NON-GEOGRAPHIC VARIATION IN AETHOMYS-CHRYSOPHILUS (DEWINTON, 1897) AND AETHOMYS-NAMAQUENSIS (A-SMITH, 1834) (RODENTIA, MURIDAE) FROM SOUTHERN AFRICA

Prior to a systematic revision of African rock rats (genus Aethomys Th omas) in southern Africa, the nature and extent of non-geographic vari ation due to sex and age in two samples each of A. chrysophilus (De Wi nton, 1897) and A. namaquensis (A. Smith, 1834) were examined using bo th univariate and multivariate statistical procedures. Results of Mode l I two-way analysis of variance, % sum of squares and a series of mul tivariate procedures were congruent and showed a lack of sexual dimorp hism in all samples examined, but marked variation between seven age c ategories based on the degree of tooth wear on the maxillary tooth row . When univariate and multivariate results were considered together, p ooling of sexes as well as individuals of tooth-wear classes IV, V and VI for subsequent recording and analysis was justified. Very few toot h-wear class VII individuals were available and their exclusion was la rgely arbitrary. Few measurements showed sex-age interaction. The larg est per cent contribution to the total variance was due to error. In g eneral, variance partitioning indicated that if comparisons are to be made, caution needs to be exercised on the type of characters, number of factor levels and methodology used.