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A New Species of Arapaima (Osteoglossomorpha: Osteoglossidae) from the Solim ̃es River, Amazonas State, Brazil

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A new species of Arapaima has been discovered from the central Amazon of Brazil. This new taxon is readily distinguished from all other Arapaima by the following three characters: 1) dorsalmost lateralis sensory cavity on preopercle extremely slender (vs. broadly oval or nearly rectangular in other nominal taxa); 2) ventrolateral margin of head where third infraorbital meets anterior limb of preopercle strongly angled such that ventral surface of head is almost flat (vs. ventrolateral margin of head relatively rounded); and 3) anterior third of dorsal-fin base covered with an enlarged, thickened sheath that hides anterior dorsal-fin rays when adpressed (vs. no thickened sheath on anterior base of dorsal fin and anterior dorsal-fin rays visible when adpressed). Distinguished from all other Arapaima except A. agassizii by having extremely long fourth infraorbital. Distinguished from A. arapaima and all other examined non-type specimens by notably slender body (the holotypes of A. gigas, A. mapae, and A. agassizii also have slender bodies). Further distinguished from A. mapae and A. agassizii by having relatively deep caudal peduncle (6.0% SL, vs. ,4.0% in latter two taxa), and from A. gigas by having dentary teeth in a single row (vs. dentary teeth in 2–2.5 irregular rows). This species was collected near the confluence of the Solimo˜es and Purus rivers in Amazonas State, Brazil. It is the first new species of Arapaima to be described since 1847, and comparisons with Arapaima from Mamiraua´ Reserve demonstrate that there are at least two species of Arapaima present in Amazonas State.
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A New Species of Arapaima (Osteoglossomorpha: Osteoglossidae) from the
Solimo˜es River, Amazonas State, Brazil
Donald J. Stewart
1
A new species of Arapaima has been discovered from the central Amazon of Brazil. This new taxon is readily
distinguished from all other Arapaima by the following three characters: 1) dorsalmost lateralis sensory cavity on
preopercle extremely slender (vs. broadly oval or nearly rectangular in other nominal taxa); 2) ventrolateral margin of
head where third infraorbital meets anterior limb of preopercle strongly angled such that ventral surface of head is
almost flat (vs. ventrolateral margin of head relatively rounded); and 3) anterior third of dorsal-fin base covered with
an enlarged, thickened sheath that hides anterior dorsal-fin rays when adpressed (vs. no thickened sheath on anterior
base of dorsal fin and anterior dorsal-fin rays visible when adpressed). Distinguished from all other Arapaima except A.
agassizii by having extremely long fourth infraorbital. Distinguished from A. arapaima and all other examined non-type
specimens by notably slender body (the holotypes of A. gigas,A. mapae, and A. agassizii also have slender bodies).
Further distinguished from A. mapae and A. agassizii by having relatively deep caudal peduncle (6.0%SL, vs. ,4.0%in
latter two taxa), and from A. gigas by having dentary teeth in a single row (vs. dentary teeth in 2–2.5 irregular rows).
This species was collected near the confluence of the Solimo˜es and Purus rivers in Amazonas State, Brazil. It is the first
new species of Arapaima to be described since 1847, and comparisons with Arapaima from Mamiraua´ Reserve
demonstrate that there are at least two species of Arapaima present in Amazonas State.
THE genus Arapaima Mu¨ller, with type species A. gigas
(Schinz, in Cuvier, 1822), has been considered to be a
monotypic genus for the past 145 years (Ferraris,
2003). That perspective follows from a half-page account by
Gu¨nther (1868), who summarily listed three species de-
scribed by Valenciennes (in Cuvier and Valenciennes, 1847)
in synonymy of A. gigas without rationale or analysis. For
two centuries, Arapaima have been among the most
important commercial fishes in freshwaters of South
America (Castello and Stewart, 2010), but until this year,
no taxonomist has questioned Gu¨nther’s opinion about
these iconic fishes. A review of the scant literature on
species-level taxonomy of Arapaima (e.g., Cuvier, 1822; Spix
and Agassiz, 1829; Schomburgk, 1841; Cuvier and Valenci-
ennes, 1847; Gu¨nther, 1868) and the existing holotypes for
two species of Arapaima in Museum national d’Histoire
naturelle, Paris, revealed that the four nominal species of
Arapaima recognized by Valenciennes appear to be valid
(e.g., Stewart, 2013). In the course of my studies on alpha
taxonomy of Arapaima, I also encountered what appears to
be a new, fifth species of Arapaima represented by a single
specimen from the central Amazon in Brazil.
