Deep in the rainforests of Bioko Island, Equatorial Guinea, a deceptively simple field technique helped reveal beetles that science had never formally recognised. Canadian entomologist François Génier, from the Beaty Centre for Species Discovery at the Canadian Museum of Nature, surveyed the island’s dung beetles using traps baited with animal dung. The unglamorous bait proved remarkably effective. His investigation resulted in the identification and formal description of three previously unknown species of Onthophagus, a diverse genus of dung beetles. The findings, published in Zootaxa in June 2026, also prompted a reassessment of another beetle previously treated as a subspecies. The study demonstrates how much biodiversity can remain hidden even in ecosystems that have been studied for generations. More importantly, it shows why detailed taxonomic work remains essential, before scientists can protect species, they first need to know which species actually exist.
François Génier and the hunt for Bioko’s hidden beetles
Génier is a specialist in dung beetle taxonomy at the Canadian Museum of Nature, where he works at the Beaty Centre for Species Discovery. For his most recent research, Genier chose to examine beetles living in the forests of Bioko Island, which is located near the coast of Equatorial Guinea. For catching the beetles, researchers applied dung-baited pitfall traps, in which they placed animal droppings to attract beetles. This technique may seem too simple, but dung is a highly important thing for many scarab beetles as it provides not only food but also breeding ground for them. Such caught specimens became the basis for Genier’s further taxonomic study. His research ultimately showed that the island’s dung-beetle fauna contained species that had not previously been formally described.
Three new dung beetle species emerge from the rainforest
The study formally describes three new species, Onthophagus basilensis, Onthophagus castus and Onthophagus larseni. In the research paper ‘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,’ Génier assigns all three to d’Orbigny’s group IX. The specimens came from both montane and lowland rainforest, showing that the newly recognised diversity was not restricted to one particular elevation. Identifying the species required more than simply spotting differences in colour or size. Génier examined diagnostic characteristics, including male genital structures and variation within the species. These detailed anatomical comparisons allowed the researcher to distinguish the newly described beetles from closely related species.
Dung-baited traps reveal more than new species
The discoveries also exposed how incomplete scientific knowledge of Bioko’s dung beetles remains. The research did not stop with the three new species. Génier reassessed specimens previously assigned to Onthophagus denudatus and found evidence that O. denudatus endroedii should instead be recognised as a separate species. The researchers found clear differences in external characteristics and the shape of the male genital structures, with no intermediate forms connecting the two. As a result, Onthophagus endroedii was reinstated as a valid species. The finding demonstrates why revisiting museum specimens and established classifications can be just as important as discovering completely unknown animals in the field.
Why three tiny beetles matter to biodiversity science
For his most recent research, Genier chose to examine beetles living in the forests of Bioko Island, which is located near the coast of Equatorial Guinea. For catching the beetles, researchers applied dung-baited pitfall traps, in which they placed animal droppings to attract beetles. This technique may seem too simple, but dung is a highly important thing for many scarab beetles as it provides not only food but also breeding ground for them. Such caught specimens became the basis for Genier’s further taxonomic study. A simple dung trap can therefore become a window into an ecosystem’s hidden diversity. For Génier, the discovery is another reminder that even familiar groups of insects can contain species waiting to be recognised. On a remote African island, animal dung became the unlikely key to uncovering a previously undocumented chapter of beetle biodiversity.
