Neoplecostomus watersi, Silva & Reia & Zawadzki & Roxo, 2019

Silva, Gabriel S. C., Reia, Lais, Zawadzki, Cláudio H. & Roxo, Fabio F., 2019, New species of Neoplecostomus (Neoplecostomini: Loricariidae) lacking adipose fin from upper Rio Paraná basin, central Brazil, Zootaxa 4544 (1), pp. 93-102 : 94-99

Neoplecostomus watersi , new species

Figs. 1 , 2 ; Table 1

Holotype. MZUSP 123956 , 69.7 mm SL, male, Goiás state, municipality of Aporé, Córrego da Cachoeira, Rio Correntes drainage, upper Rio Paraná basin, 18°34’50.8” S 52°05’52.8” W, November 2017, B.F. Melo, C. Araya- Jaime, G.S.C. Silva, R. Devidé.

Paratypes. All from Brazil. LBP 25733, 4 (35.9–68.2 mm SL), 1 c&s (53.1 mm SL) collected with holotype. LBP 26440, 4 (47.3–67.5mm SL), Goiás state, municipality of Aporé, Córrego da Cachoeira , Rio Correntes drainage, upper Rio Paraná basin, 18°34’50.8” S 52°05’52.8” W, May 2018, G.S.C. Silva, L. Reia. NUP 20525, 2 (65.9–69.5 mm SL), Goiás state, municipality of Aporé, Córrego da Cachoeira , Rio Correntes drainage, upper Rio Paraná basin, 18°34’50.8” S 52°05’52.8” W, May 2018, G.S.C. Silva, L. Reia .

Diagnosis. Neoplecostomus watersi differs from all congeners by the absence of an adipose fin or azygous plates at the typical adipose-fin location, Figs. 1 , 2 and 3 (vs. presence of a reduced adipose fin or azygous plates in N. botucatu , Fig. 4a,b and N . paranensis, Fig. 4c,d ; and fully-developed adipose fin in all other species). Additionally, the new species differs from N. botucatu and N. paranensis by having a dark caudal fin with a unique v -shaped hyaline vertical area, Figs. 1 and 2 (vs. dark caudal fin with several irregular hyaline vertical bands) and by having lower lip reaching or almost reaching branquial apertures transversal line, Fig. 5 (vs. far from reaching branquial apertures transversal line).

Description. Morphometric and meristic data are summarized in Table 1. Medium-sized loricariid (maximum 69.7 mm of SL). Head wide and depressed. Head and snout rounded in dorsal view. Snout elongated (59.6–66.2% of HL). Dorsal profile of head ascending convexly approximately 45° to parieto-supraoccipital. Eyes relatively small (8.2–11.9% of HL), dorsolaterally positioned, just posterior of midpoint of head. Pronounced ridge from nares to superior margin of orbit. Iris operculum present but poor developed. Presence of inconspicuous odontodes on dorsal and lateral surface of head. Lips well developed, rounded and covered with papillae. Lip margins slightly fringed. Lower lip reaching or almost reaching transverse line of branquial apperture. Two irregular and conspicuous rows of large and transversally flattened papillae, just posterior to dentary teeth; posterior row of papillae distributed along whole dentary ramus. Maxillary barbel short and adnate to lower lip. Teeth long, robust, crown bent inward; crown bicuspid, medial cusp longer than lateral. Dentary rami forming an angle of approximately 125°–130°. Premaxillary teeth 12–15 (mode 14). Dentary teeth 8–10 (mode 8).

Lower surface of head naked. Predorsal region without ridges. In dorsal view, body elongated and compressed on caudal peduncle. Predorsal region without ridges. Greatest body width at cleithral region (25.6–27.4% of SL), progressively narrowing anteriorly towards snout tip and posteriorly towards caudal-fin. Dorsal profile of head and trunk covered by dermal plates, except for naked area around dorsal-fin insertion. In lateral view, body depressed and convex in shape from snout tip to posterior margin of frontal; slight concave from that point to dorsal-fin origin; slightly concave and descending from dorsal-fin origin to first upper procurrent caudal-fin ray, rising posteriorly to insertion of caudal fin. Greatest body depth at unbranched dorsal-fin ray insertion. Ventral portion of body totally covered by plates, except beneath lower lip, around pectoral- and pelvic-fin insertions, and urogenital opening.

