Brycon falcatus (Lima, Flávio C. T. 2017)
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- Brycon falcatus Lima, Flávio C. T., 2017, Zootaxa 4222: 142-158.
Brycon sp. (B. falcatus group): Toledo-Piza, 2002: 116 –117 (drawing by A.R. Wallace; “ Rio Uaupés”; common name). Brycon carpophagus (not Valenciennes): Mérona et al., 2001: 387, 391 (Rio Tocantins, Tucuruí; diet before and after river impoundment).
Diagnosis.Brycon falcatus can be distinguished from all remaining cis-andean Brycon species, with the exception of B. gouldingi, by typically possessing a V- or crescent-shaped dark blotch on caudal peduncle and caudal fin. Brycon falcatus can be distinguished from B. gouldingi by possessing possessing dark, longitudinal stripes formed by pigmentation concentrated on the mid-distal portion of scales (vs. dark, wavy longitudinal stripes formed by dark pigment concentrated on upper and lower scale margins), paired fins typically clear (vs. paired fins black), and lower lateral line scale counts (47–69, modally 57, vs. 66–82, modally 74). Brycon falcatus is morphologically more similar to B. melanopterus, and an unequivocal diagnosis between both species based only on external morphological characters is not possible due to the great polymorphism in color pattern observed in the species. However, typically, Brycon falcatus does not present an oblique dark solid stripe, presenting instead a V or crescent-shaped blotch on caudal fin (vs. black pigmentation restricted to the upper caudal-fin lobe in B. melanopterus). In addition, Brycon falcatus is typically a higher bodied fish, with higher vertebrae counts. See the item “Comparisons” under Brycon melanopterus, and the item “Variation”, below, for thorough account on the subject.
Description. Morphometric data are presented in Tables 21–22; some meristic data (lateral line counts and scales between dorsal-fin origin and lateral line) in Tables 23–24. Middle- to large-sized species, largest examined specimen 434.7 mm SL. Body moderately slender to high. Largest body height slightly ahead of dorsal-fin origin. Dorsal body profile slightly convex from upper lip margin to vertical through anterior naris, straight to moderately convex from latter point to basis of supraoccipital process, moderately to pronouncedly convex from latter point to dorsal-fin origin, straight along dorsal-fin basis, and straight to slightly convex from dorsal-fin basis to adipose-fin origin. Dorsal profile of caudal peduncle slightly concave. Ventral profile slightly to pronouncedly convex from lower lip to pelvic-fin insertion, straight to slightly convex from this point to anal-fin origin and approximately straight along anal-fin base. Ventral profile of caudal peduncle slightly concave. Head profile slightly acute anteriorly, snout obtuse, mouth terminal. Jaws approximately isognathous to slightly anisognathous, outer row of premaxillary teeth partially exposed when mouth is closed. Maxillary moderately long, extending posteriorly to anterior third of pupil. Adipose eyelid well developed. Premaxillary teeth in three rows; teeth of third row largest. Five (2), 6 (5), 7 (29), 8 (65), 9 (118), 10 (99), 11 (53), 12 (8), or 13 (1) relatively small tricuspidate teeth in outer series. Three (30), 4 (229), 5 (107), 6 (6), or 7 (1) tri- to pentacuspidate teeth in second, inner premaxillary row, plus 2 (2), 3 (150), 4 (218), or 5 (7) tricuspidate teeth between the first and third rows. Two teeth in third premaxillary row, medial teeth largest, symphyseal teeth smaller, slightly tilted towards each other, both pentacuspidate. Maxillary margins approximately parallel, straight in profile. Fifteen to 28 maxillary teeth, slightly smaller than teeth of first premaxillary row, anterior teeth tricuspidate, posterior teeth unicuspidate. Dentary with 7 (7), 8 (34), 9 (72), 10 (61), 11 (26), 12 (9), 13 (3), 14 (1), or 15 (1) teeth in main series. Anterior four dentary teeth assymetrical, considerably larger and bulkier than remaining teeth, pentacuspidate, each with central cusp distinctly larger than remaining cusps. Remaining dentary teeth progressivelly smaller, penta- to unicuspidate. Inner (lingual) series consisting of a small, single unicuspid symphyseal tooth, situated immediately posterior to symphyseal dentary teeth of main series, plus row of 13–21 small, aciculated, unicuspidate teeth, originating on lingual crest of dentary replacement trench at the level of fourth to seventh main series dentary teeth. Symphyseal teeth may be lacking in larger (> 350 mm SL) specimens.
