Zoological Studies

Vol. 52, 2013

The phylogenetic position of the enigmatic Atlantic forest-endemic spiny mouse Abrawayaomys (Rodentia: Sigmodontinae)

Karen Ventura1, Maria José J Silva2, Lena Geise3, Yuri LR Leite4, Ulyses FJ Pardiñas5, Yatiyo Yonenaga-Yassuda1 and Guillermo D'Elía6*

1Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil
2Laboratório de Ecologia e Evolução, Instituto Butantan, São Paulo 05503-000, Brazil
3Laboratório de Mastozoologia, Departamento de Zoologia, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro 20550-013, Brazil
4Laboratório de Mastozoologia e Biogeografia, Departamento de Ciências Biológicas, Centro de Ciências Humanas e Naturais, Universidade Federal do Espírito Santo, Vitória 29075-910, Brazil
5Unidad de Investigación Diversidad, Sistemática y Evolución, Centro Nacional Patagónico, Puerto Madryn 9120, Argentina
6Instituto de Cs. Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia 5090000, Chile

Abstract
Background: The phylogenetic position of the sigmodontine genus Abrawayaomys, historically assigned to the tribe Thomasomyini or considered a sigmodontine incertae sedis, was assessed on the basis of nuclear and mitochondrial DNA sequences obtained from four individuals from different localities in the Atlantic forest of Brazil. Sequences of Abrawayaomys were analyzed in the context of broad taxonomic matrices by means of maximumlikelihood (ML) and Bayesian analyses (BA).
Results:
The phylogenetic position of Abrawayaomys differed depending on the gene analyzed and the analysis performed (interphotoreceptor retinoid-binding protein (IRBP) ML: sister to Thomasomyini; IRBP BA: sister to Akodontini; cytochrome (Cyt) b ML: sister to Neotomys; and Cyt b BA: sister to Reithrodontini). With the sole exception of the BA based on Cyt b sequences, where the Abrawayaomys-Reithrodon clade had strong support, all sistergroup relationships involving Abrawayaomys lacked any significant support.
Conclusions: As such, Abrawayaomys constitutes the only representative so far known of one of the main lineages of the sigmodontine radiation, differing from all other Atlantic forest sigmodontine rodents by having a unique combination of morphological character states. Therefore, in formal classifications, it should be regarded as a Sigmodontinae incertae sedis.

Key words: Akodontini; Atlantic forest; Cricetidae; Phylogeny; Thomasomyini.

*Correspondence: E-mail: guille.delia@gmail.com