Prochilodus mariae Eigenmann 1922

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

Prochilodus mariae Eigenmann, 1922

Prochilodus brama [not of Valenciennes, 1850].—Peters, 1877:472 [Venezuela, Calabozo].—Eigenmann, 1910:424 [in part, Río Orinoco citation]; 1912:67 [Río Orinoco basin].

Prochilodus mariae Eigenmann, 1922a:231 [type locality: Barrigón, Río Meta (= Colombia, Río Meta, Barrigón)]; 1922b:163 [Spanish version of Eigenmann, 1922a].—Fowler, 1942:133 [Colombia, Río Meta].—Mago-Leccia, 1970:31 [Venezuela]; 1972:48, figs. 5a, 6 [redescription, Río Orinoco basin]; 1978:15 [Venezuela].—Cala, 1977:9 [Colombia, eastern llanos, Río Meta].—Géry, 1977:219 [Río Orinoco].—Novoa R. et al., 1982:276 [Venezuela, Río Orinoco; life history information, major importance in fisheries].—Saldaña and Venables, 1983:617 [migration, energy compartmentalization].—Lowe-McConnell, 1984:143 [economic importance].—Taphorn and Lilyestrom, 1984b:70 [Venezuela, Apure].—Flórez, 1985:9 [Colombia, Río Metica].—Machado-Allison, 1987:25 [Venezuelan llanos]; 1992:48 [larval ecology, Río Orinoco basin].—Machado-Allison et al., 1987:134 [Venezuela, natural history, llanos]; 1990:414 [Venezuela, ecology].—Lasso, 1988:133 [lower Río Orinoco]; 1992:15 [Venezuela, Río Suapure; ecology].—Menezes and Vazzoler, 1992:62 [reproductive characteristics].—Taphorn 1992:483 [Venezuela, Río Apure basin; life history].—Balbás and Taphorn, 1996:78 [Venezuela, Río Caura].—Flecker 1996:1845 [Venezuela; importance in determining community structure and ecosystem attributes].—Winemiller et al., 1996:38, fig. 5a [Venezuela; economic importance; deleterious impact of human activities on populations].—Taphorn et al., 1997:79 [Venezuela].—Barbarino Duque et al., 1998:33 [deleterious impacts of impoundments and over fishing on populations of P. mariae in western Venezuela].—Machado-Allison et al., 1999:66 [Venezuela, Río Caura basin].—Mojica-C., 1999:554 [Colombia, Río Orinoco, Río Inirida, Río Guaviare, Río Cusiana, Río Meta, Río Arauca].—Ponte J. et al., 1999:42 [Venezuela, delta of Río Orinoco].

(?) Prochilodus asper [not of Lütken, 1875].—Fernández-Yépez, 1969:55 [Venezuela, Río Caroni].

DIAGNOSIS.—The dark, irregular, wavy, bar-like patterns on the caudal-fin lobes in Prochilodus mariae discriminates that species from P. argenteus, P. britskii, P. costatus, P. hartii, P. lineatus, P. magdalenae, P. reticulatus, and P. vimboides, which have hyaline caudal fins. Prochilodus mariae is distinguished from all of its congeners that also have irregular, dark caudal-fin bars (P. brevis, P. lacustris, P. nigricans, P. rubrotaeniatus) by the number of scales along the lateral line (52 to 64, 52 in only 1 of 39 specimens examined for this feature, versus 41 to 51 in those four species in combination, with 51 in only 2 of 50 specimens of P. lacustris of northeastern Brazil examined for this feature, respectively). Prochilodus mariae further differs from P. lacustris in the number of rows of dark, wavy, horizontal stripes ventral of the lateral line (6 or 7 versus 7 to 10, respectively) and in the mode and the number of median scales between the posterior of the dorsal-fin base and the adipose-fin origin (17 to 23, 18 and 19 most frequent, versus 14 to 18, 16 most frequent, respectively).

DESCRIPTION.—Morphometric and meristic data for Prochilodus mariae presented in Table 13. Body comparatively high, transversely compressed. Greatest body depth at dorsal-fin origin. Dorsal profile of head gently concave. Predorsal profile of body convex. Body profile posteroventrally inclined along dorsal-fin base; straight from posterior of dorsal-fin base to adipose-fin origin, and concave along caudal peduncle. Predorsal portion of body with slight median ridge. Postdorsal portion of body obtusely rounded transversely. Ventral profile of body moderately convex from tip of lower jaw to posterior of anal-fin base. Ventral profile of caudal peduncle concave. Prepelvic region of body transversely flattened proximate to pelvic-fin insertion. Distinct midventral keel present between pelvic-fin insertion and anus.

