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A new long-snouted species of Corydoras Lacépède, 1803 (Siluriformes: Callichthyidae) from the rio Madeira basin

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A new species of Corydoras is described from the rio Aripuanã, rio Madeira basin, Mato Grosso State, Brazil. The new species can be distinguished from its congeners by the presence of the following features: long mesethmoid, with anterior tip well developed, conspicuously larger than 50% of bone length; posterior margin of dorsal-fin spine with serrations directed towards tip of spine; one to two longitudinal black stripes on flanks; absence of a black blotch across the eyes (mask); absence of a large black blotch on dorsal fin; and transversal black bars on caudal fin. Comments on endemism in interfluvial region between Madeira and Tapajós rivers are briefly discussed.
Corydoras zawadzkii immediately after capture, showing the iridescent greenish yellow coloration of the body. Four branchiostegal rays decreasing in size posteriorly. Hypobranchial 2 somewhat triangular, tip ossified and directed towards anterior portion, posterior margin cartilaginous; ossified portion moderately developed, about same size of cartilaginous portion. Five ceratobranchials with expansions increasing posteriorly; ceratobranchial 1 lacking small process on anterior margin of mesial portion; ceratobranchial 3 notched on posterolateral margin; ceratobranchial 5 toothed on posterodorsal surface, 22–25 (1) teeth aligned in one row. Four epibranchials with similar size; epibranchial 2 slightly larger than others, with small pointed process on laminar expansion of posterior margin; epibranchial 3 with triangular uncinate process on laminar expansion of posterior margin. Two wide pharyngobranchials (3 and 4); pharyngobranchial 3 with triangular laminar expansion on posterior margin. Upper tooth plate oval; 44–47 (1) teeth aligned in three rows on posteroventral surface. Lateral-line canal entering neurocranium through compound pterotic, branching twice before entering sphenotic: pterotic branch with single pore; preoperculomandibular branch conspicuously reduced, with single pore opening close to postotic main canal. Sensory canal continuing through compound pterotic, entering sphenotic as temporal canal, which splits into two branches: one branch giving rise to infraorbital canal, with single pore; other branch entering frontal through supraorbital canal, with two pores. Supraorbital canal branched, running through nasal bone. Epiphyseal branch of supraorbital canal long, pore opening close to frontal fontanel. Nasal canal with two openings, first on posterior edge and second on anterior edge. Infraorbital canal running through entire second infraorbital, extending to infraorbital 1 and opening into two 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. Dorsal fin triangular, located just posterior to third dorsolateral body plate. Dorsal-fin rays II,8 (19), posterior margin of dorsal fin with up to five poorly-developed serrations directed towards tip of spine; serrations disposed on distal half of posterior margin (Fig. 2b). Nuchal plate well developed; almost entirely exposed, with minute odontodes on exposed area; anterior tip covered by thick layer of skin; spinelet short; spine relatively long, adpressed distal tip slightly surpassing origin of last dorsal-fin branched ray; anterior margin with small odontodes. Pectoral fin triangular, its origin just posterior to gill opening. Pectoral-fin rays I,10 (19); posterior margin of pectoral spine with 13–18 well-developed conical serrations along its entire length; serrations directed towards pectoral-fin origin (Fig. 2c). Pelvic fin oblong, located just below second ventrolateral body plate, and at vertical through first branched dorsal-fin ray. Pelvic-fin rays i,5 (19). Adipose fin roughly triangular, separated from base of last dorsal-fin ray by generally six (19) dorsolateral body plates. Anal fin somewhat triangular, located just posterior to 13 th ventrolateral body plates, and at vertical through anterior margin of adipose-fin spine. Anal-fin rays, ii,6 (19). Caudal-fin rays i,11,i (1), i,12,i* (18), four to five dorsal and ventral procurrent rays; bilobed; dorsal lobe slightly larger than ventral lobe. Four to six laterosensory canals on trunk; first ossicle tubular, second ossicle laminar, third, fourth, fifth and sixth, when present, lateral-line canals encased in third, fourth, fifth and sixth dorsolateral body plates, respectively. Body plates with minute odontodes scattered over exposed area, conspicuous line of odontodes
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Accepted by J. Armbruster: 22 Jun. 2016; published: 28 Jul. 2016
ZOOTAXA
ISSN 1175-5326 (print edition)
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Copyright © 2016 Magnolia Press
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Article
http://doi.org/10.11646/zootaxa.4144.3.9
http://zoobank.org/urn:lsid:zoobank.org:pub:4F276108-CD30-4E65-814B-D91D2D17C011
A new long-snouted species of Corydoras Lacépède, 1803
(Siluriformes: Callichthyidae) from the rio Madeira basin
LUIZ FERNANDO CASERTA TENCATT
1
&
WILLIAN MASSAHARU OHARA
2
1
Universidade Estadual de Maringá. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais, Av. Colombo,
5790, Zona 7, 87020–900 Maringá, Paraná, Brazil. E-mail: luiztencatt@hotmail.com
2
Museu de Zoologia da Universidade de São Paulo, Av. Nazaré, 481, Ipiranga, Caixa Postal 42494, 04299–970, São Paulo, SP, Bra-
zil. E-mail: willianmohara@gmail.com
Abstract
A new species of Corydoras is described from the rio Aripuanã, rio Madeira basin, Mato Grosso State, Brazil. The new
species can be distinguished from its congeners by the presence of the following features: long mesethmoid, with anterior
tip well developed, conspicuously larger than 50% of bone length; posterior margin of dorsal-fin spine with serrations di-
rected towards tip of spine; one to two longitudinal black stripes on flanks; absence of a black blotch across the eyes
(mask); absence of a large black blotch on dorsal fin; and transversal black bars on caudal fin. Comments on endemism
in interfluvial region between Madeira and Tapajós rivers are briefly discussed.
Key words: Neotropical region, Amazon, fish, Corydoradinae, taxonomy
Resumo
Uma espécie nova de Corydoras é descrita do rio Aripuanã, bacia do rio Madeira, estado do Mato Grosso, Brasil. A es-
pécie nova pode ser distinguida de suas congêneres pela presença das seguintes características: mesetmóide longo, com a
extremidade anterior bem desenvolvida, conspicuamente maior do que 50% do comprimento do osso; margem posterior
do espinho da nadadeira dorsal com serrilhas voltadas em direção à ponta do espinho; uma a duas faixas pretas longitudi-
nais nos flancos; ausência de uma mancha preta através dos olhos (“máscara”); ausência de uma mancha preta grande na
nadadeira dorsal; e barras transversais pretas na nadadeira caudal. Comentários sobre endemismos na região interfluvial
entre os rios Madeira e Tapajós são brevemente discutidos.
Palavras chave: região Neotropical, Amazônia, peixe, Corydoradinae, taxonomia
Introduction
The Callichthyidae are small- to medium-sized armored catfishes, which can be clearly recognized by the presence
of two longitudinal series of dermal plates on the flanks (Reis, 2003). Corydoras Lacépède, 1803, the largest genus,
comprises about 170 valid species (Britto et al., 2009; Tencatt et al., 2013; Tencatt & Pavanelli, 2015; Tencatt &
Ohara, 2016), and is the most speciose genus of the Siluriformes. The genus is widely distributed in cis-andean
South America, predominantly occurring in the Amazon basin, where more than the half of the known species can
be found (Tencatt & Ohara, 2016). Despite the efforts to elucidate their taxonomy (e.g. Gosline, 1940; Nijssen,
1970; Nijssen & Isbrücker, 1980) and systematics (e.g. Britto, 2003; Alexandrou et al., 2011), several species and
their interrelationships remain poorly known.
