Taxonomy & naming
Pareiorhaphis proskynita was described by Pereira and Britto in 2012, in Copeia (2012, number 3, pages 519–526). The Catalog of Fishes (Eschmeyer, CAS) recognises it as valid (genus id 34, species id 72432).
The genus Pareiorhaphis is a member of the subfamily Neoplecostominae, a group of small armoured catfishes of south-eastern and southern Brazilian streams. FishBase files the genus under Hypoptopomatinae, but the describing authors and the modern literature place Pareiorhaphis among the neoplecostomines, which is followed here.
The specific epithet proskynita derives from the Greek word for 'pilgrim', alluding to the pilgrimage made by visitors to the Santuário do Caraça, the locality where the species was found.
Morphology
Pareiorhaphis proskynita reaches about 4 in in standard length (maximum recorded, male or unsexed). The dorsal fin bears 8 soft rays and the anal fin 6. The species is most readily recognised by its colour pattern: large, conspicuous dark-brown blotches scattered irregularly over a yellowish-tan background across the head, dorsal surface, and flanks. The adipose fin is usually absent. As in the rest of the genus, the body is elongated and armoured with overlapping bony scutes.
Habitat
The species occupies the upper portion of the Ribeirão Caraça, a tributary of the Rio Piracicaba in the upper Rio Doce basin, Minas Gerais, Brazil. These are blackwater tributaries with translucent, fast-flowing water running over very large rocks sparsely strewn with iron-ore pebbles and gravel — a reflection of the region's mineral-rich geology. The rocks are coated with a thin layer of periphyton and green algae.
The fish inhabit medium-sized streams roughly 2–5 ft deep, with juveniles concentrating in slow-current stretches among loose stones. Recorded pH is markedly acidic, between 4.5 and 5.5. The species is described as tropical and demersal, and the genus is noted for facultative air-breathing.
Feeding
Gut-content analysis of two specimens (1.5–3.5 in SL) showed the diet to consist mainly of filamentous algae. This is consistent with the species' habit of grazing the periphyton and algal film coating the large rocks of its fast-flowing streams.
Mating
No data on courtship or mating behaviour have been published for this species.
Breeding
No breeding data are available for Pareiorhaphis proskynita.
In the aquarium
Pareiorhaphis proskynita is not a species of the ornamental trade and no aquarium-keeping experience is documented. Its known environment — cool, fast, highly oxygenated and notably acidic (pH 4.5–5.5) upland stream water over rock — would make it a specialist biotope subject rather than a community fish. No captive-care parameters have been published.
Conservation
The IUCN Red List assessed Pareiorhaphis proskynita as Least Concern, with the assessment dated 7 November 2018. The species has a restricted range in the upper Rio Doce basin but is not presently regarded as threatened. The upper Rio Doce drainage has historically faced pressures from mining activity in the iron-rich Minas Gerais region, which remains the principal long-term concern for narrowly distributed stream fishes there.