Recognition of this distinctive fish will allow field
biologists to begin assessing its status and, ultimately, that
could lead to focused management and conservation efforts.
The Purus River and surrounding areas presently are being
fished heavily to supply market demands in Manaus and
other cities of the central Amazon (L. Castello, Woods Hole
Research Center, pers. comm.). It is thus urgent to look more
closely at Arapaima being harvested in that area before
populations are seriously depleted. Aquaculture of Arapaima
also is being developed farther upstream in the Purus basin,
and in time, that may lead to undesirable translocations of
non-native species if possible taxonomic diversity is not
considered (e.g., Castello and Stewart, 2010). In museums of
the world, the total number of preserved arapaima from the
general area where this new species was found can be
counted on one hand, and there are none from the middle
and upper Purus River. Our understanding of the taxonomy
and distributional ecology of Arapaima is substantially
hindered by that paucity of study materials.
Recent observations on morphological variation in a
reference population of Arapaima from Mamiraua´ Reserve,
Brazil, provide a comparative framework for evaluating
those morphometric and meristic features that appear to
be diagnostic for the new species. Examination of the
holotypes of A. gigas and A. mapae, freshly collected
topotypical material for A. arapaima from Guyana, and the
published description of A. agassizii (Spix and Agassiz, 1829;
see re-description by Stewart, 2013) also revealed various
characters that can distinguish the new taxon relative to
those nominal species. Detailed re-descriptions of other
previously described taxa will be published elsewhere, but
characteristics important for a clear, differential diagnosis of
this new species are presented here.
MATERIALS AND METHODS
Comparative materials.—Analyses of the taxonomy of Ara-
paima involve meristic, morphometric, osteological, and
live-color observations on a wide size range of individuals
from Mamiraua´ Reserve in central Brazil (e.g., C. Arantes,
unpubl. data, morphometrics for 28 individuals). Because of
logistic constraints, most large individuals from Mamiraua´
were measured in the field and not retained; preserved
voucher specimens are listed below. Other non-type muse-
um specimens studied were from about 33 localities in the
Amazon basin (n575, from between Bele´ m, Brazil and
Pucallpa, Peru´ ) and from the Essequibo River basin in
Guyana. Further analyses of those data will be published
elsewhere, but they provide a broad context for understand-
ing morphological variation among populations of Ara-
paima; data for particular characters are integrated into the
diagnosis of A. leptosoma by the phrase ‘‘distinguished from
all other.’’ Institutional abbreviations are as listed at http://
www.asih.org/node/204, and the Centre for the Study of
Biological Diversity at the University of Guyana is ‘CSBD/
UG.’
1
Department of Environmental and Forest Biology, College of Environmental Science and Forestry, State University of New York, 1 Forestry
Drive, Syracuse, New York 13210; E-mail: djstewart@esf.edu.
Submitted: 8 February 2012. Accepted: 4 February 2013. Associate Editor: R. E. Reis.
F2013 by the American Society of Ichthyologists and Herpetologists DOI: 10.1643/CI-12-017
Copeia 2013, No. 3, 470–476
Type materials.—Type specimens examined for A. gigas and
A. mapae are as follows; status of the types for A. arapaima
and A. agassizii also are considered; see Stewart (2013) for
additional historical notes.
Arapaima gigas (Schinz, in Cuvier 1822): holotype (also 5
holotype of Vastres cuvieri), MNHN a-8837, 203 cm standard
length (SL), dried and stuffed mount, Brazil, Para´ State,
lower Amazon basin at Villa de Santare´ m, A. R. Ferreira,
between 1783 and 1787 (Ferreira, 1903). This species is
known only from the holotype.
