F. Génier, “Three new species of Onthophagus Latreille, 1802 from Bioko Island, Equatorial Guinea, belonging to d’Orbigny’s group IX, with a taxonomic note on O. denudatus d’Orbigny, 1902 (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini)”, Zootaxa, vol. 5831, no. 3, pp. 413–426, Jun. 2026.