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Gymnotus ucamara: a new species of Neotropical electric fish from the Peruvian Amazon (Ostariophysi: Gymnotidae), with notes on ecology and electric organ …


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A new species of Neotropical electric fish, Gymnotus ucamara, is described from floodplain habi-tats in the Rio Ucayali Basin, Peru. The new species is distinguishable from all congeners by the following combination of characters: a clear patch at the caudal end of the anal fin; two laterosen-sory canal pores (from the preopercular-mandibular series) in the dorso-posterior portion of the pre-opercle; a coloration pattern with 18–24 dark brown bands separated by narrow pale interbands which are less than one-third the width of the dark bands; a long head (12.2–13.4 % total length); many (10–11) scales rows over the anal fin pterygiophores; few (38-43) pored lateral-line scales to the first lateral-line ramus; and a low (75–91) total number of pored lateral-line scales.
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Accepted: 15 August 2003; published: 29 August 2003
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Copyright © 2003 Magnolia Press
Zootaxa 277: 1-18 (2003)
Gymnotus ucamara: a new species of Neotropical electric fish from
the Peruvian Amazon (Ostariophysi: Gymnotidae), with notes on
ecology and electric organ discharges
Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611-7800, USA; E-mail:
Department of Zoology, University of Manitoba, Winnipeg, MB, R3T 2NZ Canada; E-mail:
A new species of Neotropical electric fish, Gymnotus ucamara, is described from floodplain habi-
tats in the Rio Ucayali Basin, Peru. The new species is distinguishable from all congeners by the
following combination of characters: a clear patch at the caudal end of the anal fin; two laterosen-
sory canal pores (from the preopercular-mandibular series) in the dorso-posterior portion of the pre-
opercle; a coloration pattern with 18–24 dark brown bands separated by narrow pale interbands
which are less than one-third the width of the dark bands; a long head (12.2–13.4 % total length);
many (10–11) scales rows over the anal fin pterygiophores; few (38-43) pored lateral-line scales to
the first lateral-line ramus; and a low (75–91) total number of pored lateral-line scales.
Key Words: biodiversity, electrogenesis, Gymnotiformes, várzea
The weakly electric Neotropical fish genus Gymnotus has been the subject of several taxo-
nomic studies in recent years (Mago-Leccia 1994; Albert & Miller 1995; Campos da Paz
1996; Campos da Paz & Costa 1996; Albert et al. 1999; Campos da Paz 2000; Albert
2001; Albert & Crampton 2001; Campos da Paz 2002). Until recently Gymnotus was rec-
ognized as the only genus in the family Gymnotidae. The monotypic genus Electrophorus
Gill, comprising the single strongly electric species Electrophorus electricus (L.) was
recently included in the Gymnotidae (Albert 2001).
2 © 2003 Magnolia Press
TABLE 1. Nineteen valid species of Gymnotus with affiliation to species groups (see text) and geo-
graphical range. MA, Atlantic and Pacific slopes of Middle America; OR, Orinoco basin including
Trinidad; GU, Guyanas and upper Rio Negro; AM, Amazon basin; NE, coastal drainages of north-
east Brazil; SE, coastal drainages of southeast Brazil and Uruguay; PA, Paraguay-Para basin.
Sources: Albert (2001), Albert & Crampton (2001), unpublished observations.
Albert (2001) and Albert and Crampton (2001) summarized the diagnostic characters
of Gymnotus. Albert and Miller (1995) and Albert (2001) recognized three species groups
within the genus based on color pattern, body proportions and counts. These are the G.
cylindricus, G. pantherinus,andG. c a ra p o species-groups. The species composition and
geographical range of these groups are summarized in Table 1. The G. cylindricus species-
group is endemic to both Atlantic and Pacific drainages of Middle America and comprises
just two species. The G. c ar a po species-group is endemic to South America and is repre-
sented by seven species distributed from the Pacific slope of Colombia to the Pampas of
Argentina. The G. pantherinus species-group is represented by nine species with distribu-
Group Species Geographical range
cylindricus Gymnotus cylindricus La Monte, 1935 MA
Gymnotus maculosus Albert & Miller, 1995 MA
carapo Gymnotus arapaima Albert & Crampton, 2001 AM
Gymnotus bahianus Campos da Paz & Costa, 1996 NE
Gymnotus carapo Linnaeus, 1758 GU, OR, AM
Gymnotus diamantinensis Campos da Paz, 2002 AM
Gymnotus inaequilabiatus (Valenciennes, 1847) SE, PA
Gymnotus mamiraua Albert & Crampton, 2001 AM
Gymnotus sylvius Albert & Fernandes-Matioli, 1999 SE, PA
Gymnotus ucamara n. sp. AM
pantherinus Gymnotus anguillaris Hoedeman, 1962 GU, OR, AM, PA
Gymnotus cataniapo Mago-Leccia, 1994 GU, OR, AM
Gymnotus coatesi La Monte, 1935 AM
Gymnotus jonasi Albert & Crampton, 2001 AM
Gymnotus melanopleura Albert & Crampton, 2001 AM
Gymnotus onca Albert & Crampton, 2001 AM
Gymnotus pantherinus (Steindachner, 1908) SE
Gymnotus pedanopterus Mago-Leccia, 1994 GU, OR, AM
Gymnotus stenoleucus Mago-Leccia, 1994 GU, OR, AM
© 2003 Magnolia Press 3
tions from Panama to Paraguay. Species in the G. carapo species-group, including the new
species described here, can be distinguished from species in the G. pantherinus and G.
cylindricus species-groups by the possession of a clear or pale patch near the caudal end of
the anal fin, and two (vs. one) laterosensory canal pores in the preopercular-mandibular
series of the dorso-posterior portion of the preopercle. We use the above classification of
Gymnotus as a basis for the differential diagnosis of the newspeciesdescribed in this report.
There are currently 18 valid species of Gymnotus, of which thirteen are found in the Ama-
zon basin. Several new species of Gymnotus have recently been discovered in the Brazil-
ian portion of the Amazon basin (Albert & Crampton 2001; Campos da Paz 2002),
including seven new species from whitewater floodplains or rzeas along the Amazon
River’s main stem (Albert & Crampton 2001). Here we describe a new species from
várzea floodplains of the Rio Ucayali Basin in the Peruvian Amazon.
Materials and methods
Specimens and their electric organ discharges (EODs) were captured from a site in the Rio
Ucayali floodplain, Peru (Figs. 1, 2). Additional material was acquired from museum col-
lections. Museum acronyms follow Leviton et al. (1985), with the addition of IIAP (Insti-
tuto de Investigaciones de la Amazonía Peruana, Iquitos), INPA (Instituto Nacional de
Pesquisas da Amazônia, Manaus), MUSM (Museo de Historia Nacional de la Universidad
Nacional Mayor de San Marcos, Lima), NRM (Swedish Museum of Natural History,
Stockholm), and UUZM (Uppsala University Zoological Museum, Uppsala).
Measurements and counts (Tables 2, 3) follow Albert and Crampton (2001) except for:
APS, anal fin pterygiophore scales as the number of scale rows over the pterygiophores
counted from an origin vertically below the base of the first lateral-line ramus; CEP, caudal
electroplate rows counted (with backlighting and with overlying scales removed) as the
number of horizontally aligned rows of electroplates in the electric organ at a distance of
one head length from the tip of the caudal appendage; MW, mouth width at rictus; PLR,
number of pored lateral-line scales in posterior lateral-line posterior to neurocranium and
counted to first ramus of the lateral-line; PLS, total number of pored lateral-line scales in
posterior lateral-line posterior to neurocranium. All measurements were taken with digital
calipers to the nearest 0.1 mm on the left side of specimens. Measurements reported as a
percentage of total length (TL) (i.e. head length, anal-fin length, body depth and body
width) and anal-fin ray counts were not included for specimens with damage to the caudal
appendage amounting to more than an estimated 5% of un-damaged TL. Counts of anal-
fin rays and precaudal vertebrae were taken from radiographs. Osteological data were
taken from specimens cleared and stained following the technique described by Dingerkus
and Uhler (1977).
4 © 2003 Magnolia Press
FIGURE 1. Map of part of the Pacaya-Samiria National Reserve in Loreto, Peru, illustrating the
lower Rio Pacaya and the type-series locality of Gymnotus ucamara n. sp. (1). Floodplain areas
(stippled) experience an annual flood regime of up to 7 m amplitude. Base map traced from 1998
1:300,000 Landsat TM5 images.
© 2003 Magnolia Press 5GYMNOTUS UCAMARA SP. N.
