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A New Species of Corydoradinae Catfish (Ostariophysi: Siluriformes:
Callichthyidae) from Rio Solimo˜es Basin, Brazil
Marcelo R. Britto
1
, Wolmar B. Wosiacki
2
, and Luciano F. A. Montag
3
A new species of Corydoras from the Rio Urucu basin, a right-bank tributary of the Rio Solimo˜es is described. The new
species shares a distinctive pigmentation pattern with Corydoras arcuatus,C. gracilis, and C. narcissus, composed of a
uniform light ground color on the body, and a dark, arched stripe from tip of snout to caudal-fin base along the upper
portion of the dorsolateral body plates. The new species is readily distinguished from these congeners by the absence of
a continuation of the arc-like stripe onto the snout. It also differs from Corydoras gracilis and C. narcissus by the posterior
part of the arc-stripe reaching the base of the lower caudal-fin rays, and from C. arcuatus and C. narcissus by the
distinctly rounded profile of the snout in lateral view, a greater preadipose distance, and the position of the posterior
limit of the cleithrum. Despite the general resemblance, investigation about the position of the new species in light of
previous phylogenetic hypotheses concerning this subfamily indicates that the arc-striped coloration pattern was
independently acquired.
Uma nova espe´ cie de Corydoras da bacia do Rio Urucu, um afluente da margem direita do Rio Solimo˜es, e´ descrita. A
nova espe´ cie compartilha um padra˜o de pigmentac¸a˜o com Corydoras arcuatus,C. gracilis,eC. narcissus, composto de
colorido claro e uma faixa escura em arco da extremidade do focinho a base da nadadeira caudal atrave´ s da porc¸a˜o
superior das placas dorsolaterais do corpo. A nova espe´cie e´ prontamente distinta destas congeˆneres pela auseˆncia de
continuac¸a˜o da faixa se estendendo ate´ o focinho. Tambe´ m se distingue de Corydoras gracilis eC. narcissus pela
extremidade posterior da faixa em arco alcanc¸ar a base dos raios inferiores da nadadeira caudal, e de C. arcuatus eC.
narcissus pelo perfil do focinho distintamente arredondado em vista lateral, pela maior distaˆ ncia pre´ -adiposa, e pela
posic¸a˜o do limite posterior do cleitro. Apesar da semelhanc¸a, investigac¸o˜ es sobre a posic¸a˜o da nova espe´cie a luz de
hipo´ teses filogene´ ticas pre´ vias sobre a subfamı´lia, indicam que o padra˜o de colorido com uma faixa em arco foi
adquirido independentemente.
THE genus Corydoras is the most speciose genus of
catfishes, and currently includes more than 150
species (Reis, 2003; Ferraris, 2007). The species of
Corydoras are widely distributed throughout cis-Andean South
America in small streams, along river margins, and in pools.
Sixty-five species of Corydoras are known at present from
the rivers of the western Amazon upriver of the confluence
of the Rio Solimo˜ es and Rio Negro (Reis, 2003; Ferraris,
2007), and many other species remain undescribed (Fuller
and Evers, 2005). Recently during ichthyological surveys in
the Rio Urucu system, a right-bank tributary of Rio Solimo˜ es,
specimens of a species of Corydoras were collected that
appeared to be similar to several species that have an arc-like
stripe (i.e., C. arcuatus,C. narcissus,andC. gracilis).
Examination of the material revealed that this is a new
species of Corydoras, which is described herein.
MATERIALS AND METHODS
Morphometric and meristic data were taken following Reis
(1997). Length of the ossified portion of the pectoral spine
was measured from the point of articulation of the spine to
the pectoral girdle to the distal tip of the spine. Measure-
ments were taken with calipers to 0.1 mm. Teeth and
vertebral counts were taken from cleared-and-stained (CS)
specimens prepared according to Taylor and Van Dyke
(1985). Vertebral counts include only free centra, with the
compound caudal centra (preural 1 +ural 1) counted as a
single element. Lateral plate counts include all dorsolateral
and ventrolateral plates, except for the small, irregular plates
on the caudal peduncle. In the description, numbers in
parentheses following each count represent total of speci-
mens with that value. Numbers with an asterisk represent
counts from the holotype. Nomenclature of latero-sensory
canals follows Schaefer and Aquino (2000), and that of
preopercular pores follows Schaefer (1988). Osteological
terminology follows Reis (1998), except that parieto-supra-
occipital is used instead of supraoccipital (Arratia and Gayet,
1995), compound pterotic instead of pterotic-supraclei-
thrum (Aquino and Schaefer, 2002), and scapulocoracoid
instead of coracoid (Lundberg, 1970). Homology of barbels
follows Britto and Lima (2003). Phylogenetic analyses were
performed using the character-data matrix published by
Britto (2003), including outgroup data provided in that
study, with the addition of the new species. The analysis was
performed using Hennig86 software (Farris, 1988) via the
heuristic algorithm ‘‘mhennig*’’ associated with the com-
mand ‘‘bb*’’ (‘‘branch-breaker’’). Attributes of connectivity
and ambiguity among character-states were treated in the
same way as in Britto (2003). Institutional abbreviations are
as listed at http://asih.org/codons.pdf, with the addition of
IAvH, Instituto de Investigacio´n de Recursos Biolo´ gicos
Alexander von Humboldt, Colombia.
