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Sternarchella calhamazon n. sp., the Amazon's Most Abundant Species of
Apteronotid Electric Fish, with a Note on the Taxonomic Status of Sternarchus
capanemae Steindachner, 1868 (Gymnotiformes, Apteronotidae)
Author(s): John G. Lundberg Cristina Cox Fernandes Ricardo Campos-Da-Paz John P. Sullivan
Source: Proceedings of the Academy of Natural Sciences of Philadelphia, 162():157-173. 2013.
Published By: The Academy of Natural Sciences of Philadelphia
DOI: http://dx.doi.org/10.1635/053.162.0110
URL: http://www.bioone.org/doi/full/10.1635/053.162.0110
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PROCEEDINGS OF THE ACADEMY OF NAT UR A L SCIENCES OF PHILADELPHIA 162: 157-173 MARCH 2013
Sternarchella calhamazon n. sp., the Amazon’s most abundant species of apteronotid electric
ÀVK ZLWK D QRWH RQ WKH WD[RQRPLF VWDWXV RI Sternarchus capanemae Steindachner, 1868
(Gymnotiformes, Apteronotidae)
JOHN G. LUNDBERG
Department of Ichthyology, The Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA 19103-1195 USA.
E-mail: lundberg@ansp.org
CRISTINA COX FERNANDES
Biology Department, Morrill Science Center, University of Massachusetts, Amherst MA, 01003, USA, and Instituto Nacional de
Pesquisas da Amazônia, Manaus, BRAZIL.
E-mail: cristina@bio.umass.edu
RICARDO CAMPOS-DA-PAZ
Laboratório de Ictiologia Neotropical, Departamento de Ecologia e Recursos Marinhos, Instituto de Biociências, Universidade Federal
do Estado do Rio de Janeiro, Av. Pasteur 458/408, Urca - Rio de Janeiro - RJ, 22290-240, BRAZIL.
E-mail: rcamposdapaz@gmail.com
JOHN P. SULLIVAN
Department of Ichthyology, The Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA, 19103-1195 USA.
Present address: Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA.
E-mail: jpsullivan@cornell.edu
$%675$&7³$QHZ VSHFLHVRIDSWHURQRWLG HOHFWULFÀVKLV GHVFULEHGIURPWKH %UD]LOLDQDQG3HUXYLDQ$PD]RQSternarchella
calhamazon sp. n. conspicuously differs from its congeners in caudal peduncle shape, electric organ size and shape, hemal spine
HORQJDWLRQDERYHWKHDQDOÀQDQGDUUDQJHPHQWRILQWHUPXVFXODUERQHVDGMDFHQWWRWKHHOHFWULFRUJDQSternarchella calhamazon
LVDPRQJ WKH PRVWFRPPRQ J\PQRWLIRUPVSHFLHV OLYLQJLQWKH SULQFLSDOFKDQQHOV RIWKHORZODQG$PD]RQ 5LYHUDQG LWV ODUJH
tributaries.
The nominal apteronotid Sternarchus capanemae 6WHLQGDFKQHULVDQHDUOLHUSXEOLVKHGREMHFWLYHV\QRQ\PRISternarchella
schotti Steindachner, both names appearing in 1868. Because S. capanemae ZDVQHYHU XVHGDVD YDOLGQDPHDIWHULWVÀUVWXVHLW
should be considered a nomen oblitum and Sternarchella schotti should be considered a nomen protectumDQGWKHYDOLG QDPHRI
this species.
ISSN 0097-3157
INTRODUCTION
Eigenmann (in Eigenmann and Ward, 1905) established
the apteronotid genus Sternarchella for the nominal species
Sternarchus schotti Steindachner, 1868b and Sternarchus
balaenops Cope, 1878. Sternarchus schotti, based on a
specimen from “Barra do Rio Negro” (= mouth of the rio
Negro), near Manaus, Brazil, was designated as the type
species of the genus. Sternarchus balaenops was based on
a specimen from the Peruvian Amazon (Eigenmann and
Ward, 1905:164). Sternarchella ZDV ÀUVW VHSDUDWHG IURP
Sternarchus (= Apteronotus Lacépède) in a “Key to the
genera of Gymnotidae” in Eigenmann and Ward, (1905:160)
on the basis of its short gape and snout (vs. “gape long” and
“snout long” in other nominal Sternarchus). Later in that
same contribution (Eigenmann and Ward, 1905:163), it was
also pointed out that in Sternarchella “[t]he snout is much
shorter and the mouth is very much smaller” (i.e., when
compared to Sternarchus albifrons [= Apternotus albifrons
(Linnaeus)]. The same diagnostic features Sternarchella
were restated by Ellis (1913), who called attention to the
“gape short” and “gape not reaching the posterior nostril”
in that genus (1913:150).
Mago-Leccia (1994), Albert and Campos-da-Paz
(1998) and Albert (1995, 2001) developed a phylogenetic
diagnosis of SternarchellaWKDWLQFOXGHVÀYHXQDPELJXRXV
synapomorphies among Apteronotidae: gape of mouth very
short, less than twice the eye diameter; maxilla crescent
shaped; maxillary anterior process and anteroventral
PDUJLQ XQRVVLÀHG JLOO UDNHUV ÀUPO\ DWWDFKHG WR JLOO
158 J.G. LUNDBERG,C.COX FERNANDES,R.CAMPOS-DA-PAZ & J.P. SULLIVAN
DUFKHVJLOOUDNHUWLSV FRYHUHG ZLWKÀEURXV FDSV )XUWKHU
the close phylogenetic relationship between Sternarchella
and Magosternarchus has been demonstrated by Albert in
Lundberg et al. (1996), Albert and Campos-da-Paz (1998),
$OEHUWDQG,YDQ\LVNL
In addition to the type species S. schotti,we
UHFRJQL]H ÀYH VSHFLHV RI Sternarchella as valid: S.sima
6WDUNV S.terminalis (Eigenmann and Allen 1942),
S. curvioperculata Godoy 1968 (but see Discussion
below), Sternarchella orinoco Mago-Leccia 1994 and S.
orthos Mago-Leccia 1994. Although recently treated as a
synonym of S. sima (Albert 2001, 2003), reexamination
of Sternarchella orinoco E\ ,YDQ\LVNL LQGLFDWHV
that the two nominal species are distinct. Sternarchella
balaenops was properly transferred to Adontosternarchus
Ellis by Eigenmann and Allen (1942, see Mago-Leccia et
al., 1985).
7KH SX]]OLQJ VSHFLHV GLYHUVLW\ DQG LGHQWLÀFDWLRQ
of Sternarchella ZDV ÀUVW HQFRXQWHUHG E\ -*/ )
Mago-Leccia and E. Marsh-Matthews while examining
specimens collected during the 1978-1979 Orinoco Delta
Expeditions (Mago-Leccia, 1994). Occasional references
WR XQQDPHG VSHFLHV RU XQFHUWDLQ LGHQWLÀFDWLRQV RI
SternarchellaIXUWKHUVXJJHVWHGDQLQFRPSOHWHNQRZOHGJH
RI VSHFLHV GLYHUVLW\ LQ WKH JHQXV &R[ )HUQDQGHV
$OEHUW &R[ )HUQDQGHV HW DO 2XU
current interest in Sternarchella emerged from analyzing
material of four distinct species collected during the
“Calhamazon Project’s” ichthyological exploration of the
FKDQQHOVRI WKH%UD]LOLDQ$PD]RQ&R[)HUQDQGHV
/XQGEHUJHW DO7KHVH VSHFLHVDUHLGHQWLÀHG
now as S. schotti,S.sima,S.terminalis and the new species
GHVFULEHG KHUH :H DOVR ÀQG DQG LOOXVWUDWH DGGLWLRQDO
specimens of Amazonian Sternarchella that are similar to
S.terminalisH[FHSW IRUYDULDEO\FRQFDYHKHDGSURÀOHVRI
XQFHUWDLQWD[RQRPLFVLJQLÀFDQFH
)LQDOO\ZHSUHVHQWDEULHIGLVFXVVLRQRIWKHWD[RQRPLF
status of Sternarchus capanemae Steindachner, 1868.
