Taxonomy & naming
Hypostomus renestoi was described by Zawadzki, da Silva, and Troy in 2018 in a paper published in Ichthyological Exploration of Freshwaters. The paper's full scope was the redescription of Hypostomus latirostris (Regan, 1904) alongside the recognition of H. renestoi as a new species — the two taxa had previously been conflated, with H. renestoi catalogued informally as Hypostomus sp., sp. 3, and sp. 4 in earlier genetic and morphological studies from the upper Paraguay basin.
The type locality is the Rio Jungada (also spelled Rio Jangada), a tributary of the Rio Cuiabá in Mato Grosso State, Brazil, within the upper Rio Paraguay basin. The holotype measures 5 in SL. The species is valid per the Catalog of Fishes (Eschmeyer, CAS) and is confirmed in WoRMS.
The primary morphological characters distinguishing H. renestoi from H. latirostris include tooth robustness — H. renestoi has robust teeth, whereas H. latirostris possesses slender teeth — along with 28–77 premaxillary teeth and 25–64 dentary teeth, small and conspicuous dark spots on the body, and moderate hypertrophied odontodes on the dorsal and mid-dorsal plate series. The two species apparently occupy overlapping or adjacent drainages, and the redescription of H. latirostris was necessary to cleanly separate them.
Morphology
The holotype of Hypostomus renestoi measures 5 in (approximately 5 in) SL; the maximum size reached in the wild is not definitively established, but the general size range expected for this species is roughly 6–8 in SL based on the body form and comparison with close relatives.
The body is encased in the overlapping keeled scutes characteristic of the subfamily Hypostominae. The colour pattern features small, conspicuous dark spots on a lighter base — described as more noticeable in H. renestoi than in H. latirostris. The dorsal and mid-dorsal plate series carry moderate hypertrophied odontodes during the breeding season, a common feature of male Hypostomus across the genus.
The dentition is a key diagnostic character: teeth are robust, multicusped, and present in counts of 28–77 on the premaxilla and 25–64 on the dentary. This robust tooth morphology distinguishes H. renestoi from the slender-toothed H. latirostris and is consistent with a scraping diet from hard substrates. Sexual dimorphism specific to this species has not been formally documented, though male Hypostomus generally show enlarged interopercular odontodes during breeding season.
Habitat
Hypostomus renestoi is known from the upper Rio Paraguay basin in Mato Grosso State, Brazil, primarily from the Rio Cuiabá and its tributaries, including the type locality on the Rio Jangada. This portion of the upper Paraguay basin lies upstream of the Pantanal — the world's largest tropical wetland — and is characterised by clear to slightly turbid tropical rivers draining a transitional zone between the Cerrado savanna and the lowland Pantanal biome.
Water conditions in the upper Cuiabá drainage are warm and typically near neutral: temperatures of approximately 75–86 °F, pH around 6.5–7.5, and moderate conductivity are characteristic of rivers in this region. The dry-season rivers of the upper Paraguay basin can run clearer and warmer than the wet-season flood-diluted conditions.
Microhabitat preferences for this species have not been described in detail, but Hypostomus in similar environments typically inhabit rocky riffle zones, submerged root tangles, and hard-substrate areas in moderate current where food biofilm accumulates and crevices offer refuge.
Feeding
No diet data specific to Hypostomus renestoi have been published. The robust teeth and scraping dentition (28–77 premaxillary teeth, 25–64 dentary teeth) are characteristic of Hypostomus adapted to rasping algal biofilm, periphyton, and fine organic detritus from hard substrates — the classic aufwuchs-scraper feeding mode that predominates across the genus.
In the upper Paraguay drainage, rocky substrates with photosynthetic biofilm growth would be the primary foraging surface. Fine detrital organic matter accumulated in calmer sections of river may also contribute to the diet during low-water periods.
In captivity, the standard Hypostomus diet would be applicable: sinking algae wafers, blanched vegetables (courgette, cucumber, sweet potato), spirulina-based foods, and driftwood for biofilm rasping. Protein supplementation in the form of sinking pellets or occasional invertebrate foods can be offered but should not dominate the diet.
Mating
Mating behaviour has not been documented for Hypostomus renestoi. Across the genus, males typically claim and defend rocky crevices or undercut banks during the breeding season, developing more pronounced interopercular and dorsal odontodes as secondary sexual characteristics. Females, when conditioned and gravid, tend to be noticeably wider-bodied than males of the same length.
Seasonal triggers in the upper Paraguay basin likely include the onset of the wet season (November–March), when rising water, lower temperatures from rainfall dilution, and increased food availability cue spawning across many Neotropical catfish species.
Breeding
Breeding has not been documented for Hypostomus renestoi in the scientific literature or in hobbyist sources. The species is not known to be in the aquarium trade, and no captive breeding reports exist.
By analogy with the genus, cave-spawning with paternal guarding of adhesive eggs would be expected, but clutch size, incubation period, and parental care duration are unknown for this species specifically.
In the aquarium
Hypostomus renestoi is not present in the aquarium hobby and no husbandry information exists. The species' recent description (2018) and its origin in the interior rivers of Mato Grosso mean that it has not yet entered the trade.
Should specimens become available, water parameters reflecting the upper Paraguay basin would be appropriate: temperature 75–86 °F, pH 6.5–7.5, moderate hardness. A spacious aquarium with rocky decor, crevices for shelter, and moderate water flow would suit the biology inferred from its habitat. A diet based on algae wafers, sinking pellets, and blanched vegetables would provide adequate nutrition.
At an estimated adult size of 6–8 in SL (perhaps 7–10 in total length), this is a mid-sized catfish requiring an appropriately sized aquarium — at minimum 55 US gal for a single specimen.
Conservation
Hypostomus renestoi has not been evaluated by the IUCN Red List. The species was described in 2018, and newly described freshwater fish often take several years to receive a formal assessment.
The upper Rio Paraguay and Cuiabá drainage in Mato Grosso face significant pressures from agricultural expansion (soy cultivation and cattle ranching), deforestation of riparian buffers, and sedimentation from eroded soils — all of which degrade the rocky riffle habitats that Hypostomus species depend on. Until the species' range and population trend are formally evaluated, its conservation status remains unknown.