The rio Madeira is a tributary to the rio Amazonas, and it harbors 42 species of Corydoras, nearly one quarter
of the species of the genus (Tencatt & Evers, 2016; Tencatt & Ohara, 2016). Recently, Tencatt & Ohara (2016)
described two new species from the rio Madeira basin with similar color patterns, C. brittoi and C. pavanelliae, and
demonstrated that they are from clearly different lineages of species sensu Alexandrou et al. (2011). A third new
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CORYDORAS ZAW ADZKII, NEW SPECI ES
sympatric species also with similar color pattern and different lineage was known at that time, but there were not
enough specimens to describe it. Recently, additional specimens were found mixed with other lots of Corydoras at
the UFRO fish collection. Therefore, it is now possible to provide the formal description of this new species.
Material and methods
Measurements were obtained using digital caliper to the nearest millimeter. Morphometric and meristic data were
taken following Reis (1997) with the modifications of Tencatt et al. (2013). Morphometrics are reported as
proportion of standard length (SL) or as proportions of head length (HL). Homology of barbels follows Britto &
Lima (2003). For the osteological analysis, some specimens were cleared and stained (CS) according to the
protocol of Taylor & Van Dyke (1985). Osteological terminology was based on Reis (1998), with the exception of
parieto-supraoccipital instead of supraoccipital (Arratia & Gayet, 1995), compound pterotic instead of pterotic-
supracleithrum (Aquino & Schaefer, 2002), and scapulocoracoid instead of coracoid (Lundberg, 1970).
Nomenclature of the latero-sensory canals and preopercular pores are according to Schaefer & Aquino (2000) and
Schaefer (1988), respectively. The supra-preopercle sensu Huysentruyt & Adriaens (2005) was treated here as a
part of the hyomandibula according to Vera-Alcaraz (2013). Vertebral counts include only free centra, with the
compound caudal centrum (preural 1+ ural 1) counted as a single element. Pharyngeal teeth were counted in both
sides of the hyoid and branchial arches. The stripes were counted following Tencatt & Ohara (2016). In the
description, numbers in parentheses represent the total number of specimens with those counts. Numbers with an
asterisk refer to the counts of the holotype.
Comparative data of Corydoras amapaensis Nijssen, 1972, C. coriatae Burgess, 1997, C. cortesi Castro, 1987,
C. filamentosus Nijssen & Isbrücker, 1983, C. semiaquilus Weitzman, 1964, C. serratus Sands, 1995, C. solox
Nijssen & Isbrücker, 1983 and C. vittatus Nijssen, 1971 were obtained through their original descriptions and/or
high resolution photographs of type specimens hosted in the Natural History Museum, London. Photographs of
other pertinent type specimens were available for examination through the All Catfish Inventory website (Morris et
al., 2006). Institutional abbreviations are: AI, Asociatión Ictiológica de La Plata, La Plata; ANSP, Academy of
Natural Sciences of Drexel University, Philadelphia; BMNH, Natural History Museum, London; INPA, Instituto
Nacional de Pesquisas da Amazônia, Manaus; LBP, Laboratório de Biologia de Peixes da Universidade Estadual
Paulista “Júlio de Mesquita Filho”, Botucatu; MCP, Museu de Ciências e Tecnologia da Pontifícia Universidade
Católica, Porto Alegre; MCZ, Museum of Comparative Zoology, Harvard University, Cambridge; MNRJ, Museu
Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro; MUSM, Museo de Historia Natural de la
Universidad Nacional Mayor de San Marcos, Lima. MZUSP, Museu de Zoologia da Universidade de São Paulo,
São Paulo; NMW, Naturhistorisches Museum, Wien; NRM, Naturhistoriska Riksmuseet, Stockholm; NUP,
Coleção Ictiológica do Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura da Universidade Estadual de
Maringá, Maringá; ROM, Royal Ontario Museum, Toronto; ZUFMS-PIS, Coleção Zoológica de Referência da
Universidade Federal de Mato Grosso do Sul, Campo Grande.
Corydoras zawadzkii, new species
(Figs. 1, 2, 3, Table 1)
Holotype. MNRJ 45565, 48.7 mm SL, Brazil, Mato Grosso State, Colniza Municipality, Guariba District, igarapé
Pica-Pau, a tributary to the rio Juma, rio Aripuanã drainage, rio Madeira basin, 09°22’27”S 60°02’59”W; W. M.
Ohara, D. B. Hungria & B. Barros, 16 Jul 2013.
Paratypes. All from Brazil, Mato Grosso State, Colniza Municipality, Guariba District, rio Aripuanã drainage,
rio Madeira basin. MZUSP 118817, 5, 35.1–50.0 mm SL, tributary of igarapé Água Branca, itself a tributary of rio
Guariba, 09°06’47”S 60°25’14”W; W. M. Ohara, D. B. Hungria & B. Barros, 15 Jul 2013. INPA 52737, 4, 37.3–
44.3 mm SL; MCP 49452, 3, 41.1–46.8 mm SL; NUP 17823, 4, 43.8–46.8 mm SL; NUP 17824, 1 CS, 39.9 mm
SL; ZUFMS-PIS 4181, 1, 46.7 mm SL; same data as the holotype.
Diagnosis. Corydoras zawadzkii can be distinguished from its congeners, with exception of the species from
lineages 1 and 8 sensu Alexandrou et al. (2011), by the presence of a long mesethmoid, with anterior tip well
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developed, conspicuously larger than 50% of the bone length (vs. short, with anterior tip smaller than 50% of the
bone length). The new species can be distinguished from the species of lineage 8 by the presence of the posterior
margin of dorsal spine with serrations directed towards tip of the spine (vs. directed towards origin of spine); from
the species of lineage 1, except C. acutus Cope, 1872, C. amapaensis, C. coriatae, C. cortesi, C. filamentosus, C.
fowleri Böhlke, 1950, C. geoffroy Lacépède, 1803, C. narcissus Nijssen & Isbrücker, 1980, C. semiaquilus, C.
serratus, C. solox, C. treitlii Steindachner, 1906, and C. vittatus, by the presence of one to two longitudinal black
stripes on flanks (vs. four to five longitudinal rows of black spots on flanks, which may be coalescent and form
stripes in some specimens of C. maculifer Nijssen & Isbrücker, 1971; absence of stripes on flanks in remaining
species). Corydoras zawadzkii can be distinguished from C. amapaensis, C. coriatae, C. cortesi, C. fowleri, C.
narcissus, C. semiaquilus, C. serratus, and C. solox by the absence of a black blotch across the eyes (or mask; vs.
mask present); from C. acutus by the absence of a large black blotch on dorsal fin (vs. presence); from C. treitlii by
the presence of transversal black bars on caudal fin (vs. absence).
Description. Morphometric data presented in Table 1. Head compressed with acutely convex dorsal profile;
roughly triangular in dorsal view. Snout conical and long; conspicuously pointed. Head profile slightly concave
from tip of snout to anterior nares; ascending and slightly convex from this point to dorsal-fin origin; region
between eye and posterior tip of parieto-supraoccipital slightly concave in some specimens. Profile slightly convex
along dorsal-fin base. Postdorsal-fin body profile slightly concave to adipose-fin spine; concave from this point to
caudal-fin base. Ventral profile of body nearly straight from isthmus to pectoral-fin origin; slightly convex from
this point to pelvic-fin origin; slightly convex from this point to anal-fin origin; abruptly concave until caudal-fin
base. Body roughly elliptical in cross section at pectoral girdle, gradually becoming more compressed toward
caudal fin. Greatest body depth slightly anterior to vertical through dorsal-fin origin.
TABLE 1. Morphometric data for holotype and paratypes of Corydoras zawadzkii. Values for holotype (included in
range, n = 19), range and median ± SD = (standard deviation).
