Leporinus venerei, Britski & Birindelli, 2008

Britski, Heraldo A. & Birindelli, José L. O., 2008, Description of a new species of the genus Leporinus Spix (Characiformes: Anostomidae) from the rio Araguaia, Brazil, with comments on the taxonomy and distribution of L. parae and L. lacustris, Neotropical Ichthyology 6 (1), pp. 45-45 : 45-

Leporinus venerei , new species

Fig. 1

Holotype: MZUSP 93124 (113.3 mm SL), Mato Grosso, São Felix, Lake in Fazenda Entre-Rios (approx. 11º35’S 50º40’W), 24 Oct 2006; P. C. Venere & C. E. de Melo.

Paratypes: MZUSP 93123 (8, 82.5-105.8 mm SL), collected with holotype . MZUSP 92027 (3, 103.1- 114.3 mm SL), Goias, Aruanã, Fazenda Sobrado, pool at margin of road between Aruanã and Cocalinho (14º45’30"S 50º37’50"W), 25 Jul 2005; C. Chamon, L. Sousa, M. Melo & L. Souza . MZUSP 93125 (3, 92.2-106.4 mm SL), Mato Grosso, Araguaiana, Córrego and Cacimbas (borrow pits) at Fazenda do Italiano (approx. 15º43’S 51º51’W), 06 Jul 1995; P. C. Venere & C. E. Melo . MZUSP 93122 (6, 98.1-135.5 mm SL), Mato Grosso, Araguaiana, Ribeirão Dois de Agosto, tributary of rio Pindaíba , rio das Mortes drainage (approx. 15º15’S 51º45’W), 30 Jun 1992; P. C. Venere & C. E. Melo .

Diagnosis. Leporinus venerei is distinguished from its congeners by having 4 teeth on the premaxilla and 3 teeth on the dentary yielding the dental formula 4/3 (vs. 3/3, 3/4 or 4/ 4 in all other species of Leporinus ). Leporinus venerei is also diagnosed by the following combination of non-unique characteristics: presence of 36-37 pored scales in the lateral line, 4 scales in transversal series from origin of dorsal fin to lateral line and 4.5 to 5 scales from lateral line to base of pelvic fin; 16 series of scales around caudal peduncle; three round dark blotches on lateral line, the first at vertical through dorsal fin, the second at vertical through adipose-fin origin and the third at base of caudal peduncle (the latter two blotches, particularly the last one, usually small or inconspicuous).

Comparisons. Leporinus parae Eigenmann, 1907 , and L. lacustris Campos, 1945 , are most similar in overall appearance (body shape and coloration) to L. venerei , but both species have dental formula 4/4 (vs. 4/ 3 in L. venerei ). In addition L. parae has 38 to 41 and L. lacustris 33 to 35 lateralline scales (vs. 36-37 in L. venerei ) and L. parae has 5 scales in transverse series from lateral line to dorsal-fin origin (vs. 4 in L. venerei ).

Description. See Table 1 for morphometric data of 21 examined specimens and Fig. 1 for lateral view of holotype. Small sized species for genus Leporinus , largest examined specimen 135.5 mm SL. Body rather elevated and compressed. Dorsal profile straight from anterodorsal portion of snout to posterior tip of supraoccipital; straight or very slightly convex from that point to dorsal-fin origin; straight along dorsalfin base; slightly convex or straight from dorsal-fin base to adipose fin and slightly concave from adipose fin to caudalfin origin. Ventral profile slightly convex from tip of lower jaw to pelvic-fin insertion, (convexity less pronounced below branchial region in some specimens); straight from pelvic-fin base to anal-fin origin; straight at anal-fin base and concave from anal fin to caudal fin. Greatest body depth at origin of dorsal fin. Head somewhat compressed; mouth terminal, anterior opening of mouth positioned at horizontal bisecting eye.

Premaxillary with four teeth diminishing in size laterally from the symphyseal tooth. Dentary with three teeth also decreasing in size laterally. Teeth on both jaws of stair-step type.

Dorsal-fin rays ii+11* or iii+11; dorsal-fin origin slightly in front of vertical through pelvic-fin origin; dorsal-fin base extending through seven or eight scales. Pectoral-fin rays i+13, 14* or 15; pectoral fin extending to third or fourth scale anterior to pelvic-fin base. Pelvic-fin rays i+8; pelvic fin extending to four or five scale posterior to fin base. Anal-fin rays ii-9 or iii+9*; anal fin clearly surpassing base of lower caudal-fin rays; distal margin of anal fin straight or slightly convex. Length of last anal fin ray 26 to 47% (mean 36%) length of first branched anal-fin ray. Caudal-fin rays i+17+i; caudal fin forked, upper lobe slightly more developed than lower lobe. Vertebrae 34 (n=4) to 35 (3).

Scales with few radii (5-7). Lateral line complete with 36 (5) to 37* (13) perforated scales; transversal series with 4 (21)

H. A. Britski & J. L. O. Birindelli 47

scales from dorsal-fin origin to lateral line and 4.5 (6) to 5* (15) scales from lateral line to pelvic-fin base; 9, 10* or 11 predorsal scales; 10 to 12* scales in median dorsal row between dorsal fin and adipose fin; 7* or 8 scales in median dorsal row between adipose fin and caudal fin; 14 to 18* prepelvic scales; 9, 10* or 11 scales in median ventral row

48 Description of a new species of the genus Leporinus between pelvic fin and anus; 1, 2* or 3 scales in median ventral row between anus and anal fin; 6 to 7* scales in median ventral row between anal fin and caudal fin; 16 horizontal scale rows around caudal peduncle.

Coloration in alcohol. Overall ground color tan. Dorsal surface of head with small, dark-brown chromatophores uniformly scattered or concentrated in some areas, forming faint transverse bars: one at level of nares, another at level of interorbital space and sometimes a, barely visible pair of bars, each one starting on the lateral portion of posterior bar and extending anteriorly into interorbital area. Lateral and ventral surfaces of head pale, without chromatophores, except the bright silver opercular series; sometimes with a black blotch on its ventral portion. Body gradually darker from lateral line dorsally. Three dark blotches on lateral line: first blotch at vertical through posterior half of dorsal-fin base; second at level of the fifth or sixth scale anterior to adipose fin base and third at base of caudal peduncle; only first blotch usually conspicuous; second and third blotches generally reduced in size, faded or, occasionally, completely absent. Brown chromatophores bordering posterior edge of each scale giving a relatively gray reticulated aspect to body ground coloration. Some individuals with faint transverse bars on dorsum occasionally extended onto ventral portion of body. With exception of anal and adipose, remaining fins nearly hyaline with few chromatophores along margins of rays; anal fin dark brown, sometimes with whitish areas along its posterior margin; adipose fin usually whitish near base and dark brown distally.

Distribution. The new species is only known from the rio Araguaia basin in Mato Grosso and Goiás states in central Brazil (see Fig. 2 ).

Ecological note. Leporinus venerei is found in lentic environments such as lagoons or borrow pits.

Etymology. The name venerei is given in honor to Paulo Cesar Venere who collected the first known specimens of this new species.

Figures

Fig. 1. Photograph in lateral view of (a) Leporinus venerei (holotype, MZUSP 93124, 113.3 mm SL), (b) Leporinus parae (MZUSP 48445, 111.9 mm SL), and (c) Leporinus lacustris (MZUSP 48414, 95.0 mm SL).

Fig. 2. Map of South America, showing the distribution of Leporinus venerei (dots), Leporinus parae (triangles) and Leporinus lacustris (squares); open symbols indicates typelocalities.