Chromosomal characterization of the Formosan striped squirrel Tamiops maritimus formosanus (Mammalia, Rodentia)

Chromosomes of the Formosan striped squirrel Tamiops maritimus formosanus were analyzed with conventional and silver staining and G- and C-banding technique. The diploid chromosome number (2n) and fundamental autosomal arm number (FN) were 38 and 68, respectively. Karyotype consisted of seven pairs of metacentrics (nos. 1-7), nine pairs of submetacentrics or subtelocentrics (nos. 8-16), two pairs of acrocentrics (nos. 17 and 18), a medium-sized submetacentric X chromosome, and a small acrocentric Y chromosome. All autosomes and the X chromosome carried centromeric constitutive, heterochromatin, but the Y chromosome was entirely euchromatic. In the short arm of no. 17 chromosomes, the prominent satellite structure with its long stalk, which corresponded to the nucleolus organizer region (NOR), was observed, suggesting that it could have been shared with other squirrel species through the evolutionary process.