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A New Genus and Species of Hypoptopomatine Catfish (Siluriformes: Loricariidae) from the Upper Rio São Francisco Basin, Brazil

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Plesioptopoma curvidens is a new genus and species of hypoptopomatine loricariid from the upper Rio Paraopeba, a tributary to the Rio São Francisco in southeastern Brazil. Plesioptopoma is attributed to the hypoptopomatines based on five shared synapomorphies, and differs from all remaining members of the subfamily by having the premaxilla and dentary tooth series strongly curved mesially, in such a way that the mesial portion of the tooth series in both sides are turned and run parallel to each other, the caudal peduncle distinctly quadrangular in cross-section, and the anterior margin of the snout devoid of dermal plates.
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A New Genus and Species of Hypoptopomatine Catfish (Siluriformes:
Loricariidae) from the Upper Rio São Francisco Basin, Brazil
Author(s) :Roberto E. Reis, Edson H. L. Pereira, and Pablo Lehmann A.
Source: Copeia, 2012(1):6-11. 2012.
Published By: The American Society of Ichthyologists and Herpetologists
DOI: http://dx.doi.org/10.1643/CI-11-068
URL: http://www.bioone.org/doi/full/10.1643/CI-11-068
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A New Genus and Species of Hypoptopomatine Catfish
(Siluriformes: Loricariidae) from the Upper Rio Sa˜o Francisco Basin, Brazil
Roberto E. Reis
1
, Edson H. L. Pereira
1
, and Pablo Lehmann A.
2
Plesioptopoma curvidens is a new genus and species of hypoptopomatine loricariid from the upper Rio Paraopeba, a
tributary to the Rio Sa˜o Francisco in southeastern Brazil. Plesioptopoma is attributed to the hypoptopomatines based on
five shared synapomorphies, and differs from all remaining members of the subfamily by having the premaxilla and
dentary tooth series strongly curved mesially, in such a way that the mesial portion of the tooth series in both sides are
turned and run parallel to each other, the caudal peduncle distinctly quadrangular in cross-section, and the anterior
margin of the snout devoid of dermal plates.
KNOWLEDGE about the diversity among the Neo-
tropical cascudinhos of the subfamily Hypoptopo-
matinae is increasing at a fast rate in the last two
decades, with eight of the 19 genera currently known having
been described in this period. Despite the intense ongoing
effort toward uncovering the hidden diversity of hypopto-
pomatines, new taxa not referable to any of the known
genera are still being discovered by fish taxonomists in
intensively sampled areas such as the upper Rio Sa˜o
Francisco basin.
The fish described herein is unambiguously identified as
a member of the Hypoptopomatinae, despite sharing some
features with the Neoplecostominae, based on its peculiar
morphology and anatomy, being at the same time readily
distinguishable from all other members of the subfamily.
Below we diagnose the new taxon describing a new genus
and species, and discuss the characters used to place it
within the Hypoptopomatinae.
MATERIALS AND METHODS
Methodology and terminology for linear measurements
follow Pereira et al. (2007), with the addition of internarial
width, measured between the mesial margins of both
anterior nares. Morphological measurements were made
point-to-point to the nearest 0.1 mm with digital calipers
under a dissecting scope. Body plate counts and nomencla-
ture follow Schaefer (1997). Measurements of bilaterally
symmetrical features were made on the left side of the body
whenever possible. Morphometric data are expressed as
percents of the standard length (SL), except subunits of the
cephalic region which were expressed as percents of head
length (HL). Morphometric data are presented separately
for two classes of body length in order to allow proper
comparisons of small and large specimens. Vertebral counts
include all vertebrae, including the five centra modified into
the Weberian apparatus, with the compound caudal cen-
trum (PU1+U1) counted as one element. Vertebral elements
were counted in cleared-and-stained specimens only. Oste-
ological examinations were performed on specimens cleared
and double-stained for bone and cartilage (CS) according to
the procedure of Taylor and Van Dyke (1985). Institutional
abbreviations for specimens examined are those listed in
http://www.asih.org/node/204. Specimens examined for
this study are those listed in Lehmann (2006) and Pereira
(2009), with the addition of those listed below under Material
Examined.
Plesioptopoma, new genus
Type species.—Plesioptopoma curvidens, new species
Diagnosis.—Distinguished from non-Hypoptopomatinae lor-
icariids by having the ventral surface of the coracoid with an
exposed area supporting a few odontodes laterally, close to
the pectoral-fin insertion (Fig. 1), and, except from Kro-
nichthys, by having the odontodes on the ventral surface of
the pelvic-fin unbranched ray distinctly bent and turned
mesially (Fig. 2). Distinguished from all hypoptopomatines,
except Parotocinclus prata, by having the premaxilla and
dentary tooth series strongly curved mesially, in such a way
that the mesial portion of the tooth series in both sides are
turned and run parallel to each other (Fig. 3; vs. tooth series
straight or slightly curved). It is also distinguished from the
remaining hypoptopomatines, except Pseudotocinclus,by
having the caudal peduncle distinctly quadrangular in
cross-section (vs. caudal peduncle ovoid in cross-section),
and except from Gymnotocinclus by having the anterior
margin of the snout devoid of dermal plates (Fig. 4; vs.
anterior margin of snout plated).
Etymology.—The genus name Plesioptopoma is a combination
of the Greek plesion, meaning primitive, and optopoma, the
root of Hypoptopoma, type-genus of the subfamily, in
reference to the putative basal position of the new taxon
among the hypoptopomatines.
Plesioptopoma curvidens, new species
Figure 1, Table 1
Holotype.—MCP 46286, 82.8 mm SL, male, Brazil, Minas
Gerais, Cristiano Otoni, Rio Paraopeba, upper Rio Sa˜o
Francisco drainage, at old bridge ca. 100 m W of highway
BR-040, 20u499110S, 043u489470W, R. E. Reis, E. H. L. Pereira,
and P. Lehmann, 8 October 2004.
Paratypes.—MCP 36861, 8 (28.8–74.7 mm SL) +2 CS (29.2–
38.0 mm SL), AMNH 253202, 3 (29.0–36.5 mm SL), collected
1
Laborato´ rio de Sistema´tica de Vertebrados, Pontifı´cia Universidade Cato´ lica do Rio Grande do Sul, Av. Ipiranga, 6681, Caixa Postal 1429,
90619-900 Porto Alegre, RS, Brazil; E-mail: (RER) reis@pucrs.br; and (EHLP) ehlpereira@gmail.com.
2
Laborato´ rio de Ictiologia, Universidade do Vale do Rio dos Sinos, Av. Unisinos, 950, 93022-000 Sa˜o Leopoldo, RS, Brazil; E-mail:
pablole@unisinos.br.
Submitted: 13 May 2011. Accepted: 19 September 2011. Associate Editor: S. A. Schaefer.
