Cyphocharax nagelii (Steindachner 1881)

Cyphocharax nagelii (Steindachner)

Curimatus Nagelii Steindachner, 1881:98 [type locality: “vicinity of Rio [de] Janeiro “” ]; 1882:11 [ “vicinity of Rio [de] Janeiro,” based on Steindachner, 1881 publication].—Vari, 1989a, tables 2, 3 [assignment to Cyphocharax].

Curimatus nagelii.—Eigenmann and Eigenmann, 1889:425 [citation]; 1891:47 [reference].—Eigenmann, 1910:421 [reference].

Curimatus elegans.—Amaral Campos, 1945:460 [Brazil: Säo Paulo, Rio Mogi-Guaçu].

Curimatus plumbeus? Amaral Campos, 1945:461 [Brazil: Säo Paulo, Rio Mogi-Guaçu; not C. plumbeus, probably C. nagelii].

Bondia nageli.—Femández-Yépez, 1948:67 [assignment to Bondia].

Curimata nagelii.—Fowler, 1950:288 [literature compilation].

Curimata plumbea.—Gomes and Monteiro, 1955:89 [Brazil: Säo Paulo, Pirassununga].

Curimatus cf. platanus.—Foresti et al., 1974:249 [Brazil: Säo Paulo, Rio Mogi-Guaçu; karyotype].—Oliveira et al., 1988:594 [Brazil: Säo Paulo, Botucatu; karyotype].

Pseudocurimata plumbea.—de Godoy, 1975:594, fig. 133 [Brazil: Rio Mogi Guassu (= Mogi-Guaçu); life history].

DIAGNOSIS.—The 39 to 45 scales in the lateral line to the hypural joint discriminate Cyphocharax nagelii from C. abramoides, C. stilbolepis, and C. platanus, that have 48 or more scales in that series, and from all other species of Cyphocharax, with the exception of C. leucostictus, that have 38 or fewer lateral-line scales. The dark, midlateral stripe on the caudal peduncle of C. nagelii distinguishes it from C. leucostictus that lacks that pigmentation pattern. The two species also differ in the relative length of the pelvic fin (0.17–0.20 of SL in nagelii versus 0.21–0.25 in leucostictus), relative orbital diameter (0.25–0.30 versus 0.30–0.36), number of vertebrae (34 versus 31 to 33), and less discretely in the number of scales in a transverse series from the lateral line to the origin of the dorsal fin (7 to 9 versus 6 to 7).

DESCRIPTION.—Body elongate, laterally compressed, more so in larger specimens. Dorsal profile of head somewhat rounded from upper jaw to vertical line through posterior nostril, straight or very slightly convex from that line to tip of supraoccipital spine. Dorsal profile of body smoothly curved from tip of supraoccipital spine to origin of dorsal fin; straight and slightly posteroventrally slanted at base of dorsal fin, straight or very gently convex from base of last dorsal-fin ray to caudal peduncle. Dorsal surface of body with indistinct median keel anterior to dorsal fin, smoothly rounded transversely posterior to fin. Ventral profile of body gently curved from tip of lower jaw to caudal peduncle. Prepelvic region very obtusely flattened, scales not enlarged relative to those on adjoining portions of body. Obtuse median keel posterior to pelvic fin insertion.

Greatest body depth at origin of dorsal fin, depth 0.29–0.33 [0.33]; snout tip to origin of dorsal fin 0.46–0.50 [0.47]; snout tip to origin of anal fin 0.80–0.84 [0.82]; snout tip to insertion of pelvic fin 0.52–0.56 [0.55]; snout tip to anus 0.75–0.79 [0.77]; origin of dorsal fin to hypural joint 0.55–0.60 [0.56]. Dorsal fin obtusely pointed in profile distally; last unbranched and first branched rays approximately three times length of ultimate ray. Pectoral fin pointed in profile distally; length of pectoral fin 0.15–0.18 [0.18], extends about one-half to two-thirds distance to vertical line through insertion of pelvic fin, relatively shorter in larger specimens. Pelvic fin pointed in profile distally; length of pelvic fin 0.17–0.20 [0.18], reaches about one-half to two-thirds distance to origin of anal fin. Caudal fin forked. Adipose fin well developed. Anal fin emarginate, anteriormost branched rays twice length of ultimate ray. Least depth of caudal peduncle 0.12–0.13 [0.12].