This scarcely discussed nominal species was previously
referred to as a junior synonym of S. schotti (Albert, 2001).
MATERIAL AND METHODS
The Brazilian specimens of Sternarchella examined
in this study were collected during the “Calhamazon
3URMHFWµDQGRWKHUÀHOGRSHUDWLRQVUXQE\UHVHDUFKHUVDWWKH
Instituto Nacional de Pesquisas da Amazônia (INPA). The
Peruvian specimens were collected by M. Sabaj Pérez and
colleagues on collecting trips to the Amazon near Iquitos
and the Nanay River. Specimens from the Orinoco were
collected during the late 1970s R/V Eastward Orinoco
Delta Expeditions (López et al., 1984; Mago-Leccia et
al., 1985; Mago-Leccia, 1994). Ichthyological collection
codes follow Sabaj Pérez (2012).
Measurements were made with dial calipers and
generally follow Lundberg et al. (1996): total length (TL),
standard length (SL), length from snout tip to end of
DQDOÀQEDVH/($ GLVWDQFH IURPVQRXWWLS WR RULJLQRI
GRUVDOÀODPHQW/2'DQDOÀQEDVHOHQJWK$)%FDXGDO
peduncle length; caudal peduncle depth at the posterior
HQG RI WKH DQDO ÀQ HOHFWULF RUJDQ GHSWK DW WKH SRVWHULRU
HQGRIWKHDQDOÀQOHQJWK IURPVQRXWWLSWRRULJLQRIDQDO
ÀQOHQJWK IURPVQRXW WLSWRDQXVXURJHQLWDOSDSLOODKHDG
length to dorsal end of gill membrane; head length to
dorsoposterior corner of opercle (HL); postorbital head
length from posterior margin of eye to insertion of leading
SHFWRUDOÀQ UD\ ERG\ GHSWK DW RULJLQ RI GRUVDO ÀODPHQW
maximum body depth; head depth at occiput; snout length;
length from eye to chin tip; eye diameter; length from eye
to anterior naris; interorbital distance.
&RXQWV ZHUH PDGH RI WRWDO ÀQ UD\V LQ WKH DQDO
FDXGDODQGSHFWRUDOÀQV9HUWHEUDOFRXQWVLQFOXGHWKHIRXU
HOHPHQWVRIWKH:HEHULDQFRPSOH[WKHÀUVWFDXGDOYHUWHEUD
is articulated with the anterior displaced hemal spine
(Albert, 2001; = posteroventral abdominal bone, Hilton et
al., 2007) and posterior series of displaced hemal spines
(Albert, 2001); the last caudal vertebra counted has its
KHPDOVSLQHDVVRFLDWHGZLWKWKHODVWDQDOÀQSWHU\JLRSKRUH
9HUWHEUDODQGVHYHUDODQDOÀQUD\ FRXQWVZHUHPDGHIURP
radiographs and cleared/stained preparations, excluding
specimens found to have damaged or regenerated tails.
3KRWRJUDSKV SUHSDUHG DW $163 ZHUH WDNHQ ZLWK D
1LNRQ ' ZLWK &DPHUD &RQWURO 3UR WR SURGXFH
images differing only in focal plane. These image sets
ZHUHSURFHVVHGZLWK+HOLFRQ)RFXVVRIWZDUHWRSURGXFH
VLQJOHLQIRFXVLPDJHVZLWKPXFKLPSURYHGGHSWKRIÀHOG
'LJLWDO UDGLRJUDSKV ZHUH WDNHQ DW $163 ZLWK D .HYH[
0LFUR)RFXV ;5D\ 6RXUFH DQG 9DULDQ 3D[6FDQ LPDJH
receptor.
Electric organ discharges (EODs) of four specimens
of Sternarchella calhamazon and eight of S. terminalis,
three of Magosternarchus duccis and two of M. raptor
were recorded during the 1993 Calhamazon Project expe-
dition on board the R/V Almirante Guimaräes in a 10 cm x
40 cm x 12 cm aquarium with silver/silver–chloride elec-
trodes positioned at the ends and a reference electrode in
WKHFHQWHU(2'VZHUHDPSOLÀHGXVLQJD&:(&RUSRUDWLRQ
ELR²DPSOLÀHUZLWKÀOWHUVVHWWR+]WR+]XVLQJ
ORZ JDLQ DQG FDSWXUHG ZLWK D 7HNWURQL[ GLJLWDO VWRU-
age oscilloscope (512 point/8-bit resolution). Recordings
were made in water from the capture locality at ambient
WHPSHUDWXUHV²& ZLWKWKH ÀVKIDFLQJ WKHSRVLWLYH
electrode such that head positivity was displayed as posi-
tive voltage on the oscilloscope.
NEW STERNARCHELLA KNIFEFISH 159
Sternarchella calhamazon n. sp. Lundberg,
&R[)HUQDQGHV&DPSRVGD3D]
)LJV$%$7DEOH
Sternarchella terminalis³/XQGEHUJ &R[ )HUQDQGHV
Albert and Garcia, 1996 (Brazil; morphology); Cox
)HUQDQGHV%UD]LO$PD]RQ5LYHU
Sternarchella VS³&R[)HUQDQGHV3RGRVDQG/XQGEHUJ
2004 (Brazil, Amazon River).
Sternarchella VS³&R[ )HUQDQGHV /XQGEHUJ DQG
Sullivan, 2009 (cytochrome b gene sequence comparisons;
voucher specimen catalog number here corrected as ANSP
189210).
Holotype.—INPA 37898, 162.8 mm TL male, Brazil,
$PD]RQDV 6WDWH ULR 0DGHLUD NP DERYH FRQÁXHQFH
with rio Amazonas, collected with 3 m bottom trawl in
FKDQQHO PGHHS PRII OLQHDUEHDFK DQGEDQN
3°35’44.2”S, 58°57’45.8”W, 6 Aug 1996, Zanata et al.
)LHOGQR$0= &ROOHFWHG ZLWKRQHSDUDWRSRW\SH
INPA 37899, see below.
