Crenicichla zebrina, Montaña, Carmen G., López-Fernández, Hernán & Taphorn, Donald C., 2008

Montaña, Carmen G., López-Fernández, Hernán & Taphorn, Donald C., 2008, A new species of Crenicichla (Perciformes: Cichlidae) from the Ventuari River, Upper Orinoco River Basin, Amazonas State, Venezuela, Zootaxa 1856, pp. 33-40 : 34-37

Crenicichla zebrina n. sp.

( Figs. 1–3 )

Holotype: MCNG 45975, 189.0 mm SL; Venezuela: Amazonas, Orinoco River drainage, lower Ventuari River in front of Cucurital fishing camp, 04º07’03”, 66º40’47”, C.G. Montaña, 26 June 2002.

Paratype: ROM 82529 (ex MCNG 45803) 1 ex., 264.0 mm SL; Venezuela: Amazonas, Orinoco River drainage, lower Ventuari River, at 100 of the mouth of Caño Kanaripo, 04º04’58”, 66º50’54”, C.G. Montaña, 9 Mar 2002.

Diagnosis. Crenicichla zebrina is distinguished from all congeners by its pigmentation pattern, which includes the unique combination of a large, more or less oval-shaped humeral spot, and thin, dark vertical bars on the caudal half of the body which are separated by thinner yellowish vertical bars. It further differs from all other species in the C. acutirostris group except C. tigrina by a higher lateral scale count (E1=114 versus 111 or less). It can be distinguished from C. tigrina , by the presence of a large, non-ocellated humeral spot (versus no spot), lower dorsal spine counts (XXII versus XXIII–XXIV), and the presence of alternating light and dark colored bars restricted to approximately the caudal half of the body (vs. bars on all the body in C. tigrina ).

Description. Crenicichla zebrina ( Fig. 1 ) is described from two specimens collected in the lower Ventuari River, a tributary of the Orinoco River, Amazonas State, Venezuela. All measurements based on the holotype (189.0 mm SL) and the paratype (264.0 mm SL). Measurements are given in Table 1 .

Shape. Body elongate, body depth 17.8–19.3% SL. Head deeper than wide. Caudal peduncle length 1.2 to 1.5 times in depth. Snout long, rounded in dorsal view, pointed in lateral view. Lower jaw slightly prognathous, its articulation anterior to the margin of orbit, ascending premaxillary process reaching vertical line through middle of orbit. Maxilla reaching to vertical line through anterior margin of orbit. Lips moderately wide, lower lip folds separated anteriorly at symphsis; folds of upper lip not continuous but interrupted at the wide symphyseal region; postlabial skin fold margin slightly concave. Orbit supralateral, rising slightly above frontal contour, not visible from ventral view, chiefly in the anterior half of the head. Nostrils dorsolaterally placed, approximately on anterior third of distance between orbit and margin of postlabial skin fold, with low tubular margin but no anterior marginal skin flap. Preopercle without serrations.

Scales. E1 114 (2), scales between upper lateral line and dorsal-fin base 17–18 anteriorly, 9–11 posteriorly; 6 scale rows between lateral lines. Scales on upper lateral line 25–26 and lower lateral line 14–15. Anterior upper lateral-line scales slightly larger and more elongate than adjacent scales. Flank scales ctenoid. Cycloid scales on head, anteriorly on back, along dorsal fin base, chest, and on belly below line from lower edge of pectoral fin base to anal fin origin and near fin base. Predorsal and prepelvic scales small, superficially embedded in skin. Cheek fully scaled; 6 scale rows below eye embedded in skin. Interopercle naked. Circumpeducular scale rows 22 above lateral line, 22 below.

Fin scales. Scales absent on dorsal, anal, pectoral, and pelvic fins. Caudal fin squamation extending to the middle of fin.

Fins. Dorsal XXII-15 (1), XXII-16 (1); anal III-11 (2). First dorsal spine about 1/4–1/5 length of last; spines increasing in length to the last, subequal from about 10th. Soft part of dorsal fin pointed, 7th–8th rays reaching slightly beyond base of caudal fin. Caudal fin rounded. Soft anal fin with acuminate tip, not reaching base of caudal fin. Pectoral fin rounded, reaching halfway to anal-fin origin. Pelvic fin inserted well posterior to vertical through pectoral-fin insertion, with acuminate tip, second ray longest, reaching about halfway to anal-fin origin or slightly beyond.

