Costabolus gen. nov.

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

No other species known.

Diagnosis. A tribe of the family Pachybolidae characterized by the following putative apomorphies or synapomorphies:

- incisura lateralis closed (Figs 2B, 5D), a synapomorphy shared with Pachybolini (Wesener et al. 2008);

- setae on lamellae linguales apical (Figs 2D, 5H), a synapomorphy shared with Pachybolini (Wesener et al. 2008);

- vulva subreniform and bivalve (Fig. 7A, B), a synapomorphy shared with Pachybolini (Wesener et al. 2008), but devoid of a central ridge, this being an apparent plesiomorphy.

- both posterior gonopods mostly connected by a tiny sternite, each distinctly biarticulate near midlength (Figs 3G–I, 6J–K), telopodite clearly twisted based on a subtransverse course of the seminal groove dividing the coxite and telopodite.