Arapaima mapae (Valenciennes, in Cuvier and Valenci-
ennes, 1847): holotype, MNHN a-8836, 203 cm SL, dried and
stuffed mount, ‘‘lac Mapa, sur les confins des nouvelles
frontie` res de la Guyane franc¸aise’’, purchased by C. Pradier,
a French naval officer, 1837. This locality is now called Lago
do Amapa´ , in Amapa´ State, Brazil. This locality is near the
Atlantic coast and outside the Amazon basin. This species
also is known only from the holotype.
Arapaima arapaima (Valenciennes, in Cuvier and Valenci-
ennes, 1847): holotype, BMNH 2009.1.19.1 (not seen,
presently missing from BMNH, but efforts to find this huge
specimen are continuing, O. Crimmen, BMNH, pers.
comm.), 246 cm total length (when freshly collected), dried,
stuffed specimen, British Guiana, Sir Robert H. Schomburgk,
from his expeditions of 1835–1839; this specimen was
mentioned in Schomburgk (1841) and by Valenciennes (in
Cuvier and Valenciennes, 1847, within the original descrip-
tion of A. arapaima). If the holotype of A. arapaima cannot
be relocated, a neotype from the Rupununi River basin in
Guyana will be designated; that specimen is listed below
under ‘non-type voucher specimens’ and, for various
comparisons, it is referenced here as a ‘topotype.’
Arapaima agassizii (Valenciennes, in Cuvier and Valenci-
ennes, 1847): based on description and illustrations of Spix
and Agassiz (1829:31–40, plate 16, anatomy plates B,
skeleton, and C, scales only), Brazilian Amazon, Spix,
1817–1820 (Spix and Agassiz, 1829; Tiefenbacher, 1983).
This holotype was deposited in Zoologische Staatssammlung
Mu¨nchen, Munich, Germany, but was destroyed in World
War II. See Pethiyagoda and Kottelat (1998) for an English
translation of Spix and Agassiz (1829), and Stewart (2013)
for detailed re-description of this species, which also is
known only from the holotype.
Non-type voucher specimens.—Arapaima arapaima (Valenci-
ennes, in Cuvier and Valenciennes, 1847): topotype, CSBD/
UG 1667, 104 cm SL, alcohol specimen, Guyana, Rupununi
River basin, Grass Pond, ,4.5 km SW from Rewa village,
going upstream along Rewa River, 3.86769uN, 58.76678uW,
L. C. Watson and D. J. Stewart, 12 August 2006.
Arapaima sp. incertae sedis: all of following from Brazil,
Amazonas State, near Comunidade Jaraua´ , Mamiraua´ Sus-
tainable Development Reserve, approximately 2.833uS,
65.000uW, C. Arantes (see Castello, 2008:fig. 1). INPA
26580, approximately 160 cm SL (tail was missing), dry
skull, Parana´ do Jaraua´, close to Comunidade Jaraua´, 13
November 2006; INPA 26581, 126 cm SL, complete dry
skeleton, Lago Samau´ ma, 14 November 2006; INPA 26582,
5, 61.9–73.5 cm SL, 4 alcohol specimens and 1 complete dry
skeleton, Ressaca do Curuc¸a´, 17 November 2006; INPA
26583, 3, 86.6–112 cm SL, 2 alcohol specimens and 1
complete dry skeleton, Lago Samaumeirinha do Jaraqui, 25
November 2006; INPA 26584, 96.8 cm SL, alcohol specimen,
Lago Cedrinho, 24 November 2006.
Morphometric and meristic characters.—Measurements were
made with digital calipers to nearest mm, or for long
measurements on specimens over about 1.0 m SL, to nearest
0.5–1.0 cm using a tape measure. Most measurements follow
standard procedures for fish systematics and are self-
explanatory. Standard length was measured from tip of
upper jaw to mid-point of caudal-fin base. Caudal-peduncle
length is from posterior end of anal-fin base to mid-point of
caudal-fin base. Head length is from tip of upper jaw to tip of
opercular flap; postorbital distance is from posterior bony
margin of orbit to that same point. Length of fourth
infraorbital is from posterior bony margin of orbit to
posterior tip of that bone. Length of upper jaw is from
mid-point of snout to posterior tip of maxilla. Tooth counts
for the dentary are for either the left or right ramus; so total
number of teeth on the lower jaw is double the values
reported here. All tooth counts include gaps where openings
in the skin indicate a missing tooth.
