Taxonomy & naming
Neoplecostomus botucatu was described by Roxo, Oliveira and Zawadzki in 2012, in Zootaxa (volume 3233, pages 1–21), as one of three new Neoplecostomus described together from the upper Rio Paraná system. The type specimens were collected from Córrego Águas de Madalena, a tributary of the Rio Pardo within the Rio Paranapanema basin, in the municipality of Botucatu, São Paulo State, Brazil.
The genus Neoplecostomus is the type genus of the subfamily Neoplecostominae, a lineage of small, stream-dwelling loricariids of south-eastern and southern Brazil. (FishBase lists the genus under Hypoptopomatinae, but the Catalog of Fishes and this atlas's taxonomy place it in Neoplecostominae.) The species is diagnosed in part by a reduced or absent adipose fin — a condition it shares within the genus only with N. paranensis — together with conspicuous dark spots scattered across the body, a comparatively deep head, and a wider mandible than N. paranensis.
Morphology
Neoplecostomus botucatu is a small loricariid reaching about 4 in in standard length in the known (male or unsexed) material. The body is elongate, clad in the bony plates characteristic of the family. Two features stand out in the original diagnosis: the adipose fin is absent or strongly reduced, and the body bears conspicuous dark spots distributed across its surface. Compared with the related N. paranensis — the only congener that also lacks a well-developed adipose fin — N. botucatu has a greater head depth (about 55.6–63.9% of head length) and a broader mandible (about 12.5–17.8% of head length).
Detailed published data on sexual dimorphism specific to this species are sparse. Many Neoplecostomus develop enlarged odontodes on the head and pectoral region in mature males, but the cache material does not document the condition for N. botucatu, so no claim is made here.
Habitat
The species is known only from its type locality, Córrego Águas de Madalena, a tributary of the Rio Pardo in the Rio Paranapanema basin of the upper Rio Paraná system, near Botucatu in São Paulo State, Brazil. It is a freshwater, demersal, tropical fish — a bottom-associated stream dweller, in keeping with the small-stream ecology typical of the genus.
No detailed in-situ water-chemistry measurements (temperature, pH, conductivity) are published for this species in the available sources, so figures are not given here. The single-stream distribution makes this a microendemic, a circumstance directly reflected in its conservation status.
Feeding
No species-specific feeding study is published for Neoplecostomus botucatu in the available sources. Neoplecostomus are small benthic loricariids that typically graze the biofilm — algae, diatoms, and associated micro-organisms and detritus — coating rocks and gravel in clear, flowing streams, but for this species specifically the diet has not been documented and is left unstated.
Mating
No data on courtship or mating behaviour have been published for this species. It is not present in the aquarium hobby, and its biology is known almost entirely from preserved type material.
Breeding
No reproductive data — spawning mode, clutch size, or parental care — are published for Neoplecostomus botucatu. Some loricariids in related lineages guard egg clutches deposited on or under stream substrate, but no such observation is documented for this species, and none is asserted here.
In the aquarium
Neoplecostomus botucatu is not a hobby species. It carries no L-number, is not traded, and has no husbandry record. Given its Critically Endangered status and single-stream range, it should be regarded strictly as a subject of conservation and scientific interest rather than an aquarium fish.
Conservation
The IUCN Red List assessed Neoplecostomus botucatu as Critically Endangered (CR) on 18 May 2022, under criteria B2ab(iii). This is among the most severe categories the Red List applies — a species judged to face an extremely high risk of extinction in the wild. The assessment follows directly from the fish's status as a single-site microendemic: it is known only from one small stream, Córrego Águas de Madalena, near Botucatu.
With such a constricted range, any local degradation of that stream — pollution, sedimentation, water abstraction, or habitat alteration from agriculture and urban expansion in the densely settled upper Paraná region — could affect the entire known population at once. A species occupying a single locality has no spatial buffer against a localised catastrophe, which is precisely the concern the B2ab(iii) criteria capture: a very small area of occupancy combined with continuing decline in habitat quality. Protection of the type-locality stream is therefore the central conservation priority for this fish.