Oligoryzomys microtis (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 microtis

Karyotype: 2n = 64 and FN = 66. Autosomal complement: one large submetacentric pair, one small metacentric pair, and 29 acrocentric pairs medium to small decreasing in size. Sex chromosomes: X, a medium subtelocentric; Y chromosome presented two different morphologies, a small metacentric, and a small acrocentric ( Gardner & Patton 1976, pp. 8, Fig. 3B ; Aniskin & Volobouev 1999; Patton et al. 2000). Another fundamental number of 64 was reported for a sample from Mato Grosso, state of Brazil, due to the presence of one large acrocentric pair instead of a submetacentric one ( Di-Nizo et al. 2015). C-banding metaphases exhibited blocks of constitutive heterochromatin on the pericentromeric region of the autosomal pairs, with the exception of one the large submetacentric pair and five acrocentric pairs of medium-sized. The X chromosome presented the short arm entirely heterochromatic. The metacentric Y chromosome was entirely heterochromatic ( Aniskin & Volobouev 1999). G-banding was also performed ( Aniskin & Volobouev 1999; Di-Nizo et al. 2015).

Figures

FIGURE 3. Distribution of diploid and fundamental number of karyotyped specimens of genus Euryoryzomys. (■) E. emmonsae; (□) E. lamia; (▲) E. macconnelli; (○) E. nitidus; (l) E. russatus; (r) Euryoryzomys sp. nov.; (ê) Euryoryzomys sp..