Charax awa, Guimaraes, Erick Cristofore, Brito, Pamella Silva De, Ferreira, Beldo Rywllon Abreu & Ottoni, Felipe Polivanov, 2018

Guimaraes, Erick Cristofore, Brito, Pamella Silva De, Ferreira, Beldo Rywllon Abreu & Ottoni, Felipe Polivanov, 2018, A new species of Charax (Ostariophysi, Characiformes, Characidae) from northeastern Brazil, Zoosystematics and Evolution 94 (1), pp. 83-93 : 83-87

Charax awa sp. n. Fig. 1

Charax gibbosus [non Charax gibbosus (Linnaeus, 1758)]: Martins and Oliveira 2011: 196-197.

Charax sp. - Martins and Oliveira 2011:196-197.

Holotype.

CICCAA 00752, 101.3 mm SL, Brazil: Maranhão State: Alto Alegre do Pindaré municipality: Igarapé Mineirão, Rio Mearim basin, 3°42 ’26” S, 45°56 ’5” W; Guimarães E. C. and Costa C.H.; 03 Dec. 2015.

Paratypes. All from Maranhão State, Brazil: CICCAA 00248, 9, 47.7-90.6 mm SL; CICCAA 00249, 6 (C&S), 42.6-73.8 mm SL; CICCAA 00754, 2, 55.2-68.7 mm SL; collected with holotype. CICCAA 00753, 1 (C&S), 41.4 mm SL, Rio Zutiua (Rio Mearim basin), Santa Inês municipality, 3°43 ’48” S, 45°35 ’7” W; Guimarães E. C. and Costa C.H.; 03 Dec 2015.CICCAA 00766, 1 (C&S), 78.5 mm SL, Rio Zutiua (Rio Mearim basin), Santa Inês municipality, 3°43 ’48” S, 45°35 ’7” W; Guimarães E. C. and Costa C.H.; 03 Dec 2015. CICCAA 00755, 1, 59.8 mm SL; stream at the Santa Inês municipality (Rio Mearim basin), Santa Inês municipality, 3°40 ’48” S, 45°19 ’51” W; Guimarães E. C. and Costa C.H.; 03 Dec 2015.CICCAA 00896, 2, 40.2-48.8 mm SL stream Arapapá (Rio Mearim basin), Alto Alegre municipality; 3°42 ’30” S, 46°0 ’19” W; Guimarães E. C. and Brito P. S; 15 Ago 2017.CICCAA 00765, 11, 44.4-68.3 mm SL Lirio stream (Rio Mearim basin), Alto Alegre municipality; 3°38 ’56” S, 45°46 ’18” W; Guimarães E. C. and Brito P.S; 15 Ago 2017.CICCAA 00764, 5, 68.4-89.3 mm SL, Olho d’água dos Carneiros (Rio Mearim basin), Santa Inês municipality; 3°43 ’0” S, 45°28 ’36” W; Guimarães E. C. and Brito P.S; 11 Ago 2017. CICCAA 00898, 1, 62.2 mm SL, stream at Miranda do Norte municipality (Rio Mearim basin), 3°31 ’30” S, 44°35 ’6” W; Guimarães E. C. and Brito P.S.; 13 Ago 2017.

UFRJ 11696, 2, 69.9-70.6 mm SL stream Arapapá (Rio Mearim basin), Alto Alegre municipality; 3°42 ’30” S, 46°0 ’19” W; Guimarães E. C. and Brito P.S; 15 Ago 2017. MCP 52700, 4, 45.9-75.1 mm SL Arapapá stream (Rio Mearim basin), Alto Alegre municipality; 3°42 ’30” S, 46°0 ’19” W; Guimarães E. C. and Brito P.S; 15 Ago 2017. CPUFMA 98859, 40, 52.2-120.0 mm SL, Rio Turiaçu, (Rio Turiaçu basin), Santa Helena municipality; 2°27 ’35” S, 45°30 ’42” W; Piorski et al. 8 Ago 1998. CPUFMA 001747, 18, 76.9-117.3 mm SL, Rio Turiaçu, (Rio Turiaçu basin), Santa Helena municipality; 2°27 ’35” S, 45°30 ’42” W; Piorski et al. 17 Abr 2000. CPUFMA 112036, 4, 88.5-88.7 mm SL, Rio Munim, Chapadinha municipality; 3°50 ’19” S, 43°19 ’46” W; Nunes et al. 8 Jul 2011. CPUFMA 98136, 3, 85.2-93.7 mm SL, Lago de Viana (Rio Mearim basin), Cajari municipality; 3°22 ’48” S, 45°2 ’57” W; Piorski and Pereira, 17 Mar 1998. CPUFMA 98135, 3, 85.6-91.4 mm SL, Lago de Viana (Rio Mearim basin), Cajari municipality; 3°18 ’54” S, 45°1 ’40” W; Piorski and Pereira, 17 Mar 1998. CPUFMA 98137, 1, 88.2 mm SL, Lago de Viana (Rio Mearim basin), Viana municipality; 3°15 ’9” S, 45°4 ’48” W; Piorski and Pereira, 14 Mar 1998. CPUFMA 97130, 1, 91.3 mm SL, stream Engenho (Rio Mearim basin), Viana municipality; 3°12 ’26” S, 44°58 ’5” W; Piorski and Pereira, 6 Dez 1997.