Paratypes.—Twenty-nine lots containing overall 42 paratype
VSHFLPHQV DUH OLVWHG JHRJUDSKLFDOO\ E\ FRQÁXHQFH DUHDV RI
PDMRU$PD]RQWULEXWDULHVLQ(DVWWR:HVWRUGHU)LJ%5$-
=,/3DUi6WDWH 5LR ;LQJX DUHD$163
PP7/IHPDOHVULR$PD]RQDVEHORZ;LQJXFROOHFWHG
ZLWK P ERWWRP WUDZO ZLWK Á\VFUHHQ OLQHU LQ FKDQQHO
P GHHS PRIIOLQHDUEDQNZLWKIRUHVW·µ6
·µ:1RY)LHOGQR$0==DQDWD
et al. Rio Tapajos area - MZUSP 111953, 1, 147.8 mm TL, rio
Amazonas below Tapajos, collected with 3 m bottom trawl in
FKDQQHOPGHHSPRIIOLQHDUVDQG\EDQNZLWKJUDVV
DQGVKUXE ··¶6··¶: 1RY)LHOG
no. AMZ-94-010, Zanata et al. MZUSP 111954, 2, 95.1-145.3
mm TL, male, rio Amazonas below Tapajos, collected with 3
m bottom trawl in channel, 28- 23 m deep, 150 m off sandy
EDQN ZLWK JUDVV DQG VKUXE ··¶6 ··¶:
1RY)LHOGQR$0==DQDWDHWDO%5$=,/$P-
D]RQDV6WDWH5LR7URPEHWDVDUHD)01+
mm TL, female, rio Amazonas below Trombetas, collected
with 3 m bottom trawl in channel, 12.8 -5.3 m deep, 150-200
m off linear muddy beach with grass and shrub, 2°02’45.7’‘S,
··¶:2FW)LHOGQR0:::HVW-
neat et al. Rio Madeira area - LACM 57530-1, 1, 119.9 mm
TL, male, rio Amazonas above rio Madeira, collected with 3
m bottom trawl in channel 12.5-10 m deep, 500 m off concave
EDQNRIVPDOO SDUDQD ··¶6··¶:2FW
)LJ/DWHUDOYLHZRISternarchella calhamazon holotype, INPA 37898. A. whole specimen, B. head and anterior body; C. tail showing
WUDQVSDUHQWHOHFWULFRUJDQZLWKWZRURZVRILQWHUPXVFXODUERQHVP\EYYHQWUDOP\RUKDEGRLIEYYHQWUDOVHULHVRIÀODPHQWRXVERQHV
DQGFDXGDOÀQ
160 J.G. LUNDBERG,C.COX FERNANDES,R.CAMPOS-DA-PAZ & J.P. SULLIVAN
m off convex beach with grass and cecropia, 3°49’06.5”S,
·µ: -XO )LHOGQR$0==DQDWD
HWDO8) PP 7/ PDOHULR6ROLP}HV EH-
low rio Purus, collected with 3 m bottom trawl in channel,
40-60 m off linear beach with grass and shrub, 3°36’01.4”S,
··¶:-XO)LHOGQR0737ROHGR
Piza et al. ANSP 193098, 1, 100 mm TL, electric organ dis-
FKDUJHYRXFKHU QR -3)ULR 3XUXV DERYH6ROLP}HV
collected with 3 m bottom trawl in channel 12-13 m deep,
250-300 m off shore, 3°43’28.3”S, 61°27’12.8”W, 25 OCT
)LHOG QR -3)-)ULHO HW DO&$6
PP 7/ IHPDOH ULR 3XUXV DERYH ULR 6ROLP}HV FRO-
lected with 3 m bottom trawl in channel, 30-23.9 m deep, 300
PRIIFRQFDYHEDQNZLWKIRUHVW·µ6·µ:
-XO)LHOGQR$0==DQDWDHWDO5LR-DSXUi
DUHD8610PP7/ULR6ROLP}HVEHORZULR
-DSXUiFROOHFWHGZLWKPERWWRPWUDZOLQFKDQQHOP
deep, 25 m off linear sandy beach with grass, 3°18’46.3”S,
·µ:2FW)LHOGQR6/--HZHWWHW
DO8610PP7/ULR-DSXUiDERYHULR6R-
OLP}HVFROOHFWHGZLWKP ERWWRPWUDZOLQFKDQQHO P
GHHSP RIIOLQHDUPXGG\EDQNZLWKJUDVV·µ6
·µ: 1RY )LHOG QR 6/- -HZHWW
et al. ANSP 189210, 1, 100 mm TL, tissue voucher, rio So-
OLP}HVDERYH ULR-DSXUi FROOHFWHGZLWK PERWWRPWUDZOLQ
channel, 8.5-17 m deep, 3°14’10.0”S, 64°46’08.8”W, 31 Oct
)LHOGQR-3))ULHOHWDO5LR-XUXiDUHD,13$
PP 7/ RQH LV IHPDOH ULR -XUXi DERYH
ULR 6ROLP}HV FROOHFWHG ZLWK P ERWWRP WUDZO LQ FKDQQHO
11.2-6.5 m deep, 60-70 m off concave shore, 2°39’24.1”S,
·µ: 1RY )LHOG QR -3) )ULHO HW
al. ANSP 193099, 1, 179 mm TL, electric organ discharge
DQGWLVVXHYRXFKHUQR272ULR-XUXiDERYH6ROLP}HV
collected with 3 m bottom trawl in channel 9-10 m deep,
·µ6·µ: 129 )LHOG QR 272
2 2\DNDZD HW DO$163 PP 7/
HOHFWULFRUJDQ GLVFKDUJHYRXFKHU QR-*/ULR -XUXi
DERYH6ROLP}HVFROOHFWHGZLWKPERWWRPWUDZOLQFKDQQHO
PGHHS·µ6·µ:129)LHOG
QR-*//XQGEHUJHWDO5LR,oDDUHD&8
PP7/ULR,oDDERYHULR6ROLP}HVFROOHFWHGZLWK
3 m bottom trawl in channel, 17.8-14.6 m deep, ca 120 m off
OLQHDUEDQNZLWKIRUHVW·µ6·µ:1RY
)LHOG QR-366XOOLYDQHWDO/$&0
PP7/ ULR6ROLP}HVDERYHULR,oD &RO-
lected with 3 m bottom trawl in channel, 3.2-2.1 m deep, 10
PRIIVKRUH ·µ6·µ:1RY )LHOG
QR-3))ULHO HW DO3(58/RUHWR 'HSDUWPHQW 5tR
Amazonas - ANSP 182576, 4, 86.78-146.3 mm TL, PERU,
'HSW/RUHWR 3URY0D\QDVUtR$PD]RQDV YLFLQLW\RI ,TXL-
WRV·µ6·µ:$XJ)LHOGQR3(58
05-07, Sabaj et al.
