Taxonomy & naming
Ancistrus mattogrossensis was described by Alipio de Miranda Ribeiro in 1912 in a publication covering Loricariidae, Callichthyidae, Doradidae, and Trichomycteridae (Annexo no. 5, page 5). The name refers to the Brazilian state of Mato Grosso, from which the type material was collected. An orthographic variant, Ancistrus mattogrossenssis (with a doubled 's'), appears in some older literature and databases but refers to the same taxon.
FishBase lists A. mattogrossensis as a valid name while explicitly flagging that 'validity of species not confirmed here' — an unusual qualification that reflects the state of the literature: the species was described over a century ago from material associated with a geographically broad and poorly pinpointed type locality, and modern taxonomic revision using morphological and molecular tools has not yet definitively resolved its status among the hundreds of Ancistrus species and synonyms.
The Catalog of Fishes (Eschmeyer, CAS) is the authoritative source for valid names in this family; researchers consulting the current CoF entry for this name should treat it as the primary reference for accepted status. The species belongs to the tribe Ancistrini, subfamily Hypostominae, family Loricariidae.
The specific epithet mattogrossensis is a latinised toponym: Matto Grosso (modern spelling: Mato Grosso) is the Brazilian state whose name translates from Portuguese as 'thick forest' or 'dense scrubland', and the suffix -ensis indicates origin from that place.
Morphology
No size data for Ancistrus mattogrossensis appear in the primary sources consulted for this cache; FishBase lists maximum length as not given. Without a reliable standard length figure, placing this species within the size range of the genus is not possible from current records alone.
The genus Ancistrus in general is characterised by a dorsoventrally flattened body encased in keeled bony scutes, a ventral sucker-mouth with fine multi-cusped teeth suited to algae rasping, and the diagnostic interopercular spines (odontodes) that project from the cheek region in both sexes. Adult males develop elaborately branched fleshy tentacles on the snout — the defining 'bristlenose' character — while females may have short marginal snout tentacles at most. These generic features can be assumed to apply to A. mattogrossensis, but species-specific morphometric data, colouration descriptions, and meristic counts are not reproduced in the secondary sources available here. Data sparse.
Habitat
The type locality of Ancistrus mattogrossensis is recorded simply as Mato Grosso, Brazil, with no more precise coordinates or hydrological data given in the original 1912 description. This imprecision is common in early twentieth-century Brazilian fish collections, which often accumulated material without exact station data. Mato Grosso state drains into multiple major river systems — including headwaters of the Tapajós, the Paraguay, and the Xingu — so the original collection could in principle represent any of several biogeographically distinct drainages.
FishBase places the species in South America with distribution in Mato Grosso. Without a more precise type locality, habitat characterisation rests on the broadly benthic, freshwater, tropical assignment recorded in FishBase and on the general expectation for a loricariid of this subfamily: riverbed or stream substrate, likely associated with hard surfaces (rock, root, or submerged wood) in warm, lowland or transitional freshwater environments. No water-chemistry data are available for this species. Data sparse.
Feeding
No species-specific dietary data for Ancistrus mattogrossensis appear in the sources available to this cache. Given its placement in the genus Ancistrus, it is reasonable to expect a broadly herbivorous and biofilm-grazing feeding strategy typical of the group — rasping algae, periphyton, and detritus from hard substrate surfaces. PlanetCatfish applies the standard genus husbandry note to its entry: primarily vegetarian, with algae wafers, spirulina-based sinking foods, and supplemental vegetables (courgette, cucumber) appropriate in captivity.
Beyond this genus-level inference, nothing more specific about A. mattogrossensis diet is supported by the available data.
Mating
No observations of mating behaviour specific to Ancistrus mattogrossensis are on record. The species is expected to share the territorial, cave-focused mating system documented across the genus: adult males defend cave or crevice sites, display snout tentacles to conspecifics, and attract females seeking established cavity territories. Female preference for males already brooding eggs, documented in other Ancistrus species, likely applies here as a genus-level trait.
The entirely generic status of these inferences is noted; without captive observations or field study of this particular taxon, confidence in species-specific mating details is low. Data sparse.
Breeding
Ancistrus mattogrossensis is presumed to breed as a cave-spawner with paternal brood care, in keeping with the universal reproductive pattern of the genus. No captive breeding record for this species is on file at PlanetCatfish, which lists only two registered keepers in its community database — an indication that the species is essentially absent from the active hobby.
Genus-level breeding parameters (adhesive eggs on cave walls, 4–10 day incubation, paternal fanning and guarding, fry dispersal after yolk absorption) are documented in the literature (see, for example, the IUCN accounts for related Ancistrus species), but applying these figures to A. mattogrossensis specifically carries inherent uncertainty given the unresolved taxonomic status of the species. Data sparse.
In the aquarium
Ancistrus mattogrossensis is not established in the ornamental trade. PlanetCatfish records only two keepers in its global community database — comparable to the baseline for a species known almost entirely from museum specimens rather than live imports. The common name 'Bristlenose Catfish' applied in the PlanetCatfish entry is a generic English label applicable to many Ancistrus species, not a trade name specific to this taxon.
The taxonomic uncertainty flagged by FishBase ('validity not confirmed here') is relevant to anyone attempting to identify a specimen as this species: without a modern revision and diagnostic key that includes A. mattogrossensis, confident species-level identification of living fish from Mato Grosso as this particular taxon is not possible. The standard Ancistrus aquarium protocol — vegetarian diet, cave provision, clean well-oxygenated water — would apply if specimens were kept, but no published husbandry notes specific to this species exist. Data sparse.
Conservation
Ancistrus mattogrossensis has not been evaluated by the IUCN Red List and carries a status of Not Evaluated (NE). Given the uncertainty over the validity of the species itself — as flagged by FishBase — a formal conservation assessment would first require taxonomic resolution to confirm that A. mattogrossensis represents a distinct, diagnosable species rather than a synonym of another Ancistrus already in the literature.
Mato Grosso state has experienced substantial deforestation and land-use change over recent decades, with significant conversion of the Cerrado and transitions into agricultural areas affecting river catchments. Without knowledge of the precise type locality and current population, no meaningful assessment of conservation risk can be made. Until a modern revision addresses the taxonomic standing of this 1912 name, its conservation relevance remains indeterminate.