Non type material.

All from Maranhão State, Brazil: CPUFMA 98861, 24, 83.5-120.0 mm SL, Rio Turiaçu, (Rio Turiaçu basin), Santa Helena municipality; 2°27 ’35” S, 45°30 ’42” W; Piorski et al. 8 Ago 1998. CPUFMA 98862, 23, 79.4-119.1 mm SL, Rio Turiaçu, (Rio Turiaçu basin), Santa Helena municipality; 2°27 ’35” S, 45°30 ’42” W; Piorski et al. 14 Ago 1998. CPUFMA 00863, 25, 68.0-113.1 mm SL, Rio Turiaçu, (Rio Turiaçu basin), Santa Helena municipality; 2°27 ’35” S, 45°30 ’42” W; Piorski et al. 21 Ago 2000. CPUFMA 00864, 43, 72.3-113.9 mm SL, Rio Turiaçu, (Rio Turiaçu basin), Santa Helena municipality; 2°27 ’35” S, 45°30 ’42” W; Piorski et al. 16 Out 2000. CPUFMA 00865, 11, 82.3-114.2 mm SL, Rio Turiaçu, (Rio Turiaçu basin), Santa Helena municipality; 2°27 ’35” S, 45°30 ’42” W; Piorski et al. 21 Ago 2000. CPUFMA 00866, 31, 82.6-110.3 mm SL, Rio Turiaçu, (Rio Turiaçu basin), Santa Helena municipality; 2°27 ’35” S, 45°30 ’42” W; Piorski et al. 15 Out 2000. CPUFMA 00867, 16, 88.7-102.12 mm SL, Rio Turiaçu, (Rio Turiaçu basin), Santa Helena municipality; 2°27 ’35” S, 45°30 ’42” W; Piorski et al. 22 Jun 2000.

Diagnosis.

Charax awa sp. n. can be distinguished from C. apurensis Lucena, 1987, C. condei ( Géry & Knöppel, 1976), C. delimai Menezes & Lucena, 2014, C. gibbosus (Linnaeus, 1758), C. hemigrammus (Eigenmann, 1912), C. leticiae Lucena, 1987, C. macrolepis (Kner, 1858), C. metae Eigenmann, 1922, C. michaeli Lucena, 1989, C. niger Lucena, 1989, C. pauciradiatus ( Günther, 1864), C. stenopterus (Cope, 1894) C. tectifer (Cope, 1870) by the orbital diameter (22.1-28.5% HL vs. 29.6-38.4% HL combined) (Fig. 2). Charax awa sp. n. differs from C. caudimaculatus Lucena, 1987 by the possession of a longer snout (snout length 23.3-32.8% HL vs. 20.3-22.8% HL); from C. notulatus Lucena, 1987 by the number of scales around the caudal peduncle (15-18 vs. 20-22) and by having more vertebrae (35 vs. 32). Furthermore, Charax awa sp. n. can be distinguished from C. condei , C. hemigrammus and C. stenopterus by having the lateral line complete (vs. incomplete); from C. delimai , C. metae and C. tectifer by having a toothless ectopterygoid (vs. presence of teeth on ectopterygoid) and having the anal-fin origin always anterior to the vertical through the dorsal-fin origin (vs. anal-fin origin on, or slightly posterior to the vertical through the dorsal-fin origin); from C. condei , C. delimai , C. hemigrammus , C. metae , C. pauciradiatus and C. stenopterus by the number of scale rows from the pelvic-fin origin to the lateral line (11-12 vs. 6-10 combined); from C. pauciradiatus by having more scale rows from the dorsal-fin origin to the lateral line (15-18 vs. 13-14). It can be distinguished from C. niger by having 8-10 transverse scale rows in space from the humeral spot to the supracleithrum (vs. 5-6); from C. condei , C. delimai , C. metae , C. rupununi Eigenmann, 1912 by the number of scale rows around the caudal peduncle (15-18 in C. awa sp. n. vs. 12-14 combined in C. condei and C. rupununi , 19-21 combined in C. delimai and C. metae ). Finally, it differs from C. leticiae by having the maxilla extending to a vertical line posterior to pupil, near the posterior orbital margin (vs. maxilla extending slightly beyond vertical through middle of pupil) and from humeral spot distance (35.8-38.0 % SL vs. 39.0-44.0 % SL).