Holotype Range Mean±SD
Standard length (mm) 48.7 35.1–50.0 42.6±4.4
Percents of standard length
Depth of body 37.0 33.6–37.9 35.9±1.1
Predorsal distance 49.9 43.7–51.8 49.6±1.7
Prepelvic distance 47.6 46.2–49.1 47.7 ±0.9
Preanal distance 80.1 79.2–82.4 80.4±0.9
Preadipose distance 84.4 82.1–85.3 83.7±0.9
Length of dorsal-fin spine 22.6 21.3–24.7 22.9±1.0
Length of pectoral-fin spine 20.3 20.1–23.0 21.2±0.8
Length of adipose-fin spine 8.4 8.4–11.4 10.0±0.8
Depth of caudal peduncle 14.0 13.7–16.0 14.7±0.6
Length of dorsal-fin base 19.1 17.4–19.5 18.5±0.6
Dorsal to adipose distance 17.7 17.1–20.2 18.5±0.9
Maximum cleithral width 25.3 22.8–25.3 24.1±0.7
Head length 42.5 41.4–45.2 43.5±0.9
Length of maxillary barbel 18.9 13.4–22.1 18.4±1.7
Percents of head length
Head depth 81.2 74.4–81.2 77.6±2.1
Least interorbital distance 23.7 21.2–24.8 23.1±0.9
Horizontal orbit diameter 18.8 18.8–23.8 20.6±1.3
Snout length 47.3 42.9–47.9 45.9±1.5
Least internarial distance 11.6 9.5–13.0 11.2±1.1
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FIGURE 1. Dorsal (top), lateral (middle) and ventral (bottom) views of Corydoras zawadzkii, holotype, MNRJ 45565, 48.7
mm SL. Photo by Celso Ikedo.
Eye rounded, located dorsolaterally on head; orbit delimited dorsally by lateral ethmoid, frontal and sphenotic,
ventrally by infraorbitals. Anterior and posterior nares close to each other, only separated by flap of skin. Anterior
naris tubular. Posterior naris close to anterodorsal margin of orbit, separated from it by distance equal to naris
diameter. Mouth small, subterminal, width smaller than bony orbit diameter. Maxillary barbel long, almost
reaching to anteroventral limit of gill opening. Outer mental barbel slightly longer than maxillary barbel. Inner
mental barbel fleshy, with base close to its counterpart. Area at the corner of the mouth, ventral to the maxillary
barbel, with a reduced fleshy flap. Small rounded papillae covering entire surface of all barbels, upper and lower
lips, and isthmus.
Mesethmoid long; anterior tip well developed, conspicuously larger than 50% of bone length (see Britto, 2003:
123, character 1, state 0; Fig. 1A); posterior portion relatively narrow, covered by thick layer of skin. Nasal slender,
curved laterally, inner margin with moderately-developed laminar expansion; outer margin with reduced laminar
expansion; mesial border contacting only frontal. Frontal elongated, relatively narrow, with width smaller than half
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of entire length; anterior projection short, size smaller than nasal length. Frontal fontanel large, conspicuously
slender; posterior tip markedly entering anterior margin of parieto-supraoccipital. Parieto-supraoccipital wide,
posterior process long, contacting nuchal plate.
Two laminar infraorbitals with minute odontodes; infraorbital 1 large, ventral laminar expansion moderately
developed; anterior portion with poorly-developed expansion (Fig. 2a); infraorbital 2 small, thickened; with
posterior laminar expansion well developed; posteroventral margin contacting posterodorsal ridge of
hyomandibula, dorsal tip contacting sphenotic and compound pterotic (Fig. 2a). Posterodorsal ridge of
hyomandibula close to its articulation with opercle oblong; exposed, conspicuously slender; dorsal ridge of
hyomandibula between compound pterotic and opercle covered by thick layer of skin; exposed areas bearing small
odontodes. Interopercle covered by thin layer of skin, somewhat triangular, anterior projection well developed.
Preopercle slender, elongated, minute odontodes on external surface. Opercle dorsoventrally elongated, width
smaller than half of entire length; free margin convex; posterodorsal region with slightly concave area in some
specimens; without serrations and covered by small odontodes. Anteroventral portion of cleithrum partially
exposed; posterolateral portion of scapulocoracoid exposed; minute odontodes placed sparsely on exposed areas.
Vertebral count 23 (1); ribs 5 (1), first pair conspicuously large; complex vertebra slender. Neural and haemal
spines with serrated laminar expansions on anterior margin of proximal region.
FIGURE 2. Corydoras zawadzkii, NUP 17824, paratype, 39.9 mm SL, showing (a) the poorly-developed ventral expansion of
the infraorbital 1 (io1) and infraorbital 2 (io2) in contact with compound pterotic (cpt) (detail), (b) dorsal-fin spine with
serrations directed towards the tip of the spine and disposed distally, and (c) pectoral-fin spine with conical well-developed
serrations directed towards origin of spine. In detail, the dotted line represents the suture between sphenotic (sph) and
compound pterotic bones. Scale bar = 1.0 mm.
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FIGURE 3. Corydoras zawadzkii immediately after capture, showing the iridescent greenish yellow coloration of the body.
Four branchiostegal rays decreasing in size posteriorly. Hypobranchial 2 somewhat triangular, tip ossified and
directed towards anterior portion, posterior margin cartilaginous; ossified portion moderately developed, about
same size of cartilaginous portion. Five ceratobranchials with expansions increasing posteriorly; ceratobranchial 1
lacking small process on anterior margin of mesial portion; ceratobranchial 3 notched on posterolateral margin;
ceratobranchial 5 toothed on posterodorsal surface, 22–25 (1) teeth aligned in one row. Four epibranchials with
similar size; epibranchial 2 slightly larger than others, with small pointed process on laminar expansion of posterior
margin; epibranchial 3 with triangular uncinate process on laminar expansion of posterior margin. Two wide
pharyngobranchials (3 and 4); pharyngobranchial 3 with triangular laminar expansion on posterior margin. Upper
tooth plate oval; 44–47 (1) teeth aligned in three rows on posteroventral surface.
Lateral-line canal entering neurocranium through compound pterotic, branching twice before entering
sphenotic: pterotic branch with single pore; preoperculomandibular branch conspicuously reduced, with single
pore opening close to postotic main canal. Sensory canal continuing through compound pterotic, entering sphenotic
as temporal canal, which splits into two branches: one branch giving rise to infraorbital canal, with single pore;
other branch entering frontal through supraorbital canal, with two pores. Supraorbital canal branched, running
through nasal bone. Epiphyseal branch of supraorbital canal long, pore opening close to frontal fontanel. Nasal
canal with two openings, first on posterior edge and second on anterior edge. Infraorbital canal running through
entire second infraorbital, extending to infraorbital 1 and opening into two 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.
Dorsal fin triangular, located just posterior to third dorsolateral body plate. Dorsal-fin rays II,8 (19), posterior
margin of dorsal fin with up to five poorly-developed serrations directed towards tip of spine; serrations disposed
on distal half of posterior margin (Fig. 2b). Nuchal plate well developed; almost entirely exposed, with minute
odontodes on exposed area; anterior tip covered by thick layer of skin; spinelet short; spine relatively long,
adpressed distal tip slightly surpassing origin of last dorsal-fin branched ray; anterior margin with small odontodes.
Pectoral fin triangular, its origin just posterior to gill opening. Pectoral-fin rays I,10 (19); posterior margin of
pectoral spine with 13–18 well-developed conical serrations along its entire length; serrations directed towards
pectoral-fin origin (Fig. 2c). Pelvic fin oblong, located just below second ventrolateral body plate, and at vertical
through first branched dorsal-fin ray. Pelvic-fin rays i,5 (19). Adipose fin roughly triangular, separated from base of
last dorsal-fin ray by generally six (19) dorsolateral body plates. Anal fin somewhat triangular, located just
posterior to 13
th
ventrolateral body plates, and at vertical through anterior margin of adipose-fin spine. Anal-fin
rays, ii,6 (19). Caudal-fin rays i,11,i (1), i,12,i* (18), four to five dorsal and ventral procurrent rays; bilobed; dorsal
lobe slightly larger than ventral lobe.