n Range Mean Standard length (SL)385 84.6–434.7-Percentages of standard length Depth at dorsal-fin origin379 28.8–42.8 36.4Snout to dorsal-fin origin384 46.9–56.6 50.6Dorsal-fin base length384 7.1–15.6 12.8Posterior terminus of dorsal fin to adipose fin385 20.5–28.9 24.5Posterior terminus of dorsal fin to hypural joint385 32.3–43.2 36.8Snout to pelvic-fin insertion385 45.2–54.6 48.9Snout to anal-fin origin384 65.0–75.7 69.9Anal-fin base length383 18.7–26.3 23.1Caudal peduncle length379 10.1–17.3 14.0Dorsal-fin height374 17.7–26.8 23.0Pectoral-fin length378 14.0–24.2 20.1Pelvic-fin length373 9.7–20.9 17.6Caudal peduncle depth380 8.4–13.1 10.0Head length388 22.5–32.2 26.0Percentages of head length Head height382 76.7–1.14 90.6Snout length385 22.2–37.2 29.6Upper jaw length385 38.1–51.4 46.2Horizontal eye diameter385 20.9–41.7 30.3Post-orbital length385 36.9–52.2 43.7Least interorbital width385 31.1–53.6 41.3 Scales cycloid. Lateral line complete, from supracleithrum to caudal-fin base. Forty-seven (1), 48 (1), 49 (1), 50 (3), 51 (11), 52 (25), 53 (57), 54 (59), 55 (77), 56 (90), 57 (104), 58 (93), 59 (57), 60 (49), 61 (27), 62 (14), 63 (8), 64 (16), 67 (1), or 69 (1) scales in lateral line series. Laterosensory tube simple in specimens smaller than 100 mm SL, ramified in specimens larger than 100 mm SL. Tubules ramification increasing in complexity along ontogeny, specimens up to 150 mm SL with tubules with two or three branches, three to six branches in specimens between 150–250 mm SL, and with more than 10 branches and developing a dendritic pattern of ramification, with tubules often overlapping each other in larger (> 270 mm SL) specimens. Horizontal scale rows between dorsal-fin origin and lateral line eight (1), 9 (21), 10 (115), 11 (122), 12 (103), 13 (29), or 14 (3). Horizontal scale rows between lateral line and pelvic-fin 4 (21), 5 (156), 6 (169), 7 (27), or 8 (1). Circumpeduncular scales 15 (1), 16 (27), 17 (75), 18 (125), 19 (67), 20 (51), 21 (32), or 22 (6). Dorsal-fin rays ii, 9. Dorsal fin origin slightly ahead, or about at middle of SL. First dorsal-fin pterygiophore inserting behind neural spine of 11th (2), 12th (1), or 13th(1) vertebra. Anal-fin rays iii (not including first, small unbranched ray only visible in cs specimens), 18 (1), 19 (4), 20 (11), 21 (41), 22 (90), 23 (93), 24 (82), 25 (45), or 26 (6). First anal-fin pterygiophore inserting behind haemal spine of 22th (4), or 23th (1) vertebrae. Anal-fin rays decreasing only slightly in size towards anal-fin end. Anal fin displaying several (c. 5–12 per fin-ray main branch) small hooks on posterior main branch of branched rays 2–11, associated with dense, gelatinous tissue in 5 examined specimens (MZUSP 3845, 2, 196.2– 198.9 mm SL, MZUSP 16448, 1, 196.5 mm SL mm SL, MZUSP 91493, 1, 226.0 mm SL, MZUSP 94990, 1, 230.0 mm SL). A single hook per ray segment. Sheath of scales covering basis of anal-fin rays composed of four scale rows, lower scale row formed by 21–25 rectangular scales. Pectoral-fin rays 11 (3), 12 (76), 13 (229), or 14 (58). Pelvic-fin rays typically i, 7 (364), rarely i, 6 (4), or i, 8 (4). Main caudal-fin rays 10/9. Caudal fin forked, lobes slightly emarginated. Laterosensory tube extending over interradial membrane between upper and lower caudal-fin lobes to the distal portion of fin. Laterosensory tube on caudal fin with dorsally and ventrally oriented side branches across its length. Small distal projection in the area of the laterosensory tube present in specimens with relatively intact caudal fin. Four branchiostegal rays, three on anterior ceratohyal and one on posterior ceratohyal. First branchial arch with 12 (14), 13 (24), 14 (40), 15 (32), 16 (22), or 17 (2) lower, 1 at angle, and 11 (1), 12 (15), 13 (38), 14 (51), 15 (20), 16 (6), or 17 (2) upper gill rakers. Vertebrae 39 (1), 40 (1), 41 (7), 42 (5), 43 (2), or 44 (1). Supraneurals 8(2), or 9 (2).
A B C D Standard length (SL)169.5 87.4–92.7 110.0–120.9 149.2Percentages of standard length Depth at dorsal-fin origin -31.2–33.4 31.8–37.6 38.3Snout to dorsal-fin origin50.6 50.6–51.6 50.9–53.9 51.1Dorsal-fin base length13.4 13.3–13.4 12.2–13.1 14.1Posterior terminus of dorsal fin to adipose fin25.4 22.5–24.3 23.0–25.1 27.0Posterior terminus of dorsal fin to hypural joint39.9 36.6–36.8 36.7–41.0 38.9Snout to pelvic-fin insertion -52.9–53.9 53.0–53.6 49.9Snout to anal-fin origin72.9 72.4–73.0 72.1–74.5 69.6Anal-fin base length23.4 21.7–23.3 22.9–23.4 22.9Caudal peduncle length9.0 13.4–14.2 10.8–12.5 15.8Dorsal-fin height -24.7–25.4 22.4–23.2 23.7Pectoral-fin length -18.4–19.6 18.3–20.1 20.2Pelvic-fin length -18.0–18.3 14.4–16.3 15.8Caudal peduncle depth9.8 9.0–9.9 9.5–10.2 11.0Head length23.7 29.7–30.0 28.1–29.4 26.1Percentages of head length Head height -23.1–23.8 78.3–84.4 89.5Snout length28.4 27.0–30.0 28.8–31.7 30.3Upper jaw length48.9 46.8–48.8 48.9–50.0 47.7Horizontal eye diameter29.9 30.9–32.3 28.7–30.3 28.7Post-orbital length45.6 41.9–42.4 42.9–46.2 45.6Least interorbital width42.1 35.6–37.3 37.2–44.1 46.2 Coloration in alcohol. Top of head, snout, supraorbital, and sixth infraorbital light-grey to light-brown. Dorsal portion of body light-grey to dark-brown. Second, third, fourth, and fifth infraorbitals, opercle and cleithrum silvery in specimens retaining guanine, light-brown in specimens that lost this pigment due to a long storage in formalin. Dentary, maxillary, gular area, and lower portion of body light-brown. Lateral portion of body silvery in specimens retaining guanine, light brown in specimens that lost this pigment due to a long storage in formalin. Humeral blotch present, slightly to moderately conspicuous, approximately rounded in shape, situated immediately above lateral line, its anterior margin at level of second, extending longitudinally to posterior margin of fourth to fifth lateral line scales, and vertically one and half scales high. Scales on lateral portions of body with dark pigmentation concentrated on their central portion, forming dark, straight longitudinal stripes, more conspicuous dorsally. Dark, solid, oblique dark stripe extending along anal-fin scales sheath and anal-fin basis in almost all specimens (see item “Variation”, below). Caudal peduncle blotch wide, extending across upper and lower caudalfin rays typically as a V- or crescent-shaped dark blotch, though with a great degree of variation in the development of the pigmentantion in the lower caudal-fin lobe (see item “Variation”, below). Dorsal, anal, pectoral, and pelvicfin rays with a variable amount of interradial dark pigmentantion but typically clear. Adipose-fin light- to darkgrey, with scattered dark spots in large specimens from the upper rio Tapajós basin.
