Description of a New Small Species of the Genus Cyphocharax (Characiformes: Curimatidae) from the Lower Amazon Basin

Abstract

Cyphocharax aninha, new species, is described from the Rio Mopeco, a left tributary of the Rio Paru, left of the lower Rio Amazonas. Cyphocharax aninha differs from its congeners by having the infraorbital sensory canal absent or greatly reduced, even in large individuals (more than 35.2 mm SL), and fleshy or osseous canal restricted to infraorbital 5; the presence of a broad ellipsoid, vertical elongate spot over the caudal peduncle and the base of the caudal-fin rays, between the dorsal and ventral margins of the caudal peduncle. The new species can also be distinguished from all congeners by the combination of morphometric, meristic and pigmentation characters. Comments on other small species and possible relationships of the new species with its congeners are presented.

Full text

Description of a New Small Species of the Genus Cyphocharax
(Characiformes: Curimatidae) from the Lower Amazon Basin
Wolmar Benjamin Wosiacki
1
and Dylria Paula da Silva Miranda
1
Cyphocharax aninha, new species, is described from the Rio Mopeco, a left tributary of the Rio Paru, left of the lower Rio
Amazonas. Cyphocharax aninha differs from its congeners by having the infraorbital sensory canal absent or greatly
reduced, even in large individuals (more than 30.0 mm SL), and fleshy or osseous canal restricted to infraorbital 5; the
presence of a broad ellipsoid, vertical elongate spot over the caudal peduncle and the base of the caudal-fin rays,
between the dorsal and ventral margins of the caudal peduncle. The new species can also be distinguished from all
congeners by the combination of morphometric, meristic, and pigmentation characters. Comments on other small
species and possible relationships of the new species with its congeners are presented.
Cyphocharax aninha, nova espe´cie, e´ descrita do Rio Mopeco, afluente esquerdo do Rio Paru, afluente esquerdo do baixo
Amazonas. Cyphocharax aninha difere de seus congeˆneres por apresentar canal sensorial infraorbital ausente ou
extremamente reduzido em indivı´duos de grande porte (mais de 30.0 mm SL), recoberto por pele, restrito ao
infraorbitais 5; pela presenc¸a de uma mancha ampla, elipso´ ide, verticalmente alongada sobre o pedu´ nculo caudal e a
base dos raios da nadadeira caudal, que se estende do perfil dorsal ao ventral do pedu´ nculo caudal, formando uma
barra. A nova espe´cie difere tambe´m pela ocorreˆncia simultaˆ nea de caracteres morfome´ tricos, merı´sticos e de padra˜o de
colorac¸a˜o. Comenta´ rios sobre espe´ cies de pequeno porte e possı´veis relac¸o˜es da nova espe´ cie com seus congeˆneres sa˜o
apresentados.
CYPHOCHARAX is the most diverse genus of the
Curimatidae with 37 valid nominal species (Vari,
1992a, 2003; Vari and Blackledge, 1996; Vari and
Chang, 2006; Vari et al., 2010, 2012). The genus is widely
distributed, from southeastern Costa Rica (Central America),
throughout all the major drainages of cis-Andean South
America, to the central part of Argentina (Vari, 1992a). The
distribution of the species in the genus demonstrates
dramatic geographic scales, at one extreme including widely
distributed species such as C. abramoides, which occurs in
the Rio Negro, the upper Rio Orinoco and tributaries of the
lower Rio Amazonas, and C. leucostictus, widely distributed
in the rivers of the Rio Amazonas basin and the coastal rivers
of Amapa´ State, Brazil (Vari, 1992a). Alternatively, the
majority of the species of Cyphocharax have restricted
distributions in specific basins, such as C. aspilos, in the
drainages of Lake Maracaibo (Vari, 1992a), and C. vanderi in
the upper Rio Parana´ (Vari, 1992a), or are endemic to
particular rivers, such as C. pinnilepis, restricted to the Rio
Contas in northeastern Brazil (Vari et al., 2010). Some
species of Cyphocharax are evidently restricted to living in
black, clear or white waters, whereas others can live in all
water types (Vari, 2010). Vari et al. (2012) recently noted the
high number of species of Cyphocharax, as well as of the
overall Curimatidae, in the Guyana Shield, compared to the
rest of South America. These authors proposed the ancient
underlying formation, multiple river captures, variety of
water types, and the incomplete separation of the basins as
factors to explain this diversity. An analysis of a collection
from the Rio Paru in Para´ State, Brazil, allocated to the
Shield, revealed a new species of Cyphocharax, which is
described herein.
