The genus Hylaeamys Weksler, Percequillo, and Voss 2006 (Rodentia: Cricetidae: Sigmodontinae) in the Brazilian Atlantic Forest: geographic variation and species definition

• Published in: Journal of mammalogy 2013-12, Vol.94 (6), p.1346-1363
• Main Authors: Brennand, Pamella G. G., Langguth, Alfredo, Percequillo, Alexandre R.
• Format: Article
• Language: English
• Subjects: Age structure; Biological and medical sciences; Biological taxonomies; Chromosomes; cytogenetics; FEATURE ARTICLES; Forestry; Forests; Fundamental and applied biological sciences. Psychology; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; geographic variation; Geography; Karyology; Karyotype; Karyotypes; Mammalia; Mammals; morphology; morphometry; Museums; Natural history; Oryzomyini; Principal components analysis; Qualitative analysis; Rivers; Rodents; Skull; South America; Specimens; taxonomy; Teeth; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Zoology
• ISSN: 0022-2372; 1545-1542
• DOI: 10.1644/12-MAMM-A-312.1

Seven species are included in the genus Hylaeamys. Their limits and distribution, however, are uncertain. We used morphometric analyses performed in univariate (Dice–Leraas diagrams) and multivariate (size-free principal component analysis) approaches, along with qualitative analysis, as well as information on the karyology, to make an assessment on the status of populations of the genus in the Atlantic Forest. On the basis of the evidence we found, it was possible to corroborate the hypothesis that there are actually 2 species in this biome: H. oniscus, a species distributed on the northern bank of the São Francisco River, from the State of Alagoas to the State of Paraíba; and H. seuanezi, which occurs on the southern bank of the São Francisco River, from the southern portion of Bahia State to the northern part of Rio de Janeiro State. Hylaeamys laticeps, the name formerly used for this entity, was allocated to the synonymy of H. megacephalus, a species that inhabits the Cerrado and Amazon Forest biomes. Hylaeamys oniscus exhibits a longer and more robust skull, with a longer rostrum and the 1st upper molar narrower, and a karyotype with 2n = 52 chromosomes and fundamental number (FN) = 62 autosomic arms, whereas H. seuanezi is smaller and more delicate, with a karyotype of 2n = 48 and FN = 60. The São Francisco River and the associated dry vegetation probably have played an important role in the origin of these species and today may still play a role as a barrier to gene flow between these species. Atualmente, sete espécies estão alocadas no gênero Hylaeamys, mas as suas delimitações e respectivas distribuições ainda permanecem incertas, principalmente na Floresta Atlântica brasileira. Através de análises morfométricas, realizadas através de abordagens univariadas (diagramas de Dice-Leraas) e multivariadas (análise canônica discriminante), somadas a análises qualitativas e a informações citogenéticas avaliamos a variação existente entre as populações do gênero ao longo da Floresta Atlântica. Foi possível corroborar a hipótese de que existem duas espécies do gênero neste bioma: H. oniscus, que encontra-se distribuída na margem norte do Rio São Francisco, na Floresta Atlântica ao norte do Rio São Francisco, desde o Estado de Alagoas até o Estado da Paraíba, e H. seuanezi, que se distribuí na margem sul do Rio São Francisco, desde o sul do Estado da Bahia até o norte do Estado do Rio de Janeiro. Hylaeamys laticeps, o nome empregado anteriormente para esta e