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Type: Article
Published: 2017-07-17
Page range: 71–92
Abstract views: 84
PDF downloaded: 2

A new species of Deltamys Thomas, 1917 (Rodentia: Cricetidae) endemic to the southern Brazilian Araucaria Forest and notes on the expanded phylogeographic scenario of D. kempi 

Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Animal, Av. Bento Gonçalves 9500, Porto Alegre, RS, Brazil Universidade Federal do Rio Grande, Programa de Pós-Graduação em Biologia de Ambientes Aquáticos Continentais,. Av. Itália km 8, Rio Grande, RS, Brazil
Instituto Nacional de Pesquisas da Amazônia, Programa de Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Av. André Araújo 2936, Manaus, AM, Brazi
Museo Nacional de Historia Natural, 25 de mayo 582, CEP 11000, Montevideo, Uruguay
Universidade Federal da Paraíba, Departamento de Sistemática e Ecologia, Laboratório de Mamíferos, Cidade Universitária, João Pessoa, PB, Brazil
Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Animal, Av. Bento Gonçalves 9500, Porto Alegre, RS, Brazil Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Genética e Biologia Molecular, Av. Bento Gonçalves 9500, Porto Alegre, RS, Brazi
Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Genética e Biologia Molecular, Av. Bento Gonçalves 9500, Porto Alegre, RS, Brazil Departamento de Recursos Ambientales, Facultad de Ciencias Agronómicas, Universidad de Tarapacá, Arica, Chile
Mammalia Akodontini altitudinal gradient cytochrome b dispersal evolution


Deltamys is a monotypic sigmodontine rodent from the Pampas of South America. In addition to the formally recognized D. kempi that inhabits lowlands, an undescribed form Deltamys sp. 2n=40 was recently found in the highlands of southeastern Brazil. In the present study, we perform a phylogeographic reassessment of Deltamys and describe a third form of the genus, endemic to the Brazilian Araucaria Forest. We describe this new species based on an integrative analysis, using complete cytochrome b DNA sequences, karyology and morphology. Bayesian tree recovered two allopatric clades (lowlands vs. highlands) and three lineages: (i) the lowland D. kempi, (ii) the highland Deltamys sp. 2n=40, and (iii) Deltamys araucaria sp. n. Deltamys araucaria sp. n. is karyotypically (2n=34) and morphologically distinguishable from D. kempi (2n=37-38), showing a tawnier dorsum/flank pelage, presence of a protostyle, M1 alveolus positioned anteriorly to the posterior margin of the zygomatic plate, and several other distinguishing characteristics. A phylogeographic assessment of D. kempi recovered two haplogroups with significant differences in skull measurements. This phylogeographic break seems to have been shaped by the Patos Lagoon estuarine channel. The diversification in Deltamys might have been triggered by dispersal of older lineages over different altitudinal ranges in the Paraná geological basin.



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