MATERIALS AND METHODS
Meristic and morphometric data followed Vari et al. (2012)
and were obtained using calipers with 0.1 mm precision.
Frequency of counts is shown in parentheses after each
count and data for the holotype are indicated via an asterisk.
Cleared-and-stained (CS) specimens were prepared follow-
ing the protocol of Taylor and Van Dyke (1985). Vertebrae
counts were made on CS specimens, with the vertebrae of
the Weberian apparatus, counted as four elements, and the
fused PU1+U1 as a single element. Institutional abbrevia-
tions follow http://asih.org/node/204 and those in the tail
are SL (standard length) and HL (head length).
Cyphocharax aninha, new species
Figure 1, Table 1
Holotype.—MPEG 23609, 35.2 mm SL, Brazil, Para´ , Almeirim
Municipality, Rio Mopeco, left tributary of Rio Paru, left
tributary of lower Rio Amazonas, 0u49924.20N, 53u55946.40W,
30 October 2008, T. M. S. Freitas, L. A. W. Peixoto, and A. B.
Araujo.
Paratypes.—Same data as holotype: INPA 39511, 2, 24.2–
26.8 mm SL; MCP 47850, 2, 25.0–27.6 mm SL; MPEG 15767,
25, 17.1–21.1 mm SL; MPEG 15783, 8, 23.2–38.3 mm SL +8
CS, 16.8–30.0 mm SL; MZUSP 113703, 2, 25.0–28.4 mm SL.
MPEG 15591, 3, 19.9–21.3 mm SL, river no name right
tributary of Rio Mopeco, left tributary of Rio Paru, left
tributary of lower Rio Amazonas, 0u49959.20N, 53u5697.70W,
30 October 2008, T. M. S. Freitas, L. A. W. Peixoto, and A. B.
Araujo. MPEG 15810, 2, 19.9–22.7 mm SL, same data as
MPEG 15591.
Diagnosis.—Cyphocharax aninha differs from its congeners
(except C. vexillapinnus,C. gangamon,C. signatus, and C.
punctatus) in having infraorbital sensory canal absent or
extremely reduced, when present, in largest specimens
(30.0 mm SL), to a fleshy or osseous canal in the
fifth infraorbital (vs. canal always present and complete).
1
Museu Paraense Emı´lio Goeldi, Setor de Ictiologia, Caixa Postal 399, 66040-170, Bele´ m, PA, Brazil; E-mail: (WBW) wolmar@museu-goeldi.br;
and (DPSM) dylriamiranda06@gmail.com. Send reprint requests to WBW.
Submitted: 23 October 2012. Accepted: 30 April 2013. Associate Editor: R. E. Reis.
F2013 by the American Society of Ichthyologists and Herpetologists DOI: 10.1643/CI-12-127
Copeia 2013, No. 4, 627–633

Cyphocharax aninha can be further distinguished from its
congeners (except C. saladensis,C. vexillapinnus,C. signatus,
C. punctatus, and juveniles of C. gangamon) in having four to
nine, modally seven, pored lateral-line scales (vs. more than
ten). Cyphocharax aninha can be further distinguished from
its congeners, except C. santacatarinae, by the presence of a
large, ellipsoid, vertically oriented spot almost forming a bar
at the rear of the caudal peduncle and over the base of the
caudal-fin rays (vs. absence of a spot in C. abramoides,C.
aspilos,C. derhami,C. festivus,C. leucostictus,C. magdalenae,
C. microcephalus,C. multilineatus,C. nagelii,C. nigripinnis,C.
notatus,C. platanus,C. pinnileps,C. plumbeus,C. stilboleps,C.
vexillapinnus, or circular or lozenge-shaped, horizontally
oriented, spot typically concentrated on the center of the
caudal peduncle and not reaching the dorsal and ventral
margins of the peduncle in C. biocellatus, C. gangamon,
C. gilbert,C. gillii,C. gouldingi,C. helleri,C. laticlavius,C.
meniscaprorus,C. mestomyllon,C. modestus,C. oenas,C.
Fig. 1. Cyphocharax aninha, new species, holotype, MPEG 23609, 35.2 mm SL, Brazil, Para´ , Municı´pio de Almeirim, Rio Mopeco, Rio Paru, lower Rio
Amazonas, 0u49924.20N, 53u55946.40W.
Table 1. Morphometric Data of Cyphocharax aninha. Ranges include holotype (n=51). SD =standard deviation.
