Brycon ferox Steindachner 1877
Creators: name: Lima, Flávio C. T.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Characiformes
Bryconidae
Brycon
Brycon ferox

description: Brycon ferox Steindachner, 1877
(Figs. 33–35)
Brycon ferox Steindachner, 1877: 583 –585, pl. 4, figs. 2, 2a (not 1, 1a) (Type locality: “Rio Mucuri”); Steindachner, 1879c: 50 (correction of the plate caption); Howes, 1982: 28 (taxonomical remarks); Lima & Castro, 2000: 157, 161, fig. 2 (lower) (Brazil, Minas Gerais, Carlos Chagas, rio Mucuri aproximatelly 9 km W from Presidente Pena village, dirt road at fazenda Gavião, 17°42'S, 40°58'W; diet); Pompeu & Martinez, 2006: 343, 345, 347 (Rio Mucuri, Santa Clara; presence in the Santa Clara power plant’s lift); Pompeu & Martinez, 2007: 171, 172, 175 (rio Mucuri, downstream Santa Clara reservoir; CPUE); Menezes et al., 2007: 109 (photograph; distribution, ecology, conservation status); Travenzoli et al., 2015: 6, 8– 11, 14 (rio Mucuri, Carlos Chagas, Minas Gerais; cytogenetics, phylogenetics relationships, molecular taxonomy).
Diagnosis. Brycon ferox can be diagnosed from all remaining cis-andean Brycon species, with the exception of B. stolzmanni, B. coxeyi, B. coquenani, B. vermelha, B. insignis, B. howesi, B. dulcis, B. vonoi, B. opalinus, and B. nattereri by possessing a color pattern consisting in a humeral blotch and a caudal peduncle blotch, without body stripes or other obvious color markings on caudal and anal-fins (vs. body stripes and caudal/anal fin color markings present; see Fig. 5). Brycon ferox can be distinguished from Brycon stolzmanni, B. coxeyi, B. vonoi, B. opalinus, and B. nattereri by possessing a distinctly acute head profile (vs. a roughly rounded to slightly acute head profile). Brycon ferox can be additionally distinguished from B. stolzmanni, and B. coxeyi by the absence of a patch of dark pigmentation on the opercle (vs. dark patch of pigmentation present on opercle). Brycon ferox can be distinguished from B. insignis, B. howesi, B. coquenani, and B. vermelha by possessing by possessing a fifth infraorbital bone about as wide as high (vs. fifth infraorbital bone wider than high; see Fig. 6). Brycon ferox can be distinguished from B. dulcis by presenting a distinctly anisognathous mouth, with a pointed premaxillary, extending beyond dentary, leaving the outer, and often also the second, series of premaxillary teeth exposed in ventral view (vs. premaxillary and dentary approximately isognathous, i.e., of about the same size, leaving only part of outer premaxillary series exposed in ventral view in some specimens). See the item “Remarks” of Brycon vonoi, for additional notes on the recognition of the species.
Description. Morphometric data are presented in Table 10. Large-sized species, largest examined specimen 375.0 mm SL. Body moderately slender in specimens up to 255 mm SL, moderately high in specimens> 310 mm SL. Largest body height slightly ahead of dorsal-fin origin. Dorsal body profile slightly convex from upper lip margin to vertical through anterior naris, slightly concave to straight from latter point to basis of supraoccipital process, moderately 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 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 moderately acute anteriorly, considerably acute in specimens <100 mm SL (MZUSP 70219, 105.2 mm SL; MZUSP 93920, 2, 32.2–38.5 mm SL), mouth terminal. Jaws anisognathous, premaxillary moderately to pronouncedly projected relative to dentary, leaving outer row, and, in large specimens (e.g., MCZ 60934, 310.3 mm SL), also the second row of premaxillary teeth exposed in ventral view when mouth is closed. Maxillary long, extending posteriorly to middle of pupil. Adipose eyelid well developed. Premaxillary teeth in three rows; teeth of third row largest. Six (1), 7 (5), 8 (6), 9 (11), 10 (10), or 11 (1) tricuspidate teeth in outer series. Two (1), 3 (2), 4 (11), 5 (16), 6 (2), or 7 (3) tetra- to hexacuspidate teeth in second, inner premaxillary row, plus 2 (14), 3 (19), or 4 (1) 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 with distal portion distinctly expanded and rounded in profile. Seventeen to 31 maxillary teeth, slightly smaller than teeth of first premaxillary row, anterior teeth tricuspidate, posterior teeth unicuspidate. Dentary with 9 (1), 10 (4), 11 (6), 12 (7), 13 (4), 14 (6), or 15 (1) teeth in main series. Anterior four dentary teeth assymetrical, considerably larger and bulkier than remaining teeth, penta- to heptacuspidate, each with central cusp distinctly larger than remaining cusps. Remaining dentary teeth progressivelly smaller, penta-, tetra-, tri- 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 8 (1), 14 (1), 17 (1), or 28 (1) small, unicuspidate teeth, originating on lingual crest of dentary replacement trench at the level of sixth to ninth main series dentary teeth. Inner symphyseal teeth present in all specimens with relatively intact symphyseal dentary area. Central cusp distinctly larger and pointed, and teeth presenting diastemas in specimens <100 mm SL.
