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Reis & Lehmann 2022 (3)

A new genus has been erected, Rhinotocinclus, (2022) with the type species of Parotocinclus longirostris Garavello, 1988. Abstract: A new genus of Hypopopomatinae armored catfish is described from the northern portions of South America, namely the Amazon, Orinoco and Guianan coastal drainages. The new genus is diagnosed from all remaining hypoptopomatines by having the canal cheek plate on the ventral surface of the head posteriorly elongated and contacting the cleithrum, in addition to other features that distinguish the new genus from specific genera. Five new species are described and 18 species currently allocated in Parotocinclus, Hisonotus, and Curculionichthys are transferred to the new genus and rediagnosed. Parotocinclus amazonensis and P. aripuanensis are considered junior synonyms of P. britskii. The secondary sexual dimorphism of the members of the new genus is detailed and illustrated. Morphological characters are used to delimit four phenotypic groups of species that might have phylogenetic significance, which still have to be properly tested. A key to the species is offered and diagnoses, illustrations, and distribution maps are provided for all species (Reis & Lehmann 2022). Description: Rhinotocinclus discolor is distinguished from R. acuen, R. bockmanni, R. chromodontus, R. dani, R. dinizae, R. hera, R. jumaorum, R. loxochelis n. sp., R. pentakelis, and R. marginalis n. sp. and by possessing an adipose fin (vs. adipose fin absent), and by having a Y-shaped light mark from the snout tip to each nostril (vs. light mark V-shaped or present as two separate lines from snout tip diverging to each nostril). It is distinguished from R. collinsae, R. halbolthi, and R. hardmani by lacking accessory teeth on both premaxilla and dentary (vs. accessory teeth present ); the odontodes on the ventral surface of first pelvic-fin ray bent and pointing mesially (vs. odontodes aligned with main ray axis ); a Y-shaped light mark from snout tip to nostrils (vs. Y-shaped light mark absent); and a larger orbit, 29.8–36.2% snout length (vs. orbit 18.9–24.6% snout length). Rhinotocinclus discolor is distinguished from R. britskii, R. eppleyi, R. kwarup, R. isabelae n. sp., R. longirostris, R. pilosus n. sp., R. polyochrus, R. variola, and R. yaka by having a small, inconspicuous triangular spot at the dorsal-fin base (vs. spot large and conspicuous). It is further distinguished by having the dark transverse bar 2+3 fused together (vs. bars not fused in R. britskii, R. eppleyi, R. kwarup, and R. longirostris, or bars 1+2 fused in R. isabelae n. sp., R. pilosus n. sp., R. polyochrus, R. variola, and R. yaka) (Reis & Lehmann 2022). Etymology: Rhinotocinclus masc., from the Greek ????s (Rhinos), beak, snout and Otocinclus, a genus of Hypoptopomatinae, in allusion to the conspicuous and elegant snout of most of its species. Rhinotocinclus discolor, from the Latin color, color, and the prefix dis-, meaning not of the same color, in allusion to the remarkable color pattern with the second and third dark bars coalesced. A noun in apposition (Reis & Lehmann 2022).

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Loricariidae

Soth America: From Caño Pasa, tributary of Río Sipapo, 98 km from Puerto Ayacucho airport, Amazonas, Venezuela.

2.5cm. (1ins)

22-26°c (71-79°f.)

6.5-7.2.

Reis RE, Lehmann A. P. A new genus of armored catfish (Siluriformes: Loricariidae) from the Greater Amazon, with a review of the species and description of five new species. Neotrop Ichthyol. 2022.