Ichthyomys pittieri, a semiaquatic rodent, has 92 chromosomes. This is the highest number of chromosomes known in mammals.
Ichthyomys pittieri, belonging to the Cricetinae subfamily, is a rare rodent species found in Venezuela. Karyotype analysis using conventional staining and banding techniques revealed a diploid chromosome number (2n) of 92. This finding distinguishes Ichthyomys pittieri from other mammals, which generally have lower chromosome numbers. The research identifying this was published, analyzing the mitotic and meiotic chromosomes of specimens found in Venezuela. The high chromosome number is a significant characteristic of this particular species.
