Allometric growth, handedness, and morphological variation in Potamonauteswarreni (Calman, 1918) (Decapoda, Brachyura, Potamonautidae) with a redescription of the species

Some morphological relationships are investigated amongst three populations of Potamonautes warreni (Calman, 1918) and the species is redescribed. Dif ferences between sexes as well as the growth of the carapace, chelipeds, an d handedness are quantified. Sex ratios did not differ significantly from 1 :1 among sites, and no differences in the carapace variables were evident b etween sexes. Both sexes were heterochelous, with the right chela usually b eing larger in males than in females. Sexual dimorphism is evident for the width of the abdominal somites. The functional significance of an enlarged right chela, and that of patterns of allometric growth are discussed. In ad dition, the structure of pleopod 1, mandibular palp, chelipeds, and the thi rd maxilliped are described and illustrated. The distribution of P. warreni is re-examined and the species appears to be restricted to the Orange Rive r System and its major tributaries such as the Vaal River in South Africa a nd Namibia.