Color in life. Description based on pictures of several specimens collected at the lower rio Japurá (Lago Amanã), upper rio Madeira, upper rio Tapajós, upper rio Xingu (Fig. 90), and rio Tocantins in Amazon basin, Río Inirida, Orinoco basin, and Kuribrong River, Essequibo basin, plus published pictures of living specimens (Géry, 1977: 321, upper and lower; Planquette et al., 1996: 227; Ferreira et al., 2007: 125). Top of head and snout light- to dark-grey. Dorsum plumbeous. Lateral surfaces of head and body silvery. Humeral blotch relatively inconspicuous. Dark stripe extending along anal-fin basis and dark, V-shaped caudal peduncle/caudal-fin blotch very conspicuous. Distal border of caudal fin yellowish to reddish. Adipose fin yellowish grey. Remaining fins translucent, dorsal fin with some yellowish pigmentation. Variation.Brycon falcatus is one of the most widespread cis-andean Brycon species, and perharps not unexpextedly, a great degree of variation in body shape and color pattern is observed across its range. Specific features that show a great degree of variation are body height, caudal-fin pigmentation, scale counts, maximum body size, and, to a lesser extent than the previous features, anal-fin pigmentation. Each of these features is treated sequentially below. Body height varies considerably in specimens of Brycon falcatus, to an extent unequalled among cis-andean Brycon species. Specimens range from being relatively elongated (Fig. 89) to high-bodied (Figs. 86, 88, 92). However, there is no consistent geographical variation in this character, and most river systems present specimens ranging from both extremes in body shape. Probably, most of the observed variation in this trait is simply a result of phenotypic plasticity. Caudal-fin pigmentation is the most significant trait to vary among Brycon falcatus populations, and, contrary to body height, exhibits a clear geographical pattern. Brycon falcatus populations from the Guianas, rio Branco, rio Capim, rio Tocantins, and rio Xingu basins possess the characteristic V- or crescent-shaped caudal-fin blotch, with the extent of dark pigmentation approximately symmetrical in both lobes (Figs. 86–87). However, moving westwards into the Brazilian and Guyanese shields, dark pigmentantion on the lower caudal-fin lobe tend to decrease clinally in intensity. Specimens from the rio Tapajós and rio Madeira basins range from possessing an almost symmetrical dark pigmentation in both fin lobes (Figs. 88, 92) to a considerably less pigmented lower caudal-fin lobe. Specimens from the middle and lower rio Negro and middle and middle rio Orinoco basin possess a clearly asymmetrically pigmented caudal fin, with the dark pigmentation much more intense and extensive in the upper, than in the lower caudal-fin lobe (Figs. 93–95). Moving westward into western Amazon, the apparently scattered populations of Brycon falcatus occurring in that vast area possess an even more asymmetrically pigmented caudal-fin, with the lower lobe almost (Fig. 96) or completely (Fig. 97) unpigmented, the latter condition found in specimens from Iquitos area, the most westward known locality for the species. Oddly, specimens from the upper rio Negro (above São Gabriel rapids) and upper rio Orinoco (above its junction with the Río Guaviare) basins present a similar color pattern to the specimens from Iquitos area, presenting no dark pigmentation at all at the lower caudal-fin lobe and the upper caudal-fin lobe pigmentation almost continuous with the anal-fin dark stripe (Fig. 98). Specimens from the Iquitos area and upper rio Negro and upper Río Orinoco basins are thus very similar in color pattern to B. melanopterus, though B. falcatus is typically a higher-bodied species, with lower vertebral counts (see item “Comparisons” of B. melanopterus). See item “Putative examples of mimicry involving Brycon ”, below, for a possible explanation for this similarity. Scale counts vary considerably among distinct populations of Brycon falcatus, with specimens from the Guianas clearly presenting lower counts when compared with specimens from the Orinoco and Amazon basins (see Tables 23 and 24). The lower scale counts presented by Guyanese specimens when compared with specimens from rio Capim and rio Tocantins basins were the main reason supporting the recognition of Brycon brevicauda as a valid species (e.g., Géry, 1964: 450; Howes, 1982: 14). However, the examination of large series of specimens undertook during the present study demonstrated a continuous variation in scale counts among the several populations of Brycon falcatus, thus failing to confirm the presumed distinctness of B. brevicauda based on this character (Tables 23 and 24). Another trait which shows a clear geographical component in Brycon falcatus is the maximum length reached by different populations. Typically, Brycon falcatus is a middle-sized species, generally does not exceeding 300 mm SL (e.g., the maximum size of 350 mm TL reported by Rubio et al., 2012, based on the examination of 279 specimens collected at the rio Guaporé). However, extensive examination of both preserved and unpreserved specimens of Brycon falcatus from the rio Teles Pires and rio Juruena in the upper rio Tapajós basin, and from the upper rio Xingu basin showed that individuals belonging to these populations often grow considerably above this upper limit. Maximum recorded sizes from specimens from these areas are, respectively, 435.0 and 401.0 mm SL, and specimens ranging between 300–400 mm SL are common. To complicate further the issue, in the upper rio Tapajós area apparently both morphotypes (“ large-sized” and “middle-sized”) co-exist (J.M. Mendes and H.F. Mendes, pers. comm.). The “large-sized” population from the upper rio Xingu is slightly different from the one from the upper rio Tapajós in being on average smaller-sized and by not possessing the dotted adipose fin present in the latter.
