Taxonomy & naming
Hypostomus guajupia was formally described by Penido, Pessali and Zawadzki in 2021, published in the Journal of Fish Biology (volume 98, number 5, pages 1371–1384). The holotype, MZUSP 125968, measures 7.5 in standard length and was collected from the Rio Paraopeba downstream of the Retiro Baixo hydroelectric dam, municipality of Curvelo, Minas Gerais, Brazil (approximately 18°52′23″S, 44°46′52″W). The species is placed within the large genus Hypostomus Lacépède, 1803 — the most species-rich genus in Loricariidae — and is assigned to subfamily Hypostominae.
As a description published in 2021, H. guajupia is not yet indexed in the public version of FishBase and has not yet received a formal IUCN Red List assessment. The Catalog of Fishes (Eschmeyer, CAS) is the authority for the valid name and authorship cited here.
Morphology
The largest known specimen reaches 8 in standard length, placing H. guajupia among the larger members of the genus. The body is covered in the overlapping bony scutes characteristic of all loricariids. Colouration consists of large dark brown spots on a lighter brownish background — a pattern that differs from the fine-spotted or vermiculated designs seen in some congeners. The abdomen is partially plated rather than fully naked, and the species lacks lateral keels on the flanks. The mandibular ramus is proportionally shorter relative to body length than in related species, and the teeth are few and robust, a combination that helped distinguish H. guajupia from its congeners in the original description.
Habitat
Hypostomus guajupia is endemic to the upper São Francisco River basin in Minas Gerais state, southeastern Brazil. Confirmed records come from three tributaries: the Rio Itapecerica, Rio Pará, and the type-locality Rio Paraopeba, all draining the highland Minas Gerais plateau at altitudes of 1608–1969 ft above sea level. These are clear-water highland rivers with a seasonal thermal cycle typical of the Brazilian interior.
Field collections found individuals in deeper channel areas, typically 7–16 ft depth, hiding beneath or wedged between large boulders in areas of main river current — a microhabitat choice consistent with many large rheophilic Hypostomus. Water chemistry at these highland elevations is expected to be slightly acidic to near-neutral (pH approximately 6.5–7.2) with moderate temperatures of roughly 72–79 °F varying seasonally, though the description paper does not publish explicit water-chemistry measurements from collection sites.
Feeding
No specific dietary study has been published for H. guajupia. Based on genus-level biology and gut-content work on closely related Hypostomus, the species is presumed to be a generalist benthic grazer feeding primarily on periphyton — the biofilm of algae, bacteria, fungi, and fine detritus that coats hard substrates such as boulders and bedrock in clear highland rivers. The robust, few-toothed dentition described in the original paper is consistent with scraping firm surfaces rather than soft substrate mining. Loricariids of similar body size and microhabitat routinely supplement algal grazing with fine organic detritus and incidentally consumed invertebrates.
Mating
No observations of courtship behaviour specific to H. guajupia have been published. Across Hypostomus broadly, males establish and defend rock crevices or submerged cavity sites that serve as nest sites, and sexual dimorphism in odontode development — bony bristles on the cheeks and body — is typically more pronounced in reproductively active males. Given the species' preference for boulder-rich deep-channel habitat, suitable spawning cavities are likely found among the rock formations that also serve as daytime refuges.
Breeding
No breeding data specific to H. guajupia have been published. Hypostomus species are broadly characterised as cave spawners with paternal brood care: the male selects a sheltered cavity, the female deposits adhesive eggs on the interior surfaces, and the male fans and guards the clutch through incubation. Fry of large Hypostomus typically emerge already well-developed and begin grazing within days of hatching. Whether H. guajupia has been maintained in captivity at all is not known; it is not present in the ornamental trade.
In the aquarium
Hypostomus guajupia is not present in the aquarium trade and is known only from scientific field collections. At a maximum recorded size of approximately 8 in standard length — probably 10–10.5 in in total length — it would require substantial tank space if it ever entered the hobby. The deep-channel, boulder-crevice microhabitat of the São Francisco highland tributaries would be challenging to replicate authentically. No husbandry data are available.
Conservation
Hypostomus guajupia has not been assessed by the IUCN Red List; as a species described in 2021, it falls outside the current assessment cycle. Its known range is restricted to three tributaries of the upper São Francisco basin — a naturally limited distribution that heightens its vulnerability to localised threats.
The conservation context for this species is stark. The Rio Paraopeba, where the type specimens were collected, flows through the zone directly affected by the January 2019 failure of the Córrego do Feijão tailings dam at Brumadinho — the disaster that killed 259 people and released approximately 12 million cubic metres of iron-ore mining waste into the river system. The long-term effects of this catastrophic sedimentation event on benthic loricariid populations in the Paraopeba remain poorly documented. The Retiro Baixo hydroelectric dam, immediately upstream of the type locality, represents a further structural alteration to the river. Both pressures compound the vulnerability of a species with a geographically narrow range.