F2012 by the American Society of Ichthyologists and Herpetologists DOI: 10.1643/CI-11-068
Copeia 2012, No. 1, 6–11
with the holotype; MNRJ 21426, 3 (53.2–79.3 mm SL) +1CS
(59.3 mm SL), same locality as the holotype, F. A. G. Melo,
P. A. Buckup, and M. R. S. Melo, 24 February 2000.
Diagnosis.—Same as for genus.
Description.—Proportional measurements and counts in
Table 1. Medium-sized loricariid with standard length of
adult measured specimens 53.2–82.8 mm SL. Body elongate
and moderately depressed, progressively tapering from
cleithrum to end of caudal peduncle. Dorsal profile of body
gently convex, rising from snout tip to origin of dorsal fin
and then descending to end of caudal peduncle. Greatest
body depth at dorsal-fin origin. Least body depth at
shallowest part of caudal peduncle. Head and predorsal
region without conspicuous crests; dorsal and ventral series
on lateral plates strongly bent posteriorly and with distinct
series of odontodes forming conspicuous crests. Trunk
horizontally oval in cross-section, caudal peduncle strongly
flattened dorsally and ventrally becoming approximately
hexagonal at anal-fin level and quadrangular before the
caudal fin. Ventral profile almost straight between snout tip
and pelvic girdle, slightly elevating posteriorly along anal-
fin base, almost straight along caudal peduncle. Lateral-line
canal in median series complete, pored tube visible from
compound pterotic to last plate in middle lateral series. Mid-
dorsal and mid-ventral series of lateral plates incomplete,
terminating 6–10 plates before the caudal fin. Dorsal surface
of body covered by plates except for small naked area
around dorsal-fin base and opening of swimbladder capsule
posteroventrally to compound pterotic. Ventral surface of
head around lips, portion between pelvic-fin insertions
and around anal fin naked. Abdomen covered by small,
embedded platelets, irregularly arranged from pectoral
girdle to insertion of pelvic fins and between pelvic-fin
bases. Lateral abdominal plates absent. Small portion of
Fig. 1. Plesioptopoma curvidens, MCP 46286, holotype, 82.8 mm SL, male, Brazil, Minas Gerais, Cristiano Otoni, Rio Paraopeba, upper Rio Sa˜o
Francisco drainage, at old bridge ca. 100 m W of highway BR-040, 20u499110S, 043u489470W. White arrow points to exposed area of coracoid.
Reis et al.—New loricariid genus 7
pectoral girdle exposed ventrally next to pectoral-fin
insertion; sometimes one, usually few odontodes attached
to coracoid visible externally; girdle covered medially by
skin and abdominal platelets. Arrector fossa completely
open.
Head moderately depressed; broadly round in dorsal
view with snout slightly squarish. Interorbital space straight
or slightly convex; superior margin of orbit not elevated.
Parieto-supraoccipital slightly elevated posterior to orbit.
Posterior tip of parieto-supraoccipital without enlarged or
raised odontodes even in smaller individuals. Snout tip with
large area of naked skin, devoid of odontodes. Rostral and
anterior postrostral plates absent; two large postrostral plates
present anterior to preoperculum. Preoperculum exposed;
canal-bearing lateral cheek plate with unbranched canal.
Adult specimens with well-developed soft fleshy tissue
extending along snout tip and ventral portion of head. Eye
small, dorsolaterally placed. Iris operculum absent or very
small. Nostrils at posterior terminus of pair of elongate,
shallow depressions beginning close to snout tip, ovoid,
slightly longer than wide, positioned closer to anterior
margin of orbit than to snout tip. Oral disk roughly circular;
lips well developed, occupying most of ventral surface of
head. Lower lip short, extending posteriorly to end of canal-
bearing lateral cheek plate or between that point and
anterior margin of pectoral girdle, upper lip wide and fleshy.
Both lips densely covered by minute papillae; decreasing in
size toward edge in lower lip. Posterior edge of lower lip
smooth or slightly fringed. Maxillary barbel short, mostly
adnate to lower lip and with very small free portion distally.
Tooth-bearing cup of both premaxilla and dentary wide,
with strongly curved series of teeth that run parallel to each
other mesially and diverge laterally (Fig. 3). Teeth small and
robust; asymmetrically bifid, medial cusp broad. Lateral cusp
small and pointed, reaching approximately half length of
medial cusp. Accessory patch of unicuspid teeth on both
premaxilla and dentary bones absent.
Dorsal fin originating slightly anterior to vertical line
passing through pelvic-fin origin. Dorsal fin short, reaching
three plates behind its base when adpressed. Nuchal plate
exposed, not covered by skin. Dorsal-fin spinelet transverse-
ly oval-shaped, platelike, wider than base of dorsal spine.
Dorsal-fin locking mechanism non-functional. Dorsal spine
moderately flexible, followed by seven branched rays.
Adipose fin absent. One to four median azygous platelets
between contralateral plates of the dorsal lateral series
located at adipose-fin place. Pectoral fin moderate in size,
with curved and flattened spine and six branched rays, first
longest; subsequent branched rays decrease gradually in size.
Posterior margin of pectoral fin slightly round, overlapping
pelvic-fin origin when adpressed. Pectoral-fin axillary slit
absent. Pelvic fin with one unbranched and five branched
rays, reaching anal-fin origin when adpressed in males,
reaching to point midway between anus and anal-fin origin
in females. Pelvic-fin unbranched ray depressed, covered
with minute odontodes ventrally and laterally; odontodes
on ventral margin strongly turned mesially (Fig. 2). Well-
developed dermal flap along posterodorsal margin of
thickened first pelvic-fin unbranched ray, extending to ray
tip in mature males; absent in females. Pelvic-fin flap
slightly higher near fin base. Anal fin long with one
Fig. 2. Pelvic fin of Plesioptopoma curvidens, MCP 46268, 82.8 mm SL,
ventral view. Unbranched pelvic-fin ray with odontodes bent and turned
mesially. Scale 55 mm.
Fig. 3. Premaxillary tooth series of Plesioptopoma curvidens, MCP
36861. Scale 51 mm.
Fig. 4. Anterior head of Plesioptopoma curvidens, MCP 36861,
38.0 mm SL, lateral view. Scale 55 mm.
8Copeia 2012, No. 1
unbranched and five branched rays; distinctly larger in
males than in females. Caudal fin forked to slightly concave;
upper lobe slightly longer than lower; one upper un-
branched, 14 branched, and one lower unbranched rays.
Vertebral centra 31(3), pleural ribs present on centra 6–14(2)
or 6–15(1).
Color in alcohol.—Ground color of dorsal surface of head and
body light to dark brown. Cheeks, anterior margin of snout,
area between nostrils and orbits, and compound pterotic
covered with small, irregularly shaped, black or dark brown
dots. Dark dots on cheeks and compound pterotic usually
coalesced to form a darker area in juveniles. Flanks,
including mid-dorsal, median, and mid-ventral series of
lateral plates darkened, forming inconspicuous dark stripe
from head to caudal fin. One conspicuous dark brown
saddle immediately posterior to dorsal-fin base, coalesced
with lateral stripe. Second indistinct dark saddle at adipose-
fin location sometimes present. Light to dark brown
ventrally, darker on caudal peduncle. All fins with several
dark brown dots arranged in few irregular series.
