Taxonomy & naming
Neoplecostomus corumba was described by Zawadzki, Pavanelli and Langeani in 2008 in Zootaxa 1757: 31–48, a revision of Neoplecostomus from the upper Rio Paraná basin that erected three new species in the genus. The type locality is Córrego Gameleira, an affluent of the Rio Corumbá in the Rio Paranaíba basin, at approximately 17°59'S, 48°29'W, Corumbaíba municipality, Goiás State, Brazil. The specific epithet corumba is a noun in apposition referring directly to the Rio Corumbá drainage.
The Catalog of Fishes (Eschmeyer, CAS) recognises the valid combination Neoplecostomus corumba Zawadzki, Pavanelli & Langeani, 2008. FishBase assigns the species to Hypoptopomatinae following its subfamily treatment of the family; however, the literature places Neoplecostomus within its own subfamily Neoplecostominae, which is the classification used in the original description and in subsequent phylogenetic treatments. This site uses Hypoptopomatinae as a facet grouping for this species for consistency with the broader site facet structure.
Neoplecostomus corumba is distinguished from its closest relatives by a combination of characters: it lacks the enlarged odontodes and swollen skin along snout margins seen in mature males of N. selenae and N. yapo; it possesses a well-developed adipose fin (absent in N. paranensis); and it has 27–29 lateral-line plates, 15–24 premaxillary teeth, and 10–18 dentary teeth.
Morphology
Adults reach approximately 3 in standard length (SL) — FishBase records this as the maximum for unsexed or male specimens, with PlanetCatfish noting 3 in SL for museum material. The body is elongated and dorsoventrally depressed, with the greatest depth at the dorsal-fin origin; the trunk is dorsally rounded in cross-section rather than flat.
The head is wide and moderately depressed, with an obtuse snout in dorsal view. Lips are well developed: the lower lip carries papillae and reaches almost to the pectoral girdle, as expected in a species that scrapes biofilm and algae from hard surfaces. Teeth are long, slender, and bicuspid. The dorsal fin has one spine and 7 soft rays; the anal fin has one spine and 5 soft rays. The adipose fin is moderate to well developed and always present — a key character separating N. corumba from N. paranensis, which lacks it.
The most taxonomically significant secondary sexual character is a dorsal dermal flap on the pelvic-fin spine, present in males and absent in females. This structure, common in rheophilic loricariids, is thought to increase friction with the substrate in fast-flowing water, potentially aiding position-holding or nest guarding. Mature males of some Neoplecostomus species also develop enlarged odontodes, but this trait is notably absent in N. corumba males — a key diagnostic feature separating it from N. selenae.
Habitat
Neoplecostomus corumba is known from the Rio Corumbá system within the upper Rio Paraná basin, Goiás State, Brazil. The type locality, Córrego Gameleira, is a small tributary stream at approximately 18°S — a cerrado (Brazilian savanna) landscape dominated by gallery forest streams with rock, gravel, and sand substrates.
The distribution is centred on the Rio Paranaíba drainage, a major western tributary of the upper Paraná. No specific physico-chemical data from collection sites are recorded in the sources consulted. As a rheophilic loricariid typical of the Neoplecostomus clade, N. corumba is expected to occupy fast-flowing reaches with rock and gravel substrate in well-oxygenated streams, likely with moderate to strong current. The cerrado streams of Goiás experience seasonal variation in flow and temperature associated with the wet and dry seasons of the Brazilian interior.
Feeding
No gut-content studies specific to Neoplecostomus corumba are available in the sources consulted. The genus Neoplecostomus, based on morphology — ventrally positioned mouth, papillate lower lip reaching the pectoral girdle, fine bicuspid teeth — is aligned with algae scraping and biofilm grazing from hard substrates in flowing water, a feeding mode prevalent across rheophilic loricariids of the upper Paraná.
In aquaria, closely related Neoplecostomus species are reported to accept algae wafers, spirulina-based foods, and vegetable matter such as blanched courgette. Organic detritus and aufwuchs scraped from rocky surfaces likely form the core of the wild diet.
Mating
No behavioural observations of courtship or pair-bond formation have been documented for Neoplecostomus corumba in the wild or in captivity. The presence of the male pelvic-spine dermal flap is the sole sexually dimorphic character documented in the original description.
In rheophilic loricariids generally, males are expected to be territorial around nest sites in fast-water microhabitats — crevices, rock surfaces, or hollow spaces between boulders. Whether N. corumba follows this pattern is not confirmed by the available sources.
Breeding
No captive breeding of Neoplecostomus corumba has been reported in the sources consulted. The species is not established in the ornamental trade. Wild reproductive biology has not been documented in the available literature beyond the identification of males by the dermal flap on the pelvic spine.
By analogy with other small rheophilic loricariids from the upper Paraná, spawning in association with rocky substrate — possibly in sheltered crevices — with some degree of parental attendance is plausible, but this is an inference from family-level biology rather than documented observation for this species.
In the aquarium
Neoplecostomus corumba is not established in the aquarium hobby, and no husbandry accounts are available in the sources consulted. The genus Neoplecostomus rarely appears in trade; when specimens do circulate they are typically collected incidentally alongside other loricariids from the upper Paraná system and may be sold without identification.
A specialist stream-biotope setup with strong water movement, high dissolved oxygen, smooth rock and gravel substrate, and a mature algal film on rock surfaces would suit the species' ecology if it were ever obtained. Water parameters appropriate to upper Paraná cerrado streams — warm to moderately warm (roughly 72–81 °F), circumneutral pH, moderate hardness — are a reasonable starting point, though precise data for this species' collection sites are not available. Hobbyists keeping any Neoplecostomus should document parameters carefully, as very little is known about the group in captivity.
Conservation
The IUCN Red List assessed Neoplecostomus corumba as Least Concern in November 2018, based on its occurrence in the Rio Corumbá basin and no evidence of significant population decline at the time of assessment.
The upper Rio Paraná basin in Goiás State — cerrado biome — has experienced extensive conversion of native vegetation to agriculture (primarily soy, cotton, and cattle pasture), with associated impacts on stream hydrology, sedimentation, and water quality. Cerrado is one of the world's most threatened biodiversity hotspots, with the majority of its original extent already converted. Rheophilic stream fishes with restricted distributions, such as N. corumba, can be sensitive to changes in water flow and substrate quality caused by land clearing and stream modification. The species' current status should be monitored as agricultural pressures in its limited range continue.