Taxonomy & naming
Gnathonemus marqueti was described in 2026 by Mulelenu, Snoeks, Manda and Vreven, placed in the family Mormyridae — the African weakly electric fishes — within the order Osteoglossiformes, the ancient bonytongue lineage. It was recognised through a morphometric study explicitly framed as 'a first morphometric exploration into a hidden species complex' surrounding Gnathonemus petersii, the elephantnose most familiar to aquarists and long assumed to be a single wide-ranging species across much of Central and West Africa. That study's title and scope indicate G. marqueti is one of several distinct lineages the authors distinguished from material previously identified as G. petersii, though the specific morphological characters used to diagnose it were not accessible for this article.
The genus name Gnathonemus derives from the Greek gnathos ('jaw') and nema ('thread'), referring to the slender, elongate lower jaw shared by many species in the genus. The origin and dedication behind the specific epithet marqueti — whether it honours a person, place or other reference — is not documented in the sources available for this article.
Morphology
No morphometric description specific to Gnathonemus marqueti — body proportions, fin counts, size or colouration — was accessible for this article. As a member of the genus Gnathonemus, it can be expected to share the general elephantnose build: a laterally compressed, deep-bodied trunk, a small terminal mouth, an elongated fleshy 'chin' extension densely packed with electroreceptors, and a slender caudal peduncle housing the electric organ used for electrolocation. Beyond this genus-level expectation, no species-specific measurements are available.
Habitat
Gnathonemus marqueti is known from the upper Kotto River drainage in the Central African Republic, part of the middle Congo River basin. Like other Congo-basin mormyrids, it is likely a demersal freshwater species associated with structurally complex, slow-flowing river habitat, but no specific description of its stream conditions, water chemistry or habitat structure was accessible for this article.
Feeding
No dietary information specific to Gnathonemus marqueti has been published. Gnathonemus and other mormyrids generally forage over sand and soft sediment for small invertebrates such as insect larvae and worms, locating buried prey using the electroreceptor-packed chin appendage together with the fish's electric-organ discharge; whether G. marqueti follows this genus-typical pattern has not been documented.
Mating
No courtship or reproductive behaviour has been documented for Gnathonemus marqueti. In well-studied mormyrid relatives, the electric-organ discharge itself carries information used in species recognition, dominance and courtship interactions, and wild mormyrids are broadly presumed to be seasonal, flood-triggered spawners; neither has been confirmed for this species.
Breeding
No breeding records — wild or captive — exist for Gnathonemus marqueti, which was described only in 2026. Breeding in the genus Gnathonemus as a whole is poorly documented and has rarely, if ever, been achieved in the aquarium, and nothing beyond this general genus-level context can be said for G. marqueti specifically.
In the aquarium
Gnathonemus marqueti is not established in the aquarium trade and, as a fish described only in 2026 from a single Central African river drainage, has no husbandry record. Mormyrids in general are sensitive, largely nocturnal fish that need soft substrate to probe, dim lighting and ample cover, and are typically intolerant of salt, many medications and their own kind; whether any of this applies specifically to G. marqueti has not been tested.
Conservation
Gnathonemus marqueti has not been evaluated by the IUCN Red List, having been described only in 2026. No population, range-extent or threat data specific to the species were accessible for this article beyond its documented occurrence in the upper Kotto River drainage of the Central African Republic; its conservation status is presently unknown rather than assumed secure.