Description. Morphometric data are presented in Tables 1 and 2. Body moderately large (40.2-120.0 mm SL), compressed and moderately deep; greatest body depth slightly in advance of dorsal-fin origin. Dorsal profile of head and body slightly convex on tip of snout, approximately straight from posterior border of posterior nostril to vertical line through posterior border of pupil, concave from that point to about half of distance between pupils and posterior margins of preopercle, strongly convex from that point to dorsal-fin origin, nearly straight along dorsal-fin base and from end of dorsal-fin base to caudal peduncle and slightly concave along caudal peduncle. Ventral pro file of head and trunk convex from tip of lower jaw to anal-fin origin, nearly straight along anal-fin base and slightly concave from end of anal-fin base to beginning of procurrent rays. Snout pointed. Lower jaw included in upper jaw when mouth closed. Maxilla extending to a vertical line posterior to pupil, near the posterior orbital margin. Small triangular posteriorly directed projection at intersection between dorsal and posterior margins of hyomandibular ( Mattox and Toledo-Piza 2012: figs 24A, 25B).

Dorsal-fin rays ii, 9 (72). Dorsal-fin pterygiophores 10 (8); first dorsal-fin pterygiophore between 4th and 5th vertebrae. Adipose fin present. Unbranched anal-fin rays iv (74) or v (1), branched rays 46 (4), 47 (5), 48 (10), 49 (13), 50 (9), 51 (6), 52 (13), 53 (5), 54 (2) or 56 (1). Anal-fin pterygiophores 46 (2), 47 (2), 48 (1), 49 (2) or 50 (1); first anal-fin pterygiophore between 7th and 8th vertebrae. Pectoral-fin rays i, 13 (3) or 14 (22). Tips of longest pectoral-fin rays reaching slightly beyond middle of pelvic-fin length. Pelvic-fin rays i, 7 (64) or i, 8 (2). Axilar scale on pelvic fin absent. Tips of longest pelvic-fin rays reaching anal-fin rays, between bases of second to seventh branches. Principal caudal-fin ray count 10/9 (59). Dorsal procurrent caudal-fin rays 12 (1), 14 (2), 15(1), 16 (2) or 17 (2). Ventral procurrent caudal-fin rays 7 (3), 8 (2), 9 (1), 1 (10) or 11 (1).

Ventral-most longitudinal series of scales on each side of trunk overlapping one another, delimiting longitudinal gap on region anterior to anus. Scale sheath along anal-fin base. Scales on caudal fin restricted to base of rays. Lateral line complete; perforated scales 53 (1), 54 (3), 55 (8), 56 (10), 57 (4), 58 (2), 59 (4), 60 (7), 61 (4), 62(3) or 63 (1). Horizontal scale rows between dorsal-fin origin and lateral line 15 (27), 16 (20), 17 (5) or 18 (3). Horizontal scale rows between pelvic-fin origin and lateral line 11 (66) or 12 (4). Horizontal scale rows between anal-fin origin and lateral line 12 (2), 13 (37), 14 (16), 15 (7) or 16 (1). Scale rows around caudal peduncle 15 (4), 16 (26), 17 (13) or 18 (3). Scale row along anal-fin base, extending for about two thirds of fin base. Predorsal scales 49 (1), 50 (6), 52 (9), 53 (5), 54(7), 55(3), 56(3), 57 (1), 58 (1), 59 (1), 60 (1), 62 (4), 63 (2), 64 (1), 66 (1), 68 (2). Transverse scale rows between humeral spot and supracleithrum 8 (57), 9 (16) or 10 (1).

Premaxilla and dentary with two canine-like teeth and remaining teeth conical. Maxilla with all teeth conical. Premaxilla with one anterior canine-like tooth followed by set of smaller conical teeth, another canine-like tooth placed on posterior portion of bone, followed by one or two small conical teeth (Fig. 2). Total number of premaxillary teeth 13 (4), 14 (3) or 15 (1). Maxilla with 52 (1), 55 (4), 58 (2) or 60 (1) teeth. Dentary with one canine-like tooth followed by 3-4 conical teeth, another canine-like tooth followed by a posterior row of 16 (3), 18 (4) or 19 (1) conical teeth (Fig. 2).