Head profile pointed. Mouth terminal. Snout length greater than horizontal width of orbit. Nares of 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 greater part of eye uncovered. Lips fleshy, moderately developed relative to those in some other prochilodontids, and forming oral disk when 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 in each jaw with 15 to 25 teeth on left side of upper jaw and 8 to 14 teeth on left side of lower jaw. Outer row of teeth in each jaw with approximately 100 teeth on each side of upper jaw and approximately 89 teeth on each side of lower jaw in holotype. Upper and lower lips bordered by numerous globular, fleshy, papillae.

Scales spinoid. Scales in middorsal series between posterior of dorsal-fin base and adipose-fin origin similar in form to those of adjoining regions of body. Lateral line with 52 to 64 (25.6% of specimens with either 58 or 59) pored scales; 10 or 11 (66.7% of specimens with 11) horizontal rows of scales between dorsal-fin origin and lateral line; 8 to 10 (71.8% of specimens with 9) horizontal rows of scales between pelvic-fin insertion and lateral line; 7 or 8 (71.8% of specimens with 7) horizontal rows of scales between anal-fin origin and lateral line; 17 to 22 (22.2% of specimens with 21) median predorsal scales; 17 to 23 (59.4 specimens with either 18 or 19) scales in middorsal series between posterior of dorsal-fin base and adipose-fin origin; 17 to 19 (84.6% of specimens with 18) 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,7 or 8, or ii,7 (iii,8 most frequent) [iii,8]; pectoral-fin rays i,12 to 17 (i,15 most frequent) [i,16]; pelvic-fin rays i,8 [i,8]; principal caudal-fin rays 10/9 [10/9].

Vertebrae 40 to 42 (75.0% of specimens with 41).

Dorsal fin truncate and slightly pointed distally; posterior unbranched and anterior branched longest and subequal. Dorsal-fin origin located closer to tip of snout than to caudal-fin base. Greatest length of adipose fin approximately equal to horizontal width of orbit. Adipose-fin origin situated along vertical that passes through anterior one-third of anal-fin base. Pectoral fin pointed distally. Tip of adpressed pectoral fin reaching posteriorly to, or almost to, pelvic-fin insertion. Pelvic fin falcate. Pelvic-fin insertion located along vertical that passes approximately through middle of dorsal-fin base. Tip of adpressed pelvic fin reaching posteriorly approximately four-fifths of distance between pelvic-fin insertion and anus. Axillary scale present, its length approximately one-fourth 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 silvery yellow or brownish yellow, with dorsal portion of body and head darker. Lateral portion of body typically with 10 to 16 vertical, diffuse, and irregular patches of dark pigmentation between head and caudal fin. Patches with approximate overall form of narrow isosceles triangles with apexes positioned along middle of ventrolateral portion of body and bases along dorsomedial region. Patches well developed in smaller specimens, but indistinct or absent in larger individuals. Lateral surface of body with approximately 12 to 14 dark, wavy, horizontal stripes along dorsal and ventral margins of exposed portions of scales. Approximately 6 or 7 wavy stripes dorsal to, and 6 or 7 wavy lines ventral to, lateral line. Field of black or brown chromatophores forming dark, irregular mark on dorsal one-half of opercle.

Dorsal fin with 5 to 7 (most frequently 5) irregular dark stripes beginning at anterior margin and extending across fin approximately parallel to base of fin. Adipose fin with diffuse dark spots and dorsal margin finely bordered by black. Pectoral, pelvic, and anal fins dusky. Caudal fin with 3 to 5 (most frequently 3) [5] irregular, wavy, dark bars formed by groups of chromatophores. Iris brownish orange, with diffuse dusky areas on dorsal and ventral portions.

DISTRIBUTION.—Prochilodus mariae is endemic to the Río Orinoco basin in Colombia and Venezuela and Río Casiquiare in Venezuela that drains into the upper Río Negro of the Río Amazonas basin (Figure 52, dots).

COMMON NAME.—Coporo de los Llanos (Venezuela).

BIOLOGY AND FISHERIES.—Flecker (1996:1845) demonstrated that the species is a functionally dominant species in the Andean foothill streams of the Río Orinoco basin. In his study, the experimental removal of all individuals of Prochilodus mariae from within artificial enclosures in that ecosystem resulted in dramatic shifts in both community structure and ecosystem attributes.

Prochilodus mariae is one of the most important species in the fisheries of the Río Orinoco basin. Novoa R. et al. (1982:277) reported that P. mariae accounts for 15% of the total commercial fish landings at various localities in the Río Orinoco delta.

COMPARISONS.—As detailed in the “Diagnosis,” Prochilodus mariae is readily distinguishable from its congeners by a combination of meristic characters and details of pigmentation.

MATERIAL EXAMINED.—338 specimens (40, 29.6–366.5 mm SL).

