Taxonomy & naming
Mormyrops tubirostris was described by the Belgian-British ichthyologist George Albert Boulenger in 1900 from material collected on the Gambia River in West Africa by the naturalist John Samuel Budgett. Boulenger placed it in the genus Mormyrops, in the family Mormyridae — the mormyrids, or elephantfishes — within the order Osteoglossiformes, the bonytongues. Bonytongues are named for a toothed bone on the floor of the mouth that bites against a matching tooth plate on the roof, and the order is one of the oldest surviving lineages of bony fish, with representatives scattered across South America, Africa, Southeast Asia and Australasia.
The Catalog of Fishes (Eschmeyer, California Academy of Sciences), the standing authority for valid fish names, currently treats Mormyrops tubirostris Boulenger, 1900 as a junior synonym of Mormyrops boulengeri Pellegrin, 1900. In practice this means the population Boulenger described from the Gambia River is now regarded as the same species as boulengeri, and most of what is recorded about its biology — including the range given below — is filed under the boulengeri name. Whether that reflects one genuinely wide-ranging species spanning West and Central Africa, or an old lumping of two geographically separate populations, is not resolved in the sources consulted here.
The genus name Mormyrops combines Mormyrus, an older mormyrid genus name, with the Greek ops, meaning face or appearance — roughly "Mormyrus-like". The species epithet tubirostris is built from the Latin tubus (tube) and rostrum (snout or beak), describing the fish's elongated, tube-shaped snout.
Morphology
Mormyrops is a genus of elongate, thick-bodied mormyrids with a single, rear-set dorsal fin, a deeply forked tail on a narrow caudal peduncle, and no adipose fin — the standard mormyrid body plan. Unlike the trunk-nosed elephantnoses of the genus Gnathonemus, Mormyrops species do not carry a fleshy chin appendage; the snout is simply drawn out, and in this species notably elongated and tapered, which is what the epithet tubirostris describes.
Reported maximum size, recorded under the current name Mormyrops boulengeri, is about 9.8 in total length. That makes it a modest species within a genus that also holds much larger predatory mormyrids — Mormyrops anguilloides can exceed a metre — so tubirostris is not in that size class. As in all mormyrids, an electric organ built from modified muscle tissue sits in the caudal peduncle and produces a weak, species-specific pulse-type electric organ discharge, typically under one volt, used for electrolocation and communication rather than for stunning prey or defence.
Mormyrids as a family are known for having among the largest brain-to-body mass ratios of any fish, with an enlarged cerebellum devoted to processing the constant stream of electrosensory information from that discharge. That trait has not been studied specifically in tubirostris or boulengeri, but it is a defining feature of the family the species belongs to.
Habitat
As currently understood under the synonymy with Mormyrops boulengeri, the species is documented from the Congo River basin, with records from the Alima River, Pool Malebo (Stanley Pool), Lake Tumba, the Ruki River and the Itimbiri River, spanning the Democratic Republic of the Congo and the Republic of the Congo. It is a demersal, tropical freshwater fish, living near the bottom rather than in open water.
Water temperatures across these records run about 73–79 °F. Congo basin rivers and floodplain lakes of this kind are typically soft and often tannin-stained, running from slightly acidic toward neutral — the dim, low-visibility water an electric sense is well suited to reading — though the sources available here do not report a measured pH for this species specifically. The original Gambia River type locality lies far to the west, in a separate river system, which is the geographic mismatch behind the synonymy note above.
Feeding
Feeding habits have not been documented specifically for Mormyrops tubirostris, but the genus as a whole forages over the bottom for aquatic invertebrates — insect larvae, worms, small crustaceans and other benthic prey — located mostly by electrolocation and touch rather than sight, in the dark or turbid water mormyrids typically inhabit. Most mormyrids are more active after dark, when the electric sense gives them an advantage over fish that hunt by sight.
Larger Mormyrops species are known to take small fish as well as invertebrates, but nothing in the sources reviewed here documents diet specifically for this species; anything more precise would be guesswork.
Mating
Mating behaviour in Mormyrops tubirostris is not documented in the sources available here, and reproduction across the mormyrid family generally is poorly studied. What is known from related mormyrids points to seasonal, flood-triggered spawning tied to the rise of river levels, when turbid, food-rich floodplain water opens new spawning and nursery habitat.
The electric organ discharge is thought to play a role in courtship and species recognition in mormyrids generally, letting a fish identify a same-species mate by the shape of its pulse before contact is made, but the details of any courtship display in this species are not described in the sources consulted.
Breeding
Breeding in Mormyrops tubirostris, or under its current name M. boulengeri, is essentially undocumented. Mormyrids as a family are seasonal spawners tied to seasonal flooding, and some are thought to scatter eggs among flooded vegetation or guard them briefly, but reliable observations are scarce even for well-studied genera, and none of the sources reviewed here report breeding data for this species.
Aquarium breeding of mormyrids in general is rare to the point of being essentially unachieved, and this species has no aquarium history to draw on at all. Anyone encountering wild-collected stock should treat reproduction as unstudied territory rather than expect a known protocol.
In the aquarium
Mormyrops tubirostris — M. boulengeri under the current name — has no established presence in the aquarium hobby. It is not a trade species, and none of the sources reviewed here describe aquarium care specific to it; anything below is drawn from the general care needs of Mormyridae rather than from experience with this fish.
Mormyrids in general do best in soft, dimly lit water with a low to neutral pH, plenty of cover such as roots and wood, and a sand substrate they can probe with their electric sense; sudden bright light and reflective surfaces can distress them. Water quality has to stay clean and stable — mormyrids are notably sensitive to poor water and to many medications, particularly anything containing copper, so doses should be conservative. Many species, including several other Mormyrops, are territorial and can be aggressive toward their own kind, so keeping more than one together needs care and usually a large tank.
None of this has been tested specifically on Mormyrops tubirostris. Given the size and temperament seen elsewhere in the genus, and the total absence of trade or hobbyist reports, this is not a species to plan a tank around without direct, current information from whoever is offering it.
Conservation
The IUCN Red List records the taxon as Least Concern, an assessment made in 2009 under the current name Mormyrops boulengeri. It is documented from multiple river systems and a large lake within the Congo basin, consistent with a species that is not narrowly range-restricted at the scale the assessment covers.
That assessment is now well over a decade old, and the Congo basin faces ongoing pressure from deforestation, sedimentation and localized overfishing that affects many of its fish communities. None of the sources reviewed here report a species-specific reassessment or population trend for tubirostris or boulengeri since 2009.