)LHOGQR )//DQJHDQLHW DO)01+
1, 96.19 mm TL, rio Amazonas below rio Madeira, collect-
ed with 3 m bottom trawl in channel, 200 m off shore with
forest and grass, 3°19’59.7’‘S, 58°35’43.9’‘W, 9 Aug 1996,
&&)&R[)HUQDQGHVHWDO,13$PP
TL, female, rio Madeira above rio Amazonas, collected with
the holotype by a 3 m bottom trawl in channel, 16.1-13.9 m
GHHSPRIIOLQHDUEHDFKDQGEDQNZLWKIRUHVWDQGJUDVV
··¶6··¶:$XJ )LHOGQR $0=
96-139. Zanata et al. MZUSP 111955, 1, 96.5 mm TL, rio
Madeira aboverio Amazonas, collected with 3 m bottom trawl
in channel, 15-11.7 m deep, 800 m off concave shore with
forest, grass and shrub, 3°30’13.9’‘S, 58°52’54.4’‘W, 5 Aug
)LHOG QR &&) &R[)HUQDQGHV HW DO )01+
121336, 1, 100.5 mm TL, rio Madeira above rio Amazonas,
collected with 3 m bottom trawl in channel, 16.7-13.9 m
GHHS PRIIFRQFDYHEHDFKDQG EDQNZLWK IRUHVWJUDVV
DQGVKUXE··¶6 ··¶:$XJ)LHOG
no. MTP-96-121, Toledo-Piza et al. Rio Negro area - INPA
PP7/ULR 1HJURDERYHULR 6ROLP}HV$P-
azonas, collected with 3 m bottom trawl in channel, 30-21.5
PGHHS FDPRIIFRQFDYH EHDFKDQG EDQNZLWKIRUHVW
··¶6··¶:-XO )LHOG QR$0=
96-005, Zanata et al. ANSP 408388, 2, 82.5-113 mm TL, rio
1HJUR DERYH ULRV 6ROLP}HV$PD]RQDV FROOHFWHG ZLWK P
bottom trawl in channel, 27.2-24.5 m deep, 750 m off convex
VDQGDQG PXGEHDFKDQGEDQN·µ6·µ:
'HF )LHOGQR -*/ /XQGEHUJHW DO$163
199192, 3, 113-140 mm TL, rio Negro below rio Branco, col-
lected with 3 m bottom trawl in channel, 20.0-11.5 m deep,
ca. 200 m offshore, 1°59’00.5”S, 61°14’57.2”W, 4 Dec 1993,
)LHOGQR -*//XQGEHUJHWDO$163 DOF
93-102 mm TL, 1 C/S (formerly UAZ 95-160), 112 mm TL,
ULR6ROLP}HVDERYHULR1HJURFROOHFWHGZLWKPERWWRPWUDZO
in channel 39-50 m deep, 3°13’30.2”S, 59°53’41.9”W, 24 Oct
)LHOGQR-3))ULHOHWDO$163
7/HOHFWULFRUJDQGLVFKDUJHDQGWLVVXHYRXFKHUQR-*/
ULR1HJUR DERYH6ROLP}HV$PD]RQDVFROOHFWHGZLWK
m bottom trawl in channel 24-25 m deep, 300 m off linear
EHDFK·µ6·µ:'(&)LHOGQR
-*//XQGEHUJHW DO$01+ PP
7/PDOHULR6ROLP}HVDERYHULR1HJUR FROOHFWHGZLWKP
ERWWRPWUDZOLQFKDQQHOPRIIOLQHDUEHDFKDQGEDQNZLWK
grass, shrub and aquatic plants, 3°13’22.8’‘S, 59°55’24.0’‘W,
-XO )LHOG QR &&) &R[)HUQDQGHV HW DO
ANSP 199193, 1, 130.2 mm TL, male, rio Amazonas be-
low rio Negro, collected with 3 m bottom trawl in channel,
FDPRII OLQHDU WRFRQFDYHEDQN ZLWK JUDVV DQG DTXDWLF
SODQWV··¶6··¶: -XO)LHOG QR
AMZ-96-048, Zanata et al. Rio Purus area - ANSP 199194,
PP7/VPDOOHULVIHPDOHULR6ROLP}HVDERYH
rio Purus, collected with 3 m bottom trawl in channel, 70
NEW STERNARCHELLA KNIFEFISH 161
)LJ /DWHUDO YLHZ RI Sternarchella calhamazon Paratypes. A. ANSP 182576, fresh specimen collected near Iquitos, Peru, photo
courtesy of M. Sabaj Peréz. B. ANSP 193096, cleared and stained specimen (112 mm TL) showing enlarged anterior displaced hemal
VSLQH'+6HDQGRQHVPDOOGLVSODFHG KHPDOVSLQH'+6V GRUVDOÀODPHQWVHSDUDWHGIURPGRUVXPVKRUWDQG GHHSFDXGDOSHGXQFOH
ORQJKHPDOVSLQHV+6RIWKHPLGGOHFDXGDOYHUWHEUDHUHODWLYHWRDQDOÀQSUR[LPDOUDGLDOV35DQGGHHSHOHFWULFRUJDQFURVVHGE\WZR
URZVRILQWHUPXVFXODUERQHVP\EYYHQWUDOP\RUKDEGRLIEYYHQWUDOVHULHVRIÀODPHQWRXVERQHVDQGFDXGDOÀQ
)LJ0DSRIFROOHFWLRQORFDOLWLHVUHFRUGHGLQ WKLVZRUNIRUSternarchella calhamazon, some single spots include multiple proximate
samples and star indicates type locality in lower rio Madeira. Base map of drainages and elevations provided by Conservation Science
3URJUDP:RUOG:LOGOLIH)XQG86LQVHWNH\VVKDGLQJRIHOHYDWLRQVEHORZPZKHUHWKHVSHFLHVPRVWO\RFFXUV
162 J.G. LUNDBERG,C.COX FERNANDES,R.CAMPOS-DA-PAZ & J.P. SULLIVAN
)LJ$ERYH%LSORWVVKRZLQJYDULDWLRQLQWDLOVKDSHDPRQJVSHFLHV of Sternarchella. Upper biplot. Caudal peduncle depth at end of
DQDOÀQYV/($/RZHUELSORW&DXGDOSHGXQFOHGHSWKDWHQGRIDQDOÀQYVFDXGDOSHGXQFOHOHQJWK.
)LJ 3DJH /DWHUDO YLHZVRI$Sternarchella orthos$163 UtR 2ULQRFR%Sternarchella schotti$163UtR
Amazon, C. Sternarchella terminalis ANSP 199196, rio Amazon, D. Sternarchella sima ANSP 199200, rio Amazon, E. Sternarchella
orinoco ANSP, 149921, rio Orinoco.
NEW STERNARCHELLA KNIFEFISH 163
164 J.G. LUNDBERG,C.COX FERNANDES,R.CAMPOS-DA-PAZ & J.P. SULLIVAN
NEW STERNARCHELLA KNIFEFISH 165
Diagnosis.—Sternarchella calhamazon is distinguished
by its unique tail shape and associated anatomical features. 1)
&DXGDOSHGXQFOHDQGHOHFWULFRUJDQXQXVXDOO\GHHS)LJV
FDXGDOSHGXQFOHGHSWKDWHQGRIDQDOÀQFRQWDLQHG
12-18 times in LEA, 0.7-2.5 times in its length, and electric
RUJDQGHSWKDWHQGRIDQDOÀQDERXWHTXDOWRRUDOLWWOHJUHDW-
er than snout length. 2) Caudal peduncle abruptly tapering
EHIRUH FDXGDO ÀQ )LJV 1RWH 7KH DEUXSW WDLO VKDSH
LVDWÀUVW VXJJHVWLYH RIGDPDJHDQG UHJHQHUDWLRQ EXWPRVW
specimens have normal electric organs, scalation, caudal ver-
WHEUDHDQGÀQV+HPDOVSLQHVDERYHPLGGOHWKLUGRIDQDO
ÀQ HORQJDWHQHDUO\ WZLFH ORQJHU WKDQ DGMDFHQW SUR[LPDO
DQDOÀQUDGLDOV)LJV%7ZRURZVRILQWHUPXVFX-
lar bones visible along ventral and ventrolateral sides of
SRVWHULRUO\GHHSHQLQJHOHFWULFRUJDQ)LJV&%7KHVH
DUHWKHYHQWUDOPRVWÀODPHQWRXVERQHVHULHVDQGORZHUURZ
of split ventral myorhabdoi series (Hilton et al., 2007). 5)
Precaudal vertebrae 13-15 (modally 14) including four
vertebrae of the Weberian complex.
Other species of Sternarchella differ from S. calhamazon
as follows. 1) Caudal peduncle and electric organ shallow
)LJVFDXGDOSHGXQFOHGHSWKDWHQGRIDQDOÀQFRQWDLQHG
>20 times in LEA, and usually contained >2.5 times in its
length in undamaged specimens, and electric organ depth at
HQG RI DQDO ÀQ OHVV WKDQ FD RI VQRXW OHQJWK &DXGDO
SHGXQFOHWDSHULQJJUDGXDOO\LQXQGDPDJHGVSHFLPHQV)LJ
+HPDO VSLQHV DERYH PLGGOH WKLUG RI DQDO ÀQ VKRUW DERXW
HTXDOWROHQJWKRIDGMDFHQWSUR[LPDODQDOÀQUDGLDOV)LJ%
4) A single or no row of intermuscular bones visible along the
posteroventral part of electric organ. 5) Precaudal vertebrae
generally more than 14: S. orthos bimodally 14,15 (n = 8); S.
orinoco modally 16 (15-16, n = 7), S. sima modally 15 (14-
16, n = 5), S. terminalis modally 15 (15-16, n = 14), S. cf.
terminalis modally 15 (15-16, n = 5), S. schotti modally 17
(16-17, n = 15).