Four to six laterosensory canals on trunk; first ossicle tubular, second ossicle laminar, third, fourth, fifth and
sixth, when present, lateral-line canals encased in third, fourth, fifth and sixth dorsolateral body plates,
respectively. Body plates with minute odontodes scattered over exposed area, conspicuous line of odontodes
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confined on posterior margins; dorsolateral body plates 24 (2), 25* (14), 26 (3); ventrolateral body plates 21 (1),
22* (15), 23 (3); dorsolateral body plates along dorsal-fin base 7; dorsolateral body plates between adipose- and
caudal-fin 8* (12), 9 (7); preadipose platelets 2 (2), 3* (15), 4 (2); small platelets covering base of caudal-fin rays;
small platelets disposed dorsally and ventrally between junctions of lateral plates on posterior portion of caudal
peduncle. Anterodorsal margin of orbit, above the junction of frontal and lateral ethmoid, ventral margin of nasal
capsule, and snout with small platelets (Fig. 2a). Ventral surface of head and trunk covered by small irregular
platelets.
Color in alcohol. Overall color of body in Figure 1. Ground color of body light yellow, with top of head dark
brown; region of nasal bone, ventral portion of nasal capsule, and ventral portion of infraorbital 1 dark brown or
black. Snout densely covered by black chromatophores on dorsal and lateral portions; presence of diffuse slender
oblique black stripe directed towards snout tip on dorsolateral portion of snout in some specimens. Maxillary
barbel and proximal region of outer mental barbel covered by black chromatophores. Anterior portion of body with
irregular black blotches. Dorsal portion of body with black chromatophores, more concentrated around nuchal
plate and dorsal-fin base, becoming sparse towards caudal peduncle. Body with one to two longitudinal black
stripes. Dorsal half of dorsolateral body plates with irregular black blotches anteriorly to adipose fin; blotches not
well aligned. Ventral portion of dorsolateral body plates just above midline of flank blackened, forming thicker
conspicuous longitudinal stripe along flank; intensely black spots well aligned on ventral portion of stripe. Ventral
portion of dorsal half of ventrolateral body plates blackened with well-aligned series of irregular black blotches,
generally forming slender longitudinal black stripe along flank; blotches not coalescent in some specimens; stripe
absent or diffuse posteriorly to anal-fin last branched ray region. Posterior margin of lateral body plates blackened,
becoming diffuse towards their distal portions. Dorsal fin with sparse brown blotches; dorsal half of region
between dorsal spine and first branched ray, including membrane, with more concentrated black chromatophores;
dorsal-fin spine blackish. Pectoral fin brownish yellow. Pelvic fin hyaline. Adipose fin with posterodorsal margin
with black chromatophores; dorsal portion of adipose-fin spine black. Caudal fin covered by black spots; spots
arranged in five to 10 transversal black bars.
Color in life. Similar to preserved specimens, but with dorsal region of body yellowish olive; ventral region
whitish yellow. Longitudinal black stripes conspicuous. Body covered by greenish yellow iridescent coloration
(Fig. 3).
Sexual dimorphism. Males have a lanceolate genital papilla (vs. narrow), which is common to all
Corydoradinae (see Nijssen & Isbrücker, 1980; Britto, 2003), but no other dimorphism was observed.
Geographical distribution. Corydoras zawadzkii is known from two localities, both tributaries of the rio
Guariba, middle rio Aripuanã, rio Madeira basin, Mato Grosso State, Brazil (Fig. 4).
Ecological notes. The type locality of Corydoras zawadzkii is located at 130 meters above sea level, and it is a
small clear water stream, 2–3 m wide and 0.5–1.8 m deep, with preserved riparian vegetation, swift water current,
and bottom composed mainly by sand and dead leaves. Specimens of C. zawadzkii were observed at night during
capture in shallow portions of the stream in small groups (three individuals), and sometimes associated with
Corydoras pavanelliae and Corydoras brittoi. Other species collected syntopically were Aphyocharax sp.,
Bryconops cf. giacopinii (Fernández-Yépez), Gymnorhamphichthys rondoni (Miranda Ribeiro), Hemigrammus
bellottii (Steindachner), Hemigrammus melanochrous Fowler, Hoplias malabaricus (Bloch), Hypostomus
pyrineusi (Miranda Ribeiro), Moenkhausia collettii (Steindachner), Moenkhausia oligolepis (Günther),
Parotocinclus cf. aripuanensis Garavello, Phenacogaster cf. beni Eigenmann, Poptella compressa (Günther),
Potamorrhaphis guianensis (Jardine), and Xenurobrycon polyancistrus Weitzman.
Etymology. Corydoras zawadzkii is named in honor of Dr. Cláudio Henrique Zawadzki, professor at the
Universidade Estadual de Maringá (UEM), for his comprehensive contributions to the knowledge of Neotropical
ichthyofauna, especially of the Loricariidae. Cláudio is a dear friend that directly participates in the professional
formation of the first author. Treated as a genitive.
Conservation status. Corydoras zawadzkii is so far known only from two tributaries to the rio Aripuanã and
its conservation status is uncertain based on the currently available data of its geographic distribution. Despite that,
no imminent threats to the species were detected in the area, and considering that it occurs in a protected area
(Reserva Extrativista Guariba Roosevelt), Corydoras zawadzkii would be classified as Least Concern (LC)
according to the International Union for Conservation of Nature (IUCN) categories and criteria (IUCN Standards
and Petitions Subcommittee, 2014).
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FIGURE 4. Map showing the known geographical distribution of Corydoras zawadzkii. The red square represents its type-
locality, the igarapé Pica-Pau, a tributary to the rio Juma, and the black square represents the igarapé Água Branca, itself a
tributary of rio Guariba, rio Aripuanã drainage, rio Madeira basin.
Discussion
The presence of convergent color patterns in Corydoras has been supported by a series of studies (e.g. Britto et al.,
2009; Alexandrou et al., 2011; Tencatt et al., 2013; Tencatt & Pavanelli, 2015; Tencatt & Britto, 2016; Tencatt &
Ohara, 2016). Initially, the simplest way to recognize the species with homoplastic color pattern is through the
morphological pattern of their snout, which is specific to each lineage of species, as demonstrated by Alexandrou et
al. (2011). Corydoras zawadzkii has the typical long-snouted pattern of species from lineage 1 of Alexandrou et al.
(2011). In addition to the peculiar long snout, C. zawadzkii can be unequivocally considered as a member of
lineage 1 by the presence of an upper pharyngeal tooth plate with three series of teeth (vs. two), which is an
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exclusive feature of this lineage. Species of lineage 8, such as C. brittoi, also have a long mesethmoid, and the
species of lineage 1 can be promptly distinguished from those of lineage 8 by the presence of conical serrations on
posterior margin of pectoral spine (vs. laminar), and the posterior margin of the dorsal-fin spine with serrations
directed towards the tip of the spine (vs. directed towards the origin of the spine).
Among the species of lineage 1, Corydoras zawadzkii has a unique color pattern. Generally, specimens of C.
zawadzkii have two longitudinal black stripes along the midline of the flank, being thus promptly diagnosed from
all other lineage 1 species. Uncommonly, the new species can have only one black stripe along flanks, as in other
lineage 1 congeners, however, even in this case, its pattern is clearly different from them. In C. acutus, C. coriatae,
C. cortesi, C. filamentosus, C. fowleri, C. semiaquilus, C. treitlii and C. vittatus the stripe partially or entirely
covers the midline of the flank (vs. not touching midline of flank). It differs from C. amapaensis, C. geoffroy, C.
narcissus C. serratus and C. solox by having the black stripe slender (vs. wider, at least two times thicker).
Corydoras zawadzkii, as well as C. pavanelliae and C. brittoi, is known only from the middle rio Aripuanã.
According to Benine (2002) the rio Aripuanã is apparently an area of endemism for fishes. Many endemic species
have been recorded from the rio Aripuanã drainage, with some species known only upstream of the Dardanelos and
Andorinha waterfalls (e.g. Geophagus mirabilis Deprá, Kullander, Pavanelli & Graça, Leporinus gomesi Garavello
& Santos, Trachycorystes menezesi Britski & Akama), downstream them (e.g. Hypostomus dardanelos Zawadzki
& Hollanda-Carvalho, Jupiaba citrina Zanata & Ohara, Parotocinclus aripuanensis Garavello), or in both of them
(e.g. Crenicihla hemera Kullander, Moenkhausia levidorsa Benine, Utiaritichthys longidorsalis Jégu, Tito de
Morais & Santos) (Kullander, 1995; Benine, 2002; Zanata & Ohara, 2009; Deprá et al., 2014; Zawadzki &
Hollanda-Carvalho, 2015).
