Oligoryzomys stramineus (Bonvicino & Weksler, 1998)

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 : 76

Oligoryzomys stramineus

Karyotype: 2n = 52 and FN = 68. Autosomal complement: nine metacentric pairs (two large, five medium, and two small), and 16 acrocentric pairs (one large and the remaining medium to small decreasing in size). Sex chromosomes: X, a large submetacentric; Y, a medium metacentric ( Maia et al. 1983; Bonvicino & Weksler 1998, pp. 94, Fig. 2 ; Andrades-Miranda et al. 2001a; Weksler & Bonvicino 2005; Geise et al. 2010; Fernandes et al. 2012). Another fundamental number of 69 was reported due to a pericentric inversion in one chromosome of a small acrocentric pair ( Bonvicino & Weksler 1998), and these authors mentioned a fundamental number of 70 apparently due to an inversion in a small acrocentric pair (unpublished data from A.L. Gardner mentioned by Bonvicino & Weksler 1998). These variation in fundamental number occurs on specimens collected in Minas Gerais and Pernambuco, states of Brazil ( Table 9, Fig. 17 ). C-banding metaphases exhibited blocks of constitutive heterochromatin on the pericentromeric region of the majority of the autosomes, but were absent in one large metacentric and on the X chromosome. The Y chromosome was entirely heterochromatic ( 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.