47 48 49 50 51 52 53 54 55 56 57Guyana and Suriname1 1 2 1 5 10 12 12 6 4 2Orinoco1 5 2 5 3 3Negro1 1 3 5 3 4 6 9Branco1 4 5 4 4 4Tocantins and Capim1 2 1 1 1 4Xingu2 4 5 10 13Tapajós2 3 5 9 13 10Madeira2 4 7 6 8Western Amazon2 1 2 4 4continued. 58 59 60 61 62 63 64 65 66 67 68 69 Guyana and Suriname Orinoco 4 1 1 1 Negro 6 2 1 Branco 4 2 Capim
Orinoco 10 7 1 6 Negro 14 24 1 Branco 12 18 Tocantins and Capim 12 44 4 Xingu 8 11 21 8 Tapajós 2 28 23 25 7 Madeira8 16 11 Western Amazon 4 11 1 2 Brycon falcatus typically possess a conspicuous dark stripe along the basis of anal-fin, the intensity of which, however, varies considerably among populations and even within specimens collected in the same general area. Some specimens from the upper portion of the rio Araguaia in central Brazil (MZUSP 18628, MZUSP 62490, MZUSP 48113, MZUSP 52391) entirely lack the dark stripe. At the other extreme are the specimens from the upper Río Orinoco and upper rio Negro, which possess a very well-developed dark stripe that extends from the origin of the pelvic fin to the caudal peduncle, much as the stripe found in Brycon melanopterus (see above). It is interesting to notice that specimens collected in the rio Arinos at the upper rio Tapajós basin (e.g., MZUSP 56785, MZUSP 60423, MZUSP 61056) possess a well-developed dark stripe, while specimens collected in the same area but kept for some time in fish ponds (MZUSP 61132, MZUSP 61133) lack entirely the dark stripe. This suggests that the expression and the intensity of the dark stripe might vary as a response of some physiological factor. Finally, a considerable molecular divergence among samples the species from the Río Orinoco in Venezuela, rio Negro in Brazil and upper rio Xingu was detected by Abe et al. (2014). Abe et al. (2014: 12) considered that populations of Brycon falcatus from the Río Orinoco and Río Negro basins were separated by the development of the Vaupes arch. However, Brycon falcatus possess a continuous distribution across the upper rio Negro and upper Río Orinoco afforded by the Río Casiquiare, from where the species is known (see Fig. 99), and consequently the genetic divergence between these samples cannot be ascribed to a supposed vicariant event that in fact did not isolated these populations. A much larger sampling is necessary to understand phylogeographical patterns and the possible existence of cryptic species within the populations herein assigned to Brycon falcatus. Until such work is done, it is deemed more parsimonious to consider all these populations as belonging to a single species. Common names. Brazil: “matrinchã”; “ piabanha ” (Santos et al., 1984: 41); “voadeira”, “avoadeira”, “matrinchã-pequena”; “jatuarana-miri” (Wallace, in Toledo-Piza, 2002: 116); “miõ wi” (Tukano language, upper rio Negro basin; Lima et al., 2005: 164); “wenawe” (Tuyuka language, upper rio Negro basin; Lima et al., 2005: 164); French Guiana: “moloko blanc”, “maloko”, “mbooko”, “molokoimo” (Planquette et al., 1996); Suriname: “moroko” (Richter & Nijssen, 1980: 123; Mol et al., 2007: 115); Guyana: “kurumi” (Müller & Troschel, 1845: 29); Venezuela: “palambra”, “bócon” (Taphorn, 1992: 128).
Distribution. Widespread in rivers draining the Brazilian and Guyana shields in the Amazon, Orinoco, and guyanese river systems, and also on scattered localities in western Amazon (Fig. 99). Brycon falcatus is recorded only from clear or dark water rivers and never occur at white/murky-water rivers. Records from the rio Madeira basin are all from shield-draining, clear- to black-water tributaries such as rio Guaporé/Itenez, rio Jamari, rio Aripuanã, and rio Roosevelt. Likewise, records in the western Amazon came from black-water systems as the Lago Amanã near the mouth of rio Japurá in Brazil or the Río Nanay near Iquitos, Peru. From guyanese river systems, we have examined material from the Essequibo, Corantijn, and Maroni/ Marowijne Rivers in Guyana, Suriname and French Guiana, but the species is also reported from the Suriname River (e.g., Richter & Nijssen, 1980; Mol et al., 2007; Mol et al., 2012), Coppename River (Mol et al., 2006; Mol et al., 2012), Nickerie River (Mol et al., 2012) and Saramacca River (Mol et al., 2012) in Suriname, and Mana River (Planquette et al., 1996: 226–227) in French Guiana. The present westernmost record for Brycon falcatus is Iquitos and records from more westward localities (e.g., Ecuador; Gilbert & Roberts, 1971; Saul, 1975) need to be re-examined. Recorded as a vagrant species in a river from southern Trinidad (Phillip et al., 2013: 16; see item “Biogeography”, below). Ecological notes. As noticed above, Brycon falcatus inhabits exclusively clear- or black-water rivers. Like its congeners, Brycon falcatus is a highly mobile fish and utilizes a great variety of habitats, ranging from river channels, flooded forest, floodplain lakes, to small tributaries. The species undertake massive spawning upstream migrations in the rio Culuene, upper rio Xingu basin, during September/November (pers. obs.), but spawning migrations in the rio Araguaia basin appear to be much more discrete and local (J.B. Nunes, pers. comm.). Specimens associated in small groups of up to 3 individuals were observed while snorkelling in clear-water tributaries of the upper rio Arinos, rio Tapajós basin, Mato Grosso during the late wet season (pers. obs.). Lowe Mc-Connel (1964: 118, 120) noticed downstream migration of the species in the Ireng River (upper Rio Branco basin, Guyana) during the early dry season, and specimens with ripening gonads in the Rupununi River in April (early wet season). At the rio Guaporé (Mato Grosso, Brazil), mature females were collected at the beginning of the rainy season, between October and December (Rubio et al., 2012). Scale rings indicated a maximum age of five years in specimens from the rio Guaporé (Rubio et al., 2012). A female with 30 cm SL from the rio Culuene collected early October possessed mature gonads (pers. obs.). Migratory schools in the rio Culuene were observed being attacked by Hydrolycus armatus specimens, and some dying Brycon falcatus were found with deep parallel cuts which very likely were inflicted by this large predatory characin (pers. obs.). An osprey, Pandion haliaetus, was observed with a Brycon falcatus specimen under its talons at the Kuribrong River, Guyana (pers. obs.).
