Taxonomy & naming
Lamontichthys avacanoeiro was described by de Carvalho Paixão and Toledo-Piza in 2009 in Neotropical Ichthyology (volume 7, number 4, pages 519–568). The Catalog of Fishes (Eschmeyer, CAS) recognises the species as valid. It belongs to the subfamily Loricariinae, the whiptail and twig-catfish lineage of the Loricariidae, and within that group to the genus Lamontichthys — a small assemblage of rheophilic, sturisomatine-type loricariines adapted to fast, clear-flowing water.
The describing authors distinguished L. avacanoeiro from its congeners by a shorter first branched dorsal-fin ray in specimens larger than 3 in standard length (22.6–26.0% of SL versus 26.4–40.5% in related species), by an oval plateless area at the snout tip, and by teeth bearing long cusps. The genus name honours the ichthyologist Francesca Raimonde La Monte of the American Museum of Natural History; the species epithet honours the Avá-Canoeiro indigenous people of the upper Tocantins region, near which the type material was collected.
Morphology
Lamontichthys avacanoeiro reaches about 6.5 in standard length. The body is markedly elongated and depressed, the characteristic whiptail form of the Loricariinae, encased in the overlapping bony plates typical of the family. The snout is long, with an oval plateless area at its tip — one of the diagnostic features the describers used to separate the species. The teeth bear long cusps.
The most useful diagnostic proportion is the length of the first branched dorsal-fin ray, which is comparatively short in adults of this species (22.6–26.0% of standard length in specimens over 3 in). Beyond these published characters, detailed accounts of coloration and fine external morphology are sparse, and no sexual dimorphism has been documented for the species.
Habitat
The species is endemic to the upper rio Tocantins basin in Goiás, central Brazil, where it occupies freshwater, demersal, tropical habitat. Lamontichthys as a genus is rheophilic — adapted to fast, clear, well-oxygenated current — and the elongated, plated body of L. avacanoeiro is consistent with life pressed against substrate in flowing water.
Specific published data on water temperature, pH, hardness, and depth at the collection sites are not available in the sources to hand. What is clear is that the distribution is narrow and confined to a single river system, a fact that bears directly on the species' conservation status.
Feeding
No diet has been published for Lamontichthys avacanoeiro. Loricariines of this body form are generally substrate-associated grazers and detritivores, feeding on biofilm, algae, and fine organic material rasped from rocks and wood in flowing water, but in the absence of stomach-content or field-feeding data for this species any specific account would be speculation. Treat its feeding ecology as unrecorded.
Mating
No courtship or mating behaviour has been described for this species. Nothing reliable can be said about its reproductive interactions from the available sources.
Breeding
There are no published breeding accounts for Lamontichthys avacanoeiro, in the wild or in captivity. Reproductive mode, clutch size, spawning site, and parental care are all unrecorded. Given the species' rarity, Endangered status, and near-total absence from the aquarium trade, captive breeding data is not expected in the near term.
In the aquarium
Lamontichthys avacanoeiro is essentially not present in the ornamental trade and no aquarium husbandry has been documented for it. Any keeping would, by inference from the genus, demand cool to warm clear water with strong, well-oxygenated current and a clean substrate — conditions matching its rheophilic origins — but no tested parameters exist for this species. Given its Endangered listing and restricted range, it should be regarded as a wild species of conservation concern rather than an aquarium candidate.
Conservation
The IUCN Red List assesses Lamontichthys avacanoeiro as Endangered (EN) under criterion A3c, with the assessment dated 7 November 2018. The listing reflects a severely restricted distribution — the species is known only from the upper rio Tocantins — combined with a projected population decline driven by habitat loss. The principal threat is the alteration of its fast-flowing riverine habitat by damming and impoundment, which converts the clear, current-fed channels that rheophilic loricariines depend on into slack-water reservoirs.
Because the entire known range falls within a single basin under active hydroelectric pressure, the species has little geographic buffer against further habitat conversion. CITES has not evaluated it. The combination of narrow endemism and ongoing dam-driven habitat decline makes this one of the more genuinely threatened whiptail catfishes on record.