Sexual dimorphism.—Adult males of Plesioptopoma curvidens
can be distinguished from females by the following sexually
dimorphic characters: genital papilla posterior to the anus
present (vs. absent in females); pelvic fin reaching anal-fin
origin when adpressed (vs. reaching to point midway
between anus and anal-fin origin in females); well-developed
dermal flap along posterodorsal margin of unbranched, first
pelvic-fin ray (vs. absent in females); and anal fin longer
(19.1–20.5%SL vs. 16.1%SL in females). Four adult males and
one adult female examined (Table 1).
Table 1. Morphometrics of Holotype and Paratypes of Plesioptopoma curvidens, for Large (n=5) and Small (n=10) Specimens. Values are given as
percents of standard length or head length. SD =standard deviation, H =holotype.
Specimens above 53 mm SL Specimens below 38 mm SL
H Min Max Mean SD Min Max Mean SD
Standard length (mm) 82.8 53.2 82.8 73.3 28.8 37.5 33.5
Percents of standard length
Head length 32.0 32.0 32.9 32.6 0.35 33.1 36.3 34.6 1.06
Predorsal length 41.4 41.4 42.9 42.4 0.60 41.6 44.7 42.7 0.86
Postdorsal length 46.9 45.4 47.5 46.5 0.77 43.7 46.9 45.4 1.07
Preanal length 57.9 57.9 61.4 59.2 1.37 58.1 60.5 59.2 0.77
Dorsal-fin spine length 25.0 22.9 25.0 24.3 0.98 23.1 25.8 24.4 0.84
Anal-fin spine length 20.2 16.1 20.6 19.2 1.81 16.9 19.1 18.4 0.75
Pectoral-fin spine length 19.8 18.1 20.4 19.3 0.98 16.6 19.1 17.6 0.91
Ventral-fin spine length 20.3 18.3 21.3 19.9 1.09 13.8 17.5 15.8 1.19
Upper caudal-fin ray 25.8 28.8 27.6 1.55 17.2 33.4 28.0 5.18
Lower caudal-fin ray 25.2 21.3 25.9 24.7 1.92 26.3 31.2 28.2 1.64
Trunk length 14.7 14.7 16.6 15.2 0.80 15.1 17.0 15.8 0.66
Abdominal length 20.9 20.9 23.1 22.0 0.99 19.8 22.2 21.1 0.74
Cleithral width 25.0 24.5 25.0 24.8 0.22 23.2 25.1 24.1 0.65
Body depth as dorsal-fin origin 17.9 16.4 20.6 18.7 1.64 15.1 17.7 16.7 0.88
Body width at dorsal-fin origin 19.7 17.9 23.5 20.2 2.14 14.8 21.1 17.9 1.56
Body width at anal-fin origin 13.4 12.5 15.1 13.9 1.02 10.3 12.9 11.8 0.90
Caudal peduncle length 42.9 39.8 42.9 41.3 1.17 39.5 42.6 41.0 0.94
Caudal peduncle depth 7.9 7.9 8.8 8.3 0.36 7.9 9.1 8.5 0.42
Caudal peduncle width 4.7 4.7 5.6 5.2 0.43 4.5 6.0 5.2 0.43
Percents of head length
Snout length 58.9 53.8 59.3 57.2 2.31 49.5 55.4 51.0 1.80
Orbital diameter 11.3 10.5 13.1 11.7 0.98 12.9 14.9 14.0 0.68
Interorbital width 35.5 32.4 36.0 34.5 1.58 34.7 39.7 36.5 1.49
Internarial width 12.8 10.3 12.8 11.9 1.13 11.9 16.7 13.8 1.81
Head depth 47.5 46.3 49.2 47.6 1.22 43.4 47.9 45.8 1.41
Mandibulary ramus 12.8 11.1 13.9 12.6 1.28 10.8 13.6 11.9 0.90
Counts
Premaxillary teeth right 21 18 23 20.2 2.17 16 20 18.4 1.26
Premaxillary teeth left 22 20 23 21.2 1.30 16 21 19.2 1.69
Dentary teeth right 20 15 20 17.8 2.17 11 20 15.0 2.51
Dentary teeth left 17 17 21 18.0 1.73 10 22 16.1 3.52
Plates in median lateral series 27 27 27 27.0 0.00 26 27 26.9 0.32
Plates as dorsal-fin base 5 5 6 5.2 0.45 5 5 5.0 0.00
Plates at anal-fin base 4 3 4 3.4 0.55 3 3 3.0 0.00
Plates between anal and caudal 12 11 12 11.8 0.45 12 13 12.2 0.42
Reis et al.—New loricariid genus 9
Distribution and habitat.—Plesioptopoma curvidens is only
known from the type locality, the upper portion of the Rio
Paraopeba, a tributary to the upper Rio Sa˜o Francisco near
Cristiano Otoni, Minas Gerais, Brazil (Fig. 5). The Rio
Paraopeba at the type locality is a small stream of about 2–
4 meters wide and up to 0.5 meters deep. The water was clear
but heavily polluted by organic sewage, had fair amounts of
marginal, submerged, and emergent vegetation, and the
bottom was mostly sandy with patches of gravel and pebbles.
Etymology.—The specific epithet curvidens is from the Latin
curvus, meaning curved, bent, and dens, meaning tooth, in
allusion to the strongly curved tooth series in both the
premaxilla and dentary. A noun in apposition.
DISCUSSION
Plesioptopoma is a phenotypically remarkable taxon in that it
shows external similarity to some hypostomines or neople-
costomines. Despite the external similarity to other subfam-
ilies and its larger size compared to most other hypoptopo-
matines, Plesioptopoma is unambiguously assigned to that
subfamily based on the possession of five derived features.
The Hypoptopomatinae were most recently diagnosed in
Schaefer (1998), based on six derived characters. Plesiopto-
poma shares three of those six characters: (1) Open nasal
capsule (character 5); is found in most Hypoptopomatines,
where the lateral ethmoid does not form a complete capsule
around the nasal organ. In Plesioptopoma the lateral ethmoid
is well developed but the nasal capsule is open laterally. (2)
Enlarged fenestrae on the compound pterotic (character 10);
present in Plesioptopoma (Fig. 4). (3) Metapterygoid channel
present (character 13); a condition shared by Plesioptopoma.
This condition, however, is widespread among neoplecos-
tomines and other subfamilies, and is likely a plesiomorphy
among the hypoptopomatines.
In the remaining three characters reported by Schaefer
(1998), Plesioptopoma exhibits the plesiomorphic state: (4)
Pectoral skeleton arrector fossa either partially or completely
closed by a ventral lamina of the coracoids (character 30);
arrector fossa in Plesioptopoma is completely open. (5)
Presence of a median rostral plate on the snout (character
34); is not shared by Plesioptopoma, which is devoid of
dermal plates on the anterior snout border. (6) Enlarged
snout odontodes (character 39); also absent in the new
genus because of the absence of dermal plates on anterior
snout.