FIGURE 2. Type-series locality of Gymnotus ucamara n. sp. A small drainage channel between
Rio Pacaya and Cocha Zapote, Pacaya-Samiria National Reserve, Loreto, Peru. Floating aquatic
vegetation in the foreground is dominated by Pistia stratiotes, Azolla sp., and Eichhornia crassipes.
Rooted grasses in the background include Cyperus sp. and Paspalum sp. These grasses form float-
ing rafts during the high water season. The high-water mark from the preceding flood season is vis-
ible on the trunk of a cecropia tree in the back-left of the photograph.
EOD recording techniques follow Crampton (1998). Specimens were recorded in
water from the capture locality at temperatures between 27 and 29 ºC soon after capture.
Field numbers for EOD-recorded fish follow a standard format: e.g. WGRC 09.200902
(ninth gymnotiform specimen collected and recorded on September 20 2002). Recordings
of pulse repetition rate during the day and night were taken from specimens isolated in
large (50 l) buckets of water provided with submerged vegetation, placed in a disturbance
and vibration-free place, and exposed to a subdued natural light regime. Nighttime record-
ings were taken between 1900 and 2100 (hours of peak swimming activity) on the day of
capture. Daytime recordings were taken between 1000 and 1200 on the following day.
Gymnotus ucamara n. sp.
(Fig. 3)
Holotype. UF 126182 (156.0 mm TL, WGRC 09.200902), Peru, Loreto, Rio Ucayali,
Rio Pacaya, Cocha Zapote, in Pacaya-Samiria National Reserve, 05°20.03'S, 74°29.08'W,
collected by J. Albert, W. Crampton, N. Lovejoy, H. Ortega and R. Reis, 9 September
6 © 2003 Magnolia Press
Paratypes. UF 126121 (1, 174 mm TL, WGRC 02.200902); UF 126183 (1, 172 mm
TL, EOD not recorded); UF 126184 (2, 190 mm TL, WGRC 12.200902; 146 mm TL,
WGRC 13.200902). All collected by J. Albert et al. with holotype.
Nontypes. MUSM 9274 (1, 134 mm TL), Loreto, Contamana, Aguas Calientes,
approx. 07°02'S, 74°14'W, 3 June 1996; MUSM 10184 (7, 117–156 mm TL, 2 cleared and
stained), Loreto, Contamana, Rio Ucayali, approx. 07°02'S, 74°14'W, 31 May 1996. All
FIGURE 3. Photographs of body and head of the holotype of Gymnotus ucamara n. sp. (UF
126182). Scale bar = 10 mm.
Diagnosis. Gymnotus ucamara differs from other species in the Gymnotus carapo spe-
cies-group in possessing the following unique combination of characters: a coloration pat-
tern with 18-24 dark brown bands separated by narrow pale interbands which are less than
one-third the width of the dark bands (a pattern that is readily distinguishable from all
other described species of the G. carapo species-group except G. mamiraua); a long head
(12.2–13.4 % total length vs. 7.9–11.8 % in all other species except G. ca r ap o and G. ara -
paima); many (10
11) scales over anal fin pterygiophores (vs. 4–9 in all other species
except G. arapaima); few (38
43 [median 42]) pored lateral-line scales to first ramus (vs.
32–38 [median 37] in G. mamiraua,vs.42
52 [median 48] in G. c ar apo, and vs. 50–64 in
all other species); a low (75-91 [median 82]) total number of pored lateral-line scales (vs.
93–108 [median 98] in G. c a r a po , and vs. 106–140 in all other species except G. mamiraua
with 75–79 [median 78]), and a relatively large eye (orbital diameter 0.09–0.10 % HL vs.
0.06–0.07 % in G. c a rapo). G. ucamara is superficially most similar to G. mamiraua from
which it can be readily distinguished on the basis of the following characters; a long head
(12.2–13.4 % total length vs. 9.7–10.7 % total length in G. mamiraua) and relatively more
pored lateral line scales to first ramus (38
43 [median 42] vs. 32–38 [median 37] in G.
© 2003 Magnolia Press 7
TABLE 2. Morphometric data for adults of eight species of Gymnotus in the G. c a ra p o species-
group. Abbreviations: TL, total length; HL, head length; PR, preorbital distance; PO, postorbital
distance; IO, interorbital distance; MW, mouth width; HD, head depth; HW, head width; BD, body
depth; BW, body width; PA, preanal distance; P1, pectoral-fin length; AF, anal-fin length. TL and
HL expressed in mm. Percentage measurements in HL or, if marked with an asterisk, in TL. BW/
BD expressed as a ratio. N values (in parentheses) vary because measurements were excluded from
some specimens with damage (see text) or unusual preservation artifacts. NA, data not available. †,
data from original published description. All data from specimens collected in the region of the type
TABLE 2. cont
Species max. TL HL %HL* Mean %PR Mean %MW Mean
G. arapaima
545 (32) 14.9-31.9
13.6 32.2-38.5
35.2 31.2-36.7
G. bahianus
241 (13) 14.8-25.5
12.4 32.4-35.7
34.2 26.0-28.0
G. c a r a p o
317 (17) 17.7-38.9
12.3 34.6-39.1
36.6 31.1-47.6
G. diamantinensis
125 (3) 11.5-13.5
11.2 33.0-34.4
33.6 26.9-28.1
G. inaequilabiatus
998 (15) 18.7-82.0
10.5 30.2-37.3
35.0 34.9-44.2
G. mamiraua
228 (13) 18.1-22.4
10.4 31.3-35.5
33.3 34.3-41.6
G. sylvius
307 (6) 20.5-38.5
12.9 33.9-36.1
34.9 NA NA
G. ucamara n. sp.
190 (13) 15.2-23.1
12.7 33.3-38.2
35.9 37.2-46.8
%PO Mean %IO Mean %HD Mean %HW Mean
G. arapaima
62.0 29.0-36.5
33.1 50.7-56.6
54.1 46.0-57.9
G. bahianus
63.7 32.8-40.3
35.8 55.1-59.8
56.7 52.4-58.0
G. c a r a p o
61.1 36.0-42.3
38.5 52.1-65.4
57.5 56.6-64.1
G. diamantinensis
64.5 41.1-42.9
42.2 65.2-69.6
67.1 NA NA
G. inaequilabiatus
62.8 37.0-45.7
42.5 61.7-73.8
66.0 64.9-72.0
G. mamiraua
63.6 32.4-43.2
37.8 60.9-70.7
67.1 55.6-68.6
G. sylvius
59.8 36.4-38.2
37.5 57.1-60.5
58.4 59.5-61.8
G. ucamara n. sp.
60.4 32.9-43.2
36.5 56.5-65.0
59.1 53.9-65.5
8 © 2003 Magnolia Press
TABLE 2. cont.
TABLE 2. cont.
Description. Body shape and pigment patterns illustrated in Fig. 3. Morphological and
meristic data presented in Tables 2 and 3. Cephalic sensory canal pore configurations sum-
marized in Fig. 4. Size up to 190 mm TL. Size at maturity unknown. Sexual dimorphism
unknown. Scales cycloid, ovoid, present on entire post-cranial portion of body from nape
to tip of caudal appendage. Scales on dorsal surface relatively large at mid-body, six rows
from lateral-line to dorsal midline. Scales small over pterygiophores, 10
11 scale rows.
Lateral-line scales (in holotype) approximately 1.3 mm high by 1.5 mm long in humeral
region, 2.3 mm high by 2.6 mm long at midbody, 1.4 mm high by 2 mm long dorsal to
Species PA% Mean %P1 Mean %AF* Mean %BD* Mean
G. arapaima
65.1 39.6-47.9
43.5 71.4-82.9
79.2 8.9-11.6
G. bahianus
83.4 38.3-45.9
42.3 80.0-82.3
81.2 11.3-12.6
G. c a r a p o
79.6 37.4-55.0
43.2 71.1-88.9
79.7 10.1-11.7
G. diamantinensis
81.7 36.3-41.1
39.4 81.8-82.3
82.1 10.6-10.9
G. inaequilabiatus
77.1 36.8-51.0
45.7 77.8-85.2
81.7 7.5-12.0
G. mamiraua
74.3 41.6-49.5
45.1 72.4-87.7
82.2 9.2-12.6
G. sylvius
NA NA 41.6-46.7
45.1 74.5-79.2
77.7 10.3-13.1
G. ucamara n. sp.
70.1 46.2-55.3
49.7 75.7-87.2
80.1 10.0-12.2
Species %BW* Mean BW/BD Mean
G. arapaima
6.4 0.52-0.72
G. bahianus
G. c a r a p o
7.5 0.63-0.81
G. diamantinensis
G. inaequilabiatus
6.7 0.54-0.77
G. mamiraua
6.2 0.53-0.72 (7) 0.58
G. sylvius
7.4 0.67-0.72
G. ucamara n. sp.
7.7 0.63-0.73
© 2003 Magnolia Press 9
anterior margin of clear patch on anal fin. Gape size in mature specimens large, extending
beyond posterior nares. Mouth position superior, lower jaw longer than upper, rictus
decurved. Chin fleshy and bulbous with thick pad of electroreceptor organs and support
tissues overlying tip of snout and oral jaws. Anterior narial pore included within gape in
large narial fold. Anterior nares large, subequal to diameter of eye. Branchial opening
moderate (32–40 % in HL). Circumorbital series ovoid. Ethmoid region between anterior
nares moderate, its anterior margin rounded. Eye position lateral, lower margin of eye
slightly ventral to rictus. Eye relatively large, orbital diameter 0.09–1.0 % HL. Premaxilla
and dentary with one or two rows of large, slightly recurved, conical teeth. Premaxilla with
11-12 (mode 12, n = 3) teeth disposed in single row along outer margin. Dentary with 16
(n = 2) teeth disposed in single row along outer margin.
