Taxonomy & naming
Astyanax maculisquamis was described by Garutti and Britski in 1997. Catalog of Fishes records the valid name as Astyanax maculisquamis Garutti & Britski, 1997, and the authority is confirmed by IRMNG registration (entry 1298368). The type locality lies within the upper Guaporé River basin on the Bolivia–Brazil border, placing the species in the southwestern portion of the Amazon drainage system.
Astyanax is among the most species-rich genera in the family Characidae and is distributed across Central and South America. Its members are characterised by a compressed, silvery body, a small adipose fin, and the complete lateral line typical of characids. Within the genus, species boundaries are often defined by meristic and pigmentation characters rather than dramatic colour differences, and A. maculisquamis is distinguished in part by the spotted-scale pattern reflected in its name.
Morphology
Astyanax maculisquamis reaches a maximum recorded size of 3 in standard length according to FishBase. Like other members of the genus it is a laterally compressed, silvery, fusiform characin carrying the standard characid bauplan: a single dorsal fin, a small adipose fin, a forked tail, and an adipose eyelid in adults.
The specific epithet directly references the most diagnostic pigmentation feature: maculisquamis, from the Latin maculatus (spotted) and squamis (scales), indicates a pattern of spots or markings on the scales. Published morphological and meristic data beyond size and this eponymous character are not available in the sources consulted, which is consistent with the species' sparse treatment in the literature since its original description.
Habitat
This species is endemic to the upper Guaporé River basin, a system that forms part of the Bolivia–Brazil border in the southwestern Amazon. The Guaporé (known as the Iténez in Bolivia) drains a transitional zone between the Bolivian Amazon lowlands and the Brazilian Cerrado fringe, with seasonally flooded várzea and gallery forest habitats typical of the broader basin.
FishBase classifies A. maculisquamis as benthopelagic and freshwater tropical. Specific water-parameter measurements for the upper Guaporé are not recorded for this species in the sources consulted, but the region's waters are generally warm, soft, and mildly acidic relative to harder Andean-influenced drainages further west.
Feeding
FishBase assigns A. maculisquamis a trophic level of 2.9 ± 0.4, estimated from closest relatives rather than from direct stomach-content analysis. This value places it among low-level omnivores, consistent with the opportunistic feeding ecology typical across Astyanax — small invertebrates, plant material, algae, and organic detritus taken from the water column and substrate.
No specific dietary data for A. maculisquamis in the wild have been published in accessible sources. Given the genus's well-documented trophic flexibility, individuals likely exploit whatever prey and plant matter are locally abundant across the seasonal flood cycle of the Guaporé system.
Mating
No specific mating observations have been published for Astyanax maculisquamis. By analogy with other Astyanax species, which are well-studied in the wild and in the laboratory, the species is expected to be an egg-scattering open spawner. Males typically court females with chasing behaviour and parallel swimming, releasing gametes over submerged vegetation or into the water column with no bond formation.
Most Astyanax species spawn seasonally, cued by rising water levels and temperature shifts at the onset of the flood season, which disperses adults into flooded vegetation where adhesive or semi-adhesive eggs are deposited among fine-leaved plants. No parental care is shown; eggs and fry are left to develop independently.
Breeding
No captive breeding records for Astyanax maculisquamis appear in the sources consulted, and the species is not recorded in the aquarium hobby via FishBase. Based on the genus, however, spawning would follow the standard Astyanax pattern: eggs scattered among fine-leaved aquatic plants or spawning mops, adhesive or semi-adhesive, with no parental care and adults removed after spawning to prevent egg predation.
Incubation across Astyanax species at tropical temperatures typically runs a few days, with fry free-swimming within a week of fertilisation. First foods would be infusoria and very fine commercial fry preparations, graduating to newly hatched brine shrimp as the fry grow. Given the lack of any documented aquarium maintenance for this species, these details remain inferential.
In the aquarium
Astyanax maculisquamis is not documented in the aquarium hobby and no maintenance data are recorded by FishBase or other sources consulted. If encountered, its care would be expected to follow the general requirements of small Astyanax species: a spacious tank with open swimming space, soft to moderately hard water in the tropical temperature range, and a varied diet of flake, small pellets, and frozen invertebrates.
As a schooling characin it would benefit from being kept in groups of six or more with similarly sized, peaceful tankmates. Data are too sparse to give specific aquarium guidance beyond these genus-level defaults.
Conservation
Astyanax maculisquamis is listed as Data Deficient (DD) by the IUCN, assessed on 04 March 2021 and documented via FishBase. A Data Deficient designation indicates insufficient information to assess extinction risk — not that the species is necessarily threatened, but that the biological and distributional surveys needed to evaluate its population status have not been conducted.
The species is endemic to the upper Guaporé basin, a relatively restricted drainage on the Bolivia–Brazil border. While this region is less heavily deforested than the eastern Amazon, it faces ongoing agricultural expansion, cattle ranching, and small-scale gold mining that affect water quality and riparian vegetation throughout the Guaporé drainage. Future assessments that draw on more thorough field surveys will be needed to determine whether the restricted range translates into any genuine conservation concern.