Corydoras urucu, new species
Figure 1, Table 1
Holotype.—MPEG 14924, 27.5 mm SL, Brazil, Amazonas
State, Coari, Igarape´ da Onc¸a, Rio Urucu basin, tributary of
1
Museu Nacional/UFRJ, Setor de Ictiologia, Departamento de Vertebrados, Quinta da Boa Vista s/n, Sa˜o Cristo´va˜o, 20940-040 Rio de Janeiro,
RJ, Brazil; E-mail: mrbritto2002@yahoo.com.br. Send reprint requests to this address.
2
Museu Paraense Emı´lio Goeldi, Av. Magalha˜es Barata 376, Cx. Postal 399, 66040-170 Bele´m, PA, Brazil; E-mail: wolmar@museu-goeldi.br.
3
Universidade Federal do Para´ , Laborato´ rio de Vertebrados–Ictiologia, Instituto de Cieˆncias Biolo´gicas, Rua Augusto Correˆa 01, Guama´, Cx.
Postal 479, 66075-110 Bele´m, PA, Brazil; E-mail: lfamontag@gmail.com.
Submitted: 4 December 2008. Accepted: 18 May 2009. Associate Editor: C. J. Ferraris.
F2009 by the American Society of Ichthyologists and Herpetologists DOI: 10.1643/CI-08-228
Copeia 2009, No. 4, 684–689
Lago Coari, Rio Solimo˜es system, 4u5299.120S, 65u1893.60W,
19 November 2006, W. B. Wosiacki, L. F. A. Montag, and M.
B. Mendonc¸a.
Paratypes.—MPEG 12239, 6, 25.2–27.4 mm SL; MNRJ 32446,
4, 25.9–27.3 mm SL; all collected with holotype; MPEG
11252, 4, 22.5–25.8 mm SL (2 CS), same locality and
collectors as the holotype, 22 August 2006; MPEG 15102,
8, 20.0–23.0 mm SL, same locality as the holotype, 26 July
2008, W. B. Wosiacki, L. F. A. Montag, and C. S. Ramos.
Diagnosis.—Corydoras urucu is distinguished from all other
species of Corydoras, except for C. arcuatus,C. narcissus, and
C. gracilis, by the presence of a long, arched, dark stripe,
running parallel to the dorsal profile and extending at least
from the anterior margin of the first dorsolateral body plate
to the caudal peduncle. Corydoras urucu differs from C.
arcuatus,C. gracilis, and C. narcissus in having the arc-like
stripe terminating posterior to the orbit (vs. extending onto
snout; Fig. 2). Corydoras urucu further differs from C. arcuatus
by having fewer free vertebrae (21 vs. 27); the lateral profile
of the snout distinctly rounded (vs. nearly straight); a
greater preadipose distance (84.0–86.7%SL, vs. 82.9–83.8%
SL); and the posterior limit of the cleithrum at a vertical
through the dorsal-fin spinelet (vs. between the third and
fourth dorsal-fin rays). Corydoras urucu further differs from
C. gracilis by having fewer free vertebrae (21 vs. 27); the
arched stripe extending posteriorly to the base of the lower
caudal-fin rays (vs. reaching the base of the upper caudal-fin
rays); and the second infraorbital contacting only the
sphenotic (vs. contacting both the sphenotic and com-
pound pterotic). Corydoras urucu further differs from C.
narcissus in having the arched stripe extending posteriorly
across the lower caudal-fin rays (vs. extending over the
lower caudal-fin rays); the lateral profile of the snout
distinctly rounded (vs. nearly straight); and by minute and
weak pectoral-spine serrations (Fig. 3; vs. large and strong
serrations; Nijssen and Isbru¨cker, 1980:fig. 4c).
