Brycon vermelha

Lima, Flávio C. T., 2017, A revision of the cis-andean species of the genus Brycon Müller & Troschel (Characiformes: Characidae), Zootaxa 4222 (1), pp. 1-189 : 43-47

Brycon vermelha Lima & Castro, 2000

( Figs. 26–27 )

Brycon vermelha Lima & Castro, 2000: 156–159, figs.1, 2 (sup.) (Type locality: “ Brazil, Minas Gerais, município de Carlos Chagas, rio Mucuri, approximately 9 km W of village of Presidente Pena, along a dirt road on Fazenda Gavião (17°42'S 40°58'W)”); Pompeu & Martinez , 2006: 343, 346 ( Rio Mucuri , Santa Clara ; presence in the Santa Clara power plant’s lift); Pompeu & Martinez , 2007: 172 ( rio Mucuri , downstream Santa Clara reservoir; CPUE); Pompeu & Vieira , 2008: 57–58 (distribution, ecology, conservation); Travenzoli et al., 2015: 6, 8–11, 14 ( rio Mucuri , Carlos Chagas , Minas Gerais; cytogenetics, phylogenetics relationships, molecular taxonomy).

Diagnosis. Brycon vermelha can be diagnosed from all remaining cis-andean Brycon species, with the exception of B. stolzmanni , B. coxeyi , B. coquenani , B. insignis , B. howesi , B. dulcis , B. ferox , 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 vermelha can be diagnosed from these species, with the exception of B. howesi , B. insignis , and B. coquenani , by possessing a fifth infraorbital bone considerably wider than high (vs. fifth infraorbital bone about as wide as high; see Fig. 6 ). Brycon vermelha can be easily distinguished from B. insignis and B. howesi by possessing scarlet-red colored caudal, dorsal, adipose, anal and pelvic-fins in living, clear in preserved specimens (vs. darkened fins, without any red pigmentation in both living and preserved specimens in B. insignis and B. howesi ). Brycon vermelha can be distinguished from B. coquenani (from which the color pattern in life is unknown) by possessing a higher head (70.3–75.5 % of head length, mean 72.3, vs. 59.8–64.9 %, mean 61.4, in B. coquenani ), and by possessing pointed penta- to heptacuspidate dentary teeth, with moderately developed lateral cusps (vs. pointed, tri- to tetracuspidate dentary teeth, with lateral cusps poorly developed). See “Remarks”, below, for further notes on the diagnosis of the species.

Description. Morphometric data are presented in Table 6 . Large-sized species, largest examined specimen 395.0 mm SL. Body moderately high in specimens larger than 370 mm SL, moderately slender in specimens between 200–230 mm SL. Largest body height immediately ahead of dorsal-fin origin. Dorsal body profile slightly convex from upper lip margin to vertical through anterior naris, slightly to moderately convex from latter point to basis of supraoccipital process, and moderately convex from latter point to dorsal-fin origin, straight along dorsalfin basis, 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 conspicuously acute anteriorly, mouth terminal. Premaxillary and dentary isognathous, i.e., approximatelly of same size. Maxillary long, extending posteriorly to slightly posterior to middle of pupil. Adipose eyelid well developed. Premaxillary teeth in three rows; teeth of third row largest. Eight (1), 9 (3), 10 (1), 11 (3), 12 (1), or 13 (1) tricuspidate teeth, with poorly developed lateral cusps, in outer series. Four (1), 5 (7), or 6 (2) tricuspidate teeth in second, inner premaxillary row, plus 2 (9) or 3 (1) tri- to tetracuspidate 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. Twenty to 29 maxillary teeth, slightly smaller than teeth of first premaxillary row, anterior teeth tricuspidate, posterior teeth unicuspidate. Dentary with 10 (1), 11 (1), 13 (3), 14 (3), 15 (1), or 16 (1) teeth in main series. Anterior four dentary teeth assymetrical, considerably larger and bulkier than remaining teeth, hexa- to heptacuspidate, each with central cusp distinctly larger than remaining cusps. Remaining dentary teeth progressivelly smaller, 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 a row of six to eleven small, unicuspidate teeth in the posterior portion of the dentary. Inner symphyseal teeth present in three out of nine specimens (MZUSP 58049, 229.5 mm SL; LBP 9066, 213.0 mm SL) examined for this character.

