Taxonomy & naming
Harttia uatumensis was described by Lúcia Rapp Py-Daniel and Efrem Ferreira de Oliveira in 2001, in a paper presenting seven new species of Harttia from the Amazonian-Guyana region (Ichthyological Exploration of Freshwaters 12(1): 79–96). The Catalog of Fishes (Eschmeyer, CAS) recognises the name as valid (species id 66297, genus id 3899).
The genus Harttia belongs to the subfamily Loricariinae — the slender, flattened 'whiptail' loricariids characterised by a depressed body and a long, tapering caudal peduncle. The species epithet refers directly to the type locality, the rio Uatumã, from which the species takes its name.
No synonyms or alternative combinations are in circulation; the species has been treated consistently as Harttia uatumensis since its description. It carries no L-number, having entered the literature through formal taxonomy rather than the aquarium trade.
Morphology
Harttia uatumensis reaches at least 4.5 in in standard length (the largest measured specimen in the type series). The body and head are broad and strongly flattened, lacking the dorsal keels or elevations seen in some relatives. The head is triangular in outline, with a slightly prominent, naked snout tip and smooth head plates that bear no bristles. The eyes are large, set in a near-quadrangular orbit, and the supraoccipital is flat.
Colour pattern is distinctive: the head carries light-brown blotches over a dark-brown ground, and the body shows five broad transverse dark bars across the trunk and caudal peduncle. The last of these bars is very dark and surrounds the insertion of the caudal fin.
The mouth is large with a thick upper lip. The rictal barbels are extremely reduced, attached to the lower lip by a well-developed, non-papillate membrane. A large, triangular subpreopercle is partly covered by odontodes. The abdominal cover is incomplete, and there are 29–30 lateral plates, carinate (keeled) and arranged in two confluent series.
No data on sexual dimorphism has been published for this species; many Loricariinae males develop elongated odontodes or expanded fin elements during breeding, but this has not been documented for H. uatumensis.
Habitat
The species is endemic to the rio Uatumã basin in Brazil, a left-bank tributary of the Amazon in Amazonas state. It is a freshwater, benthopelagic fish of tropical lowland rivers.
No detailed in-situ measurements of temperature, pH, or conductivity have been published for the species. As a member of the flattened Loricariinae, it is associated with the bottom and is adapted to clinging to firm substrate; the broad, depressed body of Harttia is typical of fishes occupying flowing, well-oxygenated stretches over rock or sand. Beyond the basin-level distribution, microhabitat specifics for H. uatumensis remain undocumented.
Feeding
No direct dietary study of Harttia uatumensis has been published. FishBase lists an estimated trophic level of 2.6, consistent with a diet weighted toward algae, biofilm, and small benthic invertebrates rather than higher-trophic prey.
Like other Loricariinae, the species is presumed to graze the aufwuchs (algal and microbial film) and associated micro-invertebrates from hard surfaces using its ventral mouth. Specific gut-content or feeding-behaviour data is not available.
Mating
No data on courtship or mating behaviour has been published for Harttia uatumensis. Within the genus and the wider Loricariinae, reproduction commonly involves substrate spawning with parental egg-guarding, but no observations specific to this species have been reported.
Breeding
No breeding records exist for Harttia uatumensis, in the wild or in captivity. Several Harttia species are known to be substrate spawners in which the male guards an adhesive egg clutch, but neither clutch size, spawning site, nor parental-care details have been documented for this species. The species is not known in the aquarium hobby, so no captive-spawning reports are available.
In the aquarium
Harttia uatumensis is essentially absent from the ornamental trade and has no established aquarium husbandry record. No species-specific captive parameters, tankmate guidance, or maintenance notes can be given without inventing them.
By analogy with other flattened Loricariinae, fishes of this body type generally require well-oxygenated water, gentle to moderate current, and a substrate of sand or smooth rock over which they can rest and graze. These are general inferences for the body plan, not documented requirements for this species.
Conservation
The IUCN Red List assessed Harttia uatumensis as Near Threatened (NT) under criterion B1b(iii), with the assessment dated 7 November 2018. The listing reflects the species' restriction to the single rio Uatumã basin and an inferred continuing decline in the quality of its habitat.
The Uatumã is notable for the Balbina hydroelectric dam, whose reservoir flooded a large area of forest in the late 1980s and altered the river's flow, sediment, and water-chemistry regime downstream. For a basin-endemic, current-adapted bottom fish, such impoundment is the kind of habitat alteration that drives the 'continuing decline in habitat quality' element of the NT assessment. With no evidence of populations outside the Uatumã, the species' conservation status is tied closely to the condition of that one basin.