COLOMBIA. Meta: Lago Mozambique, Hacienda Mocambique, ANSP 128143, 1 (1, 366.5); ANSP 128144, 1 (1, 341.0); ANSP 128786, 1 (1, 29.6); ANSP 135576, 4 (266.8–355.3) [IR]. Río Metica, approximately 3 km SE Hacienda Mozambique, ANSP 135557, 1 (1, 202.9); ANSP 135823, 1 (1, 231.0). Quebrada Venturoza, between La Balsa and Puerto López, ANSP 137763, 1 (1, 121.1). Lago Mozambique, Hacienda Humacita, ANSP 128784, 1 (1, 148.4). Río Negrito, bridge on road joining Puerto López to Villavicencio, ANSP 146861, 1 (131.5) [1R]. Garazoa, N of Villavicencio and Guaicaramo, USNM 100772. Río Meta, Barrigón (4°10′N, 73°01′W), CAS 15150, 1 (1, 234.0, holotype of Prochilodus mariae, formerly IU 15150, in part) [1R]; CAS 23942, 1 (1, 225.6, paratype of Prochilodus mariae, formerly IU 15150, in part) [1R]. Río Guaviare, FMNH 73418, 6 (1, 88.0–143.3) [1R]; USNM 181365, 4.

VENEZUELA. Amazonas: Río Orinoco, El Burro, ANSP 158863, 30 (2, 81.0–117.8); lots ANSP 158866 (2 specimens) and ANSP 158868 (7 specimens) intermingled =9 (1, 111.1–144.4). Caño Orera, close to El Burro, ANSP 158870, 4 (2, 89.4–113.8). Río Meta, approximately 20 minutes upriver of confluence with Río Orinoco, ANSP 158853, 29 (3, 98.4–286.6); ANSP 158854, 6 (244.6–305.8). Río Casiquiare, mouth of Río Curamuni, CAS-SU 56804, 2 (1, 107.9–108.6) [1R]. Río Mavaca, upstream of base camp, AMNH 93102, 2 (200.1–207.8). Apure: Río Apure, 10 km SW of San Fernando de Apure, CAS 34377, 3 (135.8–159.5). Río Apure, San Fernando de Apure, CAS-SU 56719, 9 (94.6–122.4). Río Apure, approximately 3 km W of fisheries station in San Fernando de Apure, MZUSP 27965, 12 (2, 88.5–116.9). Río Apure, Hacienda La Guanota near San Fernando de Apure, LIRP 1310, 8 (1, 35.3–79.4). Caño Cai-cara, at bridge on road from Montecal (7°22′N, 69°21′W), AMNH 77823, 26 (95.8–138.8). Río Apure (Las Guanotas), near San Fernando de Apure, USNM 256959, 10 (18.5–34.5; specimens cleared and counterstained for bone and cartilage). Río Apure, San Fernando de Apure, LIRP 1310, 8. Bolivar: Caño Caiman, where crossed by road between Caicara and Puerto Ayacucho, ANSP 158867, 4 (1, 119.6–145.3). Laguna La Teja, Caicara, CAS-SU 56716, 1 (152.2). Caño Quiribana, Caicara, CAS-SU 56806, 1 (115.3); CAS-SU 56809, 4 (119.0–134.2); CAS-SU 56811, 1 (131.3); CAS 58895, 2 (131.3–147.3). Small caño connected with Río Orinoco at El Burro, USNM 270243, 37 (3, 77.2–131.0). Small caño tributary to Río Mato, ANSP 13984, 1 (1, 154.5). Río Agua Blanca, near highway between Caicara and Ciudad Bolivar, ANSP 158857, 15 (1, 110.1–156.4). Río Urbana, on road between Maripa and Las Trincheras, ANSP 135780, 1 (145.3). Río Chaviripa, 15 km N of Manipure on road between Caicara and Puerto Ayacucho, ANSP 158856, 8 (1, 136.5–152.8). Río Orinoco, close to Puerto Las Majadas, ANSP 158865, 1 (140.5). Delta Amacuro: Mouth of caño Anabata, in front of Isla Portuguea, ANSP 150097, 3 (1, 232.3–246.1). Guárico: Tributary of Río Guariquito, 24 km SSE on road to Cazorla, ANSP 130042, 4 (1, 103.0–109.8). Río Guariquito, MBUCV V-2499, 8. Río Orituco, 15 km SEE of Calabozo on road between Calabozo and Cazorla, ANSP 146530, 61 (1, 55.9–256.0). Monagas: Río Orinoco, laguna Tapatapa on Isla Tapatapa, USNM 222839, 2 (1, 123.7–178.8). Río Guarapiche, Caicara, USNM 163157, 1.