Remarks.—Three additional features are useful for
discriminating the Amazonian and Orinocoan species of
Sternarchella. 0RXWKSRVLWLRQDQGGRUVDO SURÀOHRIWKH
KHDG)LJV Sternarchella sima and S. orinoco
have a subterminal to inferior mouth (i.e., fully visible in
ventral view) below a broadly rounded snout and dorsal
SURÀOHSternarchella calhamazon, S. orthos,S. schotti and
S. terminalis have a supraterminal or, in cases, terminal
mouth, above a slightly projecting chin and below an
anteriorly convex snout, and scarcely convex, straight
VOLJKWO\ FRQFDYH KHDG SURÀOH +RZHYHU ZH ÀQG VHYHUDO
VSHFLPHQV ZLWK PRUH GHHSO\ FRQFDYH KHDG SURÀOHV )LJ
8B-E) that are otherwise most similar to S. terminalis
)LJ$2I WKHVH WKHVSHFLPHQ LOOXVWUDWHG LQ)LJ(
may have some distortion of head shape related to ventral
K\SHUH[WHQVLRQ RI LWV K\RLG EDU EXW WKRVH LQ )LJV %'
DUHQRWXQXVXDOO\SUHVHUYHG:HÀQGERWKPDOHDQGIHPDOH
VSHFLPHQV ZLWK D FRQFDYH KHDG SURÀOH 7KH FRQFDYH
headed S. cf. terminalis also recall Magosternarchus
duccis )LJ ) ZKLFK KDV D FRQFDYH KHDG SURÀOH
upturned mouth and snout, and extremely jutting chin,
EXW WKHVH ÀVK GLIIHU WUHQFKDQWO\ LQ GHQWLWLRQ DQG RWKHU
diagnostic characters of Magosternarchus. With available
)LJ $ERYH /DWHUDO YLHZ ;UD\ LPDJHV RI PLGVHFWLRQ RI WDLO
DQG DQDO ÀQ VKRZLQJ KHPDO VSLQH +6 OHQJWK UHODWLYH WR DQDO
ÀQSUR[LPDOUDGLDOV35$Sternarchella calhamazon holotype,
INPA 37898, B. Sternarchella orthos, ANSP 165218.
)LJ 3DJH /DWHUDO YLHZ ;UD\ LPDJHV RI DQWHULRU ERG\
to anterior caudal vertebrae, showing enlarged displaced hemal
spine, DHS(e) and small displaced hemal spines, DHS(s).
A, B. Sternarchella calhamazon holotype, INPA 37898, C,
D. Sternarchella orthos $163 UtR 2ULQRFR ( )
Sternarchella schotti$163UtR$PD]RQ
166 J.G. LUNDBERG,C.COX FERNANDES,R.CAMPOS-DA-PAZ & J.P. SULLIVAN
spine. Sternarchella schotti)LJ &KDV RUPXFK H[-
panded, unevenly curved hemal spines below the two (or
one) centra posterior to the enlarged anterior displaced pos-
terior hemal spine. A cleared and stained specimen of S.
schotti (MZUSP 6558) reveals that these additional expand-
ed hemal spines are displaced to the right, adjacent to the
information we are uncertain if the concave-headed
specimens are taxonomically distinct from S. terminalis.
$QWHULRU KHPDO VSLQHV )LJV % Sternarchella
calhamazon, S. orthos, S. sima, S. orinoco and S. terminalis
have 1 or 2 small, thin displaced hemal spines below the
centrum posterior to the enlarged anterior displaced hemal
)LJ/DWHUDO YLHZVVKRZLQJPRXWK SRVLWLRQV DQGGRUVDO SURÀOHV RIKHDGV RI$ Sternarchella terminalisIURP $163 UtR
Amazon, B-E. S. cf. terminalis´FRQFDYHPRUSKVµDOVRIURP$163)Magosternarchus duccis$163UtR$PD]RQ
NEW STERNARCHELLA KNIFEFISH 167
Radiographs of preserved specimens of Sternarchella with
ÁXLGÀOOHGJDVEODGGHUVGRQRWUHYHDOWKHVL]HDQGVKDSHRI
that organ which requires dissection to examine.
Description³/DWHUDOYLHZVLQ)LJVDQGLOOXVWUDWH
ERG\DQGKHDGVKDSHDQGIRUPDQGSRVLWLRQRIÀQV7DEOH
1 summarizes morphometric descriptors of external form.
A small-bodied species, largest specimen in type series
185 mm TL and 169 mm LEA. Body strongly compressed,
elongate but caudal peduncle deep, steeply tapered near
end, short, its length in undamaged specimens contained
6-17 times in LEA, 3-9 times in LOD. Greatest body depth
EHKLQG RULJLQ RI DQDO ÀQ WKURXJK DEGRPHQ FRQWDLQHG
times in TL, 6-7 times in LEA, 3.5-5 times in LOD.
enlarged posterior gas bladder chamber (RCP, pers. obs.). A
VRPHZKDWVLPLODUFRQGLWLRQ RI WKHKHPDO VSLQHV LVÀJXUHG
E\$OEHUWDQG)LQNÀJLQWKHLUGHVFULSWLRQRI
WKHPRGLÀHGSRVWHULRUJDVEODGGHUFKDPEHULQSternopygus
macrurus Bloch and Schneider (Sternopygidae).
*DV EODGGHU )LJ Sternarchella schotti alone
has a much enlarged posterior expansion of the gas bladder
tapering into the tail region near the anterior hemal spines
)LJ$7KHRWKHUVSHFLHVRISternarchella have a small,
digitiform gas bladder that is less than half the length of the
DEGRPLQDOFDYLW\)LJ%:HQRWHWKDWWKHH[SDQGHGJDV
bladder of S. schottiLVUHDGLO\VHHQZLWKEDFNLOOXPLQDWLRQ
through the body wall in live and fresh specimens, and
in preserved specimens less than about 150 mm TL.
Table 1. Measurement data for holotype and some paratypes of Sternarchella calhamzon in mm or thousandths of standard dimensions.
$EEUHYLDWLRQV/($²OHQJWKWRHQGRIDQDOÀQ/2'²OHQJWKWRRULJLQRIGRUVDOÀODPHQW6/²VWDQGDUGOHQJWK7/²WRWDOOHQJWK
Character Holotype Range Mean N
TL in mm 162.8 82.5 - 185.4 125.3 36
SL in mm 157 79.1 - 180 120.2 35
LEA in mm 143.1 69.1 - 169.1 109.1 36
LOD in mm 54.6 28.6 - 67 43.3 36
LOD/LEA 381 343 - 467 398 36
LengthDQDOÀQEDVH/2' 2238 1789 - 2421 2103 36
Length caudal-peduncle/LOD 307 114 - 386 263 35
Length caudal-peduncle/LEA 117 45 - 159 105 35
/HQJWKWRRULJLQRIDQDOÀQ/2' 524 340 - 631 506 36
/HQJWKWRRULJLQRIDQDOÀQ/($ 200 147 - 244 200 36
Length to anus and urogenital papilla/LOD 285 120 - 408 291 36
Head length to gill membrane/LOD 532 370 - 568 478 36
Head length to gill membrane/LEA 203 162 - 209 189 36
Head length to bony opercle end/LOD 439 355 - 524 432 36
Head length to bony opercle end/LEA 167 155 - 186 171 36
(\HWRSHFWRUDOÀQRULJLQ/2' 374 246 - 441 330 36
'HSWKDWRULJLQRIGRUVDOÀODPHQW/2' 441 299 - 515 396 36
Maximum body depth/LOD 452 311 - 531 414 36
Head depth at occiput/LOD 401 276 - 453 371 36
Snout length/Head length to bony opercle end 285 276 - 366 302 36
Length from eye to chin tip/Head length to bony opercle end 305 287 - 390 332 36
Eye diameter/Snout length 56 48 - 97 69 36
Eye to anterior naris/Snout length 218 180 - 254 216 36
Interorbital distance/Snout length 98 142 - 236 194 36
168 J.G. LUNDBERG,C.COX FERNANDES,R.CAMPOS-DA-PAZ & J.P. SULLIVAN
'RUVDO SURÀOH ULVLQJ LQ D GHFUHDVLQJO\ FRQYH[ DUF
from snout tip to occiput, then nearly straight or slightly
FRQYH[WR EDVHRIFDXGDOÀQ9HQWUDOSURÀOHFRPPHQFLQJ
from slightly projecting chin, gently convex, descending
at about 45o to below opercle, more shallowly sloping
to abdomen, then straight or slightly convex across tail.
