The handsome fellow in the photo above represents a species of the genus Metabiantes, currently the largest recognised African genus of harvestmen in the family Biantidae. Metabiantes species are currently recognised from the greater part of sub-Saharan Africa, with species known from as far north as Kenya on the east coast and the Ivory Coast in the west (Staręga 1992). The bulk of study on this genus, however, has focused on the South African species. Kauri (1961) divided the southern African species between two groups based on genital morphology. Schönhofer (2008) recorded that the widespread Transvaal species M. leighi inhabits leaf litter in evergreen forests. It seems to inhabit slightly drier microhabitats than other harvestmen in the area.
Compared to many other harvestmen, Metabiantes species do not show a high degree of sexual dimorphism. The males' chelicerae tend to be a bit larger, and consequently the front of the carapace tends to be a bit broader (Schönhofer 2008). In some species, the metatarsus of the males' second leg bears a series of teeth (Lawrence 1937). While I haven't found any explicit investigation of the role that such modifications play, the fact that the second legs in harvestmen fill a sensory function (being used much like the antennae in insects) provides a likely suggestion.
Kauri, H. 1961. Opiliones. In: Hanström, B., P. Brinck & G. Rudebeck. South African Animal Life: Results of the Lund University Expedition in 1950–1951 vol. 8 pp. 9–197. Almqvist & Wiksell: Uppsala.
Lawrence, R. F. 1937. The external sexual characters of South African harvest-spiders. Transactions of the Royal Society of South Africa 24 (4): 331–337.
Schönhofer, A. L. 2008. On harvestmen from the Soutpansberg, South Africa, with description of a new species of Monomontia (Arachnida: Opiliones). African Invertebrates 49 (2): 109–126.
Staręga, W. 1992. An annotated check-list of Afrotropical harvestmen, excluding the Phalangiidae (Opiliones). Annals of the Natal Museum 33 (2): 271–336.