Astyanax procerus Lucena, Castro & Bertaco, 2013

de Lucena, Carlos A. S., Castro, Jonas Blanco & Bertaco, Vinicius A., 2013, Three new species of Astyanax from drainages of southern Brazil (Characiformes: Characidae), Neotropical Ichthyology 11 (3), pp. 537-552 : 541-544

Astyanax procerus Lucena, Castro & Bertaco , new species Figs. 4-5

Astyanax sp. 1 . - Becker et al., 2013: 82 (listed).

Holotype. MCP 47002, 101.8 mm SL, Brazil, Rio Grande do Sul State, Nicolau Vergueiro, arroio Quebra Dentes , 28º36’09”S 52º27’03”W, 19 Jan 1999, R. E. Reis, J. F. P. da Silva & E. H. L. Pereira.

Paratypes. Brazil, Rio Grande do Sul State, laguna dos Patos system. MCN 19584, 2, 54.3-63.9 mm SL, MCP 33427 , 39 (2, 56.4-68.4 mm SL, 1, 75.0 mm SL c&s), UFRGS 17098 , 2 , 48.8- 67.1 mm SL, rio das Antas, upstream of Cachoeirão, Nova Roma do Sul , 29º00’40”S 51º22’22”W, 1 Oct 2002, J. Latini, J. R. Gonçalves & V. Capatti. MCP 21258 , 8 , 1 , 84.0 mm SL, tissue ,

Color in alcohol. Dorsal and dorsolateral portions of head and body dark brown. Body with black, midlateral stripe (silvery in some specimens probably due to fixation) placed on one to one and half series of scales extending from the second humeral spot to caudal-fin base; narrowing between the second humeral spot and opercle (region between spots pale in some specimens). Midlateral body stripe slightly expanded dorsally and ventrally to caudal-fin base, forming small caudal spot; dark pigmentation present on middle caudal-fin rays. Two humeral spots. Anterior one, conspicuous, vertically elongate with superior portion somewhat wider. Second humeral spot large, occasionally faint, not ventrally surpassing lateral line. Fins with a few dispersed dark chromatophores ( Fig. 1 ).

Sexual dimorphism. Males with fine and delicate, bony hooks on pelvic-fin and anal-fin rays. One paired bony hook per lepidotrichia in last unbranched ray and from the first to eleventh to twelfth anal-fin branched rays; the first seven or eight on upper third portion of rays; the remaining restricted to distal portions of rays. Hooks on the pelvic-fin are distributed in first three or four branched rays. Gill glands box I-28 (3, 83.6-90.7 mm SL), arroio da Gringa ca. 12 km North of Dona Francisca dam, Agudo , 29º23’16”S 53º13’23”W, 23 Aug 1998, R. E. Reis, J. F. P. da Silva & V. A. Bertaco. MCP 21457 , 4 (2, 88.9-92.6 mm SL), arroio Trombudo, Dona Francisca, 29º31’30”S 53º20’45”W, 10 Oct 1998, R. E. Reis, J. F. P. da Silva & E. H. L. Pereira. MCP 21476 , 4 (3, 87.1-87.9 mm SL), rio Ferreira between Pinhal Grande and Itaúba, Pinhal Grande, 29º16’37”S 53º14’53”W, 11 Oct 1998, R. E. Reis, J. F. P. da Silva & E. H. L. Pereira. MCP 25513 , 2 , 88.9 -100.0 mm SL, 1, 78.0 mm SL c&s, arroio Quebra Dentes, Nicolau Vergueiro, 28º36’09”S 52º27’03”W, 19 Jan 1999, R. E. Reis, J. F. P. da Silva & E. H. L. Pereira. MCP 33592 , 1 , 91.4 mm SL, 1 c&s, 65.0 mm SL, Quaresma, near to rio das Antas, Antônio Prado, 28º52’46”S 51º19’12”W, 2003, J. Latini, J. R. Gonçalves & V. Capatti. MCP 33607 , 2 , 89.8-118.5 mm SL, rio das Antas, near mouth of rio Carreiro , Santa Barbara, 29º05’29”S 51º42’42”W, 6 Nov 2002, J. Latini, J. R. Gonçalves & V. Capatti. MCP 37787 , 2 , 56.9-58.5 mm SL, MCP 37788 , 2 , 81.2-92.1 mm SL, rio das Antas drainage, Monte Claro dam, Bento Gonçalves, 29º01’08”S 51º28’28”W, Aug 2004, J. Latini, J. R. Gonçalves & V. Capatti. MCP 37791 , 3 , 67.6-72.6 mm SL, rio das Antas, near mouth of rio da Prata, Nova Roma do Sul , 29º04’01”S 51º22’48”W, 14 Feb 2003, A. R. Cardoso & V. A. Bertaco. MCP 37792 , 2 (1, 92.9 mm SL), downstream of Cachoeirão, Caninana rapids, Nova Roma do Sul , 29º04’01”S 51º22’48”W, Aug 2004, J. Latini, J. R. Gonçalves & V. Capatti. MCP 43063 , 1, 101.2 mm SL, rio das Antas, Castro Alves dam, Nova Roma do Sul , 28º57’01”S 51º14’53’’W, Jan 2008, J. Latini, J. R. Gonçalves & V. Capatti. MCP 43108 , 1 , 109.0 mm SL, rio das Antas, Castro Alves dam, Nova Roma do Sul , 28º57’01”S 51º14’53’’W, Apr 2008, J. Latini, J. R. Gonçalves & V. Capatti. MCP 43517 , 2 , 95.4-101.2 mm SL, rio das Antas, Castro Alves dam, Nova Roma do Sul, 28º57’01”S 51º14’53”W, May 2008, J. Latini, J. R. Gonçalves & V. Capatti. MCP 47390 , 3 (2, 96.0- 98.3 mm SL), rio Guaporé at Paraíso, Guaporé, ca. 28º50’S 51º53”W, 9 Jul 1999, P. Azevedo, W. Taborda & E. Borsato.

