Taxonomy & naming
Hoplisoma tenharim was described in 2026 by Shu Him Lam, Vinicius de Carvalho Cardoso Cassaro, Willian Massaharu Ohara and Murilo Nogueira de Lima Pastana, in Papéis Avulsos de Zoologia (São Paulo, volume 66, article e202666013), published 3 March 2026. It belongs to the genus Hoplisoma Swainson, 1838, within the subfamily Corydoradinae of the family Callichthyidae. Corydoradinae accounts for roughly 91% of Callichthyidae's diversity, and within that subfamily Hoplisoma is, alongside Corydoras, one of the most species-rich genera — a lineage resurrected in recent phylogenetic revisions of the group from within the old, broadly defined Corydoras. Hoplisoma tenharim was described directly into Hoplisoma from the outset, so unlike many corys familiar to aquarists it has never carried the name Corydoras in any formal sense. Eschmeyer's Catalog of Fishes treats Hoplisoma tenharim Lam, Cassaro, Ohara & Pastana, 2026 as a valid, currently accepted name.
The holotype (MZUSP 131487) was collected from the rio Manicoré under a bridge at kilometre 400.66 of the Trans-Amazonian highway (BR-230), in the municipality of Manicoré, Amazonas State, Brazil, with paratypes deposited at INPA and MZUSP. The describing team frames the discovery as biogeographically significant: Hoplisoma tenharim represents the first Corydoradinae species formally described from either the rio Manicoré or the rio Marmelos, two drainages of the rio Madeira basin in the Madeira-Tapajós interfluvial region that had previously lacked a confirmed cory of their own.
The specific epithet's derivation is not stated in the abstract-level material available to us. The type locality lies within the wider Rio Manicoré region, home to the Tenharim indigenous people and the Tenharim Indigenous Land; the name plausibly references this people or territory, but that connection is not confirmed by the source text we have access to, and no formal etymology section was available to verify it.
Morphology
No standard length has been recorded for Hoplisoma tenharim in the material available to us; the original description's morphometric tables and full body-plan description were not accessible for this article. As with other short-snouted Hoplisoma, the species is expected to follow the compact, deep-bodied, twin-scute-row plan typical of the genus, but specific proportions are not stated in the sources available here.
What is documented is the combination of characters used to diagnose the species from its congeners: four to five brownish-to-black blotches along the flank midline, similarly sized to or slightly larger than the remaining flank markings; a dark brown to black band across the medio-distal portion of the dorsal fin; the absence of conspicuous dark spots elsewhere on the head and trunk; a poorly developed ventral laminar expansion of infraorbital bone 1, reaching only to the transversal line through the dorsal portion of the preopercle; and a posterior portion of the supraoccipital bone that contacts the nuchal plate. These are comparative, largely osteological and pigmentation-pattern characters rather than a full coloration or morphometric account, and no photograph-based description of live coloration was available to us beyond the diagnostic pattern itself.
Habitat
Hoplisoma tenharim is known from the rio Manicoré and rio Marmelos drainages of the rio Madeira basin, spanning Amazonas and Rondônia States in the Brazilian Amazon. The type locality is the rio Manicoré itself, sampled under a bridge on the Trans-Amazonian highway (BR-230) near the town of Manicoré. No specific water-chemistry measurements (temperature, pH, depth, current) were available in the source material accessible to us, so no numeric range is asserted here beyond the drainage-level distribution documented in the original description and the Catalog of Fishes record.
Feeding
No dietary study has been published for Hoplisoma tenharim. As general genus-level context, rather than a documented finding for this species: Hoplisoma, like other Corydoradinae, are benthic omnivores and detritivores, sifting sand and fine substrate with the snout and barbels for small invertebrates, insect larvae and organic detritus.
Mating
No reproductive account has been published for Hoplisoma tenharim. As general genus-level context: Corydoradinae, including Hoplisoma, are egg-layers that shoal and typically court in the well-documented 'T-position', in which a male aligns at right angles against a receptive female's head, with a small number of eggs fertilised and then carried by the female in her pelvic-fin basket to be pressed onto a cleaned surface in small repeated batches. None of this has been directly observed in H. tenharim.
Breeding
There is no captive-breeding report for Hoplisoma tenharim, a species only recently brought to scientific attention. By analogy with other short-snouted Hoplisoma and Corydoradinae generally, spawning would be expected to follow the standard pattern seen across the group — a conditioned group with more males than females, triggered by a cool, oxygen-rich water change simulating seasonal rain, with adhesive eggs laid in small batches and no parental care — but this is inference from relatives, not documented practice for this species.
In the aquarium
Hoplisoma tenharim is not an established aquarium species; it was described only in 2026 and no hobby history is known to us. By analogy with related Hoplisoma and general cory husbandry, it would be expected to do well in a shoal of six or more over a soft, fine sand substrate that spares its barbels, in warm, well-oxygenated water reflecting Amazon lowland stream conditions, alongside peaceful small tankmates. As with all corys, gentle handling matters, since the fin spines snag easily in nets and a stressed individual can release a skin toxin dangerous in the confined water of a transport bag — but none of this is documented husbandry specific to the species, only inference from its relatives.
Conservation
Hoplisoma tenharim has not been formally assessed on the IUCN Red List, as is expected for a species described in 2026. The original description explicitly includes a discussion of biogeography alongside what the abstract describes as an 'imminent ecological threat' facing the species, though the specific nature of that threat is not detailed in the abstract-level material accessible to us. The paper's cited literature includes recent studies on Amazon deforestation-alert monitoring and logging-detection systems, along with research on how deforestation is altering the Amazon basin's hydrological cycle — a pattern of citation that suggests deforestation and logging pressure in the Madeira-Tapajós interfluve is a likely concern, though this inference is not confirmed by the accessible text and should be read as a reasonable guess rather than a documented finding.
As the first Corydoradinae species known from either the rio Manicoré or rio Marmelos drainages, H. tenharim also underscores how much of the fish diversity in this stretch of the Rio Madeira basin — an Amazon region already subject to substantial logging and land-use pressure — likely remains undocumented.