Chromosomal analysis of small mammals from Southwestern Nigeria.

Interesting small mammal diversity is currently being uncovered in Nigeria, much of it through molecular analyses. The cytogenetic aspects of this diversity, however, remain largely unknown. In this study, diploid number and chromosome morphology viewed on Giemsa-stained slides for seven small mammal species trapped in Southwestern Nigeria are reported. The specimens were also sequenced for cytochrome b to assist in making accurate taxonomic designations. To our knowledge, chromosomal information is presented for four of these small mammal species for the first time from populations within Southwestern Nigeria. The respective diploid numbers detected in this study for Lophuromys sikapusi and Dasymys sp. differ from diploid numbers published for these species in previous studies. Cytochrome b sequencing helped us to correctly identify Mastomys erythroleucus (2n = 38), where specimens with this same chromosome number in our study area were erroneously assigned to other Mastomys species. Cytogenetic data combined with other lines of scientific evidence will help us appreciate and understand more the bountiful diversity of small mammals across Nigeria. [ABSTRACT FROM AUTHOR]