Description.—Morphometric data presented in Table 1. Head
compressed with convex dorsal profile (Fig. 1); roughly
triangular in dorsal view. Snout rounded. Head profile
convex from upper lip to tip of parieto-supraoccipital
expansion. Dorsal profile of body slightly convex from tip
of parieto-supraoccipital expansion to base of last dorsal-fin
Fig. 1. Corydoras urucu, MPEG 14924, holotype, 27.5 mm SL, Igarape´ da Onc¸ a, tributary of Rio Urucu, tributary of Lago Coari, Coari,
Amazonas, Brazil.
Table 1. Morphometric Data of Holotype and Paratypes of Corydoras
urucu (n522, other than n516 for maximum cleithral width).
Holotype
Paratypes
Mean Range
Standard length (mm) 27.5 24.2 20.0–27.4
Percentage of standard length
Depth of body 35.3 33.9 31.1–37.1
Predorsal distance 50.0 50.3 46.5–53.7
Prepelvic distance 46.1 47.2 44.7–51.4
Preanal distance 82.0 79.8 75.2–82.9
Preadipose distance 84.3 82.8 78.0–86.7
Length of dorsal spine 30.2 26.8 23.4–29.9
Length of pectoral spine 29.7 28.3 23.2–32.1
Length of adipose-fin spine 9.0 8.7 6.7–10.8
Depth of caudal peduncle 15.9 15.1 13.5–16.7
Dorsal to adipose distance 21.6 19.2 15.6–23.0
Length of dorsal-fin base 19.7 19.1 16.7–25.0
Maximum cleithral width 27.6 19.4 17.3–21.0
Head length 44.5 44.0 42.6–46.4
Length of maxillary barbel 18.0 13.3 8.9–17.2
Percentage of head length
Head depth 79.2 75.7 71.3–80.9
Least interorbital distance 29.4 30.9 28.9–33.3
Horizontal orbit diameter 24.3 26.0 22.8–29.0
Snout length 35.9 33.8 30.1–37.5
Least internarial distance 17.8 15.6 13.5–20.7
Britto et al.—A new corydoradine catfish 685
ray. Postdorsal-fin body profile slightly concave to base of
adipose-fin spine; straight to slightly concave from that
point to caudal-fin base. Ventral profile of body straight
from isthmus to pelvic-fin origin, slightly convex from that
point to anal-fin origin. Profile slightly concave from first
anal-fin ray to caudal-fin base. Body roughly triangular in
cross section at pectoral girdle, gradually becoming more
compressed toward caudal fin.
Eye round, located dorso-laterally on head; orbit delimit-
ed dorsally by frontal and sphenotic, ventrally by infra-
orbitals. Anterior and posterior nares proximal and only
separated by flap of skin. Anterior naris tubular. Posterior
naris close to anterodorsal margin of orbit, separated from
orbit by distance slightly smaller than naris diameter.
Mouth small, subterminal, width nearly equal to bony orbit
diameter. Maxillary barbel not reaching anteroventral limit
of gill opening. Length of maxillary barbel nearly equal to
that of outer mental barbel. Inner mental barbel fleshy.
Small rounded papillae covering entire surface of all barbels,
upper and lower lips, and isthmus. Gill membranes united
to isthmus. Four branchiostegal rays covered by thin layer of
skin; two distal branchiostegal rays united at their tips by
branchiostegal cartilage. Teeth on upper pharyngeal tooth
plate 46(1), and on fifth ceratobranchial 45(1).
Posterior area of mesethmoid, frontal, sphenotic, com-
pound pterotic, and parieto-supraoccipital visible external-
Fig. 2. Corydoras arcuatus. (A) BMNH 1939.3.3:1, holotype, 44.6 mm SL, aquarium specimen; (B) MZUSP 42512, 25.4 mm SL, Rio Tabatinga, near
Brazil–Peru border, Letı´cia, Amazonas, Brazil.
Fig. 3. Right pectoral spine of Corydoras urucu, MNRJ 32446, 26.7 mm
SL, odontodes and head of spine not depicted. Scale bar 1.0 mm.