Detailed studies on the diet of Brycon falcatus are Borges (1986), who studied specimens from the middle and lower rio Negro basin in Brazil, and Albrecht et al. (2009), studying specimens from the upper rio Tocantins basin in central Brazil. Borges (1986) found mainly vegetal itens (fruits and seeds) in stomach contents of specimens collected during the rainy season, while during the dry season, arthropods were the main dietary item. Leaves, flowers, and fishes were moderately consumed in both seasons. Fruits commonly found in stomach contents were Ocotea sp. (Lauraceae), Tococa sp. (Melastomataceae), and Macrolobium acacifolium (Fabaceae). Albrecht et al. (2009) also found seeds and fruits to be the most important dietary item for the species, followed by ants, coleopterans, fish and terrestrial vertebrates. Correa & Winemiller (2014) reported that the species switched from fruits and seeds to terrestrial invertebrates as its main dietary item from rainy season to dry season in a site at the lower Río Caquetá basin (= Rio Japurá in Brazil) in Colombia, although later than the syntopic B. melanopterus. Matos et al. (2016) recorded invertebrates (mostly insects and Decapoda), fishes, flowers, seeds and fruits as the main itens ingested by Brycon falcatus at the rio Teles Pires basin, and that specimens living in river stretches where an artificial food supply (soybeans and corn) was provided presented a better condition (i.e., more abdominal fat) than specimens living in river stretches where no artificial food supply was provided.
Remarks. Jardine, in Jardine & Schomburgk (1841: 212–213) described Chalceus labrosus from the “river Paduiri” (= Rio Padauari), a locality which lies in the middle rio Negro basin, Amazonas, Brazil, an area visited by Schomburgk in March 1839 (Schomburgk, 1840). No type material is known for this nominal species. Though poor, the description and plate of Chalceus labrosus clearly correspond to the same species latter described by Müller & Troschel as Brycon falcatus. Jardine, in Jardine & Schomburgk (1841: 212–213) mentions the three series of teeth in the premaxillary (“three rows on the roof of the mouth”), the dark stripe at the basis of anal fin (“a broad black mark running from the centre of its anterior edge for one-third of its length”), and the crescent-shaped blotch at the caudal fin (“a dark bluish black bar running across, parallel to the fork”). The name Chalceus labrosus was never used as a valid species after its original description, while Brycon falcatus has been continuously used in the ichthyological literature during the last 160 years, by well more than 25 authors (see synonymic list, above). We consider thus that Chalceus labrosus fulfills the necessary requisites to be considered as a nomen oblitum (Article 23.9.1 of the International Code of Zoological Nomenclature, 1999), and, as such, as not having precedence over Brycon falcatus, which is herein considered a nomen protectum. Müller & Troschel (1844: 90) briefly described Brycon falcatus, based on an unspecified number of syntypes collected at Guiana and Suriname by Schomburgk and Dieppering. A little later, the same authors (Müller & Troschel, 1845: 29, pl. 6, fig. 1) described the species in detail and provided a good illustration of it. Though the type specimens were not examined in the present study, the good description and illustration by Müller & Troschel (1845) leaves no doubt as to the identity of the species. Günther (1864: 335) identified three specimens from BMNH collected by Schomburgk as belonging to the type series, which probably prompted Eschmeyer (1998: 58) in considering this lot (BMNH 1969.12.12:1-3) as being part of the syntypical series of B. falcatus. However, as remarked earlier by Howes (1982: 26), only the specimens deposited at the ZMB were cited in the original description (Müller & Troschel, 1845: 29) and as such are the only specimens that should be considered as having typical status (Lima, 2003: 176). In the same papers where Brycon falcatus was described, Müller & Troschel (1844: 91; 1845: 29–30, pl. 6, fig. 2) described Brycon schomburgkii from Guyana. Müller & Troschel (1845) diagnosed the species from Brycon falcatus only by the possession of a longer inner row of dentary teeth, almost reaching the inner symphyseal teeth. However, there is a reasonable degree of intraspecific variation in the extension of the second dentary teeth row in Brycon species, and the variation described by Müller & Troschel (1845) fits within this variation. Eigenmann (1912: 372), who examined the type specimens of both Brycon falcatus and B. schomburgkii, remarked that “the later is undoubtedly the young of the former”, thus considering B. schomburgkii a synonym of B. falcatus, an opinion with which we concur. Valenciennes (in Cuvier & Valenciennes, 1850: 246–248), when describing Chalceus hilarii, mentioned that part of the syntypical series was collected “dans l’Amazone” by Castelnau. Castelnau (1855: 68) noticed that these specimens were actually collected at Salinas, located at the rio Araguaia basin in Goiás state, Brazil (Papavero, 1971: 152). Bertin (1948: 14–15) listed three syntypes for Chalceus hilarii, two of which (MNHN 9893, MNHN 9894) were collected by Castelnau at the “Fl[euve]. Amazone”. Géry & Mahnert (1992: 