Taxonomy & naming
Otothyropsis polyodon was described by Calegari, Lehmann A. and Reis in 2013. It is placed in the subfamily Hypoptopomatinae of the Loricariidae — the dwarf suckermouth or otocinclus-type armoured catfishes — within the genus Otothyropsis, a small group of miniature loricariids tied to the Paraná system.
The species epithet polyodon means 'many-toothed' and refers to the elevated tooth count of this fish relative to other members of Otothyropsis, a distinguishing feature noted at its description. Beyond the original publication, detailed taxonomic treatment is limited in the sources available here.
Morphology
Otothyropsis polyodon is a very small loricariid, reaching about 1.5 in standard length, with the depressed, bony-plated body characteristic of the dwarf Hypoptopomatinae. Its most cited distinguishing trait is a comparatively high tooth count, the basis for the name polyodon. Further details of coloration and external morphology are not reproduced in the available sources, and no sexual dimorphism has been documented.
Habitat
The species occurs in freshwater, demersal, tropical habitat in the upper rio Paraná basin of Brazil, where it is a bottom-associated fish of the drainage. Specific published data on water temperature, pH, hardness, and depth at its localities are not available in the sources to hand.
Feeding
No diet has been published for Otothyropsis polyodon. Dwarf hypoptopomatines of this form are generally biofilm and algae grazers, but in the absence of feeding data specific to this species, its diet should be treated as unrecorded.
Mating
No courtship or mating behaviour has been described for this species. Nothing reliable can be said about its reproductive interactions.
Breeding
There are no published breeding accounts for Otothyropsis polyodon. Reproductive mode, clutch size, spawning site, and parental care are all unrecorded in the available sources.
In the aquarium
Otothyropsis polyodon is not established in the aquarium trade and no husbandry has been documented for it. Any care expectations would have to be inferred from related dwarf rio Paraná hypoptopomatines — clean, gently flowing freshwater with grazing surfaces — but no tested aquarium parameters exist for this species.
Conservation
The IUCN Red List records Otothyropsis polyodon as Least Concern. The listing is consistent with a small benthic fish that is not known to face acute, range-wide threats, though the upper rio Paraná basin as a whole is subject to agricultural runoff, sedimentation, and hydrological alteration. As a recently described and poorly studied species, its population trends are not well documented, but it is not currently considered threatened.