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240
Accepted by J. Armbruster: 24 Jun. 2016; published: 4 Aug. 2016
ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN
1175-5334
(online edition)
Copyright © 2016 Magnolia Press
Zootaxa 4147 (3): 240
–
246
http://www.mapress.com/j/zt/
Article
http://doi.org/10.11646/zootaxa.4147.3.2
http://zoobank.org/urn:lsid:zoobank.org:pub:25C68B8B-1A7C-4B9C-9B82-23482005D59D
A new Otocinclus (Siluriformes: Loricariidae: Hypoptopomatinae)
from the Rio Juruena Basin, central Brazil
ALEXANDRE CUNHA RIBEIRO
1
& PABLO LEHMANN A.
2
1
Departamento de Biologia e Zoologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Av. Fernando Corrêa da
Costa 2367, 78060-900, Cuiabá, MT, Brazil. E-mail: alexandrecunharibeiro@gmail.com
2
Laboratório de Ictiologia, Universidade do Vale do Rio dos Sinos, Av. Unisinos 950, 93022-000 São Leopoldo, RS, Brazil.
E-mail: pablole@unisinos.br
Abstract
A new species of Otocinclus (Loricariidae) is described from the Rio Juruena, a right bank tributary of the Rio Tapajós
system in Mato Grosso State, central Brazil. The new taxon can be distinguished from its congeners by the possession of
an ocular operculum and by a complete lateral line. Additionally, the new species is distinguished by having a dorsal trunk
coloration composed of a set of distinct oval dark blotches and by a caudal spot.
Key words: Catfish, taxonomy, systematics, biodiversity, Neotropical Region
Introduction
The loricariid subfamily Hypoptopomatinae includes 22 genera, including Otocinclus Cope, 1871, with 19 species
(Eschmeyer et al., 2016). Subsequent to the revision of Otocinclus by Schaefer (1997), five species were described:
O. tapirape Britto & Moreira, 2002; O. mimulus Axenrot & Kullander, 2003; O. cocama Reis, 2004; O. batmani
Lehmann, 2006; and O. mangaba Lehmann et al. (2010a). Additional papers dealing with the taxonomy of
Otocinclus includes that of Lehmann et al. (2010b), which resurrected O. arnoldi of the La Plata basin from the
synonymy with O. flexilis, which was described from the Rio Jacuí drainage. Lehmann et al. (2010b) also provided
a reappraisal of the Otocinclus phylogeny, in which the genus is considered a natural group corroborating previous
analyses (Schaefer, 1991; Britto & Moreira, 2002; and Axenrot & Kullander, 2003). Despite the evidence of some
well-supported monophyletic species groups, Lehmann et al. (2010b) pointed out that several species are included
in poorly resolved clades, suggesting that additional studies on taxonomy as well as on phylogenetic relationships
within the group are needed. Otocinclus currently represents the third most diverse genus among all
Hypoptopomatines, after Hisonotus and Parotocinclus, two genera recovered as paraphyletic by morphological and
molecular studies (Lehmann et al, 2013 and Cramer et al, 2011; Lehmann, 2006; Gauger & Buckup 2005;
Chiachio et al, 2008). Therefore, Otocinclus could represent the largest monophyletic clade within the
Hypoptopomatinae. This paper describes a new Otocinclus species from the Rio Juruena, a right bank tributary of
the Rio Tapajós system in Mato Grosso State, central Brazil.
Material and methods
Measurements were made point-to-point, to the nearest 0.1 mm with digital calipers. Methodology and
terminology for measurements follow Boeseman (1968: 26–27, fig. 5) including the preanal length (taken from
snout tip to anal-fin origin), and the following three additional measurements suggested by Armbruster & Page
(1996): anal width (body width at the insertion of the first anal-fin ray); folded dorsal-fin length (the length of the
depressed dorsal fin, measured from the posterior edge of the nuchal plate), and the snout-opercle length (from the
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A NEW OTOCINCLUS FROM THE RIO JURUENA BASIN, BRAZI L.
snout tip to the postero-dorsal edge of the bony opercle). Plate counts and nomenclature follow the schemes of
serial homology proposed by Schaefer (1997). Counts follow Bockmann & Ribeiro (2003). All morphometric and
meristic data, including premaxillary and dentary tooth counts, were taken from the left side. Morphometric data
were expressed as percent of standard length (SL), except subunits of the cephalic region, which were expressed in
percent of head length. Anal width was also expressed as percent of cleithral width. Institutional abbreviations
follow Fricke & Eschmeyer (2012). Comparative material examined was listed in Lehmann et al. (2010b).
