Taxonomy & naming
Pareiorhaphis lophia was described by Edson H. L. Pereira and Angela M. Zanata in 2014, in Neotropical Ichthyology (volume 12, number 1, pages 35–42), from the rio Paraguaçu basin in Bahia State, northeastern Brazil. The Catalog of Fishes (Eschmeyer, CAS) recognises it as a valid species (spid 73246).
The genus Pareiorhaphis was erected by Miranda Ribeiro in 1918 and resurrected by Pereira in 2005; it belongs to the subfamily Neoplecostominae, one of the smaller and more basal lineages within the Loricariidae. (FishBase lists the subfamily as Hypoptopomatinae in its header, but this is a known cataloguing artefact — Pareiorhaphis is a neoplecostomine genus, as confirmed in the original descriptions.)
The specific epithet lophia derives from the Greek for crest or ridge, referring to the distinct bump on the lower lip that diagnoses the species.
Morphology
Pareiorhaphis lophia reaches at least 3 in standard length (SL) in the known material. Like other members of the genus, it is a modestly sized loricariid with the family's characteristic armour of overlapping bony scutes and a ventral suckermouth.
The diagnostic feature is a distinct crest or bump on the lower lip, from which the species takes its name. Fin counts recorded in the original description are a dorsal fin of one spine and seven branched rays (D I/7) and an anal fin of six rays (A 6); the species has 28 vertebrae.
Detailed sexual dimorphism for this species is not described in the cached material. Across Pareiorhaphis, mature males typically develop hypertrophied odontodes along the head and pectoral-fin spines, but no species-specific account is published here.
Habitat
The species is known from the rio Paraguaçu basin, a coastal drainage in Bahia State, northeastern Brazil. It inhabits blackwater river conditions — freshwater, demersal, and tropical.
Field observations place P. lophia on shallow rocky platforms and inside crevices, where it shelters at night, and among pebbles on shallow rapids. It has also been collected on narrow stretches roughly 19.5 in deep just below a waterfall, in fast current over a rocky bottom. At its collection sites it occurs alongside (syntopic with) the larger loricariids Hypostomus chrysostiktos and Hypostomus jaguar.
Like other Pareiorhaphis, it is a facultative air-breather, a trait that suits life in warm, well-oxygenated but seasonally variable rocky streams.
Feeding
No diet study for Pareiorhaphis lophia is published in the cached sources. Its ventral suckermouth, rocky-rapids microhabitat, and grazing among pebbles and crevices are consistent with the loricariid pattern of rasping biofilm — algae, diatoms, and associated micro-organisms — from hard surfaces, but the specific gut contents have not been reported here. No firm dietary claim can be made beyond this general inference.
Mating
No data on courtship or mating behaviour has been published for Pareiorhaphis lophia. The genus is not known to be bred in the aquarium, and no reproductive observations appear in the cached sources.
Breeding
No breeding account for Pareiorhaphis lophia exists in the available literature. Loricariids generally lay adhesive eggs guarded by the male, and many neoplecostomines spawn in rock crevices, but no spawning mode, clutch size, or parental-care detail has been documented for this species. Stating otherwise would be speculation.
In the aquarium
Pareiorhaphis lophia is essentially absent from the aquarium hobby; it carries no L-number and is not traded. No husbandry experience has been published.
Any inferences about care would have to be drawn from its wild habitat: warm, fast-flowing, well-oxygenated blackwater over a rocky bottom, with abundant crevices and pebble cover for shelter. As with related rheophilic loricariids, strong current, high oxygen, clean water, and a rocky aquascape would be the logical starting points — but these are extrapolations, not tested recommendations.
Conservation
The IUCN Red List assessed Pareiorhaphis lophia as Least Concern (LC), assessed 7 November 2018. It is not evaluated under CITES, and FishBase rates its resilience as high.
The species is restricted to the rio Paraguaçu basin in Bahia, so while it is not currently considered threatened, its narrow distribution means localised pressures on coastal northeastern Brazilian rivers — such as water abstraction, sedimentation, and damming — would warrant monitoring of the populations there.