Abstract
Specimens belonging to the genus Leiodontocercus are rare or even absent in natural history museum collections; this is likely due to at least two reasons, notably, their relatively small size, and, the sheer difficulty in finding them in dense Afrotropical forests. Until recently, three species from less than fifteen specimens were known from this genus, whose identification relied on a singular diagnostic character, that is, the shape of the male cerci. The present contribution is based on the examination of thirty specimens collected from various countries, ranging from central to west Africa; apart from the male cerci, a second diagnostic character - the stridulatory file - is used to distinguish species, even though it is difficult to examine in mounted specimens. As a result, four new species were detected, namely, L. vicii sp. nov., L. spinicercatus sp. nov. (from the Central African Republic), L. muticus sp. nov. (from Gabon and Cameroon) and L. philipporum sp. nov. (from Côte d'Ivoire). Moreover, L. condylus is recorded from the Central African Republic, the only country where three species of this genus co-occur. It is suggested that population isolation during fluctuating humid and dry periods, consequent to the influence of Ice Age impact during the Pleistocene in tropical central Africa, is the best explanation for the adaptive radiation of the group.