The interfluvial region between the Madeira and Tapajós rivers, is considered an important area of endemism
in the Amazon basin for birds (e.g. Haffer, 1978; Bates et al., 1998; Cracraft, 1985), primates (Silva & Oren, 1996),
terrestrial vertebrates (Ron, 2000; Silva et al., 2005), butterflies (Hall & Harvey, 2002) and vascular plants (Prance,
1982). Some apparently endemic species of fish occur in other tributaries (not the rio Aripuanã) of the right margin
from the rio Madeira basin (e.g. Acestridium scutatum Reis & Lehmann, Acestrorhynchus isalineae Menezes &
Géry, Archolaemus santosi Vari, de Santana & Wosiacki), while others are known only from tributaries of the left
margin from rio Tajapós basin (e.g. Hasemania nambiquara Bertaco & Malabarba, Hyphessobrycon peugeoti
Ingenito, Lima & Buckup, Leporinus reticulatus Britski & Garavello). However, other species of fish are
distributed in both systems (e.g. Inpaichthys kerri Géry & Junk, Hemigrammus silimoni Britski & Lima,
Moenkhausia levidorsa). Thus, for the fish, the interfluvial region between the Madeira and Tapajós rivers agrees
with the patterns already found in other groups of organisms, as mentioned above. Additionally, other patterns of
endemism can also occur, as discussed by Ohara & Lima (2015).
The fish fauna from the middle and lower areas between the Madeira and Tapajós rivers is poorly known,
further extensive studies on the distribution will be necessary to corroborate or contradict the delimitation of this
area of endemism for fish. Then we may see that the interfluvial area of fish endemicity contradicts the idea that
river basins correspond to major areas of endemism, which was previously assigned for the rio Araguaia (Lima &
Moreira, 2003), rio Tocantins (Bertaco & Lucinda 2005; Bertaco & Lucinda, 2006; Ribeiro et al., 2008; Lucinda et
al., 2010), upper rio Tapajós (Carvalho & Bertaco, 2006; Britski & Lima, 2008; Vari & Calegari, 2014), and upper
rio Xingu (Birindelli et al., 2009). Future studies should evaluate if other interfluvial areas, mainly of Guiana and
Brazilian shields, can represent endemic areas for fishes.
Comparative material examined. All the following specimens were examined: Corydoras acutus: MNRJ
3985, 2, 47.1–54.8 mm SL; Peru: unknown Departament; Sansho-Caño. Corydoras adolfoi: MZUSP 26641, 1,
holotype, 32.5 mm SL; Brazil: Amazonas: tributary to the upper rio Negro. Corydoras ambiacus: MCP 26178, 1,
42.5 mm SL; Peru: Loreto: rio Pacaya. MCP 26209, 10 of 19, 25.0–33.3 mm SL; Caño Yarina: rio Ucayali.
MZUSP 26053, 2, 41.8–47.2 mm SL; Iamiriacocha. Corydoras approuaguensis: MZUSP 27895–6, 2, paratypes,
43.0–46.1 mm SL; French Guyana: Cayenne: rio Approuague. Corydoras araguaiaensis: MZUSP 87155, 4 of 33,
24.9–46.7 mm SL, 2 CS, 27.6–31.8 mm SL; Brazil: Mato Grosso: Corixo da Saudade. Corydoras areio: ZUFMS-
PIS 1314, 15, 34.4–41.9 mm SL, 2 CS, 38.1–38.5 mm SL; Brazil: Mato Grosso do Sul: Periquito stream.
Corydoras armatus: MZUSP 49567, 1, 45.3 mm SL; Brazil: Amazonas: rio Acre. Corydoras aurofrenatus: NRM
23529, 10 of 33, 31.4–45.7 mm SL; Paraguay: Concepción: Arroyo Laguna Penayo. Corydoras bifasciatus:
MZUSP 38976, 16, paratypes, 23.6–30.0 mm SL; Brazil: Pará: rio Cururu. Corydoras blochi: MZUSP 8580, 3,
paratypes, 31.0–42.6 mm SL; Brazil: Roraima: rio Uraricoera. Corydoras bondi: ROM 66202, 7 of 134, 33.8–39.9
mm SL, 3 CS of 134, 36.7–38.6 mm SL; Guyana: Barima-Waini: Waikerebi Creek. Corydoras brevirostris: LBP
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3080, 10, 23.8–27.7 mm SL, 3 CS, 25.8–27.9 mm SL; Venezuela: Bolívar: río Orinoco. Corydoras britskii:
ZUFMS-PIS 862, 12, 72.0–78.0 mm SL; Brazil: Mato Grosso do Sul: rio Vermelho. Corydoras brittoi: MNRJ
43316, holotype, 38.1 mm SL; Brazil: Mato Grosso: rio Guariba. Corydoras carlae: NUP 711, 1, 47.9 mm SL;
Brazil: Paraná: rio Tormenta. NUP 4425, 1 CS, 45.0 mm SL; rio Tormenta. Corydoras cochui: MZUSP 89055, 6,
18.7–23.6 mm SL; Brazil: Goiás: Tocantins: rio do Peixe II. MZUSP 35838, 4 of 6, 16.1–18.5 mm SL; Brazil:
Goiás: Tocantins: rio Javaés. Corydoras condiscipulus: MZUSP 38957, 7, paratypes, 34.1–40.3 mm SL; French
Guyana: Cayenne: Cumuri Creek. Corydoras coppenamensis: MZUSP 13995–99, 5, paratypes, 28.2–34.9 mm SL;
Suriname: Saramacca: rio Coppename. Corydoras crimmeni: MZUSP 52490, 1, holotype, 36.1 mm SL; Brazil:
Roraima: aquarium specimens said to be from near the town of Boa Vista, possibly from the rio Branco. Corydoras
davidsandsi: MZUSP 110066, 4 of 40, 36.0–41.9 mm SL, 2 CS of 40, 40.9–42.1 mm SL; Brazil: Amazonas: rio
Inambú. Corydoras difluviatilis: MZUSP 75268, 1, holotype, 39.8 mm SL; Brazil: São Paulo: Paulicéia stream.
Corydoras diphyes: ANSP 169756, 2, 40.7–43.1 mm SL; Paraguay: Alto Paraná: drainage ditches north of km 250
(2 km east of Juan E. O’Leary on route 7). Corydoras ehrhardti: NUP 11255, 15, 36.5–46.8 mm SL; Brazil:
Paraná: rio São Pedro. Corydoras elegans: MZUSP 26017, 6, 25.9–28.3 mm SL; Peru: Ucayali: Lobococha.
Corydoras ephippifer: MZUSP 31605, 2, 44.9–49.1 mm SL; Brazil: Amapá: rio Cupixi.
Corydoras eques: MCZ 8204, 4 of 12, paratypes, 37.6–44.4 mm SL; Brazil: Amazonas: rio Amazonas at
Codajás. Corydoras eversi: MNRJ 43195, holotype, 44.5 mm SL; Brazil: Goiás: tributary to the rio Araguaia.
Corydoras flaveolus: MZUSP 424, holotype, 33.4 mm SL; Brazil: São Paulo: rio Piracicaba. Corydoras fowleri:
LBP 12462, 9, 44.3–59.9 mm SL, 1 CS, 50.4 mm SL; Peru: Loreto: tributary to the rio Ampiyacu. Corydoras
garbei: MNRJ 18089, 14, 19.2–25.3 mm SL, 2 CS, 25.9–27.4 mm SL; Brazil: Minas Gerais: Perta-Pé lagoon.
