Characidium, Reinhardt, 1867

Agudelo-Zamora, Henry D., Ortega-Lara, Armando & Taphorn, Donald C., 2020, Characidium chancoense, a new species of South American darter from the Río Cauca drainage, Colombia (Characiformes: Crenuchidae), Zootaxa 4768 (2), pp. 249-263 : 260-261

Key to the Characidium species from the trans-Andean basins of Colombia

1a. Isthmus and chest lacking scales........................................... Characidium cf. boavistae ( Figs. 2k, l )

1b. Isthmus and chest scaled............................................................................... 2

2a. Sides of body with well-defined black spots located on, above and below a dark lateral stripe; dorsum crossed by 7–10 vertical bars that do not reach below lateral stripe......................................... C. phoxocephalum ( Figs. 2b, d )

2b. Sides of body without well-defined black spots; dorsum without vertical bars (in adult males of C. caucanum ) or with 6–18 vertical bars crossing dorsum (mean = 11), some of which reaching well below the horizontal lateral stripe... 3 ( Fig. 2a, c, e )

3a. Caudal-fin mark not forming a well-defined spot on peduncle, but dark pigment present on middle caudal-fin rays........................................................................................... 4 ( Figs. 2a, b, c, g, e, f )

3b. Caudal-fin mark present as well-defined spot on peduncle, dark pigment not extending onto middle caudal-fin rays.......................................................................................... 5 ( Figs. 2g, h, i, j, k, l )

4a. Vertical bars on body narrow (1/2–1 scale wide) and sinuous, not cuneate-shaped, usually 11 or more in juveniles and females, or sides of body without vertical bars in adult males............................ Characidium caucanum ( Fig. 2a, c, e )

4b. Vertical bars on body wide (up to four scales wide at widest dorsal end), anteriormost cuneate-shaped with vertex pointing down and reaching to, or just below, lateral line, posterior bars (1–4 counted from caudal-fin base) reaching well below the lateral line to ventral margin of caudal peduncle, usually fewer than 12 vertical bars present on sides of body (range 7–12)................................................................ Characidium chancoense , new species ( Fig. 2f )

5a. Sides of body with 9–10 wide vertical bars, none cuneate-shaped; body depth at origin of dorsal fin 19.9–25.8 % in SL, mean 25.5.................................................................. Characidium sanctjohanni ( Fig. 2h, j )

5b. Sides of the body with 6–16 thin vertical bars, all passing well below narrow horizontal stripe, none cuneate-shaped; body slender, body depth at origin of dorsal fin 17.8–27.4 % in SL, mean 23.4............... Characidium cf. zebra ( Fig. 2g, i )

Figures

FIGURE 2. Species of the genus Characidium present in the trans-Andean region of Colombia. a.) Characidium caucanum (holotype) FMNH 56057; b.) Characidium phoxocephalum (holotype), FMNH 56061; c.) C. caucanum, IUQ 563 (male); d.) C. phoxocephalum, IUQ 1250; e.) C. caucanum, IUQ 563 (female); f.) C. chancoense (holotype), IMCN 4528; g.) C. zebra (holotype), FMNH 53547; h.) C. sanctjohanni (holotype), ICN-MHN 211; i.) C. cf. zebra, SU 50391; j.). C. sanctjohanni, IMCN 8928; k.) C. cf. boavistae, UCO-P 409; l.) C. cf. boavistae, IMCN 2615.