686 Copeia 2009, No. 4
ly, all covered by thin layer of skin and bearing minute
scattered odontodes. Frontal fontanel elongate, ellipsoid,
covered by thin layer of skin; posterior portion extending
into parieto-supraoccipital. Nasal slender, curved laterally,
mesial border contacting frontal. Frontal roughly rectangu-
lar; anterior expansion in contact with nasal bone, posterior
portion contacting sphenotic and parieto-supraoccipital.
Sphenotic trapezoid in shape, contacting parieto-supraoc-
cipital dorsally, compound pterotic posteriorly, second
infraorbital ventrally. Compound pterotic roughly pipe-
shaped, with posterior expansion contacting first lateral-line
ossicle. Ventral margin of compound pterotic contacting
opercle and cleithrum. Parieto-supraoccipital quadrangular
with posterior expansion notched at its tip, sutured with
nuchal plate.
Two infraorbital bones, externally visible, covered by thin
layer of skin. First infraorbital with anterior expansion.
Second infraorbital bone contacting only sphenotic poste-
riorly. Opercle exposed, compact in shape, with smooth free
border. Preopercle externally visible, slender, and covered by
thin layer of skin.
Trunk lateral line with three laterosensory canals; two
anteriormost canals reduced to small ossicles. Last lateral-
line canal encased in second dorsolateral body plate. Lateral-
line canal entering neurocranium through compound
pterotic, splitting into three branches before entering
sphenotic: pterotic and preoperculomandibular, each with
single pore. Sensory canal continuing through compound
pterotic, entering sphenotic as temporal canal, which splits
into two branches: one branch giving rise to infraorbital
canal, other branch entering frontal through supraorbital
canal. Supraorbital canal not branched, running through
nasal bone. Epiphyseal pore opening at supraorbital main
canal. Nasal canal with single opening at each end.
Infraorbital canal running through entire second infraorbit-
al, extending to infraorbital 1 and opening into three pores.
Preoperculomandibular branch giving rise to preoperculo-
mandibular canal, which runs through entire preopercle
with three openings, leading to pores 3, 4, and 5,
respectively.
Body plates with minute odontodes restricted to posterior
margins. Nuchal plate exposed. Posterior extremity of
cleithrum along vertical through dorsal-fin spinelet. Clei-
thrum and mesial process of scapulocoracoid exposed. Body
plates not touching counterparts ventrally, leaving narrow
naked area. Dorsolateral body plates 23(2), 24*(21); ventro-
lateral body plates 21*(20), 22(1); dorsolateral body plates
along dorsal-fin base 6(6), 7*(17); dorsolateral body plates
from adipose fin to caudal-fin base 8*(20), 9(3); preadipose
platelets 3(1), 4(3), 5*(16), 6(3). Precaudal vertebrae 6, and
caudal vertebrae 15 in all cleared-and-stained specimens. Six
pairs of ribs, first pair conspicuously larger than others.
Dorsal fin roughly triangular, located just posterior to
second dorsolateral body plate. Dorsal spine shorter than
first branched ray. Anterior border of dorsal spine smooth;
posterior border with 3–18 minute serrations. Dorsal-fin
rays I,8 in all specimens. Adipose fin roughly triangular,
separated from base of last dorsal-fin ray by 7–8* dorsolateral
body plates. Anal fin roughly triangular, located just
posterior to 13
th
ventrolateral body plates, and at vertical
through anterior margin of adipose-fin spine. Anal-fin rays
ii,5,i in all specimens. Pectoral fin triangular, its origin
located just posterior to gill opening. Ossified portion of
pectoral spine shorter than first branched ray. Distal tip of
spine with minute, segmented, unossified portion. Pectoral
spine with 16–25 small serrations along entire posterior
border. Pectoral serrations more developed than those of
dorsal spine. Pectoral-fin rays I,8*(20), or I,7(3). Pelvic fin
ellipsoid, located just below first ventrolateral body plate,
and at vertical through first branched dorsal-fin ray. Pelvic-
fin rays i,5 in all specimens. Caudal fin bilobed; upper lobe
slightly longer. Principal caudal-fin rays i,6/6,i. Upper and
lower procurrent caudal-fin rays both 5. All fins with minute
odontodes scattered over all rays.
Color in alcohol.—Ground coloration of head yellowish light
brown. Scattered chromatophores over interorbital and
supraoccipital areas, but more concentrated over parieto-
supraoccipital. Diffuse narrow stripe along mid-sagittal line
over posterior expansion of parieto-supraoccipital. Scattered
chromatophores over snout and outer mental barbel.
