Charax niger Lucena, 1989,

Menezes, Naércio A. & de Lucena, Carlos Alberto S., 2014, A taxonomic review of the species of Charax Scopoli, 1777 (Teleostei: Characidae: Characinae) with description of a new species from the rio Negro bearing superficial neuromasts on body scales, Amazon basin, Brazil, Neotropical Ichthyology 12 (2), pp. 193-228: 215-217

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Charax niger Lucena, 1989


Charax niger Lucena, 1989 

Figs. 19-20View Fig

Charax niger Lucena, 1989: 99  [original description, type locality: Brazil, Amapá, rio Amapá (river channel), Cachoeira Grande ]. -Oyakawa, 1996: 455 (listed in catalog). - Lucena & Menezes, 2003: 201 (maximum length; distribution).

Diagnosis. Charax niger  differs from C. caudimaculatus  and C. notulatus  in the orbital diameter (30.1-38.4% vs. 25-28.5% of HL, Fig. 4). Charax niger  can be distinguished from C. caudimaculatus  and C. notulatus  in the scale rows around the caudal peduncle (17-18 vs. 20-22), from C. michaeli  by the number of scale rows from the dorsal-fin origin to the lateral line (15-16 vs. 18-20), from C. pauciradiatus  by the number of the scale rows from the dorsal-fin origin to the lateral line (15- 16 vs. 13-14), from C. gibbosus  by the number of predorsal scales (52-68 vs. 38-45) and the absence (vs. presence) of ectopterygoid teeth) and from C. leticiae  in having the humeral spot distance (35.4-37.8% of SL, Fig.3View Fig, with 5-6 transverse scale rows in space from the humeral spot to the supracleithrum vs. the humeral spot distance, 38.5-44.8% of SL, with 8-10 transversal scale rows from the humeral spot to the supracleithrum). Charax niger  differs from C. hemigrammus  , C. condei  , and C. stenopterus  by having the lateral line complete (vs. lateral line incomplete), from C. rupununi  by the number of scales around the caudal peduncle (17-18 vs. 12) and from C. tectifer  , C. metae  , and C. delimai  in 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) and ectopterygoid teeth absent (vs. ectopterygoid teeth present).

Description. Morphometrics of examined specimens presented in Table 11. Body elongate, moderately large (40- 127 mm SL), compressed and moderately deep. Greatest body

from MZUSP 31137, 81137, 81266, 81193, 87354, 87355.

depth slightly in advance of dorsal-fin origin. Dorsal profile of head and body straight from tip of snout to anterior portion of fontanel, slightly concave from that point to base of supraoccipital spine, 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 profile of head and body 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 about vertical through posterior border of pupil.

Dorsal-fin rays ii, 9-10, 9, posteriormost ray unbranched. Adipose fin present. Unbranched anal-fin rays iv or v, usually iv, branched rays 44-52, 48.2. Sexually mature males with hooks on anal-fin ( Fig. 20); one male specimen (MZUSP 33424, 105 mm SL) with bilateral tiny hooks on posterior anterior 11 rays, number of hooks varying considerably, but posteriormost rays with fewer hooks: third unbranched ray with 28, fourth unbranched ray first branched ray with 22, second with 28, third with 19, fourth with 17, fifth with 17, sixth with 6, seventh with 7, eighth with 8, nineth with 9, tenth with 6, and eleventh with 3. Pectoral-fin rays i, 12-17, 14. Tips of longest pectoral-fin rays reaching slightly beyond middle of pelvic-fin length. Pelvic-fin rays i, 7. No hooks on pelvicfin rays of sexually mature males. Tips of longest pelvic-fin rays reaching vertical through bases of second and fourth branched anal-fin rays. Principal caudal-fin ray count 10/ 9 in all specimens.

Lateral line complete; perforated scales 53-60, 56.3. Horizontal scale rows from dorsal-fin origin to lateral 15-16, 15.7. Horizontal scale rows from pelvic-fin origin to lateral line 9-11, 9.8. Scale rows from anal-fin origin to lateral line 11-14, 12. Predorsal scales 52-68, 58. Scale rows around caudal peduncle 17-18, 17.8. Scale row along anal-fin base extending for about 2 /


of fin base.