2ULJLQ RI GRUVDO ÀODPHQW EHIRUH D YHUWLFDO WKRXJK ÀUVW
WKLUG RI DQDOÀQ EDVH DQG RYHU th or 7th caudal vertebra,
GRUVDOÀODPHQWORQJUHDFKLQJRQWRFDXGDOSHGXQFOH/2'
contained 2-3 times in TL, 2-3 times in LEA. Origin of
DQDOÀQEHORZEDVHRISHFWRUDOÀQOHQJWKWRRULJLQRIDQDO
ÀQFRQWDLQHGWLPHVLQ7/WLPHVLQ/($WLPHV
LQ /2' /($FRQWDLQHG WLPHV LQ 7/ &DXGDO ÀQ
bluntly pointed, small, its length less than snout length,
FDXGDOÀQ UD\V PRGDOO\ 1 3UHFDXGDO
vertebrae 13-15 (N = 14), caudal vertebrae to end of anal
ÀQ1 WRWDOYHUWHEUDHWRHQGRI DQDOÀQ
(N =8). Posteriormost one or two precaudal vertebrae just
DQWHULRUWRWKH ÀUVW FDXGDOYHUWHEUDLH WKDW ZLWKDODUJH
hemal spine and supporting the much enlarged, so-called
)LJ$'LVVHFWHGVSHFLPHQRISternarchella schotti, ANSP 199792, showing enlarged gas bladder (GB) extending beyond abdominal
cavity into tail. B. Cleared and stained specimen of Sternarchella orthos, ANSP 199205, showing the more general condition in
Sternarchella of a small gas bladder (GB) extending less than half the length of the abdominal cavity to level of 7th vertebra.
NEW STERNARCHELLA KNIFEFISH 169
displaced hemal spine) have much reduced or no ribs and
short, distally-broad or split parapophyses.
Lateral line canal high on sides at 5-6 scale rows below
GRUVDO ÀODPHQW FDQDO WHUPLQDWLQJ RQ FDXGDO SHGXQFOH
6FDOHVODFNLQJ RQKHDGGRUVXPDQWHULRUWR FDXGDOHQG RI
GRUVDO ÀODPHQW DQG VLGHV GRUVDO WR SHFWRUDO ÀQ &\FORLG
VFDOHVHQODUJHGRQPLGGOHRIÁDQNVLQFOXGLQJSRUHGODWHUDO
OLQHVFDOHURZ6PDOOHU VFDOHV RQEUHDVWDQG ORZHUÁDQNV
RYHUDQDOÀQPXVFXODWXUH
Head compressed, deeply ovoid in cross section,
smooth and scaleless. HL contained 5-7 times in LEA and
2-3 times in LOD. Head depth at nape contained 6-8 times
in LEA and 1-1.3 times in HL. Snout length contained
3-4 times in HL. Chin slightly projecting. Mouth a little
superior, closed lips meet at a horizontal through middle
or lower half of eye. Mouth small, gape opening anteriorly
and not deeply cleft, maxilla nearly vertical, elongate
and strongly curved, rictus in advance of a vertical at
DQWHULRU QRVWULO -DZ WHHWK VWURQJ EXW VOHQGHU FRQLFDO
with inwardly curved tips, 3-4 symphyseal-tooth rows on
premaxilla and dentary. Lips smooth; a short rictal fold
curving dorsally around end of maxilla. Anterior nostril
behind upper lip on dorsolateral surface of snout, with a
VKRUW ÁHVK\ WXEXODU ULP $QWHULRU DQG SRVWHULRU QRVWULOV
separated by a distance nearly twice that between eye and
posterior nostril. Posterior nostril teardrop shaped, without
D UDLVHG ÁHVK\ ULP (\H VPDOO VXEFXWDQHRXV FHQWHUHG
GRUVRODWHUDOO\ZHOO DERYHPLGKRUL]RQWDOOLQHDQGRQ ÀUVW
third of head length; eye diameter contained 12-22 times in
HL to gill membrane, 3-7 times in snout length, 2-4 times
in interorbital width.
Gill opening restricted as an anteroventrally oblique
VOLW EHIRUH DQG DERYH SHFWRUDOÀQ EDVH *LOO PHPEUDQHV
XQLWHGDQGÁXVK ZLWKEUHDVW DQWHURYHQWUDO WRSHFWRUDO ÀQ
*LOO UDNHUV ZLWK GHQVH ÀEHURXV FRYHULQJ RU RQ ÀUVW
gill arch.
$QDOÀQHORQJDWHDQGZLWKVOLJKWO\FRQYH[PDUJLQLWV
ORQJHVWUD\VLQPLGGOHRIÀQDQDOÀQEDVHOHQJWKFRQWDLQHG
WLPHVLQ/($DQDOÀQUD\V1
DQWHULRU XQEUDQFKHG DQDOÀQ UD\V PRGDOO\ 1
3HFWRUDOÀQRULJLQ YHQWURODWHUDO RQ VLGHVLPPHGLDWHO\
behind gill opening; leading pectoral rays longest, margin
VFDUFHO\FRQYH[SHFWRUDOÀQOHQJWKDERXWHTXDOWRSRVWRU-
ELWDOKHDG OHQJWKWRWDO SHFWRUDOÀQUD\V ELPRGDOO\
1 OHDGLQJWZRSHFWRUDOÀQUD\VXQEUDQFKHG
Urogenital papilla and anus adjacent in both sexes
without visible sexual dimorphism, and positioned far in
DGYDQFHRIDQDOÀQRULJLQEHORZSRVWRUELWDOUHJLRQRIKHDG
between edges of united gill membranes.
&RORUDWLRQ *HQHUDOO\ D SDOOLG VSHFLHV ODFNLQJ EROG
SLJPHQWHG DUHDV IUHVK VSHFLPHQV SLQNLVK ZKLWH )LJ
those in preservative cream white, yellowish to tan. In
PRVWVSHFLPHQVGRUVXPRIKHDGEDFNDQGXSSHUPRVWVLGHV
peppered with scattered, small chromatophores densest on
PLGOLQH FKURPDWRSKRUHV RQ GRUVDO ÀODPHQW RIWHQ ODUJHU
WKDQRWKHUV(\HVGDUN2YHUDOOFOHDUWREOXLVKWUDQVOXFHQFH
ZKHUHWKLQHVSHFLDOO\GRUVDOÀODPHQWHOHFWULFRUJDQDQGDOO
ÀQPHPEUDQHV(OHFWULFRUJDQYLVLEOHZLWKWUDQVPLWWHGOLJKW
as far anterior as close behind abdominal cavity, deepening
posteriorly, imparting a transparency to most of tail.