Head distinctly pointed in profile overall, snout somewhat rounded, head length 0.27–0.30 [0.28]; upper jaw longer than lower, mouth subterminal; snout length 0.29–0.32 [0.29]; nostrils of each side very close, anterior circular, posterior crescent-shaped with aperture closed by thin flap of skin separating nares; orbital diameter 0.25–0.30 [0.29]; adipose eyelid present, with vertically ovoid opening over center of eye; length of postorbital portion of head 0.43–0.46 [0.45]; gape width 0.22–0.25 [0.22]; interorbital width 0.36–0.39 [0.37].

Pored lateral-line scales from supracleithrum to hypural joint 39 to 45 [41]; all scales of lateral line pored, canals in lateral-line scales straight; 4 to 6 series of pored scales extend beyond hypural joint onto caudal-fin base; 7 to 9[8] scales in transverse series from origin of dorsal fin to lateral line; 6 to 7 [7] scales in transverse series from lateral line to origin of anal fin.

Dorsal-fin rays ii,9 or 10, or iii,9 [ii,9] (when three unbranched rays present, first very short); anal-fin rays ii,7 or 8 or iii,7 [ii,7] (when three unbranched rays present, first very short); pectoral-fin rays 13 to 15 [14]; pelvic-fin rays i,8 or 9 [i,8].

Total vertebrae 34 (18).

COLOR IN ALCOHOL.—Overall coloration of specimens retaining guanine on scales golden or silvery-golden, darker on dorsal portions of head and body. Ground coloration of specimens lacking guanine on scales tan. No pronounced pigmentation pattern on head or body. Horizontally elongate patch of dark chromatophores extends along midlateral surface of caudal peduncle and onto anterior portions of bases of middle rays of caudal fin; pigmentation most pronounced posteriorly. Chromatophore patch extending eight to ten scales horizontally and two scales vertically. Caudal-fin rays outlined by series of small, dark chromatophores; pattern most pronounced on middle rays. Other fins hyaline.

DISTRIBUTION.—Upper Rio Paraná system above Sete Quedas Falls (Figure 7).

ECOLOGY.—de Godoy (1975:596–597) noted that Cyphocharax nagelii (identified in his paper as Pseudocurimata plumbea) engaged in large-scale seasonal migrations in the Rio Mogi Guassu (= Mogi-Guaçu), a tributary of the upper Rio Paraná. Juveniles up to 40 to 50 days in age were reported to be zooplanctivores and larger individuals were detritivores.

KARYOTYPE.—According to Foresti et al. (1974:249) followed by Oliveira et al. (1988:594) this species (listed by those authors as Curimatus cf. platanus) has a 2n = 54 chromosome count with a fundamental number of 108. There was no evidence of chromosomal heteromorphism in the species.

DISTRIBUTION.—Rio Amazonas basin and coastal drainages of Amapá, Brazil (Figure 11).

GEOGRAPHIC VARIATION.—Population samples of Cyphocharax leucostictus from the coastal drainages of Amapá, Brazil, in the eastern portion of the species range agree with those from the Amazon basin in nearly all examined features. The two populations differ, however, in relative body depth (0.34–0.38 of SL in Amapá samples versus 0.31–0.35 in those from Amazon) and lateral-line scale counts (39 to 41 versus 40 to 45 respectively). Additional material from Amapá and adjoining regions is necessary to determine whether these difference should be recognized taxonomically.

MATERIAL EXAMINED.—196 specimens (49, 45.4–104.8 mm).

