Cerradomys scotti (Langguth & Bonvincino, 2002)

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 : 9

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 ).

Figures

FIGURE 1. Collection localities of Oryzomyini species analyzed in this work. (1) Claúdia, Mato Grosso state; (2) and (3) Rio Japurá, Amazonas state; (4) and (5) Rio Içá, Amazonas state.

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.