Taxonomy & naming
Hypostomus velhomonge was described by Lustosa-Costa, Ramos, Zawadzki, and Lima in 2022, in a review paper published in Neotropical Ichthyology. The paper examined all Hypostomus material from the Parnaíba River basin of northeastern Brazil, redescribing the four previously known species (H. johnii, H. leucophaeus, H. meleagris, and H. unae) and recognising H. velhomonge as a fifth, new species.
The holotype (UFPB 9565) was collected on 8 February 2009 from the Rio Balsas, a tributary of the Parnaíba River, in Maranhão State, Brazil. A second measured specimen reached 5 in SL. The Catalog of Fishes (Eschmeyer, CAS) recognises Hypostomus velhomonge as a valid species.
The species is distinguished from its congeners in the basin by high tooth counts (62–95 premaxillary teeth, 64–110 dentary teeth), a wide dental angle of 115–135°, rounded dark spots on a lighter background, and a naked anteromedial region of the abdomen — that is, the central front portion of the belly lacks the small platelets present in related species. These characters in combination separate it from all other Parnaíba Hypostomus.
Morphology
The holotype measures 4.5 in (approximately 4.5 in) SL; the largest recorded specimen reached 5 in SL, suggesting a maximum adult size of roughly 4.5–5 in SL. The body follows the characteristic Hypostomus plan: broad, flattened head with a ventral sucking disc, keeled bony scutes covering the body, and a tapering caudal peduncle.
Coloration is described as rounded dark spots on a lighter background — a pattern that differs from some congeners in the basin and helps distinguish the species in the field alongside the naked anteromedial abdominal region, which is a particularly useful and stable morphological character.
The dentition is notably rich: 62–95 teeth on the premaxilla and 64–110 on the dentary, with a wide dental angle of 115–135°. This high tooth count and wide angle suggests an effective grazing apparatus, consistent with feeding from flat, hard surfaces. Sexual dimorphism has not been described for this species.
Habitat
Hypostomus velhomonge is endemic to the Parnaíba River basin in northeastern Brazil, found in the upper and middle portions of the basin within Maranhão and Piauí states. The Rio Balsas type locality is a Parnaíba tributary in the Cerrado plateau of Maranhão.
The Parnaíba is an independent Atlantic-draining basin — not connected to the São Francisco or Amazon systems — rising on the Cerrado plateau and flowing roughly 1,311 mi northeastward before reaching the sea at the Parnaíba Delta. The river drains a transition zone between the Cerrado savanna biome in its upper reaches and the semi-arid Caatinga in the lower basin; the species is restricted to the upper and middle basin, where Cerrado-influenced conditions prevail.
Rivers in this zone typically carry warm water (approximately 77–86 °F), near-neutral pH (around 6.5–7.5), and are subject to pronounced seasonality driven by the Cerrado's wet (November–April) and dry (May–October) seasons. During the dry season, rivers shrink considerably and water temperatures can rise. Rocky and sandy substrates with submerged wood are typical Hypostomus microhabitats in this region.
Feeding
No diet data specific to Hypostomus velhomonge have been published. The high tooth counts (up to 110 dentary teeth) and wide dental angle suggest an efficient scraping apparatus well-suited to rasping algal biofilm, periphyton, and fine detritus from flat rocky or woody surfaces — the standard aufwuchs-scraper feeding mode found across Hypostomus.
In the Parnaíba basin's Cerrado-influenced rivers, rocky substrates and submerged wood in moderate current would be primary foraging surfaces, with biofilm and algal growth dependent on light availability and water clarity across seasons.
In captivity, the standard loricariid diet of algae wafers, sinking pellets, and blanched vegetables would be appropriate, with driftwood available for biofilm grazing.
Mating
Mating behaviour has not been documented for Hypostomus velhomonge. By analogy with the genus, seasonal breeding tied to the onset of the Cerrado wet season — when river levels rise, water cools somewhat with rainfall, and food availability increases — would be expected. Male territorial behaviour around crevices and caves in rocky substrate is the general pattern across Hypostomus, but no observations specific to this species have been recorded.
Breeding
Breeding biology is undocumented for Hypostomus velhomonge. The species is not known to be in the aquarium trade, and no captive breeding reports exist. Cave-spawning with paternal guarding of adhesive eggs is the expected mode by analogy with other Hypostomus, but clutch size, incubation period, and fry behaviour have not been recorded.
In the aquarium
Hypostomus velhomonge is not present in the aquarium hobby, and no husbandry information has been published. Its small maximum recorded size — under 5 in SL, perhaps 6–6.5 in total length — would make it one of the more manageable Hypostomus in a tank context if it were available, comparable in scale to species such as H. punctatus that hobbyists occasionally keep.
Water parameters reflecting the upper Parnaíba basin would be appropriate: temperature 77–86 °F, pH 6.5–7.5, and moderate to low hardness. Rocky aquascaping with crevices and sheltered areas, combined with driftwood and a sinking diet of algae wafers and blanched vegetables, would suit the inferred biology. Minimal current requirements are not documented but moderate flow would be reasonable for a Cerrado river species.
Conservation
Hypostomus velhomonge has not been evaluated by the IUCN Red List. The species was described in 2022, and newly described freshwater endemics typically require several years before receiving a formal assessment.
As an apparent endemic to the upper and middle Parnaíba basin, the species has a geographically restricted range within a region subject to significant agricultural expansion, particularly soy cultivation and cattle grazing on the Cerrado plateau. Deforestation of riparian vegetation — which is critical for maintaining water quality, reducing sedimentation, and sustaining the submerged wood resources that Hypostomus depend on — is an ongoing pressure throughout the Cerrado biome. Whether the Parnaíba basin populations are stable, fragmented, or declining cannot be determined without dedicated fieldwork.