Scales cycloid. Lateral line complete, from supracleithrum to caudal-fin base. Forty-seven (1), 51 (2), 52 (4), 53 (2), or 54 (1) scales in lateral line series. Laterosensory tube simple in middle-sized (200–230 mm SL) specimens, deflected upwards in the first 5–6 scales, downwards in the remaining lateral-line scales. Larger specimens (> 370 mm SL) with branched tubules, mostly bifurcated but some scales with 3 or 4 tubules. Horizontal scale rows between dorsal-fin origin and lateral line 10 (5), 11 (3), or 12 (2). Horizontal scale rows between lateral line and pelvic-fin 4 (3), 5 (4), or 6 (3). Circumpeduncular scales 17 (1), 18 (1), 19 (6), or 20 (1).

Dorsal-fin rays ii, 9. Dorsal fin origin at, or slightly ahead of, middle of SL. Anal-fin rays iii (not including first, small unbranched ray only visible in the cs specimen), 21 (1), 22 (3), 23 (3), or 24 (3). Last unbranched and anterior 3–4 branched anal-fin rays longer, remaining rays progressively shorter towards anal-fin end. Sheath of scales covering basis of anal-fin rays composed of three scale rows, lower scale row formed by 25–30 rectangular scales. Pectoral-fin rays i, 12 (1), 13 (7), or 14 (2). Pelvic-fin rays i,7. Main caudal-fin rays 10/9. Caudal fin forked, lobes slightly pointed.

First branchial arch with 8 (1), 10 (2), or 11 (1) lower, 1 at angle, and 8 (2) or 9 (2) upper gill rakers.

Coloration in alcohol. Top of head, snout, supraorbital, sixth infraorbital, upper portion of fifth infraorbital, and dorsal portion of body dark- to chestnut-brown. Second, third, fourth and lower portion of fifth infraorbitals silvery hue. Opercle mainly silvery, with some light-brown tinge in specimens which retained relatively less guanine. Dentary, maxillary, gular area and lower portion of body brownish. Lateral portion of body silvery in specimens retaining a considerable amount of guanine, light brown in specimens that lost most guanine (e.g., MZUSP 56048). Humeral blotch present, very little conspicuous, approximately rounded in shape, situated immediately above lateral line, its anterior margin at level of second, extending longitudinally to posterior margin of fourth lateral line scales, and vertically less than one scales high. Large, conspicuous, oval-shaped caudal peduncle blotch, extending along 7–8 last lateral-line scales. Dorsal, anal, and caudal-fins brownish, with scattered dark pigmentantion on interradial membranes. Pectoral, pelvic and adipose-fins light brown.

Coloration in life. Based on pictures of an unpreserved specimen, collected at the rio Mucuri nearby Carlos Chagas, plus color transparencies of the type series. Overall body color silvery. Snout and top of head dark grey. Dorsum, fifth and sixth infraorbital bones plumbeous. Dentary, gular and ventral areas clear. Series of red spots on four to five lateral scales rows situated below lateral line, extending to scales situated at the level of anal-fin origin. Rounded caudal peduncle blotch dark, very conspicuous. Adipose, anal and caudal-fin scarlet-red. Distal margin of dorsal fin scarlet red. Pelvic fins reddish. Pectoral fins hyaline.

Sexual dimorphism. Not observed. Hooks were not found in any examined specimen, including the two male paratypes (MZUSP 53304 and USNM 320481), which are in an obvious breeding condition, with fully mature testicles.

Common names. “ Vermelha ” ( Lima & Castro, 2000: 159).

Distribution. Known from the middle and upper portions of the rio Mucuri basin, a coastal river system draining northern Minas Gerais and southern Bahia states, Brazil ( Fig. 25 ). The species is apparently absent from the lower portion of this river system ( Pompeu & Vieira, 2008). Fishermen from Carlos Chagas report the occurrence of the species at the rio São Mateus, an independent small coastal system, situated immediately south to the rio Mucuri at the Espírito Santo state, but its occurrence at this basin was so far not confirmed (L.F.S. Ingenito & L.F. Duboc, pers. comm.).