Diagnosis. Astyanax procerus differs from all congeners inhabiting the rio Uruguay basin, laguna dos Patos and rio Tramandaí systems by the first humeral spot vertically elongate with upper portion wider portion narrow and curved, with a pronounced constriction at the junction of both portions (vs. present of oval shape spot with two brown vertical bars in humeral region in A. jacuhiensis , oval shape in A. laticeps and forming a uniform wedge in A. eigenmanniorum and A. henseli ), 18-23 branched anal-fin rays (vs. 18 or less in A. brachypterygium and A. cremnobates , 23 or more in A. aramburui , A. paris , A. saguazu , and A. stenohalinus ), two humeral spots (vs. one in A. eigenmanniorum , A. sp. aff. fasciatus , A. jacuhiensis , and A. laticeps ), by the presence of one maxillary teeth (vs. 2-5 in A. henseli ), and by the body depth, 38.3-46.0% (vs. smaller than 38% of SL in A. brachypterygium , A. cremnobates , A. obscurus , and A. xiru new species), maxillary teeth tri- to pentacuspid (vs. hexa- to heptacuspid in A. dissensus new species and A. ojiara ). Most similar to A. xiru in color pattern, differing by the pelvic-fin length (16.1-18.7% vs. 13.6-17.1% of SL), dorsal-fin length (24.1- 28.7% vs. 21.1-25.4% of SL), absence of bony hooks on the anal and pelvic fins of males (vs. presence). The following combination of characters distinguish A. xiru from all others species of the genus (including the species complex A. bimaculatus and A. scabripinnis ): the presence of two conspicuous humeral spots (first humeral spot vertically elongate with upper portion wider portion narrow and curved, with a pronounced constriction at the junction of both portions), a conspicuous wide lateral band, 18-23 branched anal-fin rays, 20-23 gill rakers on first branchial arch, 37-40 perforated lateral line scales, 5 scale rows between lateral line and anal-fin origin, outer row of premaxilla with pentacuspid teeth, inner premaxilla row with heptacuspid teeth, one maxillary tooth tri- to pentacuspid, the absence of hooks on fins of males, a conspicuous caudal spot, body depth 38.3-46.0% of SL, head length 23.8-26.6% of SL, anal-fin base length 23.4-29.8% of SL, pectoral-fin length 21.8-24.1% of SL, and interorbital width 28.5-34.9% of HL.

Description. Morphometric data summarized in Table 1. Body compressed and deep, with greatest body depth anterior to dorsal-fin origin. Dorsal profile of head straight or slightly convex from posterior nostril to tip of supraoccipital spine. Dorsal body profile convex from tip of supraoccipital spine to base of last dorsal-fin ray; straight from latter point to adipose fin origin. Ventral profile of body convex from vertical through posterior nostril to pelvic-fin origin, nearly straight to anal-fin origin, and posterodorsally slanted along anal-fin base. Caudal peduncle elongate, nearly straight to slightly concave in the dorsal and ventral margins.

Snout rounded from margin of upper lip to vertical through anterior nostrils. Head somewhat pointed anteriorly in lateral profile. Mouth terminal, jaw isognathous, Maxilla extending posteriorly to vertical through anterior margin of orbit, slightly curved.

Two tooth rows in premaxilla; outer row with 4(4), 5(16)*, or 6(9) pentacuspid teeth, central cusp longer; inner row with five teeth, gradually decreasing in length from the first to fourth, last distinctly smaller, with six to seven cusps; except the first teeth with asymmetric five cups and the last with five or six cusps, central cusp twice as long and broad as others cusps. Maxilla with one tooth bearing four or five cusps, central cusp longer. Dentary with nine to ten teeth. Five anteriormost dentary teeth decreasing gradually, penta- to hexacuspid; remaining four or five smaller, tetra-, tricuspid or, rarely, unicuspid. Central cusp in all teeth two to three times as long and broad as other cusps. All cusp tips slightly curved posteriorly towards inside mouth ( Fig. 5 ).

