Taxonomy & naming
Neoplecostomus doceensis was described by Roxo, Silva, Zawadzki, and Oliveira in 2014 in ZooKeys (volume 440, pages 115–127, DOI: 10.3897/zookeys.440.8203). The type locality is Córrego Bananeiras, an affluent of Rio Gualaxo do Norte in the Rio Doce basin, in the municipality of Ouro Preto, Minas Gerais State, Brazil (20°14'20"S, 43°28'40"W). The Catalog of Fishes (Eschmeyer, CAS) recognises Neoplecostomus doceensis Roxo, Silva, Zawadzki & Oliveira, 2014 as the valid name.
The genus Neoplecostomus belongs to the subfamily Neoplecostominae — a clade of predominantly Southeastern Brazilian loricariids adapted to fast, rocky streams of the Atlantic and interior drainages. The 2014 paper also discusses the putative biogeographic origin of the species within the Rio Doce system, which is notable for its high degree of endemism among freshwater fishes.
Morphology
Adults reach up to 4 in standard length (SL). Key morphological features noted in the original description include enlarged fleshy folds between the dentaries — a character that is more prominent in mature males — and two or three series of well-developed papillae anterior to the premaxillary teeth. The species has a fully developed adipose fin, a well-developed dorsal-fin spinelet, and 25–29 lateral-line plates.
The body plan is typical of neoplecostomines: streamlined, dorsoventrally flattened, with the underside bearing the characteristic suckermouth. The enlarged fleshy dermal folds around the mouth represent the most diagnostic soft-tissue character separating N. doceensis from congeners. General coloration is not described in detail in the available literature for live specimens.
Habitat
Neoplecostomus doceensis is endemic to the Rio Doce basin of Minas Gerais, southeastern Brazil. It was recorded from thirteen collection localities across the basin, spanning the rios Gualaxo do Norte, Gualaxo do Sul, José Pedro, Piranga, Manhuaçu, Suaçuí Pequeno, and the Xopotó system (five sites). The Rio Doce drainage covers approximately 83,249 mi² and is one of the major river systems of the Atlantic Forest biome.
The species inhabits clear-water rivers of small to medium size, characterised by rocky outcrops forming small waterfalls and rapids, with substrates of rocks and sand. This rheophilic microhabitat — fast flow over hard substrate — is the defining environment of Neoplecostomus throughout its range. The high oxygen demand of these fish means that flowing, well-aerated water is an ecological requirement rather than a preference.
Feeding
No gut-content analyses for N. doceensis are published in the available literature. Based on the suckermouth morphology, rheophilic habitat, and feeding ecology of congeneric and closely related neoplecostomines, the species is inferred to be a scraper of periphyton, algae, and associated biofilm from rock surfaces in fast-flowing sections of its home streams. This is the predominant feeding mode across Neoplecostomus and related genera in Southeastern Brazilian highland drainages.
Mating
Courtship behaviour has not been described for Neoplecostomus doceensis. The prominence of the enlarged fleshy dentary folds in mature males (compared to females) suggests these structures may play a role in intrasexual competition or mate assessment, as is the case for analogous secondary sexual characters in other loricariid groups, but this remains speculative in the absence of behavioural data.
Breeding
Reproductive biology of N. doceensis is undescribed. The species is not known from aquarium culture, and no breeding reports exist. Reproductive mode can only be inferred from the broader loricariid context: neoplecostomines are generally expected to be substrate spawners in rheophilic habitats, but the specific clutch size, incubation period, and parental-care behaviour for this species are unknown.
In the aquarium
Neoplecostomus doceensis has not been established in the ornamental fish trade, and no aquarium-husbandry data exist. As a rheophilic specialist from clear, swift, rocky streams in a restricted endemic range, it would demand high water flow, excellent oxygenation, low organic loading, and hard rocky substrate replicating its natural environment. Specific water-chemistry parameters for captive maintenance are not available. The species should be considered absent from commerce for the foreseeable future.
Conservation
Neoplecostomus doceensis has not been evaluated by the IUCN Red List (status: Not Evaluated). The species was described in 2014 from thirteen localities distributed across multiple tributaries of the Rio Doce — a broad enough distribution within the basin to suggest it is not extraordinarily rare at the time of description.
However, the Rio Doce suffered a catastrophic environmental event in November 2015, when the Fundão tailings dam operated by Samarco (Vale/BHP joint venture) collapsed near Mariana, Minas Gerais. The collapse released approximately 43 million cubic metres of iron ore tailings into the drainage, creating a toxic plume that travelled the full length of the Rio Doce — over 404 mi — before reaching the Atlantic Ocean. Documented impacts included mass fish mortality, smothering of benthic substrates, and destruction of riparian and aquatic ecosystems across a vast portion of the catchment.
Several of the thirteen localities where N. doceensis was collected — including sites in the Gualaxo do Norte and Gualaxo do Sul systems, which are in the primary impact zone of the Fundão dam — were likely directly affected by the 2015 plume. The full extent of population-level impacts on this species has not been assessed, and no post-disaster survey results specific to N. doceensis are available in the published literature. An IUCN evaluation accounting for the Fundão disaster and its ongoing ecological legacy would be scientifically warranted.