Rhinotocinclus halbothi ( Lehmann, Lazzarotto & Reis, 2014 ), 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 : 60-61

Rhinotocinclus halbothi ( Lehmann, Lazzarotto & Reis, 2014) , new combination

( Fig. 33 ; Tab. 6 )

Parotocinclus halbothi Lehmann, Lazzarotto & Reis, 2014:28 (Type-locality: Brazil, Pará, Oriximiná, creek tributary to igarapé do Moura at Platô Monte Branco, rio Trombetas drainage, Amazon basin, 01°35’58.09”S 56°31’21.83”W. Holotype: MCP 48029).

Diagnosis. Rhinotocinclus halbothi is distinguished from all congeners, except R. collinsae and R. hardmanni , by having accessory teeth on both premaxilla and dentary (Fig. 5A; accessory teeth absent, Figs. 5B,C); the odontodes on the ventral surface of first pelvic-fin ray aligned with main ray axis (Fig. 9B; vs. odontodes bent and pointing mesially, Fig. 9A); and lacking a light mark from the snout tip to nostrils (vs. light mark present and Y-, V-shaped or as two separate lines). Rhinotocinclus halbothi 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 a triangular dark spot on the anterior portion of the dorsal-fin membrane (vs. dorsal-fin spot present); and from R. acuen , R. bockmanni , R. chromodontus , R. dani , R. dinizae , R. hera , R. jumaorum , R. pentakelis , R. loxochelis n. sp., and R. marginalis n. sp. by possessing an adipose fin (vs. adipose fin absent). Rhinotocinclus halbothi is distinguished from R. collinsae and R. hardmanni by having 4–7 series of middle abdominal plates (vs. 0–1 series). It is further distinguished from R. collinsae by having the adipose-fin spine coalesced to the dorsum (vs. adipose fin normally developed), and by a shorter pectoral fin (46.3–55.8% vs. 58.2–69.1% HL); and from R. hardmanii by having many and large accessory teeth (vs. few and minute teeth), a normally developed urogenital papilla in males (Fig. 2B; vs. urogenital papilla 3–4 times bigger than normal, Fig. 2C), skin flap on first pelvic-fin ray of males (vs. skin flap absent), and belly fully plated between the lateral abdominal plates (vs. belly naked or almost naked between lateral abdominal plates).

Geographical distribution. Rhinotocinclus halbothi occurs in the rio Trombetas basin, a tributary to the Amazon in the states of Amazonas and Pará, Brazil, and in the upper Marowijne River, in southern Suriname ( Fig. 32 ).

Remarks. Rhinotocinclus halbothi , listed as Parotocinclus halbothi , is currently assessed as Least Concern (LC) in the Brazilian regional assessment by ICMBio (2018).

Material examined. Brazil: MCP 48029 , holotype (measured), MCP 48030 , 6 paratypes (6 measured), MCP 48098 , 1 cs paratype (measured), INPA 39890 , 4 + 1 immature paratypes (4 measured), creek tributary to igarapé do Moura at Platô Monte Branco , rio Trombetas drainage, Oriximiná, Pará, 01°35’58.09”S 56°31’21.83”W. MPEG 17299 , 2 paratypes, igarapé 1500 on track 4, Estação Ecológica Grão-Pará, upper rio Mapuera , rio Trombetas basin, Pará, 01º16’20.8”N 58º41’09.2”W. Suriname: USNM 408454 , 1 paratype, left tributary to upper Paloemeu River , 1 km downstream of basecamp, Marowijne River basin, Sipaliwini, 02º28’38”N 55º38’17”W. USNM 409918 , 2 paratypes, downstream waterfall in right tributary of upper Paloemeu River , Marowijne River basin, Sipaliwini, 02º27’21”N 55º37’35”W.

Figures

FIGURE 32 | Geographical distribution of Rhinotocinclus species of the R. collinsae group in southeastern Guiana Shield. Rhinotocinclus collinsae (yellow dots); R. halbothi (red dots); R. hardmani (blue dots). T = Type-locality

FIGURE 33 | Rhinotocinclus halbothi, holotype, MCP 48029, 19.4 mm SL, female, creek tributary to igarapé do Moura at Platô Monte Branco, rio Trombetas drainage, Oriximiná, Pará, Brazil.