Scales cycloid. Lateral line complete, from supracleithrum to caudal-fin base. Forty-eight (1), 49 (2), 51 (3), 52 (3), 53 (1), 54 (8), 55 (6), 56 (2), 57 (5), 58 (1), 60 (1), or 63 (1) scales in lateral line series. Laterosensory tube simple in small (<180 mm SL) specimens, deflected upwards in the first 5–6 scales, downwards in the remaining lateral-line scales. Larger specimens (> 190 mm SL) with branched tubules, mostly bifurcated but some scales with 3 tubules. Horizontal scale rows between dorsal-fin origin and lateral line eight (1), 9 (10), 10 (21), or 11 (2). Horizontal scale rows between lateral line and pelvic-fin 4 (8), 5 (22), or 6 (4). Circumpeduncular scales 15 (1), 16 (1), 17 (3), 18 (13), 19 (12), 20 (3), or 21 (1).
Dorsal-fin rays ii, 9, a single specimen ii, 8. Dorsal fin origin slightly ahead of middle of SL. First dorsal-fin pterygiophore inserting behind neural spine of 13th (1) vertebra. Anal-fin rays iii (not including first, small unbranched ray only visible in the cs specimen), 22 (1), 23 (2), 24 (7), 25 (9), 26 (10), or 27 (5). First anal-fin pterygiophore inserting behind haemal spine of 23th (1) vertebra. Last unbranched and anterior 4–5 branched analfin rays longer, remaining rays progressively shorter towards anal-fin end. Anal fin displaying numerous (c. 25–30 per fin-ray main branch) middle-sized hooks on last unbranched and posterior main branch of branched rays 14–24, associated with dense, gelatinous tissue in 5 specimens (MZUSP 58048, 240.5 mm SL; MZUSP 70216, 185.3 mm SL; MNRJ 18379, 208.8 mm SL; NMW 62930, 1, 245.0 mm SL; NMW 62937, 1, 265.0 mm SL). A single hook per ray segment. Sheath of scales covering basis of anal-fin rays composed of two scale rows, lower scale row formed by 17–20 rectangular scales. Pectoral-fin rays i, 11 (1), 12 (4), 13 (19), or 14 (10). Pelvic-fin rays i, 7, a single specimen i, 6. Main caudal-fin rays 10/9. Caudal fin forked, lobes pointed.
Four branchiostegal rays, three on anterior ceratohyal and one on posterior ceratohyal. First branchial arch with 9 (1), 12 (4), 13 (5), 14 (5), or 15 (1) lower, 1 at angle, and 8 (1), 11 (3), 12 (6), 13 (4), or 14 (2) upper gill rakers. Vertebrae 44 (1). Supraneurals 10 (1).
Coloration in alcohol. Overall body coloration clear. Top of head, snout, supraorbital, sixth infraorbital, upper portion of fifth infraorbital, and dorsal portion of body light-brown. Second, third, and fourth infraorbitals, and opercle silvery. Dentary, maxillary, gular area and lower portion of body light brown. Lateral portion of body cream-colored, with a silvery hue. Humeral blotch present, generally little conspicuous, approximately rounded in shape, situated immediately above lateral line, its anterior margin at level of second to third, extending longitudinally to posterior margin of fourth to fifth lateral line scales, and vertically less than one scale high. Large, little to moderately conspicuous, oval-shaped caudal peduncle blotch, extending along 8–10 last lateral-line scales. All rayed fins with some amount of dark pigmentation at the interradial membranes, imparting an overall darkened coloration to these fins. Caudal-fin with a poorly discernible, roughly V-shaped blotch, formed by dark pigmentantion situated on outer caudal-fin rays. Adipose fin light-grey to light-brown.
Color in life. Description based on the picture of a freshly collected (LIRP 1311, 310.0 mm SL; Lima & Castro, 2000: 157, fig. 2, lower specimen) and in a picture of a unpreserved specimen from the rio Mucuri (Silva, 1999: 16–17). Infraorbital bones, opercle and sides of body silvery. Opercle with some golden hue. Top of head, snout and dorsum dark-colored. Relatively conspicuous dark humeral and caudal peduncle blotches. Darkened dorsal, caudal, anal and pectoral fins. Specimen LIRP 1311 with series of pinkish spots situated along the four horizontal scale rows situated below scale row immediately below lateral line and anterior to insertion of pelvic fins. Specimens MZUSP 70215 (2, 184.4– 229.4 mm SL) also displayed these pinkish spots when freshly preserved, in 2001.
