Hylaeamys oniscus

Karyotype: 2n = 52 and FN = 62. Autosomal complement: six metacentric and submetacentric pairs medium to small decreasing in size, and 19 acrocentric pairs large to small decreasing in size. Sex chromosomes: X, a large acrocentric; Y, a small acrocentric (Maia 1990, pp. 379, Fig. 1A; Andrades-Miranda et al. 2000). 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 five to nine were localized at the telomeric regions of the short arms of acrocentric pairs (Andrades- Miranda et al. 2000).