Cerradomys scotti

Karyotype: 2n = 58 and FN = 70. Autosomal complement: seven small metacentric and submetacentric pairs, and 21 acrocentric pairs large to small decreasing in size. Sex chromosomes: X chromosome presented three different morphologies, a large submetacentric (Xa), a large subtelocentric (Xb), and a large subtelocentric shorter than Xb (Xc); Y chromosome presented three different morphologies, a medium submetacentric (Ya), a medium subtelocentric (Yb), and a medium acrocentric (Yc). C-banding metaphases exhibited blocks of constitutive heterochromatin on the pericentromeric region of all autosomes. The X chromosomes presented their short arms and centromeric regions heterochromatic, besides two interstitial bands on its long arms. The three types of Y chromosomes presented their long arms almost entirely heterochromatic. G- and R-banding were also performed. Multiple NORs, varying from three to eleven, were localized on the short arms of acrocentric autosomes (Svartman & Almeida 1992a, pp. 317, Fig. 1). FISH with telomeric sequences revealed signals exclusively at the ends of all chromosome arms and no interstitial signals were observed (Andrades-Miranda et al. 2002).

The same diploid number was reported by Bonvicino et al. (1999), Langguth & Bonvicino (2002) and Bonvicino et al. (2005). These authors reported a different fundamental number of 72 due to a presence of one medium subtelocentric pair instead of a medium acrocentric one, and two males carrying one additional B chromosome. These variation in fundamental number occurs sympatrically on specimens collected in Goiás, state of Brazil (Table 2, Fig. 2).