Hylaeamys seuanezi (Weksler, Geise & Cerqueira, 1999)

Moreira, Camila Do Nascimento, Ventura, Karen, Percequillo, Alexandre Reis & Yonenaga-Yassuda, Yatiyo, 2020, A review on the cytogenetics of the tribe Oryzomyini (Rodentia: Cricetidae: Sigmodontinae), with the description of new karyotypes, Zootaxa 4876 (1), pp. 1-111 : 25

Hylaeamys seuanezi

Karyotype: 2n = 48 and FN = 60. Autosomal complement: seven metacentric pairs medium to small decreasing in size, and 16 acrocentric pairs large to small decreasing in size. Sex chromosomes: X, a large subtelocentric; Y, a medium metacentric. G-banding was also performed ( Weksler et al. 1999, pp. 449, Fig. 2 ).

A similar karyotype was reported by Andrades-Miranda et al. (2000) for samples from Bahia, Brazil. Karyotype: 2n = 48 and FN = 64. Autosomal complement: one large subtelocentric pair, eight pairs of biarmed chromosomes large to small decreasing in size, and 14 acrocentric pairs large to small decreasing in size. Sex chromosomes: X, a large acrocentric; Y, a medium acrocentric. C-banding metaphases exhibited blocks of constitutive heterochromatin on the pericentromeric region of all autosomes and on the X chromosome. The Y chromosome was entirely heterochromatic. G-banding was also performed. Multiple NORs, varying from three to ten were localized at the telomeric regions of the short arms. According to the authors, the difference in the fundamental number of 60 and 64 was due to the morphology of two autosomal pairs. These variation in fundamental number occurs sympatrically on specimens collected in Bahia, state of Brazil ( Table 5, Fig. 6 ). The same diploid number was reported by Geise & Pereira (2008), but the authors did not provide the fundamental number.

Figures

FIGURE 2. Distribution of diploid and fundamental number of karyotyped specimens of genus Cerradomys. (□) C. akroai; (■) C. goytaca; (ê) C. langguthi; (r) C. maracajuensis; (▲) C. marinhus; (○) C. scotti; (☆) C. subflavus; (l) C. vivoi.

FIGURE 6. Distribution of diploid and fundamental number of karyotyped specimens of genus Hylaeamys. (□) H. megacephalus; (■) H. oniscus; (○) H. perenensis; (l) H. seuanezi; (ê) H. yunganus.