Taxonomy & naming
Corydoras maclurei was described in 2023 by Luiz Tencatt, Willian Ohara and Hans-Georg Evers, in Neotropical Ichthyology, from tributaries of the rio Araza — an affluent of the rio Inambari, in the rio Madre de Dios (upper rio Madeira) basin of the Peruvian Amazon. In the hobby the fish had circulated for years under the collection code CW016. The species is named in honour of Robert 'Rob' McLure, a well-known Corydoradinae breeder and long-time English-language reviewer of the lead author's papers.
The description is notable because the authors used it to address a long-standing muddle over the true identity of Corydoras aeneus, the ubiquitous bronze cory — a name that had been applied loosely to a swarm of similar bronze-bodied populations across the continent. C. maclurei is one of those aeneus-like fish given its own name. Taxonomically it belongs to the 'aeneus group' (Alexandrou et al.'s lineage 5), which the 2024 revision by Dias, Tencatt and colleagues raised to the resurrected genus Osteogaster. Under that scheme the species becomes Osteogaster maclurei; we keep the hobby-familiar 'Corydoras maclurei' as the heading and record the new combination. The Catalog of Fishes (Eschmeyer, CAS) treats the name as valid.
Morphology
In overall build Corydoras maclurei is a typical bronze-group cory: a small, fairly stocky, deep-bodied armoured catfish with the usual twin rows of overlapping bony plates down each flank, a hard helmeted head, a downturned mouth fringed by three pairs of barbels, and stiff, mildly venomous leading spines in the dorsal and pectoral fins. At a glance it closely resembles an ordinary bronze cory, which is precisely why it was overlooked for so long.
What distinguishes it is colour and a skeletal detail. The body carries a single large, conspicuous dark brown or black blotch on the upper-front part of each flank — rounded to roughly diamond-shaped — standing out against an otherwise plain, metallic greenish-bronze ground, with no dark blotches on the fins. Internally the describers diagnose it by the absence of contact between the posterior process of the parieto-supraoccipital and the nuchal plate on top of the head. As is usual in the genus, mature females are larger and rounder-bodied than the slimmer males.
Habitat
The species is known from tributaries of the rio Araza in the rio Inambari drainage, part of the rio Madre de Dios basin in the south-eastern Peruvian Amazon — upper rio Madeira system. These are warm lowland Amazonian waters: streams and river margins over sand and fine sediment, with leaf litter and submerged wood, of the kind favoured by bronze-group corys throughout the basin.
Detailed published chemistry for the type localities is limited, but conditions are those of warm, soft, slightly acidic to neutral Amazonian lowland water, with the genus comfortable across roughly 72–81 °F and a pH band around 6.0 to 7.5. Like all Corydoras it is a facultative air-breather, surfacing to gulp atmospheric air absorbed through a vascularised hindgut — an adaptation that suits the warm, sometimes oxygen-poor backwaters and shrinking pools of its habitat.
Feeding
Corydoras maclurei is a benthic omnivore and detritivore in the bronze-cory mould. It forages over the bottom, burying snout and barbels in sand to taste out small invertebrates, insect larvae, worms, micro-crustaceans, fallen seeds and organic detritus, expelling cleaned sand through the gills as it goes — an opportunist rather than a specialist. In the aquarium its relatives readily take sinking pellets and tablets, frozen and live bloodworm, daphnia and brine shrimp, and graze whatever settles to the substrate, though they should be fed a proper share rather than left to scavenge.
Mating
Reproduction has not been documented specifically for this newly described fish, but the bronze-group corys it belongs to are among the best-studied spawners in the genus, and the pattern is expected to apply. They are egg-scattering shoalers with no pair bond. A ripe female cleans a spawning site while the group becomes active; a male takes the classic 'T-position' at right angles to her head, and the female takes milt into her mouth, passing it rapidly through her gut to fertilise the small clutch she clasps in a basket formed by her pelvic fins, then presses the eggs onto the cleaned surface. The bout repeats a few eggs at a time until dozens of sticky eggs are scattered across the chosen surfaces.
Breeding
No species-specific breeding report exists yet for Corydoras maclurei, but as a member of the readily-bred aeneus group it should follow the familiar, easy protocol of its close relatives. Spawning is typically triggered by a large, cooler water change mimicking the onset of the rains, in a mature group skewed towards more males than females. The adhesive eggs — laid in small batches and likely on the order of dozens to a couple of hundred — receive no parental care, as the adults eat them, so a breeder removes either the eggs or the parents. Eggs hatch in roughly three to five days, and the fry take microworm, baby brine shrimp and powdered foods once the yolk sac is absorbed. Aquarium stock currently derives largely from wild-collected Peruvian imports.
In the aquarium
For the keeper, Corydoras maclurei behaves as a bronze cory with a distinctive shoulder spot, and it asks for the same care as its hardy relatives. It is a shoaling species and should be kept in groups of six or more, never singly or in pairs; given numbers it forages confidently throughout the day. A tank with a footprint of around 23.5 in / 20 US gal or more suits a group, bottom area mattering more than height.
Provide soft sand or very fine, smooth, rounded gravel — corys feed by sifting, and coarse or sharp substrate abrades and infects their barbels, leaving the blunted faces that signal poor husbandry — and keep the bottom clean. Warm, soft, slightly acidic to neutral water (about 72–79 °F), well filtered and well oxygenated with a gentle current and regular changes, mirrors its home waters while remaining within a forgiving range. It is utterly peaceful and suits a community of tetras, pencilfish, rasboras, dwarf cichlids and other calm fish, never anything large enough to bully it. The usual cory cautions hold: the fin spines catch in nets, so a cup is safer for moving them, and a badly stressed cory can release a skin toxin that, in the confined volume of a transport bag, can wipe out the whole group.
Conservation
Corydoras maclurei has not been assessed by the IUCN Red List, which is unsurprising for a species described only in 2023, and it therefore has no formal conservation status. It is known from a restricted area of the rio Araza/Inambari in the Madre de Dios basin — a region of south-eastern Peru under pressure from gold mining, deforestation and the sediment and mercury pollution that accompany them, all of which degrade the clear lowland streams bronze corys depend on. Against that, the broader aeneus group is ecologically flexible, and the fish's full range may prove wider than the type localities suggest. For now, with no assessment and a recently clarified identity, its population status is genuinely unknown.