FIGURE 4. Head of the holotype of Gymnotus ucamara n. sp. illustrating organization of cephalic
sensory canals and pores. Centerline of canals (ossified and unossified) indicated by dashed lines.
Pores indicated by small circles. Eye and anterior and posterior nares shaded gray. Abbreviations:
so, supraorbital; io, infraorbital; pl, posterior lateral-line; pm, preopercular-mandibular; st,
supratemporal; m, medial. Scale bar = 5 mm. Pore S01b is absent in some specimens.
Rib 5 approximately same width as rib 6. Body cavity of moderate length with 3234
(mode 33) precaudal vertebrae. Hemal spines present. Gas bladder not extending beyond
first hemal spine. Displaced hemal spines absent. Multiple anal-fin ray branching posterior
to rays 10
17. Variable number (11-19) of asymmetrically arranged lateral-line rami
extending posteroventrally at posterior end of lateral line. Dorsal lateral-line rami absent in
all specimens examined. Anal-fin pterygiophores at posterior portion of body cavity
shorter than first hemal spine. Caudal appendage short, less than half pectoral-fin length in
undamaged and unregenerated specimens. Single hypaxial electric organ, extending along
entire ventral margin of body. Three or four (mode 4) rows of electroplates at one HL dis-
tance from end of caudal appendage.
10 © 2003 Magnolia Press
TABLE 3. Meristic data for eight species of Gymnotus in the G. c ar a p o species-group. Abbrevia-
tions: BND, dark bands; AFR, anal-fin rays; P1R, pectoral-fin rays; SAL, scales above lateral line;
CEP, caudal electroplate rows; APS, anal-fin pterygiophores scales; PCV, precaudal vertebrae;
PLR, pored lateral-line scales to first ramus; PLS, total pored lateral-line scales; LRV, lateral-line
ventral rami (left or right); LRD, lateral-line dorsal rami (left or right). Med., median value. N val-
ues (in parentheses) vary because measurements were excluded from some specimens with damage
(see text) or unusual preservation artifacts. NA, data not available. †, data from original description.
All data from specimens collected in the region of the type localies
TABLE 3. cont.
TABLE 3. cont
Species BND Med. AFR Med. P1R Mode SAL Mode
G. arapaima
20-24 (20) 22 225-265 (17) 235 15-17 (20) 15 6-9 (18) 7
G. bahianus
0 (13) 0 201-226 (NA) 203 17-18 (NA) 17 NA NA
G. c a r a p o
16-21 (8) 19 225-245 (6) 240 14-16 (10) 16 6-7 (8) 6
G. diamantinensis
16-19 (2) NA 195-210 (3) 201 14-15 (3) 14 8-10 (3) 9
G. inaequilabiatus
19-24 (10) 22 170-260 (6) 220 13-16 (11) 15 6-9 (10) 6
G. mamiraua
17-21 (11) 20 195-265 (11) 225 15 (13) 15 5-9 (11) 5
G. sylvius
21-24 (5) 22 220-230 (6) 224 16 (2) 16 8 (2) 8
G. ucamara n. sp.
18-24 (13) 21 220-245 (13) 235 15-16 (13) 15 6 (13) 6
Species CEP Mode APS Mode PCV Mode PLR Med.
G. arapaima
3-4 (16) 4 9-13 (31) 12 33-37 (21) 35 53-64 (27) 57
G. bahianus
3-5 (NA) NA NA NA 33-34 (NA) NA NA NA
G. c a r a p o
3-4 (7) 4 7-9 (7) 8 33-34 (8) 33 45-52 (7) 48
G. diamantinensis
G. inaequilabiatus
3-5 (10) 4 NA NA 31-33 (6) 32 35-37 (4) 36
G. mamiraua
3-4 (6) 4 5-6 (6) 6 31-34 (8) 33 32-38 (8) 37
G. sylvius
NA NA 6-8 (5) NA 32-35 (5) 33 NA NA
G. ucamara n. sp.
4 (5) 4 10-11 (13) 10 32-34 (13) 33 38-43 42
Species PLS Med. LRV Med. LRD Med.
G. arapaima
99-108 (17) 102 10-22 (11) 15 0 (11) 0
G. bahianus
79-93 (NA) 90 NA NA NA NA
G. c a r a p o
93-103 (8) 98 8-22 (8) 12 0 (8) 0
G. diamantinensis
G. inaequilabiatus
82-115 (4) 90 7-16 (6) 15 0 (6) 0
G. mamiraua
75-103 (12) 78 1-14 (6) 10 0 (6) 0
G. sylvius
85-100 (5) 93 NA NA NA NA
G. ucamara n. sp.
75-91 (13) 82 11-19 (13) 15 0 (13) 0
© 2003 Magnolia Press 11
Color in life.1824 (median 21, n = 13) broad, dark, chocolate-colored bands, sepa-
rated by narrow, pale interbands (sensu Albert et al. 1999) less than one-third the width of
the dark bands. Slight countershading in specimens longer than 150 mm TL, more pro-
nounced anteriorly. Pale interbands extend from pectoral-fin base to tip of caudal append-
age and oriented obliquely (anterior-ventral to posterior-dorsal). Dark bands occur singly
(never divided into band pairs sensu Albert et al. 1999) and are occasionally divided into
Y or inverted-Y shapes but never divided into X shapes on anterior two-thirds of body.
Pale interbands sometimes interrupted. Pigment density slightly greater at the dark band
margins than in the middle at mid-body. Band-interband margins wavy and highly con-
trasted with one another. Pale interbands irregular in shape and width, narrower and more
regularly shaped anteriorly. Pale interbands usually do not extend to mid-dorsum along
anterior 2/3 of body. Incomplete pale interband present in middle of some dark bands.
Three pale interbands from either side terminate near ventral midline, often not meeting,
betweentheanusandanal-finorigin. One or two bands lie posterior to last anal-fin ray.
FIGURE 5. EOD waveform (A) and Fourier Power Spectrum (B) of holotype of G. ucamara n. sp.
The EOD is plotted with head-positivity upwards and its component phases labeled P-1 through P3.
P1 represents the dominant positive component. The Power Spectrum was computed from a 2048
point Fast-Fourier-Transform and the Peak-Power-Frequency scaled to the minimum attenuation of
0.5 ms
Frequency (kHz)
Amplitude (dB
12 © 2003 Magnolia Press
Head never banded, spotted or blotched, uniformly dark brown but slightly paler in
gular region. Numerous minute chromatophores speckled over branchiostegal membranes
and ventral surface of head. Pectoral-fin rays dark brown or black, interradial membranes
hyaline. Anal fin never blotched, spotted or marked. Anal fin rays and membrane dark
gray or black on anterior 80% of fin length, translucent on posterior 20%. Color variation
is not known to be correlated with size, sex or EOD waveform. Specimens fixed in 10%
formalin and preserved for 1-6 years in 70% ethanol maintain approximate colors of life,
although the darker pigments sometimes pale with time.
Electric organ discharge. G. ucamara n. sp. generates EODs as discrete pulses of 1.25
–1.73 ms duration (mean 1.51, n = 5). These comprise four or five phases (Fig. 5). The
waveform comprises a dominant tri-phasic component (P0, P1, P2) with a duration of
approximately 0.78–0.92 ms (mean 0.87, n = 5) followed by a low-voltage positive final
phase (P4). A very low-voltage initial positive phase (P-1) precedes P0 in most specimens.
