Rhinotocinclus variola ( Lehmann, Schvambach & Reis, 2015 ), 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 : 36-38

Rhinotocinclus variola ( Lehmann, Schvambach & Reis, 2015) , new combination

( Figs. 22–23 ; Tab. 4 )

Parotocinclus variola Lehmann, Schvambach & Reis, 2015:47 (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. Holotype: ICNMHN 18685).

Diagnosis. 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 (Figs. 7A,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, 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., R. variola , 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 ( Fig. 13B ; 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 (Fig. 8C; vs. dark spot occupying less than half of dorsal fin).

Geographical distribution. Rhinotocinclus variola is known from the type-locality in the Quebrada Tacana, a creek tributary to the Amazon in Leticia, Departamento Amazonas, Colombia and the rio Urucu, an Amazon tributary in the state of Amazonas, Brazil ( Fig. 15 ). Rhinotocinclus variola is probably more widespread in creeks tributaries to the rio Amazonas in the western Amazon, in Brazil, Colombia, and Peru.

Remarks. This species was so far known from its type-locality in the Quebrada Tacana near Leticia, Colombia. We herein report the presence of R. variola for the first time in Brazil, in creeks tributary to the rio Urucu, a right margin tributary to the Amazon between the rio Juruá and the rio Purus. Rhinotocinclus variola was tentatively categorized as Least Concern (LC) by Lehmann et al. (2015) in the original description.

Material examined. Rio Amazonas basin: Colombia: ICNMHN 18685 , holotype , ICNMHN 10114 , 5 paratypes + 1 juv , ICNMHN 10326 , 3 paratypes, ICNMHN 10349 , 10 paratypes, MCP 48244 , 5 paratypes (5 measured), MCP 48245 , 4 (4 measured) + 2 cs + 1 juv paratypes, Quebrada Tacana, tributary to Río Amazonas at km 6.5 of road from Leticia to Tarapacá , Leticia, Departamento Amazonas, 04°09’15”S 69°56’09”W . Brazil, Amazonas State: MPEG 12260 , 1, igarapé Tartaruga , rio Urucu basin, Coari , Amazonas, 04º53’55.32”S 65º19’18.40”W. MPEG 12341, 6 (2 measured), igarapé Tartaruga, rio Urucu basin, Coari, 04º53’55.32”S 65º19’18.40”W. MPEG 12420, 6 (3 measured), igarapé IMT, rio Urucu basin, Coari, approx. 04º49’28”S 65º01’50”W . MPEG 12563, 6 of 11 (4 measured), igarapé IMT, rio Urucu basin, Coari, approx. 04º49’28”S 65º01’50”W.

Figures

FIGURE 13 | Pectoral-fin color pattern in Rhinotocinclus. A. R. longirostris, INPA 25483, mostly hyaline; B. R. variola, MCP 48245, triangular dark spot at base of branched rays. Scale bar = 2 mm.

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 22 | Rhinotocinclus variola, paratype, MCP 48245, 24.3 mm SL, male, Quebrada Tacana, tributary to Río Amazonas at km 6.5 of road from Leticia to Tarapacá, Leticia, Departamento Amazonas, Colombia.

FIGURE 23 | Rhinotocinclus variola, MPEG 12341, 20.2 mm SL, female, rio Coari, Coari, Amazonas, Brazil.