Taxonomy & naming
Sternarchorhynchus taphorni was described by de Santana and Vari in 2010 and placed in the family Apteronotidae, the ghost knifefishes, within the order Gymnotiformes — the New-World electric knifefishes. These are bony fish, but unusual ones: the Gymnotiformes are defined by an electric organ and a single long ribbon-like anal fin used for propulsion, and they are only distantly related to the more familiar aquarium fish groups. The Apteronotidae are distinguished within the order by an electric organ built from modified nerve cells rather than muscle tissue, which produces the fastest, steadiest wave-type discharges of any knifefish family.
The genus Sternarchorhynchus — its name built from the Greek sternon (chest), archo (rule, or 'first'), and rhynchus (snout) — comprises the tube-snouted ghost knifefishes, a large and still-growing genus of more than thirty described species, roughly two-thirds of them restricted to the Amazon basin. The species epithet taphorni is a patronym honouring Donald Taphorn, an ichthyologist noted for his work on Venezuelan freshwater fishes. Despite the shared common name 'knifefish', Sternarchorhynchus and its Apteronotidae relatives are not related to the Asian featherback and clown knifefishes (Chitala, Notopterus); the resemblance in body shape is convergent, not a sign of kinship. The Catalog of Fishes (Eschmeyer, CAS) is the authority for the valid name.
Morphology
Sternarchorhynchus taphorni reaches about 12 in in total length, modest for the family but typical of the genus. Like other tube-snouted ghost knifefishes, it has an elongated, tubular, somewhat downturned snout — the feature that gives the genus its common name and that concentrates electroreceptors for probing into crevices and substrate. The body is slender and laterally compressed, tapering toward the tail, with no dorsal fin and no distinct tail fin; forward and backward movement instead comes from a long anal fin run as a travelling wave along the underside of the body, the signature Gymnotiform swimming style.
As in all Apteronotidae, the electric organ runs along the body and generates a continuous, high-frequency wave-type discharge — in this family produced in the 400–2,000+ Hz range — read by an array of electroreceptor pores across the skin. The species is scaleless, like every gymnotiform, which leaves the skin exposed and shapes how it must be handled and medicated in any captive setting. Detailed morphometric and coloration data for S. taphorni specifically are not well documented outside the original description; the genus in general is drab — grey to brownish — rather than patterned.
Habitat
Sternarchorhynchus taphorni is known from Peru, part of the wider Amazon basin distribution typical of its genus, in which roughly two-thirds of the recognised species are restricted to Amazonian drainages spanning Bolivia, Brazil, Colombia, Ecuador and Peru. The specific river system and type locality for S. taphorni are not established in general reference sources and would require consulting the original 2010 description.
Members of the genus Sternarchorhynchus are typically fish of well-oxygenated waters — deep river channels, rapids, pools at the base of waterfalls, and in some cases even subterranean cave waters — rather than still, stagnant habitats. This is consistent with the deep-channel, current-loving habits reported across the tube-snouted ghost knifefishes generally. Specific temperature and pH data for S. taphorni are not available; a related congener, S. oxyrhynchus, has been documented in water around pH 6.2–7.2 and 75–82 °F, figures that are indicative of the genus's general preference for warm, near-neutral to slightly acidic water rather than confirmed for this species.
Feeding
As an apteronotid, Sternarchorhynchus taphorni is presumed to be a nocturnal carnivore that hunts using electrolocation, detecting small invertebrates hidden in sediment or wedged into crevices and channel-bed cover, much as its better-studied relatives do. The genus's elongated, tubular snout is thought to be an adaptation for probing into narrow spaces — root tangles, rock crevices, and the interstitial spaces of coarse substrate — for buried or hidden prey, a feeding strategy distinct from the blunter-snouted ghost knifefishes like Apteronotus.
No species-specific dietary study for S. taphorni is available in general sources; this account follows the well-documented feeding ecology of the wider Apteronotidae rather than direct observation of this species. Data sparse.
Mating
Courtship and spawning behaviour in Sternarchorhynchus taphorni have not been documented. Across Apteronotidae, however, the electric organ discharge is known to function as a social and reproductive signal as well as a sensing tool: in the best-studied relative, the brown ghost knifefish (Apteronotus leptorhynchus), males and females shift their discharge frequency during courtship in an electrical 'duet', and the waveform and frequency of the discharge convey sex, size, species identity and social status. It is reasonable to expect broadly similar electric signalling in courtship across the family, including in Sternarchorhynchus, but this has not been specifically studied or confirmed for S. taphorni.
Data sparse for this species; no field or captive observations of pairing or spawning behaviour are available in general reference sources.
Breeding
There is no documented account of Sternarchorhynchus taphorni breeding in captivity, and it is not established in the aquarium trade at all. Apteronotidae in general are egg-scattering fish producing adhesive eggs among cover, with no substantial parental care once spawning is complete — in the rare cases where family members have bred in captivity (mostly other genera, such as Apteronotus), reproduction has depended on large, mature, well-conditioned fish in soft, warm water, and commercial supply of related species has mostly relied on wild capture or hormone-induced breeding on fish farms rather than natural spawning in captivity.
For S. taphorni specifically, breeding mode and any parental care are unrecorded. Rarely bred, poorly documented — no protocol should be assumed or attempted based on this account.
In the aquarium
Sternarchorhynchus taphorni is not a fish found in the aquarium trade. Like most of its genus, it is a deep-channel, current-loving fish of Amazonian rivers that is essentially unavailable to hobbyists and is known almost entirely from scientific collection and description rather than the ornamental supply chain. The general husbandry principles that apply to gymnotiforms would apply to it in the unlikely event it were kept: as a scaleless fish it would need great care with medications — no copper-based treatments, and reduced doses of anything else — along with excellent water quality, since scaleless skin is unusually sensitive to ammonia and nitrate.
As a nocturnal, electrolocating predator, it would need a dim, well-covered tank and would not be safe with small, bite-size tankmates. Its long, probing snout and deep-channel habits suggest it would also want strong water flow and oxygenation rather than the still water many community tanks provide. None of this is drawn from direct husbandry experience with the species, since none appears to exist; it is a scientific fish, not a hobby one.
Conservation
Sternarchorhynchus taphorni is assessed by the IUCN as Least Concern, assessed 2014-04-24, based on FishBase's record of the assessment. As with many gymnotiforms, this reflects the fact that the species has not been flagged as facing acute pressure rather than a wide, well-mapped distribution — the genus includes many narrow-range, single-basin endemics for which the greater long-term risks are the general threats to Amazonian rivers: deforestation, damming, mining-related pollution and mercury contamination, and broader habitat change in Peru's river systems.
As a fish essentially absent from the aquarium trade, S. taphorni faces no meaningful collection pressure from the hobby; its conservation outlook depends entirely on the health of the Peruvian Amazonian waters it inhabits.