Taxonomy & naming
Farlowella odontotumulus was described in 1997 by Retzer and Page, the pair responsible for the most substantial modern revisionary work on the genus. The Catalog of Fishes (Eschmeyer, CAS) treats Farlowella odontotumulus as the valid combination, within genus Farlowella, subfamily Loricariinae, family Loricariidae.
Farlowella is the elongate 'twig catfish' genus of the Loricariinae, its members instantly recognisable for resembling submerged sticks. The genus name honours the Harvard botanist William Gilson Farlow. The epithet odontotumulus combines Greek and Latin roots referring to a tooth and a mound or raised swelling, pointing to a diagnostic dental or odontode feature used to separate the species from its many congeners — distinctions in this genus typically hinge on such fine morphological details.
Morphology
Farlowella odontotumulus reaches a maximum recorded length of about 7 in standard length. It shows the genus's defining body plan: a greatly elongated, near-cylindrical trunk, a long drawn-out snout, and a slender tapering tail, all sheathed in rows of bony plates. Brownish, mottled colouration breaks up the outline and reinforces the stick-like camouflage.
The epithet odontotumulus signals a distinctive tooth or odontode feature, but beyond that diagnostic the published morphological detail accessible here is limited. As with other Farlowella, the species is a facultative air-breather. Species-specific sexual dimorphism has not been documented; in the genus, breeding males typically develop enlarged odontodes on the snout.
Habitat
The species is recorded from two disjunct areas: the Aguarico River basin in Ecuador and the Mavaca River basin in Venezuela. The waters are freshwater, demersal and tropical. Twig catfishes generally inhabit flowing waters with submerged wood, root masses and leaf litter, where they cling to branches and stones.
No finely resolved water-chemistry or depth data for F. odontotumulus has been published beyond the general tropical, freshwater characterisation of its known basins.
Feeding
Farlowella odontotumulus is an algae and detritus grazer, with a low trophic level of around 2.5 typical of the genus. It rasps biofilm — algae, diatoms and associated micro-organisms — from submerged surfaces using its fine ventral dentition.
No species-specific feeding study has been published. Like its congeners, it would require constant access to algae and biofilm to thrive, a demand that makes the genus difficult to sustain outside richly mature systems.
Mating
No mating behaviour has been documented for Farlowella odontotumulus. Across the genus, courtship centres on a male-prepared flat surface onto which the female deposits adhesive eggs.
Breeding
Breeding has not been reported for Farlowella odontotumulus. In the genus generally, Farlowella are open substrate-spawners with paternal care, the male guarding and fanning a clutch laid on a smooth surface until hatching. No clutch-size or developmental data exists for this species.
In the aquarium
Farlowella odontotumulus is not a routinely traded aquarium fish, and no established captive husbandry record for it is available. Twig catfishes in general are demanding aquarium subjects requiring pristine, oxygen-rich water, abundant natural algae and biofilm, gentle to moderate flow, and driftwood cover; they are peaceful and readily out-competed at feeding time.
Given the lack of population data and husbandry experience, F. odontotumulus is best treated as a fish of scientific interest rather than a hobby subject.
Conservation
The IUCN Red List assessed Farlowella odontotumulus as Data Deficient on 21 August 2020. A Data Deficient listing means there is insufficient information on the species' distribution, abundance and trends to assign a meaningful threat category — it is not a statement of safety, only of uncertainty.
The species' known occurrence across two separate basins, in Ecuador and Venezuela, suggests a wider potential range than some of its more narrowly endemic congeners, but the underlying survey data is too thin to draw conclusions. Targeted field surveys would be needed to clarify whether the species is genuinely widespread or simply under-sampled. CITES has not evaluated the species.