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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 variola is distinguished from R. acuen, R. bockmanni, R. chromodontus, R. dani, R. dinizae, R. hera, R. jumaorum, R. pentakelis, R. marginalis n. sp., and R. loxochelis n. sp. 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. hardmanni 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 triangular dark spot on the anterior portion of the dorsal-fin membrane (vs. dorsal-fin spot absent); a Y-shaped light mark from snout tip to nostrils (vs. Y-shaped light mark absent); and a larger orbit, 27.1–31.0% snout length (vs. orbit 18.9–24.6% snout length). Rhinotocinclus variola is distinguished from R. britskii, R. discolor n. sp., R. eppleyi, R. isabelae n. sp., R. kwarup, R. longirostris, R. pilosus n. sp., and R. yaka by having dark dots smaller than a pupil diameter broadly distributed dorsally and ventrally on body (vs. dark dots absent, but sometimes darkened sensory pores may be present on head); a triangular dark spot on anterior portion of the pectoral-fin membrane (vs. dark spot absent); and, except for R. isabelae n. sp., the triangular dark spot of the dorsal fin occupying more than half of the fin (vs. dark spot occupying less than half of dorsal fin) (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. The specific name variola: meaning smallpox, spotted, in allusion to the dark dots that cover all dorsal and ventral body surfaces. A noun in apposition. Remarks: Most online searches at the moment (2022) will still give you the old genus name of Parotocinclus variola.

Smallpox Oto

Parotocinclus variola

Loricariidae

South America: Quebrada Tacana, a tributary to the Amazon River in Colombia. Type Locality: Colombia, Departamento Amazonas, Leticia, Quebrada Tacana, tributary to rio Amazonas at km 6.5 of road from Leticia to Tarapacá, 04°09’15”S 69°56’09”W.

3.0cm. (1¼s)

23-26°c (73-79°f.)

6.5-7.2.

Froese, R. and D. Pauly. Editors. 2022. FishBase. World Wide Web electronic publication. www.fishbase.org, ( 08/2022 ).
Lehmann, A.P., L.J. Schvambach and R.E. Reis, 2015. A new species of the armored catfish Parotocinclus (Loricariidae: Hypoptopomatinae), from the Amazon basin in Colombia. Neotrop. Ichthyol. 13(1):47-52.
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.