Costabolus gen. nov.

Type species: Costabolus baculus sp. nov., by present designation.

Name. Reflecting the longitudinal costae/ribs on the metazonae, and ʻ-bolusʼ, a common suffix for genus-group names in the Spirobolida; masculine in gender.

Diagnosis. Distinguished from all pachybolid genera but Carinobolus gen. nov. by strongly crested metazonae, from Carinobolu s gen. nov. by the crests being simple, even, not bimodal, by the presence of prominent prefemoral protuberances on male legs 2 and of prominent coxal protuberances on male legs 3, and the anterior gonopods being subtriangular in overall shape, vs. rather palm-shaped in Carinobolu s gen. nov. See also Key below.

Distribution. Only known from the type locality in southeastern Nigeria (Fig. 8).