Oecomys superans

Karyotype: 2n = 80 and FN = 108. Autosomal complement: one very large submetacentric pair, 11 metacentric and submetacentric pairs medium to small decreasing in size, three subtelocentric pairs (one large and two medium), and 24 acrocentric pairs large to small decreasing in size. Sex chromosomes: X, a medium submetacentric; Y chromosome presented two different morphologies, a small metacentric, and a small acrocentric (Gardner & Patton 1976, pp. 12, Fig. 5B; Patton et al. 2000; Andrade & Bonvicino 2003). According to Patton et al. (2000), this karyotype was erroneously attributed to O. concolor by Gardner & Patton (1976).