Taxonomy & naming
Corydoras lacrimostigmata was described by Luiz Tencatt, Marcelo Britto and Carla Pavanelli in 2014, in Neotropical Ichthyology, from tributaries of the rio Ivaí in the upper rio Paraná basin of Paraná State, southern Brazil. The epithet combines the Latin lacrima ('tear') and stigma ('mark'): it refers to the diffuse dark stripe between the corner of the mouth and the front of the eye, and the drop-shaped dark blotch on the rear of the infraorbital — markings that resemble teardrops. The authors distinguished it from most congeners partly by the presence of three nasal pores.
The species was described in the catch-all genus Corydoras Lacépède, 1803. The 2024 revision by Dias, Tencatt and colleagues split that artificial genus into several lineages using molecular phylogenetics, and assigns lacrimostigmata to the resurrected Hoplisoma Swainson, 1838 — giving the combination Hoplisoma lacrimostigmata, as carried by corydorasworld.com and FishBase. Because the hobby and most literature still say 'Corydoras lacrimostigmata,' we keep that heading and note the current combination here.
Morphology
This is a small cory; the largest specimen known measures about 1.5 in (roughly 1.5 in) standard length, with the holotype near 1.5 in. It has the standard Corydoras form — a deep, flat-bellied body armoured with two rows of overlapping bony scutes, a hard bony head and three pairs of barbels around the small downturned mouth, with stiff leading spines in the dorsal, pectoral and adipose fins.
The diagnostic features are facial. A diffuse dark stripe runs from the mouth corner to the front of the eye, and a drop-shaped dark blotch sits on the posterior infraorbital — the 'teardrop' markings of the name. The snout is slightly pointed and the dorsal profile of the head gradually concave; this separates it from the similar C. flaveolus, which has a more rounded snout and an abruptly concave head profile. Three nasal pores further set it apart from most relatives.
Habitat
Corydoras lacrimostigmata is known only from the rio Ivaí basin, a tributary of the rio Paraná in Paraná State, southern Brazil — the upper Paraná system, well south of the Amazon. The type locality is the rio Maria Flora, a tributary to the rio Ubazinho, near Cândido de Abreu. It is recorded from small tributary streams of that drainage.
These are subtropical-to-warm-temperate headwater streams of southern Brazil, generally clearer, cooler and more seasonal than equatorial Amazonian waters, over substrates of sand, gravel and leaf litter. Specific published water chemistry for the species is scarce, and as a southern upland fish it likely experiences a wider annual temperature swing than tropical lowland corys. Like all corys it is a facultative air-breather, surfacing to take air and absorb oxygen through its hindgut.
Feeding
Corydoras lacrimostigmata is a foraging benthic omnivore, like its relatives. In its stream habitat it works the bottom with its barbels, sifting sand and leaf litter for small invertebrates, insect larvae, worms and organic detritus. In the aquarium it is reported to accept sinking dried foods as well as small live and frozen items such as chironomid larvae (bloodworm) and Tubifex. No detailed dietary study of the species has been published; the picture is drawn from its anatomy and the consistent habits of the group.
Mating
No spawning of Corydoras lacrimostigmata has been documented, so its reproduction is inferred from the subfamily, whose courtship is uniform and well studied. Corys are egg-laying shoalers with no pair bond: a receptive female cleans a site, a male takes the characteristic 'T-position' at right angles to her head, she appears to take his milt into her mouth, and she fertilises the few eggs she cradles in a basket of her pelvic fins before pressing them onto the cleaned surface, repeating the sequence a few eggs at a time. Whether lacrimostigmata departs from this pattern is untested.
Breeding
There is no published account of Corydoras lacrimostigmata being bred in captivity; it is uncommon in the hobby and poorly documented. By analogy with the subfamily, any spawning would likely be triggered by a cool, heavy water change mimicking the seasonal rains — perhaps more pronounced for a southern, seasonally variable fish — and would yield a small clutch of adhesive eggs given no parental care, with the adults inclined to eat them. Until a confirmed breeding is recorded, this remains expectation rather than established fact.
In the aquarium
Corydoras lacrimostigmata is rarely available and remains poorly known in aquarium terms; it is not a beginner's staple. The general cory requirements apply: a soft sand substrate to protect the barbels from the erosion and infection that coarse or dirty gravel causes, a group of six or more for security, and clean, gentle, well-oxygenated water. Its southern upland origins suggest it would prefer cooler, clearer water than tropical lowland corys, and likely appreciates a degree of seasonal coolness; precise tested parameters are not established. It is a peaceful, sociable bottom-dweller best kept with calm, similarly small community fish. As with all corys, transport with care — a stressed fish can release skin toxins that may kill a whole group in the small volume of a bag.
Conservation
Corydoras lacrimostigmata has not been evaluated by the IUCN, so it carries no formal conservation status. It is a recently described species known only from the rio Ivaí drainage in Paraná State — a narrow, single-basin distribution that is itself a reason for caution, since a localised endemic can be far more vulnerable than a widespread species. The upper Paraná basin is among the more heavily developed regions of Brazil, with extensive agriculture, deforestation of riparian forest and dams on the main rivers, all of which degrade the small headwater streams this fish depends on. A formal assessment would be needed to judge its true status.