Taxonomy & naming
Harttia villasboas was described by Oyakawa, Fichberg and Rapp Py-Daniel in 2018, in Zootaxa (volume 4387, number 1, pages 75–90), in a revisionary study of the genus. The type material was collected in the Serra do Cachimbo, within the Rio Xingu basin, Pará, northern Brazil. The Catalog of Fishes (Eschmeyer, CAS) recognises Harttia villasboas as valid (spid 75252).
The genus Harttia belongs to the subfamily Loricariinae, the elongate whiptail lineage of the armoured catfishes (Loricariidae). The specific epithet villasboas is a patronym honouring the Villas Bôas brothers — Orlando, Cláudio and Leonardo — frontiersmen of the Expedição Roncador-Xingu and noted figures in the exploration and indigenous advocacy of the Xingu region.
Morphology
Harttia villasboas is a comparatively small member of the genus, reaching about 5 in in standard length, this figure being based on the type specimen (FishBase Ref. 117418). The body has an oval cross-section, distinguishing it from some flatter-bodied congeners.
The original description diagnoses the species by an abdomen completely covered by minute plates, a caudal peduncle slightly compressed laterally behind the convergence of the lateral keels, a comparatively greater head length, and a snout bearing a prominent medial longitudinal ridge.
No data on sexual dimorphism in this species has been published.
Habitat
The species is known from the Serra do Cachimbo, an upland plateau drained by headwater tributaries of the Rio Xingu in Pará, northern Brazil. FishBase characterises H. villasboas as a freshwater, benthopelagic fish of tropical waters. These are clear, flowing upland streams of the Brazilian Shield.
No detailed field data on water chemistry, depth, or microhabitat for this species has been published beyond the general environment of the type locality. Its conservation assessment notes a restricted range confined to the Serra do Cachimbo headwaters.
Feeding
No direct dietary study of Harttia villasboas has been published. As with other Loricariinae, it is presumed to be a benthic grazer that rasps biofilm, algae, and fine detritus from hard surfaces in flowing water, but this has not been confirmed for the species by gut-content analysis.
Mating
No information on the courtship or mating behaviour of Harttia villasboas has been published.
Breeding
No breeding data for Harttia villasboas has been published. Its spawning mode, clutch size, and parental care are undescribed, and there are no records of captive reproduction.
In the aquarium
Harttia villasboas is not present in the aquarium trade, and no husbandry experience with it has been published. Given its narrow range and Critically Endangered status, it is a species of conservation and scientific concern rather than a candidate for the hobby, and collection for ornamental purposes would be inappropriate.
Conservation
Harttia villasboas is assessed as Critically Endangered on the IUCN Red List, under criteria B1ab(iii)+2ab(iii), with the assessment dated 17 November 2020. This category reflects a very small geographic range — the species is restricted to the headwaters of the Serra do Cachimbo in the Rio Xingu basin — combined with a continuing decline in the extent and quality of its habitat.
The upper Xingu and the Brazilian Shield uplands face intensifying pressures from deforestation, mining, and hydroelectric and agricultural development, all of which degrade the clear upland streams on which a narrow-range endemic like H. villasboas depends. With a single, restricted known range and an ongoing habitat decline driving its listing, the species is among the most acutely threatened in the genus, and any further loss or alteration of its headwater streams could imperil it. Protection of the Serra do Cachimbo watercourses is essential to its survival.