Taxonomy & naming
Limatulichthys nasarcus was described by Alejandro Londoño-Burbano, Sandra Lefebvre, and Nathan Lujan in 2014, in Zootaxa (volume 3884, number 4, pages 360–370), as a new species from the western Guiana Shield. It belongs to the subfamily Loricariinae of the armoured catfish family Loricariidae. The Catalog of Fishes (Eschmeyer, CAS) records it under species id 73526 and genus id 8180.
The genus Limatulichthys is a small group of slender loricariins, of which L. nasarcus is distinguished from the type species L. griseus by a suite of characters detailed in the original description: anterior abdominal plates about half the size of the central plates, dorsal spotting that extends across the entire dorsum including the snout and head with spots less than half the naris diameter, a broadly rounded snout in dorsal view (versus the acutely triangular snout of L. griseus), a longer head (21.4–24.2% of standard length versus 17.7–21.0%), and a longer anal fin.
Morphology
Limatulichthys nasarcus reaches a maximum recorded size of about 6 in standard length (Ref. 97714). The body is the elongate, depressed form characteristic of the Loricariinae. Meristic counts from the description are a dorsal fin of 1 spine and 7 soft rays (D I,7) and an anal fin of 1 spine and 5 soft rays (A I,5).
The most diagnostic external feature is the broadly rounded snout when viewed from above — directly contrasting the acutely triangular snout of the related L. griseus and the source of the species epithet. Fine spotting covers the entire dorsum, extending onto the snout and head, with each spot less than half the diameter of the naris. The head is proportionally long (21.4–24.2% SL), and the anal fin is longer than in its congener.
Habitat
Limatulichthys nasarcus is recorded from the middle Ventuari and lower Caura rivers, within the Orinoco River drainage of Venezuela, on the western Guiana Shield. FishBase characterises it as a freshwater, demersal species of tropical waters. Beyond this general distribution, detailed microhabitat data is sparse in the published record.
Feeding
No dietary study of Limatulichthys nasarcus has been published; the cache notes the diet data as sparse. Members of the Loricariinae are generally bottom-dwelling grazers that rasp biofilm, algae, and fine detritus from submerged surfaces, and L. nasarcus is presumed to follow this pattern, but no direct feeding observations are available to confirm specifics.
Mating
No data on the courtship or mating behaviour of Limatulichthys nasarcus has been published.
Breeding
No reproductive data for Limatulichthys nasarcus has been published — spawning mode, clutch size, and parental care are all undescribed for the species.
In the aquarium
Limatulichthys nasarcus has essentially no presence in the aquarium hobby, and no husbandry information has been published. As a Guiana Shield river species of the Orinoco drainage, it would be expected to require clean, warm, well-oxygenated water, but in the absence of any documented experience these are inferences rather than tested recommendations.
Conservation
The IUCN Red List assessed Limatulichthys nasarcus as Data Deficient (DD) on 21 August 2020 — meaning there is insufficient information on its distribution, population, and threats to make a reliable assessment of its extinction risk. As a recently described species (2014) known from the middle Ventuari and lower Caura rivers, it remains poorly studied, and further fieldwork would be needed to clarify its status. The broader Orinoco drainage of the Guiana Shield faces pressures from mining and habitat alteration, but no species-specific threat data has been documented.