Electric organ discharges (EODs) of three S.
calhamazon specimens (ANSP 193098, 193099, 193100)
IURP WKH ZKLWHZDWHU WULEXWDULHV 3XUXV DQG -XUXi DUH
YHU\VLPLODU WRHDFKRWKHU )LJ$&7KH\FRQVLVWRI
triphasic (positive, negative, positive) pulses, each of about
PLOOLVHFRQGVVHSDUDWHGE\D ÁDWEDVHOLQHRI DERXW
)LJ(OHFWULF RUJDQGLVFKDUJH(2' ZDYHIRUP RVFLOORVFRSH
traces, each of 5 millisecond duration, for A-D. Sternarchella
calhamazon (A. ANSP 193100, B. ANSP 193099, C. ANSP
' $163 () Sternarchella terminalis (E.
$163 ) * Magosternarchus raptor ANSP
192745, H. Magosternarchus duccis ANSP 192638. Head
positivity upwards. See text for discussion.
170 J.G. LUNDBERG,C.COX FERNANDES,R.CAMPOS-DA-PAZ & J.P. SULLIVAN
milliseconds. The repetition rate is between 772 and 826
+])RU RQHVSHFLPHQ$163IURPWKH ORZHUULR
Negro near the Anavilhanas Archipelago, the EOD has a
similar repetition rate (966 Hz), but the EOD is biphasic,
with “shoulders” on the rising and falling phases.
Distribution and habitat.—Sternarchella calhamazon
is wideranging and common in the large river channels (from
aPGHHSRIWKH$PD]RQ6ROLP}HVPDLQVWHPDQGPDMRU
tributaries from the Pará and Tocantins to Iquitos, and upstream
LQULR1HJURWRDWOHDVWWKHFRQÁXHQFHRIULR%UDQFRDQGLQWKH
ULR0DGHLUDWR DWOHDVWWKH FRQÁXHQFHZLWKUtR %HQL)LJ
This species is expected to occur throughout the lowland rivers
RIWKH$PD]RQ EDVLQ)URP RXUWUDZO FROOHFWLRQVLQ WKHPDLQ
channel of the Amazon river and tributaries, S. calhamazon was
the most abundant gymnotiform species present in 12 of the
13 tributaries sampled, with the Coari being the exception. Its
highest numbers (100s to just >1000) were in the mainstream
RI WKH $PD]RQ VXFK DV EHORZ ULRV -DSXUi DQG 3XUXV DQG
also in tributaries of white Andean waters, such as rios Purus,
0DQDFDSXUXDQG0DGHLUD&R[)HUQDQGHV:LWK
a total catch of just over 5,000 individuals, Sternarchella
calhamazon was about four times more abundant than S.
terminalis, which was also abundant and present in almost
all of our sampling sites. The other three species, S. schotti,
S. sima and S. concave, exhibited 1/50th of the abundance of
S. calhamazon. We are not aware of specimens collected from
YDU]HDODNHVRUVPDOOPDUJLQDOVWUHDPV
Etymology.—The name calhamazon (phonetic
pronounciation CAL-YAH-MAZON) is from the
Portuguese calha for channel plus Amazon, and is the
name given to the 1992-1997 Brazilian-US collaborative
ichthyological inventory of the deep river channels of the
Brazilian Amazon.
DISCUSSION
Albert (2001: 77) proposed two monophyletic
sister-groups within Sternarchella. The “Sternarchella
schotti species-group” (S. orthos,S. schotti,S. terminalis)
recognized on the basis of a “terminal or slightly superior
PRXWK DV DGXOWVµ )LJV $& $OEHUW·V ´Sternarchella
sima species-group” (S. sima>)LJV'@S. curvioperculata
(but see below), “Sternarchella sp. S”, and S. orinoco
IROORZLQJ,YDQ\LVNL>@LVFKDUDFWHUL]HGE\D´YHQWUDO
mouth, a strongly rounded forehead, and large scales, 5-8
above lateral line” (Albert, 2001:77).
%DVHGRQLWVVXSHULRUPRXWK)LJVS. calhamazon
falls into the S. schottiVSHFLHVJURXS7KHIRUHKHDGSURÀOH
of S. calhmazon OLNH WKH RWKHU VSHFLHV LQ WKH S. schotti
VSHFLHVJURXSLVGRUVDOO\FRQYH[ )LJV $&QRW
“strongly rounded” as noted for the “Sternarchella sima
VSHFLHVJURXSµ)LJV'
Scale size and number, on the other hand, do not
provide informative taxonomic discrimination or phyloge-
netic support for either species group of Sternarchella. As
indicated, species of the S. sima species-group have 5-8
ODUJH VFDOHV DERYH ODWHUDO OLQH DQG ZH ÀQG VLPLODUO\
large scales in S. calhamazon, 5-6 in S. orthos (see Mago-
Leccia, 1994:85), 6-9 in S. schotti, and 7-9 in S. termina-
lis1RWDEO\KRZHYHURQHRIXV5&3ÀQGVSternarchella
curvioperculata to have 13-14 small scales above lateral
line. Preliminary analysis suggests that this species does
not belong in Sternarchella as delimited herein (to be dis-
cussed elsewhere by RCP). A revision of Sternarchella by
6 ,YDQ\LVN\ LQ - $OEHUW·V ODE SURPLVHV WR VROYH
these and other questions that fall beyond the scope of the
present contribution.
7KHWULSKDVLFZDYHIRUP(2'V)LJ$&RIWKUHH
S. calhamazon specimens from the white water Purus and
-XUXiULYHUVDUHFORVHO\VLPLODUWRRQHDQRWKHUDQGUHVHPEOH
the EODs reported by Turner et al. (2007) for S. terminalis,
and species of Apteronotus and Sternarchorhynchus.
Most of our EOD records for S. terminalis and all
Magosternarchus )LJ (+ DOVR H[KLELW VLPLODU
triphasic EODs, however the repetition rates for these
species are much faster, i.e. S. calhamazon 772-966 Hz
(mean = 836 Hz, n = 4) vs. S. terminalis 1304-1781 Hz
(mean = 1572 Hz, n = 8) Magosternarchus raptor 1765-
2111 Hz (mean = 1938 Hz, n = 2) and M. duccis 1721-2260
Hz (mean = 1971 Hz, n = 3) between 1400 and 1800 Hz
)LJ(+2XUVLQJOHS. calhamazon specimen from rio
1HJURKDVDQ(2'UHFRUGLQJ)LJ'WKDWLVGLVWLQFWO\
ELSKDVLF7KLV ÀVK LVVPDOO DW PP7/DQGSHUKDSV D
juvenile with an immature waveform. However, the still
smaller Purus specimen (100 mm TL) of S. calhamazon
produced a triphasic EOD. Larger EOD sample sizes
will be needed to search for correlations between EOD
waveforms and variations in age, sex, breeding condition,
habitat or cryptic taxonomic diversity.
Sternarchus capanemae³,Q -XO\ DW D
PHHWLQJ RI WKH $NDGHPLH GHU :LVVHQVFKDIWHQ 9LHQQD
Austria), Steindachner presented a note on the
J\PQRWLIRUP ÀVKHV LH KLV ´*\PQRWLGDHµ LQ WKH ´N
N +RI1DWXUDOLHQFDELQHWHV ]X :LHQµ 7KDW FRQWULEXWLRQ
subsequently published in the “Anzeiger der Kaiserlichen
$NDGHPLH GHU :LVVHQVFKDIWHQµ 6WHLQGDFKQHU D
introduced three previously undescribed species placed
in the nominal genus Sternarchus:S. nattereri (=
Sternarchogiton nattereri), S. capanemae (= Sternarchella
capanemae) and S. mormyrus (= Sternarchorhynchus
mormyrus). Each species’s name, in that paper, was
followed by a succinct diagnosis. Concerning Sternarchus
NEW STERNARCHELLA KNIFEFISH 171
capanemae, its brief diagnosis was based on a single
specimen from the mouth of rio Negro, near Manaus,
Brazil, and mentioned only the somewhat straight dorsal
KHDGSURÀOHZKHQFRPSDUHGWRS. nattereri), and the short
snout and gape in contrast to Sternarchorhynchus mormyrus
(Steindachner, 1868a:176). No additional information was
provided in that paper concerning S. capanemae. In fact,
that was the only place Steindachner ever mentioned that
WD[RQRPLFQDPH$FFRUGLQJ WR% +HU]LJDQG (0LNVFKL
(Naturhistorisches Museum, Vienna; pers. communic. to
RCP), no specimen is labeled as “Sternarchus capanemae”
LQWKHÀVKFROOHFWLRQVDWWKH10:6LQFHLWVRULJLQLQ
the name Sternarchus capanemae appeared only once in
the literature, being cited by Albert (2001:126) as a junior
synonym of Sternarchella schotti. No explanation of the
WD[RQRPLFVWDWXVRIWKHQDPHZDVSURYLGHGLQWKDWZRUN
/DWHU6WHLQGDFKQHU ESXEOLVKHGDQRWKHU ZRUN
RQ J\PQRWLIRUP ÀVKHV &XULRXVO\ S. nattereri and S.