BRAZIL. Amapá: Rio Matuanun, Macapá, MNRJ 11211, 10 (5, 95.7–104.8). Braço do Rio Macacoari, MNRJ 11205, 1 (100.5). Pará: Rio Tapajós, Alter do Chão, USNM 267983, 2 (102.2–104.2). Rio Tapajós, Itaituba, USNM 267978, 6 (1 specimen cleared and counterstained for cartilage and bone); USNM 267980, 2. Rio Xingu, NMW 68817, 1 (78.4, holotype of Curimatus (Curimatella) xinguensis). Rio Xingu, Belo Monte, USNM 267982, 2. Amazonas: Rio Negro, MCZ 787, 1 (103.5, lectotype of Curimatus leucostictus). Rio Negro, vicinity of Manaus, MZUSP 6688, 33 (4, 70.6–99.5). Lago Alexo (= Lago do Aleixo), MCZ 20315, 1 (70.0, paralectotype of Curimatus leucostictus). Paraná de Janauacá, Lago do Castanho, USNM 229172, 4 (55.3–85.3). Rio Jauaperi, between mouth and 100 km up river, MZUSP 21156, 5 (63.1–94.0). Rio Jauaperi, near mouth, USNM 243231, 1 (73.2). West of Moura, near junction of Rio Negro and Rio Branco, ANSP 139329, 1 (89.3). Lago José Açu, MZUSP 7632, 2 (80.5–88.2). Rio Negro, Anavilhanas, beach on Lago da Prata, USNM 268020, 34 (14, 45.4–78.2). Cabeceira do Lago Beruri, Igarapé Chefe, MZUSP 6426, 2. Roraima: Rio Branco, Cachoeira do Bem Querer, USNM 268022, 1 (78.0). Rio Branco, Beach at Marará, near mouth of Rio Branco, USNM 268023, 50. Mato Grosso: Rio Araguaia, Santa Terezina, MZUSP 20838, 2. Rondônia: Lago do Cururu, USNM 267984, 11 (4, 71.7–97.4). Rio Madeira, beach at Calama, USNM 267979, 1 (76.1).

VENEZUELA. Territorio Federal Amazonas: Río Negro, rapids below the mouth of the Río Casiquiare, approx. 10 km north of San Carlos de Río Negro, MBUCV V-11364, 1 (57.0). Caño Darigua, tributary of Río Negro entering Río Negro on the left bank approx. 17 km S of San Carlos de Río Negro, MBUCV V-11238, 10. Headwaters of the Río Atabapo, MBUCV V-7176, 5; MBUCV V-7175, 7.

Cyphocharax pantostictos Vari and Barriga

Cyphocharax pantostictos Vari and Barriga, 1990:551, figs. 1–4 [type-locality: Ecuador: Napo, Laguna de Jatuncocha; distribution in Ríos Napo, Putomayo, Ucayali, and Nanay systems in eastern Ecuador and northern Peru].—Vari and Howe, 1991:19 [listing of type-specimens in NMNH].—Ortega, 1991:2 [occurrence in Peru].

DIAGNOSIS.—The striking pattern of seven to nine horizontal series of prominent dark spots situated over the center of the scales on the lateral and dorsolateral surfaces of the body is unique to Cyphocharax pantostictos in the genus. Only two other Cyphocharax species, C. multilineatus of the Río Negro system in Venezuela and Brazil, and C. helleri distributed through Guyana, Surinam, French Guiana, and the northern portion of the state of Amapá, Brazil, have patterns of horizontal dark body pigmentation somewhat reminiscent of that in C. pantostictos. The patterns of dark body pigmentation in C. multilineatus and C. helleri differ from that in C. pantostictos in forming multiple, solid, wavy, horizontal lines rather than horizontal series of discrete rotund spots (compare Figures 12, 13–17, 19). Furthermore, the dark stripes in C. multilineatus and C. helleri are positioned along the regions of overlap of horizontal rows of scales along the body, rather than being aligned along the center of the scale rows as are the spots in C. pantostictos (Figure 12). Cyphocharax multilineatus also has a discrete dark band across the midlateral surface of the head anterior and posterior to the orbit, a pigmentation pattern lacking in C. pantostictos. Cyphocharax pantostictos, in turn, is characterized by a well-developed, midlateral, horizontally elongate patch of dark pigmentation on the caudal peduncle that is absent in C. multilineatus. The two species also differ in the relative length of the postorbital portion of the head (0.42–0.46 of HL in pantostictos versus 0.35–0.40 in multilineatus), relative gape width (0.24–0.28 of HL versus 0.18–0.23), and to a lesser degree in relative orbital diameter (0.27–0.32 of HL versus 0.31–0.37). Finally, Cyphocharax pantostictos lacks the large, rotund spot of dark pigmentation that occurs on the midlateral surface of the caudal peduncle in C. helleri.

