Allozyme variation and systematics of African mole-rats (Rodentia: Bathyergidae)

Abstract

Patterns of allozyme variation were examined within and among eight taxa representing the five genera of endemic African mole-rats of the family Bathergidae. Populations of Georychus capensis and Cryptomys hottentotus exhibited greater degrees of intraspecific allozyme divergence than did populations of Cryptomys damarensis, Bathyergus suillus, or Heliophobius argenteocinereus. Past climatic cycles may have affected bathyergid genera differentially, resulting in the current differences among taxa in patterns of allozyme variation. Analyses of allozyme variation among genera consistently placed Heterocephalus glaber at the base of the bathyergid radiation. However, allozyme data did not resolve phylogenetic relationships among the remaining four mole-rat genera, suggesting that bathyergid genera may represent lineages of ancient origin. Phylogenetic relationships among genera may be difficult to determine due to the levels of genetic change that have accumulated within each lineage. Allozyme variation among genera, in conjunction with mitochondrial DNA nucleotide sequence data, lead to the conclusion that a revision in the taxonomy of the family Bathyergidae is warranted. We suggest that the naked mole-rat, Heterocephalus glaber, be placed in the subfamily Heterocephalinae, whereas the remaining four bathyergid genera be placed in the subfamily Bathyerginae.