Leporinus britskii, Feitosa, Francimário Da S., Dos, Geraldo M. & Birindelli, José L. O., 2011

Feitosa, Francimário Da S., Dos, Geraldo M. & Birindelli, José L. O., 2011, Leporinus britskii: a new anostomid species from the Tapajós and Jari drainages, Brazil (Characiformes: Anostomidae), Zootaxa 3120, pp. 55-62 : 56-61

Leporinus britskii , new species

Figures 1 and 2

Holotype. MZUSP 109771 (88.86 mm SL), rio Jamanxim, near Vila Mil, 7°43’51’’S 55°16’36’’W, Novo Progresso, Pará, 23 Oct 2007, J. L. O. Birindelli, L. M. Sousa, A. Netto Ferreira, M. H. Sabaj Pérez, N. K. Lujan.

Paratypes. All from Brazil. ANSP 192112 (5, 81.6-108.8 mm SL), INPA 33711 (5, 76.7-102.2 mm SL), MZUSP 97374 (19, 54.6-123.5 mm SL); collected with holotype. INPA 6648 (2, 78.8-99.8 mm SL), rio Jamanxim, at Ilha Terra Preta, 4°58’6”S 56°29’12”W, Pará, 19-20 Dec 1991, L. Py-Daniel & J. Zuanon. INPA 6702 (5, 79.3- 89.3 mm SL), rio Jamanxim, at Ilha Terra Preta, 4°58’6”S 56°29’12”W, Pará, 19 Out 1991, L. Py-Daniel & J. Zuanon. INPA 6809 (4, 58.6-89.1 mm SL), rio Jamanxim, at Ilha Terra Preta, 4°58’6”S 56°29’12”W, Pará, 20 Out 1991, L. Py-Daniel. MZUSP 97279 (13, 42.7-100.4 mm SL), rio Jamanxim, near Castelo dos Sonhos, 8°11’4’’S 55°21’28’’W, Novo Progresso, Pará, 23 Oct 2007, J. L. O. Birindelli et al.

Non-type specimens. INPA 36466 (3, 89.7-93.1 mm SL), MZUSP 103484 (11, 95.4-105.6 mm SL); rio Iratapuru, tributary of rio Jari, at Cachoeira São Raimundo, 0°33’59’’S 52°34’40’’W, Laranjal do Jari, Amapá, 20 Feb 2009, J. L. O. Birindelli, L. M. Sousa, M. Soares. INPA 35239 (2, 70.9-90.3 mm SL), rio Teles Pires, at Cachoeira de Sete Quedas, 9°30’44’’S 56°49’42’’W, Mato Grosso, 1 Fev 2009, E. Ferreira et al. INPA 35243 (4, 41.6-71.7 mm SL), rio Paranaíta, tributary of rio Teles Pires, 9°30’44’’S 56°49’42’’W, Mato Grosso, 1 Fev 2009, E. Ferreira et al. MZUSP 101752 (1, 96.7 mm SL), rio Iratapuru, tributary of rio Jari, at Cachoeira São Raimundo, 0°33’59’’S 52°34’40’’W, Laranjal do Jari, Amapá, 13 Sep 2008, J. L. O. Birindelli & P. Hollanda-Carvalho.

Diagnosis. Leporinus britskii is distinguished from congeners, except L. amblyrhynchus , L. geminis , L. taeniatus , L. taeniofasciatus , L. unitaeniatus , L. vanzoi , by having a dark longitudinal midlateral stripe and dark transversal bars on dorsum. Leporinus britskii is distinguished from L. amblyrhynchus by having four teeth on dentary (vs. three); from L. taeniatus by having 12 circumpeduncular scale series (vs. 16) and 37 to 39 scales on lateral line (vs. 36 to 37); from L. taeniofasciatus by having 12 circumpeduncular scale series (vs. 16); from L. geminis , L. unitaeniatus and L. vanzoi by having three teeth on premaxilla (vs. four), 37 to 39 scales on lateral line (vs. 40 to 43), four or five scale series above lateral line (vs. six), and 12 circumpeduncular scale series (vs. 16).

Description. Morphometric data of holotype and examined specimens presented in Table 1. Relatively small sized when compared to congeners; largest examined specimen 123.5 mm SL. Body elongate, moderately compressed. Dorsal profile distinctly convex from upper lip to vertical through anterior nostril, then gently convex to dorsal-fin origin, straight from dorsal-fin base terminus to adipose-fin origin, and distinctly concave from adiposefin origin to anteriormost dorsal caudal-fin procurrent rays. Ventral profile distinctly convex from lower jaw to posterior insertion of anal-fin rays, and gently concave from this point to origin of lower lobe of caudal-fin. Greatest body depth at dorsal-fin origin. Head somewhat compressed.

