Abstract
Three new dung beetle species (Onthophagus basilensis Génier sp. nov., O. castus Génier sp. nov., O. larseni Génier sp. nov.) are described from Bioko Island, Equatorial Guinea, and assigned to d’Orbigny’s group IX. Specimens were collected in montane and lowland rainforest using dung-baited pitfall traps. Diagnostic characters, including male genitalia and intraspecific variation, are provided. A review of related taxa indicates that O. denudatus d’Orbigny, 1902 and O. denudatus endroedii Frey, 1973 are distinct, sympatric species separable by external characters and parameral morphology, with no intermediates; Onthophagus endroedii is therefore reinstated as a valid species. These findings highlight the island’s still underexplored Scarabaeinae fauna and emphasize the importance of continued taxonomic surveys and reassessment of species boundaries within the group.
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