Dorsal-fin rays ii,8(1) or 9(29)*; first unbranched ray approximately half length of second ray. Distal margin of dorsal-fin nearly straight to somewhat convex. Dorsal-fin origin approximately at middle of SL. Adipose fin before to vertical through last anal-fin ray insertion. Anal-fin rays iiiv, 19(3), 20(8), 21(8), 22(8)*, or 23(3). First unbranched ray normally only apparent in c&s specimens. Anal-fin profile smoothly concave. Anal-fin origin posterior to vertical through base of last dorsal-fin ray. Pectoral-fin rays i,11(5), 12(15)*, or 13(5). Pectoral-fin tip reaching one scales before vertical through pelvic-fin insertion; in young specimens (ca. 50.0 mm SL) reaching the vertical through pelvic-fin insertion. Pelvic-fin rays i,6(1) or 7(29). Pelvic-fin origin slightly anterior to vertical through dorsal-fin origin. Pelvic-fin tip extend beyond the genital opening but not reach the anal-fin origin. Caudal fin forked, lobes similar in size, rounded, i,17,i (30) principal rays. Dorsal procurrent rays 12(2) and ventral procurrent rays 9(1), or 10(1).

Lateral line complete with 37(7), 38(19)*, 39(8), or 40(2) scales. Scale rows between dorsal-fin origin and lateral line 6(20), or 7(9); scale rows between lateral line and pelvic-fin origin 4(5)*, or 5(25). Predorsal scales 11(15), 12(13)*, 13(1), or 14(1) arranged in regular series. Scale rows around caudal peduncle 14(11), 15(13), or 16(6). Axillary scale on pelvic-fin origin extends posteriorly covering 2-3 scales. Scale sheath along anal-fin base 10-13 scales, in single series, covering base of anteriormost rays.

Precaudal vertebrae 18(2), or 19(1); caudal vertebrae 18(1), or 19(2); total vertebrae 36(1), 37(1), or 38 (1). Supraneurals 5(1), or 6(2). Gill-rakers upper branch 7(3), 8(21), or 9(6); lower branch 13(12)*, 14(19), or 15(3); total number 20(3), 21(9)*, 22(10), or 23(8).

Color in alcohol. Dorsal and dorsolateral portions of head and body dark brown. Dark chromatophores scattered on lateral portion of head, more densely concentrated on snout and anterior border of eye. Dorsal portion of body densely pigmented. Body with black, midlateral stripe extending from the second humeral spot to caudal-fin base; dark pigmentation present on middle caudal-fin rays. Midlateral body stripe slightly expanded dorsally and ventrally to caudal-fin base.Two humeral spots. Anterior one, conspicuous, vertically elongate with superior portion wider, located over fourth to fifth vertical series of scales, extending over two to three horizontal series of scales above lateral line; inferior portion of spot narrow and curved, sometimes with constriction at the junction with the upper portion, (one to two scales pigmented), extending over one to two horizontal series of scales below lateral line. Second humeral spot large, not ventrally surpassing lateral line, extending over three horizontal series and two to three vertical series of scales. Region between spots pale. Fins with dispersed dark chromatophores ( Fig. 4 ).

Sexual dimorphism. Secondary sexual characters were not found on examined specimens. Testes were observed in 15 specimens (MCP 37791, 72.6 mm SL, male, MCP 33592, 91.4 mm SL, female, MCP 33607, 118.5 mm SL, female and 89.8 mm SL, male. MCP 43517, 101.2 mm SL, female and 95.4 2 mm SL, male, MCP 21457, 92.6 mm SL, female and 88.9 mm SL, male, MCP 25513, 88.9 mm SL, female and 100.0 mm SL, male; MCP 21476, 87.1 mm SL, female, 87.5 mm SL, male, and, 87.9 mm SL male. MCP 37787, 58.5 mm SL, male and 56.9 mm SL, male). Not all males were mature. Gill glands ( Burns & Weitzman, 1996) were not found on first gill arch in all specimens.

Distribution. Astyanax procerus is known from the upper and middle rio Taquari-Antas and rio Jacuí, laguna dos Patos system, Rio Grande do Sul, Brazil ( Fig. 6 ).

Etymology. The specific epithet procerus from Greek, means tall, in reference the high body depth of the species. An adjective in apposition.

Figures

Fig. 4. Astyanax procerus, new species, MCP 47002, 101.8 mm SL, holotype, arroio Quebra Dentes at Quebra Dentes, Nicolau Vergueiro, Rio Grande do Sul, Brazil.

Fig. 5. Astyanax procerus, new species, MCP 25513, 78.0 mm SL, paratype, upper and lower jaws teeth, left side, lateral view.Scale bar = 1 mm.

Fig. 1. Astyanax dissensus, new species, MCP 47000, 65.1 mm SL, holotype, arroio Candiota, rio Jaguarão drainage, Candiota, Rio Grande do Sul, Brazil.

Fig. 6. Map of southern Brazil and Uruguay, showing the distribution of the material examined of Astyanax procerus. Some symbols represent more than on lot or locality. Black circle = type locality.