Corydoras geoffroy: MZUSP 38984, 2, paratypes, 38.7–45.2 mm SL; Suriname: Marowijne: fall in the rio
Oelemari. Corydoras gossei: MZUSP 38977, 6, paratypes, 48.4–53.4 mm SL; Brazil: Rondônia: tributary to the rio
Mamoré. Corydoras griseus: MZUSP 108896, 4 of 13, 31.5–36.2 mm SL, 2 CS of 13, 30.6–34.5 mm SL; Guyana:
Potaro-Siparuni: tributary to the rio Kuribrong. Corydoras guapore: ZUFMS-PIS 4000, 5, 26.9–33.6 mm SL, 2 CS,
28.8–29.2 mm SL; Brazil: Mato Grosso: rio Guaporé. Corydoras gryphus: MNRJ 40770, holotype, 32.3 mm SL;
Brazil: Paraná: rio Paraná (near Ponte da Amizade). NUP 14676, 3 CS, paratypes, 27.7–32.4 mm SL; Brazil:
Paraná: rio Paraná (near Ponte da Amizade). Corydoras hastatus: NUP 6862, 116, 13.1–20.7 mm SL; Brazil: Mato
Grosso: baía Caiçara. Corydoras incolicana: MZUSP 45717, holotype, 47.6 mm SL; Brazil: Amazonas: rio Içana.
Corydoras julii: NUP 16225, 1, 46.8 mm SL; Brazil: Piauí: rio Atalaia. Corydoras kanei: MZUSP 52489, holotype,
36.6 mm SL; Brazil: Roraima: aquarium specimens said to be from near the town of Boa Vista, possibly from the
rio Branco. Corydoras knaacki: MUSM 52730, holotype, 35.6 mm SL; Peru: Madre de Dios: draining into the río
Inambari. Corydoras lacrimostigmata: MNRJ 40725, holotype, 31.8 mm SL; Brazil: Paraná: rio Maria Flora. NUP
14657, 3 CS, paratypes, 30.9–34.5 mm SL: rio Nestor. Corydoras longipinnis: AI 221, holotype, 59.5 mm SL;
Argentina: Santiago del Estero: río Sali. NUP 14440, 2 CS, 29.9–33.4 mm SL: Pampa-Mayo stream. Corydoras
lymnades: MNRJ 15765, 6, 15.8–17.7 mm SL, 2 CS, 18.1–18.4 mm SL; Brazil: Minas Gerais: rio Peruaçu. MNRJ
40186, holotype, 29.7 mm SL; Brazil: Minas Gerais: rio Guarda-Mor. Corydoras maculifer: NUP 8970, 2, 42.0–
46.0 mm SL; Brazil: Tocantins: ribeirão Xambioazinho. Corydoras melanistius: BMNH 1864.1.21.86, 1, lectotype,
35.0 mm SL; Guyana: Unknown region:, rio Essequibo. Corydoras melini: MZUSP 81163, 2, 37.0–45.0 mm SL;
Brazil: Amazonas: rio Tiquié. Corydoras multimaculatus: MCP 29025, 2, 20.1–25.4 mm SL; Brazil: Minas Gerais:
rio Peruaçu. Corydoras napoensis: MZUSP 26341, 1, paratype, 27.8 mm SL; Peru: Loreto: Moronacocha.
Corydoras narcissus: LBP 10094, 1, 64.0 mm SL; Brazil: Amazonas: tributary to the rio Purus. Corydoras
nattereri: MZUSP 110255, 4 of 31, 32.0–32.8 mm SL, 2 CS of 31, 32.3–34.4 mm SL; Brazil: São Paulo: rio
Paraitinga. Corydoras panda: ROM 55815, 6, 26.5–39.7 mm SL; Peru: Huánuco: above Panguana in Llullapichis
drainage. Corydoras pantanalensis: NUP 10188, 1 CS, 46.4 mm SL; Brazil: Mato Grosso: Baía Sinhá Mariana;
NUP 12593, 21, 38.7–51.2 mm SL; Brazil: Mato Grosso do Sul: tributary to the rio Miranda. Corydoras
parallelus: MZUSP 45716, holotype, 47.4 mm SL; Brazil: Amazonas: rio Içana. Corydoras pavanelliae: MNRJ
43317, holotype, 45.1 mm SL; Brazil: Mato Grosso: rio Guariba. Corydoras pinheiroi: MZUSP 48099, holotype,
54.3 mm SL; Brazil: Rondônia: tributary to the rio Ribeiro, at Guajará-Mirim. Corydoras potaroensis: ROM
61526, 3 of 15, 35.0–44.8 mm SL, 2 CS of 15, 32.6–35.1 mm SL; Guyana: Potaro-Siparuni: rio Potaro. Corydoras
pygmaeus: MZUSP 26344, 4, 13.5–20.0 mm SL; Peru: Loreto: Moronacocha. Corydoras reticulatus: MZUSP
28752, 3, 37.3–45.1 mm SL; Peru: Ucayali: Iamiriacocha, Masisea. Corydoras robineae: MZUSP 27175, holotype,
33.7 mm SL; Brazil: Amazonas: rio Aiuana. Corydoras sarareensis: MZUSP 48100, holotype, 40.9 mm SL;
Brazil: Mato Grosso: rio Sararé. Corydoras septentrionalis: MZUSP 27953, 12, 28.7–41.9 mm SL; Venezuela:
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Apure: Caño Caiçara. Corydoras seussi: MZUSP 49323, 10, paratypes, 44.3–54.0 mm SL; Brazil: Rondônia:
tributary to the rio [Pacaás Novos], near Guajará-Mirim. Corydoras similis: LBP 10648, 7, 21.4–34.3 mm SL;
Brazil: Acre: rio Iquiri. Corydoras splendens: NUP 12990, 1, 43.7 mm SL; Brazil: Goiás: tributary to the rio
Araguaia. NUP 10195, 1 CS, 54.6 mm SL; Brazil: Mato Grosso: Pai Caetano lake. Corydoras stenocephalus:
MNRJ 3625, 3, 31.2–62.3 mm SL; Brazil: Amazonas: rio Javari. Corydoras sterbai: MZUSP 94998, 1, 39.9 mm
SL; Brazil: Mato Grosso: rio Guaporé. Corydoras treitlii: NUP 16224, 3, 21.5–45.6 mm SL; Brazil: Maranhão: rio
Medonho. Corydoras trilineatus: MZUSP 30857, 3 of 25, 40.9–44.1 mm SL, 2 CS of 25, 44.2–43.8 mm SL;
Brazil: Acre: rio Tarauacá. Corydoras tukano: MZUSP 82100, holotype, 40.9 mm SL; Brazil: Amazonas: rio
Tiquié. Corydoras xinguensis: MZUSP 38987, 1, paratype, 34.5 mm SL; Brazil: Mato Grosso: igarapé upstream
Porori village. Corydoras zygatus: MZUSP 30858, 4 of 15, 41.7–47.3 mm SL; Brazil: Acre: rio Tarauacá.
Acknowledgments
The Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (Nupélia) of the Universidade Estadual de
Maringá provided logistical support. The authors are grateful to Carlos Lucena (MCP), Oscar Shibatta (MZUEL),
Mário de Pinna, Aléssio Datovo and Osvaldo Oyakawa (MZUSP), Cláudio Oliveira (LBP), Luiz Malabarba
(UFRGS) and Otávio Froehlich (in memoriam) (ZUFMS-PIS) for hosting museum visits and loan of material. We
also thank Sven Kullander (NRM), Juan Mirande (Fundación Miguel Lillo), Jorge Casciotta and Adriana Almirón
(AI), Hernán López-Fernández, Don Stacey and Erling Holm (ROM) for the loan and/or donation of several
specimens analyzed in this paper. We thank Carlos Lucena and Héctor Vera-Alcaraz (MCP), Luiz Malabarba,
Juliano Ferrer and Juliana Wingert (UFRGS), Cláudio Oliveira, Ricardo Britzke, Fábio Roxo, Bruno Melo and
Gabriel Silva (LBP), Vinícius Espíndola and Túlio Teixeira (MZUSP), Oscar Shibatta (MZUEL), Andressa
Oliveira, Francisco Severo and Thomaz Sinani (ZUFMS-PIS) for generously welcoming LFCT during museum
visits; Robert ‘Rob’ McLure for the pleasant late-night talks on Corydoras and for kindly reviewing the English
language of this paper; Celso Ikedo for the photographs of the holotype; Fernando Paiva and Lucas Blanco for
permitting the use and assistance in the image capture laboratory of the Universidade Federal de Mato Grosso do
Sul. The authors are supported by CNPq (LFCT: process #141061/2014-6) and FAPESP (WMO: grant # 2013/
22473–8).
