A revision of the cis-andean species of the genus Brycon Müller & Troschel (Characiformes: Characidae)
Author
Lima, Flávio C. T.
text
Zootaxa
2017
4222
1
1
189
journal article
37268
10.5281/zenodo.257769
9ea59a17-588e-4af1-8c0d-ebcd50ad0395
1175-5326
257769
F0EC0A87-B1EE-4B5C-8F53-77A7EEA75F3A
Brycon stolzmanni
Steindachner, 1879
(
Figs. 7–9
)
Brycon stolzmanni
Steindachner, 1879a
: 152
(Type locality, “Chota”; brief description);
Steindachner, 1879b
: 170
, pl. 2, figs.6, 6a (full description);
Pearson, 1937
: 90
(Peru: Balsas; Paipay, Rio Crisnejas; Tingo de Pauca, Rio Marañon; Pusoc, above Balsas).
Diagnosis.
Brycon stolzmanni
can be distinguished from all remaining cis-andean
Brycon
species, except
B. coxeyi
, by possessing a distinct patch of dark pigmentation on the opercle (vs. patch of dark pigmentation on the opercle absent in the remaining cis-andean
Brycon
species) and infraorbital series not closed, with the orbital margin partially delimited by the frontal bone (vs. infraorbital series closed, frontal excluded from the orbital series by the contact between the supraorbital and the sixth infraorbital bone).
Brycon stolzmanni
can be distinguished from
B. coxeyi
by possessing the dark patch of pigmentation on the opercle diffuse and covering the upper half of the bone (vs. dark patch of pigmentation on opercle very conspicuous and typically lying at its center).
Description.
Morphometric data are presented in
Table 1
. Relatively small-sized species, largest examined specimen 214.0 mm SL. Body moderately high. Largest body height at dorsal-fin level. Dorsal body profile slightly convex from upper lip margin to vertical through anterior naris, slightly concave to slightly convex from latter point to basis of supraoccipital process, and moderately convex from latter point to dorsal-fin origin, straight along dorsal-fin basis, straight to slightly convex from dorsal-fin terminus to adipose-fin origin. Dorsal profile of caudal peduncle slightly concave. Ventral profile slightly convex from lower lip to pelvic-fin insertion, slightly convex to straight from this point to anal-fin origin and approximately straight along anal-fin base. Ventral profile of caudal peduncle slightly concave.
TABLE 1.
Morphometric data of
Brycon stolzmanni
(A: lectotype, NMW 62731).
A |
n |
Range |
Mean |
Standard length (SL) |
124.5 |
36 |
66.6–185.5 |
- |
Percentages of standard length |
Depth at dorsal-fin origin |
33.0 |
36 |
29.9–34.0 |
31.8 |
Snout to dorsal-fin origin |
52.0 |
36 |
48.5–53.4 |
51.0 |
Dorsal-fin base length |
12.4 |
36 |
10.6–14.9 |
12.6 |
Posterior terminus of dorsal fin to adipose fin |
21.8 |
36 |
21.1–26.6 |
23.6 |
Posterior terminus of dorsal fin to hypural joint |
39.0 |
36 |
35.5–42.9 |
39.0 |
Snout to pelvic-fin insertion |
52.0 |
34 |
47.9–53.3 |
49.9 |
Snout to anal-fin origin |
69.4 |
36 |
63.3–69.4 |
66.0 |
Anal-fin base length |
22.5 |
35 |
19.4–23.9 |
22.0 |
Caudal peduncle length |
13.5 |
36 |
13.5–18.8 |
17.1 |
Dorsal-fin height |
22.2 |
36 |
16.2–25.1 |
20.9 |
Pectoral-fin length |
20.3 |
36 |
18.4–22.7 |
20.1 |
Pelvic-fin length |
14.9 |
36 |
13.6–17.6 |
15.2 |
Caudal peduncle depth |
11.5 |
36 |
10.2–12.1 |
11.4 |
Head length |
29.4 |
36 |
26.2–31.1 |
27.8 |
Percentages of head length |
Head height |
79.8 |
36 |
76.7–90.8 |
82.8 |
Snout length |
26.0 |
36 |
23.0–30.1 |
26.8 |
Upper jaw length |
42.9 |
35 |
40.4–45.3 |
43.2 |
Horizontal eye diameter |
21.3 |
36 |
21.3–28.9 |
24.0 |
Post-orbital length |