To evaluate statistical significance of morphometric
measures in the context of allometric trends in various
characters, I used comparative measurement data for a wide
size range of Arapaima from a reference population from
Mamiraua´ Reserve, Brazil. Taxonomic status of the Mamir-
aua´ population is a complex problem involving the
superficially similar A. arapaima and beyond the scope of
this paper (for example, they share a relatively deep body
that contrasts with other nominal species of Arapaima and
A. leptosoma). Individual characters were evaluated using
bivariate plots versus SL, and 95%confidence ellipses were
computed for values of the reference population (using
software package PAST Ver. 2.13; Hammer et al., 2001). If
the corresponding value for the holotype of A. leptosoma
falls outside that confidence ellipse, then it can be inferred
that it is different from the reference population. Likewise, if
the value of A. leptosoma is outside and values for type
specimens of other nominal species fall within the 95%
confidence ellipse (or better still, outside in the opposite
direction from A. leptosoma), it can be inferred that they also
are different from A. leptosoma. It is not possible, however, to
directly estimate the statistical probability that two individ-
ual type specimens differ; we can only make indirect
inferences about such differences.
Arapaima leptosoma, new species
Figures 1A–E, 2F
Holotype.—INPA 16847, 77.6 cm SL, Brazil, Amazonas State,
Solimo˜es River about 200 km W of Manaus and 21 km SW of
confluence with Purus River, near Anori, approximately
3.75583uS, 61.67388uW, Manoel Brandas, 25 January 2001;
this is the only known specimen.
Diagnosis.—Distinguished from all other Arapaima by fol-
lowing three characters: 1) dorsalmost lateralis sensory
cavity on preopercle extremely slender (Fig. 2F, vs. broadly
oval or nearly rectangular in other nominal taxa, Fig. 2A–D);
2) ventrolateral margin of head where third infraorbital
meets anterior limb of preopercle strongly angled such that
ventral surface of head is almost flat (Figs. 1E, 2F, vs.
ventrolateral margin of head relatively rounded, Fig. 2E);
and 3) anterior third of dorsal-fin base covered with an
enlarged, thickened sheath that hides anterior dorsal-fin
rays when adpressed (Fig. 1A, vs. no thickened sheath on
anterior base of dorsal fin and distal tips of anterior dorsal-
Stewart—New species of Arapaima 471
fin rays visible when adpressed). Distinguished from all
other Arapaima except A. agassizii by having extremely long
fourth infraorbital (Fig. 3A). Distinguished from A. arapaima
and all other examined non-type specimens by notably
slender body (Figs. 1A, 3B; holotypes of A. gigas,A. mapae,
and A. agassizii also have slender bodies). Further distin-
guished from A. mapae and A. agassizii by having relatively
deep caudal peduncle (6.0%SL, vs. ,4.0 in both of latter two
taxa), from A. gigas by having dentary teeth in a single row
(vs. dentary teeth in 2–2.5 irregular rows), and from A.
agassizii by relatively lower number of teeth on maxilla (28,
vs. 43) and on single ramus of dentary (30–32, vs. 44; see
Stewart, 2013, for additional characters that can distinguish
A. leptosoma from A. agassizii).
Description.—Morphometric characters (as %SL) presented
in Table 1, and meristic counts as follows (counts for
vertebrae, caudal, dorsal, and anal fins based on x-rays):
caudal-fin rays 32 total, approximately 20 branched; dorsal-
fin rays vi,34 or vii,33, 40 total; anal-fin rays iii,35, 38 total;
pectoral-fin rays i,10; pelvic-fin rays i,5; lateral-line scales
52–53; complete scale rows between pelvic-fin origin and
lateral line six; gill rakers (upper limb, first arch) ,12; gill
rakers (lower limb, first arch, including one at angle) ,29;
premaxillary teeth 32; maxillary teeth 28; dentary teeth 30–
32; branchiostegal rays 11; pre-caudal vertebrae 41; caudal
vertebrae 42; total vertebrae 83, including ural centra and
first centrum closely associated with basioccipital.