The Peak Power Frequency (PPF) (Fig. 4) of the Fourier Transform of EODs of G. u c a-
mara n. sp. ranges from 1.71–1.95 kHz (mean 1.78, n = 5).
The EOD pulse repetition rate of G. u c amar a n. sp. is relatively low and less variable
during the day when this species lodges itself into the submerged root mats of floating
plants (range 44.5–45.9 Hz, mean 45.3, standard deviation [SD] 0.3, n = 4). G. ucamara n.
sp. can instantaneously increase its EOD pulse repetition rate to around 90–110 Hz in
response to a sudden stimulus such as a loud underwater noise or a light prod with a glass
rod. Following such a ‘fright response’ the EOD repetition rate returns to close to the nor-
mal resting rate within a few milliseconds and back to the normal resting rate within a few
seconds. The EOD pulse repetition rate is usually higher and more variable at night. The
highest pulse rates occur during swimming (range 62.5–76.9 Hz, mean 69.4, SD 6.2, n =
4) and the lowest rates occur when a specimen stops swimming, usually by resting its body
against a submerged structure, or wedging itself between submerged roots (range 50.0–
66.7 Hz, mean 59.7, SD 8.7, n = 4).
Distribution. Known only from the lowland Rio Ucayali basin in Peru, at sites near
Contamana and in the Rio Pacaya-Samiria National Reserve near the confluence of the
Rio Ucayali and Rio Marañon.
Habitat and Ecology. All the type specimens were captured from static, vegetation-
choked water in a shallow (maximum depth 0.5 m) channel connecting a floodplain lake
(Cocha Zapote) to the Rio Pacaya (Figs. 1,2). The habitat structure, vegetation and water
quality of the locality are typical of whitewater floodplains of the Central and Upper Ama-
zon (Ayres 1993; Junk 1997). The type specimens were captured during the low-water
month of September. Aquatic vegetation at the site consisted of plants typical of floating
meadows, an important substrate for floodplain gymnotiform fish communities throughout
the year (Crampton 1996; Albert & Crampton 2001). The dominant species were Cyperus
sp., Eichhornia crassipes Solms., Pistia stratiotes (L.), Ludwigia sp., Salvinia spp., and
Utricularia sp. Water quality at the locality was recorded as: dissolved oxygen, 2.4 mg/l;
© 2003 Magnolia Press 13
electrical conductivity, 240 Scm
at 25ºC; transparency with Sechhi disc 0.6 m, surface
temperature 31.2 ºC. Other gymnotiform electric fish collected from the same locality and
habitat were Gymnotus carapo (L.), Eigenmannia sp., and three undescribed species of
Brachyhypopomus. One of the two non-type lots from Contamana (MUSM 10184) was
collected in rafts of floating vegetation along the edge of the Rio Ucayali. These rafts may
have been swept out of nearby floodplain lakes (H. Ortega pers. comm.). The other non-
type lot (MUSM 9274) was collected from floating vegetation along the edge of a sedi-
ment-laden ‘whitewater’ stream near its confluence with the Rio Ucayali. Water tempera-
ture was reported as 28ºC. This stream flows out of hot springs from nearby mountains,
but gymnotiforms were only found well downstream of the influence of unusually warm
waters (H. Ortega pers. comm.). G. ucamara n. sp. feeds on aquatic invertebrates. Stomach
content analyses of the paratype and non-type series are summarized in Table 4.
TABLE 4. Proportional composition of food items in stomachs of Gymnotus ucamara n. sp.
Autochthonous food items are aquatic invertebrates living in submerged roots and in the benthos.
Allochthonous food items have fallen into the water from the foliage of overhanging or floating
Etymology. Named for the geological term “Ucamara Depression” describing the low-
lying region between the lower reaches of the Ucayali and Marañon Rivers caused by sub-
sidence in the Upper Amazon foreland basin.
Additional materials examined.
Materials examined follow Albert et al. (1999), Albert (2001), and Albert & Crampton
(2001), with the addition of:
Gymnotus arapaima (56 specimens, 48
460 mm). Brazil: Amazonas: Rio
Solimões, Lago Calado, Município Manaus, approx. 03°07'S, 60°01'W, INPA 6387 (2,
Paratypes MUSM 10184 Mean %
1234 123456
Estimated % fullness
75 75 100 100 100 100 100 100 50 50 85%
Conchostraca (adults)
25 10 3.5
Coleoptera (larvae)
50 100 100 100 35
Coleoptera (adults)
100 50 15
Odonata (naiads)
50 100 75 90 31.5
Unidentified invertebrates
75 7.5
Lepidoptera (larvae)
50 5
Orthoptera (adult)
25 2.5
14 © 2003 Magnolia Press
255395); Cidade de Manaus, Igarapé do Quarenta, Município Manaus, approx. 03°06'S,
60°01'W, INPA 10376 (1, 255); Rio Solimões-Japurá confluence, Mamirauá Sustainable
Development Reserve (MSDR), Cano do Lago Mamirauá, 03°05.22'S, 64°48.03'W, INPA
11514 (5, 145
457), INPA 18389 (1, 55); Rio Tefé, Lago Tefé, Igarapé Curupira,
03º26.02'S, 64º43.78'W, INPA 18390 (1, 55); Rio Tefé, Lago Tefé, Estrada Agrovila,
swamp in forest nr. Igara Curupira, 03º26.02'S, 64º43.78'W, INPA 18391 (2, 48-51); Rio
Negro, Lower Rio Demini, c. 30 km upstream mouth Rio Aracá, Município Barcelos,
approx. 00°23'N, 62°51'W, MCP uncat (1, 272); Rio Tefé, nr. Cabeçeira do Lago Tefé,
03°41.39'S, 64°59.13'W, MZUSP 75165 (1, 190); Rio Solimões-Japurá confluence,
MSDR, Jarauá lake system, Ressaca do Caetono, 02°50.22'S, 64°55.79'W, MZUSP 75166
(1, 133); Rio Tefé, same locality as INPA 18390, MZUSP 75169 (1, 102); Rio Tefé, same
locality as MZUSP 75165, MZUSP 75170 (1, 147), MZUSP 75171 (1, 128), MZUSP
75172 (1, 158), MZUSP 75173 (1, 160), MZUSP 75174 (1, 128), MZUSP 75175 (1, 129),
MZUSP 75176 (1, 141); Rio Tefé, same locality as INPA 18390, MZUSP 75177 (1, 129);
Rio Tefé, Lago Tefé, Igarapé Repartimento, 03º24.46’S, 64º44.17'W, MZUSP 75178 (1,
123); Rio Solimões-Japurá confluence, MSDR, Ressaca do Pau, 03º02.30'S, 64º51.96'W,
MZUSP 75179 (1, 107). All localities from Rio Tefé and MSDR in the municipalities of
Tefé and Alvarães respectively. Mato Grosso: Rio Aripuanã, Igarapé do Castanhal,
Município Aripuanã, INPA 6390 (part) (11, 128
460). Rondônia: Rio Madeira, Rio
Jamari, nr. UHE Samuel, Município Porto Velho, approx. 08°26'S, 63°30'W, INPA uncat.
(POLO 463) (2, 115
195), INPA uncat. (POLO 482) (2, 435-460); Rio Machado, Nazaré,
Município Jí-Paraná, 10°4'59"S, 62°17'59"W, INPA uncat. (POLO 626) (1, 147); Rio
Madeira, same locality as INPA uncat. (POLO 463), INPA uncat. (POLO 872) (11, 160
252), INPA uncat. (POLO 895) (1, 185), INPA uncat. (POLO 951), (2, 183-187).
Gymnotus bahianus (25 specimens, 55
275 mm). Brazil: Bahia: Uruçuca, Fazenda
Almada, Município Ilheus, approx. 14°34'59"S, 39°15'59"W, MNRJ 4188 (2, 200
MNRJ 4346 (10, paratypes, 133
240), MNRJ 4381 (3, 84168); Pirataquice, Município
Ilheus, approx. 14°34'59"S, 39°15'59"W, MNRJ 4382 (10, 55
Gymnotus carapo (185 specimens, 32–367 mm, referring only to populations from
region of type locality [Surinam] and from the Upper Amazon).
