Taxonomy & naming
Rineloricaria catamarcensis was described by Carlos Berg in 1895. It belongs to the family Loricariidae, subfamily Loricariinae — the whiptail catfishes, distinguished by their long, depressed bodies and elongated tail region. The species was later reviewed in the regional treatment by Ringuelet, Arámburu and Alonso de Arámburu (1967), a standard work on the freshwater fishes of Argentina.
The genus Rineloricaria is among the largest in the subfamily and has a long history of taxonomic shuffling; many of its species were at various times placed in related whiptail genera. FishBase recognises the valid combination Rineloricaria catamarcensis.
The species epithet 'catamarcensis' refers to Catamarca Province in north-western Argentina, the region from which the species was described.
Morphology
Rineloricaria catamarcensis reaches a maximum recorded length of about 4.5 in. Like other members of the genus it has the characteristic whiptail form: a long, slender, dorsally flattened body armoured in bony plates, tapering to a thin caudal region. The ventral suckermouth is adapted for grazing surfaces on the stream bed.
Detailed meristic and dimorphism data for this species are not given in the available sources. In Rineloricaria generally, breeding males develop odontodes (bristle-like dermal teeth) on the head and pectoral fins, but specific observations for R. catamarcensis are not published here.
Habitat
The species occurs in the Tala and Salí river basins in Catamarca (and the adjacent Tucumán region) of north-western Argentina. It is a freshwater, demersal (bottom-dwelling) fish, and notably a temperate-zone whiptail — one of the more southerly Rineloricaria, living outside the tropical core of the genus's range.
Members of the genus are facultative air-breathers, able to supplement gill respiration by gulping air at the surface, which helps them tolerate warm, low-oxygen conditions in shallow streams. No measured temperature, pH, or hardness values for this species' waters are published in the available sources.
Feeding
Rineloricaria catamarcensis is a bottom-grazer with a low trophic level of about 2.5, consistent with a diet dominated by algae (aufwuchs) and detritus rasped from the substrate. It uses its suckermouth to scrape biofilm and fine organic material from rocks, wood, and the stream bed. No detailed gut-content study for this species is published; the dietary picture follows from its trophic level and from the feeding habits typical of the genus.
Mating
No data on the courtship or mating behaviour of Rineloricaria catamarcensis has been published. Whiptail catfishes of this genus are generally substrate spawners in which males guard the eggs, but specific observations for this species are not available in the consulted sources.
Breeding
No breeding data specific to Rineloricaria catamarcensis exists in the available sources. Within Rineloricaria, the typical pattern is for eggs to be laid in a sheltered site — often a crevice, tube, or among submerged material — and guarded and fanned by the male until they hatch, but no clutch size, spawning site, or developmental data for this particular species has been documented.
In the aquarium
Rineloricaria catamarcensis is not a commonly kept aquarium fish, and no L-number has been assigned to it. There is little or no established hobby husbandry data specific to the species.
Because it is a temperate-zone fish, it would be expected to prefer cooler conditions than the tropical whiptails more familiar in the trade — an important consideration that should be treated as inference from its range rather than as documented aquarium practice. Any keeping recommendations would have to be reasoned from its natural habitat (cooler, flowing Argentine streams with a bottom of rock and detritus) rather than from a body of aquarium experience.
Conservation
The IUCN Red List assessed Rineloricaria catamarcensis as Least Concern (LC) on 8 November 2020. A Least Concern listing indicates the species is widespread or common enough that it does not currently qualify for a threatened category. It is not evaluated under CITES.
As with many small South American catfishes, the principal long-term concerns would be local — habitat alteration, water abstraction, and pollution in the Tala and Salí basins — but at present the species is not considered threatened.