Charax rupununi Eigenmann, 1912

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 : 221-222

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Charax rupununi Eigenmann, 1912


Charax rupununi Eigenmann, 1912  

Fig. 24 View Fig

Charax rupununi Eigenmann, 1912: 402   (original description, type locality: Guyana, Rupununi River ). -Henn, 1928: 70 (listed in type catalog). - Ibarra & Stewart, 1987: 22 (listed in type catalog). - Lucena, 1987: 50 (diagnosis, description; comparisons; distribution). - Lucena, 1989: 104 (in key to species). - Lucena & Menezes, 2003: 201 (maximum length; distribution).

Charaxodon rupununi, Fernandez-Yepez, 1947   (in key to species).

Diagnosis. Charax rupununi   is distinguished from congeners with the lateral line complete and the dorsal region

of the body anterior to the dorsal fin scaled except for a small naked area anterior to the dorsal-fin origin in having 42-44 perforated scales along the lateral line (vs. 50-65 perforated scales on the lateral line in C. tectifer   , C. metae   , C. delimai   , C. metae   , C. caudimaculatus   , C. notulatus   , C. apurensis   , C. macrolepis   , C. michaeli   , C. pauciradiatus   , C. gibbosus   , C. niger   , and C. leticiae   ). Charax rupununi   differs from C. hemigrammus   , C. condei   and C. stenopterus   by having the lateral line complete and the dorsal region of the body anterior to the dorsal fin, except for a small naked area anterior to dorsal-fin origin scaled (vs. the lateral line incomplete and scales lacking on the dorsal region of the body anterior to the dorsal fin).

Description. Table with complete morphometric data not presented since only the poorly preserved holotype and another more recently collected specimen of this rare species were available for study. Body elongate, small compared to congeners (38-45 mm SL), compressed and comparatively low. Greatest body depth slightly in advance of dorsal-fin origin. Dorsal profile of head and body slightly convex from tip of snout to anterior region of fontanel, slightly concave from that point to base of supraoccipital spine, slightly convex from that point to dorsal-fin origin, nearly straight along dorsalfin base and from end of dorsal-fin base to caudal peduncle and very slightly concave along caudal peduncle. Ventral profile of head and body convex from tip of lower jaw to analfin origin, nearly straight to slightly concave 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 slightly beyond vertical through middle of orbit.

Dorsal-fin rays ii, 9 (2) posteriormost ray unbranched. Adipose fin present. Unbranched anal-fin rays iv, branched rays 44-46. Pectoral-fin rays i, 12-15. Tips of longest pectoralfin rays extending beyond pelvic-fin origin, but falling short of vertical through middle of pelvic-fin length. Pelvic-fin rays i, 7 (2). Tips of longest pelvic-fin rays reaching slightly beyond anal-fin origin. Principal caudal-fin ray count 10/9 (2).

Lateral line complete; perforated scales 42-44. Horizontal scale rows from dorsal-fin origin to lateral line 13 (1). Horizontal scale rows from pelvic-fin origin to lateral line 7 (1). Horizontal scale rows from anal-fin origin to lateral line eigth and nine. Scale rows around caudal peduncle 12 (1). No scales anteriorly along anal-fin base.

Premaxillary with one anterior large conical tooth followed by set of smaller conical teeth, one large conical teeth and six smaller conical teeth (1). Total number of premaxillary teeth 14 (1). Maxillary teeth conical, 41-42. Dentary with anterior row including six conical teeth and posterior row with 21 conical teeth (1). Ectopterygoid conical teeth 14 (1).

Vertebrae 32 (1). Gill-rakers on lower limb of first gill-arch 8 (1). Branchiostegal rays 4; 3 rays originating from anterior cerathyal and 1 from posterior ceratohyal (1).

Color in alcohol. Most of original coloration not preserved. Body pale, slightly darker dorsally. Scattered dark chromatophores all over body. Roundish dark humeral blotch extending about two scales horizontally and one scale vertically. Concentration of dark chromatophores on caudal base forming oval-shaped blotch extending over bases of median caudal-fin rays. Dorsal portions of head, snout and tip of lower with scattered dark chromatophores. Opercle with scattered dark chromatophores. All fins hyaline.

Distribution. The two known specimens of this species have been collected respectively in Rupununi, Guyana and Lago Jacaré, rio Trombetas, Brazil ( Fig. 7 View Fig ).

Specimens examined. FMNH 53663 View Materials , holotype, 45 mm SL, Guyana: Rupununi , 4°21’43"N 59°09’30"W GoogleMaps   ; MZUSP 27937 View Materials , 1 View Materials , 38 mm SL, Brazil, Pará , lago Jacaré, rio Trombetas, 1°20’S 56°51’W GoogleMaps   . Previously included in Lucena (1987).