Brazil: Amazonas: Rio
Tefé, Ilha do Martelo, 03°46.82'S, 64°59.48'W, MZUSP 75168 (1, 119); Rio Tefé,
Cabeçeira do Lago Tefé, 03°34.59'S, 64°59.32'W, MZUSP 76061 (1, 260); Rio Tefé, Lago
Tefé, Ressaca do Socorro, 03°19.18'S, 64°41.76'W, MZUSP 76062 (1, 94); Rio Solimões-
Japurá confluence, Mamirauá Sustainable Development Reserve (MSDR), Ressaca da
Vila Alencar, 03º07.70'S, 64°48.03'W, MZUSP 76063 (1, 298); MSDR, Cano do Lago
Mamirauá, 03º04.43'S, 64º48.65'W, MZUSP 76064 (1, 253); MSDR, Lago Secretaria,
03º06.74'S, 64°48.02'W, MZUSP 76066 (2, 97
136); Rio Solimões, Rio Cayari, Municí-
pio Benjamin Constante, approx. 04°22'S, 70°02'N, UMMZ 230734 (2, 190–210). All
localities from Rio Te and MSDR in the municipalities of Tefé and Alvarães respec-
Ecuador: Napo: Rio Napo, Rio Tiputini, approx. 00°49'S, 75°31'W, FMNH
© 2003 Magnolia Press 15
103329 (10, 33–320); Rio Napo, Rio Aguarico, Laguna Zancudococha, approx. 00°17'S,
75°52'W, FMNH 103334 (2, 48
64). Peru: Loreto: Rio Amazonas, Maynas, nr. Iquitos
(no locality data): IAAP (uncat.) (1, 367); Rio Ucayali, Contamana, Aguas Calientes,
approx. 07°02'S, 74°14'W, MUSM 9274 (1, 136); Rio Napo, Rio Aguarico, Maynas, PV
Castaña, 00°48.22'S, 75°14.40'W, MUSM 14482 (7, 118
198); Rio Samiria, Maynas, right
bank stream tributary to R. Samiria between Caño Pastos and Hamburgo, 05°12'S,
75°08'W, NRM 27650 (1, 305); Rio Maniti, Maynas, 50 km NE of Iquitos, 03°29'S,
72°44'W, NRM 40772 (1, 91); Rio Amazonas, Maynas, reportedly Rio Nanay (procured
from ornamental fish exporting company in Iquitos), UF 116573 (2, 189
279), UF 122820
(1, 275), UF 122822 (1, 330), UF 122825 (1, 158), UF 122847 (1, 188), UF 122848 (1,
112), UF 122849 (1, 132), UF 122850 (1, 188), UF 122851 (1, 107), UF 122852 (1, 92);
Rio Nanay, Maynas, 3 km upstream Mishana, Reserva Allpahuayo-Mishana, 03°52.08'S,
73°29.05'W, UF 116665 (1, 298); Rio Pacaya, Cocha Zapote, 05°20.03'S, 74°29.08'W, UF
126181 (2, 245
272); Rio Nanay, Rio Momon, Amazon camp near Iquitos, approx.
03°42'S, 73°16'W, UMMZ 228998 (4, 38
172); Rio Tahuayo, 04°10'S, 73°12'W, UMMZ
228999 (1, 162); Rio Javari, Buen Suceso, Quebrada Carana, approx. 04º08'S, 70º26'W,
UMMZ 230733 (1, 251). Ucayali: Rio Ucayali, Pucallpa, Estación del IVITA, Quebrada
Piscigranja, approx. 08°23'S, 74°32'W, MUSM 529 (7, 83-109), MUSM 532 (1, 181),
MUSM 537 (2, 222-260); Rio Ucayali, Rio Huacamayo km 155, 12°46'S, 69°52'W,
MUSM 1547 (1, 122); Rio Ucayali, Pucallpa, Utuguinia, approx. 08°23'S, 74°32'W,
MUSM 1757 (3, 154
267); same locality as MUSM 529, MUSM 2691 (5, 132222),
MUSM 2971 (1, 187). Surinam: unknown localities: NRM 8224 (1,331 Linnean syn-
type), UUZM 56 (1,331 Linnean syntype). Brokopondo District: Suriname River, Tapeo-
eripa creek nr. Brokopondo village, 05°04'N, 54°58'W, UMMZ 190414 (6, 71
Nickerie District: Lucie River, creek, upstream of Amotopo-Camp Geologie Rd., 03º36'N,
57º37'W, USNM 225274 (8, 81
318); Corantijn River, E bank creek, 350 m downstream
from Wilhelm II Falls, 03º34'N, 57º15'W, USNM 225275 (11, 81
270); Corantijn River,
Dalbana Creek, ca. 3 km upstream from Amotopo-Camp Geologie Rd., 04º20'N, 57º37'W,
USNM 225276 (16, 75
148); Corantijn River, Lana Creek, ca. 4 km from intersection with
W. Corantijn River, 05º28'N, 57º15'W, USNM 225284 (10, 54
143); Corantijn River,
creek south of Matapi, approx. 2 km downstream of Cow Falls, 04º59'N, 57º38'W, USNM
225285 (12, 85
257); Corantijn River, Koekwie creek, 05º31'N, 57º10'W, USNM 225286
(15, 80-319); Corantijn River, Dalibane Creek, Camp Dacclemmen, 05º34'N, 57º11'W,
USNM 225290 (19, 14
157); Corantijn River, stream on S. side Lucie River, 03º35'N,
57º39'W, USNM 225297 (14, 53
Gymnotus mamiraua (122 specimens, 33
244 mm). Bolivia: Beni: Rio Madeira,
Rio Beni, Tributary to Lago Tumi, 26 km SSW Riberalta, 10°59'S, 66°05'W, AUM 23644
(1, 154).
Brazil: Amazonas: Rio Japurá, Ilha da Arauacá, Município Maraã, approx.
02°04'S, 65°10'W, INPA (uncat.) (1, 121); Rio Solimões, Ilha da Marchantaria, Município
Manaus, approx. 03°06'S, 60°01'W, INPA 13609 (1, 46); Rio Purus, Sacado da Santa
16 © 2003 Magnolia Press
Luzia, 04°42.3'S, 62°22.4'W, INPA 17177 (1, 146); Rio Solimões-Japurá confluence,
Mamira Sustainable Development Reserve (MSDR), Lago Periquito Redondo,
03º05.00'S, 64°46.57'W, INPA 18392 (1, 210); INPA 18393 (1, 181), INPA 18401 (2, 178
205); MSDR, Cano do Lago Arauaé, 03º03.82'S, 64º50.08'W, INPA 18394 (1, 234);
MSDR, Lago Araçazinho, 02º59.27'S, 64º51.46'W, INPA 18395 (1, 165), INPA 18408 (3,
243); MSDR, Cano do Lago Sapucaia, 03º04.11'S, 64°48.53'W, INPA 18396 (25, 33
210), INPA 18397 (1, 192); MSDR, Cano do Lago Rato, 03º02.97'S, 64º51.52'W, INPA
18398 (3, 207
225); MSDR, Ressaca da Vila Alencar, 03º07.70'S, 64°48.03'W, INPA
18399 (1, 57), INPA 18418 (1, 160); MSDR, Jarauá lake system, Ressaca Caetono,
02º50.22'S, 64º55.79'W, INPA 18400 (2, 75-86); MSDR, Lago Promessa, 03º04.38S,
64°46.97'W, INPA 18403 (1, 160); MSDR, Lago Geraldo, 03º06.95'S, 64°49.16'W, INPA
18404 (2, 194
194); MSDR, Lago Curuça Comprido, 03º05.50'S, 64°48.98'W, INPA
18405 (1, 227); MSDR, Lago Miratinin, 03º04.61'S, 64°50.28'W, INPA 18406 (1, 121);
MSDR, Lago Promessinha, 03º04.83S, 64°47.13'W, INPA 18407 (4, 132
183); MSDR,
Lago Tracajá, 03º05.67'S, 64°46.57'W, INPA 18409 (1, 100); MSDR, Lago Matá-Matá,
03º06.68'S, 64°47.36'W, INPA 18410 (6, 182
222), INPA 18415 (1, 203); MSDR, Paraná
do Apara, 03º02.52'S, 64º51.01'W, INPA 18411 (2, 212
215); MSDR, Lago Secretaria,
03º06.74'S, 64°48.02'W, INPA 18412 (1, 204), INPA 18413 (2, 163
215), INPA 18414 (1,
217); INPA 18416 (5, 95
244), INPA 18419 (1, 205), INPA 18421 (1, 215); MSDR, Cano
do Lago Mamirauá, 03º06.62'S, 64°47.81'W, INPA 18417 (3, 50
217); MSDR, Lago
Apolônia, 03º07.35'S, 64°49.82'W, INPA 18420 (1, 177); MSDR, Cano do Lago Sapucaia,
03º04.11'S, 64°48.53'W, MCP 1131 (2, 180
187), MCP 29805 (35, 3950); Rio Amazonas
at Manaus, Município Manaus, approx. 03°07'S, 60°01'W, MCZ 78146 (1, 198). All local-
ities from MSDR in the municipalities Alvarães.