DESCRIPTION.—Body moderately elongate, somewhat compressed laterally. Dorsal profile of head convex from upper lip to vertical line through posterior nostril, straight from that line to tip of supraoccipital spine. Dorsal profile of body smoothly convex from posterior portion of head to origin of dorsal fin; straight or slightly convex, posteroventrally slanted at base of dorsal fin, gently convex from base of last dorsal-fin ray to caudal peduncle. Dorsal surface of body with indistinct median keel anterior to dorsal fin, smoothly rounded transversely posterior to fin. Ventral profile of body gently curved from tip of lower jaw to caudal peduncle. Prepelvic region very obtusely flattened, scales of that area not notably enlarged relative to those on ventrolateral surfaces of body. Median prepelvic scale series somewhat irregular, particularly proximate to origin of pelvic fin. No distinct median keel posterior to origin of pelvic fin. Barely discernable secondary obtuse keel on each side of postpelvic portion of body about two scales dorsal of ventral midline.

Greatest body depth at origin of dorsal fin, depth 0.35–0.40 [0.37], relatively deeper in larger specimens; snout tip to origin of dorsal fin 0.47–0.52 [0.50]; snout tip to origin of anal fin 0.83–0.85 [0.83]; snout tip to origin of pelvic fin 0.52–0.57 [0.56]; snout tip to anus 0.78–0.79 [0.78]; origin of dorsal fin to hypural joint 0.54–0.58 [0.56]. Dorsal fin obtusely pointed in profile distally; last unbranched and first branched rays approximately two to two and one-half times length of ultimate ray. Pectoral fin obtusely pointed in profile distally; length of pectoral fin 0.18–0.21 [0.20], extending slightly over one-half distance to vertical line through origin of pelvic fin. Pelvic fin pointed overall in profile distally, length of pelvic fin 0.20–0.23 [0.22], tip of fin reaches to anus in holotype, falls somewhat short of that point in larger specimens. Caudal fin forked. Adipose fin well developed. Anal fin emarginate, anteriormost branched rays about two and one-half times length of ultimate ray. Least depth of caudal peduncle 0.12–0.14 [0.14].

Head profile pointed anteriorly overall, head length 0.29–0.33 [0.31]; upper jaw somewhat longer than lower, mouth subterminal; snout length 0.27–0.31 [0.30]; nares of each side very close, anterior rotund, posterior crescent-shaped with aperture partially closed by thin flap of skin separating nares; orbital diameter 0.27–0.32 [0.31]; adipose eyelid present, moderately developed, with rotund opening over center of eye; length of postorbital portion of head 0.42–0.46 [0.44]; gape width 0.24–0.28 [0.27]; interorbital width 0.39–0.43 [0.43].

Pored lateral-line scales from supracleithrum to hypural joint 29 to 31 [29]; all scales of lateral line pored, canals in scales straight; 2 or 3 series of pored scales extend beyond hypural joint onto caudal-fin base; 4 [4] scales in transverse series from origin of dorsal fin to lateral line; 3 to 4 [4] scales in transverse series from lateral line to origin of anal fin.