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... Although our molecular results identified the nine lineages proposed by Alexandrou et al. (2011), we observed that lineages 4 and 5 were grouped together, as were lineages 6 and 9. Thus, a new division of the Corydoradinae into seven genera is proposed (Fig. 1), in the light of the phylogenetic analysis conducted herein and other cited studies plus the morphological data raised in previous studies (e.g. Britto 2003, Tencatt and Pavanelli 2015, Tencatt and Evers 2016, Tencatt and Ohara 2016a, b, Espíndola et al. 2018, Bono et al. 2019, 2020, 2022a,b, 2023, Bentley et al. 2021. Generic names are already available in the literature, as follows: Corydoras (lineage 1), Aspidoras (lineage 2), Scleromystax (lineage 3), Gastrodermus (lineages 4 and 5), Osteogaster (lineage 7), Brochis (lineage 8), and Hoplisoma (lineages 6 and 9). ...
... well-developed to conspicuously well-developed expansion, contacting pterotic-extrascapular in Brochis, Corydoras, Gastrodermus, and Osteogaster; infraorbital 2 variably contacting pterotic-extrascapular in A. lakoi and A. poecilus). SeeTencatt and Britto (2016),Tencatt and Evers (2016),Tencatt and Ohara (2016a),Tencatt et al. ( , 2019Tencatt et al. ( , 2022b, andEspíndola et al. (2018) for further information and illustrations on Hoplisoma. ...
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The family Callichthyidae, which comprises the subfamilies Corydoradinae and Callichthyinae, represents one of the largest families within the Siluriformes. Corydoradinae, the largest subfamily of Callichthyidae, alone accounts for >200 valid species, with new species being described frequently. This subfamily holds significant popularity among catfish enthusiasts worldwide, mainly because Corydoras are small, peaceful, and colourful fishes. Recognizing the existence of polyphyletic groups within Corydoradinae, the aim of this study was to construct a new phylogenetic hypothesis using genomic data (ultraconserved elements) and to re-evaluate the synonymized genera using the most recent morphological data. Our results supported the monophyly of Corydoradinae and identified seven distinct groups of species, each one with an associated preavailable generic name. These genera, namely Corydoras, Aspidoras, Scleromystax, Gastrodermus (resurrected), Osteogaster (resurrected), Brochis (resurrected), and Hoplisoma (resurrected), were all validated based on evidence derived from molecular and morphological analyses. A taxonomic key for the Corydoradinae genera is provided.
... Comprehensive studies attempting to understand the taxonomy and phylogenetic relationships of the species within Corydoras have been made (e.g., Alexandrou et al., 2011;Britto, 2003;Eigenmann & Eigenmann, 1890;Ellis, 1913;Gosline, 1940;Nijssen, 1970;Nijssen & Isbrücker, 1967, 1980a, 1983a, 1986. However, their taxonomy and phylogeny are still poorly known (Britto et al., 2007;Tencatt & Ohara, 2016a). ...
... Despite the wide geographic distribution of Corydoras in cisandean South America, its representatives predominantly occur in the Amazon basin, in which more than the half of the known species can be found (Tencatt & Ohara, 2016b). The rio Madeira basin, which flows into the rio Amazonas, is the world's richest drainage regarding the number of fish species (Jézéquel et al., 2020;Torrente-Vilara et al., 2013), and currently harbours 44 species of Corydoras, representing one quarter of the total species of the genus (Ohara et al., 2016;Tencatt & Evers, 2016;Tencatt & Ohara, 2016a, 2016b. ...
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... Currently, the family harbors more than 220 valid species, from which about 180 are included in Corydoras Lacépède, 1803(Fricke et al., 2023, making it one of the most species-rich genera of Siluriformes (Tencatt et al., 2023). Despite the comprehensive studies aiming to elucidate the taxonomy (e.g., Eigenmann, Eigenmann, 1890;Ellis, 1913;Gosline, 1940;Nijssen, 1970;Nijssen, Isbrücker, 1967, 1980a, 1983, 1986 and phylogenetic relationships (e.g., Britto, 2003;Alexandrou et al., 2011) of the species within Corydoras, taxonomists just scratched the surface on these fields of knowledge (Britto et al., 2007;Tencatt, Ohara, 2016a). ...
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A new species of Corydoras is described from the rio Xingu and rio Tapajós basins, Pará State, Brazil. The new species can be promptly distinguished from its congeners by the combination of the following features: (I) temporal sensory canal at sphenotic with two pores; (II) upper tooth plate of branchial arch with three or four series of teeth; (III) area at the corner of the mouth, ventral to the maxillary barbel, with a small, roughly triangular fleshy flap, not forming an elongated barbel-like structure; (IV) contact between posterior process of the parieto-supraoccipital and nuchal plate; (V) dark stripe transversally crossing the orbit, forming a mask-like blotch; (VI) absence of a distinct color pattern along midline of flank; (VII) dorsolateral body plates only with small, irregular, rounded or vertically elongated dark brown or black blotches; ground color of plates typically dusky but not forming large, conspicuous black patches; and (VIII) absence of a relatively large, conspicuous dark patch on anterior portion of dorsal fin.
... Currently, the family harbors more than 220 valid species, from which about 180 are included in Corydoras Lacépède, 1803(Fricke et al., 2023, making it one of the most species-rich genus within Siluriformes (Tencatt et al., 2022a(Tencatt et al., , 2023. Although a series of efforts have been made to elucidate the taxonomy (e.g., Eigenmann, Eigenmann, 1890; Ellis, 1913;Gosline, 1940;Nijssen, Isbrücker, 1967, 1980a, 1983, 1986Nijssen, 1970) and phylogenetic relationships (e.g., Britto, 2003;Alexandrou et al., 2011) of Corydoras, large knowledge gaps in these fields still remain (Britto et al., 2007;Tencatt, Ohara, 2016a). ...
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A new species of Corydoras is described from the rio Jutaí, Amazon basin, Brazil. The new species can be distinguished from its congeners by having the following features: (I) ventral surface of trunk entirely or almost entirely covered by small- to relatively large-sized coalescent platelets, forming a typical mosaic-like pattern; (II) large, arched dark brown or black patch extending from interopercle region to posterior process of parieto-supraoccipital, transversally crossing the orbit and forming a typical mask-like blotch; (III) absence of conspicuous dark markings on caudal fin; (IV) absence of longitudinal rows of dark blotches on flanks; (V) region of first dorsolateral body plate surrounding posterior process of parieto-supraoccipital clearly lighter than remaining portions of head, forming a V-shaped pattern in dorsal view; (VI) anterior portion of dorsal fin with a conspicuous dark patch; and (VII) anterior portion of dorsal-fin base with conspicuous concentration of dark brown or black chromatophores, forming a dark patch slightly darker than ground color of body. A discussion on the possible positive adaptive value of the color pattern is also provided.
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A new species of Corydoras is described from tributaries to the rio Araza, an affluent of the rio Inambari, itself a tributary to the rio Madre de Dios, rio Madeira basin in the Peruvian Amazon. The new species can be distinguished from its congeners by the following features: (I) absence of contact between the posterior process of the parieto-supraoccipital and the nuchal plate, (II) a single, large conspicuous dark brown or black blotch on anterodorsal portion of flank; blotch somewhat rounded to roughly diamond shaped, and (III) absence of dark blotches on fins. General comments on the identity of Corydoras aeneus are also provided.