Pará: Lago Uruirá, Município, approx.
01°45'S, 55°52'W, MUSM 0536 (1, 146).
Peru: Madre de Dios: Rio Madre de Dios,
Tambopata, L. Copamanu, approx. 12°44'S, 69°11'W, MUSM 16711 (1, 180); Rio Madre
de Dios, Rio de Los Amigos, approx. 12°35'S, 70°04'W, MUSM 19993 (2, 133
Gymnotus inaequilabiatus (51 specimens, 77
998 mm). Argentina: Rio Bermejo,
26°52'0"S, 58°22'59"W, UF 125973 (6, 191
241). Brazil: Rio Grande do Sul: Rio Uru-
guai, Santana Velha, Uruguaina, 29°45'0"S, 57°4'59"W, MCP 6956 (1 [2], 602); Rio
Maquine, Uruguaina, 29°44'0"S, 50°7'59"W, MCP 7155 (1, 245).
o Paulo: Rio
Paraná, Porto Primavera, 22°30'0"S, 53°0'59"W, MZUSP 46001 (1, 998); Rio Capivara,
trib. of Rio Paranapanema, 22°47'59"S, 50°58'0"W, MZUSP 51268 (1, 270). Paraibo do
Sul, Jacarei, 23°19'0"S, 45°58'0"W, MZUSP 51667 (1).
Paraguay: Alto Paraná: Puerto
Max, 22°40'59"S, 57°44'0"W, BMNH 1910.5.26.50 (1); Rio Paraguay, Alto Paraguay,
Bahia Negra, 58°0'0"W, 20°0'0"S, NRM 22850 (1, 80); Concepcion, Estancia Laguna
Negra, 23°4'0"S, 57°7'0"W, NRM 23121 (1, 275); Rio Paraguay, Alto Paraguay, Riacho
Mosquito, 22°12'0"S, 57°57'0"W, NRM 43303 (1, 83), NRM 43790 (1, 165); Rio Parana,
Rio Guyraugua, Caaguazu, 25°27'0"S, 56°0'59"W, NRM 45257 (1, 118); Alto Paraná,
Pedro Juan Caballero, 22°34'0"S, 55°37'0"W, UMMZ 206703 (4, 113
280); Alto Paraná,
© 2003 Magnolia Press 17
near Pto. Stroessner, Arroyo Venecia, 25°34'0"S, 54°49'59"W, UMMZ 206939 (1, 154);
Rio Paraná, Rio Confuso, Presidente Hayes, Estancia la Golondrina, approx. 25°8'59"S,
57°33'59"W, UMMZ 206971 (2, 255
261), UMMZ 207096 (3, 132210), UMMZ 215183
(1, 170), UMMZ 216576 (1, 322); Rio Paraná, Rio Confuso, Presidente Hayes, 34 km NW
Pt. Remaro bridge, approx. 25°8'59"S, 57°33'59"W, UMMZ 207025 (17, 215
235); Rio
Paraná, Rio Confuso, Presidente Hayes, Rio Pilcomayo near Puerto Falcon, 25°15'0"S,
57°43'00"W, UMMZ 207564 (2, 220
242); Rio Paraná, Rio Confuso, Presidente Hayes,
Riachuelo Pilco, 26°6'0"S, 56°14'0"W, UMMZ 207619 (1, 144); Alto Paraná, Arroyo
Peguajho, Ypan, 25°27'0"S, 57°31'59"W, UMMZ 207760 (2, 77
We acknowledge the following for access to specimens and information; J. Armbruster
(AUM); O. Crimmen, D. Siebert (BMNH); R. Robins (UF); B. Chernoff, M. Rogers
(FMNH); L. Rapp Py-Daniel, J. Zuanon (INPA); R. Reis (MCP); K. Hartel (MCZ); H.
Ortega (MUSM); M. de Pinna, J. Lima De Figueiredo, O. Oyakawa, (MZUSP); E. Ahl-
ander, S. Kullander (NRM); W. Fink, D. Nelson (UMMZ); M. Hagedorn, S. Jewett, L.
Parenti, R. Vari (USNM). We acknowledge the Neodat project (NSF/AID DEB grant 90-
24797) for collection information. Thanks to H. Ortega and L. Verdi for field assistance,
and to K. Aviles, R. Co, J. Hill, N. Kook and D. Thorsen for laboratory assistance. This
research was conducted in collaboration with Universidade Nacional de la Amazonia
Peruana (UNAP) and funded by National Science Foundation (NSF-DEB 0084704,
0102593, 0138633), University of Florida Research Opportunity Fund, and Florida
Museum of Natural History.
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formes) from an Upper Amazonian floodplain, with descriptions of electric organ discharges
and ecology. Ichthyological Exploration of Freshwaters, 12 (3), 241–266.
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Teleostei: Gymnotoidei) from Middle America, with a key to species of Gymnotus. Proceed-
ings of the Biological Society of Washington, 108 (4), 662–678.
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Freshwaters, 13 (2), 185–192.
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from Eastern Brazil (Teleostei: Ostariophysi: Gymnotiformes), with evidence for the mono-
phyly of the genus. Copeia, 1996 (4), 937–944.
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for demonstration of cartilage. Stain Technology, 52 (4), 229–232.
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... The weakly electric Neotropical fish genus Gymnotus has been the subject of several taxonomic studies in recent years (Mago-Leccia 1994;Albert & Miller 1995;Campos da Paz 1996;Campos da Paz & Costa 1996;Fernandes-Matioli et al.,1998a;1998b;Albert et al., 1999;Campos da Paz 2000;Fernandes-Matioli et al., 2000;Albert 2001;Albert & Crampton 2001;Fernandes-Matioli & Almeida-Toledo 2001;Campos da Paz 2002;Albert & Crampton 2003;Campos da Paz 2003). Until recently Gymnotus was recognized as the only genus in the family Gymnotidae. ...
... Comparative materials have been examined from museum collections and reported in: (Albert et al., 1999;Albert 2001;Albert & Crampton 2001;Albert & Crampton 2003;Crampton et al., 2003). Measurements and counts are abbreviated in Tables 2 and 3 respectively, and follow Albert & Crampton (2003). ...
... Comparative materials have been examined from museum collections and reported in: (Albert et al., 1999;Albert 2001;Albert & Crampton 2001;Albert & Crampton 2003;Crampton et al., 2003). Measurements and counts are abbreviated in Tables 2 and 3 respectively, and follow Albert & Crampton (2003). ...
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A new species of Neotropical electric fish, Gymnotus ardilai, is described from the R o de Oro near Bucaramanga in the Rio Magdalena Basin. Gymnotus ardilai is distinguishable from all congeners by the following combination of characters: 1, a clear patch at the caudal end of the anal fin; 2, two laterosensory canal pores (from the preopercular-mandibular series) in the dorso-posterior portion of the preopercle; 3, progressive loss of alternating dark and light pigment bands with the size; 4, a long head (10.2 11.2 % total length); 5, many (9 10) scales over anal fin pterygiophores; 6, few (47 48) pored lateral-line scales to first ramus; 7, low (84 n = 1) total number of pored lateral-line scales ; and, 8, relatively large eye (orbital diameter 8.5 9.0 % HL). Gymnotus ardilai is the first record of the genus from the Magdalena Basin and represents a unique record of Gymnotiformes from over 800 meters above sea level.
... Bibliografía consultada: Crampton et al., 2003;Galvis et al., 2007;Ortega et al., 2012;Sánchez et al., 2011;Froese & Pauly, 2019. III I II I I I II II I I I I I II I III I II II II I I I II II II I II III I I I II I II I I I II III I II I I II I I II I I II I I II I III I I I IIII I I I I I I III I II I I I II I I I I I IIII IIII I I IIII I I I II IIIIII I I I I I I I II II II II I IIII I II I I I I II I I II I I II II I II II I I II I III IIII I I I I III I II II I II II I I I I II II I II I I I I II II IIII II I I I II I I I I I II I I I IIII I I II I I I I II II I I II IIII I I IIII I I IIII II II I I I II I I IIII I I I II I II II II I II I I I II I I I I II I I I I I I I II I I I II I II I III II I II I III I I I I II I I I I I I I I I I I II I I III III II II II II I I I I II III I I I I I I I I I I I I I I I II I I I I I II IIIII II I I IIIII II I III II IIIII I II I I I II II I I III III II II I II I I I II I III II I I I I II I I I I II I I I FAMILIA G MNOTIDAE ymnot s a ari Albert, Crampton & Hagedorn 2003 Nombre com n: Macana cebra. ...
