Taxonomy & naming
Microlepidogaster dimorpha was described by Oliveira Martins and Langeani in 2011 in Neotropical Ichthyology (volume 9, number 1, pages 79–86). It is a member of the family Loricariidae, subfamily Hypoptopomatinae — the dwarf suckermouth catfishes — and is treated as a valid species by the Catalog of Fishes (Eschmeyer, CAS).
The genus name Microlepidogaster combines Greek roots referring to the small scales (here, the bony plating) of the belly region. The specific epithet dimorpha is drawn from Greek di- (two) and morphe (form), a direct reference to the marked sexual dimorphism the authors observed in the species — notably the greater nostril width and pelvic-fin ray length in males.
Morphology
Microlepidogaster dimorpha is a small loricariid, reaching about 1.5 in standard length in the known material. The body is elongated and protected by the bony plates typical of the family. Published meristics record 8–9 dorsal soft rays, 5–7 anal soft rays, 18–21 mid-dorsal plates, and 29–30 vertebrae.
The species is notable for its sexual dimorphism. According to the original description, males display a wider nostril and longer pelvic-fin rays than females — the features for which the species is named. Beyond these characters, no further detail on live coloration is published in the consulted sources; FishBase carries no image of the species.
Habitat
The species is known from the rio Uberaba and the riacho Grotão, both tributaries of the rio Grande within the upper rio Paraná system of Brazil. It is a freshwater, demersal fish of tropical headwater streams.
Like other members of its genus, Microlepidogaster dimorpha is a facultative air-breather, an adaptation that suits small, shallow watercourses where dissolved oxygen can fluctuate. Specific data on the substrate, flow, and water chemistry at the collection sites are not detailed in the consulted sources.
Feeding
No dietary study specific to Microlepidogaster dimorpha is available in the consulted sources. As a small hypoptopomatine loricariid with a ventral suckermouth, it can reasonably be expected to graze biofilm — the film of algae, diatoms, and associated micro-organisms — from submerged surfaces, which is the general feeding mode of the subfamily. Direct dietary observations have not been published.
Mating
No courtship or mating behaviour has been documented for Microlepidogaster dimorpha in the consulted sources. The pronounced sexual dimorphism described by the authors — wider nostrils and longer pelvic-fin rays in males — suggests that these characters may play a role in reproduction or sex recognition, but no behavioural observations are published to confirm this.
Breeding
No breeding data have been published for Microlepidogaster dimorpha in the consulted sources. Spawning mode, clutch size, egg deposition, and any parental care all remain undocumented.
In the aquarium
Microlepidogaster dimorpha is a small, range-restricted headwater species with no established presence in the aquarium hobby, and no husbandry information is available in the consulted sources. It is documented here as a wild species rather than an aquarium subject.
Conservation
The IUCN Red List assessed Microlepidogaster dimorpha as Least Concern (LC) on 7 November 2018 (assessment current as of Version 2025-2). Although the species has a restricted known range in the upper rio Paraná headwaters, it was not considered to face threats sufficient to warrant a higher category at the time of assessment. The consulted sources do not detail specific threats to its habitat.