Rhinotocinclus yaka ( Lehmann, Lima & Reis, 2018 ),, 2022

Reis, Roberto E. & Lehmann A., Pablo, 2022, A new genus of armored catfish (Siluriformes: Loricariidae) from the Greater Amazon, with a review of the species and description of five new species, Neotropical Ichthyology (e 220002) 20 (2), pp. 1-100 : 38-40

Rhinotocinclus yaka ( Lehmann, Lima & Reis, 2018), new combination

( Fig. 24 ; Tab. 4 )

Parotocinclus yaka Lehmann, Lima & Reis, 2018:586 (Type-locality: Brazil, Amazonas, Rio Tiquié drainage, Igarapé Açaí near São Pedro Village, approx. 00°16’N 69°58’W. Holotype: MZUSP 123655).

Diagnosis. Rhinotocinclus yaka 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 (Figs. 6A,B; 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 (Figs. 5B,C; vs. accessory teeth present, Fig. 5A); the odontodes on the ventral surface of first pelvic-fin ray bent and pointing mesially (Fig. 9A; vs. odontodes aligned with main ray axis, Fig. 9B); a triangular dark spot on the anterior portion of the dorsal-fin membrane (Fig. 8B; 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, 26.9–32.5% snout length (vs. orbit 18.9–24.6% snout length). Rhinotocinclus yaka is distinguished from R. britskii and R. kwarup , by having the snout more acutely pointed (Fig. 11B; vs. snout more broadly rounded, Fig. 11A); dark bars on body wider and closer together (Fig. 7B; vs. dark bars on body narrower and more widely spaced, Fig. 7A); and 2–3 plates between the posterior border of the rostral plate and the nostril (Fig. 12A; vs. one plate). Rhinotocinclus yaka is distinguished from R. eppleyi and R. longirostris by having 1–2 irregular series of middle abdominal plates (vs. 4–5 irregular series); and dark bars on body 1+2 fused (vs. five dark bars on body). It is distinguished from R. polyochrus , R. discolor n. sp., and R. isabelae n. sp. by having more numerous premaxillary teeth (34–39; vs. 23–32, 23–26 and 21–29 respectively). It is further distinguished from R. polyochrus and and R. isabelae n. sp. by its shallower body (body depth 14.0–17.2% SL; vs. 17.9–20.0% and 17.8–20.9% SL, respectively); and from R. discolor n. sp. by having the triangular dorsal-fin dark spot occupying nearly one third of the fin (vs. small dorsal-fin spot). Rhinotocinclus yaka is distinguished from P. variola by having the triangular dorsal-fin dark spot occupying nearly one third of the fin (Fig. 8B; vs. dorsal-fin spot occupying more than half of the dorsal fin, Fig. 8C), and by lacking dark dots smaller than a pupil diameter broadly distributed dorsally and ventrally on body (vs. dots present). Rhinotocinclus yaka is finally distinguished from R. pilosus n. sp. by having 1–2 irregular series of large middle abdominal plates between the lateral abdominal plates (Fig. 10B; vs. belly naked or with one series of granular plates in the middle, Fig. 10C), and by having 3–4 lateral abdominal plates (vs. 1–2 such plates).

Geographical distribution. Rhinotocinclus yaka occurs in the upper rio Tiquié, a tributary to the upper rio Negro, state of Amazonas, Brazil ( Fig. 15 ). Rhinotocinclus yaka is probably more widespread in the rio Tiquié and perhaps in the rio Uaupés basin, both in Brazil and Colombia.

Remarks. Rhinotocinclus yaka was tentatively categorized as Least Concern (LC) by Lehmann et al. (2018) in the original description.

Material examined. Rio Negro basin, Amazonas State, Brazil: MZUSP 123655 , holotype (measured), ANSP 206002 , 2 paratypes (1 measured), MCP 53639 , 5 (4 measured) + 2 cs paratypes , MZUSP 81408 , 20 paratypes (5 measured), ZUEC 17032 , 2 paratypes (1 measured), igarapé Açaí near São Pedro Village , rio Tiquié basin, approx. 00°16’N 69°58’W . MZUSP 85053 , 2 paratypes (2 measured), black water creek tributary to rio Tiquié near Fronteira Village , approx. 00°15’N 70°02’W . MZUSP 93308 , 2 paratypes, igarapé Cunuri (or Macucu), on opposite shore of São José II Village , rio Tiquié basin, approx. 00°13’N 69°36’W.

Figures

FIGURE 15 | Geographical distribution of Rhinotocinclus species of the R. britskii group in central and northwestern South America. Rhinotocinclus britskii (white dots); R. discolor n. sp. (purple dots); R. eppleyi (orange dots); R. isabelae n. sp. (pink dots); R. kwarup (red dots); R. longirostris (blue dots); R. pilosus n. sp. (yellow dots); R. polyochrus (cyan dot); R. variola (black dots); R. yaka (light green dots). T = Type-locality; T1 = type-locality of Parotocinclus britskii, T2 = type-locality of P. amazonensis, T3 = type-locality of P. aripuanensis.

FIGURE 24 | Rhinotocinclus yaka, holotype, MZUSP 123655, 29.4 mm SL, female, igarapé Açaí near São Pedro Village, rio Tiquié basin, Amazonas, Brazil.