Remaining barbels yellowish light brown. Opercle and
preopercle with several, small, scattered chromatophores
over their surfaces. Chromatophores more concentrated
over anterior half of both bones.
Ground color of trunk light brown. Large, yellowish-white
area on midregion of cleithrum surrounded by several
scattered chromatophores more concentrated on posterior
portion of cleithrum. Long, black, arched stripe from
anterodorsal margin of first dorsolateral body plate through-
out upper half of dorsal plates until base of lower caudal fin.
Chromatophores concentrated as small irregular blotches at
lower and upper portions of dorsal and ventral plates,
respectively. All fins hyaline. First dorsal-fin ray and base of
caudal-fin rays with minute, scattered chromatophores.
Scattered chromatophores over preadipose platelets and
extending to adipose spine.
Habitat and ecological notes.—All specimens of Corydoras
urucu were collected along semilentic stretches of the shore
of the Igarape´ da Onc¸a. The Igarape´ da Onc¸a is a moderately
large stream, about 15 m wide, with sand, clay, and leaves
on the bottom, in addition to emerged vegetation. It has an
average depth of 1 m during the dry season, and 4 m in the
rainy season.
Distribution.—Corydoras urucu is only known from its type
locality (Fig. 4).
Etymology.—The name ‘‘urucu’’ is taken from the type
locality, the Rio Urucu basin. Originally, the word comes
from the Tupi (‘‘uru-ku’’) for red, derived from the color of
the fruit of the ‘‘urucuzeiro’’ (Bixa orellana L.), low tree of the
family Bixacea, native from tropical America. Treated as a
noun.
DISCUSSION
Corydoras urucu was initially grouped with the arc-striped
species of Corydoras, viz. C. arcuatus,C. narcissus, and C.
gracilis, whose distributions fall within the limits of the
Western Amazonian area of endemism identified by Britto et
al. (2007). In this area, Corydoras arcuatus shows the largest
range of distribution, with records from several tributary
river basins of the Rio Solimo˜es system (e.g., Rı´o Caqueta´,
Rı´o Napo, Rio Purus, Rio Tefe´ , Rı´o Ucayali, Rı´o Yavari;
Nijssen and Isbru¨ cker, 1980, 1986; Castro, 1987; Britto,
2007; Fig. 4, circles). Moreover, populations of Corydoras
arcuatus occur syntopically with C. narcissus, and there are
Britto et al.—A new corydoradine catfish 687
records of some representatives of C. arcuatus having been
collected with the type of the latter species (Nijssen and
Isbru¨cker, 1980:498–499). Although the type-locality of
Corydoras urucu is included in the distributional range of
C. arcuatus, there are no previous records for arc-striped
Corydoras specimens either in scientific collections or even
in the aquarium literature from Rio Urucu and Lago Coari.
Despite Corydoras urucu having been promptly distin-
guished from C. arcuatus as shown in the diagnosis and
discussion below, there is some resemblance between the
new taxon and juveniles of the latter species at first
inspection. Small specimens of Corydoras arcuatus within
the size range of C. urucu (20.0–27.0 mm) superficially
resemble adults of the latter, but differ nonetheless in the
characters listed in the diagnosis. Furthermore, juveniles of
C. arcuatus that are shorter than this size range do not show
the snout portion of the arc stripe, and the body stripe is
broken into several irregular, dark blotches (Fuller, 2001:38–
39). Also, specimens of Corydoras arcuatus that are up to this
size range show dorsolateral body plates not touching their
counterparts, leaving a median groove between the last
dorsal-fin ray and the first preadipose platelet (vs. dorsolat-
eral body plates touching their counterparts in C. urucu).
This kind of difference was already reported between other
species of Corydoras (Britto and Lima, 2003). Moreover,
Corydoras arcuatus reaches a body size greater than C. urucu.
Corydoras urucu was recovered in the phylogenetic analysis
in a clade distinct from the other included arc-striped
species (i.e., C. arcuatus and C. gracilis;C. narcissus is only
known from its holotype, ZMA 115.178), which further
supports the observation in Britto (2003) that this distinc-
tive color pattern arose more than once within Corydoras.
Nijssen and Isbru¨ cker (1980) already suggested convergence
of an arc-striped color pattern in the original description of
Corydoras narcissus. Both authors speculated that Corydoras
narcissus could be closer to C. acutus than to C. arcuatus.
Besides, the arc-stripe-bearing species also display differenc-
es concerning extension of the stripe, as cited in the
diagnosis.