Holotype Range Mean SD
Standard length (mm) 35.2 17.0–38.5
Percent of standard length
Greatest body depth 39.8 28.2–39.2 34.2 5.5
Snout to dorsal-fin origin 51.1 47.2–56.0 50.9 4.4
Snout to pectoral-fin origin 28.9 27.2–35.3 31.0 4.1
Snout to pelvic-fin origin 50.2 47.6–56.6 74.2 5.9
Snout to anal-fin origin 76.0 67.1–78.7 52.4 4.5
Snout to anus 73.2 67.2–77.7 72.4 5.2
Dorsal-fin origin to hypural joint 59.7 51.6–61.2 56.7 4.8
Dorsal-fin origin to anal-fin origin 46.8 35.1–44.2 40.6 4.6
Dorsal-fin origin to pelvic-fin insertion 38.9 27.2–37.4 32.9 5.1
Dorsal-fin origin to pectoral-fin insertion 38.4 26.4–37.3 31.3 5.5
Caudal-peduncle depth 13.9 10.4–14.1 16.4 5.4
Pectoral-fin length 20.8 10.9–21.6 21.8 4.8
Pelvic-fin length 22.5 17.4–27.1 28.6 4.0
Dorsal-fin length 29.8 24.5–32.5 12.4 1.9
Head length 28.7 27.0–34.2 30.9 3.6
Percent of standard length
Snout length 30.9 22.2–33.5 26.5 5.7
Orbital diameter 35.8 32.2–43.3 36.2 5.6
Postorbital length 42.9 35.4–47.9 41.8 6.2
Interorbital width 41.0 33.1–43.8 37.4 5.3
628 Copeia 2013, No. 4

pantostictos,C. punctatus,C. signatus,C. spilotus,C. piluropisis,
C. spilurus,C. vanderi, and C. voga). Cyphocharax aninha also
differs from C. helleri,C. laticlavius,C. multilineatus, and C.
pantostictos by the absence of series of longitudinal dark
continuous or discontinuous lines on the body (vs. presence
of such pigmentation). Cyphocharax aninha is distinguished
from C. notatus and C. vexillapinnus by the absence of a spot
on the dorsal fin (vs. presence). Cyphocharax aninha differs
from C. biocellatus,C. punctatus,C. vanderi, and C. voga by
the absence of circular or ellipsoid spots on the flanks (vs.
presence). Cyphocharax aninha differs from its congeners,
except C. signatus, in the number of branched pectoral-fin
rays (10–12, rarely 13 or 14 vs. 13 to 17; Vari, 1992a).
Cyphocharax aninha can be further distinguished from C.
signatus by the tip of last branched ray of anal fin not
reaching the base of the caudal-fin rays (vs. reaching).
Cyphocharax aninha can be further distinguished from C.
saladensis by the caudal-peduncle height (10.4–14.4%SL vs.
15.0–17.0; Vari, 1992a), and the interorbital width (33.1–
43.8%HL vs. 44.0–50.0; Vari, 1992a). Cyphocharax aninha
differs from C. spilotus by the distance from snout to anus
(67.2–77.7%CP vs. 78.0–82.0). Cyphocharax aninha addi-
tionally differs from C. santacatarinae in the orbital diameter
(32.2–43.3%HL vs. 26.0–30.0) and by the total number of
vertebrae (30 or 31 vs. 32–34). Cyphocharax aninha can be
further distinguished from C. pinnilepis by the number of
middorsal scales from the supraoccipital process to the
dorsal-fin origin (9 or 10 vs. 11–13).
Description.—Morphometric data summarized in Table 1.
Species small; largest specimen 38.5 mm SL. Body drop-
shaped and compressed laterally, less in larger individuals.
Greater body depth at dorsal-fin origin.
Dorsal profile posterodorsally angled and slightly convex
from snout to dorsal-fin origin; posteroventrally angled and
slightly convex at base of dorsal fin; then nearly straight or
slightly concave toward adipose fin; slightly concave, long
caudal peduncle. Ventral profile of head posteroventrally
aligned and slightly convex from lower lip to isthmus;
convex from isthmus to immediately before pelvic-fin
insertion; convex to anal-fin origin; posterodorsal aligned
and straight or slightly convex along base of anal fin; and
convex along caudal peduncle. Snout profile circular in
dorsal view to anterior margin of orbit; eye profile slightly
convex and emphasized, greatest width over opercular, body
profile straight and compressing gradually to caudal-fin
base. Profiles ellipsoid and compressed at cross sections over
opercular, dorsal-fin origin, anal-fin origin, and at half
caudal peduncle length.
Upper lip larger than lower lip; mouth subterminal.
