During the last two decades, genotyping of African rodents has revealed important hidden diversity within morphologically cryptic genera, such as Rhabdomys. Although the distribution of Rhabdomys is known historically, its diversity has been revealed only recently, and information about the distribution range of its constituent taxa is limited. The present study contributes to clarifying the distribution of Rhabdomys taxa, primarily in southern Africa, and identifies gaps in our knowledge, by: 1) compiling the available information on its distribution; and 2) significantly increasing the number of geo-localised and genotyped specimens (n = 2428) as well as the localities (additional 48 localities) sampled. We present updated distribution maps, including the occurrence and composition of several contact zones. A long-term monitoring of three contact zones revealed their instability, and raises questions as to the role of demography, climate, and interspecific competition on species range limits. Finally, an analysis of external morphological traits suggests that tail length may be a reliable taxonomic trait to distinguish between mesic and arid taxa of Rhabdomys. Tail length variation in Rhabdomys and other rodents has been considered to be an adaptation to climatic (thermoregulation) and/or to habitat (climbing abilities) constraints, which has still to be confirmed in Rhabdomys.
About 200 observations from AD66 to 1910 of the tail length of Comet Halley have been used to derive the mean tail length of the comet as visible to the naked eye under very good observing conditions, The curve, covering an interval of -45-^ (t-T)^ 80 days, is skewed and peaks at -SS million km for (t-T) secular decrease of the tail length.