Dorsal-fin rays ii,9 [ii,9]; anal-fin rays ii,7 or iii,7 (when three unbranched rays present, first very short) [ii,7]; pectoral-fin rays 13 to 15 [15]; pelvic-fin rays i,8 or i,7,i [i,7,i].

Total vertebrae 31 (10).

COLOR IN LIFE.—(Based on photograph of a paratype (USNM 280573) from the Río Nanay of Peru taken shortly after capture.) Overall coloration silvery with slightly olive-grey cast on dorsal portions of head and body. Series of black spots arranged in horizontal series along dorsal and lateral surfaces of body. Distinct black midlateral stripe on caudal peduncle. Fins hyaline.

COLOR IN ALCOHOL.—Available specimens largely lacking guanine on scales. Overall ground coloration yellowish-tan, darker on dorsal portions of head and body. Scales on lateral and dorsal surfaces of body with dark patch of pigmentation on each scale; size of spots largest midlaterally; overall intensity of spots not as pronounced in smaller individuals. Spots arranged in seven to nine horizontal series, dorsal and ventral series of dark spots not apparent in smaller specimens. Series of dark spots on scales less developed posteriorly on scale rows ventral of lateral line; very poorly developed in series starting immediately posterodorsal to origin of pectoral fin. Intense dark spots also progressively less pronounced in horizontal series dorsal to lateral line. Patches of dark pigmentation located on center of scale, with midpoint of spots lying medial of margin of preceding scale. Scales dorsal to lateral line with secondary area of diffuse dark pigmentation posterior to discrete central dark spot; secondary dark pigmentation increasingly pronounced on dorsal portions of body, but merging into overall darker pigmentation of body along dorsal scale series. Dark pigmentation patches on scales along lateral line merging posteriorly into distinct horizontal stripe on midlateral surface of caudal peduncle; stripe continuing onto base of middle caudal-fin rays. Deeper lying, dusky band extends along midlateral surface of body from supracleithrum to caudal peduncle.

Caudal fin with short horizontal streak of dark pigmentation on basal portions of middle rays; basal two-thirds of fin somewhat more dusky than remainder of fin. Median and paired fins somewhat dusky.

DISTRIBUTION.—Río Napo, Río Putumayo, Río Ucayali, and Río Nanay systems in eastern Ecuador and northeastern Peru (Figure 11).

AUTAPOMORPHIES OF Cyphocharax pantostictos.—The pattern of multiple series of dark spots over the center of the scales on the lateral and dorsolateral surfaces of the body in Cyphocharax pantostictos (Figure 12) is unique in the genus, but paralleled to a degree by the pigmentation pattern of Steindachnerina fasciata (Vari and Géry) (compare Figure 12 and fig. 39 in Vari, 1991). Within the context of the overall most parsimonious hypothesis of relationships within Steindachnerina (Vari, 1991) the pigmentation patterns of S. fasciata and Cyphocharax pantostictos are considered homoplastic. Thus the pigmentation pattern of C. pantostictos is considered autapomorphic for the species.

ECOLOGY.—Two specimens from Peru (USNM 280573; NRM 26567, formerly NRM SOK/1986293.5292) were collected in acidic blackwaters among grass and submerged vegetation. The specimens from the type-locality were collected in submerged vegetation in blackwaters of pH 5.5 at a depth of 1.5 m. The Río Yasuni specimens came from a slow flowing turbid stream with a pH of 6.0 and lacking submerged vegetation.

Cyphocharax nagelii és una espècie de peix de la família dels curimàtids i de l'ordre dels caraciformes.

Cyphocharax nagelii es una especie de peces de la familia Curimatidae en el orden de los Characiformes.

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Cyphocharax nagelii Cyphocharax generoko animalia da. Arrainen barruko Curimatidae familian sailkatzen da.

內氏駝背脂鯉，為輻鰭魚綱脂鯉目脂鯉亞目無齒脂鯉科的其中一個種，分布於南美洲巴拉那河上游流域，體長可達16.3公分，棲息在河川底中層水域，會進行季節性洄游，以有機碎屑等為食，生活習性不明。