Taxonomy & naming
Microlepidogaster longicolla was described by Bárbara B. Calegari and Roberto E. Reis in 2010 in Neotropical Ichthyology (volume 8, number 3, pages 625–630). The type material was collected in the upper reaches of the rio São Bartolomeu, a tributary of the rio Corumbá, which in turn drains to the rio Paranaíba within the upper rio Paraná basin of central Brazil, near Brasília. The Catalog of Fishes (Eschmeyer, CAS) recognises the species as valid.
The genus Microlepidogaster belongs to the subfamily Hypoptopomatinae, the dwarf or 'otocinclus-like' loricariids, one of the major subfamilial lineages within the family Loricariidae. These are small, slender-bodied suckermouth catfishes of clear-water streams across eastern and central South America.
The specific epithet longicolla refers to the elongated predorsal region of the body, a consequence of the dorsal fin being set unusually far back along the trunk — a diagnostic feature the describing authors used to separate it from its congeners.
Morphology
Microlepidogaster longicolla is a small loricariid reaching about 2 in in standard length. The body is elongate, with a notably long predorsal region produced by the posterior placement of the dorsal fin — the trait that gives the species its name. Fin counts recorded in the original description include two dorsal-fin spines, seven dorsal-fin soft rays, and six anal-fin soft rays; vertebral counts range from 31 to 33.
Like other Hypoptopomatinae, the body is clad in the bony lateral plates (scutes) characteristic of the family and bears a ventral suckermouth. Detailed colour-in-life data beyond the type material is sparse; FishBase holds a photograph of a female specimen.
Habitat
The species is known from the upper reaches of the rio São Bartolomeu and associated headwaters of the rio Corumbá–Paranaíba drainage in the upper rio Paraná basin, in the vicinity of Brasília, central Brazil. It is a freshwater, demersal fish of tropical streams.
Specific microhabitat measurements — temperature, pH, current, and substrate — were not detailed in the sources available, so no precise field water chemistry is published here. As a member of a clear-water stream lineage, it can reasonably be expected in shallow flowing headwater habitats, but exact conditions are not documented.
Feeding
No diet study specific to Microlepidogaster longicolla has been published. Members of the Hypoptopomatinae are generally aufwuchs grazers, rasping the biofilm of algae, diatoms, and associated micro-organisms from rock, wood, and plant surfaces with their suckermouths. A comparable grazing habit is plausible for this species, but in the absence of direct dietary data it is noted here only as a genus-level expectation rather than a confirmed observation.
Mating
Courtship and spawning behaviour of Microlepidogaster longicolla have not been documented. The species displays marked sexual dimorphism (described under Breeding), but no observations of mating in the wild or in captivity are available in the sources consulted.
Breeding
No reproductive biology — clutch size, spawning site, or parental care — has been published for Microlepidogaster longicolla. The species does, however, show pronounced sexual dimorphism noted in its original description: males bear a conical urogenital papilla, a fleshy flap along the dorsal margin of the thickened first pelvic-fin ray, and a longer pelvic fin, whereas females have a more strongly arched first pelvic-fin ray. These differences are characteristic of mature individuals but the details of how they translate into spawning behaviour remain undescribed.
In the aquarium
Microlepidogaster longicolla is not an established aquarium fish. It is known almost entirely from scientific collections, and no husbandry, importation, or captive-care information is available. Given its small size and headwater-stream origin it would, like other dwarf Hypoptopomatinae, in principle require clean, well-oxygenated water and grazing surfaces — but no specific aquarium guidance can be offered without observed data, and none is published.
Conservation
The IUCN Red List assessed Microlepidogaster longicolla as Least Concern in 2018. As a recently described species with a restricted but apparently stable known range in headwater streams of the upper rio Paraná basin near a rapidly urbanising region (Brasília), it warrants monitoring, but it is not currently considered threatened. No targeted conservation measures specific to the species are documented.