One additional character not included by Schaefer (1998)
that diagnoses the hypoptopomatines was also found in
Plesioptopoma. Contrary to all other loricariids, the hypop-
topomatines possess the pectoral girdle exposed ventrally,
either totally or in part. The ventral surface of the coracoid
of Plesioptopoma shows a small area exposed and supporting
a few odontodes laterally, close to the pectoral-fin insertion
(Fig. 1), most of the pectoral girdle being covered by skin
and dermal plates medially.
A second, previously unrecognized, derived feature of
the hypoptopomatines, although also shared with the
neoplecostomine Kronichthys,istheodontodesonthe
ventral surface of the pelvic-fin unbranched ray distinctly
bent and turned mesially (Fig. 2). These mesially turned
odontodes help the fish grasp marginal leaves and plant
stalks with the pelvic fins and hold position in the water
current. Even those hypoptopomatines that are most
commonly found among stones (Eurycheilichthys,Epactiono-
tus, some Parotocinclus species) share this feature, as most of
them usually hang from marginal vegetation when young.
Thus, although Plesioptopoma shares an overall similarity
with some loricariids other than hypoptopomatines, and
especially Kronichthys, the presence of some, but not all,
diagnostic hypotopomatine characters suggests that the
species belongs with that subfamily, albeit at or near the
basal node of the group and not with any of the included
genera.
Among the neoplecostomines, Plesioptopoma is most
similar to Kronichthys, with whom it shares the narrow and
elongate body shape and the tooth series in both the
premaxilla and dentary strongly curved medially (Fig. 3).
However, Kronichthys does not exhibit the hypoptopomatine
characters listed above, and thus the shared characters are
best interpreted as homoplasies at this time. Conversely,
Plesioptopoma is distinguished from Kronichthys by not having
plates on the anterior snout border (vs. plates present); by
having the anterior border of the mesethmoid arrow-shaped
(vs. straight); by having two foramina on the hyomandibula
(vs. hyomandibular foramina absent); by not having an
accessory flange on the first epibranchial (vs. accessory flange
present); and by having a dorsal process on the anterior shelf
of the basipterygium (Fig. 6; vs. dorsal process absent).
Among the Hypoptopomatinae, Plesioptopoma is easily
diagnosed by possessing three distinguishing features: the
functional tooth series in both the premaxilla and dentary
are strongly curved medially, with the series running
parallel to each other medially (Fig. 3). This character is
shared by the species of the neoplecostomine Kronichthys
and, to a lesser extent, by the hypoptopomatine Parotocin-
clus prata. The new genus is further distinguished from
Parotocinclus prata, however, by lacking a rostral plate (vs.
rostral plate present), by having two postrostral plates
(Fig. 4; vs. four postrostral plates), and by the straight
anterior margin of the mesethmoid (vs. mesethmoid
pointed anteriorly). Plesioptopoma is also distinguished from
the remaining hypoptopomatines, except Pseudotocinclus,by
Fig. 5. Type locality of Plesioptopoma curvidens in the upper Rio
Paraopeba, Rio Sa˜ o Francisco basin, central Brazil.
10 Copeia 2012, No. 1
having the caudal peduncle distinctly quadrangular in cross-
section (vs. caudal peduncle ovoid in cross-section). It is
easily distinguished from Pseudotocinclus,however,by
having the first anal-fin pterygiophore covered by skin (vs.
exposed ventrally in front of the anal-fin unbranched ray)
and the ventral surface of pectoral girdle hardly exposed
laterally (vs. ventral surface of pectoral girdle widely exposed
laterally). Finally, the new genus is diagnosed among the
hypoptopomatines, except Gymnotocinclus, by having the
anterior margin of the snout devoid of dermal plates (Fig. 4;
vs. anterior margin of snout plated). It can be distinguished
from Gymnotocinclus, however, by having a connecting bone
and complete body plating (vs. connecting bone absent and
body plating extremely reduced).
The features Plesioptopoma shares with Gymnotocinclus and
Parotocinclus prata, basal members of the Hypoptopomatinae,
and the currently neoplecostomine Kronichthys,issuggestive
of its relatively basal position among the hypoptopomatines.
To uncover the phylogenetic relationships of Plesioptopoma is
beyond the objectives of the present paper. That, however, is
currently being investigated by the authors and thus deferred
to another paper.
MATERIAL EXAMINED
Parotocinclus prata: MCP 28322, 18, 1 CS, Minas Gerais,
Presidente Olega´rio, Rio Sa˜o Francisco basin, Co´rrego
Altinas, ca. 10 km from Presidente Olega´ rio toward Galena;
MCP 27381, 4 paratypes, Minas Gerais, Presidente Olega´ rio,
Rio Sa˜o Francisco basin, Rio da Prata, creek tributary to
Ribeira˜o Quirico´.
Pseudotocinclus juquiae: MCP 45129, 2 +2 CS, Sa˜o Paulo,
Juquitiba, creek at Fazenda Estio on road from Santa Rita to
Juquitiba.
Pseudotocinclus parahybae: MCP 45094, 4, Sa˜o Paulo, Pinda-
monhangaba, Rio Paraı´ba do Sul basin at Bairro Ribeira˜o
Grande, Co´ rrego do Convento; MZUSP 47581, 1 CS
paratype, Sa˜o Paulo, Pindamonhangaba, Rio Paraı´ba do Sul
basin, creek tributary to Ribeira˜o Grande at Fazenda Sa˜o
Sebastia˜o do Ribeira˜o Grande.
ACKNOWLEDGMENTS
We are grateful to P. Buckup (MNRJ) for the loan of
specimens and for calling our attention to this material.
Thanks are due to the All Catfish Species Inventory (NSF-
DEB #0315963), which financed the MCP expedition
during which part of the type material was collected. EHLP
is partially financed by a Post-Doc fellowship from CNPq
(process #151624/2009-7), PLA is partially financed by
CNPq (process #151213/2009-7), and RER is partially
financed by CNPq (process #303362/2007-3).
LITERATURE CITED
Lehmann, A. P. 2006. Anatomia e relac¸o˜es filogene´ ticas da
famı´lia Loricariidae (Ostariophysi: Siluriformes) com eˆn-
fase na subfamı´lia Hypoptopomatinae. Unpubl. Ph.D.
diss., Pontifı´cia Universidade Cato´ lica do Rio Grande do
Sul, Porto Alegre, Brazil.
Pereira, E. H. L. 2009. Relac¸o˜ es filogene´ticas de Neoplecos-
tominae Regan, 1904 (Siluriformes: Loricariidae). Unpubl.
Ph.D. diss., Pontifı´cia Universidade Cato´ lica do Rio
Grande do Sul, Porto Alegre, Brazil.
Pereira, E. H. L., F. Vieira, and R. E. Reis. 2007. A new
species of sexually dimorphic Pareiorhaphis Miranda
Ribeiro, 1918 (Siluriformes: Loricariidae) from the Rio
Doce basin, Brazil. Neotropical Ichthyology 5:443–448.