Nostrils close together; anterior nostril approximately
circular, slightly closer to upper lip than to orbital margin;
posterior nostril transversely elongate, ellipsoid or drop-
shaped.
Eyes approximately circular, center of pupil slightly dorsal
to horizontal line mouth; iris and pupil circular; orbital
margin free.
Scales cycloid, lateral-line scales 29 (5), 30* (18), 31 (13),
32 (11), 34 (1), or 35 (2). Pored lateral-line scales with visible
laterosensory canal system, 4 (3), 5 (11), 6* (13), 7 (18), 8 (4),
9 (1), first at supracleitrum; scales after pored scales, in small
and larger specimens, with vestigial pores frequently
interrupted, no laterosensory canal system, and with ‘‘V’’
notch more pronounced in anterior scales, gradually less
pronounced toward the caudal peduncle. Middorsal scales
from supraoccipital process to dorsal-fin origin, 9* (44) or 10
(6). Transverse series of scales between dorsal fin and lateral
line, 4 (5), 4.5* (34), 5 (7), or 5.5* (5). Transverse series of
scales between anal fin and lateral line, 5* (50). Scales
between anus and anal fin, 1* (28) or 2 (22).
Pectoral fin elongate with i,10* (9), i,11 (15), i,12 (22), i,13
(2), or i,14 (2) rays; first, through third branched rays
longest; largest ray reaches more than one half distance to
pelvic-fin origin . Pelvic fin elongate with i,7 (1); i,8* (43), or
i,9 (6) rays; fin origin just before middle of body,
immediately after point opposite to dorsal-fin origin; first,
second and third largest branched rays, reaching origin of
anal fin.
Dorsal-fin rays, ii,9* (32) or ii,10 (18); dorsal-fin origin mid
length of body; distal margin of fin rounded with first and
second rays longest and approximately twice length of last
ray. Anal fin emarginated, with ii,7 (23) or ii,8* (27) rays;
second unbranched ray two to three times longer than last
ray. Caudal fin forked with ii,15,ii (3); ii,16,ii (13)*, or ii,17,ii
(16) rays; dorsal lobe larger than ventral lobe. Adipose fin
well developed; origin after eighth postdorsal scale; base
over two scales, extending posteriorly over another three
scales; distal margin convex.
Infraorbital series absent in small specimens (less than
21.4 mm SL) or reduced with infraorbitals 1 to 5 extremely
slender and thin. Infraorbital sensory canal absent or
extremely reduced, when present, in large individuals
(30.0 mm SL), restricted to a fleshy or osseous canal in
infraorbital 5.
Total vertebrae, 29 (4) or 30 (4). Precaudal vertebrae, 17 (2)
or 18 (6). Caudal vertebrae, 12 (4), 13 (4). Procurrent dorsal
caudal-fin rays, 3 (4). Procurrent ventral caudal-fin rays
absent (4).
Coloration in ethanol.—Ground color creamy yellow overall
body surface. Dorsal region of body with series of small
chromatophores forming mid sagittal line from tip of
supraoccipital process to caudal-fin base; line darker and
more evident in pre-dorsal region. Dorsal regions of head
and opercular distinctly darker than rest of head. Infraor-
bital region distinctly lighter than interorbital area, with
sparsely distributed stellar chromatophores. Opercule silver
due to retention of guanine and partially covered with
small, densely concentrated chromatophores. Upper lip
covered with chromatophores, slightly more concentrated
along margin forming a dark line. Lower lip partially
covered with chromatophores, more concentrated along
margin. Small chromatophores surrounding posterior re-
gion of orbit. Ventral region of head lightly, colored with
silver regions due to retention of guanine. Abdominal region
with guanine on scales resulting in silver color. Scales on
dorsal and lateral regions of body with small chromato-
phores distributed over entire surface; chromatophores
slightly darker, more concentrated and larger along free
edge, resulting in reticulated pattern; chromatophores
gradually become sparser and fewer ventrally and absent
on ventral scales. Regions near pectoral, pelvic, and anal fins
lighter colored due to absence of chromatophores on scales.
Midlateral region of body, with deep dark indistinct stripe;
stripe origin slightly posterior to operculum, more evident
posterior to dorsal-fin origin to caudal peduncle spot.
Caudal-fin peduncle with conspicuous, large, vertically
oriented, ellipsoid spot, extending between ventral and
Wosiacki and Miranda—A new small species of Cyphocharax 629

dorsal margins of peduncle to form bar on rear peduncle end
and base of caudal-fin rays; width of bar five or six scales on
midline, four scales on dorsal profile and three scales on
ventral profile; central stellar chromatophores larger and
more concentrated, gradually decreasing in size and con-
centration toward edge of spot; in smaller individuals, spot
is sharper and darker. Inter-radial regions with aligned
chromatophores, more concentrated near base of rays.