Sexual dimorphism. Steindachner (1877: 25–26) remarked that two of the syntypes were males and possessed small “denticles” (= “Zähnchen”) in the anal fin. We examined these two syntypes (NMW 62930, 1, 245.0 mm SL; NMW 62937, 1, 265.0 mm SL), plus eight specimens displaying anal-fin hooks (MZUSP 58048, 240.5 mm SL; MZUSP 70216, 185.3 mm SL; MNRJ 18379, 208.8 mm SL; CAS 13206, 5, 227.0–258.0 mm SL). Specimens MZUSP 58048, MZUSP 70216, and MNRJ 18379 were dissected and are males, with moderately well-developed testicles. Four specimens that did not displayed anal-fin hooks (MZUSP 70215, 182.8 mm SL; MZUSP 70216, 196.6– 214.4 mm SL; MNRJ 18379, 255.6 mm SL) proved to be females, with moderately well-developed ovaries.
Common names. “ Piabanha ” (Lima & Castro, 2000: 159).
Distribution. Known from coastal river drainages from northern Espírito Santo (rio Itaúnas) northward to southern Bahia (rio dos Frades drainage), including the rio Mucuri, rio Jucuruçu, and rio Itanhém drainages in the states of Bahia and Minas Gerais, eastern Brazil (Fig. 32).
Ecological notes. Lima & Castro (2000: 161) remarked on the syntopy between Brycon ferox and Brycon vermelha at the middle rio Mucuri, Minas Gerais. However, intensive fish collecting at the rio Mucuri basin demonstrated that Brycon ferox is actually more common at the middle and lower stretches of that river system, being replaced by B. vermelha on the upper stretches (P. Pompeu and F. Vieira, pers. comm.). Brycon ferox is even reported for the lower stretch of the rio Mucuri, near the estuary (Lopes, 2000, F. Vieira and P. Pompeu, pers. comm.). Lima & Castro (2000: 161) found a whole Bolomys lasiurus (Rodentia, Cricetidae) in the stomach of Brycon ferox (LIRP 1311, 310.0 mm SL). The species obviously undertakes a spawning migration, as indicated by the great number of individuals moving upstream during the rainy season (November to March) (Pompeu & Martinez, 2006).
Conservation. Contrary to most Brycon species occurring at eastern Brazil, Brycon ferox currently does not appear to be endangered. The species was still quite common at the middle and lower rio Mucuri during the early 2000’s (F. Vieira and P. Pompeu, pers. comm.), although populations of the species were probably adversely impacted after the building of the Santa Clara dam in 2002 and of the Mucuri dam in 2013. Aparently the species does not depend on riparian forests, since it is relatively common in deforested river stretches (F. Vieira and P. Pompeu, pers. comm.). The species was recently recorded for several small coastal river systems: the rio dos Frades, rio Itanhém, and rio Jucuruçu in southern Bahia and at the rio Itaúnas at northern Espírito Santo. These river systems possess watersheds almost entirely deforested, and the occurrence of Brycon ferox at those rivers apparently indicates some tolerance with this type of anthropogenic impact. However, small hydroelectric dams are being built in some of these rivers (e.g., at the rio Jucuruçu), and Brycon ferox populations will probably be adversely impacted.
Remarks. Steindachner (1877) described Brycon ferox from an unspecified locality at the rio Mucuri, eastern Brazil. The type material was evidently collected by the Thayer Expedition, since almost all material from eastern Brazil studied by Steindachner was brought by him from the MCZ (Steindachner, 1875: 499–500). As discussed under the item “Remarks” of Brycon insignis, we prefer not to consider specimens from MCZ as possessing type status except when Steindachner explicitly mention material deposited in that collection, which does not happen to be the case with B. ferox. There are three syntypes of Brycon ferox deposited at the NMW, the better preserved one (NMW 62930, 1, 245.0 mm SL) being here designated as the lectotype of the species, the two remaining specimens (NMW 62937, 247.0–265.0 mm SL) becoming, thus, paralectotypes.
Interestingly, Howes (1982: 28) suggested that Brycon acuminatus (= B. insignis) might be a synonym of B. ferox. That supposition was based on the examination of the illustration of Brycon ferox by Steindachner (1877). Since the illustration indicated as being Brycon ferox in Steindachner (1877) actually represents B. insignis (Steindachner, 1879c: 50, footnote), Howes (1982) was actually suggesting that B. acuminatus was probably a synonym of B. insignis, an assumption that was proved to be true in the present study (see section “Remarks” of Brycon insignis, above).