Mouth subterminal, gap reaching slightly ventrally to longitudinal through lower margin of orbit, in specimens around 50 mm SL, and to longitudinal through lower margin of infraorbitals, in specimens of 80 mm SL or more. Snout distinctly rounded. Premaxilla with three incisiform teeth gently diminishing in size from symphyseal tooth. Dentary with four incisiform teeth also gradually decreasing in size laterally.

rio Tapajós basin rio Jari basin

Holotype n Mean Range SD n Mean Range SD

Standard length (mm) 88.86 27 91.94 43.4 - 123.46 13 92.52 28.16 - 105.63

Percentages in standard length

Body depth 22.43 25 21.89 19.22 - 24.32 1.06 12 22.98 21.65 - 24.37 0.92 Body width 12.85 25 13.00 10.46 - 15.18 1.02 12 14.22 13.01 - 15.41 0.70 Head length 24.47 25 24.45 23.34 - 25.67 0.64 12 24.04 22.54 - 24.81 0.66 Head width 13.18 25 13.10 11.47 - 16.61 0.98 12 12.94 12.53 - 14.06 0.45 Predorsal distance 48.99 25 47.60 46.23 - 49.94 0.94 12 47.38 45.34 - 49.44 1.00 Prepelvic distance 51.05 25 50.05 48.53 - 52.74 0.91 12 48.94 47.55 - 50.30 0.76 Preanal distance 79.32 25 78.43 77.12 - 80.05 0.82 12 79.51 78.19 - 80.31 0.73 Caudal peduncle length 11.31 25 12.51 11.03 - 14.05 0.84 12 11.80 10.74 - 13.34 0.90 Caudal peduncle depth 9.22 25 8.94 7.76 - 9.83 0.39 12 9.13 8.75 - 9.64 0.29

Percentages in head length

Snout length 44.42 25 44.42 41.12 - 47.59 1.76 12 44.90 41.75 - 47.28 1.76 Eye diameter 23.34 25 23.34 20.38 - 27.16 1.60 12 23.63 21.62 - 25.60 1.07 Bony interorbital 31.14 25 31.14 28.23 - 32.72 1.14 12 33.12 30.21 - 35.87 1.55 Dorsal fin ii, 10* (n=36) or 11 (n=1), origin slightly in front of vertical through pelvic-fin origin; fin-base six scales in length, distal margin concave dorsally and convex ventrally. Pectoral fin i,14 (n=6), 15 (n=9), or 16* (n=22), extending through about seven scales from fin base, distal margin convex. Pelvic fin i,8 (n=37), extending through six or seven scales, distal margin convex. Anal fin ii,8 (n=37), anal-fin origin at vertical through third or fourth scale anterior to adipose-fin origin; adpressed fin usually reaching base of lower caudal-fin rays, distal margin straight or slightly convex. Caudal-fin rays i,8,9,i* (n=36), or i,8,8,i (n=1) forked, lobes rounded, upper lobe usually slightly more elongate than lower lobe.

Scale immediately dorsal to lateral line and at vertical through dorsal-fin origin with seven to ten posteriorly directed radii (n=3). Lateral line complete with 37 (n=12), 38 (n=20) or 39* (n=5) perforated scales. Four (n=9) or 5* (n=28) longitudinal scales series from dorsal-fin origin to lateral line; 4 (n=37) longitudinal series of scales from lateral line to pelvic-fin base; and 4 (n=37) longitudinal scales series from lateral line to anal-fin base. Predorsal scales 10 (n=7), 11 (n=26) or 12* (n=4). Twelve (n=36) horizontal scale rows around caudal peduncle (exceptionally 14 in a single specimen).

Coloration. Overall ground color tan. Head and body slightly countershaded, gradually darker above midlateral line from mouth to caudal fin. Body with a dark midlateral stripe formed by the fusion of eight to ten dark blotches, with stripe conspicuously formed in most specimens, whereas dark blotches somewhat visible as separate blotches in others. Body with a row of dark blotches or spots below the midlateral stripes in most specimens (dark blotches or spots faded in some specimens larger than 90 mm SL). Body also with 10 to 12 dark transversal bars on dorsum, ventrally extended on two or three scale series, four or five bars between opercle and dorsal-fin origin, two on dorsal-fin base, three or four between dorsal-fin terminus and adipose-fin origin, one between adipose-fin terminus and caudal fin. Midlateral dark stripe extended anteriorly throughout head and snout. Upper lip darkened. Small specimens (up to 40 mm SL) with a distinct dark spot on median portion of caudal-fin base, which fades and disappears in larger specimens.

Live coloration ( Fig. 2 ) as described above, except for whitish ventral portion of head and body, and gold reflexes on lateral portion of head and anterior body. Scales on dorsal portion of body distinctly dark on anterior half and silver of posterior half. Pelvic and anteriormost anal-fin rays whitish, adipose fin with a pale red blotch on its center, remaining fins tan.

