Taxonomy & naming
Petrocephalus pulsivertens was described in 2010 by Sébastien Lavoué, John P. Sullivan and Matthew E. Arnegard, in a revision of the genus Petrocephalus based on fish collected in and around Odzala National Park in the Republic of Congo. The paper, published in Zootaxa (volume 2600, pages 1–52), described five new Petrocephalus species from the Lékoli River system and separated them using a combination of body proportions, fin-ray counts, pigmentation, and electric organ discharge (EOD) waveform. It belongs to the family Mormyridae within Osteoglossiformes, the bonytongue fishes, one of the oldest surviving lineages of teleosts.
The type locality is a small channel around an island in the Lékoli River, within Odzala National Park, at 0.62°N, 14.95°E. The holotype, CUMV 88085, is held at the Cornell University Museum of Vertebrates, with paratypes split between the Cornell collection and the American Museum of Natural History. No synonyms are recorded since the original description, and the Catalog of Fishes lists the name as valid.
Morphology
Petrocephalus pulsivertens is a small mormyrid, with males in the type series reaching about 4.5 in (4.5 in) standard length. The body is ovoid and laterally compressed, 2.6 to 2.9 times longer than it is deep, with a short, rounded snout and a large, subterminal mouth opening beneath the front half of the eye. The eye itself is comparatively large, with a head-length-to-eye-diameter ratio of 3.2 to 3.51. Each jaw carries bicuspid teeth — 15 to 21 in the upper jaw and 24 to 30 in the lower — and the dorsal fin has 25 or more branched rays against 31 or more in the anal fin. Two dark melanin markings, an ovoid patch below the front of the dorsal-fin base and a crescent-shaped mark at the base of the caudal fin, help distinguish this species from the other congeners described alongside it at Odzala.
As in every mormyrid, an electric organ in the caudal peduncle produces a weak pulse discharge used for orientation and communication. In Petrocephalus pulsivertens this discharge is unusual enough to have shaped the species name: the describing authors identified it as the most divergent EOD waveform documented anywhere in the genus, an inverted-polarity version of the typical Petrocephalus pattern. The sequence in which the two electrocyte faces fire is reversed relative to every other known Petrocephalus — the posterior face fires before the anterior face rather than after it — and at high amplifier gain, the very first recordable event in the discharge is a minute head-positive deflection.
Habitat
Petrocephalus pulsivertens is known from the middle Congo River basin in Central Africa, with records from the Lékoli River in Odzala National Park, Republic of Congo, and from Cameroon. The type series was collected from a small channel around an island in the Lékoli River, a benthopelagic freshwater habitat within the Congo basin.
Published water-temperature and pH data specific to this species are not available. Like other Congo basin mormyrids from forest-stream habitat, it can be assumed to live in warm tropical water, but that is a general expectation rather than a measured figure for this population.
Feeding
No dietary study specific to Petrocephalus pulsivertens has been published. Other Petrocephalus species forage on benthic invertebrates — insect larvae, worms, and small crustaceans — located in mud, sand, and leaf litter using their electric sense, and this species is presumed to feed the same way, though that has not been directly documented.
No aquarium feeding record exists for the species, since it has no established presence in the hobby.
Mating
No courtship or mate-recognition behavior has been described for Petrocephalus pulsivertens specifically. In mormyrids generally, the electric organ discharge is thought to carry information relevant to species and individual recognition, and by extension to courtship, alongside its roles in navigation and prey detection. This species' unusually divergent, inverted-polarity discharge would make it an interesting subject for that kind of study, but no such study of pulsivertens has been published.
Age or size at sexual maturity is also unrecorded for this species.
Breeding
No spawning has been recorded for Petrocephalus pulsivertens, in captivity or in the wild. Breeding biology across the genus Petrocephalus, and the family Mormyridae more broadly, remains poorly documented, and this species is no exception — nothing about egg deposition, incubation, or parental care has been published.
The species is not known to be kept or bred in aquaria, so no captive spawning account exists to draw on.
In the aquarium
Petrocephalus pulsivertens has no established presence in the aquarium trade and no documented aquarium-keeping history; it was described in 2010 from a national park research collection, not from trade specimens, and nothing in the literature suggests it has since reached hobbyist tanks. Any care notes for this species are necessarily extrapolated from mormyrids in general rather than drawn from direct experience with it.
Small mormyrids of this kind are generally kept over soft sand for probing, with dim lighting and ample cover, in stable water with minimal turbidity — the group is well known for sensitivity to poor water quality and to some medications, including many common ich and parasite treatments, so cautious dosing and gradual acclimation matter more than with most community fish. Live or frozen invertebrate foods offered after dark suit the natural foraging behavior of the genus better than daytime flake feeding. None of this substitutes for a documented care record specific to Petrocephalus pulsivertens, which does not exist.
Conservation
Petrocephalus pulsivertens has not been evaluated by the IUCN Red List. It was described relatively recently, in 2010, and is known only from a limited set of collections in the middle Congo basin.
No species-specific threats have been documented. As with other freshwater fishes restricted to Congo basin river systems, habitat disturbance and water-quality change in the wider Lékoli drainage are the kind of general long-term pressure that could affect a narrow-range species like this one, though that is a general concern rather than a documented one for Petrocephalus pulsivertens specifically.