Taxonomy & naming
Pterobunocephalus carvalhoi was described in 2026 by João L. Crispim, Pablo Argüello, Giovanna S. C. Silva, Claudio Oliveira, Kyle R. Luckenbill and Mark H. Sabaj Pérez, in a Neotropical Ichthyology paper titled 'After eight decades: a new species of Pterobunocephalus from the upper Putumayo, Napo and Pastaza rivers, Ecuador.' It belongs to the family Aspredinidae — the banjo catfishes — subfamily Aspredininae, genus Pterobunocephalus.
The genus has a convoluted taxonomic history. Henry Fowler proposed Pterobunocephalus in 1943 as a subgenus of Bunocephalus for a single specimen, Bunocephalus (Pterobunocephalus) albifasciatus; James Böhlke separately erected the monotypic genus Petacara in 1959 for Bunocephalus dolichurus. John P. Friel elevated Pterobunocephalus to full genus status in 1994 and 2003, treating Petacara as a junior synonym and recognizing two valid species, P. depressus and P. dolichurus, with albifasciatus folded in as a synonym of depressus. P. carvalhoi is the third species recognized in the genus since that revision — the first addition in over eighty years.
Some of the type material had actually been collected decades earlier: four specimens gathered by Wilbur Saul near Santa Cecília, Ecuador, in the 1960s were originally identified as Bunocephalus aleuropsis and catalogued as such in his own 1975 ecological survey. Re-examination for this description showed they belong instead to the new species. The holotype, MEPN-I 20199 (2.75 in SL), was collected from an unnamed river near the Sani Isla North oil well platform in the headwaters of the Pañayacu River, Napo basin, Ecuador. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) records Pterobunocephalus carvalhoi Crispim, Argüello, Silva, Oliveira, Luckenbill & Sabaj Pérez, 2026 as the valid name.
Morphology
Pterobunocephalus carvalhoi has the depressed, wide head and slender tapering body typical of banjo catfishes. It is diagnosed from its two congeners chiefly by unusually large eyes — 11.2–13.9% of head length, versus 6.0–9.1% in P. depressus and P. dolichurus — and by the shape of the anterior snout margin, where the mesethmoid bone sits sunken behind the premaxillae rather than level with them. It also carries fewer anal-fin rays (10–11) than P. dolichurus (15–16), and the parapophysis of the fifth vertebra is narrow at its base and flares abruptly outward at the tip into a blade shape the authors compare to a shepherd's axe — a feature shared with P. depressus but not with P. dolichurus.
Across the type series, standard length ranges from about 1.17 in to 2.93 in, with the holotype at 2.75 in — giving a described maximum of roughly 2.9 in SL. The skull carries three raised bony protuberances along the midline, all three barbel pairs are simple (unbranched), and the skin is covered in small tubercles arranged in longitudinal rows, more pronounced on the caudal peduncle. The pectoral spine bears 13–15 serrations along its front edge and 9–12 along the back, increasing in number as fish grow. In preserved specimens the body is brown to beige above and pale below, with a dark saddle centered on the dorsal fin and further faint saddles toward the tail; the head is mottled with dark blotches, and the pelvic, anal and caudal fins carry scattered brown spots on a translucent ground.
Habitat
Pterobunocephalus carvalhoi is known from six localities across three river basins in the Ecuadorian Amazon — the Napo (including its Rumiyacu and Jivino tributaries), the Pastaza (via the Bobonaza River), and the Putumayo (via the Blanco/Conejo River, which links to the Napo system during high water). At the Conejo River locality, the channel runs about 20 ft wide beneath overhanging riparian vegetation, with water color shifting from yellow-brown in the wet season to olive or tea-colored in the dry season; water temperature was recorded at about 73 °F, pH about 6.5, and dissolved oxygen about 6.5 ppm during 1960s sampling. Paratypes there were collected specifically from the swift channel over solid sand, clay and bedrock, while material from the Jivino River, a Napo tributary, came from a similarly densely vegetated stretch.
Feeding
Gut contents recorded for the Conejo River population — now recognized as belonging to this species — showed a diet of insects, plant debris and chironomid (non-biting midge) fly larvae, gathered along the swift, sandy-to-rocky river channel. No feeding observations have been published for the other populations.
Mating
No courtship behavior has been recorded for Pterobunocephalus carvalhoi. The genus-level Aspredinidae diagnosis compiled by Friel in 1994 lists females bearing embryos directly attached to the body as a defining trait of Pterobunocephalus, but the authors of the 2026 description explicitly note that it is not known whether females of this particular species carry embryos in that way — the trait is documented in other genera of the family but unconfirmed here.
Breeding
Breeding biology is undocumented for Pterobunocephalus carvalhoi specifically. If it follows the pattern reported for the wider genus, fertilized eggs may be carried attached to the female's skin, but this has not been observed or confirmed for this species, and it has never been bred in captivity.
In the aquarium
Pterobunocephalus carvalhoi is not in the aquarium trade; described only in 2026 from 15 known specimens, it has no husbandry record. Any care guidance is genus-level speculation: other banjo catfishes in Aspredinidae are peaceful, nocturnal, sand-dwelling bottom fish that do well with soft substrate, leaf litter and driftwood cover, and their naked, scaleless skin makes them more sensitive than average to copper-based medications. None of this has been confirmed for P. carvalhoi.
Conservation
Pterobunocephalus carvalhoi has not been formally assessed by the IUCN Red List. The describing authors recommend a preliminary Least Concern classification despite only 15 known specimens, noting that Aspredinidae as a family is generally under-recorded in scientific collections because its members are difficult to collect; the species' documented range already spans three separate hydrographic basins (Napo, Pastaza and Putumayo) in the upper Amazon, suggesting it is not confined to a single small area. This is the authors' own preliminary recommendation, not a formal IUCN listing.