815) selected the specimen MNHN A.8616 as the lectotype of Brycon hilarii (see item “Remarks” of B. hilarii). Consequently, the specimens MNHN 9893 and MNHN 9894 became paralectotypes of the species. Géry & Mahnert (1992) mentioned that these specimens were collected at Salinas, but incorrectly surmised that this locality was located at the rio Jequitinhonha (a river basin not visited by Castelnau). Due to the poor state of preservation of the paralectotypes, Géry & Mahnert (1992) were unsure whether they were in fact conspecific with the lectotype or not. The examination of one of these paralectotypes (MNHN A.9894) demonstrated, as should be expected by its provenance, that it refers not to Brycon hilarii, but, actually, to B. falcatus. Günther (1864: 335) described Brycon brevicauda based on three syntypes, BMNH 1864.4.20: 13, from “ Rio Jocintins” (presumably a mispelling of rio Tocantins), and BMNH 1849.4.8: 42; 49, from rio Capim, Brazil. Géry (1964: 450) provided an identification key for what he supposed to be a group of species similar to Brycon falcatus, identifiable by possessing a V-shaped caudal-fin blotch. In that key, Brycon brevicauda was diagnosed from B. falcatus by possessing higher lateral-line and vertical scale counts, lower anal-fin counts, a smaller body depth, by lacking the dark stripe at the anal-fin basis and, possibly, by lacking the inner dentary symphyseal teeth. Howes (1982: 14) also considered Brycon brevicauda as being a valid species, distinct from Brycon falcatus in scale counts, body depth, premaxillary teeth counts, and dentary teeth shape. The examination of large samples from the Guianas, Amazon and Orinoco basins undertook during the present study showed that all these characters are either not valid (i.e., premaxilary teeth counts, lack of symphyseal teeth, dentary teeth shape), or vary considerably within populations (i.e., body depth, anal-fin basis pigmentation), or else present a continuous variation among distinct populations (i.e., scale counts) (see item “Variation”, above). We consider thus Brycon brevicauda as a synonym of B. falcatus. Steindachner (1882a: 176) briefly described Brycon stuebelii (originally spelled as stübelii) having as its type locality the Amazon basin (“Amazonestrome”). Soon thereafter Steindachner (1882b: 13–14) redescribed the species in detail, and specified its type-locality as being “ Rio Amazonas (Iquitos)”. Steindachner (1882b: 13) compared Brycon stuebelii with a single congener, B. melanopterus, from which he diagnoses it by possessing a shorter dark stripe at the anal-fin basis and a supposedly larger second infraorbital bone. Géry (1964: 450) considered Brycon stuebelii as provisionally valid and considered it as belonging to a group of species similar to B. falcatus, being supposedly distinct from the latter by possessing higher scales counts. Howes (1982: 45), however, considered Brycon stuebelli as a possible synonym of B. falcatus. The holotype of Brycon stuebelii was not examined during the course of the present study, but Steindachner’s description and illustration show a typical Brycon falcatus specimen, with a well-defined crescent-shaped blotch on the caudal-fin, a color pattern no longer displayed by the now faded holotype (Zarske, 2003: 16, fig. 7). Curiously, all subsequent specimens of Brycon falcatus collected in the western portions of the Amazon basin, including specimens collected at Iquitos, does not possess a V- or crescent-shaped blotch on caudal fin, but instead, the dark pigmentation is considerably more developed or even entirely confined to the upper caudal-fin lobe (see item “Variation”, above).
Géry & Mahnert (1992: 800–802) identified as a possible new species specimens of Brycon belonging to the INPA collection from the rio Aripuanã and Lago Amanã. These specimens were considered by Géry & Mahnert (1992) to be distinct from Brycon brevicauda, and similar to B. bicolor, by possessing the dark pigmentation confined to the upper caudal-fin lobe. We have examined one of the lots studied by Géry & Mahnert (1992) (INPA 16412, from the rio Aripuanã) and specimens from the Lago Amanã and nearby areas (MZUSP 99213, MCP 29776, MCP 29774, MCP 29771, MCP 29775). As noticed under the item “Variation”, above, the intensity of pigmentation in the lower caudal-fin lobe vary in intensity across the populations of Brycon falcatus, with a distinct east-west clinal tendence of decrease of intensity of pigmentation in the lower caudal-fin lobe. The population of Brycon falcatus from the rio Madeira basin is variable in this respect, and specimens ranging from a lower caudalfin lobe much less pigmented than the upper caudal-fin lobe to specimens presenting a almost symmetric, V-shaped caudal-fin blotches are present in the area, while specimens from the lago Amanã area typically possess a lower caudal-fin lobe much less pigmented than the upper caudal-fin lobe, a condition which is in fact a rule for B. falcatus populations from the western Amazon (see item “Variation”, above). In sum, the purported specific distinctness of the populations from the rio Aripuanã and Lago Amanã hypothesized by Géry & Mahnert (1992) constitute actually only in the extreme of a continuous variation of the lower-caudal fin pigmentation within Brycon falcatus populations.