As reported in the diagnosis, Corydoras urucu exhibits a set
of characters that readily distinguishes it from C. arcuatus,C.
narcissus, and C. gracilis. In addition, there are several
osteological character-states, shared in different levels with
other species of Corydoras, which recover C. urucu apart from
other arc-striped Corydoras. This evidence refers to structural
complexes examined in Britto (2003) like neurocranium
(characters 1, 5, 7, and 12), infraorbitals (characters 17 and
18), gill arches (characters 22, 23, and 28), suspensorium
and mandibular arch (characters 33 and 39), axial skeleton
(characters 51), anal fin (characters 59), and pelvic girdle
(characters 69 and 70). Although not exclusive to Corydoras
urucu, some of these conditions deserve comments concern-
ing their differences among arc-striped species of Corydoras.
Among that assemblage of character-states, the short
anterior portion of the mesethmoid (character 1) could be
related to the rounded snout shape in C. urucu. Although
Corydoras arcuatus and C. narcissus are set apart from each
other by the length of the snout (Nijssen and Isbru¨ cker,
1980), the feature stated above concerns the shape of the
snout, not necessarily its length. Accordingly, C. arcuatus
shows a short snout but straight in shape (Fig. 2). The
slender shape of the complex vertebra in Corydoras urucu
(character 12; shared with C. gracilis) could also be related
with some morphometric component, although it was not
sensitive to the measurements taken herein.
Although the evidence assigns the non-monophyly of an
arc-striped group of Corydoras, it is premature to pinpoint
the sister-group of Corydoras urucu.Theinclusionof
Corydoras urucu in Britto’s (2003) data matrix recovered it
in a large polytomy, outside of clade VIII in that study (a
group composed of C. arcuatus and C. gracilis, among other
species of Corydoras). Nevertheless, such evidence contrasts
with those hypotheses of sister-group relationships among
corydoradine catfishes corroborated by unique acquisitions
of character-state conditions of coloration (e.g., Corydoras
hastatus/C. pygmaeus; Schaefer et al., 1989; Britto, 2003;
Corydoras ortegai/C. panda/C. tukano/C. weitzmani; Britto et
al., 2007). The contrasting examples of the occurrence of
both well-corroborated monophyletic groups within Cor-
ydoras sharing a similar color pattern, on one hand, and
highly homoplastic color patterns, as the species of
Corydoras sharing an arc-striped color pattern, serve as a
warning about the complexity of the evolution in the genus.
MATERIAL EXAMINED
A list of the comparative material is available in Britto and
Castro (2002) and Britto (2003). In addition, the following
material was studied:
Corydoras arcuatus: BMNH 1939.3.3.1 (holotype); FMNH
94678, 21; IAvH-P 3797, 1; IAvH-P 5958, 2; NRM 13396, 4;
USNM 317900, 4, 2 CS.
C. gracilis: INPA 7759, 5, 2 CS; MPEG 9260, 2; MPEG 9278, 2.
C. rabauti: MPEG 3244, 1.
ACKNOWLEDGMENTS
We thank J. Maldonado-Ocampo (IAvH), O. Oyakawa, and
F. Lima (MZUSP) for the loan of specimens, and J. Maclaine
Fig. 4. Map of northern South America, showing the distribution of
Corydoras urucu (square in inset), C. arcuatus (circle), C. gracilis
(triangle), and C. narcissus (asterisk). Inset: detail of Rio Urucu basin
showing the type locality of Corydoras urucu.
688 Copeia 2009, No. 4
(BMNH) for kind reception at that institution. P. Willink
(FMNH) kindly provided photographs and radiographs of
Corydoras arcuatus. W. Wosiacki and L. Montag received
financial support from Financiadora de Estudos e Projetos
(FINEP), and logistical support from Petrobras (Rede CT-
Petro, PT1). The Programa de Pesquisa em Biodiversidade
(PPBio) of the Ministe´ rio da Cieˆncia e Tecnologia (MCT)
Brazilian government and CNPq (PCI fellowships) supported
the trip of M. Britto to Bele´ m. M. Mendonc¸a assisted in the
ichthyological surveys. Specimens of Corydoras urucu were
collected under collecting permits IBAMA 10102-1. M. Britto
received financial support from CNPq (grants 300189/03-6,
502975/2005-9, and 474788/2006-7) and FAPERJ (grant E-
26/170.687/2007). The authors are participants in the All
Catfish Species Inventory (NSF 0315963).
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