Dorsal profile of head and body almost straight from tip of
snout to near dorsal-fin origin, slightly upturned posteriorly;
dorsal profile of body along dorsal-fin base sloping gently
downward to caudal peduncle; as noted in diagnosis,
anterior third of dorsal-fin base covered in enlarged, fleshy
sheath; ventral profile of head and body as continuous,
gentle convex arc from tip of dentary to caudal peduncle
(curvature may be partially an artifact of preservation).
Dorsal fin originates just anterior to anal-fin origin,
relatively low with longest rays in posterior half of fin;
rounded posteriorly, with posterior rays extending beyond
caudal-fin base when adpressed. Caudal fin with dorsal and
ventral margins distinctly rounded, forming broad vertical
ellipse. Adpressed pectoral fin extends about 36%of distance
from its origin to pelvic-fin insertion, inserted low on body
with base oriented almost horizontally (Fig. 2F; this may be
a diagnostic feature that correlates with flattened underside
of head and flattened breast; compare to angled pectoral-fin
base in a Mamiraua´ specimen, Fig. 2E); first pectoral-fin ray
unbranched, slightly shorter than first branched ray,
posterior margin of pectoral fin distinctly rounded with
rays 4–6 longest. Pelvic fin inserted about two-thirds of
distance between tip of snout and caudal-fin base; outer,
unbranched ray shorter than first branched ray; posterior
margin of fin rounded with rays 3–4 longest; adpressed
pelvic fin extends posterior to about 60%of distance from
its origin to anal-fin origin; pelvic fin folds longitudinally
between rays 3 and 4 when retracted against ventrolateral
margin of body (as is typical of most Arapaima). Anus
situated about midway between posterior tip of pelvic fin
and anal-fin origin, but slightly closer to pelvic-fin tip. Anal
fin inserts just posterior to dorsal-fin origin, with its
posterior tip rounded and overlapping caudal-fin base when
adpressed.
Mouth distinctly upturned with opening nearly superior,
mandible extends beyond tip of snout a distance about one
third of orbit diameter; mouth opening large and nearly as
wide as snout; maxilla extends posteriorly almost to below
center of orbit. Vomerine tooth-patch distinctly separated
from tooth-patch on the parasphenoid. Eyes lateral to
slightly dorsolateral, centered about one fifth of distance
from tip of snout to tip of opercular flap (when seen in
lateral profile). Opercular flap extends to posterior margin of
cleithrum, not overlapping onto scales posterior to that or
Fig. 1. Arapaima leptosoma, holotype: (A) lateral view, arrow indicates approximate position of dorsal-fin origin, and (B) ventral view to show
relative size and position of pectoral and pelvic fins, scale bar 510 cm; (C) dorsal view, and (D) ventral view of head, scale bar 510 cm; and (E)
ventrolateral view of head to illustrate angular junction of preopercle (pop) and third infraorbital (io3); arrows indicate where those two bones meet,
scale bar 55 cm.
472 Copeia 2013, No. 3
Fig. 2. Comparisons of shape for dorsalmost lateralis cavity on preopercle for: (A) A. gigas, holotype; (B) A. arapaima, topotype, Guyana (CSBD/UG
1667); (C) A. mapae, holotype; (D) A. agassizii, holotype; (E) juvenile Arapaima sp. from Mamiraua´ Reserve, Brazil (INPA 26582, 61.9 cm SL); and
(F) A. leptosoma, holotype; scale bars for A, C, E, F 55 cm; for B, D 52 cm.
