Cyphocharax notatus (Steindachner 1908)

Cyphocharax notatus (Steindachner)

Curimatus notatus Steindachner, 1908:166 [type locality: Brazil: Pará (= Belém) fish market].—Eigenmann, 1910:421 [reference].—Fernández-Yépez, 1948:73 [reference].—Vari, 1989a, tables 2, 3 [assignment to Cyphocharax].

Curimatus hermanni Ahl, 1931:207 [type locality: Brazil: Pará, Rio Capim].—Vari, 1989a, tables 2, 3 [assignment to Cyphocharax]. [New synonymy.]

Curimatus hasemani.—Femández-Yépez, 1948:73 [? erroneous citation of C. hermanni Ahl].

Curimata notata.—Fowler, 1950:288 [literature compilation]; 1975:369 [reference].

Curimata hermanni.—Fowler, 1975:369 [reference].

DIAGNOSIS.—Cyphocharax notatus is the only member of the genus with a discrete patch of dark pigmentation on the distal portions of the last unbranched and anterior branched rays of the dorsal fin. The only other species of Cyphocharax with a distinct patch of dark pigmentation on the dorsal fin is C. vexillapinnus in which the middle rather than distal portions of the fin are pigmented. The two species also differ in the degree of development of pores along the lateral-line scale series (pores developed along entire series in notatus versus only on anterior 5 to 8 scales in vexillapinnus), relative body depth (0.31–0.37 of SL versus 0.38–0.47 respectively), and relative depth of caudal peduncle (0.11–0.13 of SL versus 0.14–0.16).

DESCRIPTION.—Body relatively elongate, somewhat compressed laterally. Dorsal profile of head convex from tip of snout to vertical line running between nostrils, straight or very slightly concave from that line to tip of supraoccipital spine. Dorsal profile of body smoothly curved from tip of supraoccipital spine to origin of dorsal fin, curvature more pronounced in larger specimens; straight and posteroventrally slanted at base of dorsal fin, gently convex from base of last dorsal-fin ray to caudal peduncle. Dorsal surface of body with distinct, although obtuse, 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 obtusely flattened, with median series of scales that are not noticeably enlarged relative to those on ventrolateral portion of body. Median scale series flanked on each side by series of similar-sized scales flexed medially to conform to shape of obtuse lateral angles along that portion of body. Obtuse median keel present posterior to pelvic-fin origin. Secondary obtuse keel on each side of postpelvic portion of body one scale dorsal of ventral midline.

Greatest body depth at origin of dorsal fin, typically relatively deeper in larger specimens, depth 0.31–0.37 [0.32]; snout tip to origin of dorsal fin 0.46–0.52 [0.47]; snout tip to origin of anal fin 0.82–0.87 [0.86]; snout tip to origin of pelvic fin 0.52–0.57 [0.54]; snout tip to anus 0.76–0.81 [0.80]; origin of dorsal fin to hypural joint 0.55–0.60 [0.56]. Dorsal fin obtusely pointed in profile distally; more rounded distally in larger specimens; last unbranched and first branched rays approximately 2.5–3.0 times length of ultimate ray. Pectoral fin pointed in profile distally; length of pectoral fin 0.18–0.22 [0.19], extends slightly over one-half distance to vertical line through origin of pelvic. Pelvic fin pointed in profile distally, length of pelvic fin 0.21–0.25 [0.23], reaches slightly less than two-thirds distance to origin of anal fin in smaller specimens, slightly less than one-half that distance 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 0.11–0.13 [0.11].

Head profile obtusely pointed anteriorly in profile; head length 0.25–0.30 [0.27]; upper jaw slightly longer than lower, mouth barely subterminal; snout length 0.27–0.33 [0.31]; nostrils of each side very close, anterior circular, posterior crescent-shaped with aperture closed by thin flap of skin separating nares; orbital diameter 0.29–0.35 [0.34]; adipose eyelid present in specimens of all sizes, with vertically ovoid opening over center of eye, eyelid most developed anteriorly, overall degree of development of eyelid greater in larger specimens; length of postorbital portion of head 0.37–0.43 [0.38]; gape width 0.23–0.28 [0.23]; interorbital width 0.39–0.45 [0.40].

Pored lateral-line scales from supracleithrum to hypural joint 30 to 35 [32]; all scales of lateral line pored, canals in lateral-line scales straight; 2 to 4 series of pored scales extend beyond hypural joint onto caudal-fin base; 5 to 6 (5 in most specimens, 5 and 6 rare) [5] scales in transverse series from origin of dorsal fin to lateral line; 4 to 5 [4] scales in transverse series from lateral line to origin of anal fin. Small patch of scales extending onto central portion of each lobe of caudal fin; scales slightly smaller than those on proximate portion of caudal peduncle. Scale patches limited to basal one-quarter of associated fin rays in smaller individuals, extending about one third distance along center of each lobe in largest specimens examined.

Dorsal-fin rays ii,9 [ii,9]; anal-fin rays ii,7 [ii,7]; pectoral-fin rays 14 to 15 [14]; pelvic-fin rays i,8 or 9 (9 rare) [i,8].

Total vertebrae 32 (7), 33 (7).

COLOR IN LIFE.—Géry (1977:237) included a life photo of an unidentified curimatid that is apparently Cyphocharax notatus. The head and body are bright silver, somewhat darker dorsally. The distal one-third of the anterior half of the dorsal fin and the tips of the lobes of the caudal fin are black.

