Taxonomy & naming
Rineloricaria harenae was formally described in 2026 by Beatriz Rodrigues da Cruz, Jonatas Santos Lima Pereira, Claudio Oliveira and Guilherme José da Costa Silva, in ZooKeys (issue 1269, pages 211-224). The Catalog of Fishes (Eschmeyer, CAS) recognises Rineloricaria harenae as a valid species with no synonyms.
Rineloricaria is the largest and taxonomically most difficult genus of whiptail catfishes within subfamily Loricariinae of the armoured catfish family Loricariidae. R. harenae was recovered as a well-supported, distinct lineage by mitochondrial COI barcoding and Bayesian phylogenetic inference under the GTR substitution model, corroborating its morphological diagnosis; the original description compares it directly with the geographically close Rineloricaria jaraguensis, sampled from the same cluster of Santa Catarina drainage basins.
The specific epithet harenae is the Latin genitive singular of harena ('sand'), matching the original description's own framing of the species as a 'sand-dwelling' Rineloricaria in both its title and abstract. A dedicated etymology section, if published, was not accessible in the sources consulted for this article, so this derivation should be read as inferred from the Latin construction and the paper's stated theme rather than quoted verbatim from the species' own etymology text.
Morphology
The holotype is a 3.63 in standard length (SL) male (LBP 35336), with a type series completed by 19 paratypes (LBP 9126, 14 specimens; MZUSP 131542, 5 specimens). Like other Rineloricaria, R. harenae has the elongate, dorsoventrally depressed, whip-tailed body plan typical of the Loricariinae, tapering to a long, thin caudal peduncle, with a ventral sucker-disc mouth used to hold station on the substrate.
The original description diagnoses R. harenae by a combination of characters: four lateral plate series with the mid-dorsal series absent; an abdomen only partially covered by central plates that fall short of the pectoral-fin insertion; plates of the central abdominal complex arranged in an approximately triangular pattern; a cleithral (scapular) region that is entirely naked or bears only a few small, isolated plates; and five dark transverse bars on the dorsal surface of the body. It shows the four lateral plate series, broad naked snout and filamentous upper caudal-fin ray typical of sand-dwelling Rineloricaria, but its abdominal plating pattern is unusually similar to that of rock-dwelling relatives — a combination the describing authors say raises new questions about the origin and functional role of ventral plating across the genus.
Habitat
Rineloricaria harenae is known only from its type locality on the Itapocú River in the municipality of Jaraguá do Sul, Santa Catarina State, Brazil (26°28'17.2"S, 49°10'55.1"W), part of the Eastern Brazilian coastal drainage system rather than the Amazonian or Paraná basins that hold most Rineloricaria diversity. The type locality is a shallow (under 3 ft deep), sandy river reach that the describing authors documented as already showing early-stage siltation at the time of collection.
Specific water-chemistry data for the site were not reported in the sources consulted. Like other Rineloricaria, the species is presumed to be a freshwater, bottom-associated (demersal) fish of flowing water, and the genus is noted for facultative air-breathing, supplementing gill respiration by gulping air at the surface under low-oxygen conditions — though this has not been directly observed in R. harenae.
Feeding
No dedicated dietary study has been published for Rineloricaria harenae. Members of the genus generally graze biofilm, algae, microorganisms and fine organic detritus from submerged surfaces using the rasping sucker mouth, and a similar diet can be presumed for R. harenae on genus-level grounds, but no species-specific observation exists.
Mating
No courtship or mating behaviour has been documented for Rineloricaria harenae. Whiptail catfishes in this genus are generally cave- or crevice-spawners in which the male takes a leading role in site selection and brood care, but nothing has been observed or reported specific to this species.
Breeding
There is no published breeding report for Rineloricaria harenae, in the wild or in captivity — the species was described in 2026 from a single sampling site and has no aquarium history. Many Rineloricaria are bred in the aquarium hobby as substrate egg-layers with paternal care, the male guarding and fanning a clutch deposited in a tube or crevice, but whether R. harenae follows this pattern is unknown.
In the aquarium
Rineloricaria harenae is not in the aquarium trade; it was described from scientific collections at a single Brazilian site only shortly before this account was written, and it carries no L-number or hobbyist husbandry record. In general terms, whiptail catfishes of comparable size are kept in well-filtered tanks with a soft sand substrate — fitting, given this species' own sand-dwelling habitat — gentle to moderate current, driftwood and refuges, and stable subtropical-to-tropical temperatures. Because nothing species-specific has been recorded, and its only known population lives in a single, already-silting river reach, prospective keepers should treat any claimed availability with scepticism and rely on general Rineloricaria care principles rather than experience with this fish.
Conservation
Rineloricaria harenae has not yet been formally assessed by the IUCN Red List; it was described in 2026. The describing authors report that the species is currently known only from its type locality, a shallow sandy reach already showing early-stage siltation, and they explicitly flag this as a sign of potential vulnerability and a conservation concern for low-order sandy habitats in the Eastern Brazilian coastal drainages generally. This is the describing authors' own observation rather than a formal Red List determination, and no extent-of-occurrence estimate or explicit threat-category recommendation was reported in the sources consulted.