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Aspidoras comprises 25 species currently considered as valid, being widely distributed in Brazil, occurring from the upper rio Paraná basin in São Paulo to coastal basins of Ceará. After Nijssen, Isbrücker’s review more than 40 years ago, no extensive work regarding the taxonomy of Aspidoras was conducted. Our paper presents a comprehensive taxonomic revision of the genus, based primarily on the extensive material that has been collected since then. Considering the new diagnosis plus the available phylogenetic data, A. pauciradiatus and A. virgulatus are transferred to Corydoras and Scleromystax, respectively. New synonymies are proposed: A. eurycephalus and A. taurus with A. albater; A. menezesi and A. spilotus with A. raimundi; and A. microgalaeus and A. marianae with A. poecilus. Additionally, a new species from the Araguaia and Paraguay river basins is described, which can be distinguished from its congeners by the morphology of its complex vertebra and infraorbital 1. Thereby, the number of valid species within Aspidoras was reduced from 25 to 18. Redescriptions for A. albater, A. belenos, A. depinnai, A. fuscoguttatus, A. lakoi, A. maculosus, A. poecilus, A. psammatides, A. raimundi, and A. velites are provided. An identification key to the species of Aspidoras is also provided.
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An expedition crowdfunded by aquarists to a region of the Brazilian state of Pará drained by the Tapajós and Xingu river basins resulted in the capture of five species of Corydoras from the rio Jamanxim basin, a tributary to the rio Tapajós, of which three could be confirmed as new and described herein. The new species can be promptly diagnosed from their congeners by the combination of features related to color pattern and osteology. Considering the gathered information on color patterns and morphology plus field observations, the new species are considered to compose two distinct Müllerian mimicry rings, with two of them forming a mimetic pair, while the third one forms a pair with a fourth non-identified species captured in the same expedition. An identification key to the species of Corydoras from the rio Tapajós basin is also provided.
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Crenuchinae is a subfamily of the fish family Crenuchidae distributed in the Amazon Basin with pronounced sexual dimorphism and exuberant colour patterns. Recent fieldwork in the tributaries of the Rio Aripuanã drainage, a large tributary of the Rio Madeira (Amazon Basin), resulted in the discovery of two distinctive, undescribed species of the crenuchin genus Poecilocharax, which are formally described herein, combining morphological and molecular data. These are the first representatives of Crenuchinae discovered after a gap of 57 years and the first records of Poecilocharax from the tributaries of the right bank of the Rio Amazonas draining the Brazilian crystalline shield. Based on a taxonomic review including all species of the subfamily, we provide an expanded morphological diagnosis for Crenuchinae. This now includes characteristics related to the lateral-line canals of head and body, the number of dorsal-fin rays and sexually dimorphic traits. In addition, we review previous characteristics used to diagnose Crenuchus and Poecilocharax, providing comments on their polarity and distribution across the subfamily. A dichotomous key is provided for the first time for species of Crenuchinae.
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This study aims to provide an annotated list of the type-material housed in the fish collection of the Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (NUP), Universidade Estadual de Maringá, Paraná, Brazil. NUP’s fish type collection hosts type-material of 157 species, distributed in 503 lots (11 holotypes and 492 lots of paratypes) totalling 2,915 specimens. For each species, catalog numbers of all available lots are provided, and for each lot, total number of specimens, range of variation of standard length, number of cleared and stained specimens (when any), locality data, collectors, and date of collection, are provided.
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This paper contains descriptions and figures of two new species of Corydoras, C. maculifer from Brazil and C. panda from Peru. The relationships of the new species with other species of Corydoras are discussed. Corydoras maculifer new species (figs.
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A new species of Corydoras is described from the río Madre de Dios basin, Peru. The new species can be distinguished from its congeners by presenting the following features: a longitudinal black stripe along midline of flank; mesethmoid short, with anterior portion poorly developed; serrations on posterior margin of pectoral spine directed towards the tip of the spine; dorsal fin with the region of the first branched ray, including membrane, with concentration of black pigmentation, the remaining areas with irregular black blotches; absence of a vertically elongated black blotch across the eyes; conspicuously rounded moderately-developed black spots on the snout; and ventral expansion of infraorbital 1 moderately developed.
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Two new species of Corydoras are described from the rio Madeira basin, Brazil. The intermediate long-snouted new species can be distinguished from its congeners by presenting the following combination of features: posterior margin of dorsal-fin spine with laminar serrations directed towards the origin of the spine; presence of two longitudinal black stripes on flanks; anterior portion of dorsal fin with sparse black chromatophores, not forming any conspicuous pattern; absence of a conspicuous black marbled coloration pattern on head; black spots on caudal fin, some spots arranged, forming transversal bars; and brownish dorsal-fin spine. The short-snouted new species can be distinguished from its congeners by the following combination of features: short mesethmoid; posterior laminar expansion of infraorbital 2 very reduced, not in contact with compound pterotic; two or three longitudinal black stripes on flanks; absence of an oblique or vertical black blotch across the eye; anterior portion of dorsal fin with sparse black chromatophores, not forming any conspicuous pattern; and ventral surface of trunk naked or covered by sparse platelets.
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A new species of Corydoras is described from the rio Araguaia basin, Goiás, Brazil. The new species can be distinguished from its congeners by presenting the following features: infraorbital 1 with very large ventral laminar expansion; infraorbital 2 contacting compound pterotic; flanks densely covered by irregular black spots; and ventral surface of trunk densely covered by coalescent relatively well-developed platelets. It is also discussed the possibility that C. araguaiaensis comprehends a complex of species.
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Abstract A fully resolved cladogram for 19 species in the Charis cleonus group of riodinid butterflies, which have closely parapatric ranges throughout the Amazon basin, is used to derive an area cladogram for the region. This represents the first comprehensive species-level analysis using insects and results in a hypothesis of Amazonian area relationships that is the most detailed to date. The Charis area cladogram is interpreted as supporting an historical vicariant split between the Guianas and the remainder of the Amazon and then between the upper and lower Amazon. The latter two clades can be further divided into the six most widely recognized areas of endemism and even smaller endemic centers within these, some of which, especially along the Madeira and lower Amazon Rivers, have never been previously hypothesized for butterflies. The overall pattern of historical interrelationships indicated is Guiana + ((Rondônia + (Pará+ Belém)) + (Imeri + (Napo + Inambari))). The area relationships for riodinid butterflies show substantial congruence with those presented from the literature for amphibians, reptiles, birds, primates, rodents, and marsupials, suggesting a common vicariant history for these organisms. A summary area cladogram generated by combining area cladograms for all the aforementioned groups of organisms indicated the pattern of historical interrelationships to be (Guiana + (Rondônia + (Pará+ Belém))) + (Imeri + (Napo + Inambari)). Charis cleonus group species distributions are noticeably larger around the upland periphery of Amazonia and smaller in the central and lower regions. A significant positive correlation between the proportion of range area above 100 m and total range size for each species is used to suggest that past sea-level rises may explain smaller range sizes in low-lying regions and that riverine barriers have been important in shaping the current distribution of C. cleonus group species.
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Geophagus sveni n. sp. and G. neambi n. sp. are described from the Rio Tocantins drainage of Brazil. Geophagus sveni and G. neambi differ from some of its congeners by the lack of head markings. G. sveni is distinguished from the species lacking head markings by the presence of five faint undivided vertical bars, proeminent mid-lateral blotch, and by the caudal fin vertically clear and black barred; G. neambi differs from the species lacking head markings by the possession of eight or nine vertical, parallel bars along the flank, the bar containing mid-lateral spot bifurcate above and below midlateral blotch and by the caudal fin bearing rounded white spots. Geophagus sveni differs from the sympatric and syntopic Geophagus neambi by the presence of five faint vertically bars (vs. eight or nine conspicuous dorso-ventral bifurcated vertically bars).