Two new species of Bryconamericus Eigenmann ( Characiformes : Characidae ) from southern Brazil

Two new species of Bryconamericus are described from southern Brazil: B. patriciae, from the headwaters of rio Pelotas (rio Uruguay drainage) and rio das Antas (laguna dos Patos drainage) and B. ecai from lower rio Taquari drainage. Bryconamericus patriciae differs from other Bryconamericus species from southern South America, by the following combination of characters: body depth (25.5-30.3% SL); head length (25.2-27.6% SL); pelvic-fin length (11.0-14.4% SL); branched anal-fin rays 14-18; teeth of outer row of premaxilla regularly implanted; teeth of inner row of premaxilla pentacuspid; teeth compressed distally; and males with bony hooks on pelvic and anal fins. Bryconamericus ecai differs from other Bryconamericus species from southern South America by the following combination of characters: body depth (33.1-36.9% SL); eye diameter (31.1-33.9% HL); snout length (26.8-32.4% HL); branched anal-fin rays 15-18; teeth of outer row of premaxilla regularly implanted; teeth of inner row of premaxilla tricuspid or pentacuspid; teeth compressed distally; and males with bony hooks on pelvic and anal fins.


Introduction
Bryconamericus Eigenmann (in Eigenmann, McAtee & Ward, 1907) is a speciose characid genus, with 51 species currently considered valid (Lima et al., 2003) inhabiting a variety of freshwater ecosystems at lower altitudes across a broad extension of South and Central America in both sides of the Andean cordilleras (Vari & Siebert, 1990).In southern South America there are sixteen valid species for the genus: The systematics of Bryconamericus is still unresolved and the genus lacks a phylogenetic diagnosis.The present definition was proposed by Eigenmann (1927), who included in Bryconamericus characid species that posses the following combination of characters: two rows of teeth on the premaxilla with four teeth in the inner series, a low number of teeth along
the anterior margin of the maxilla, lack of scales on the caudal fin, a large third infraorbital contacting the preopercle along its posterior and ventral margins, setiform gillrakers, a complete laterosensory canal system on the body, and the absence of a glandular pouch on the caudal fin in males.None of the listed characters is unique to the genus and most of them are actually plesiomorphic within Characidae.This paper aims to describe two new species of Bryconamericus from southern Brazil.

Material and Methods
Counts and measurements were taken following Fink & Weitzman (1974), except in the anal-fin base length, taken from the base of the first ray to base of the last ray of the anal fin.Counts of vertebrae including the four vertebrae of the Weberian apparatus, supraneurals, and procurrent caudal fin rays were taken from cleared and stained specimens.In the description, number enclosed by brackets after the counts are data of holotype.Data on counts and measurements for Bryconamericus agna, B. eigenmanni, B. exodon, B. ikaa, B. menni, B. pyahu, B. rubropictus, B. sylvicola, and B. thomasi were taken in the literature, while data of other species cited here were taken by the author (see comparative material).The following abbreviations are used: MACN, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Argentina; MCP, Museu de Ciências e Tecnologia, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre; MLP, Museo de La Plata, Argentina; MNRJ, Museu Nacional, Rio de Janeiro and MZUSP, Museu de Zoologia da Universidade de São Paulo, São Paulo.Other abbreviations are: SL, standard length; HL, head length; and c&s, cleared and stained for cartilage and bone according to the procedure described by Taylor & Van Dyke (1985).

Bryconamericus patriciae, new species
Fig 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  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.
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 o C during the winter.Paratypes: MCP 17494, (75, 7 c&s, 13.6-75.1 mm SL), collected with the holotype.

P R O O F S
anal-fin origin, straight along anal-fin base, and gently concave from posterior anal-fin base to caudal fin.Mouth sub-terminal, lower jaw shorter than upper jaw.Snout profile rounded from margin of upper lip to vertical through anterior nostrils, nearly straight from that point to supraoccipital.Ventral profile of head gently convex.Premaxilla with two series of teeth with three to five cusps, central cusp largest, teeth with same size in both series.Inner row with four teeth, 3 to 5 in outer row.Dentary with 8 to 10 teeth.Anterior 4 to 5 dentary teeth largest, with 3 to 5 cusps, with 3 to 5 posterior teeth becoming progressively smaller, tricuspid or conical.Maxilla with 3 to 4 teeth, with 3 to 5 cusps, approximately equal in size.
Dorsal-fin rays ii,8.First unbranched dorsal-fin ray about half length of second unbranched ray.Dorsal fin posterior border straight; it tip not reaching adipose fin when depressed.Dorsal-fin origin approximately at mid-length of body.Adipose-fin origin located slightly anterior to vertical through insertion of last anal-fin ray.Anal-fin rays iii-iv, 15-18 (iii,18).Anal fin origin slightly anterior to vertical through insertion of last dorsal-fin ray.Distal border of anal fin slightly concave.Last unbranched to 7th branched anal-fin rays with few, tiny bony hooks, one pair per segment.Up to 16 hook pairs per ray, usually 10-13.Hooks present in posterolateral surface of ray.Females without hooks on anal fin.Pectoral-fin rays i, 10-12 (i, 11), distal margin slightly rounded, not reaching pelvicfin origin.Pelvic-fin rays i, 6-7 (i, 7), distal margin straight, not reaching anal fin origin.Pelvic-fin origin slightly anterior of vertical through dorsal-fin origin.Male pelvic fin with thin bony hooks, more elongate than anal bony hooks, present in ventromedial surface of each ray, with one hook per segment, absent on unbranched ray.Females without hooks on pelvic fin.Caudal fin forked, lobes rounded, equal in size, not scaled.Principal caudal-fin rays 19; 11-12 procurrent rays dorsally and 10-12 ventrally.
Color in alcohol.Ground color tan.Dorsal portions of head and body region above midlateral stripe more pigmented.Dark midlateral stripe, more conspicuous posterior to vertical through distal border of pectoral fin, expanded into faint, small horizontally elongate spot on caudal peduncle, not reaching upper and lower margins of caudal peduncle and extending on base of caudal fin rays.Two humeral spots, first, vertically elongate, centered on third or fourth scales of pored lateral line and extended two series above; second spot more diffuse, without clearly marked limits.Pectoral and pelvic fins hyaline.Dorsal, anal, and caudal fin with scattered dark chromatophores Etymology.From the Tupi-Guarani eçai, meaning small eye, in allusion to the smaller eye diameter in comparison to other Bryconamericus species.
Distribution.So far known from the type-locality a creek tributary of the lower portion of rio Taquari (laguna dos Patos drainage), Rio Grande do Sul, Brazil.
Habitat.Bryconamericus ecai was found in a creek with clear to turbid water, light to moderate water current and bottom with stones and sand.

Table 1 .
Morphometric data for Bryconamericus patriciae and B. ecai (n= number of specimens measured).