Ecological notes. All type specimens were collected at a river stretch within a forest remnant. Fishermen of the rio Mucuri report that, in fact, Brycon vermelha favor areas with preserved riparian forest. Stomach contents of the the paratypes included a loricariid catfish, a Rhamdia sp. of about 95 mm SL, and unidentified fruit remains ( Lima & Castro, 2000: 161). Both paratypes were males, with fully mature testicles, and were evidently in breeding condition. The species is more common in the middle and lower stretches of the rio Mucuri, where it represents 2 % of the specimens captured in experimental fishing ( Pompeu & Vieira, 2008). In contrast, at the area of Santa Clara hydroelectric dam, at the divide between Minas Gerais and Bahia states and at the transition between the middle and lower rio Mucuri, out of 45.000 fish specimens that bypassed the fish ladder during the fish migration season at 2003/2004, only two were Brycon vermelha ( Pompeu & Vieira, 2008) . Brycon vermelha occurs syntopically with the congener B. ferox (see “Ecological notes” of this species).

Conservation. Brycon vermelha is officially considered threatened with extinction in Brazil ( Pompeu & Vieira, 2008). Causes for concern are the limited natural distribution of the species, restricted to a single small hydrographic basin in eastern Brazil, coupled with its preference for river stretches with preserved forest remnants in an area which is now mostly reduced to pastureland. Additionally, a small hydroelectric dam, the Mucuri dam, was build right at the core area of occurrence of the species in the upper rio Mucuri near Carlos Chagas. There is no recent information as to the conservation status of Brycon vermelha after the completion of this dam but with all likelihood the species has become even more imperiled than was before this event.

Remarks. The scarlet-red fin coloration displayed by Brycon vermelha is a unique feature that promptly diagnoses the species from all remaining Brycon species occurring in the coastal river drainages of eastern Brazil. Among the Brycon species occurring in the coastal river drainages from eastern Brazil possessing an acute head profile, Brycon vermelha is more similar to B. insignis and B. howesi . Brycon vermelha is very similar to B. insignis , and there are apparently no unambiguous features that allow their diagnosis other than the fin color. Brycon vermelha , however, possess more volumous dentaries and premaxillaries than B. insignis , which results in a more rounded snout and mandible profile than in the former. Also, dentary and premaxillaries are about the same size in Brycon vermelha , while in most individuals of B. insignis the premaxilla extends a little beyond the dentary, i.e., the jaws are anisognathous. Body color pattern in Brycon vermelha differ at least from the wild-caught B. insignis examined by lacking the striped and reticulated dark pigmentation patterns present in the latter, as well as for displaying a humeral blotch much less conspicuous than the one displayed by B. insignis . Gill raker counts also seem to differ between both species: Brycon vermelha possess 8–11 lower, and 8–9 upper gill rakers, vs. 11–16 lower, and 11–17 upper gill rakers in B. insignis . For a comparison between Brycon vermelha and B. howesi , see item “Diagnosis” of the latter species.

Though Brycon vermelha was only recently described, a specimen of the species was already collected by Charles Hartt and Edward Copeland during the Thayer Expedition, between 1865–1866 ( MCZ 162613 ). This specimen was collected in the rio Mucuri at Santa Clara , a portion of this river where the species is now thought to be naturally scarce (see “Ecological notes”, above). Interestingly , Steindachner, who studied in detail material collected by the Thayer Expedition in eastern brazilian rivers, and described some of the Brycon species from eastern Brazil based on it ( Steindachner, 1877), did not noticed this particular specimen.

Material examined. Type material: MZUSP 53303 (1, 395.0 mm SL), Brazil, Minas Gerais, Carlos Chagas, rio Mucuri , rio Mucuri , approximately 9 km W of village of Presidente Pena , along a dirt road on Fazenda Gavião , c. 17°37’S, 40°55’W; R.M.C. Castro & S.L. Jewett, 17–23 July 1991 . Holotype of Brycon vermelha . MZUSP 53304 (1, 372.0 mm SL); USNM 320481 (1, 379.5 mm SL), same data as holotype; paratypes .

Non types. Brazil, Minas Gerais: UFMG uncataloged (1, 223.5 mm SL), Carlos Chagas, rio Mucuri ; V.