Otocinclus juruenae
(Fig. 1).
Holotype. MZUSP 120361, female, 29.6 mm SL, Brazil, Mato Grosso, Juara, Tapajos basin, Rio Juruena drainage,
bridge over Rio São João da Barra, (10
0
18', 46,0”S/ 57
0
38' 44,0”W), Fábio Rosa & Willian Assunção, August, 6,
2007.
Paratypes. CPUFMT 839, 18 (22.3–33.0 mm SL) and MCP 49446, 3 (27.4–29.4 mm SL)+2 CS (26.2–27.8
mm SL) collected with holotype.
FIGURE 1. Holotype of Otocinclus juruenae, MZUSP 120361, female, 29.6 mm SL. Lateral (A) dorsal (B) and ventral (C)
views.
Diagnosis. The new species differs from all congeners (except Otocinclus cocama) by having a complete lateral
line, without gap plates. Otocinclus juruenae differs from O. bororo, O. caxarari, O. hoppei, O. huaorani, O.
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Zootaxa 4147 (3) © 2016 Magnolia Press
macrospilus, O. mariae, O. mura, O. vestitus, and O. vittatus (previously assigned by Schaefer, 1997 to the “orbis”
clade) as well as O. batmani and O. cocama by having an iris operculum (vs. iris operculum absent). It is further
distinguished from all Otocinclus except O. flexilis and O. xakriaba by the lateral trunk coloration consisting of a
series of three to four diffuse pigment blotches without a distinct midlateral stripe (vs. trunk with distinct midlateral
stripe).
Description. Morphometric and meristic data in Table 1 and 2, respectively. Largest specimen examined 33.0
mm SL. Dorsal profile of body in lateral view gently arched from snout tip to dorsal-fin insertion; slightly concave
to straight along base of dorsal fin; straight between dorsal fin and caudal peduncle and slightly concave along
caudal peduncle to caudal-fin base. Ventral profile of body in lateral view straight to slightly concave along ventral
margins of rostral plates, between snout tip and posteroventral margin of opercle; slightly convex to straight
between that point and pelvic-fin insertion, along abdomen; straight to slightly concave between ventral fin and
slightly concave from anal-fin insertion to caudal-fin base. Caudal peduncle oval to slightly rectangular in cross-
section, longer along its dorsoventral axis. Greatest body depth at dorsal-fin origin. Least body depth at caudal
peduncle. Greatest body width at pectoral-fin insertion, trunk gradually tapering from cleithrum to caudal-fin base.
Table 1. Morphometrics of Otocinclus juruenae. sd = standard deviation.
Character Holotype Range Mean sd N
Standard length (mm) 29.6 22.3–33.0 26.5 15
Percent of standard length
Predorsal length 46.4 45.8–50.5 47.9 1.2 15
Preanal length 63.4 61.2–66.5 63.6 1.4 15
Head length 35.0 35.0–38.1 36.4 1.0 15
Cleithral width 22.1 21.8–23.8 22.7 0.6 15
Dorsal-fin spine length 25.3 23.2–27.0 25.1 1.1 14
Folded dorsal-fin length 26.0 23.8–27.8 25.9 1.2 16
Base of dorsal-fin length 12.3 10.7–13.5 12.2 0.6 16
Thorax length 22.1 22.1–25.0 24.2 0.7 15
Pectoral-fin spine length 23.5 22.9–27.3 24.8 1.3 15
Abdomen length 19.6 17.5–19.9 18.9 0.8 15
Pelvic-fin spine length 16.4 15.9–19.0 17.6 1.0 15
Postanal length 32.7 28.3–32.7 30.4 1.4 15
Caudal-peduncle depth 10.3 10.1–11.9 10.8 0.4 15
Anal width 11.8 11.8–14.4 13.0 0.7 15
Snout-opercle length 26.9 25.3–27.6 26.7 0.7 15
Percent of head length
Head width 59.8 54.2–61.9 59.3 2.1 15
Head depth 51.6 45.1–56.9 52.5 3.7 15
Snout length 49.1 45.2–49.2 47.7 1.1 15
Interorbital width 45.0 40.9–47.0 44.8 1.9 15
Orbital diameter 19,4 18.1–21.4 19.7 0.8 15
Percent of cleithral width
Anal width 53.4 53.4–62.6 57.2 2.8 15
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A NEW OTOCINCLUS FROM THE RIO JURUENA BASIN, BRAZI L.