Geographic distribution. Leporinus britskii is known from the rio Teles Pires, which forms the rio Tapajós after its confluence with rio Juruena, and rio Jamanxim, a tributary of the right margin of the lower rio Tapajós, itself a tributary of the right margin of the rio Amazonas, and from the rio Jari, a tributary of the left margin of the rio Amazonas, in Pará, Brazil ( Fig. 3 ).

Etymology. In honor of Heraldo Antonio Britski, of the Museu de Zoologia of the Universidade de São Paulo, for his valuable contribution to our knowledge of Neotropical fishes, and especially for his important role in our understanding of Leporinus taxonomy (e.g., Britski, 1976; Britski & Garavello, 1978; Britski & Birindelli, 2008).

Remarks. Leporinus britskii is known from two independent drainages: Tapajós and Jari. The meristic and morphometric data of the specimens from both basins are completely overlapping. Although the coloration of the specimens from both drainages is very similar, specimens from the Tapajós seem to have the dark midlateral stripe more conspicuously formed, with straight upper and lower margins, and relatively small dark spots below the midlateral stripe, spots approximately as large as a scale ( Figs. 1 a-c, 2a); whereas specimens from the Jari have the midlateral stripe usually not completely formed, with irregular margins, and relatively large dark blotches below the midlateral stripe, blotches slightly larger than a scale ( Figs. 2 d-f, 3b). In addition, some specimens from the Tapajós have more lateral line scales (39), although the mode of lateral-line scales for specimens from both basins is 38. Since the only differences between specimens from the Tapajós and Jari are small variations in coloration, we prefer to include all specimens herein examined in the same species, restricting the type series to the specimens from the rio Jamanxim. More data, especially those from molecular-based studies, are necessary to investigate if the specimens from the Tapajós and Jari are in fact conspecific.

Leporinus britskii shares with L. amae , L. bistriatus , L. garmani , L. guttatus , L. marcgravii , L. microphthalmus , L. octomaculatus , and L. sexstriatus the combination of dental formula 3/4 and 12 circumpeduncular scale series. Leporinus britskii is distinguished from the aforementioned species in having a dark midlateral stripe and dark transversal bars on dorsum. Nevertheless, some specimens of Leporinus britskii from the rio Jari have dark blotches on the side of the body not completely united into a midlateral stripe ( Figs. 1 f; 2b), resembling specimens of Leporinus octomaculatus . The latter is diagnosed by having eight large dark blotches on the side of the body, which are never united into a midlateral stripe. In addition, Leporinus britskii is also distinguished from L. octomaculatus by having slightly more lateral-line scales (37 to 39, mode 38, vs. 36 to 38, mode 37), and more scales series along transversal line (four or five above and four below lateral line, vs. four above and three or four below).

Comparative material examined. Leporinus amblyrhynchus : MZUSP 14411 (holotype, 131.8 mm SL), rio Tietê, at Fazenda Pau d’Alho, Itu, São Paulo, Dec 1972, U.R.M. de Souza. MZUSP 14412 (8, paratypes, 69.3– 118.1 mm SL), rio Paraná (cofferdam), Ilha Solteira, São Paulo, Sep 1985, Expedição do Departamento de Zoologia [=H.A. Britski et al.]. MZUSP 37403 (14, paratypes, 130.6–164.8 mm SL), rio Paranapanema, São Paulo, 2 Apr 1971, Equipe CESP Promissão. MZUSP 7, 102.4– 116.6 mm SL), rio Barra Grande, near its mouth on rio Tibagi, Telêmaco Borba, Paraná, 14 Nov 2004, A. Akama. MZUSP 88636 (6, 98.6–154.9 mm SL), rio Pardo, 21°34’26’’S 46°42’24’’W, Caconde, São Paulo, 23 Sep 2005, I. Fichberg. Leporinus geminis : MZUSP 14422 (holotype, 140 mm SL), rio Tocantins, Marabá, Pará, 18 Oct to 11 Nov 1974, R.S. Rosa. MZUSP 54550 (1, 108.8 mm SL), rio Araguaia, São Francisco do Araguaia, Mato Grosso, Fev 1998, Coleção Rio Araguaia. MZUSP 60407 (1, 128.6 mm SL), rio Araguaia, 15°52’3’’S 51°58’17’’W, Barra do Garças, Mato Grosso, 6-7 Oct 1997, W. Barrela et al. MZUSP 83806 (1, 116.5 mm SL), rio Palmeiras, 12°15’43’’S 46°53’36’’W, Ponte Alta do Bom Jesus, Tocantins, 17 Nov 2002, C.R. Moreira & J.C. Nolasco. MZUSP 84121 (2, 111.5– 152.1 mm SL), rio Palmeiras, 11°37’’51’’S 46°25’58’’W, Dianópolis, Tocantins, 4 Aug 2002, C.R. Moreira & J.C. Nolasco. Leporinus taeniatus : MZUSP 47459 (3, 65.3–96.0 mm SL), rio Verde, Montes Claros, Minas Gerais, 23 Jul 1994, Expedição MZUSP / UFSCar/ USNM. MZUSP 54663 (12, 60.3–109.3 mm SL), rio Verde Grande, 16°39’1’’S 43°42’49’’W, Montes Claros, Minas Gerais, 20 Jul 1993, R.E. Reis et al. MZUSP 73691 (1, 131.1 mm SL), rio Curimataí, at Fazenda Vitória, 18°5’43’’S 44°16’15’’W, Augusto de Lima, Minas Gerais, 16 Aug 2001, C.B.M. Alves & P.S. Pompeu.