Stewart—New species of Arapaima 473
onto pectoral-fin base. Gill membranes overlap broadly
along ventral midline, free from isthmus. Anterior and
posterior nostrils situated on dorsum of snout; anterior
nostril about midway between tip of snout and anterior
margin of orbit, with short, unpigmented flap or papilla on
posterior margin. Dorsal surface of head with numerous,
irregular, bony ruggosities, not organized into clear longi-
tudinal or transverse striations; likewise, third infraorbital
lacking clearly developed longitudinal striations, and stria-
tions only weakly developed on fourth infraorbital (vs.
various other Arapaima having distinct longitudinal stria-
tions on various bones of head; e.g., Fig. 2A, D).
Color in alcohol.—The following description of color patterns
is based on the holotype, which was preserved in formalin
and subsequently transferred to ethanol for permanent
storage. Dorsal surface of head and body from near tip of
snout to posterior end of dorsal-fin base dark, dusky gray. Side
and ventrum of head below ventral margin of orbit and flank
below lateral line lighter colored from mandible posteriorly
to about anal-fin origin (perhaps white, silvery or cream-
colored in life); flank darker between bases of dorsal and anal
fins. Lighter pigment on posterior margins of scales along
dorsal- and anal-fin bases, forming narrow streaks that angle
anteriorly (Fig. 1A; in most live Arapaima of other species that
I have seen, the light-colored scale edges and spots on the
median fins range in color from pink to red).
Dorsalfindarkgraywithrelativelylarge,vertically
elongate spots on posterior third. Caudal fin and peduncle
with similar dark gray base color; large, sub-marginal spots
arranged in arc around posterior margin of caudal fin; distal
tips of middle caudal-fin rays darker, almost black (Fig. 1A).
Most of anal fin uniformly dark, almost black, but lighter
colored near origin. Both pectoral and pelvic fins lightly
pigmented, perhaps white or silvery in life and matching
lower flank and belly.
Etymology.—From the Greek leptos, slender, and soma, body,
in reference to the relatively slender body form of this
species.
DISCUSSION
This is the first new species of Arapaima to be described since
1847. It can be separated readily from the Mamiraua´
population (e.g., Fig. 2E, F), so it is clear that there are at
least two species of Arapaima in the central Amazon.
Arapaima gigas is the only freshwater fish in South America
listed as an endangered species (i.e., CITES, Appendix II; but
‘Data Deficient’ according to IUCN, 2011). My review of
materials of Arapaima in museums did not yield a second
specimen of A. gigas, so its known distribution presently is
limited to the type locality near Santare´ m, Para´ State, Brazil.
An important implication is that neither A. leptosoma nor
the Mamiraua´ population is protected under international
conventions; the same is true for A. mapae, A. agassizii, and
Fig. 3. Bivariate plots for: (A) fourth infraorbital length, and (B) body
depth at pelvic-fin origin, comparing values for 28 specimens from
Mamiraua´ Reserve (dark dots, and shaded areas 5associated 95%
confidence ellipses) with holotypes for four species of Arapaima:L5A.
leptosoma,G5A. gigas,M5A. mapae,Ag5A. agassizii, and with a
topotype of A. arapaima 5Ar.
Table 1. Morphometric Characteristics (as %SL) for the Holotype of
Arapaima leptosoma.
Character
Holotype
INPA 16847
Total length, cm 83
Standard length, cm 77.2
Predorsal length 71.3
Dorsal-fin base length 26.6
Longest dorsal-fin ray 9.1
Preanal length 78.4
Anal-fin base length 25.5
Longest anal-fin ray 6.9
Pre-pelvic length 64.1
Pelvic-fin length 8.5
Width between pelvic-fin origins 4.7
Pre-pectoral length 26.6
Pectoral-fin length 14.1
Pectoral-fin origin to pelvic-fin origin 39.0
Body depth at pelvic-fin origin 14.2
Pelvic-fin origin to dorsal-fin origin 18.5
Caudal-peduncle depth 6.0
Caudal-peduncle length 4.1
Caudal-fin height 10.1
Head length (to tip opercular flap) 26.6
Head depth (at occiput) 10.4
Head depth (at orbit) 7.0
Head width (across operculi) 12.6
Interorbital width 5.7
Width between anterior nostrils 3.8
Mouth width (at rictus) 7.3
Bony orbital diameter 2.8
Snout length 5.2
Preorbital distance 1.3
Fourth infraorbital length 10.1
Postorbital length 18.4
Upper jaw length 7.5
Mandible length 10.8
Premaxillary tooth-row width 4.5
474 Copeia 2013, No. 3
A. arapaima. Another implication is that, like many other
fish genera in the Amazon (e.g., Kullander and Ferreira,
2006), Arapaima may include common (e.g., Mamiraua´
population) or wide-spread species together with rare or
geographically restricted species (Castello and Stewart, 2010;
Stewart, 2013). It is time to set aside the idea that the genus
Arapaima is represented only by one, panmictic species (e.g.,
Gu¨ nther, 1868; Hrbek et al., 2005; Araripe et al., 2013).