Dorsal, pectoral, pelvic, adipose, and caudal-fins, hyaline
overall. Dorsal-fin with chromatophores on rays, smaller
and more concentrated on anterior surface of unbranched
and first branched rays, and on distal margin of first to
fourth branched rays. Adipose fin with small chromato-
phores scattered over entire surface. Pectoral-fin with
chromatophores proximate to and on rays. Pelvic fin with
chromatophores on rays. Anal fin with chromatophores
proximate to or on rays, base of fin with darkened regions.
Etymology.—The specific epithet ‘‘aninha’’ is the nickname
of Ana Prudente (MPEG), wife of the first author, and pays
tribute to her contributions toward the understanding of the
Neotropical fauna, specifically the systematics of snakes.
Geographical distribution.—Cyphocharax aninha is known
only from the type locality (Fig. 2), the Rio Mopeco, a left
bank tributary of the Rio Paru, Para´ State, Brazil, near the
eastern border of the ‘‘Amazon’’ area of endemism proposed
by Vari (1988, 1992a) for members of the Curimatidae.
Generic allocation.—No unique synapomorphy for Cypho-
charax has been identified and as such the group has not
been confirmed as monophyletic. Vari (1989) noted that
Cyphocharax is part of a polytomy that also includes
Steindachnerina,Curimatella, and Pseudocurimata,whose
synapomorphies include the loss of a widened ventral
process on the fourth ceratobranchial (character 93; Vari,
1989), the presence of a basihyal toothplate (character 94;
Vari, 1989), the reorientation of infraorbital canals 4 and 5
with consequent reduction of the angle of the primary axis
of this canal (character 95; Vari, 1989), and a reduction of
the sensory canal in infraorbital 6 to a simple tube between
infraorbital 5 and canal of the pterotic segment (character
96; Vari, 1989). Assignment of species to Cyphocharax
involves confirmation of presence of the cited characters
and the absence of synapomorphies for Steindachnerina,
Curimatella, and Pseudocurimata.Cyphocharax aninha is
allocated to the genus because it shares characters 93 and
94 of Vari (1989) for the clade composed by Cyphocharax,
Steindachnerina, Curimatella, and Pseudocurimata and lacks
the synapomorphies for the last three genera of the clade.
Characters 95 and 96 of Vari (1989) are not observed in C.
aninha and are discussed below under Miniaturization.
Cyphocharax aninha is not included in Steindachnerina since
(1) the cartilage of the first infrapharyngobranchial is in
contact with the cartilage of the second infrapharyngobran-
chial but is not expanded as in Steindachnerina (Vari, 1989),
(2) the cartilaginous anterior extremity of the third infra-
pharyngobranchial is in contact with the cartilaginous
extremity of the second infrapharyngobranchial and dis-
tinct from Steindachnerina in which the cartilaginous
extremities of the second and third infrapharyngobranchials
are not in contact (Vari, 1989), (3) the basihyal is elongate,
triangular, and cartilaginous anteriorly and lacks an associ-
ated toothplate, which is distinct from Steindachnerina in
which an association with the toothplate is present (Vari,
1989), and (4) the process for the ligament between the
second and third hypobranchials is absent, versus the
presence of such a process in Steindachnerina (Vari, 1989).
Cyphocharax aninha lacks scales covering the lobes of the
caudal fin as observed in Curimatella (Vari, 1992b). Cypho-
charax aninha differs from Pseudocurimata because: (1) the
first dorsal-fin pterygiophore inserts between the eighth and
ninth neural spine versus between the fourth and fifth
neural spine in Pseudocurimata (Vari, 1989), (2) the joint
cartilage of the second hypobranchial in contact with the
third basibranchial is not divided into anterior and medial
portions versus such a division in the species of Pseudocur-
imata (Vari, 1989), and (3) the uroneural is present as a
single long element along the base of the fourth to sixth
hypurals, versus its absence in Pseudocurimata (Vari, 1989).
Intrageneric relationships.—Preliminary attempts to identify
groups of species in Cyphocharax were based on two systems:
body pigmentation and lateral sensory canal (Vari, 1989).
