Taxonomy & naming
Lithogenes wahari was described by Scott A. Schaefer and Francisco Provenzano in 2008, in their monographic treatment of the subfamily Lithogeninae (American Museum Novitates 3637: 1–49). That paper revised the anatomy and interrelationships of the group and erected this species, collected from the Río Cuao in the Orinoco drainage of Venezuela. The Catalog of Fishes (Eschmeyer, CAS) recognises Lithogenes wahari as a valid name.
The genus Lithogenes anchors the subfamily Lithogeninae, regarded as the basal-most, relict lineage of the family Loricariidae. Where the higher plecos evolved the familiar ventral oral disc for clinging and grazing, lithogenines retain a more primitive arrangement and grip the substrate using a pelvic-fin sucker — a feature of considerable interest to those studying loricariid evolution. The diagnostic distinction between L. wahari and the closely related L. villosus rests in part on the pectoral-fin ray count (9 branched rays versus 8) and on small, irregular plates along the caudal peduncle.
The species epithet wahari honours Rua-Wahari, the creator god of the Piaroa people of Venezuela, and is treated as a noun in apposition.
Morphology
Lithogenes wahari is a small loricariid: the largest examined specimens reach about 3 in standard length (SL), with females recorded to roughly 2 in SL. Meristic counts from the original description give 6 dorsal soft rays, 6–7 anal soft rays, 9 branched pectoral-fin rays, and 12 premaxillary teeth whose cusps are asymmetrically bifid.
Several characters distinguish it from its congeners. It lacks odontodes on the proximal ventral surface of the first pelvic-fin ray and lacks accessory premaxillary teeth. The anal fin carries an intense band of pigment along its base together with a diffuse spot at midlength, and there is no ossified spine on the anterior edge of the adipose fin. From L. villosus it differs by the higher branched pectoral-ray count and the presence of small, irregular plates on the caudal peduncle.
The defining feature of the lineage — a pelvic fin modified into a grasping sucker for holding station on bedrock in fast current — sets these fish apart from the oral-disc plecos. No published account describes external sexual dimorphism in detail beyond the difference in maximum recorded body size between the sexes.
Habitat
The species is known from the Río Cuao in the Orinoco drainage of Venezuela, in South America. Its habitat is described as moderately high-gradient forest streams with clear to light-green water, swift current, and exposed bedrock substratum.
This is a rheophilic, rock-clinging fish adapted to turbulent, well-oxygenated flow over hard rock. The pelvic-fin sucker is the morphological key to that lifestyle, allowing the fish to maintain position against current on smooth bedrock surfaces where a less specialised body plan would be swept away. Beyond these notes from the type material and the formal description, detailed ecological data — seasonal range, depth, water chemistry — have not been published.
Feeding
No detailed feeding study has been published for Lithogenes wahari. As a small benthic loricariid of swift bedrock streams, it can reasonably be inferred to graze the biofilm — algae, microorganisms, and fine detritus — that coats rock surfaces in fast-flowing forest creeks, but the specific diet has not been documented. Its dentition (12 premaxillary teeth with asymmetrically bifid cusps) is consistent with a substrate-rasping habit rather than the wood-gouging spatulate teeth of the panaque clade.
Mating
No data on courtship or mating behaviour have been published for Lithogenes wahari. The species is not kept or bred in the aquarium hobby, and the original description focuses on anatomy and systematics rather than reproductive biology.
Breeding
No data on reproduction, spawning mode, clutch size, or parental care have been published for Lithogenes wahari. Nothing is recorded about its breeding in the wild, and there are no captive breeding accounts.
In the aquarium
Lithogenes wahari is not part of the aquarium hobby. It carries no L-number, is not imported for the ornamental trade, and there are no husbandry reports. A specialised rheophilic fish from high-gradient bedrock streams would in any case demand strong, well-oxygenated current and stable cool, clean water — conditions rarely replicated by general aquarists — but in practice the species is simply unavailable and undocumented in captivity.
Conservation
The IUCN Red List assessed Lithogenes wahari as Data Deficient (DD) on 25 May 2017, indicating that available information is insufficient to evaluate its risk of extinction. As a narrowly recorded, habitat-specialised fish known from a limited area of the Orinoco drainage, it would be sensitive to changes in stream flow, water clarity, and substrate — but no specific threats have been quantified, and its true range and population status remain poorly known.