Rhinotocinclus pentakelis ( Roxo, Messias & Silva, 2019 ), 2022

Rhinotocinclus pentakelis ( Roxo, Messias & Silva, 2019) , new combination

( Fig. 39 View FIGURE 39 ; Tab. 8 View TABLE 8 )

Parotocinclus pentakelis Roxo, Messias & Silva, 2019:347 (Type-locality: Brazil, Tocantins State, municipality Lavandeira, Rio Palmas, Rio Tocantins basin; 12°48’05”S 46°28’38”W. Holotype: MZUSP 124900).

Diagnosis. 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 color pattern formed by dark bars on body well separated and distinct (Fig. 7D; vs. dominant color 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 (Figs. 6E,F; vs. light lines on snout absent, Y- or V-shaped); and by having teeth with yellow cusps (Fig. 5C; vs. 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).

Geographical distribution. Rhinotocinclus pentakelis is only known from two localities in tributaries to the rio Tocantins in the state of Tocantins, Brazil ( Fig. 36 View FIGURE 36 ).

Remarks. In the original description, Parotocinclus pentakelis was named and diagnosed from remaining Parotocinclus species, except P. dani , by possessing five conspicuous dark bars on body, compared to three or four dark bars of other Parotocinclus species. In fact, however, remaining Amazon basin Parotocinclus , now all transferred to Rhinotocinclus , possess five dark bars (Fig. 7). Extintion risk of Rhinotocinclus pentakelis is currently not assessed.

Material examined. MCP 54394, 36 (16 measured) + 2 cs, rio Palma at Lavandeira, rio Tocantins basin, Tocantins, Brazil, 12°47’41.03”S 46°30’46.20”W. GoogleMaps