In lateral view, ventral profile straight and descending from snout tip to opercular region; slightly convex from opercular region to pectoral-fin origin; convex from that point to pelvic-fin origin; slightly concave from that point to lower procurrent caudal-fin ray origin. Lateral surface of body entirely covered by plates; dorsal series with 25– 27 plates (mode 27). Mid-dorsal plate series truncated, (22–23 plates) not reaching posterior end of caudal peduncle. Lateral plate series with 27–29 plates (mode 28). Lateral line complete. Mid-ventral series of lateral plates developed, reaching middle of caudal peduncle (21–22 plates). Ventral plates series with 23–24 plates (mode 23). body plates covered with minute odontodes.

Dorsal fin ii,7; its origin slightly posterior through pelvic-fin origin. Dorsal-fin unbranched ray slightly convex. Tip of adpressed dorsal-fin rays not surpassing anal-fin origin. Dorsal-fin spinelet small and rounded. Pectoral-fin rays i,6; when adpressed its tip reaching one-third adpressed pelvic-fin unbranched ray. Pelvic-fin rays i,5; its distal margin straight to slightly convex; tip of adpressed pelvic-fin ray reaching anal-fin origin in males, but not in females. Adipose fin absent, not replaced by azygous plates. Anal-fin rays i,5; distal margin slightly convex. Caudal-fin rays i, 7–i,7; emarginate; lower unbranched ray slightly larger than upper unbranched ray. Rays of all fins covered with sharp pointed odontodes. Least body depth at caudal peduncle. Caudal peduncle somewhat rectangular in cross section.

Color in alcohol. Background color of dorsal region of head and trunk dark brown. Four almost inconspicuous dark brown saddles along dorsal portion of body: first at dorsal-fin origin, second at end of dorsal-fin base, third at middle of caudal peduncle, and fourth reaching anteriormost caudal procurrent ray. Mid-lateral dark brown stripe extending from tip of snout to caudal peduncle. Ventral portion of body almost entirely yellowish. Dorsal, pectoral, and pelvic fins with four to five dark stripes. Caudal-fin dark, with one medially vertical v -shaped hyaline area medially ( Fig. 1 ).

Color in life. Similar to the pattern described for specimens in alcohol, but with lighter background ( Fig. 2 ).

Sexual dimorphism. Adult males with papilla covering urogenital opening, long pelvic fin that extends beyond anal-fin origin, and membrane along dorsal portion of unbranched pelvic-fin ray. All these features absent in all analyzed females.

Distribution and habitat. The new species Neoplecostomus watersi is known from Córrego Cachoeira, a

tributary of Rio Corrente in upper Rio Paraná basin, central Brazil ( Fig. 6 and 7 ). The new species was found in clear water, at the bottom of the rivers among and beneath the rocks.

Etymology. The specific name “ watersi ” is in honor to George Roger Waters an English composer, singer and guitar player from the rock ‘n’ roll band Pink Floyd for his talent as musician and social awareness around world, specially his brave concerns to Brazilian economic, social and politic issues.

Figures

FIGURE 1. Neoplecostomus watersi, MZUSP 123956, male, 69.7 mm SL, holotype, from Goiás state, municipality of Aporé, Córrego Cachoeira, upper Rio Paraná basin.

FIGURE 2. Neoplecostomus watersi, MZUSP 123956, 69.7 mm SL, holotype, live specimen, from Córrego Cachoeira, Goiás state, Brazil.

FIGURE 4. Neoplecostomus botucatu (a–b), paratypes, LBP 8065, 75.5–91.4 mm SL; Neoplecostomus paranensis (c–d), LBP 14631, 68.0–76.4 mm SL; right column: spine adpressed and fused to caudal peduncle; left column adipose fin absent with two or three azygous plates in the place of adipose fin.

FIGURE 5. Picture showing the lower lip reaching or almost reaching branquial apertures ansversal line in Neoplecostomus watersi (left image), NUP 20525, 69.5 mm SL, and far from reaching branquial apertures transversal line in N. paranensis (right image), MZUSP 38572, holotype, 71.4 mm SL.

FIGURE 6 Map showing the distribution of Neoplecostomus species. 1) N. watersi, type locality at Córrego Cachoeira, upper Rio Paraná basin, Goiás state, Brazil; 2) N. corumba; 3) N. franciscoensis; 4) N. doceensis; 5) N. espiritosantensis; 6) N. canastra; 7) N. langeanii; 8) N. paranensis; 9) N. paraty; 10) N. bandeirante; 11) N. ribeirensis; 12) N. jaguari; 13) N. botucatu; 14) N. selenae; 15) N. yapo; and 16) N. granosus, N. microps and N. variipictus

FIGURE 7. Habitat of the type locality where Neoplecostomus watersi was collected in the Córrego Cachoeira, 18°34’50.8” S 52°05’52.8” W, Goiás state, Brazil.