Taxonomy & naming
Duringlanis simplex was described by the Dutch ichthyologist Gerlof Fokko Mees in 1974 as Tatia simplex, based on a single juvenile holotype about 1.12 in SL collected from the rio das Mortes, Mato Grosso, Brazil, in 1968. No further material was identified for decades, leaving the species poorly known. A generic revision of the driftwood catfishes in 2008 moved it into Centromochlus, and the Catalog of Fishes now treats Duringlanis simplex as the valid combination, though the original name Tatia simplex still appears in older literature and some database records, including GBIF.
The species belongs to Auchenipteridae, the driftwood or wood catfishes, a South American family distinguished among catfishes by internal fertilisation. Within that family Centromochlus is a genus of small, slender-bodied species often associated with submerged wood and root tangles. The specific epithet simplex is Latin for "simple" or "plain", likely alluding to the fish's unremarkable, lightly marked colouration compared to more boldly patterned relatives.
This fish was long listed as Centromochlus simplex; Eschmeyer's Catalog of Fishes places the species in Duringlanis, and the current combination Duringlanis simplex is followed here.
Morphology
Duringlanis simplex is a small driftwood catfish, reaching only about 1.9 in SL (male/unsexed) at maximum — genuinely tiny by catfish standards and one of the smaller members of its genus. Like other Auchenipteridae it has a slender, laterally compressed body, a blunt head with barbels around the mouth, and a fish that looks unremarkable next to its more ornately patterned Centromochlus relatives, consistent with the "plain" meaning of its epithet.
As in essentially all catfishes the skin is naked and scaleless, which matters directly for medication — see "In the aquarium". Driftwood cats typically carry stiff, serrated pectoral and dorsal spines that can lock erect; handle this species by container rather than net to avoid tangling fine mesh or being jabbed. Detailed morphological description beyond the original juvenile holotype is sparse in the literature, reflecting how rarely the species has been collected or examined since 1974.
Habitat
The species is known only from the rio Tocantins-Araguaia system in central Brazil, specifically the rio das Mortes (the type locality, in Mato Grosso) and the lower rio Tocantins. This is a restricted range even by the standards of small driftwood cats, and available sources describe it as geographically narrow and taxonomically poorly understood.
Specific water chemistry data for this species is not established in the sources reviewed; data is sparse. Driftwood catfishes as a group are generally associated with flowing river habitat and submerged wood, root tangles and leaf litter, which likely applies here given the family's ecology, but precise temperature and pH figures for D. simplex specifically are not documented and should not be assumed.
Feeding
No feeding data specific to Duringlanis simplex was found in the sources reviewed. Related Centromochlus species, such as C. perugiae, are nocturnal benthic omnivores and micro-predators, foraging mainly after dark for small invertebrates and detritus rather than actively hunting by day.
If this pattern holds for D. simplex, as is likely for a small driftwood cat in the same genus, it would be expected to take sinking pellets, frozen foods and small live or frozen invertebrates in the aquarium, offered after lights-out so it is not out-competed by more active tankmates. This should be treated as an inference from its relatives rather than a confirmed fact for the species itself.
Mating
Duringlanis simplex belongs to Auchenipteridae, the family in which nearly all species use internal fertilisation — a genuine rarity among catfishes. In males the anal fin is modified into an intromittent organ, and mating takes place internally rather than through the broadcast release of eggs and milt seen in most catfish families.
Following fertilisation, the female stores sperm and can lay fertile eggs some time later, decoupling mating from spawning in a way almost unique among catfishes. This reproductive mode is documented for the family and genus generally; no species-specific observations of mating behaviour in D. simplex itself were found in the sources reviewed, and given how rarely the species has been collected, direct observation of its reproduction may simply not exist yet.
Breeding
As an auchenipterid, Duringlanis simplex is expected to follow the family's internal-fertilisation strategy: eggs are fertilised inside the female via the male's modified anal fin, and spawning of the stored, fertilised eggs occurs later, with little or no parental care reported afterward in this family. Set against that expectation, there is no documented record of this species being bred in captivity.
Given how poorly known D. simplex is — known from a restricted stretch of the rio Tocantins-Araguaia system and rarely reported since its original 1974 description — it should be treated as essentially unbred and unavailable in the aquarium trade. Anyone encountering fish sold under this name should treat identification with caution, since driftwood cats are frequently mislabelled at the genus or species level.
In the aquarium
Duringlanis simplex is not established in the aquarium trade, and given its restricted range and rarity in collections, is unlikely to be encountered by most keepers. Should it appear, its true small adult size — under 2 in SL — means it does not need a large tank, unlike many driftwood cats whose keepers underestimate eventual size; here the size trap runs the other way, in that a fish sold under a similar name could easily be a larger, look-alike species.
Two care points follow from its biology regardless of exact husbandry specifics: it is a scaleless catfish, so it will be more sensitive than scaled fish to copper and many medications, and dosing should be conservative. It likely carries locking pectoral and dorsal spines typical of driftwood cats, so should be moved by container rather than net. As a probable nocturnal micro-predator, cover such as driftwood and root tangles plus subdued daytime lighting would suit it best, mirroring the wood-associated habitat implied by its family name.
Conservation
The IUCN Red List assesses Duringlanis simplex as Least Concern (2022.2 assessment). This is notable given how narrow its known range is — restricted to the rio das Mortes and lower rio Tocantins within the rio Tocantins-Araguaia system of Brazil — and likely reflects both the absence of known major threats and the general difficulty of assessing a species this poorly collected and studied.
Because the species is known from so few records, its true population status and any local pressures on the Tocantins-Araguaia system, such as damming, agricultural runoff or habitat modification affecting the broader river system, are not well documented for this species specifically. It is not part of the aquarium trade in any meaningful way, so collection pressure is not a relevant concern.