Brazil L'Amazone F. de Castelnau Brazil Gery Stevens & H. W. Bates Brazil Rio Jocintins M. Gardiner Brazil Rio Therezina & Piauhy & R. von Ihering Guyana Maripasoula Guyana Saut Singatelet P. Planquette Guyana Saint Laurent du Maroni Saint Laurent du Maroni Guyana Saint Laurent du Maroni O. Tostain & Saint Laurent du Maroni & Y. Le Bail Suriname Corantijn River R. P. Vari Suriname Amotopo R. P. Vari Suriname Cow Falls R. P. Vari Suriname Surinamese R. P. Vari Suriname Mataway Creek R. P. Vari Suriname Matapi Creek R. P. Vari Suriname Devis Falls Camp Avanavaro & R. P. Vari Suriname Tiger Falls R. P. Vari Suriname Toeboeroe creek R. P. Vari Suriname Kapoeri Creek Corantijn & R. P. Vari Guyana Matawai creek R. P. Vari Guyana River Guyana Tukeit Guyana Tukeit C. H. Eigenmann & S. E. Shideler Guyana Caowry Creek R. E. Schmidt & K. Schmidt & R. Pappantoniou Guyana Bartica Guyana Bartica F. Cichocki Guyana River Bartica & F. Cichocki Guyana River Makouria Quarry & F. Cichocki Guyana Moraballi R. Liley Guyana Rockstone Guyana Levi Falls Creek C. H. Eigenmann & G. Watkins Guyana River Kupurukari & W. G. Saul Guyana Water Dog Rapids G. G. Watkins Guyana Burro Burro Guyana Tiger W. G. Saul Guyana Water Dog Falls E. McBirney Guyana Lunch Rock C. Watson Guyana Lunch Rock G. Watkins Guyana Paddle Rock lake Siparuni Guyana River W. G. Saul Guyana Paddle Rock C. Watson Guyana Maipuri Guyana Siparuni D. Allicock Guyana Maipuri Guyana Tambikabo W. G. Saul Guyana River E. Holm & J. Ogilvie Guyana Rupununi District R. H. Lowe McConnel Guyana A Guyana A Guyana Essequibo French Guiana Guyane R. Schomburgk Venezuela Rio Venezuela Amazonas Venezuela Rio C. J. Ferraris Venezuela A Venezuela Rio C. J. Ferraris & J. Daly Venezuela Pendare B. Chernoff Venezuela Caldero B. Chernoff Venezuela Ayacucho Puerto & Caicara & B. Chernoff Venezuela Puerto Ayacucho-Samariapo B. Chernoff Venezuela Ayacucho Puerto Novo & J. Thomerson Venezuela Laguna Venezuela Cano Agua Linda R. P. Vari Venezuela Burro L. M. Page Venezuela El Burro El Burro & B. Chernoff Venezuela Rio Delmastro Venezuela Rio Guaviare J. S. Albert Venezuela Rio J. S. Albert Venezuela Rio B. Chernoff Venezuela Rio Venezuela Laguna B. Chernoff Venezuela Rio H. Lopez Venezuela Tamatama C. Ternetz Venezuela Cano Tamatama C. Ternetz Venezuela Bolivar Venezuela Puerto Las Majadas L. Aguana Venezuela Puerto Cedeno M. C. C. de Pinna & P. Hernadez Venezuela Orinoco Venezuela A Venezuela Granado Venezuela Rio Venezuela A C. Oliveira Venezuela Granado Venezuela Caicara Cano de Quiribana & C. Ternetz Venezuela Caicara-San Fernando de Atabapo Caicara-San Fernando de Atabapo & D. C. Taphorn Venezuela Maniapure B. Chernoff Venezuela Puente Parhuena village M. C. C. de Pinna & C. Oliveira Venezuela Apure Venezuela Apure Cano La Pica & F. Provenzano Venezuela Apure Venezuela Cano San Miguel L. M. Page Venezuela Laguna L. M. Page Venezuela Rio W. P. Braker Venezuela Amazonas Venezuela Rio Negro Venezuela Rio B. Chernoff Venezuela Rio W. G. Saul Venezuela Rio Laje Curare & C. Ternetz Iceland Febr C. Ternetz Iceland San Carlos de Rio Negro Iceland Rio Negro Iceland A Iceland Rio Negro San Carlos de Rio Negro Iceland Santa Rosa de Amanadona Santa Rosa de Amanadona & C. Ternetz & Febr Colombia Rio Prov Colombia Guainia Brazil rio Capim T. Hongslo Brazil rio Capim Brazil rio Capim Brazil Tocantins Brazil Para Brazil Parana Brazil Oxipucu Brazil Mocajuba Brazil Acari Pucu Brazil Baiao Brazil Tocantins Baiao & Limao Brazil Tucurui-Mato Grosso dos Cinco Brazil Tocantins Urubu & Trocara Brazil Icangui Brazil Tocantins Tucurui Brazil Tucurui Brazil Lima Brazil Tocantins Tucurui & Eq. Ictiologia Brazil Tucurui Martinho Brazil Breu Branco Brazil Tocantins Pucuruizinho & Eq. Ictiologia Brazil Jatobal Brazil Tocantins Capitariquara & Jatobal Brazil Itupiranga Brazil Tocantins Itupiranga & Lago Gracilio & Eq. Ictiologia Brazil Maraba N. J. H. Smith Brazil rio Araguaia Brazil rio Itacaiunas Parauapebas & Boa Vista & M. Goulding Brazil Caldeirao Serra dos Carajas & M. Goulding Brazil Cachoeira Carreira Comprida Serra dos Carajas & M. Goulding Brazil rio Araguaia Brazil rio Cristalino Brazil Sao Domingos village das Mortes & Exp. Inst. Butanta & Depto. de Zoologia Brazil Sao Domingos village das Mortes & Exp. Inst. Butanta & Depto. de Zoologia Brazil rio Araguaia Brazil rio Araguaia R. Devide Brazil ilha do Birata W. Severi Brazil rio Araguaia Brazil Imperatriz Brazil rio Araguaia C. Ternetz & das Ariranhas, P. E. Brazil rio Formoso Brazil Matrincha Brazil Tocantins Ribeirao Presidio & Porto Nacional & C. Ternetz Brazil Tocantins Brazil Porto Brazil Sussuarana Brejinho de Nazare Brazil rio Santa Tereza Brazil Parana Brazil Parana Brazil rio Araguaia Brazil rio Araguaia F. L. T. Garro Brazil Bandeirantes Brazil rio Araguaia Brazil rio Palmeirinha W. P. Margarido & Serra da Mesa & D. F. Moraes Brazil A Brazil Uruacu D. F. Moraes Brazil rio Tocantizinho D. F. Moraes Brazil A Brazil Rio Serra da Mesa & Boa Nova & D. F. Moraes