Ectopterygoid and metapterygoid without teeth. Gill-rakers on lower limb of first gill-arch 13 (2), 14 (3). Branchiostegal rays 3 (1) or 4 (7). Supraneurals 4 (8); first supraneural inserted posterior to neural spine of 4th centrum, and last supraneural inserted anterior to first dorsal-fin pterygiophore. Precaudal vertebrae 12 (8). Caudal vertebrae 23 (8). Total vertebrae 35 (8). Pleural rib pairs 11 (8). Pre- and postzygapophyses minute, approximately triangular in shape, and positioned somewhat parallel to neural zygapophysis of adjacent vertebra (e.g. Mattox and Toledo-Piza 2012: fig. 32A).

Color in alcohol

(Fig. 1A). Body pale yellow to light yellow, slightly darker dorsally. Both extreme dorsal and ventral regions of trunk with scattered dark chromatophores. Inconspicuous approximately rounded or slightly elliptical dark brown humeral blotch, extending about three to four scales horizontally and about five vertically. Dorsal part of head, snout, circumorbital region and opercle darker than rest of head. Scattered dark chromatophores on tip of snout and suborbital region. V-shaped lines of chromatophores over myosepta along epaxial and hypaxial muscles, more visible on mid-posterior portion of body. Inconspicuous, approximately triangular shaped dark blotch on caudal-fin base, with posterior dark chromatophores. Inconspicuous clear stripe at anal-fin base. All fins hyaline, or light brown at base, with scattered dark chromatophores more visible on interradial membranes. Anterior portion of first to third unbranched rays of dorsal and first unbranched rays of pectoral and pelvic-fin rays darker than remaining rays.

Color in life

(Fig. 1B). Color pattern in life similar to coloration of preserved specimens. Body silver on, anterior portion, and silver to hyaline on posterior portion. Anterior and dorsal portions of trunk darker, and sides of head darker than rest of body. Humeral and caudal-fin base blotches inconspicuous. Dorsal margin of trunk with conspicuous dark brown chromatophores. Purple longitudinal stripe along mid-portion of flank, extending posteriorly to anterior margin of caudal-fin base. Fins hyaline, with scattered dark brown or black chromatophores, more visible on interradial membranes.

Sexual dimorphism.

No apparent sexual dimorphism.

Distribution.

Charax awa is known from the Rio Mearim, Rio Munim and Rio Turiaçu basins, Maranhão state, northeastern Brazil (Fig. 3).

Remarks.

The new species herein described differs from its geographically closely distributed congeners, C. leticiae , C. niger , and C. pauciradiatus , with records in the Lower Amazon, Capim, upper Itapecuru and Tocantins river basins (Fig. 4), mainly by the horizontal orbital diameter (see diagnosis section). In addition, C. awa sp. n. can be distinguished from C. leticiae by having the maxilla extending to a vertical line posterior to pupil, near posterior orbital margin while C. leticiae shows the maxilla extending slightly beyond vertical through middle of pupil and by humeral spot distance (32.1-38.0 % SL vs. 39.0-44.0 % SL). It can be distinguished from C. pauciradiatus by possessing 11-12 scale rows from the pelvic-fin origin to the lateral line and 15-18 scale rows from the dorsal-fin origin to the lateral line, while C. pauciradiatus possess 6-10 and 13-14, respectively, and differs from C. niger by having 8-10 transverse scale rows in space from the humeral spot to the supracleithrum, while C. niger possess 5-6. Moreover, it differs from C. pauciradiatus and C. niger by the absence of bony hooks on anal and pelvic-fins rays of adult males. This last character is emphasized in the discussion section.

In addition, new species herein described differs from C. gibbosus , a species incorrectly identified for the same area of C. awa sp. n. by the following features:

Charax awa sp. n. possesses a toothless ectopterygoid, absence of bony hooks on anal-fin rays of mature males, 8-10 transverse scales rows between the humeral spot and the suprecleithrum and 49-68 predorsal scales; while C. gibbosus has teeth on ectopterygoid, bony hooks on anal-fin rays of mature males, 5-6 transverse scales rows between the humeral spot and the suprecleithrum, and 38-45 predorsal scales.

Etymology.

The specific epithet honors the term Awá, from Tupi-guarani, meaning "man, people, person", used by the native tribe Guajá, from the Maranhão state, for their self-denomination.