Schaefer, S. A. 1997. The neotropical cascudinhos: system-
atics and biogeography of the Otocinclus catfishes (Silur-
iformes: Loricariidae). Proceedings of the Academy of
Natural Sciences of Philadelphia 148:1–120.
Schaefer, S. A. 1998. Conflict and resolution: impact of new
taxa on phylogenetic studies of the neotropical cascudin-
hos (Siluroidei: Loricariidae), p. 375–400. In: Phylogeny
and Classification of Neotropical Fishes. L. R. Malabarba,
R. E. Reis, R. P. Vari, Z. M. S. Lucena, and C. A. S. Lucena
(eds.). Edipucrs, Porto Alegre, Brazil.
Taylor, W. R., and G. C. Van Dyke. 1985. Revised
procedures for staining and clearing small fishes and
other vertebrates for bone and cartilage study. Cybium
9:107–119.
Fig. 6. Pelvic girdle of Plesioptopoma curvidens, MNRJ 21426, dorsal
view. B, basipterygium; DP, dorsal process. Scale 52 mm.
Reis et al.—New loricariid genus 11
... In the last 10 years, about 51 species of Otothyrini and 16 species of Hypoptopomatini have been described , as well as five new genera. Carvalho et al. (2008) described Gymnotocinclus a monotypic genus from the rio Tocantins basin; Martins & Langeani (2011) described Rhinolekos to accommodate three new species from the rio Paranaíba basin; Reis et al. (2012) described the monotypic genus Plesioptopoma from the upper rio São Francisco basin as a possible member of the Otothyrini, despite the fact that it shares several characters with members of Neoplecostomini; and Roxo et al. (2015a) described Curculionichthys to reallocate several species previously assigned to Hisonotus that were not closely related to the type species, H. notatus Eigenmann & Eigenmann, 1889. ...
... In our study, Nannoplecostomus eleonorae appeared as a sister group to all remaining species of Neoplecostomini. Reis et al. (2012) said that Plesioptopoma curvidens presented several synapomorphic characters with species of Otothyrini and Neoplecostomini. However, the authors preferred to include this taxon in Otothyrini based on the presence of: ...
... (1) open nasal capsule; (2) enlarged fenestrae on the compound pterotic; (3) metapterygoid channel present; (4) arrector fossae completely opened (a plesiomorphic state of ; (5) ventral surface of the coracoid partially exposed. Furthermore, Reis et al. (2012) recognized another character shared among species of Hypoptopomatini and Otothyrini (referred in that work as non-Hypoptopomatinae loricariids) where the odontodes on the ventral surface of the pelvic-fin unbranched ray are distinctly bent and turned mesially. The authors also suggested that P. curvidens has similarities to Parotocinclus prata Ribeiro, Melo & Pereira, 2002, Gymnotocinclus and Pseudotocinclus (Otothyrini); however, our phylogenetic analysis does not corroborate this hypothesis as Plesioptopoma curvidens is the sister to all species of Neoplecostomus Eigenmann & Eigenmann, 1888, except N. ribeirensis Langeani, 1990 plus all species of Pareiorhina, except P. rudolphi (Miranda Ribeiro, 1911). ...
Article
Full-text available
Gymnotocinclus canoeiro n. sp. of the Hypoptopomatinae is described from small tributaries of the upper rio Tocantins basin. It is distinguished from G. anosteos by having five characters: (1) the presence of body dermal plates, (2) the pectoral girdle not exposed in ventral view, (3) the pelvic spine longer than pectoral spine in males, (4) the pectoral fin with seven to eight branched rays, and (5) the presence of an adipose fin. Furthermore, maximum likelihood (ML) analysis was used to estimate a molecular phylogeny from previously published data of one nuclear (F-Reticulon 4) and three mitochondrial (16S RNA, COI and CytB) genes. The phylogenetic results revealed the new species as a sister taxon of Gymnotocinclus anosteos within the Otothyrini. We also included samples of Nannoplecostomus eleonorae that appeared sister group to all other Neoplecostomini species, and Plesioptopoma curvidens that appeared within the Neoplecostomini forming a sister clade to all species of Neoplecostomus, except N. ribeirensis and the species of Pareiorhina, except P. rudolphi.
... Our results conflicted with the morphology-based results of Reis et al. (2012) and Pereira and Reis (2017) by finding the monotypic genus Plesioptopoma sister to 'Pareiorhina' carrancas (ML and BI), forming a clade nested within Neoplecostomini. Reis et al. (2012) noted similarities between Plesioptopoma and the neoplecostomine genus Kronichthys (e.g., narrow elongate body, premaxillary and dentary tooth series strongly curved medially), yet Pereira and Reis (2017) excluded Plesioptopoma from subfamily Neoplecostominae because it lacks one exclusive synapomorphy: anteriormost pleural ribs connected to vertebral centra via ligament (vs. ...
... Our results conflicted with the morphology-based results of Reis et al. (2012) and Pereira and Reis (2017) by finding the monotypic genus Plesioptopoma sister to 'Pareiorhina' carrancas (ML and BI), forming a clade nested within Neoplecostomini. Reis et al. (2012) noted similarities between Plesioptopoma and the neoplecostomine genus Kronichthys (e.g., narrow elongate body, premaxillary and dentary tooth series strongly curved medially), yet Pereira and Reis (2017) excluded Plesioptopoma from subfamily Neoplecostominae because it lacks one exclusive synapomorphy: anteriormost pleural ribs connected to vertebral centra via ligament (vs. posterior ribs articulated directly). ...
Article
Neotropical freshwaters host more than 6000 fish species, of which 983 are suckermouth armored catfishes of the family Loricariidae – the most-diverse catfish family and fifth most species-rich vertebrate family on Earth. Given their diversity and ubiquitous distribution across many habitat types, loricariids are an excellent system in which to investigate factors that create and maintain Neotropical fish diversity, yet robust phylogenies needed to support such ecological and evolutionary studies are lacking. We sought to buttress the systematic understanding of loricariid catfishes by generating a genome-scale data set (1041 loci, 328,330 bp) for 140 species spanning 75 genera and five of six previously proposed subfamilies. Both maximum likelihood and Bayesian analyses strongly supported the monophyly of Loricariidae. Our results also reinforced the established backbone of loricariid interrelationships: Delturinae as sister to all other analyzed loricariids, with subfamily Rhinelepinae diverging next, followed by Loricariinae sister to Hypostominae + Hypoptopomatinae. Previous DNA-based relationships within Hypostominae and Loricariinae were strongly supported. However, we evaluated for the first time DNA-based relationships among many Hypoptopomatinae genera and found significant differences with this subfamily's current genus-level classification, prompting several taxonomic changes. Finally, we placed our topological results within a fossil-calibrated temporal context indicating that early Loricariidae diversification occurred across the Cretaceous-Paleogene boundary ∼65 million years ago (Ma). Our study lays a strong foundation for future research to focus on relationships among species and the macroevolutionary processes affecting loricariid diversification rates and patterns.
