres"

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    Species groups and the evolutionary diversification of tuco-tucos, genus Ctenomys (Rodentia: Ctenomyidae)
    (2011) Parada, Andres; D'Elia, Guillermo; Bidau, Claudio J.; Lessa, Enrique P.
    We present the most comprehensive study to date of species groups in Ctenomys (tuco-tucos), a species-rich genus of Neotropical rodents. To explore phylogenetic relationships among 38 species and 12 undescribed forms we sequenced the complete mitochondrial cytochrome-b genes of 34 specimens and incorporated 50 previously published sequences. Parsimony, likelihood, and Bayesian phylogenetic analyses were performed using additional hystricognath rodents as outgroup taxa. The basal dichotomy of Ctenomys splits C. sociabilis from the remaining tuco-tucos, within which 8 main species groups were identified: boliviensis, frater, mendocinus, opimus, magellanicus, talarum, torquatus, and tucumanus. Whereas most of these groups refer to previous clades proposed on the basis of chromosomes or morphology, the torquatus and magellanicus species groups are novel taxonomic hypotheses. However, relationships among species groups are poorly resolved. Furthmore, the positions of C. leucodon, C. maulinus, and C. tuconax are conflicting or unresolved, and they might represent additional independent lineages. On the basis of molecular dating, we estimate that most species groups originated approximately 3 million years ago.
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    The population of Ctenomys from the Nacunan Biosphere Reserve (Mendoza, Argentina) belongs to Ctenomys mendocinus Philippi, 1869 (Rodentia: Ctenomyidae): molecular and karyotypic evidence
    (2012) Parada, Andres; Ojeda, Agustina; Tabeni, Solana; D'Elia, Guillermo
    Subterranean tuco-tucos of the genus Ctenomys are caviomorph rodents comprising a complex of over 50 nominal species found in the southern half of South America. The validity of several nominal forms awaits a proper assessment. The population of Ctenomys from Nacunan Biosphere Reserve (Mendoza, Argentina) has been classically considered to represent a distinct species and has been commonly referred as Ctenomys "eremofilus". Based on molecular and cytogenetic analysis we assessed the taxonomic status of the Ctenomys population of Nacunan. Specimens analyzed showed two very similar chromosome complements (2n=48 and 2n=50), the latter being widely distributed in populations of C. mendocinus. Similarly, haplotypes recovered from Nacunan specimens are very similar and sister to those recovered from specimens of C. mendocinus. Considering this evidence we conclude that the individuals of Ctenomys from Nacunan population should be assignable to C. mendocinus.