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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 pentakelis is distinguished from all congeners, except for R. bockmanni, R. dani, R. hera, R. marginalis n. sp., and R. loxochelis n. sp. by having the dominant colour pattern formed by dark bars on body well separated and distinct (vs. dominant colour pattern formed by wide dark bars partially coalesced or closed together, or formed by a dark stripe from the snout tip, through the eye and extending to end of caudal peduncle); having two separate light lines from snout tip diverging to each nostril (vs. light lines on snout absent, Y- or V-shaped); and by having teeth with yellow cusps (cusps light ochre or brown). Rhinotocinclus pentakelis is further distinguished from R. britskii, R. discolor, R. eppleyi, R. isabelae, R. kwarup, R. longirostris, R. pilosus, R. polyochrus, R. variola, and R. yaka by lacking an adipose fin (vs. adipose fin present). Rhinotocinclus pentakelis is further distinguished from congeners, except R. bockmanni, R. dani, R. loxochelis n. sp., and R. marginalis n. sp., by having small platelets at adipose-fin position (vs. small platelets absent). Rhinotocinclus pentakelis is distinguished from R. bockmanni by lacking a triangular dark spot at the dorsal-fin membrane (vs. dorsal-fin dark spot present), and by having a conspicuous dark bar 2 on body (vs. bar 2 absent or inconspicuous). It is distinguished from R. hera by having small platelets at adipose-fin position (vs. small platelets absent) and yellow teeth cusps (vs. light ochre cusps); and from R. dani by the deeper body (body depth 18.4–20.8% vs. 16.3–18.3% SL; caudal peduncle depth 10.1–11.7% vs. 8.8–9.9% SL; head depth 43.6–49.5% vs. 38.0–43.5% HL), and longer dorsal-fin spine (27.0–30.8% vs. 24.0–27.0% SL). Rhinotocinclus pentakelis is further distinguished from R. loxochelis n. sp. by the regularly arranged dark bars on body (vs. dark bars on body somewhat fragmented and inclined, such that they connect to form a zig-zag pattern), and the comparatively shorter head (head length 37.5–39.7% vs. 39.3–41.3% HL); and from R. marginalis n. sp. by the comparatively deeper caudal peduncle (10.1–11.7% vs. 9.1–10.1% SL and 26.3–29.7%; vs. 23.3–26.3% HL) (Reis & Lehmann 2022). Etymology: Rhinotocinclus masc., from the Greek (Rhinos), beak, snout and Otocinclus, a genus of Hypoptopomatinae, in allusion to the conspicuous and elegant snout of most of its species. Remarks: Most online searches at the moment (2022) will still give you the old genus name of Parotocinclus pentakelis.

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Parotocinclus pentakelis

Loricariidae

South America: Tocantins River basin, Tocantins, Brazil. Type locality: Brazil, Tocantins State, municipality Lavandeira, Rio Palmas, Rio Tocantins basin; 12°48’05”S 46°28’38”W.

2.5cm. (1ins)

24-27°c (75-81°f.)

5.5-6.5.

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.