Cyphocharax aninha shares the presence of a spot on the
lateral surface of the caudal peduncle with C. biocellatus,
C. gangamon,C. gilbert,C. gillii,C. gouldingi,C. helleri,C.
meniscaprorus,C. mestomyllon,C. modestus,C. oenas,C.
pantostictos,C. punctatus,C. saladensis,C. santacatarinae,
C. signatus,C. spilotus,C. spiluropsis,C. spilurus,C. vanderi,
and C. voga. The spot on the caudal peduncle is a common
characteristic in Cyphocharax, varying in size, shape, height,
length and intensity. In C. aninha, the spot on the caudal
peduncle forms a bar covering the base of the caudal-fin
rays, varying in intensity, being sharper and darker in
smaller specimens (up to 17.0 mm SL), to slightly lighter in
the larger individuals (38.5 mm SL), but the standard shape
in the new species relates to that of all specimens.
Another hypothetical grouping among Cyphocharax is C.
saladensis and C. vexillapinnus is based on the reduction of
the laterosensory canal system on the body, regarded as a
derivative condition, and not homologous with the incom-
pletely pored scales of C. punctatus (Vari, 1989, 1992a). Vari
(1992a) did not comment about the condition observed in
C. signatus, despite being described as having ‘‘5 to 7
anterior scales of series with pores’’. The reduction of the
Fig. 2. Map of the lower portions of the Amazon basin and adjoining
area showing type locality of occurrence of Cyphocharax aninha. Dot
represents two localities.
630 Copeia 2013, No. 4

laterosensory canal system on the body is also observed in C.
aninha and the number of pored scales along the anterior
portion of the lateral line scale series is relatively constant
for all small and large specimens and similar to C. saladensis
and C. vexillapinnus as observed by Vari (1992a). Conse-
quently it is distinct from the reduction of the laterosensory
canal system on the body in C. punctatus, commented above
and in Vari (1992a). In C. aninha, the scales after pored
scales present vestigial pores which are not continuous,
being frequently interrupted. In theses scales the laterosen-
sory canal is absent and its posterior margin presents a ‘‘V’’
notch, more pronounced in anterior scales, and gradually
less pronounced toward the caudal peduncle. Therefore, this
is a distinct condition from that observed in C. punctatus.
In Cyphocharax aninha the infraorbital sensory canal is
absent or greatly reduced, even in large individuals (more than
30.0 mm SL) and presents a vestigial fleshy canal restricted to
IO5 (Fig. 3). Therefore, the sensory canal in the first infraor-
bital is absent in C. aninha and shared by C. gangamon, C.
meniscaprorus, C. nigripinnis, C. oenas, C. punctatus, C. saladen-
sis, C. signatus, C. vanderi, and C. vexillapinnus (Vari, 1992a).
However, among these species, C. gangamon, C. meniscaprorus,
C. nigripinnis, C. oenas, and C. punctatus (see Vari, 1992a) plus
C. aninha, exhibit distinctly smaller body size than C.
saladensis, C. vanderi, and C. vexillapinnus.Inthiscontext,Vari
(1992a) observed incongruities among the small and large
species of Cyphocharax and the lack of a laterosensory canal
segment in the first infraorbital, and interpreted the loss of the
canal segment as independent events since it is a typical
feature of diminutive species.
Vari (1992a) observed a derived feature with two sequen-
tial steps related to the sixth infraorbital: the first step, a
reduction of the sixth infraorbital in C. vexillapinnus and C.
gangamon, and the second step, the loss of this bone in
C. signatus and C. punctatus, shared by C. aninha (Fig. 3).
In a broad analysis, presented above, of the derived
features described by Vari (1992a), it is observed that C.
aninha shares with C. signatus the presence of (1) a patch of
dark pigmentation on the midlateral surface of the caudal
peduncle, (2) the incomplete poring of the lateral line, (3)
the absence of a canal in the first infraorbital, (4) the
absence of a sixth infraorbital, and (5) a reduction in body
size. Therefore, it is possible that C. aninha is more related to
C. signatus than to the other species of Cyphocharax.
Miniaturization.—Cyphocharax aninha is likely a small species,
since CS specimens of 16.8–30.0 mm SL (MPEG 15783, 8)
have largely calcified cranial and caudal skeletons. Thus, C.
aninha, whose largest specimen measures 38.5 mm SL, shares
with C. signatus (33.4 mm SL; Vari, 1992a) from the Rio
Vermelho, Goia´s, Brazil, the smallest maximum size within
the genus. Other species of notable small size among this
genus are C. punctatus (42.5 mm SL; Vari, 1992a) from the
upper Marowijne River (Suriname), C. mestomyllon (41.6 mm
SL; Vari, 1992a) from the Rio Negro of the Amazon basin,
Brazil, C. oenas (47.6 mm SL; Vari 1992a) from the central and
western portion of the Rı´o Orinoco basin, Venezuela, C.
gangamon (46.8 mm SL; Vari, 1992a) from Rio Tapajo´s of
the Amazon basin, and C. meniscaprorus (57.0 mm SL; Vari,
1992a) from Rı´o Aro of the Rı´o Orinoco basin.