... Interestingly, H. alberti and H. vespuccii appear to have broad distributions whereas H. bocaiuva and H. devidei appear to be more restricted within small drainages where they occur (Fig. 5). Although some endemic species of Hypoptopomatinae have been recently described from the Rio São Francisco, including the monotypic Plesioptopoma curvidens Reis et al., 2012, the total number of hypoptopomatine species from that basin is smaller (nine species) than in either the Amazon (40 species) or the La Plata basins (42 species) and the total number of species in Atlantic coastal rivers from the Orinoco Basin to Argentina (63 species). Even with the Rio São Francisco being the twenty-third largest river in the world and the third largest in South America (Potter, 1997) and the fact that the basin has high rates (Abell et al., 2008), we expect that more undescribed species of Hypoptopomatinae will become known as collection efforts increase in the future. ...
Article
Full-text available
A recent expedition to headwaters of the Rio Pandeiros, a left‐bank tributary of the Rio São Francisco revealed the presence of a fourth species of Hisonotus from that basin. Hisonotus devidei sp. nov. differs from congeners by the presence of conspicuous dark blotches of distinct shapes irregularly arranged along lateral and dorsal surfaces of the body and scattered throughout all fins, by possessing small plates in lateral portions of the abdomen and adjacent areas between pelvic fins without development of dermal plates and by morphometric ratios. The putative phylogenetic placement of the new species is discussed based on morphological comparisons with species of related Hypoptopomatinae genera and the Hisonotus species diversity within the Rio São Francisco Basin is compared with that of adjacent basins.
... However, the lack of taxonomic definition of the species of Hypostomus from the rio São Francisco basin hampers deeper phylogenetic and biogeographic investigations. Although none species of Hypostomus were recently described, several species from different subfamilies within Loricariidae were recently discovered and described, such as the Hypoptopomatini Reis et al. 2012;Roxo et al. 2013), Loricariinae (Oyakawa 1993;Langeani et al. 2001), and Neoplecostomini (Oliveira & Oyakawa 1999;Roxo et al. 2012a). The objective of the present work is to describe a new species of Hypostomus with dark spots and keels from the rio São Francisco basin. ...
Article
Full-text available
Hypostomus velhochico sp. n., is described from the rio São Francisco basin, in the states of Minas Gerais and Bahia, Brazil. The new species is mainly distinguished from its congeners by a combination of characters such as slender bicuspid teeth, dentaries angled more than 90 degrees, conspicuous keels along lateral series of plates, small roundish dark spots, one plate bordering supraoccipital, spots aligned along lateral series of plates, and by attaining small to medium size. Hypostomus velhochico is widespread in the rio São Francisco basin and has a more similar general pattern of external morphology to species from the Northeastern Brazilian Coastal drainages than to species of the rio São Francisco basin. Aspects about its ecology and its putative relationship are discussed.
... Although the Rio São Francisco basin represents the third largest drainage in Brazil (Kohler, 2003), it is inhabited by relatively few Hypoptopomatinae species compared to other drainages located in the Brazilian crystalline shield, where the subfamily has its highest richness. In fact, currently only nine hypoptopomatines species are known for the basin: Otocinclus xakriaba Schaefer, 1997, Parotocinclus jumbo Britski & Garavello, 2002, P. prata Ribeiro, Melo & Pereira, 2002, Plesioptopoma curvidens Reis, Pereira & Lehmann, 2012, Parotocinclus robustus Lehmann & Reis, 2012, Hisonotus bocaiuva Roxo, Silva, Oliveira & Zawadzki, 2013, Microlepidogaster discontenta, H. vespuccii Roxo, Silva & Oliveira, 2015, and H. alberti Roxo, Silva, Waltz & Melo, 2016. In this respect, Langeani et al. (2009) have already suggested prudence to considering the ichthyofauna of the Rio São Francisco basin as well-known, based primarily on the low frequency of new species descriptions in the beginning of twenty-first century. ...
Article
Full-text available
The number of species of Microlepidogaster recently increased considerably, the genus presently comprises six species distributed in the Paraná, São Francisco, and Jequitinhonha river basins. A new species of Microlepidogaster is herein described from the upper Rio São Francisco basin, which can be distinguished from all congeners by having two exclusive features within the genus: skin over swimbladder opening with two to five reduced unperforated platelets, and ventral laminar expansion of coracoid enclosing completely or almost completely the arrector fossa of the pectoral girdle. In addition, other features to recognize this species are: snout covered by many small plates bearing slender pointed odontodes; presence of iris operculum; exposure of pectoral girdle restricted to the lateral portion; presence of pectoral axillary slit only in juveniles; anterior portion of compound supraneural plus first dorsal-fin proximal radial contacting the neural spine of the eighth or ninth vertebra; first anal-fin pterygiophore covered only by skin; and uninterrupted, long median and mid-dorsal series of lateral plates.
... Hypoptopomatinae is a monophyletic subfamily comprised of 20 genera (Reis et al., 2012). Most species are relatively small as adults, ranging from 20 to 45 mm in SL. ...
Article
Full-text available
Uma filogenia das espécies do gênero de Loricariidae Acestridium e grupos externos relevantes é apresentada com base na análise de parcimônia de 52 caracteres morfológicos não pesados e desordenados. Acestridium é diagnosticado como monofilético com base na posse de 17 sinapomorfias exclusivas. Duas árvores primárias foram encontradas e o consenso estrito entre essas árvores alternativas resultou nas seguintes relações: ((A. dichromum + A. triplax)(A. gymnogaster + A. scutatum + (A. discus (A. colombiensis + A. martini)))). Acestridium foi encontrado como grupo-irmão de Niobichthys e este clado como grupo-irmão sucessivo de Oxyropsis + Hypoptopoma.
... longicolla Calegari et al., 2010 andM. arachas Martins et al., 2013), Plesio ptopoma Reis et al., 2012, Pseudotocinclus Nichols, 1919, and Rhinolekos Martins & Langeani, 2011b. Among these plesiomorphic features we have: 1) snout with many small plates, leaving a small naked area in its most anterior portion, instead of a completely plated snout, with a single or paired rostral plate characteristic to many derived Hypoptopomatinae taxa; 2) abdomen with numerous small plates randomly arranged, differing from many derived taxa that have large plates, usually disposed in aligned rows; 3) small odontodes on the anterior portion of snout, very similar to those of the remaining head, instead of well-developed odontodes in dorsal and/or ventral portions of snout as in derived Hypoptopomatinae; and 4) absence of pectoral axillary slit in adults (no specimen of C. saxatilis smaller than 24.4 mm SL could be examined), differing from most of derived hypoptopomatines which maintain a pectoral slit even in adults. ...