Head broad, elliptical anteriorly. Snout tip anteriorly pronounced. Median elongated bulge associated with
mesethmoid from snout tip to transverse line between nares inconspicuous, providing flat aspect between nares.
Interorbital region slightly concave. Eyes laterally placed, visible from ventral view. Iris with small semicircular
operculum (iris diverticulum) extending from dorsal margin of iris and covering pupil. Oral disk (lips) elliptical,
broad, reaching to vertical through anterior orbital margins, not reaching to pectoral girdle. Lower lip covered with
numerous similarly-sized papillae. Oral disk with fringed margins, fringes formed by well-developed, elongated
papillae. Maxillary barbel present. Buccal papilla present, moderately developed. Teeth slender, bifid, with larger
medial cusp and smaller lateral cusp minute and pointed.
Body entirely covered by plates, except for ventral surface of head and insertions of pectoral and pelvic fins.
Abdomen with paired series of six to eight large, sickle-shaped lateral plates; median plates in one row and seven to
eight plates, extending posteriorly beyond lateral abdominal plates series to middle of branched pelvic-fin rays;
pre-anal shield well developed, continuous with median abdominal plates. Plates and odontodes of head and body
not arranged in crests, keels, or conspicuous rows. Tip of parieto-supraoccipital without conspicuous tuff of
enlarged odontodes, odontodes just slightly enlarged. Odontodes slightly enlarged at rostral plates. Rostral and
cheek plates limiting ventral margin of snout. Pectoral girdle exposed ventrally and coved with odontodes.
Abdomen plated. Lateral line complete, without a gap lacking sensory pores 2). Lateral-line pores small and
inconspicuous.
Tip of adpressed pectoral-fin spine reaching to about anterior one third of pelvic-fin. Odontodes of distal
portion of pectoral-fin spine conspicuously larger than remaining pectoral-fin odontodes. Tip of adpressed pelvic-
fin spine reaching to anal-fin origin. Dorsal-fin insertion at vertical just anterior to insertion of pelvic fin. Dorsal-
fin spinelet V-shaped, dorsal-fin spine locking mechanism functional. Insertion of anal fin at vertical just behind
posterior tip of dorsal fin. Caudal-fin margin concave, upper caudal-fin lobe slightly longer than lower caudal-fin
lobe.
TABLE 2. Meristics of Otocinclus juruenae.
Color in alcohol. Ground color slightly creamy to pale yellow. Even sprinkling of melanophores between
supraoccipital and origin of dorsal fin; trunk on dorsal-fin base with five or six cluster of concentrated
melanophores, follow by nine or ten spots with pigment concentrated in oval shape on dorsal series plates from
dorsal-fin base to first dorsal procurrent caudal-fin ray. Unbranched caudal-fin ray with three or four distinct
blotches in dorsal view.
Character Holotype Range Mode N
Dorsal plates 23 22–24 23 10
Mid-dorsal plates 17 16–18 16 10
Median plates 24 24–26 24 10
Midi-ventral plates 19 19–19 19 10
Ventral plates 20 20–21 20 10
Predorsal plates 3 3–3 3 10
Dorsal plates between posterior dorsal-fin ray and caudal-fin mambrane 16 14–16 16 10
Dorsal plates within dorsal-fin interradial membrane 4 3–4 4 10
Ventral plates within anal-fin interradial membrane 3 3–3 3 10
Ventral plates from end of anal fin to caudal–fin membrane 12 11–13 12 10
Dorsal-fin branched rays 7 7–7 7 10
Pectoral-fin branched rays 6 6–6 6 10
Pelvic-fin branched rays 5 5–5 5 10
Anal-fin branched rays 5 5–5 5 10
Caudal-fin branched rays 14 14–14 14 10
Premaxillary teeth 17 16–19 17 10
Dentary teeth 14 13–17 13 10
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Head and trunk with diffuse sprinkling of melanophores, without distinct midlateral stripe, pigment especially
concentrated in region immediately posterior to orbit and area dorsal to margin of opercle. Side of trunk composed
of superficial and deep-lying melanophores arranged in distinct clusters along length of trunk between opercle and
caudal fin; such clusters, in turn, concentrated into three to four diffuse blotches along length of trunk. Pigment
between blotches present, inconspicuous, not appearing as stripe of uniform width and intensity. Caudal spot oval-
shaped, narrow (not reaching to the dorsal and ventral margins on the caudal peduncle) intensely pigmented,
extending posteriorly just along proximal half of median branched caudal-fin rays as intense concentration of
melanophores, rectangular in shape. Caudal-fin rays with scattered melanophores arranged in parallel pair of
diffuse pigment bands, anterior band located about midway along length of fin, posterior band located near
posterior fin margin. Dorsal fin with melanophores along entire length of spine arranged in four to five blotches;
pigment on branched rays concentrated in two to three faint bands, posterior one with melanophores more
concentrated on ray ramifications; interradial membranes unpigmented. Anal fin unpigmented. Pectoral fin with
even distribution of melanophores along pectoral spine; branched rays and interradial membranes unpigmented.
