Oligoryzomys mattogrossae (Allen, 1916)

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 : 74

Oligoryzomys mattogrossae

Karyotype: 2n = 62 and FN = 64. Autosomal complement: two biarmed pairs medium to small size, and 28 acrocentric pairs (one very large and the remaining large to small decreasing in size). Sex chromosomes: X chromosome presented two different morphologies, a large subtelocentric, and a large acrocentric; Y, a small acrocentric (Myer & Carleton 1981; Bonvicino & Weksler 1998; Andrades-Miranda et al. 2001a, pp. 1084, Fig. 2B ; Weksler & Bonvicino 2005; Pereira & Geise 2007; Di-Nizo et al. 2015; Weksler et al. 2017). A different fundamental number of 66 was reported due to the presence of one small metacentric pair instead of an acrocentric one, moreover, this karyotype also presented a submetacentric Y chromosome ( Andrades-Miranda et al. 2001a). This variation in fundamental number occurs sympatrically on specimens collected in Goiás, state of Brazil ( Table 9, Fig. 17 ). C-banding metaphases exhibited blocks of constitutive heterochromatin on the pericentromeric region of all autosomes, with the exception of the large acrocentric pair. The X chromosome presented pericentromeric heterochromatic blocks varied in size. The Y chromosome was entirely heterochromatic ( Andrades-Miranda et al. 2001a). G-banding was also performed ( Di-Nizo et al. 2015). Multiple NORs, were localized on the short arms of one to three pairs. FISH with telomeric sequences revealed signals exclusively at the ends of all chromosome arms and no interstitial signals were observed ( Andrades-Miranda et al. 2001a).

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 17. Distribution of diploid and fundamental number of karyotyped specimens of genus Oligoryzomys. (r) O. mattogrossae; (■) O. microtis; (○) O. moojeni; (☆) O. rupestris; (▲) O. stramineus; (l) O. utiaritensis.