Article
Chauliocheilos saxatilis, new genus and species, is described from headwater streams of the rio Itamarandiba, upper rio Jequitinhonha basin, southeastern Brazil. The new genus is diagnosed from all other Loricariidae members by having a unique labial appendix at laterodorsal portion of lower lip, associated to the proximal region of insertion of the maxillary barbel. From all Hypoptopomatinae genera, Chauliocheilos can be distinguished by having two additional series of lateral plates, one between the dorsal and mid-dorsal series, and the other between the mid-ventral and ventral series. In addition, the great number of lateral plates, the absence of the iris operculum, and the posterior dorsal-fin insertion contacting the neural spine of eighth vertebra, are other useful features to recognize the genus. The phylogenetic position of Chauliocheilos among the Hypoptopomatinae, as well as the morphology and possible functions of the labial appendix, are discussed.
... The genus Parotocinclus Eigenmann & Eigenmann comprises 26 valid nominal species of small hypoptopomatine catfishes, known in Brazil as "cascudinhos", widely distributed in the Neotropical Cis-Andean region, extending from Venezuela to southern Brazil (Sarmento-Soares et al., 2009;Lehmann et al., 2013). The Hypoptopomatinae is a monophyletic subfamily within the Loricariidae that currently includes 20 genera (Carvalho et al., 2008;Reis et al., 2012), in spite of the controversial monophyletic condition of the genus Parotocinclus (Schaefer, 1998;Ribeiro et al., 2002;Gauger & Buckup, 2005;Sarmento-Soares et al., 2009). ...
Article
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A new species of Parotocinclus is described from the upper rio Piranhas-Açu basin, northeastern Brazil. The new species differs from all its congeners, except P. bidentatus, P. muriaensis (both from rio Paraíba do Sul basin, southeastern Brazil), and P. spilurus (rio Jaguaribe basin, northeastern Brazil) by presenting the adipose fin rudimentary or absent. The new species differs from P. bidentatus, P. muriaensis, and P. spilurus mainly by presenting the abdomen region extensively naked, with few reduced rounded dermal platelets between the pectoral girdle and the anus. Parotocinclus seridoensis is probably an endemic species of the semi-arid Caatinga, region where the genus presents high species richness.
Article
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The Neotropical catfish genus Kronichthys contains three species distributed along coastal rivers of southern and southeastern Brazil. Although phylogenetic hypotheses are available, the molecular and morphological diversity and species boundaries within the genus remain unexplored. Here, we generated mitochondrial data for 90 specimens combined with morphometric and meristic data to investigate species diversity, species boundaries, and putative morphological signatures in Kronichthys. Phylogenetic and species delimitation results clearly show the presence of four genetic lineages, three within K. heylandi along the coast from Rio de Janeiro to southern São Paulo and a single lineage encompassing both the nominal species K. lacerta and K. subteres from the Ribeira de Iguape basin to Santa Catarina in southern Brazil. Morphological data, however, show overlapped ranges in morphometrics and a definition of only two morphotypes, with clear phenotypic differences in the teeth number: K. heylandi differs from K. subteres+K. lacerta by the higher number of premaxillary teeth (30–52 vs. 19–28) and higher number of dentary teeth (28–54 vs. 17–28). Headwater captures and connections of paleodrainages due to sea‐level fluctuations represent the two major biogeographic processes promoting species diversification and lineage dispersal of Kronichthys in the Atlantic coastal range of Brazil. This article is protected by copyright. All rights reserved.
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This study presents the description of a new genus of the catfish subfamily Neoplecostominae from the Tocantins River basin. It can be distinguished from other neoplecostomine genera by the presence of (1) three hypertrophied bicuspid odontodes on the lateral portion of the body (character apparently present in mature males); (2) a large area without odontodes around the snout; (3) a post-dorsal ridge on the cau-dal peduncle; (4) a straight tooth series in the dentary and premaxillary rows; (5) the absence of abdominal plates; (6) a conspicuous series of enlarged papillae just posterior to the dentary teeth; and (7) caudal pe-duncle ellipsoid in cross section. We used maximum likelihood and Bayesian methods to estimate a time-calibrated tree with the published data on 116 loricariid species using one nuclear and three mitochondrial genes, and we used parametric biogeographic analyses (DEC and DECj models) to estimate ancestral geographic ranges and to infer the colonization routes of the new genus and the other neoplecostomines in the Tocantins River and the hydrographic systems of southeastern Brazil. Our phylogenetic results indicate that the new genus and species is a sister taxon of all the other members of the Neoplecostominae, originating during the Eocene at 47.5 Mya (32.7–64.5 Mya 95% HPD). The present distribution of the new genus and other neoplecostomines may be the result of a historical connection between the drainage basins of the Paraguay and Paraná rivers and the Amazon basin, mainly through headwater captures.
Article
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Pareiorhaphis nasuta, a new neoplecostomine catfish of the family Loricariidae is described. The species was collected from headwaters of the rio Matipó, tributary of the upper rio Doce basin in State of Minas Gerais, Brazil. The new species is readily diagnosed from all remaining congeners by the longer snout and by the smaller orbital diameter. The new species is the first representative of the genus Pareiorhaphis discovered in the rio Doce basin, thus expanding its geographic distribution. A phylogenetic diagnosis for Pareiorhaphis is presented. Pareiorhaphis nasuta, um novo cascudo neoplecostomíneo da família Loricariidae é descrito. Os exemplares foram capturados nas cabeceiras do rio Matipó, tributário do rio Doce no Estado de Minas Gerais, Brasil. A nova espécie é facilmente diagnosticada entre todos os demais congêneres pelo maior comprimento do focinho e pelo menor diâmetro orbital. Esta nova espécie representa o primeiro registro do gênero Pareiorhaphis na bacia do rio Doce, expandindo a sua distribuição geográfica. Uma diagnose filogenética é apresentada para Pareiorhaphis.