52.5 |
36 |
49.0–56.3 |
52.6 |
Least interorbital width |
32.0 |
35 |
27.0–37.5 |
32.1 |
Head profile rounded to slightly acute anteriorly, mouth terminal. Maxillary extending posteriorly to vertical slightly anterior to middle of pupil. Adipose eyelid well developed. Premaxillary teeth in three rows; teeth of third row largest. Five (7), 6 (16), 7 (10) or 8 (1) tricuspidate teeth in outer series. Two (4), 3 (25), or 4 (7) tri- to pentacuspidate teeth in second, inner premaxillary row, plus 3 (30) or 4 (6) tricuspidate teeth between the first and third rows. Two teeth in third premaxillary row, medial teeth largest, symphyseal teeth smaller, both pentacuspidate. Maxillary with distal portion expanded and rounded in profile. Eleven to 18 maxillary teeth, slightly smaller than teeth of first premaxillary row, anterior teeth tricuspidate, posterior teeth unicuspidate. Dentary with 6 (1), 7 (3), 8 (1), 9 (1), or 10 (1) teeth in main series. Anterior four dentary teeth assymetrical, considerably larger and bulkier than remaining teeth, tetra- to pentacuspidate, each with central cusp distinctly larger than remaining cusps. Remaining dentary teeth progressivelly smaller, tri- to unicuspidate. Inner (lingual) series consisting of a single unicuspid symphyseal tooth, considerably smaller than teeth of main series anterior to it, plus row of 5 small, unicuspidate teeth, originating at level of 7th tooth of main series.
Scales cycloid. Lateral line complete, from supracleithrum to caudal-fin base. Forty-three (1), 44 (3), 45 (6), 46 (10), 47 (12), 48 (3), or 49 (1) scales in lateral line series; laterosensory tube simple, tube often deflected downwards. Horizontal scale rows between dorsal-fin origin and lateral line 8 (17), 9 (16), or 10 (3). Horizontal scale rows between lateral line and pelvic-fin 4 (4), 5 (15), or 6(17). Circumpeduncular scales 16 (18), 17 (9), or 18 (9).
Dorsal-fin rays ii, 9. Dorsal fin origin slightly anterior to middle of SL. First dorsal-fin pterygiophore inserting behind neural spine of 12th vertebrae. Dorsal fin displaying numerous (c. 10–35 per fin-ray main branch) small hooks on last unbranched and posterior main branch of all branched rays in one specimen (ROM
55348
, 128.8 mm SL). Anal-fin rays iii (not including first, small unbranched ray only visible in the cs specimen), 19 (1), 20 (6), 21 (16), 22 (12), or 23 (1). First anal-fin pterygiophore inserting behind haemal spine of 22th vertebrae. Last unbranched and anterior 2–3 branched anal-fin rays longer, remaining rays progressively shorter towards anal-fin end. Anal fin displaying numerous (c. 15–35 per fin-ray main branch) small hooks associated with dense, gelatinous tissue on last unbranched and posterior main branch of all branched rays except posteriomost ray in one specimen (ROM
55348
, 128.8 mm SL). Small hooks also present in the anterior main anal-fin branch in the two anteriormost anal-fin rays. Sheath of scales composed of a single series composed by 16–20 rectangular scales, covering basis of anal-fin rays. Pectoral-fin rays i, 11 (1), 12 (15), 13 (18), or 14 (2). Pelvic-fin rays i,7. Branched pelvic-fin rays with minutes hooks (c.10 per branch) on distal portion of posterior ray branches in one specimen (ROM
55348
, 128.8 mm SL). Main caudal-fin rays 10/9. Caudal fin forked, lobes rounded.
Four branchiostegal rays. First gill arch with 11(1) lower gill rakers, 11(1) upper gill rakers and 1 at angle. Vertebrae 43 (1). Supraneurals 9 (1).
