Charax macrolepis (Kner, 1858)

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 : 209-211

Charax macrolepis (Kner, 1858)

Fig. 15

Epicyrtus macrolepis Kner, 1858: 167 (original description, type locality: Brazil, State of Mato Grosso, rio Guaporé ).

Charax macrolepis, Lucena, 1987: 42 (nomenclatural notes; diagnosis; description; comparisons; distribution; lectotype designation). -Lucena, 1989: 104 (in key to species). -Lucena & Menezes, 2003: 201 (maximum length; distribution).

Diagnosis. Charax macrolepis and C. apurensis are the only species belonging in the group with an orbital diameter 30.1-38.4% of HL ( Fig. 4 ) (vs. orbital diameter 25-28.5% of HL in C. caudimaculatus and C. notulatus ) that have 20-22 scale rows around caudal peduncle (vs. 16-19 in C. michaeli , C. pauciradiatus , C. gibbosus , C. niger , and C. leticiae ). Charax macrolepis additionally 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 (20-21 vs. 12) and perforated scales on the lateral line (63-65 vs. 42-44). Charax macrolepis can be further distinguished from C. tectifer , C. metae , and C. delimai by having the anal-fin origin always anterior to the vertical through the dorsal-fin origin (vs. the anal-fin origin on the vertical or slightly posterior to, the dorsal-fin origin) and the ectopterygoid teeth absent (vs. ectopterygoid teeth present).

Description. Morphometrics of examined specimens presented in Table 8. Body elongate, moderately large (65- 94 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, straight from posterior border of posterior nostril to vertical through posterior border of pupil, slightly concave from that point to base of supraoccipital spine, 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 above 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 slightly beyond vertical through middle of orbit.

Dorsal-fin rays ii, 9 in all specimens, posterior most ray unbranched. Adipose fin present. Unbranched anal-fin rays iv or v, usually iv, branched rays 48-52, 50. Pectoral-fin rays i, 13-16, 14.7. Tips of longest pectoral-fin rays reaching slightly beyond middle of pelvic-fin length. Pelvic-fin rays i, 7. Tips of longest pelvic-fin rays reaching to vertical between bases of second to sixth branched anal-fin rays. Principal caudal-fin ray count 10/ 9 in all specimens.

Lateral line complete; perforated scales 62-65, 63.5. Horizontal scale rows from dorsal-fin origin to lateral line 20. Horizontal scale rows from pelvic-fin origin to lateral line 12. Horizontal scale rows from anal-fin origin to lateral line15-17, 15.7. Predorsal scales 68-80, 74.5. Scale rows around caudal peduncle 20-21, 20.7. Scale row along anal-fin base, extending slightly beyond middle 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 11-14, 13.2. Maxillary teeth conical, 55-59, 65.2; larger specimens generally with higher counts. Dentary with one canine-like tooth followed by 4-5, 4.3 conical teeth, another canine-like tooth and posterior row of 32-37, 34.7 conical teeth. Gill-rakers on lower limb of first gill-arch 8-9, 8.6. 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 regions, with scattered chromatophores sometimes situated along miosepta of epaxial and hypaxial muscles forming V-shaped patterns. Irregularly shaped vertically elongate, dark blotch at humeral region encompassing about 3-4 scales horizontally and 6 to 7 vertically. Dorsal regions of head, snout and tip of lower jaw darker than remainder of head, dark coloration extending to median portion of lower jaw, fifth and sixth infraorbitals, between second and third infraorbitals as subocular blotch, and ventrally over anterior portions of preopercle and opercle. Triangular dark blotch present on caudal base, posterior chromatophores less intense and extending over basal portions of median caudal-fin rays. All fins hyaline with dark chromatophores situated mainly on interradial membranes. First and second unbranched rays of dorsal and first unbranched rays of pectoral and pelvic fins darker than remaining rays.

Distribution. This species is known from drainages of the rio Guaporé, Mato Grosso and of the rio Madeira, Amazonas, Brazil ( Fig. 7 ).

Specimens examined. Brazil, Amazonas: MZUSP 33423 , 1 , 65 mm SL, stream 15 km from Humaitá, rio Madeira drainage, approximately 7°30’S 63°01’W; Mato Grosso: MZUSP 28730 , 4 , 65-94 mm SL, tributary of rio Guaporé, 30 km above Vila Bela da Santíssima Trindade plus specimens listed in Lucena (1987) .

Figures

Fig. 15. Charax macrolepis, MZUSP 28730, female, 93.5 mm SL, Brazil,Amazonas, tributary of rio Guaporé, 30 km above Vila Bela da Santíssima Trindade.

Fig. 4. Orbital diameter as a function of head length for species of Charax.

Fig.7. Map of SouthAmerica showing the collecting sites of the Charax species, and the type locality of Charax delimai (purple circle). Charax apurensis - yellow square; C. caudimaculatus - white circle; C. condei - white square; C. gibbosus - purple triangle; C. hemigrammus - red star; C. leticiae - black circle;C. macrolepis-black triangle;C.metae-yellow triangle;C.michaeli - yellow circle;C.niger -blue triangle; C.notulatus - blue circle; C. pauciradiatus - red triangle; C. rupununi - red circle; C. stenopterus - green triangle; C. tectifer - green circle. Some symbols may represent more than one locality.