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El libro profundiza en el conocimiento de 212 especies de peces ornamentales que habitan las aguas de la Amazonia peruana. Para cada una de ellas, no solo se abordan los aspectos taxonómicos, ecológicos y biológicos, sino que también se especifican las zonas geográficas donde fueron registradas, así como los datos de comercialización, nacional e internacional del 2000 al 2017. Se espera que el conocimiento de la biología, ecología, sistemática y genética de las especies amazónicas en las que se focaliza este libro, contribuyan al desarrollo de una verdadera política de manejo sostenido de las especies, incluyendo la protección de los ecosistemas amazónicos. Esto posibilitaría que en el futuro las limitaciones o prohibiciones de colectas de peces ornamentales en su medio natural sean compensadas con el desarrollo de una piscicultura ornamental sostenible. link descarga:
... Here, we present a biogeographical analysis that focuses on To provide geographical and phylogenetic context, we also included samples of G. carapo from other parts of South America, as well as samples of several closely related species (Appendix S1 in Supporting Information). Crampton, Lovejoy, and Albert (2003) defined G. carapo sensu stricto and we included samples from sev- Crampton, Rodr ıguez-Catt aneo, Lovejoy, & Caputi, 2013;Lovejoy, Lester, Crampton, Marques, & Albert, 2010;Maxime, 2013). We included representatives of as many of these species as possible (generally corresponding to members of "G. ...
The Guiana Shield region exhibits extraordinary topography that includes sheer, flat-topped mountains (tepuis) atop an upland platform. Rivers of the eastern Pakaraima Mountains descend to Atlantic coastal lowlands, often traversing spectacular rapids and waterfalls. For fish species distributed in both uplands and lowlands, it is unclear whether these rapids and waterfalls present population or biogeographical boundaries. We sought to test this using the geographically widespread banded-electric knifefish (Gymnotus carapo) as a model. The Guiana Shield region of South America. We sampled 60 Gymnotus carapo specimens from the Guiana Shield region, and 75 G. carapo and closely related species from other parts of South America. We sequenced the mitochondrial cytochrome b gene and an intron from the nuclear S7 ribosomal protein gene, and used maximum likelihood and Bayesian tree-building approaches to generate phylogenetic trees of haplotypes. Haplotype sharing is minimal between populations separated by elevational barriers. We found evidence for two main haplotype clades in the Guiana Shield: one distributed in Atlantic coastal regions that includes most lowland samples, and one inland that includes most upland samples. Inland Guiana samples are more closely related to samples from the Amazon basin than to those of Atlantic coastal regions. A single sample from Tafelberg tepui in Suriname was most closely related to the Atlantic coastal lineages. Riverine barriers that result from steep elevational gradients in the Guiana Shield inhibit gene flow between uplands and lowlands, even for a widely distributed species. Biogeographical relationships of Guiana Shield G. carapo are complex, with most upland lineages showing affinities to the Amazon basin, rather than to nearby lowland drainages of the Atlantic coast.
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The diversity of gymnotid electric fishes has been intensely studied over the past 25 years, with 35 species named since 1994, compared to 11 species in the previous 236 years. Substantial effort has also been applied in recent years to documenting gymnotid interrelationships , with seven systematic studies published using morphological and molecular datasets. Nevertheless, until now, all gymnotids have been assigned to one of just two supraspecific taxa, the subfamily Electrophorinae with one genus Electrophorus and three valid species and the subfamily Gymnotine also with one genus Gymnotus and 43 valid species. This simple classification has obscured the substantial phenotypic and lineage diversity within the subfamily Gymnotine and hampered ecological and evolutionary studies of gymnotid biology. Here we present the most well-resolved and taxon-complete phylogeny of the Gymnotidae to date, including materials from all but one of the valid species. This phy-logeny was constructed using a five-gene molecular dataset and a 115-character morphological dataset, enabling the inclusion of several species for which molecular data are still lacking. This phylogeny was time-calibrated using biogeographical priors in the absence of a fossil record. The tree topology is similar to those of previous studies, recovering all the major clades previously recognized with informal names. We propose a new gymnotid classification including two subfamilies (Electrophorinae and Gymnotinae) and six subgenera within the genus Gymnotus. Each subgenus exhibits a distinctive biogeographic distribution, within which most species have allopatric distributions and the subgenera are diverged from one another by an estimated 5-35 million years. We further provide robust taxonomic diagnoses , descriptions and identification keys to all gymnotid subgenera and all but four species. This new taxonomy more equitably partitions species diversity among supra-specific taxa, employing the previously vacant subgenus and subfamily ranks. This new taxonomy renders known gymnotid diversity more accessible to study by highlighting the deep divergences (chronological, geographical, genetic and morphological) among its several clades.
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Banded Knifefishes (Gymnotus, Gymnotidae) comprise the most species-rich genus of Neotropical electric fishes, with 41 species currently described from throughout the humid Neotropics, from Mexico to Argentina. Despite substantial alpha -taxonomic work in recent years, the diversity of Gymnotus in some regions remains poorly understood. Here we describe the Gymnotus fauna of the Upper Madeira basin of Bolivia and Peru from examination of more than 240 adult specimens. Species are delimited and described using body proportions (traditional morphometrics), fin-ray, squamation and laterosensory-pore counts (meristics), quantitative shape differences (geometric morphometrics), osteological traits, and color patterns. Comparisons of standardized linear measures as well as multivariate statistical methods validate the presence in the Upper Madeira basin of three previously described species, two with widespread geographic distributions throughout Greater Amazonia (G. carapo and G. coropinae), and one (G. chaviro) endemic to southwestern Amazonia. We also diagnose and describe two new species that are endemic to the Upper Madeira basin: G. eyra n. sp., morphologically most similar to G. mamiraua from lowland Amazonia, and G. riberalta n. sp., morphologically most similar to G. pantanal from the Paraguay-Paraná basin. The five Gymnotus species from the Upper Madeira basin are not monophyletic, each species being more closely related to a different species from another region; i.e. the Gymnotus species from the Upper Madeira represents a polyphyletic assemblage. These descriptions to 43 the number of valid Gymnotus species.
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Banded Knifefishes (Gymnotus, Gymnotidae) comprise the most species-rich, ecologically tolerant (eurytopic), and geo- graphically widespread genus of Neotropical electric fishes (Gymnotiformes), with 40 valid species occupying most hab- itats and regions throughout the humid Neotropics. Despite substantial alpha-taxonomic work in recent years, parts of the genus remain characterized by taxonomic confusion. Here we describe and delimit species of the G. carapo and G. tigre clades from the southern Neotropics, using body proportions (caliper-based morphometrics), fin-ray, scale and laterosen- sory-pore counts (meristics), quantitative shape differences (geometric morphometrics), osteology, color patterns and electric organ discharges. We report these data from 174 Gymnotus specimens collected from 100 localities throughout the southern Neotropics, and delimit species boundaries in a multivariate statistical framework. We find six species of the G. carapo clade (G. carapo australis, G. cuia n. sp., G. chimarrao, G. omarorum, G. pantanal, and G. sylvius), and two species of the G. tigre clade (G. inaequilabiatus and G. paraguensis) in the southern Neotropics. The new species G. cuia is readily distinguished from the morphologically similar and broadly sympatric G. c. australis by a shorter head and deep- er head and body, and from the morphologically similar and sympatric G. omarorum by fewer lateral-line ventral rami and fewer pored lateral-line scales anterior to the first ventral ramus. We also review the geographic distributions of all eight species of the G. carapo and G. tigre clades in the southern Neotropics, showing that G. cuia is the most widespread species in the region. These results affirm the importance of understanding the structure of variation within and between species, both geographic and ontogenetic, in delimiting species boundaries.
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The banded knife fish Gymnotus carapo is among the most widely distributed, broadly adapted (eurytopic), and phenotypically variable fish species in South America, with a geographic range of about 14 million km2, from the Llanos of Ven- ezuela to the Pampas of northern Argentina. Here we assess the structure of phenotypic variation in G. carapo across this vast range from a study of 486 specimens representing the G.carapo clade, including 175 specimens of G.carapo collected from across the continental platform. We use multivariate statistics to quantify phenotypic differences within and among subspecies and species in aspects of pigmentation, caliper-based morphometrics, geometric morphometrics, meristics, and osteology. Our results demonstrate significant, but not diagnostic, differences among specimens representing seven new subspecies: G. c. australis from the La Plata (Paraná-Paraguay) basin, G. c. caatingaensis from the Parnaíba basin in the Brazilian state of Piauí, G. c. carapo from Suriname and French Guiana, G. c. madeirensis from the upper Madeira basin, G. c. occidentalis from the western Amazon, Negro, and Essequibo basins, G. c. orientalis from the eastern Amazon, Tocantins and Trombetas basins, and G. c. septentrionalis from the Orinoco basin and Trinidad Island. These results support the use of the subspecies, but not the species, rank to recognize and name these regionally delimited taxonomic entities.