The Mamiraua´ population has been estimated to number
in the tens of thousands, but that is among the very few
areas in the Amazon where good population count data
exist (Castello et al., 2011). That is also an area where
populations have recovered following implementation of
community-based management programs. Elsewhere, espe-
cially around large cities, populations were seriously deplet-
ed as early as the 1920s (e.g., Eigenmann and Allen, 1942;
Neves, 1995). If species distributions are restricted, then
some taxa could be severely threatened, but available data
are insufficient to judge such matters.
Fortunately for A. leptosoma, substantial protected areas
have been established along the lower Purus River (i.e.,
Reserva de Desenvolvimento Sustenta´vel Piagac¸u-Purus with
about 7,900 km
2
and the smaller but contiguous Reserva
Biolo´ gica de Abufari). It seems likely that A. leptosoma will
persist in those areas because the extensive va´ rzeahabitat with
numerous lagoons is ideal for Arapaima. Its rarity in museum
collections probably reflects insufficient collecting efforts in
the Purus River and adjacent areas of the Solimo˜ es River.
Collecting adult Arapaima involves considerable difficulties,
both with logistics in the field and subsequent storage in
museums. As this study demonstrates, however, collecting at
least a few voucher specimens can greatly enhance our
knowledge of these fascinating fishes. Many more are needed.
Arapaima have high economic, cultural, and scientific value,
but their diversity has been overlooked for too long.
ACKNOWLEDGMENTS
This research was supported, in part, by National Geograph-
ic Society and SUNY College of Environmental Science and
Forestry. Unpublished morphometric and meristic data from
Mamiraua´ , Brazil, were provided by C. Arantes, Instituto de
Desenvolvimento Sustenta´ vel Mamiraua´ . Librarians at Cor-
nell University, MCZ, and AMNH provided access to rare
books. Assistance arranging for x-rays in Manaus was
provided by L. Rapp Py-Daniel. For assistance during
museum visits, I thank: P. Pruvost, MNHN; O. Crimmen,
BMNH; K. Hartel, MCZ; B. Brown, AMNH; M. Rogers,
FMNH; J. Williams, USNM; L. Rapp Py-Daniel, INPA; M. de
Pinna, MZUSP; P. Buckup, MNRJ; W. Wosiacki, MPEG; R.
Barriga, EPN; H. Ortega, MNHJP; C. Bernard, CSBD/UG, and
many others. The Brazilian (IBAMA-Manaus) research
permit to C. Arantes for collecting Arapaima at Mamiraua´
was #02005.0021/06-67.
LITERATURE CITED
Araripe, J., P. S. d. Reˆgo, H. Queiroz, I. Sampaio, and H.
Schneider. 2013. Dispersal capacity and genetic structure
of Arapaima gigas on different geographic scales using
microsatellite markers. PLoS ONE 8(1):e54470. doi:10.1371/
journal.pone.0054470.
Castello, L. 2008. Lateral migration of Arapaima gigas in
floodplains of the Amazon. Ecology of Freshwater Fish
17:38–46.
Castello, L., and D. J. Stewart. 2010. Assessing CITES non-
detriment findings procedures for Arapaima in Brazil.
