Semaprochilodus brama (Valenciennes 1850)

Potamodromous. Migrating within streams, migratory in rivers, e.g. Saliminus, Moxostoma, Labeo. Migrations should be cyclical and predictable and cover more than 100 km.

Semaprochilodus brama (Valenciennes, 1850)

Prochilodus brama Valenciennes in Cuvier and Valenciennes, 1850:82 [type locality: 1′Amazone (= Rio Amazonas), restricted herein to Brazil, Pará, Rio Tocantins, São João do Araguaia (São João das Duas Barras)].—Castelnau, 1855:62, pl. 31: fig. 2 [redescription based upon holotype].—Günther, 1864: 296 [based upon Valenciennes, 1850].—Eigenmann and Eigenmann, 1891: 48 [in listing of South American fishes].—Ulrey, 1895:259 [Brazil, Rio Tocantins, Trocera].—Gill, 1896:209 [details of skull anatomy].—Eigenmann, 1910:424 [in part, Amazon basin, not citation of species for Rio Orinoco basin].—Bertin, 1947:35 [holotype depository].—Fowler, 1950:216 [literature compilation]; 1975:358 [literature compilation].—Géry, 1964b:467 [Brazil, upper Rio Araguaia]; 1977:219 [as very close to Prochilodus mariae].— Mago-Leccia, 1972:47 [use of caudal-fin pigmentation to distinguish species groups].—[Not Peters, 1877:477 [purported occurrence of species in Rio Orinoco basin].]

Semaprochilodus squamilentus Fowler, 1941:172, fig. 83 [type locality: Rio Parnahyba, Therezina, Piauhy, eastern Brazil (=Rio Parnaiba, Terezina, Piaui, Brazil), corrected herein to Brazil, Rios Tocantins and/or Xingu]; 1950: 227 [literature compilation]; 1975:361 [literature compilation].—Mago-Leccia, 1972:58 [as species of Semaprochilodus].— Roberts, 1973b:213 [originally reported type locality questioned].—Géry, 1977:218 [eastern Brazil].—Böhlke, 1984:148 [holotype and paratype depository; problematic type locality noted].—Mérona, 1987:120 [Brazil, lower Rio Tocantins; ecology].—Castro, 1988:504 [comparison with Semaprochilodus varii].

Prochilodus squamilentus.— Fowler, 1941:171 [cited as type species of genus Semaprochilodus proposed on same page, apparent error].—Böhlke, 1984:148 [erroneous use of Prochilodus rather than Semaprochilodus by Fowler (1941) noted].

Semaprochilodus brama.— Santos et al., 1984:27 [Brazil, Rio Tocantins; commercial importance; life history].—Nomura, 1984:58 [Brazil, common name].—Mérona, 1987:120 [Brazil, lower Rio Tocantins; ecology].—Braga, 1990:549, table 1 [Brazil, Rio Tocantins; feeding and reproduction].—Menezes and Vazzoler, 1992:63 [reproductive characteristics].

DIAGNOSIS.—Semaprochilodus brama is distinguished from all congeners except S. varii and S. laticeps in having the membranous border of the opercle and the exposed portion of the pectoral girdle intensely pigmented with black. It can be readily distinguished from S. varii in the number of scales along the lateral line (56 to 68 versus 39 to 41, respectively), the number of horizontal rows of scales between the dorsal-fin origin and the lateral line (11 to 13 versus 8, respectively), and the number of horizontal rows of scales around the caudal peduncle (23 to 27 versus 16, respectively); and from S. laticeps in the number of horizontal rows of scales between the anal-fin origin and lateral line (10 to 12 versus 8 or 9, respectively) and in the number of scales along the lateral line (56 to 68, 58 most frequent and 56 in only 4 of 26 specimens examined for this feature, versus 48 to 56, 51 most frequent and 56 in only 2 of 27 specimens examined for this feature, respectively).

DESCRIPTION.—Morphometric and meristic data for Semaprochilodus brama presented in Table 18. Body high and compressed; greatest body depth at dorsal-fin origin. Dorsal profile of head concave. Predorsal profile of body convex, distinctly posteroventrally inclined at dorsal-fin base; body profile straight between posterior of dorsal-fin base and adipose-fin origin, and concave along caudal peduncle. Predorsal portion of body with middorsal ridge. Postdorsal portion of body transversely rounded. Ventral profile of body strongly convex from posterior portion of lower jaw to anal-fin base. Ventral profile of caudal peduncle concave. Prepelvic region transversely flattened proximate to pelvic-fin insertion. Well-developed median keel present between pelvic-fin insertion and anus.