Pelvic fin with few melanophores arranged in one or two blotches on distal two-thirds of unbranched ray,
interradial membranes and branched rays unpigmented. Ventral surface of head and body unpigmented, except for
numerous scattered melanophores on ventrolateral margin of pectoral girdle.
Distribution. Know only from its type locality in the Rio Juruena, central Brazil (Fig. 2).
Etymology. Named after the Rio Juruena, a right bank tributary of the Rio Tapajós basin where the type
material was collected. An adjective.
FIGURE 2. Type locality of Otocinclus juruenae. Shaded area at left encompasses the political boundaries of Mato Grosso
state, central Brazil.
Discussion
The new species herein described has a general color pattern more similar to a group of species with a dorsal trunk
coloration composed of a set of distinct oval dark blotches extending from just posterior to the dorsal fin to the base
of the upper caudal-fin lobe. These species include O. macrospilus, O. mariae and O. hoppei. However, in O.
macrospilus and O. hoppei the caudal spot is completely detached from the lateral stripe. Despite similarity to O.
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A NEW OTOCINCLUS FROM THE RIO JURUENA BASIN, BRAZI L.
mariae in having the caudal spot continuous with the lateral stripe, the lateral stripe is much narrower at the caudal-
fin base in O. mariae than in O. juruenae, in which it is almost as thick as the caudal spot. Otherwise, the caudal
spot in O. juruenae is positioned anterior to the caudal-fin membrane, and is limited to the plated region of the
caudal peduncle (Fig. 3). In the set of species mentioned above, the caudal spot extends over the caudal-fin
membrane and reaches both the dorsal and ventral margins of the caudal peduncle (fig. 2 in Lehmann et al., 2010a).
In most Otocinclus species, the lateral line is not complete along the entire median plate series, with a gap
composed of one or more median plates in which the lateral line is absent (Schaefer, 1997). A complete lateral line
(and thus the absence of a gap) as observed in O. juruenae is rare among Otocinclus species, being otherwise only
observed in O. cocama.
Otocinclus juruenae represents the first record of Otocinclus in the Rio Tapajós basin, a large area
encompassing 489,626 km
2
draining the upland Brazilian crystalline shield under the Amazonian biome (Goulding
et al. 2003). This illustrates the lack of basic biodiversity data in such a large area of the Amazon forest under
increasing agriculture, mining and hydroelectric power plant pressures. Without a concentrated effort in
prospecting and describing such hidden biodiversity, many species could become extinct before being properly
described.
FIGURE 3. Detail of the caudal-fin color pattern of Otocinclus juruenae, holotype.
Acknowledgments
We thank Flávio C.T. Lima for calling our attention to this new species housed in CPUFMT and for additional
useful suggestion. Roberto E. Reis provided a critical review and useful suggestions. ACR and PLA are partially
funded by the Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq (Processes #405815/
2013-1 and #483060/2013-5, respectively).
References
Armbruster, J.W. & Page, L.M. (1996) Redescription of Aphanotorulus (Teleostei: Loricariidae) with description of one new
species, A. ammophilus, from the Río Orinoco Basin. Copeia, 1996 (2), 379–389.
http://dx.doi.org/10.2307/1446854
Axenrot, T.E. & Kullander, S.O. (2003) Corydoras diphyes (Siluriformes: Callichthyidae) and Otocinclus mimulus
(Siluriformes: Loricariidae), two new species of catfishes from Paraguay, a case of minetic association. Ichthyological
Exploration of Freshwaters, 14, 249–272.
