Taxonomy & naming
The species was first described by Henry Weed Fowler in 1941 under the name Plecostomus iheringi; the following year, in 1942, Fowler renamed it Plecostomus gomesi because the earlier epithet was preoccupied by P. iheringii. The 1942 name gomesi is therefore the valid original combination. Over subsequent decades the species passed through several generic placements — Squaliforma, then Hypostomus — before Ray and Armbruster (2016), in a revision published in Zootaxa 4072, transferred it to the genus Aphanotorulus, which they reconstituted to hold six valid species: A. ammophilus, A. emarginatus, A. gomesi, A. horridus, A. phrixosoma, and A. unicolor.
The parenthetical authority notation — (Fowler, 1942) — reflects this generic transfer: the species was not originally placed in Aphanotorulus. The Catalog of Fishes (Eschmeyer, CAS) treats Aphanotorulus gomesi (Fowler, 1942) as the valid combination. The species is placed in subfamily Hypostominae of Loricariidae, within the H. emarginatus species group.
The holotype is ANSP 69409, housed at the Academy of Natural Sciences of Philadelphia. No additional specimens have been collected and matched to this taxon in the published literature.
Morphology
Descriptive data on Aphanotorulus gomesi are limited to what can be gathered from the holotype. FishBase records a maximum size of 5.5 in SL, consistent with a medium-small loricariid. The suedamerikafans.de database references a total length of approximately 8 in for this species, which is broadly consistent with the SL figure when a loricariid SL-to-TL conversion of roughly 1.3–1.4× is applied.
The lateral line bears 29 plates, and 8 plates run along the dorsal-fin base — proportions recorded in the original description. The head is moderately compressed, without a strongly elevated supraoccipital crest. The pectoral fin extends past the pelvic-fin insertion. Sexual dimorphism in the genus is expressed as stronger odontode development on the pectoral fins and posterior body in males, consistent with the general Hypostominae pattern.
Beyond these measurements from the type specimen, no additional morphological data specific to this species appear in the published literature.
Habitat
The holotype of Aphanotorulus gomesi was collected from the Rio Jaguaribe, Ceará state, north-eastern Brazil. The Jaguaribe is an intermittent river of the semi-arid Caatinga biome, draining a large basin (approximately 75,0 mi²) that discharges to the Atlantic coast near the city of Aracati. Unlike the permanently flowing tributaries of the Amazon or Paraná systems, the Rio Jaguaribe is subject to seasonal drought — portions of the river run dry or nearly dry during the extended dry season typical of north-eastern Brazil.
No ecological data — water temperature, pH, substrate type, or microhabitat description — are available for this species from the collection site or from any subsequent field survey. Data sparse.
Feeding
No dietary information is available for Aphanotorulus gomesi. FishBase classifies the species as a demersal, freshwater fish with facultative air-breathing capability — a feature shared by several Hypostominae of the semi-arid drainage systems of north-eastern Brazil, where dissolved oxygen levels can fall dramatically during low-water periods.
By analogy with close relatives in the H. emarginatus group and with other Hypostominae of similar body form, the species is assumed to be a periphyton scraper and detritivore, grazing algal films and organic material from rock and substrate surfaces. Data sparse.
Mating
No information on mating behaviour in Aphanotorulus gomesi is available. The species has never been maintained in captivity to the author's knowledge, and no field observations have been reported beyond the original collection event. Data sparse.
Breeding
No breeding data are available. Data sparse.
In the aquarium
Aphanotorulus gomesi is not known to be in the ornamental fish trade. The Rio Jaguaribe in Ceará is not an established collection region for the aquarium industry, and the species' Data Deficient IUCN status — based on its being known from a single specimen — suggests it has not been encountered in quantity by collectors.
If encountered, general Hypostominae husbandry principles would apply: a well-aerated aquarium with smooth rock substrate, sinking algae-based foods, and water quality maintained with regular partial changes. The semi-arid Caatinga origin of the type locality suggests possible tolerance of warm, seasonally variable water, but no precise parameters can be recommended from available data.
Conservation
The IUCN Red List assessed Aphanotorulus gomesi as Data Deficient (DD) in November 2018, citing the fundamental limitation that the species is known only from the holotype. Without additional specimens and population data, any estimate of population size, trend, or extinction risk is impossible.
The Rio Jaguaribe drainage faces significant anthropogenic pressure. North-eastern Brazil is heavily affected by dam construction (the Orós and Castanhão reservoirs are both within the Jaguaribe basin), agricultural water extraction, and desertification dynamics exacerbated by climate change. Whether A. gomesi persists in the river today, and in what numbers, is unknown. The species exemplifies the category of freshwater fish whose conservation status cannot be meaningfully evaluated until additional field surveys are conducted in the basin.