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... é uma das espécies de peixes mais visadas, fato bastante relacionado ao seu peso que pode atingir 200 kg e ao seu tamanho que pode chegar a três metros de comprimento; ele é considerado um dos maiores peixes de água doce do planeta, com uma taxa de crescimento que chega a 10 kg/ ano. É uma espécie pertencente ao gênero Arapaima, esse que, durante anos, foi considerado monotípico e dispunha apenas da espécie Arapaima gigas, no entanto, posteriormente, foram dispostas as espécies Arapaima agassizii (VALENCIENNES, 2022a), Arapaima mapae (VALENCIENNES, 2022b) e Arapaima leptosoma (STEWART, 2013), fato ...
... ainda debatido por alguns autores que as classificam como A. gigas apenas e evidenciam a dificuldade de identificação taxonômica e distribuição geográfica da espécie (IMBIRIBA, 2001;JESUS;BEZERRA;SANTOS, 2021;STEWART;ARANTES, 2013). ...
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... Ichthyologist Albert Günther (1868) declared with no rationale that it was the only valid species, a view that persisted for over 100 years only because scientists never questioned his claim. However, as many as three other species of Arapaima have been recently named in Brazil, Peru, and Guyana (Stewart 2013a(Stewart , 2013b. The most recent was Arapaima leptosoma, found in the Solimões River in Brazil. ...
... Stewart admonishes other scientists to "Beware of conventional wisdom-what we know might be completely wrong" (Stewart 2013a). ...
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... Giant salamanders are one of several threatened large charismatic vertebrate taxa now known to comprise multiple species (Hekkala et al. 2011, Stewart 2013, Murray et al. 2019, Downloaded from https://academic.oup.com/evolinnean/advance-article/doi/10.1093/evolinnean/kzae007/7690816 by Chengdu Institute of Biology, CAS user on 15 July 2024 A c c e p t e d M a n u s c r i p t Coimbra et al. 2021). Molecular methods play an increasing role in delimiting such species and understanding evolutionary relationships (Vogler and Monaghan 2007), and have recently been used to reveal unexpected diversity in other highly threatened groups (e.g. ...
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Arapaima are listed as endangered fishes according to the Convention on International Trade of Endangered Species of Wild Fauna and Flora (CITES), thus their international trade is regulated by non-detriment finding (NDF) procedures. The authors critically assessed Brazil’s regulations for NDF procedures for Arapaima using IUCN’s checklist for making NDFs, and found that those regulations cannot ensure the sustainability of Arapaima populations. Arapaima are among the largest fishes in the world, migrate short distances among several floodplain habitats, and are very vulnerable to fishing during spawning. They are threatened mainly by overfishing. The fishery is largely unregulated because government regulations on size, season, and even moratoriums on capture have been very poorly enforced. Arapaima remain poorly understood and the taxonomy and geographical distribution of the genus remain uncertain. There are no data on catch levels or status of wild populations, although available information suggests they are in decline. Brazil’s NDF procedures for specimens originating in the wild are inadequate as they rely on ‘technical opinion reports’, which do not necessarily require scientific evidence. Furthermore, Brazil’s NDF procedures exempt the need for NDF reports on ‘captive’ specimens; however, ‘captive’ specimens originating in the wild and raised in captivity can be exported because regulations do not specify that they must be ‘captive-bred’. Six suggestions are offered to improve the reliability of NDF procedures for Arapaima in Brazil, emphasizing the utility of participatory monitoring and adaptive harvesting to strengthen much needed harvest control capacity in other tropical fisheries.
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Abstract – This study deduced in detail the lateral migration –those between river channels and floodplain habitats – of the pirarucu (Arapaima gigas), a giant, obligate air-breathing species of the Amazon Basin. Over a thousand samples of the pirarucu were taken through counts of the individuals performed at the moment of aerial breathing; these samples were taken in eight habitats of a floodplain near the Amazon River every week throughout an entire flood cycle. The lateral migration of the pirarucu accompanied water level fluctuations closely. As water levels rose, the pirarucu migrated to increasingly higher habitats in flooded forests and remained there during high water levels. As water levels declined, the pirarucu migrated first back to lower habitats of flooded forests, then to communicating channels, and, eventually, to the lakes, where they remained during low water levels. These results allow for a conceptual model of lateral migration of floodplain fishes.