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A list of all valid names of species of Neotropical electric fishes (Gymnotiformes) is presented herein. The list is arranged by family and genus and includes all available synonyms. The list is comprehensive through 2016 and includes 240 valid species distributed among 34 genera and five families, including one monotypic genus known only from the fossil record. The presented classification reflects recently published interpretations about the validity of the included names which, in general, are widely accepted. When the validity of a particular name is disputed in recent literature, we followed one of the published interpretations and provide relevant information on the alternate interpretation(s) in the remarks section of that name. Synonymies of some names need to be considered tentative, inasmuch as the types underlying those names are either absent or appear to be based on more than one taxon. First reviser actions (e.g., lectotype and neotype designations, resolution of simultaneous synonyms, etc.) are reported and include erroneous subsequent attempts at problem resolutions. Herein, we include one new first reviser action by selecting Gymnotus aequilabiatus Humboldt, 1805, as type species of Sternopygus because previous attempts to select a type did not follow the provisions of the Code of Zoological Nomenclature.
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Some field studies have attempted to describe how the physical environment of gymnotiform fishes may have influenced the evolutionary design of their electric signals. However, most of these studies either focused on low-diversity communities in a small range of habitats or, alternatively, failed to adequately define habitat preferences. This paper aims to describe correlations between electric signal structure and the ecology and lifestyle of gymnotiform fishes in a study area that embraces not only all the major aquatic habitats of the lowland and Amazon basin, but also all the major gymnotiform taxa. The species diversity, electric signal diversity, habitat preferences and general lifestyles of an assemblage of 64 species of gymnotoids from the Tefé region of the Brazilian Amazon are described. The following relationships between elecric signal structured ecology or lifestyle were observed: (1) There are strong correlations between electric organ discharge (EOD) repetition rate and both (a) the flow regime of the habitat, and (b) the toraging mode of gymnotoids. These correlations are presumably related to the temporal acuity required for efficient foraging. (2) There is a tendency tor the adults of tone-type species to forage in open, geometrically simple substrates. In contrast, most pulse-type species tend to forage within dense, geometrically complex substrates. This may be related to the expected superiority of pulse-type signals in detecting wide ranges of natural capacitances. (3) Although short pulse-type EODs are expected to differ rom long pulse-type EODs in their respective abilities to resolve small versus large natural capacitances, there are no obvious correlations between the EOD duration of pulse-type fishes and the substrate architecture of their preferred habitat. Instead, social, selective forces related to minimising sensory interference and avoiding hybridisation appear to represent more important influences on the EOD diversity of sympatric congeners. (4) Species with tone-type discharges tend to be excluded from habitats that are subject to low dissolved oxygen levels. This may in part be related to energetic handicaps imposed by the inability of tone-type gymnotoids to lower their EOD repetition rate and/or to temporarily switch off the EOD during periods of oxygen stress.
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A new species of Gymnotus is described from Atlantic and Rio Parana drainages of Sao Paulo State, Brazil. The new species inhabits small creeks with murky, slowly moving water, and grows to about 300 mm in length. The new species is diagnosed by the presence of 21 or 22 pairs of obliquely oriented dark pigment bands with wavy margins in which the dark bands are more narrow than the white interband regions. The new species also differs from other members of Gymnotus in features of body proportion, electric organ discharge (EOD), karyotype, and microsattelite DNA. The color pattern of the new species most closely resembles the sympatric G. Inaequilabiatus. Together, these two species share three features with G. carapo, the type species of the genus: a relatively deep body, wavy margins of the pigment bands, and a clear patch at the caudal end of the anal fin. Based on these three characters specimens collected from as far apart as Argentina and Colombia have been referred to the nominal species 'G. carapo,' despite sizable variation in color pattern and body proportions. A result of this coarse taxonomy is that 'G. carapo' is thought to have the most extensive geographical range of any gymnotiform species. Identifying the new species from within this range documents a previously overlooked component of diversity in the group. The data also demonstrate that genetic differences accompany morphological variation in a widespread assemblage of Neotropical fishes.
Gymnotus bahianus sp. nov. is described from the Rio Almada basin, near Ilhéus, Bahia State, Brazil. It is currently known only from that area, representing the third record of a gymnotid species in eastern Brazilian coastal plain basins, north of the Rio Doce basin, Espírito Santo State. Gymnotus bahianus shares with G. cylindricus LaMonte, G. inaequilabiatus (Valenciennes), and G. pantherinus (Steindachner), a pattern of small dark rounded spots over the body, which distinguish these species from their congeners. The new species is further distinguished by a unique combination of morphological features, including depth of the body and head, length of the head, pectoral fin and maxillary bone, and the number of perforated scales along lateral line. The phylogenetic relationships of the new species are still unknown. New evidence for the monophyly of Gymnotus is presented. /// Gymnotus bahianus sp. nov. é descrita da bacia do rio Almada, vizinhanças de Ilhéus, Estado da Bahia, Brasil. Atualmente, é conhecida apenas daquelas áreas, consistindo o terceiro registro de uma espécie de Gymnotidae para as bacias costeiras do leste do Brasil, ao norte da bacia do rio Doce, Estado do Espírito Santo. Gymnotus bahianus é similar a G. cylindricus LaMonte, G. inaequilabiatus (Valenciennes) e G. pantherinus (Steindachner), diferindo das demais espécies do gênero por seu padrão de colorido, o qual consiste de pequenas manchas escuras e arredondadas distribuídas sobre o corpo. A nova espície é também distinta com base numa combinação única de características morfológicas, compreendendo as alturas do corpo e da cabeça, comprimentos da cabeça, nadadeira peitoral e osso maxilar, e número de escamas perfuradas da linha lateral. As relaçães filogenéticas de G. bahianus são ainda desconhecidas. Nova evidência para o monofiletismo de Gymnotus é apresentada.
A detailed comparison of the original descriptions of Rhamphichthys cingulatus Brind, 1935, and Gymnotus coatesi LaMonte, 1935, including study of the holotype of this latter species, leads to the conclusion that these two names refer to the same species. Based on currently available information on the publication dates of these specific names, Rhamphichthys cingulatus is regarded as a subjective junior synonym of Gymnotus coatesi. Information in Brind (1935) indicates that the specimens available for his description of R. cingulatus and the holotype of G. coatesi were part of the same original sample and were collected near, or in, the rio Moju, Amazon basin, Pará, Brazil. Uma comparação detalhada entre as descrições originais de Rhamphichthys cingulatus Brind, 1935, e Gymnotus coatesi LaMonte, 1935, incluindo o estudo do holótipo desta última espécie, leva à conclusão de que estes dois nomes referem-se a uma mesma espécie. Com base em informações atualmente disponíveis relativas às datas de publicação destes nomes específicos, Rhamphichthys cingulatus é considerada um sinônimo júnior subjetivo de Gymnotus coatesi. Informações no trabalho de Brind (1935) indicam que os exemplares disponíveis para sua descrição de R. cingulatus e o holótipo de G. coatesi eram parte de uma mesma amostragem original, tendo sido coletados nas proximidades do, ou no, rio Moju (bacia Amazônica, Pará, Brasil).
Gymnotus cylindricus LaMonte, a poorly studied Central American electric fish primarily observed in the Rio Motagua basin (Guatemala) and north-western Honduras, is redescribed in detail. A clear diagnosis of this species is provided, with new information on overall morphology, osteology, and colour pattern. In a separate section, comments on character ambiguity within the Ostariophysi are made, which led to a reinterpretation of seven homoplastic characters proposed by Fink & Fink (1981) in their work on interrelationships among five major lineages of the superorder. Although the topology of their cladogram remains unchanged, the present view is that alternative explanations regarding evolution of those characters are possible, and the new ones here offered agree with initial hypotheses of primary homologies.
Estimates of the density, biomass and species diversity of fish from floating meadow and flooded forest habitats suggest that gymnotiform fish constitute an important component of Amazonian flood plain fish faunas. Electric eels, Electrophorus electricus are unexpectedly abundant within Varzea forest.