MZUSP 73784 (1, 76.8 mm SL), rio Curimataí, at Fazenda Vitória, 18°5’43’’S 44°16’15’’W, Augusto de Lima, Minas Gerais, 16 Aug 2001, C.B.M. Alves & P.S. Pompeu. Leporinus taeniofasciatus : MZUSP 51073 (holotype, 98.0 mm SL), rio Maranhão, at Cachoeira do Machadinho, Niquelândia, Goiás, 9 Oct 1995, E.P. Caramaschi et al. MZUSP 51214 (3, paratypes, 100.0– 111.4 mm SL), rio Maranhão, at Porto Alfredinho, Niquelândia, Goiás, 5 Feb 1996, E.P. Caramaschi et al. MZUSP 51216 (2, paratypes, 126.0– 129.7 mm SL), rio Maranhão, near mouth of rio do Peixe, Niquelândia, Goiás, 8 Fev 1996, E.P. Caramaschi et al. Leporinus unitaeniatus : MZUSP 14427 (holotype, 105.5 mm SL), rio Araguaia, 10°35’S 50°34’W, Santa Terezinha, Mato Grosso, Oct 1964, H.A. Britski. MZUSP 14429 (5, paratypes, 70.0–125.0 mm SL), rio Araguaia, 10°35’S 50°34’W, Santa Terezinha, Mato Grosso, Oct 1964, H.A. Britski. MZUSP 14431 (2, paratypes, 92.5–112.5 mm SL), rio Tocantins, at mouth of rio Lajeado, Tocantinópolis, Goiás, J.C. Garavello et al. MZUSP 81679 (1, 131.1 mm SL), rio Tocantins, immediately below UHE Tucuruí, Tucuruí, Pará, 1999-2000, Equipe CPA-Eletronorte. Leporinus vanzoi : MZUSP 21833 (holotype, 66.5 mm SL), rio Tapajós at Cachoeira Lombo de Anta, 4°26’S 56°14’W, Itaituba, Pará, 6 Nov 1970, Expedição Permanente da Amazônia. MZUSP 87254 (8, paratypes, 54.0–66.0 mm SL), rio Tapajós at Cachoeira Lombo de Anta, 4°26’S 56°14’W, Itaituba, Pará, 6 Nov 1970, Expedição Permanente da Amazônia. MZUSP 92712 (2, 77.7– 94.9 mm SL), rio Tapajós at Pimental, 4°34’15’’S 56°15’39’’W, Itaituba, Pará, 11 Nov 2006, J.L. O. Birindelli & L.M. Sousa.

Figures

FIGURE 1. Leporinus britskii, a- INPA 33711, 102.5 mm SL, rio Jamanxim; b- holotype, MZUSP 109771, 88.9 mm SL, rio Jamanxim; c- MZUSP 97279, 43.4 mm SL, rio Jamanxim; d- MZUSP 102047, 28.2 mm SL, rio Jari; e- MZUSP 103484, 98.9 mm SL, rio Jari; f- MZUSP 103484, 95.1 mm SL, rio Jari. Relative size of specimens preserved.

FIGURE 2. Leporinus britskii, photographed live, a. MZUSP 97279, 100.4 mm SL, rio Jamanxim, near Castelo dos Sonhos, 8 ° 11 ’ 4 ’’ S 55 ° 21 ’ 28 ’’ W, Novo Progresso, Pará, Brazil (photo by Mark Sabaj Pérez); b. MZUSP 103484, 99.5 mm SL, rio Iratapuru, tributary of rio Jari, 0 ’ 33 ’ 59 ’’ S 52 ° 34 ’ 40 ’’ W, Laranjal do Jari, Amapá, Brazil.

FIGURE 3. Distribution map for Leporinus britskii. Star indicates the type locality.