Charax, Scopoli, 1777

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 : 195-197

Key to species of Charax

1a. Lateral line incomplete, represented by anterior short segment; dorsal region of body anterior to dorsal fin origin lacking scales ........................................................................ 2

1b. Lateral line complete, perforated scales extending to base of caudal fin; dorsal region of body anterior to dorsal fin origin entirely covered with scales, except for small predorsal naked area ............................................................ 3

2a. Scale rows from pelvic-fin origin to lateral line 6-9 ......... 4

2b. Scale rows from pelvic-fin origin to lateral line 11-12 ............................................................. Charax hemigrammus

3a. Perforated scales on lateral line 42-44; 12 scale rows around caudal peduncle ...................................... Charax rupununi

3b. Perforated scales on lateral line 50-65; 15-22 scale rows around caudal peduncle ...................................................... 5

4a. Ectopterygoid teeth present; 30-41 teeth on posterior dentary row .................................................. Charax condei

4b. Ectopterygoid teeth absent; 18-28 teeth on posterior dentary row ......................................... Charax stenopterus

5a. Anal-fin origin along or slightly posterior to,vertical through origin of dorsal fin; ectopterygoid teeth always present ................................................................................... 6

5b. Anal-fin origin always anterior to vertical through origin of dorsal fin; ectopterygoid teeth absent (except in some specimens of Charax gibbosus ) ........................................ 8

6a. Superficial neuromasts absent on body; 9-10 gill rakers on lower branch of first gill arch ..................... Charax tectifer

6b. Superficial neuromasts present, especially visible on trunk scales ( Figs. 1 and 2 ); 7-9 (rarely 9) gill rakers on lower branch of first gill arch ......................................................... 7

7a. Total number of ectopterygoid teeth 20-50; humeral spot distance 41.6-47% of SL ( Fig. 3 ); 7-9 transverse scale rows between humeral spot and supracleithrum ......................................................................... Charax metae

7b. Total number of ectopterygoid teeth 3-15; humeral spot distance 48-51% of SL ( Fig. 3 ); 10-12 transverse scale rows between humeral spot and supracleithrum ...................................................................... Charax delimai

8a. Orbital diameter 25-28.5% of head length ( Fig. 4 ) ……… 9

8b. Orbital diameter 30.1-38.4% of head length ( Fig. 4 ) …… 10

9a. Snout length 20.3-22.8% of head length ( Fig. 5 ); 16-17 scale rows from dorsal-fin origin to lateral line; 9-13 scale rows from anal-fin origin to lateral line ....................................................... Charax caudimaculatus

9b. Snout length 24.3-26.3% of head length ( Fig. 5 ); 18-19 scale rows from dorsal-fin origin to lateral line; 14-17 scale rows from anal-fin origin to lateral line .................................................................... Charax notulatus

10a. Scale rows around caudal peduncle 20-22 .................... 11

10b. Scale rows around caudal peduncle 16-19 ................... 12

11a. Perforated scales on lateral line 54-62 ....................................................................... Charax apurensis

11b. Perforated scales on lateral line 63-65 .................................................................. Charax macrolepis

12a. Humeral spot distance 34.7-37.8% of standard length ( Fig. 3 ); 4-6 transverse scale rows between humeral spot and supracleithrum ............................................................. 13

12b. Humeral spot distance 38-44% of standard length ( Fig. 3 ); 8-10 transverse scale rows between humeral spot and supracleithrum ....................................................................... 14

13a. Scale rows from dorsal-fin origin to lateral line 18-20 ..................................................................... Charax michaeli

13b. Scale rows from dorsal-fin origin to lateral line 15-16 ... 15

14a. Scale rows from dorsal-fin origin to lateral line 3-14 ............................................................ Charax pauciradiatus

14b. Scale rows from dorsal-fin origin to lateral line 16-18 ....................................................................... Charax leticiae

15a. Predorsal scales 38-45; ectopterygoid teeth present in most specimens examined ....................... Charax gibbosus

15b. Predorsal scales; ectopterygoid teeth absent in all specimens examined 52-68 ............................. Charax niger

Figures

Fig. 1. Superficial neuromasts (black arrows) on lateral body scales of Charax delimai, male (a), MZUSP 81325, paratype, 102 mm SL, Brazil, Amazonas, igarapé Umari, tributary of rio Tiquié in community of São Pedro and female, (b), MZUSP 84988, paratype, 102 mm SL, Brazil, Amazonas, near old community of São Pedro.

Fig. 2. Superficial neuromasts (black arrow) on ventral body scales of Charax metae, CAS 69117, 59 mm SL.

Fig. 3. Humeral spot distance as a function of standard length for species of Charax.

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

Fig. 5. Snout length as a function of head length for Charax caudimaculatus and C. notulatus.