In their analysis of miniature freshwater species, Weitz-
man and Vari (1988) found a conspicuous reduction in body
size in Cyprinodontiformes, Perciformes and Clupeiformes,
and particularly in Ostariophysi with 88%of the miniature
species in South America being members of Characiformes
and Siluriformes. Weitzman and Vari (1988) also estab-
lished, arbitrarily, that miniature fish species should not
exceed 26 mm SL. The authors, however, emphasized that
miniaturization involves a number of paedomorphic fea-
tures, such as the degree of development of the lateral
sensory canal system of the head and body, a reduction in
the number of fin rays and body scales, and a decrease in the
ornamentation of the bones on the surface of the head.
In terms of body size, C. aninha would not fit the
definition of a miniature species. That said, the species does
demonstrate the following paedomorphic characters: (1)
infraorbitals 1, 2, 3, and 4 when present, very thin, (2) the
absence of a canal in the infraorbital series or reduced, when
present in largest specimens, to a fleshy or osseous canal in
the fifth infraorbital, (3) the incomplete poring of the lateral
line, (4) the absence of the sixth infraorbital, and (5) there is
a tendency towards a reduction in the number of pectoral-
fin rays (i,10–12, rarely i,13 or 14). Vari (1989) listed the
reorientation of infraorbital canals 4 and 5 as the conse-
quent reduction of the angle of the primary axis of this canal
(character 95), and reduction of the infraorbital sensory
canal 6 as a simple tube between infraorbital 5 and the canal
of the pterotic segment (character 96) as a synapomophy for
the terminal polytomy within the Curimatidae. Character
95 (sensu Vari, 1989) is not observed in C. aninha as a result
of the loss of the infraorbital canal in these elements.
Regarding character 96 (sensu Vari, 1989) the sixth infraor-
bital is absent in C. aninha, probably due to an extreme
derived state, resulting from the reduction of its body size.
Among the small species of Cyphocharax above, Vari (1989,
1992a) observed paedomorphic characters related to reduc-
tion or loss of the sixth infraorbital in C. vexillapinnus,C.
gangamon,C. signatus, and C. punctatus, indicating shared
miniaturization as observed in C. aninha. Miniaturization
showing a similar trend related to reduction in body size and
a reduced laterosensory canal system on the body was also
observed in the species of Curimatopsis (Vari, 1982, 1989).
However, as discussed by Vari (1989, 1992), the characters of
miniaturization shared between Cyphocharax and Curima-
topsis are independent acquisitions.
Fig. 3. Infraorbital series of left side of Cyphocharax aninha, new
species, paratype, MPEG 15783. IO1-5 5Infraorbital 1–5. Bar 51 mm.
Wosiacki and Miranda—A new small species of Cyphocharax 631

The eight CS specimens of C. aninha were sexed and none
presented mature testis or gonads to confirm their ontoge-
netic status as adults, probably due to the fact that they were
outside the reproductive period.
MATERIAL EXAMINED
Curimatella dorsalis: Brazil, Para´, MPEG 19942, 5, 23.4–
47.7 mm SL, Rio Tapajo´s.
Curimatella immaculata: All from Brazil, Para´; MPEG 235,
74.6 mm SL, Rio Tapajo´ s. MPEG 234, 45.1 mm SL, Rio
Tapajo´s.
Cyphocharax festivus: MZUSP 41300, 5, 54.0–65.0 mm SL,
paratypes, Peru, Loreto, Rı´o Nanay system, small tahuampa
cocha on left bend above Mishana.
Cyphocharax gangamon: MZUSP 22037, 51.1 mm SL, holo-
type, Brazil, Para´, Monte Cristo, Rio Tapajo´ s, Lagoa de Santa
Clara, 4u49S, 55u389W.
Cyphocharax gouldingi: MZUSP 41762, 97.0 mm SL, holotype,
Brazil, Amapa´, Rio Cuxipi, bridge at road to Serra do Navio
(at channel), 0u409S, 51u409W.
Cyphocharax helleri: MPEG 15734, 1, 35.0 mm SL, Brazil,
Para´, Almeirim; Praia, 0u4990.40N, 53u55943.60S.
