Oligoryzomys vegetus

According to the Rogers et al. (2009), the karyotype reported by Gardner & Patton (1976) for O. fulvescens from Costa Rica actually represents O. vegetus . Karyotype: 2n = 54 and FN = 68. Autosomal complement: five metacentric and submetacentric pairs (one large and four medium to small), three large subtelocentric pairs, and 18 small acrocentric pairs. Sex chromosomes: X, a medium acrocentric; Y, a small acrocentric (Gardner & Patton 1976, pp. 8, Fig. 3F).