Holochilus venezuelae (Allen, 1904)

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 : 20

Holochilus venezuelae

Karyotype: 2n = 44 and FN = 56. Autosomal complement: seven metacentric pairs (six large to medium decreasing in size and one small), and 14 acrocentric pairs medium to small decreasing in size. Sex chromosomes: X, a large acrocentric; Y, a small acrocentric. Variation in diploid number (2n = 42–44) were reported due to centric fusions affecting acrocentric pairs, besides the presence of one or two medium-sized supernumerary metacentric chromosomes ( Aguilera & Perez-Zapata 1989, pp. 200, Fig. 2 ; Sangines & Aguilera 1991). These variation in diploid number and the presence of supernumerary chromosomes occurs sympatrically on specimens collected in Portuguesa, state of Venezuela ( Table 4, Fig. 5 ). C-banding metaphases showed that five metacentric pairs had very little pericentromeric heterochromatin, while one medium metacentric pair showed a conspicuous band on the pericentromeric region. The small metacentric pair presented a large pericentromeric heterochromatic block extending to the arms. All acrocentric autosomes presented bands on the pericentromeric region, except for one medium-sized pair, which showed no C-bands. The X chromosome possesses two bands, a thick one on the pericentromeric region and another one on the distal region. The Y chromosome was completely heterochromatic. The small metacentric B chromosomes were almost entirely heterochromatic except for the telomeres. G-banding was also performed ( Sangines & Aguilera 1991).

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 5. Distribution of diploid and fundamental number of karyotyped specimens of genus Holochilus. (■) H. brasiliensis; (□) H. chacarius; (l) H. sciureus; (○) H. venezuelae; (▲) H. vulpinus.