Head pointed in lateral profile. Mouth terminal. Snout length slightly greater than, or equal to, horizontal width of orbit; nares on each side of head close to each other; anterior nares circular, posterior nares crescent shaped. Adipose eyelid present, but poorly developed; most developed anteriorly but with much of eye uncovered. Lips fleshy, less developed than in Ichthyoelephas and Prochilodus, but forming oral disk when mouth protracted.

Functional teeth in two rows in each jaw. All teeth movably implanted in flesh that overlies jaws. All teeth of similar size, with exposed portions spoon shaped except when worn down. Inner tooth series of each jaw with 8 to 11 teeth on left side of upper jaw and 5 to 9 teeth on left side of lower jaw. Outer row of teeth in each jaw with approximately 76 teeth on each side of upper jaw and approximately 65 teeth on each side of lower jaw in lectotype of S. squamilentus. Upper and lower lips bordered by numerous globular, fleshy papillae.

Scales cycloid. Lateral line with 56 to 68 (29.6% of specimens with 58) pored scales; 11 to 13 (62.9% of specimens with 12) horizontal rows of scales between dorsal-fin origin and lateral line; 12 to 14 (66.7% of specimens with 13) horizontal rows of scales between pelvic-fin insertion and lateral line; 10 to 12 (70.4% of specimens with 11) horizontal rows of scales between anal-fin origin and lateral line; 13 to 18 (33.3% of specimens with 15) median predorsal scales; 15 to 19 (40.0% of specimens with 17) horizontal rows of scales in middorsal series between posterior of dorsal-fin base and adipose-fin origin; 23 to 27 (48.1% of specimens with 24) horizontal rows of scales around caudal peduncle.

Dorsal fin preceded by small, but well-developed, anteroventrally bifurcate, procumbent spine somewhat triangular in lateral view. Dorsal-fin rays (including procumbent spine) iii,10 [iii,10]; anal-fin rays iii,8 [iii,8]; pectoral-fin rays i,13 to 17 (i,15 most frequent) [i,14]; pelvic-fin rays i,8 [i,8]; principal caudal-fin rays 10/9 [10/9].

Vertebrae 36 or 37 (84.0% of specimens with 37).

Dorsal fin distally pointed; posterior unbranched and anterior branched rays longest and subequal. Dorsal-fin origin closer to tip of snout than to caudal-fin base. Greatest length of adipose fin approximately two-thirds of horizontal width of orbit. Adipose-fin origin located approximately at vertical that passes though middle of anal-fin base. Pectoral fin distally pointed. Tip of adpressed pectoral fin reaching, or almost reaching, pelvic-fin insertion. Pelvic fin falcate. Pelvic-fin insertion located slightly posterior of vertical that passes through dorsal-fin origin. Tip of adpressed pelvic fin reaching posteriorly to region from one-half distance from fin insertion to anus to as far as middle of anal-fin base. Axillary scale present, its length approximately one-fourth or less of greatest length of pelvic fin. Posterior unbranched and anterior branched anal-fin rays longest and subequal. Caudal fin moderately bifurcate.

COLORATION IN ALCOHOL.—Ground coloration golden brown or silvery brown, with dorsal portions of head and body darker. Lateral surface of body with approximately 8 to 16 dark, wavy, horizontal stripes along dorsal and ventral margins of exposed portions of scales. Four to 7 wavy stripes dorsal to, and 4 to 9 wavy stripes ventral to, lateral line. Dense field of brown or black chromatophores forming dark, well-defined area on membranous posterior portion of opercle and on exposed lateral surface of pectoral girdle.

Dorsal fin with 3 to 5 (most frequently 3) dark, irregular stripes beginning on anterior margin of fin and extending across fin approximately parallel to base of fin. Adipose fin with dorsal margin finely outlined with black. Pectoral and pelvic fins hyaline. Base coloration of anal fin hyaline with fields of dark chromatophores forming 1 to 4 (most frequently 3) irregular oblique stripes across fin, with anterior stripes that run in parallel. Caudal fin with 7 to 10 (most frequently 8) dark stripes; 1 horizontal stripe extending over middle caudal-fin rays, with 3 to 5 (most frequently 4) oblique stripes on upper lobe of caudal fin and 3 to 5 (most frequently 3) oblique stripes on lower lobe of fin. Larger and older specimens with pattern of dark stripes across caudal and anal fins becoming fainter, sometimes to point of being almost imperceptible. Iris reddish brown, with diffuse darker areas on dorsal and ventral portions.