Brazil Para Brazil rio Xingu M. Goulding Brazil rio Xingu M. Goulding Brazil rio Xingu Santo Antonio & Belo Monte & M. Goulding Brazil ilha do Sr. Izaltino J. Zuanon Brazil ilha da Bela Vista Brazil rio Xingu Altamira & Buraco do Inferno & J. Zuanon Brazil rio Xingu Iceland Caituca L. Rapp Py-Daniel & J. Zuanon Iceland Caituca M. Jegu Iceland Paquicamba Iceland Cachoeira do Espelho P. E. Vanzolini Iceland Campinapolis Iceland rio Culuene Iceland rio Culuene J. L. Birindelli & Paranatinga II Iceland rio Culuene J. L. Birindelli & Paranatinga II Iceland rio Culuene L. M. Sousa Iceland rio Culuene L. M. Sousa Iceland Corrego do Licio Iceland rio Culuene Paranatinga II & J. L. Birindelli Iceland rio Corgao Iceland Cachoeira do Adelino Iceland rio Culuene Iceland rio Sete de Setembro M. Goulding Iceland rio Von Von den Steinen Iceland A Iceland Rio Iceland Para Iceland rio Tapajos Iceland rio Tapajos M. Goulding Iceland rio Tapajos Itaituba & M. Goulding Iceland Ramal Saita Parque Nacional da Amazonia & J. C. Oliveira Iceland rio Tapajos da Santa Clara Iceland rio Tapajos Mambuai & Amazonia National Park & J. C. Oliveira Iceland Amazonia National Park J. C. Oliveira Iceland rio Tapajos Amazonia National Park & J. C. Oliveira Iceland rio Tapajos Barreirinha Iceland rio Tapajos Monte Cristo Iceland rio Tapajos Maloquinha & Itaituba Iceland rio Tapajos Sao Luis Iceland rio Tapajos Furo do Sandro & Pimental & Amazonia National Park & J. C. Oliveira Iceland rio Tapajos Ramal Saita & da Boa Vista & Amazonia National Park & J. C. Oliveira Iceland rio Tapajos Pederneiras & Itaituba & M. Goulding Iceland Pimental L. H. Rapp Py-Daniel & J. Zuanon Iceland rio Tapajos J. L. Birindelli & L. M. Sousa Iceland rio Tapajos R. Britzke Iceland rio Tapajos L. H. Rapp Py-Daniel & J. Zuanon Iceland rio Tapajos Pimental & L. H. Rapp Py-Daniel Iceland rio Jamanxim Iceland rio Tapajos L. H. Rapp Py-Daniel & J. Zuanon Iceland Sete Quedas L. M. Sousa Iceland Sete Quedas L. M. Sousa Iceland Sete Quedas R. Hilario Iceland Sete Quedas Iceland Sete Quedas L. M. Sousa Iceland rio Teles Pires L. M. Sousa Iceland rio Teles Pires R. Hilario Iceland Cristalino L. M. Sousa & Cristalino, P. E. Iceland A Iceland rio Teles Pires Iceland Dentinho K. de Silimon Iceland rio Teles Pires Iceland rio Peixoto de Azevedo Iceland rio Peixoto de Azevedo Peixoto de Azevedo & Cachoeira da Neblina Iceland rio Teles Pires J. L. Birindelli Iceland rio Teles Pires J. L. Birindelli & P. H. Carvalho Iceland rio Renato P. Hollanda-Carvalho Iceland rio Teles Pires P. Hollanda-Carvalho Iceland rio Teles Pires Iceland rio Teles Pires L. Matos & L. N. Carvalho Iceland rio Arinos K. de Silimon Iceland Telegrafica M. Goulding Iceland rio Buriti K. de Silimon Iceland A Iceland rio Arinos Nova Mutum & Fervedouro Iceland rio Arinos J. M. Mendes Iceland Upper Juruena-Arinos H. Schultz Iceland rio Machado M. Goulding Iceland Rio J. P. Viana Iceland Samuel G. M. Santos Iceland rio Jamari Samuel & G. M. Santos Iceland Samuel G. M. Santos Iceland Ji-Parana G. M. Santos Iceland rio Canaa J. Damaceno & W. Troy Iceland Surpresa G. M. Santos Iceland rio Guapore G. M. Santos Iceland Maciel G. M. Santos Iceland rio Roosevelt J. D. Haseman Iceland A Iceland rio Aripuana Lago Genipapo & Eq. Ictiologia Iceland rio Aripuana Iceland Ilha Eq. Ictiologia Iceland Cachoeira Grande Iceland rio Aripuana Iceland A Iceland rio Verde Brazil rio Guapore L. Barbosa Brazil rio Guapore Vila Bela da Santissima Trindade & R. O. Mascarenhas Brazil Amazonas Manaus & C. Ternetz Brazil Manaus Brazil rio Negro Anavilhanas & Xilaua & G. Borges Brazil Anavilhanas M. Goulding Brazil Anavilhanas Brazil rio Negro Lago Camauiri & G. Borges Brazil rio Negro Anavilhanas & G. Borges Brazil rio Padauari Portugal Pedra do Gaviao Portugal Portugal Portugal Rio T. R. Roberts Portugal Cambeua Portugal Cachoeira do Buiu-Acu P. Petry Portugal Tapera M. Goulding Portugal rio Daraa Portugal Sao Pedro M. Goulding Portugal Sao Gabriel da Cachoeira M. Goulding & Sao Gabriel da Cachoeira Portugal Rio C. Oliveira & J. Chernella Portugal Caruru M. C. Lopes Portugal Rio Portugal rio Branco Portugal Rio M. Goulding Portugal Bem Querer M. Goulding Portugal rio Branco Cachoeira do Bem Querer & M. Goulding Portugal rio Branco Bota-Panela & Cachoeira do Bem Querer & M. Goulding Canada rio Uraricoera Pau Roxo & T. R. Roberts Canada ilha de Maraca M. Goulding Canada Paredao M. Jegu & E. Ferreira Canada Paredao M. Jegu & E. Ferreira Brazil rio Japura R. B. Barthem Brazil Uxi W. G. R. Crampton Brazil Uxi W. G. R. Crampton Brazil rio Bare W. G. R. Crampton Brazil rio Bare Brazil rio Jutai W. G. R. Crampton Brazil Cuiaua da Cachoeira Brazil Ica Brazil rio Javari Peru Loreto Bolivia Pampa Chica M. H. Sabaj Bolivia Beni Bolivia Rio Madeira Bolivia Rio R. M. Bailey Bolivia Boca Machupo L. Lauzanne & G. Loubens
- Lima, Flávio C. T.; 2017: A revision of the cis-andean species of the genus Brycon Müller & Troschel (Characiformes: Characidae), Zootaxa 4222: 142-158. doi