Taxonomy & naming
Pseudobunocephalus lundbergi was described by John P. Friel in 2008 from Caño Barranca, a tributary of the río Caura in Bolívar, Venezuela. The description simultaneously erected the genus Pseudobunocephalus to house this species and its close relative, splitting them out from the older, broader banjo catfish genus Bunocephalus on the basis of skeletal and other morphological differences. The family is Aspredinidae, the banjo catfishes, within the order Siluriformes. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) treats Pseudobunocephalus lundbergi as the currently valid name, and older literature or trade references to this fish under Bunocephalus should be read as the pre-2008 combination.
The genus name Pseudobunocephalus is built from the Greek pseudo- ("false") prefixed to Bunocephalus, the older banjo-cat genus it was split from — literally "false Bunocephalus", flagging the genus as a lookalike but distinct lineage. The species epithet lundbergi honours ichthyologist John G. Lundberg, a leading authority on catfish systematics, in recognition of his contributions to Siluriformes taxonomy.
Morphology
Like all banjo catfishes, Pseudobunocephalus lundbergi has the family's signature shape: a broad, flattened, disc-like head and forebody tapering to a slender, almost rat-like tail, giving the fish its "banjo" silhouette. The body is naked — entirely without scales — and instead covered in small bony platelets and tubercles typical of the family, camouflaged in mottled brown and cream tones that blend into sand and leaf debris.
The species is exceptionally small: the holotype measures 1 in standard length, and specimens in the genus generally run 1 in SL, with all species in Pseudobunocephalus staying under 3 in SL. This places Pseudobunocephalus lundbergi among the smallest catfishes kept in the hobby at all — smaller than most tetras. Because the skin is scaleless, it shares the medication sensitivity common to naked-skinned catfishes, loaches, puffers and eels; treatments (especially copper-based ones) should be dosed conservatively, often at half strength.
Habitat
The species is native to the Orinoco River basin of Venezuela and Colombia, known from the lower río Caura, the upper río Apure and the río Meta. The type locality is Caño Barranca in the río Caura drainage, Bolívar, Venezuela (7°08'N 65°04'W). It is recorded from relatively few localities, but the describing sources note it is likely more widely distributed across the Orinoco drainage than current records show.
Pseudobunocephalus lundbergi is a freshwater, benthopelagic fish that favours small rivers shaded by marginal vegetation, sheltering amid aquatic plants and accumulated leaf litter on the substrate. This leaf-litter, blackwater-adjacent habitat gives the fish both cover from predators and a substrate that matches its cryptic colouration.
Feeding
As a small, bottom-dwelling banjo catfish, Pseudobunocephalus lundbergi is best understood as a nocturnal benthic micro-predator, foraging over sand and leaf litter after dark for tiny invertebrates and detritus rather than actively chasing prey in open water. Its diminutive size means prey items are correspondingly small — worms, small crustaceans and aquatic insect larvae are the likely wild diet, consistent with the diet of related banjo catfishes.
In the aquarium, this feeding style translates into a need for sinking foods offered after lights-out: small frozen fare such as baby brine shrimp and bloodworm, along with sinking micro-pellets, are appropriate given its tiny mouth and body size. Because it forages by night and is easily outcompeted by more active tankmates, feeding should target the substrate once the lights are off.
Mating
Specific courtship and spawning behaviour for Pseudobunocephalus lundbergi has not been documented; data is sparse for this recently described, seldom-studied species. What is known comes from the broader biology of Aspredinidae, the banjo catfish family, in which several species show an unusual reproductive strategy: rather than laying eggs freely or building a nest, the female carries the fertilised eggs attached to her belly skin via short fleshy stalks (cotylophores) until they hatch. In banjo catfishes generally, clutch sizes documented for related species can run into the thousands of eggs.
Whether Pseudobunocephalus lundbergi follows this egg-carrying pattern specifically has not been confirmed in the available literature, and courtship behaviour leading up to spawning is undescribed for the genus.
Breeding
Breeding of Pseudobunocephalus lundbergi is essentially undocumented, and this should be stated plainly rather than guessed at. Aspredinidae as a family includes species where the female carries adhesive eggs on her belly until they hatch, a strategy quite unlike the free-spawning or nest-building habits of most other catfish families, but confirmation of this specific mode in P. lundbergi is lacking.
Captive breeding of banjo catfishes in general is extremely rare and essentially undocumented for most species, including this one. There are no known aquarium spawning reports for Pseudobunocephalus lundbergi; hobbyists should not expect to breed this species, and any fish in the trade should be assumed wild-collected.
In the aquarium
Pseudobunocephalus lundbergi is a genuinely tiny catfish — adults top out around 1 in — so tank sizing is about providing a calm, well-covered environment rather than accommodating growth; this is one of the rare catfishes where the usual "size trap" runs in reverse; do not expect it to need a large tank, but do not house it with anything that could see it as a snack, either. A soft substrate of sand, leaf litter and driftwood mimics its native leaf-shaded river habitat and gives this shy, nocturnal fish the cover it needs to feel secure during the day.
Because it is scaleless, medications — copper treatments in particular — should be dosed conservatively, ideally at reduced strength, exactly as with loaches, puffers and other naked-skinned catfishes. Its minute size also means it should only be combined with very small, peaceful tankmates; anything large enough to eat a 1 in fish is unsuitable. As a nocturnal forager it appreciates dim lighting and feeding after dark, and given how little is known about its captive requirements, keepers should treat it as a specialist fish for experienced aquarists rather than a beginner catfish.
Conservation
The IUCN Red List assesses Pseudobunocephalus lundbergi as Least Concern, in an assessment dated October 7, 2020. The species is known from relatively few recorded localities within the Orinoco basin, but assessors note it is likely more widely distributed across the drainage than current records reflect, supporting the Least Concern status despite the limited number of confirmed sites.
As with many small, poorly surveyed Orinoco basin fishes, ongoing habitat pressures in the region — including deforestation and water-quality changes affecting the shaded small-river habitats it depends on — are the type of long-term concern relevant to species like this, even though it is not currently classified as threatened.