COLORATION IN LIFE.—(Based upon photographs of recently captured specimens from the Rio Xingu basin provided by Jansen A.S. Zuanon, INPA). Overall pigmentation bright silvery, darker dorsally on body and particularly on postorbital portion of head. Dark band along margin of opercle particularly apparent. Pelvic fins reddish. Anal fin reddish on distal portions of middle fin rays (full extent of red pigmentation cannot be determined because of damage to fin). Caudal fin with reddish band extending across most of posterior one-half of fin, but with red pigmentation separated from distal margin of fin by hyaline bar. Hyaline region about two-thirds of eye diameter and with distinct posterior margin in upper lobe of caudal fin. Red pigmentation less obvious on lower lobe of caudal fin and with less distinct border relative to distal hyaline bar.

DISTRIBUTION.—Semaprochilodus brama is apparently limited to the clear-water Rio Xingu and Rio Tocantins basins, Brazil (Figure 61, diamonds).

COMMON NAME.—Jaraqui (Brazil).

COMPARISONS.—A noted in the “Diagnosis,” above, Semaprochilodus brama is unequivocally distinguishable from all congeners on the basis of details of various pigmentation and diverse meristic features.

BIOLOGY AND FISHERIES.—According to Mendes dos Santos et al. (1984:27), Semaprochilodus brama demonstrates a complex migration pattern associated with reproduction and feeding. The species is very important in the commercial fishery in the Rio Tocantins basin, accounting for 15% of the total commercial landings.

MATERIAL EXAMINED.—64 specimens (26, 65.9–303.6 mm SL).

BRAZIL. Goiás: Rio Araguaia, near Aruanã (14°58′S, 51°24′W), USNM 191636, 1 (65.9) [1R], Lago Rico, near Cocalinho, Rio Araguaia, MZUSP 21537, 3 (2, 241.7–287.5) [2R]. Mato Grosso: Santa Terezinha, Rio Araguaia, MZUSP 20835, 1 (1, 99.4) [1R], Pará: Baião, Rio Tocantins, UMMZ 203535, 2 (2, 98.7–112.4) [2R]. Igarapé do Limão, Rio Tocantins, Baião, MZUSP 21260, 4 (4, 85.3–115.3) [4R]. Marginal lagoon of Rio Tocantins, near Baião, MZUSP 21266, 4 (1, 90.5–113.6). Lago Trocará, below Tucuruí (approximately 3°42′S, 49°47′, W), MZUSP 21340, 1 (1, 191.0). Small lagoon near Tucuruí, Rio Tocantins (3°42, S, 49°47′, W), MZUSP 21331, 5 (5, 108.9–120.1) [5R]. Igarapé Aricurá, Cametá, MZUSP 21257, 5 (82.4–120.7). Igarapé Maloca, Rio Tocantins, near Cametá (2°15′S, 49°30′W), MZUSP 21254, 8 (2, 72.7–96.2), MZUSP 42716, 2 (cleared and counterstained for bone and cartilage). Marginal lagoon of Igarapé Mura, Rio Tocantins, below Tucuruí (approximately 3°42′S, 49°47′W), MZUSP 21286, 1 (1, 105.9). São João do Araguaia (previously named São João das Duas Barras), Rio Tocantins, MNHN A.1066, 1 (1, 303.6, holotype of Prochilodus brama). Abaetetuba (market), MZUSP 21240, 7 (134.6–147.0). Paraná Samuuma, mouth of Rio Tocantins, MZUSP 21251, 7 (126.3–145.4). Igarapé Oxipucu, Mocajuba, Rio Tocantins, MZUSP 21259, 2 (2, 112.0–124.8) [2R], Igarapé Pindobazinho, mouth of Rio Tocantins, MZUSP 21248, 2 (2, 126.8–130.3) [2R]. Cachoeira do Espelho, Rio Xingú, MZUSP 36852, 4 (2, 181.8–207.6) [2R], Igarapé Sororoca, furo de Panaquera, MZUSP 21243, 1 (164.3). Erroneous Locality: “Rio Pamahyba, Therezina, Piauhy, eastern Brazil” (=Rio Parnaiba, Terezina, Piauí, Brazil; corrected herein to Brazil, Rios Tocantins and Araguaia), ANSP 69480, 1 (1, 117.0, holotype of Semaprochilodus squamilentus; see under “Remarks,” above, concerning apparently erroneous purported type locality) [1R]; ANSP 69481, 1 (1, 122.1, paratype of Semaprochilodus squamilentus, see under “Remarks,” above, concerning apparently erroneous purported type locality) [lR]. Inexact Locality: Barcarena fish market (specimen said to have originated in the Rio Tocantins), USNM 295160, 1