Vono, no date. MZUSP 58049 (1, 229.5 mm SL), Carlos Chagas, rio Mucuri ; V. Vono, 14 Jan 1997 . MZUSP 70217 (2, 215.3– 233.6 mm SL), Carlos Chagas, rio Mucuri, above Presidente Pena village ; F. Vieira, April 2001. LBP 9066 (2, 213.0–255.0 mm SL): Minas Gerais, rio Mucuri , c. 17°41’S, 40°46’W; J . A. Senhorini, 6 Feb 2010 . Bahia: MCZ 162613 (1, 203.0 mm SL): Santa Clara, rio Mucury [Rio Mucuri at Santa Clara ], c. 17°54’S, 40°13’W; C.F. Hartt & E. Copeland, Dec 1865 – April 1866.

Figures

FIGURE 5. Diagrammatic representation of the patterns of dark colour markings found among cis-andean Brycon species, represented by selected species. A. Brycon stolzmanni. B. Brycon coxeyi. C. Brycon insignis. D. Brycon nattereri. E. Brycon hilarii. F. Brycon whitei. G. Brycon amazonicus. H. Brycon gouldingi. I. Brycon melanopterus. J-L. Brycon falcatus.

FIGURE 6. Diagrammatic representation of the head profile, maxillary and infraorbitals showing the distinct morphologies found among cis-andean Brycon species, represented by selected species. A. Brycon amazonicus, MZUSP 3815, 152.3 mm SL. B. Brycon insignis, MCZ 21112, 232.2 mm SL. C. Brycon dulcis, MZUSP 1531, 146.6 mm SL. D. Brycon falcatus, MZUSP 3845, 195.1 mm SL. E. Brycon opalinus, MCZ 21123, 210.5 mm SL. F. Brycon orbignyanus, MZUSP 3900, 108.9 mm HL. G. Brycon ferox, MCZ 60934, 310.3 mm SL. H. Brycon orthotaenia, MZUSP 2007, 188.7 mm SL. I. Brycon polylepis, MZUSP 70413, 203.9 mm SL. J. Brycon stolzmanni, UMMZ 185306, 120.0 mm SL.

FIGURE 25. Map of eastern Brazil, showing known localities of Brycon insignis (red dots), B. vermelha (grey dots), and B. howesi (black dots; dark star indicates type-locality).

FIGURE 26. Brycon vermelha, holotype, MZUSP 53303, 395.0 mm SL: Brazil, Minas Gerais, rio Mucuri.

FIGURE 27. Brycon vermelha, MZUSP 70217, 215.3 mm SL: Brazil, Minas Gerais, rio Mucuri.

Tables

TABLE 6. Morphometric data of Brycon vermelha (A: holotype, MZUSP 53303).

	A	n	Range	Mean
Standard length (SL)	395.0	10	203.0–395.0	-
Percentages of standard length
Depth at dorsal-fin origin	37.5	9	26.9–37.5	30.6
Snout to dorsal-fin origin	54.2	10	50.7–59.6	52.9
Dorsal-fin base length	13.1	10	11.4–13.4	12.3
Posterior terminus of dorsal fin to adipose fin	20.8	10	19.9–24.0	22.0
Posterior terminus of dorsal fin to hypural joint	37.0	10	30.7–38.9	35.4
Snout to pelvic-fin insertion	47.7	9	46.3–50.1	48.3
Snout to anal-fin origin	64.6	10	64.5–69.1	66.8
Anal-fin base length	22.8	10	20.1–24.5	22.3
Caudal peduncle length	15.2	10	10.0–16.2	14.2
Dorsal-fin height	19.2	8	17.1–20.4	19.2
Pectoral-fin length	18.4	9	11.4–19.2	17.3
Pelvic-fin length	18.4	9	13.7–18.4	15.2
Caudal peduncle depth	10.9	10	8.1–10.9	9.7
Head length	28.3	10	24.7–29.4	27.9
Percentages of head length
Head height	72.2	10	70.3–78.6	73.3
Snout length	32.2	10	26.6–33.4	30.6
Upper jaw length	50.4	10	49.4–52.4	50.9
Horizontal eye diameter	15.1	10	15.1–22.3	19.0
Post-orbital length	55.3	10	49.2–55.8	53.9
Least interorbital width	38.0	10	31.3–38.0	33.7