Material examined. Type material: NMW 62930 (1, 245.0 mm SL): “ Rio Mucuri” “ I. 1874 ” [rio Mucuri basin, eastern Brazil; collected by C.F. Hartt and E. Copeland, 1865–1866; cf. Dick, 1977, Higuchi, 1996]. Lectotype (by present designation) of Brycon ferox. NMW 62937 (2, 247.0–265.0 mm SL): same data as lectotype; paralectotypes.
Non types. Brazil, Minas Gerais: MZUSP 53305 (1, 210.4 mm SL); USNM 320346 (1, 203.7 mm SL); LIRP 1311 (1, 310.0 mm SL); Carlos Chagas, rio Mucuri, approx. 9 km W of Presidente Pena village, dirt road on Fazenda Gavião, c. 17°37'S, 40°55'W; R.M.C. Castro & S.L. Jewett, 17–23 Jul 1991. MZUSP 58048 (1, 240.5 mm SL), Carlos Chagas, rio Mucuri at Carlos Chagas, c. 17°41’S, 40°46’W; V. Vono, 14 Jan 1997. LBP 9065 (4, 133.9–235.0); LBP 10181 (5, 78.4–88.1 mm SL); LBP 9067 (4, 298.0–375.0 mm SL): Carlos Chagas, rio Mucuri, c. 17°41’S, 40°46’ W; J. A. Senhorini, 6 Feb 2010. LBP 8099 (2, 223.0–268.0 mm SL); LBP 8100 (2, 92.9–97.4 mm SL): Carlos Chagas, rio Mucuri, 17°41’42’’S, 40°46’ 11’’W; C. Oliveira et al., 18 May 2009. MZUSP 70215 (8, 182.8– 238.8 mm SL), Nanuque, rio Mucuri, downstream Tombo, c. 17°51’S, 40°18’W; F. Vieira, April 2001. Bahia: MCZ 60934 (1, 310.3 mm SL); MCZ 21108 (1, 375.0 mm SL); MCZ 21107 (3, 197.4– 202.3 mm SL): CAS 13206 (5, 227.0–258.0 mm SL): rio Mucuri at Santa Clara; 17°54'S, 40°13'W; C.F. Hartt & E. Copeland, Dec 1865 — April 1866. USNM 301696 (1, 264.6 mm SL), rio Mucuri drainage, rio Mucuri approx. 26 km SE of town of Nanuque on Fazenda Santa Clara, 17°54'S, 40°13'W; S.L. Jewett & R.M.C. Castro, et al., 4–5 Aug 1988. MZUSP 70216 (4, 185.3– 214.4 mm SL), Argolo, rio Mucuri, c. 17°56’S, 40°7’W; F. Vieira, April 2001. MZUSP 70219 (1, 105.2 mm SL), Mucuri, rio Mucuri, near its mouth, c. 18°5’S, 39°34’W; F. Vieira & P.S. Pompeu, Jan 2001. UFBA 5095 (2 of 5, 83.6–107.0 mm SL): Itamaraju, rio Jucuruçu (= Braço Sul), road BR-101, 17°14’52’’S, 39°37’15’’W; A.M. Zanata et al., 28 Feb 2009. UFBA 5060 (1, 128.1 mm SL): Teixeira de Freitas, rio Itanhém, Prainha village, near road BR-101, 17°30’9’’S, 39°41’59’’W; A.M. Zanata et al., 28 Feb 2009. MZUSP 93920 (2, 32.2–38.5 mm SL): Trancoso, rio dos Frades, 16°38’39’’S, 39°8’32’’W; N. A. Menezes, O.T. Oyakawa, J.C. Nolasco & L.M. Sousa, 1 April 2006. Espírito Santo: MNRJ 18379 (3, 192.3– 255.6 mm SL), Pedro Canário, rio Itaúnas, Fazenda Boa Lembrança, c. 18°19’S, 39°50’W; A.C. Aguirre, 1950. UFBA 5021 (2 of 3, 87.4–115.6 mm SL): Pedro Canário, rio da Samambaia (trib. rio Itaúnas), road BR-101, 18°12’24’’S, 39°55’56’’W; A.M. Zanata et al., 27 Feb 2009.
description: Published as part of Lima, Flávio C. T., 2017, A revision of the cis-andean species of the genus Brycon Müller & Troschel (Characiformes: Characidae), pp. 1-189 in Zootaxa 4222 (1) on pages 58-62, DOI: 10.5281/zenodo.257769