Premaxillary with one anterior canine-like tooth followed by set of smaller conical teeth and another canine-like tooth followed by one or two small conical teeth. Total number of premaxillary teeth 9-16, 13. Maxillary teeth conical, 47-77, 67.2, larger specimens usually with higher counts. Dentary with one canine-like tooth followed by 3-6, 4.4 conical teeth, another canine-like tooth and a posterior row of 18-36, 28.2 conical teeth.

Gill-rakers on lower limb of first gill-arch 8-10, 8.4. Branchiostegal rays 4; 3 rays originating from anterior ceratohyal and 1 from posterior ceratohyal.

Color in alcohol. Body pale to light yellow, slightly darker dorsally than on lateral and ventral portions. Body lighter ventrally with scattered dark chromatophores especially posteriorly. Dorsal part of head, snout and tip of lower jaw darker than remainder of head; dark chromatophores spreading over first, second, fourth, fifth and sixth infraorbitals, between second and third infraorbitals as subocular blotch extending ventrally to ventral border of preopercle, median portion of

N. A. Menezes & C. A. S. de Lucena 217

lower jaw and median portion of maxilla. Scattered dark chromatophores on preopercle, and opercle. Irregularly shaped vertically elongate dark blotch at humeral blotch encompassing about 3 to 4 scales horizontally and 4 to 5 vertically. Triangular dark blotch on caudal base, dark chromatophores of posterocentral portion extending over bases of median caudal-fin rays. Darker lines of chromatophores along miosepta of epaxial muscles above lateral line and miosepta of hypaxial muscles below lateral line; more conspicuous on body region posterior to vertical through termination of dorsal-fin base, forming V-shaped patterns. All fins hyaline with scattered dark chromatophores more visible on the interradial membranes. Inconspicuous clear stripe dorsally below bases of anterior anal-fin rays, approaching and extending very close to anal-fin base from about middle to end of fin base. Anterior portion of first and second unbranched dorsal-fin rays and first unbranched rays of pectoral and pelvic fins darker than remaining rays.

Sexual dimorphism. Females lack tiny anal-fin hooks described above for males and usually reach on average larger body sizes than males. The only four males available (MZUSP 33430, MZUSP 33431, MZUSP 38303, and MZUSP 33424) have fully developed testes and anal-fin hooks respectively at 83.5, 104, 101, and 105 mm SL. Females with developed ovaries (MZUSP 33430, MZUSP 33431, MZUSP 33424, and MZUSP 3830) were fully mature at sizes between 103 and 127 mm SL. Distribution. Charax niger  is known from rio Tocantins, rio Amapá and tributaries; rio Negro and tributaries; and a tributary of rio Preto da Eva, Brazil ( Fig. 7View Fig).

Specimens examined. Brazil, Amazonas: MZUSP 31137View Materials, 1View Materials, 70 mm SL, Anavilhanas, rio Negro , 3°06’53"S 60°00’14"WGoogleMaps  ; MZUSP 81137View Materials, 1View Materials, 79.3 mm SL, rio Tiquié, between communities Caruru and Boca de Sal , 0°16’N 69°54’WGoogleMaps  , rio Negro drainage  ; MZUSP 81266View Materials, 1View Materials, 79.3 mm SL, community of Caruru, rio Tiquié, rio Negro drainage, 0°16’N 69°54’WGoogleMaps  ; MZUSP 81193View Materials, 3View Materials, 76-96 mm SL, community of Caruru, rio Tiquié, rio Negro drainage, 0°16’N  69°54"W; MZUSP 87354View Materials, 1View Materials, 40 mm SL, Recanto do Buriti, Rio Preto da Eva, rio Negro drainage, 2°41’58"S 59°54’WGoogleMaps  ; MZUSP 87355View Materials, 1View Materials, 95 mm SL, Rio Preto da Eva, igarapé Agripino, tributary of rio Preto da Eva , 2°43’59"S 59°40’48"WGoogleMaps  . MZUSP 33427View Materials, 6View Materials, 97-122 mm SL, Amapá, Cachoeira Grande , canal of river, not precisely located. Tocantins  : UNT 9042View Materials, 1View Materials, 83 mm SL, riacho afluente do rio Santa Tereza, Sucupira , 12º15‘0"S 48º41’01"WGoogleMaps  ; UNT 166View Materials, 2View Materials, 62-68 mm SL  , UNT 2563View Materials, 1, 107 mm SL, Lagoa Pedra do Santo, Brejunho de Nazaré , 11º01‘S 48º34‘WGoogleMaps  .