FIGURE 7.
Brycon stolzmanni
, lectotype, NMW 62731:1, 124.5 mm SL: Peru, Cajamarca, Chota.
FIGURE 8.
Brycon stolzmanni
, ROM 52237, 160.5 mm SL: Peru, Cajamarca, Río Huacabamba.
Coloration in alcohol.
Top of head, snout, supraorbital, sixth and dorsal portion of fifth infraorbitals, and dorsal portion of body dark grey to dark brown. Dentary, maxillary, lower infraorbitals, gular area and ventral portion of body light to cream-colored. Opercle dark-colored, its lower half dark-grey, suffused with silvery pigmentation, while upper half dark brown. Humeral blotch present, split in two halves, lower half more conspicuous, roughly triangular-shaped, with the apex directed downwards, crossed at its lower portion by the lateral line, extending horizontally from the third to the fifth to sixth lateral line scales. Upper half of humeral blotch less conspicuous, separated from lower half of humeral blotch by a narrow clear-colored area, two and a half scales rows high. Caudal peduncle blotch present, relatively conspicuous, rounded, extending throughout 3–4 last lateral line scales into basis of 3–4 innermost caudal-fin rays. Caudal, anal and dorsal-fins with numerous small dark chromatophores scattered over interradial membranes. Pectoral and pelvic-fins with relatively few dark chromatophores on interradial membranes. Adipose fin dark brown, with a conspicuous clear-colored rounded spot at its basis.
FIGURE 9.
Brycon stolzmannni
, ZUEC 6850, 101.4 mm SL, Peru, Amazonas, Río Tingo.
Sexual dimorphism.
The single examined specimen bearing hooks on dorsal, pelvic- and anal-fins (ROM
55348
, 128.8 mm SL) was found to be a male upon dissection. The largest specimen examined, NMW 62728 (214.0 mm SL), is a female with well-developed ovaries, which does not possess fin hooks.
Distribution.
Brycon stolzmanni
is known from the upper
Río
Marañon
and its tributaries at the Departamentos
Cajamarca
,
Lambayeque
, and
Amazonas
,
Peru
(
Fig. 10
).
Fowler (1943: 4)
and
Howes (1982: 44)
incorrectly assigned the species for the Pacific slope of the Andean cordillera.
FIGURE 10.
Map of northwestern South America showing known localities of
Brycon stolzmanni
(red dots), and
B. coxeyi
(black dots).
Ecological notes.
Brycon stolzmanni
is recorded from Andean rivers in altitudes ranging at least from 870– 1087 meters high. The
type
locality, Chota, is situated in the headwaters of the
Río
Chamaya, a tributary of the upper
Río
Marañon
, at a considerably higher altitude (2400 meters high). However, its is uncertain whether the
type
specimens were collected at Chota itself or in a neighboring river valley, and consequently we did not included this record in the altitudinal range cited above. The
Río
Marañon
and its tributaries at the area of occurrence of
Brycon stolzmanni
are swift-flowing, white-water rivers possessing coarse gravel and rocky substrates running over braided channels, deeply entrenched in valleys crossing the mountains.
Remarks.
Steindachner (1879a: 152)
succinctly described
Brycon stolzmanni
, a complete description and a illustration of the species appearing a little later (1879b: 22). The species was described based on two specimens collected at Chota, upper Río Marañon basin, Departamento Cajamarca, Peru. The two syntypes (NMW 62731) were examined, the largest of which is herein designated as the lectotype of the species. There have been almost no subsequent published information on the species, and in fact,
Pearson (1937)
report of the species for several localities in the upper Río Marañon basin in Peru was the sole paper to add original information on the species up to now.
Material examined.
Type
material.
NMW
62731:1 (
1, 124.5 mm
SL):
Chota
(
Peru
, Depto.
Cajamarca
,
Rio Marañon
basin, c.
6°33’S
,
78°39’W
); Stolzmann, no date
.
Lectotype
by present designation of
Brycon stolzmanni
Steindachner.
NMW
62731:2 (1,
88.4 mm
SL); same data as lectotype
. Paralectotype.