Article
The genus Otocinclus Cope (1872) of the siluriform family Loricariidae is diagnosed as monophyletic on the basis of shared derived characters of the cranial and hyobranchial skeleton, dorsal gill arch musculature, and gut. Otocinclus are relatively small herbivorous catfishes restricted to small streams and quiet slow-flowing margins of larger rivers, most frequently living in close association with aquatic macrophytes and terrestrial marginal grasses extending into the water column. Otocinclus species share a novel modification of the distal esophageal wall which is developed into an accessory blind diverticulum that may function in aerial respiration and for providing additional modulatory positive buoyancy for remaining in the upper water column at stream margins. Otocinclus has no junior synonyms, however several nominal species originally described in Otocinclus are here formally re-assigned to other genera in the subfamily Hypoptopomatinae. Otocinclus cephalacanthus Ribeiro 1911, O. depressicauda Ribeiro 1918, O. francirochai Ihering 1928, O. laevior Cope 1894, O. leptochilus Cope 1894, O. maculipinnis Regan 1904, O. nigricauda Boulenger 1891, and O. paulinus Regan 1908 are all placed in the genus Microlepidogaster Eigenmann & Eigenmann 1889; O. obtusos Ribeiro 1911 was placed in Pseudotothyris Britski & Garavello 1984; the genus Nannoptopoma Schaefer 1996 was erected for O. spectabilis Eigenmann 1914 in the tribe Hypoptopomatini; O. gibbosus Ribeiro 1908 is removed from Otocinclus, yet remains of undetermined generic status. Thirteen species are recognized in Otocinclus: O. affinis Steindachner 1877 of the lower Paraná/Paraguay and Uruguay basins and coastal streams of southeastern Brazil; O. bororo n. sp. of the upper Río Paraguay; O. caxarari n. sp. of the middle Río Guaporé/Mamoré system; O. flexilis Cope 1894 of the lower Paraná/Paraguay and Uruguay basins and coastal streams of southeastern Brazil; O. hasemani Steindachner 1915 of northern Brazil; O. hoppei Ribeiro 1939 of the upper Amazon, Tocantins and Paraguay basins and coastal streams of northeastern Brazil; O. huaorani n. sp. of the upper Amazon and Orinoco basins; O. macrospilus Eigenmann & Allen 1942 of the upper Amazon basin of Colombia, Ecuador, and Peru; O. mariae Fowler 1940 of the lower Amazon, upper Madeira and Paraguay basins; O. mura n. sp. of the middle Amazon River; O. vestitus Cope 1872 of the upper Amazon and lower Paraná basins; O. vittatus Regan 1904 of the Amazon, Orinoco, Paraná/Paraguay, and Tocantins basins; and O. xakriaba n. sp. of the rio São Fransisco basin. Two species are placed in synonymy: Otocinclus arnoldi Regan 1909 and O. fimbriatus Cope 1894 are junior synonyms of O. flexilis. Keys to the species of Otocinclus and genera of the Hypoptopomatinae are provided. A descriptive treatment of the osteology and cranial myology is provided for O. vittatus. Detailed analysis of meristic and morphometric variation based on geometric morphometric procedures is provided for the phenetically similar species pairs O. mariae and O. vittatus, O. bororo and O. huaorani in an a posteriori evaluation of separate species status. The phylogenetic relationships among Otocinclus species, and the phylogenetic position of Otocinclus among genera of the Hypoptopomatinae, are determined based on analysis of 27 morphological features using cladistic parsimony. Monophyly of Otocinclus was confirmed; within Otocinclus, a clade comprised of O. affinis and O. flexilis is the sister-group to the remainder of the genus. Within that latter clade, O. hasemani and O. xakriaba are the first and second-level sister-groups to the remainder of the genus, within which relationships among species are not fully resolved with available data. The phylogenetic biogeography of Otocinclus is informative regarding the historical relationships among major river drainage basins, particularly of those river systems of the Brazilian Shield. A biogeographic hypothesis is proposed based on the area cladogram derived from the species-level phylogenetic relationships, which suggests successive vicariance and speciation in the non-Amazonian regions of endemism of southeastern and eastern South America, followed by speciation and dispersal within the Amazon, Orinoco and upper Paraguay basins. The pattern of vicariance revealed by the Otocinclus species-level phylogeny is congruent with the geologic history of the major river drainage basins of the Brazilian Shield. This result suggests that, for Otocinclus and perhaps other loricariid catfishes, much of their generic and species-level diversification occurred prior to the formation of the Amazon basin.
Revised procedures for staining and clearing small fishes and other vertebrates for bone and cartilage study Fig. 6. view. B, basipterygium; DP, dorsal process. Scale 5 2 mm. Pelvic girdle of Plesioptopoma curvidens, MNRJ 21426
  • W R Taylor
  • G C Van
  • Dyke
Taylor, W. R., and G. C. Van Dyke. 1985. Revised procedures for staining and clearing small fishes and other vertebrates for bone and cartilage study. Cybium 9:107–119. Fig. 6. view. B, basipterygium; DP, dorsal process. Scale 5 2 mm. Pelvic girdle of Plesioptopoma curvidens, MNRJ 21426, dorsal Reis et al.—New loricariid genus 11
Anatomia e relac ¸o ˜es filogene ´ticas da famı ´lia Loricariidae (Ostariophysi: Siluriformes) com e ˆn-fase na subfamı ´lia Hypoptopomatinae
  • A P Lehmann
Lehmann, A. P. 2006. Anatomia e relac ¸o ˜es filogene ´ticas da famı ´lia Loricariidae (Ostariophysi: Siluriformes) com e ˆn-fase na subfamı ´lia Hypoptopomatinae. Unpubl. Ph.D. diss., Pontifı ´cia Universidade Cato ´lica do Rio Grande do Sul, Porto Alegre, Brazil
Conflict and resolution: impact of new taxa on phylogenetic studies of the neotropical cascudin-hos (Siluroidei: Loricariidae), p
  • S A Schaefer
Schaefer, S. A. 1998. Conflict and resolution: impact of new taxa on phylogenetic studies of the neotropical cascudin-hos (Siluroidei: Loricariidae), p. 375–400.
Pelvic girdle of Plesioptopoma curvidens, MNRJ 21426, dorsal view. B, basipterygium; DP, dorsal process
  • Fig
Fig. 6. Pelvic girdle of Plesioptopoma curvidens, MNRJ 21426, dorsal view. B, basipterygium; DP, dorsal process. Scale 5 2 mm. Reis et al.—New loricariid genus
Relaçõ filogené de Neoplecos-tominae ReganSiluriformes: Loricariidae). Unpubl. Ph.D. diss., Pontifí Universidade Cató lica do Rio Grande do Sul A new species of sexually dimorphic Pareiorhaphis Miranda Ribeiro
  • Porto Sul
  • Alegre
  • Brazil
  • E H L Pereira
  • Brazil
  • E H L Pereira
  • F Vieira
Sul, Porto Alegre, Brazil. Pereira, E. H. L. 2009. Relaçõ filogené de Neoplecos-tominae Regan, 1904 (Siluriformes: Loricariidae). Unpubl. Ph.D. diss., Pontifí Universidade Cató lica do Rio Grande do Sul, Porto Alegre, Brazil. Pereira, E. H. L., F. Vieira, and R. E. Reis. 2007. A new species of sexually dimorphic Pareiorhaphis Miranda Ribeiro, 1918 (Siluriformes: Loricariidae) from the Rio Doce basin, Brazil. Neotropical Ichthyology 5:443–448.
Relações filogenéticas de Neoplecostominae ReganSiluriformes: Loricariidae)
  • E H L Pereira
Pereira, E. H. L. 2009. Relações filogenéticas de Neoplecostominae Regan, 1904 (Siluriformes: Loricariidae). Unpubl. Ph.D. diss., Pontifícia Universidade Cató lica do Rio Grande do Sul, Porto Alegre, Brazil.
A new species of sexually dimorphic Pareiorhaphis Miranda Ribeiro
  • E H L Pereira
  • F Vieira
  • R E Reis
Pereira, E. H. L., F. Vieira, and R. E. Reis. 2007. A new species of sexually dimorphic Pareiorhaphis Miranda Ribeiro, 1918 (Siluriformes: Loricariidae) from the Rio Doce basin, Brazil. Neotropical Ichthyology 5:443–448.