Bryconamericus patriciae, Silva, 2004

Silva, José Francisco Pezzi da, 2004, Two new species of Bryconamericus Eigenmann (Characiformes: Characidae) from southern Brazil, Neotropical Ichthyology 2 (2), pp. 55-60 : 56-58

Bryconamericus patriciae , new species Fig. 1

Holotype: MCP 19615 (47.6 mm SL, male) creek tributary of rio Pelotas, on road from Silveira to Rondinha (rio Uruguay drainage), Bom Jesus , Rio Grande do Sul, Brazil, 14 January 1989, C. A. S. Lucena, E. H. L. Pereira & P. V. Azevedo.

Paratypes: Brazil: Rio Grande do Sul: Vacaria : MCP 14376, (936, 7c&s, 15.1-61.5 mm SL) , MZUSP 84302 (20, 38.5-53.5 mm SL) , MNRJ 26438 (20, 37.4-56.1 mm SL) collected with the holotype ; MCP 11632 (19), arroio São Paulino, on road from Vacaria to Bom Jesus (tributary of rio Quebra-Dentes , laguna dos Patos drainage) (approx. 28 o 33’S 50 o 48’W), 2 May 1985, C. A. S. de Lucena, L . R. Malabarba & R. E. Reis. Bom Jesus : MCP 11637 (3), rio Manoel Leão near São José dos Ausentes (tributary of rio Pelotas , rio Uruguay drainage) (approx. 28 o 48’S 50 o 03’W) , 2 May 1985, C. A. S. Lucena, L. R. Malabarba , & R. E. Reis .

Diagnosis. Bryconamericus patriciae differs from other Bryconamericus species, from southern South America, by the combination of body depth (25.5-30.3% of SL, mean 28.0 versus 31.2-39.3%, mean 34.6 in B. iheringii ; 33.7-36.4% of SL, mean 34.8 in B. ikaa ; and 30.5-36.9%, mean 34.4 in B. ecai ); head length (25.2-27.6% of SL, mean 26.3 versus 22.5- 25.3%, mean 23.6 in B. lambari ); pelvic fin length (11.0-14.4% of SL, mean 12.5 versus 14.2-18.0%, mean 15.5 (female), 16.3- 21.3%, mean 18.3 (male) in B. rubropictus ); branched anal-fin rays (14-18 versus 19-22 in B. agna ; and 22-25 in B. sylvicola ); teeth of outer row of premaxilla regularly implanted (versus irregularly implanted in B. stramineus and B. exodon ); teeth of inner row of premaxilla pentacuspid (versus heptacuspid in B. uporas ); teeth compressed distally (versus teeth massive in B. microcephalus , B. ornaticeps , and B. tenuis ); males with bony hooks on pelvic and anal fins (males without bony hooks on pelvic and anal fins in B. menni and B. pyahu ).

Description. Morphometric data summarized in Table 1 . Body laterally compressed. Greatest body depth at origin of dorsal fin. Dorsal profile of body slightly convex from tip of supraoccipital to dorsal fin origin, nearly straight from posterior dorsal-fin base to adipose fin, and gently concave from adipose-fin base to caudal-fin origin. Ventral body profile slightly convex from isthmus to anal-fin origin, straight along anal-fin base, and gently concave from posterior of anal-fin base to caudal-fin origin.

Mouth sub-terminal, lower jaw shorter than upper jaw. Snout profile rounded from margin of upper lip to vertical through anterior nostrils, slightly convex from that point to supraoccipital. Ventral profile of head gently convex. Premaxilla with two series of teeth. Four teeth in inner row with three to five cusps, central cusp greater than others; 3 or 4 tricuspid teeth in outer row; teeth of inner row distinctly larger than teeth of outer row. Dentary with 9 to 12 teeth. Anterior six dentary teeth largest, with 3 to 5 cusps; posterior 3 to 6 teeth progressively smaller, tricuspid or conical. Maxilla with 4 to 6, usually tricuspid teeth.

Dorsal-fin rays ii,8. First unbranched dorsal-fin ray about half length of second ray. Posterior border of dorsal fin straight; tip not reaching adipose fin when fin depressed. Dorsal-fin origin situated slightly posterior to middle of body. Adiposefin origin located at vertical through insertion of last anal-fin ray. Anal-fin rays iii-iv,14-18 (iii,17). Anal fin origin at vertical through insertion of last dorsal-fin ray. Distal border of anal fin straight or slightly concave. Anal-fin rays in males with few and tiny bony hooks, from last unbranched ray to 8th branched ray, one pair of hooks per segment and up to 10 pairs per ray, present in posterolateral surface of ray. Female without hooks on anal fin. Pectoral-fin rays i, 10-12 (i,10), distal margin slightly rounded, not reaching pelvic-fin origin. Pelvic-fin rays i,6-7 (i,6), distal margin rounded, not reaching anal-fin origin. Pelvicfin origin slightly anterior to vertical through dorsal-fin origin. Pelvic fin with few and tiny bony hooks in males, more elongate that anal bony hooks, in ventromedial surface of each ray, one hook per segment, absent on unbranched ray. Females without hooks on pelvic fin. Caudal fin forked, margin of lobes rounded, equal in size. Principal caudal-fin rays 19; 13-16 procurrent rays dorsally and 10-14 ventrally.

58 Two new species of Bryconamericus Eigenmann from southern Brazil

Scales cycloid. Caudal fin not scaled. Single row of 4-9 (6) scales covering base of anteriormost anal-fin rays. Lateral line complete, 37-40 (38) perforated scales; 5-6 (5) scales in transverse series from dorsal-fin origin to lateral line; 4-5 (5) scales between lateral line and anal-fin origin. Predorsal scales 13-15 (15), sometimes in irregular series. Scales around caudal peduncle 14. Vertebrae: precaudal 16-17, caudal 20- 21. Supraneurals 5-6 (in seven c&s specimens).

Color in alcohol. Ground color tan. Dorsal portions of head and body region above midlateral stripe more pigmented. Dark midlateral stripe present, more conspicuous posterior to vertical through dorsal-fin origin, not reaching upper and lower borders of caudal peduncle and not extending on base of caudal fin rays. Humeral spot faint, vertically elongate, centered on third or fourth scales of pored lateral line, and extended two series above and one below it. Pectoral, ventral, and caudal fins hyaline. Dorsal and anal fins slightly covered by dark chromatophores.

Distribution. Bryconamericus patriciae is know from the headwaters of rio Pelotas (rio Uruguay drainage) and rio das Antas (laguna dos Patos drainage) ( Fig. 2 ).

Etymology. The specific name patriciae is given in honor to my wife Patrícia L. Gonçalves.

Habitat. Bryconamericus patriciae has been collected in rivers and creeks with clear water and light to strong water current. The bottom was formed by rocks, stones, and in some points gravel and sand. The fishes are usually found in pools below the rapids. The water temperature can drop to 7 oC during the winter.

Figures

Fig. 1. Bryconamericus patriciae, holotype, MCP 19615 (47.6

Fig. 2. Distribution of the new species of Bryconamericus - B. patriciae (squares, open square is type-locality) and B. ecai (circle).