COLOR IN ALCOHOL.—Overall coloration of specimens retaining guanine on scales silvery, darker on dorsal surface of head and somewhat darker on dorsal portions of body. Ground coloration of specimens lacking guanine on scales tan to light brown, larger specimens darker overall. Deep-lying dusky band extends along midlateral surface of body. Band extends from supracleithrum to region of hypural joint in specimens up to 60 mm SL, extends anteriorly only to under dorsal fin in specimens greater than 80 mm SL.

Last unbranched dorsal-fin ray and first five branched dorsal-fin rays with distinct black spot on distal portions of rays and associated membranes (Figures 23, 24). Spot most intense and most developed anteriorly; pigmentation more diffuse and covering relatively smaller portions of distal sections of fourth and fifth branched fin rays. Remainder of dorsal-fin membranes hyaline in specimens under 50 mm SL but with fin rays outlined by series of small chromatophores in larger individuals. Distal portions of caudal-fin lobes with faint dusky pigmentation in smaller specimens retaining complete fins; pigmentation on that portion of fin more intense in larger individuals, forming distinct black patches (Figure 24). Remainder of caudal fin hyaline in smaller individuals, dusky with fin ray segments outlined by series of very small chromatophores in larger specimens. Anal fin hyaline in specimens up to 80 mm SL, dusky with scattered dark chromatophores on membranes in larger specimens. Occasional larger specimens with distinct spot of dark pigmentation on distal portions of middle rays of anal fin. Paired fins hyaline in most examined specimens, but relatively dusky in some population samples from the Rio Guaporé basin in Brazil (MZUSP 37440).

AUTAPOMORPHIES OF Cyphocharax notatus.—Two features of the pigmentation of Cyphocharax notatus are unique to the species in the Curimatidae. In C. notatus the distal portions of the anterior rays of the dorsal fin are black (Figures 23, 24), whereas in other curimatids that portion of the fin is hyaline, or at most slightly dusky. The pigmentation in C. notatus is thus considered autapomorphic for the species. Mid- to large-sized individuals of the species also have blackened distal portions of the lobes of the caudal fin (Figure 24), another feature not found elsewhere in the family, and thus hypothesized autapomorphic for C. notatus.

DISTRIBUTION.—Rio Tocantins, Rio Amazonas, and Rio Capim basins (Figure 25).

MATERIAL EXAMINED.—294 specimens (70, 44.1–123.0).

BRAZIL. Pará: “Area surrounding Pará, Pará [= Belém] fish market,” NMW 75793, 1 (75.3, holotype of Curimatus notatus). Rio Tocantins, vicinity of Cametá, Igarapé Maloca, MZUSP 21255, 2. Lago along margin of Igarapé Espírito Santo, between Baião and Tucuruí, along Rio Tocantins, MZUSP 21278, 1. Rio Tocantins, Lago Trocará, below Tucuruí, MZUSP 21339, 7 (70.5–102.0). Rio Capim, Lago Jurunundéua, MZUSP 21221, 9 (50.1–59.0). Rio Tocantins, Laguinho near Tucuruí, MZUSP 21238, 102. Amazonas: Rio Negro, Paraná do Jacaré, USNM 311134, 4 (44.1–50.3). Rio Madeira basin, Rio Livramento, MCZ 34130, 3 (2, 109.5–111.5); AMNH 12709, 2 (95.6–110.0), AMNH uncat., 3 (93.9–106.5); AMNH uncat., 2 (97.3–110.3); AMNH uncat., 2 (96.7–109.7); AMNH uncat., 2 (109.0–115.3); AMNH uncat., 3 (98.5–102.5); AMNH uncat., 2 (94.5–111.2). Rio Urubu, 25 mi [= 45 km] from Itacoatiara, USNM 179550, 2 (67.0–76.8; 1 specimen cleared and counterstained for cartilage and bone). Mato Grosso: Rio Tapaiós system, upper Rio Juruena, USNM 194342, 1 (74.8). Rio Guaporé, vicinity of Vila Bela da Santíssima Trindade, MZUSP 37440, 106 (5, 60.8–82.7); USNM 313403, 10 (76.5–97.5); MZUSP 37516, 16. Rio Alegre, tributary to Rio Guaporé, 30 km from Vila Bela da Santíssima Trindade, MZUSP 37472, 1.

PERU. Loreto: Río Ucayali system, isolated pool at left bank of Quebrada Carahuayte at km 20 on road from Jenaro Herrera to Colonia Angamos, NRM 23731, 1 (59.5). Río Itaya, AMNH uncat., 1 (44.1). Río Ucayali system, Quebrada Copal, at km 15 on road from Jenaro Herrera to Colonia Angamos, NRM 23737, 1 (82.7). Madre de Dios: Río Tambopata system, Quebrada San Roque at km 11 on Puerto Maldonado to Cuzco road, NRM 23739, 2 (108.8–118.3).

ECUADOR. Napo: Jatuncocha, BMNH 1970.4.3:54, 1 (86.0).

BOLIVIA. Beni: Río Itenez, 9 km SE of Costa Marques, Brazil, AMNH 37717, 4 (56.0–61.8). Arroyo Grande, 4 km W of Guayaramerín, at Riberalta road, AMNH 37712, 3 (111.5–123.0).