Cyphocharax mestomyllon: All from Brazil; MZUSP 41755,
34.9 mm SL, holotype, Amazonas, Rio Negro, Marauia´,
Cachoeira do Bicho-ac¸u, praia. MPEG 20086, 3, 41.0–
67.8 mm SL, Para´, Rio Parauapebas. MPEG 20322, 2, 67.5–
80.2 mm SL, Rio Parauapebas. MPEG 15766, 4, 22.9–
25.6 mm SL, Rio Mopeco. MPEG 15701, 4, 22.7–30.4 mm
SL, Almeirim, Praia, Heliponto, 0u49938.30N, 53u55929.60W.
MPEG 15766, 5, 21.0–24.8 mm SL, Almeirim, Igapo´,
0u49924.20N, 53u55946.40W.
Cyphocharax nigripinnis: MZUSP 42025, 54.47 mm SL,
holotype, Brazil, Roraima, Rio Branco, praia de Xerui, 1uS,
61u509W.
Cyphocharax plumbeus: All from Brazil; MPEG 184, 2, 71.0–
72.0 mm SL, Para´, Rio Tapajo´ s. MPEG 21528, 48.0 mm SL,
Para´, Rio Sacara´ . MPEG 12408, 79.0 mm SL, Amazonas,
Coari, Igarape´ da Onc¸a, left tributary of the Rio Urucu, left
tributary of Rio Coari, right tributary of Rio Solimo˜es,
4u5298.70S, 65u1893.70W.
Cyphocharax signatus: MZUSP 41757, 35.79 mm SL, holo-
type, Brazil, Goia´s, Drenagem Tocantins, Rio Vermelho,
where crossed by road from Aripuana˜ to Britaˆnia, pool along
side of main channel, 15u499000S, 50u199000W.
Cyphocharax spilotus: All from Brazil, Para´, MPEG 15665, 2,
43.9–48.1 mm SL, Rio Mopeco. MPEG 15391, 3, 27.6–
31.7 mm SL, Rio Amazonas. MPEG 15731, 5, 41.5–49.0 mm
SL, Rio Mopeco.
Cyphocharax spiluropsis: MPEG 15328, 2, 53.80–56.38 mm
SL, Brazil, Para´, Rio Amazonas-Nhamunda´.
Cyphocharax spilurus: All from Brazil, Para´, MPEG 15699, 9,
26.9–43.6 mm SL, Almeirim, Praia Heliponto, 0u49938.30N,
53u55929.60W. MPEG 15665, 10, 42.7–45.8 mm SL, Trilha,
0u49943.80N, 53u56953.40W. MPEG 15731, 19, 20.1–54.5 mm SL,
Praia, 0u4990.40N, 53u55943.60W. MPEG 7388, 5, 41.3–53.8 mm
SL, Rio Capim. MPEG 17876, 5, 34.1–49.5 mm SL, Igarape´
Taiassui. MPEG 202, 5, 33.8–60.4 mm SL, Rio Tefe´ . MPEG
7753, 5, 41.5–54.6 mm SL, Rio Tapajo´s.
Cyphocharax sp.: MPEG 15782, 22, 20.1–40.7 mm SL, Brazil,
Para´, Almeirim, Igapo´, 0u49924.20N, 53u55946.40W.
Cyphocharax stilbolepis: MZUSP 41759, 113.70 mm SL,
Holotype, Brazil, Para´, Belo Monte, Rio Xingu, at bottom
of rapids, 3u109S, 5u509W.
Cyphocharax vexillapinnus: Paratypes, MZUSP 41761, 3, 51.4–
57.3 mm SL, Peru, Loreto, Rio Itaya, main river channel and
mouth of can˜ os entering river, 10 km upstream of Bele´m
(Iquitos), 3u519S, 73u129W.
ACKNOWLEDGMENTS
The authors are grateful to the Secretaria Estadual de Meio
Ambiente (SEMA) and Conservac¸a˜o Internacional do Brasil
(CI) for financial support. The Mineradora Rio Tinto (MRT) for
logistic support, and to A. Aleixo the coordinator of the Projeto
Diagno´ stico da biodiversidade das Unidades de C onservac¸a˜o
Estaduais do mosaico Calha Norte do Estado do Para´. L.
Peixoto provided a critical review of the manuscript. T. Freitas,
L. Peixoto, and A. Araujo assisted in the field. WBW thanks the
Conselho Nacional de Desenvolvimento Cientı´fico e Tecno-
lo´ gico (CNP
q
) for the continuous support (processes #304754/
2011-0).
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