Karyotypes of Hapalomys and Pithecheir (Rodentia: Muridae) from peninsular Malaysia.

The karyotypes of two Malaysian murids Hapalomys longicaudatus Blyth and Pithecheir melanurus parvus Kloss are reported. Both species have a diploid number of 2n=50 and large metacentric X and large subacrocentric Y chromosomes. The differences found in the autosomal elements may be attributed to pericentric inversions. These karyotypes are also compared with those of two closely related genera, Lenothrix and Chiropodomys. The karyological differences could not be readily explained in terms of simple chromosomal mechanisms.