Teeth. All teeth pointed, erect or slightly recurved. Teeth of outer row (25 in right hemiseries in holotype) distinctly larger than teeth of inner rows and larger anteriorly than posteriorly. Upper jaw with 5–6 inner rows of conic, slightly recurved teeth; an open space present between right and left hemiseries at symphysis; outer teeth movable, inner teeth depressible. Lower jaw with 4–5 rows of conic teeth, anterior row slightly larger, separated from inner rows by twice as much space as between inner rows, gap at symphysis, 20 in right anterior hemiseries (holotype), all teeth depressible; of variable size.

Gills. External rakers on first gill arch, 9 (1).

Tooth plates. Lower pharyngeal toothplate wide; length of bone 65% of width; dentigerous area 67% of width, 50% of length; 22 teeth in posterior row, 7–8 on median row. Anterior teeth subconical or subcylindrical, slightly laterally compressed and slightly wider at the base, recurved, conic; teeth on antero-lateral margin progressively wider at the base towards caudal edge of plate; postero-median teeth larger, cylindrical with blunt cusps, conic ( Fig. 2 ).

Vertebrae. 23+18 = 41 (holotype only).

Coloration in alcohol. Sides of head, cheek and body brown; snout and upper and lower lips gray. Brown, inverted triangle-shaped blotch below orbit, reaching about half the depth of cheek. Ventrum brown to yellow with pale vertical bars. Dark brown vertical bars on sides from middle of body to caudal fin ( Fig. 1 ); bars reach about ¾ of the vertical distance between the dorsal base and the anal base. Pectoral and pelvic fins pale yellow. Dorsal, anal, and caudal fins pale yellow with brown vertical bars and a brown border. Soft anal fin with dark pointed tips. Dark brown to black oval-shaped humeral spot just posterior to the pectoral fin, bisected at about 1/3 of height by upper lateral line. Ocellated black caudal spot located on second lateral bar posterior to the base of caudal fin.

Live colors. Live colors are described from personal observation in the field (CGM) and two photographs of live specimens taken in the field. Background color is dark brown with dark brown or gray vertical bars separated by narrower yellowish to olive bars. There are five thicker vertical bars on the sides, starting behind opercle and extending to caudal end of dorsal fin base. On caudal third of body bars are narrower, closer together and extend onto caudal fin. Between the narrow bars there are fine vertical, yellow to olive green bars. Head and lips are dark gray. Small black spot below orbit. Dorsal, anal and caudal fin with brown vertical bars as on body. Pectoral and pelvic fin without bars, uniformly yellow to olivaceous. Humeral spot black, ocellated with yellow ring.

Distribution and habitat ( Fig. 3 ). Crenicichla zebrina is known only from the Ventuari River, the largest Venezuelan tributary of the upper Orinoco River basin. The only two known specimens were collected in rocky habitat about 1 m deep, in clear water with bedrock substrate.

Etymology. From the common name zebra for the striped African equid and the Latin feminine suffix – ina, referring to the zebra-like pattern of vertical dark bars in the caudal region of the body. To be regarded as an adjective in feminine form.

Figures

FIGURE 1. Crenicichla zebrina. Holotype MCNG 45975, 189.0 mm SL; Venezuela: Amazonas, Orinoco River drainage, lower Ventuari River in front of Cucurital fishing camp.

FIGURE 2. Crenicichla zebrina. Paratype. Lower pharyngeal tooth plate in occlusal view. ROM 82529, 264.0 mm SL. Scale bar = 5 mm.

FIGURE 3. Distribution map of Crenicichla zebrina n. sp. lower Ventuari River, Amazonas State, Venezuela.

Tables

TABLE 1. Morphometrics of Crenicichla zebrina.

Measurements	Holotype MCNG-45975	Paratype ROM-82529
SL mm	189.0	264.0
Body depth	33.8	51.0
Head length	54.0	83.7
Caudal-peduncle length	28.9	35.7
Caudal-peduncle depth	19.5	28.8
Pectoral-fin length	30.4	42.5
Pelvic-fin length	27.0	42.5
Last dorsal-fin spine length	15.9	27.0
Snout length	19.6	28.4
Head width	21.7	30.4
Orbital diameter	10.0	12.9
Interorbital width	10.0	17.0
Preorbital depth	5.5	9.3
Upper jaw length	18.3	29.5
Lower jaw length	26.1	40.7