Non
types
.
All
from
Peru
,
Rio Maranõn
drainage. Departamento
Cajamarca
:
ROM
52237 (5 of 51, 146.8–
160.5 mm
SL), approx.
74 km
W of road going N to
Jaen
,
between Pucara and Guabal, Chamaya River, Huacabamba River
(tributary
Amazon
/
Marañon
drainage), c.
5°57’S
,
79°13’W
;
E. Holm
&
J. Patalas
,
8 Jul 1986
.
CAS
77371 (69,
27.3–72.5 mm
SL),
Rio
Crisnejas, at mouth of
Rio
Paipay at
Paipay
, c.
7°21’S
,
77°53’W
; N.E. Pearson,
Aug 1923
. NMW 62728 (1, 214.0 mm SL);
NMW
62933 (1,
88.5 mm
SL),
Celendín
,
Hacienda Callacate
,
6°46'S
,
78°16'W
;
W. Taczanowski
, 1880.
MUSM
41333
(9,
20.5–37.2 mm
SL):
Celendín
,
Río
Llanguat (
Río Marañon
basin),
6°47’19’’S
,
78°12’55’’W
;
H. Ortega
et al
.,
25 Sept 2011
.
Departamento
Amazonas
:
ROM
55347 (
1, 163.7 mm
SL),
Luya
,
Huanabamba
, about
16 km
by road upstream from
Balsas
,
Amazon
/
Marañon
drainage,
6°52'S
,
78°00'W
;
E. Holm
et al.
,
27 June 1986
.
ROM
55348 (2, 128.8–
132.7 mm
SL), confluence of “El
Río
” (creek running through
Balsas
) at
Puerto Balsas
,
6°50'S
,
78°01'W
; E. Holm
et al.
,
28 Jun 1986
. UMMZ 185306 (28,
49.6–130.7 mm
SL);
UMMZ
216716
(5, 107.3–
185.5 mm
SL):
Rio Maranõn
at
Balsas
,
6°50’S
,
78°1’W
;
N.E. Pearson
,
July 1923
.
CAS
77370 (ex IU 17599) (6 of 94,
20.9–33.2 mm
SL),
Río Marañon
,
Pusoc
(
Guayabamba
), above
Balsas
, c.
6°57’S
,
78°00’W
;
N.E. Pearson
,
Aug 1923
.
CAS
77372 (32,
21.5–42.9 mm
SL),
Río Marañon
at
Tingo de Pauca
, mouth of
Río
Crisnejas, c.
7°20’S
,
77°49’W
; N.E. Pearson,
Sept 1923
.
MUSM
10611
(5, 65.8–94.0 mm SL):
Río
Uctubamba,
Lluhuana
;
F. Chang
,
23 Nov 1996
.
MUSM
40548
(1, 85.0 mm SL):
Bongará
,
Shipasbamba
,
Río
Uctubamba (trib.
Río Marañon
),
5°54’45’’S
,
78°3’50’’W
; M. Jaico
et al.
,
12 Jul 2011
. MUSM 41145 (44,
45.9–105.2 mm
SL);
ZUEC
6850
(4,
58.9–101.4 mm
SL):
Amazonas
,
Bongara
,
Jazan
,
Río
Tingo (trib.
Río
Uctubamba),
5°55’2’’S
,
78°4’35’’W
;
M.
Hidalgo
&
I. Corahua
,
29 June 2011
.
MUSM
41146
(8, 62.1–99.0 mm SL):
Amazonas
,
Bongara
,
Jazan
,
Río
Utcubamba (island),
5°55’1’’S
,
78°4’32’’W
;
M.
Hidalgo
&
I. Corahua
,
29 June 2011
.
Departamento
Lambayeque
:
MUSM
30230
(1,
35.5 mm
SL):
Ferreñafe
,
Kañaris
,
CCA
Huancabamba
,
Río
Cañariaco, mouth at
Río
Huancabamba,
5°56’15’’S
,
79°15’47’’W
; B. Renjifo & V. Meza,
24 May 2007
.
Without data:
MUSM uncat. (
1, 133.7 mm
SL, cs).