Comparative renal morphology of some southern African otomyine rodents

Abstract

The kidney structure of 21 individual otomyine rodents representing six southern African taxa from localities with differing climatic profiles was studied by means of light microscopy. Variation in the data was accounted for primarily by relative cortex and medulla proportions. The kidneys of Otomys angoniensis Wroughton, 1906, O. irroratus (Brants, 1827) and O. sloggetti robertsi Hewitt, 1927 displayed mesic adaptation, and those of O. unisulcatus F. Cuvier, 1829, Parotomys brantsii (A. Smith, 1834) and P. littledalei Thomas, 1918 xeric adaptation, reflecting species-specific patterns of geographic distribution across southern African rainfall gradients. Neither mesic nor xeric renal characters appear optimally expressed in the species considered, and it is postulated that feeding habits and behavioural adaptations play a significant role in the water economy of otomyine rodents.