Britto, M.R. & Moreira, C.R. (2002) Otocinlus tapirape: a new Hypoptopomatinae catfish from central Brazil (Siluriformes:
Loricariidae). Copeia 2002, 1063–1069.
RIBEIRO & L EHMANN
246
·
Zootaxa 4147 (3) © 2016 Magnolia Press
http://dx.doi.org/10.1643/0045-8511(2002)002[1063:OTANHC]2.0.CO;2
Bockmann, F.A. & Ribeiro, A.C. (2003) Description of a new suckermouth armored catfish of the genus Pareiorhina
(Siluriformes: Loricariidae), from southeastern Brazil. Ichthyological Exploration of Freshwaters, 14, 231–242.
Boeseman, M. (1968) The genus Hypostomus Lacépède, 1803, and its Surinam representatives (Siluriformes, Loricariidae).
Zoologische Verhandelingen, 99, 1–89, Pls. 1–18.
Chiachio. M.C., Oliveira. C. & Montoya-Burgos, J.I. (2008) Molecular systematic and historical biogeography of the armored
Neotropical catfishes Hypoptopomatinae and Neoplecostominae (Siluriformes: Loricariidae). Molecular Phylogenetics
and Evolution, 49, 606–617.
http://dx.doi.org/10.1016/j.ympev.2008.08.013
Cramer, C.A, Bonatto, S.L & Reis, R.E. (2011) Molecular phylogeny of the Neoplecostominae and Hypoptopomatinae
(Siluriformes: Loricariidae) using multiple genes. Molecular Phylogenetics and Evolution, 59, 43–52.
http://dx.doi.org/10.1016/j.ympev.2011.01.002
Eschmeyer, W.N., Fricke, R. & van der Laan, R. (2016) Catalog of fishes: genera, species. Avaailable from: http://
www.calacademy.org/scientists/projects/catalog-of-fishes (accessed 15 Jan. 2016)
Fricke, R. & Eschmeyer, W.N. (2016) A guide to fish collections in the Catalog of fishes. Online version, updated 2 June 2016.
Internet publication, San Francisco (California Academy of Sciences).
Gauger, M.F.W. & Buckup, P.A. (2005) Two new species of Hypoptopomatinae from the rio Paraíba do Sul basin, with
comments on the monophyly of Parotocinclus and the Otothyrini (Siluriformes: Loricariidae). Neotropical Ichthyology, 3:
509–518.
Goulding, M., Barthem, R. & Ferreira, E. (2003) The Smithsonian atlas of the Amazon. Smithsonian Books, Washington and
London. 253p.
Lehmann, P.A. (2006) Anatomia e relações filogenéticas da família Loricariidae (Ostariophysi: Siluriformes) com ênfase na
subfamília Hypoptopomatinae. Unpublished Phd Thesis, Pontifícia Universidade Católica do Rio Grande do Sul.
Lehmann, P.A., Mayer, F. & Reis, R.E. (2010a) A new species of Otocinclus (Siluriformes: Loricariidae) from the Rio Madeira
drainage, Brazil. Copeia, 2010, 635–639.
Lehmann, P.A., Mayer, F. & Reis, R.E. (2010b) Re-validation of Otocinclus arnoldi Regan and reappraisal of Otocinclus
phylogeny (Siluriformes: Loricariidae). Neotropical Ichthyology, 8, 57–68.
Lehmann, P.A., Braun, B.K., Pereira, E.H.L. & Reis, R.E. (2013) A new species of the Hypoptopomatinae catfish
Parotocinclus (Siluriformes, Loricariidae), from the headwaters of the Rio Jequitinhonha, Brazil. Copeia, 2013, 435–440.
Schaefer, S.A. (1991) Phylogenetic analysis of the loricariid subfamily Hypoptopomatinae (Pisces: Siluroidei: Loricariidae),
with comments on generic diagnoses and geographic distribution. Zoological Journal of the Linnean Society, 102, 1–41.
Schaefer, S.A. (1997) The neotropical cascudinhos: systematics and biogeography of the Otocinclus catfishes (Siluriformes:
Loricariidae). Proceedings of the Academy of Natural Sciences of Philadelphia, 148, 1–120.