mormyrus were again objectively and explicitly indicated as
“new species” within Sternarchus. Their names, however,
were this time associated with more detailed descriptions.
Sternarchus capanemae, however, was not listed by
name in Steindachner’s second paper. Instead, another
new binomen appears to replace S. capanemae, namely,
Sternarchus schotti (between Sternarchus nattereri and
Sternarchus mormyrus; see Steindachner, 1868b:252). The
description of Sternarchus schotti, explicitly based on a
VLQJOHVSHFLPHQÀJXUHGLQ6WHLQGDFKQHUWDEV
conforms well with the shorter one given for S. capanemae
(Steindachner, 1868a). The holotype of Sternarchus schotti
ZDV UHSRUWHGO\ FROOHFWHG E\ - 1DWWHUHU DW ´%DUUD GR ULR
Negro” (mouth of the rio Negro, near Manaus, Brazil) is
currently housed at the NMW (NMW 65335).
According to B. Herzig (pers. comm. to RCP), it
was a common procedure among Viennese naturalists in
6WHLQGDFKQHU·V GD\V WR TXLFNO\ SXEOLVK D VKRUW DFFRXQW
for instance about new species, in the “Anzeiger der
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SUHVHQWD PRUHGHWDLOHG ZRUNODWHU LQDQRWKHU MRXUQDO7KDW
seems to be the case for the nominal Sternarchus capanemae
and Sternarchus schotti, meaning that they are objective
synonyms based on the same single specimen (International
Commission of Zoological Nomenclature [ICZN], Art.
61.3.4). In this case, Stiendachner created the later name to
KRQRU+:6FKRWW DERWDQLFDOFRPSDWULRWZKRXQGHUWRRN
expeditions to Brazil in the early 19th century.
$ÀQDOTXHVWLRQHPHUJHVIURPWKHIDFWWKDWSternarchus
capanemae was described earlier in 1868 than Sternarchus
schotti.Sternarchus capanemae should then be treated as
the senior synonym and S. schotti the junior synonym.
However, we note the following clear situations concerning
these names, both explicitly indicated in the current version
of the ICZN: 1) “the senior synonym . . . has not been used
as a valid name after 1899” (Art. 23.9.1.1); and 2) “the
junior synonym . . . has been used for a particular taxon, as
LWVSUHVXPHGYDOLGQDPHLQDWOHDVWZRUNVSXEOLVKHGE\
at least 10 authors in the immediately preceding 50 years
and encompassing a span of not less than 10 years” (Art.
23.9.1.2). Therefore, we recommend and we will apply to
the International Commission of Zoological Nomenclature
for conservation of the species name Sternarchella schotti
Steindacher (1868b). Effective communication about
HOHFWULFÀVKHVRIWKHJHQXVSternarchella is best served by
À[LQJWKHORQJVWDQGLQJXVHRIS. schotti and by rendering
the obsolete name Sternarchus capanemae Steindacher
(1868a) suppressed.
&203$5$7,9(0$7(5,$/(;$0,1('
Magosternarchus duccis, ANSP 173506, 1, 151 mm
7/UtR$PD]RQ
Sternarchella orthos: Venezuela. ANSP 199203, 3,
PP7/UtR2ULQRFR$163
PP7/UtR$SXUH$163 IRUPHUO\'8)
DOF&6PP7/UtR2ULQRFR$163
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Sternarchella orinoco9HQH]XHODUtR2ULQRFR$163
PP7/$163IRUPHUO\'8)
2024) 1 C/S. ANSP 199202, (formerly UAZ 95-154) 1
&6PP7/WDLOEURNHQ
Sternarchella schotti: Brazil. ANSP 199792, 2,
173-181 mm TL, rio Amazonas, Lago do Rei. ANSP
199195, 5, 147-179 mm TL, rio Amazonas above rio
Trombetas. MZUSP 6558, 1 C/S, 155 mm TL. Colombia.
)01+ PP7/$PD]RQ5LYHU3HUX
ANSP 84267, 1, 197 mm TL, Ucayali River Basin near
Cantamana.
Sternarchella sima: Brazil. ANSP 199200, 5, 105-142
mm TL, rio Pará below rio Amazonas.
Sternarchella terminalis: Brazil. ANSP 199196, 5,
109-182 mm TL, rio Amazonas above rio Tapajos. ANSP
199197, 3, 119-192 mm TL, rio Pará above rio Tocantins.
ANSP 199198 (formerly UAZ 95-163), 1 C/S, 160 mm
7/ULR6ROLP}HVEHORZULR,oD
Sternarchella cf. terminalis, ANSP 199199, 5, 178-
PP7/ULR$PD]RQDVEHORZULR;LQJX
ACKNOWLEDGEMENTS
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Leccia and Dr. E. Marsh-Matthews for our detailed and
LQIRUPDWLYH HDUO\ ZRUN RQ WKH WD[RQRP\ RI Sternarchella
DQGUHODWHGJ\PQRWLIRUPV)RUFDUHIXOHGLWRULDORYHUVLJKWZH
WKDQN06DEDM 3pUH]$163DQG(+LOWRQIRUDGGLWLRQDO
172 J.G. LUNDBERG,C.COX FERNANDES,R.CAMPOS-DA-PAZ & J.P. SULLIVAN
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systematics of Gymnotiformes with diagnoses of
58 clades: a review of available data. Pp. 419-446.
In: Malabarba, L.R., R.E. Reis, R.P. Vari, Z.M.S. de
Lucena and C.A.S. Lucena (eds) 1998 Phylogeny and
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Alegre. 1-603.
&DPSRVGD3D]5DQG-6$OEHUW7KHJ\PQRWLIRUP
´HHOVµRIWURSLFDO$PHULFDDKLVWRU\RI FODVVLÀFDWLRQ
and phylogeny of the South American Electric
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401-417. In: Malabarba, L.R., R.E. Reis, R.P. Vari,
Z.M.S. de Lucena and C.A.S. Lucena (eds) 1998
3K\ORJHQ\ DQG FODVVLÀFDWLRQ RI 1HRWURSLFDO ÀVKHV
Edipucrs, Porto Alegre. 1-603.
&R[ )HUQDQGHV & 'LYHUVLW\ GLVWULEXWLRQ DQG
FRPPXQLW\VWUXFWXUHRIHOHFWULFÀVKHV*\PQRWLIRUPHV
in the channels of the Amazon River System, Brazil.
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Durham, 394 pp.
&R[ )HUQDQGHV & 'HWUHQGHG FDQRQLFDO FRUUHVSRQG
HQFH DQDO\VLV '&&$ RI HOHFWULF ÀVK DVVHPEODJHV LQ
the Amazon. In:$9DODQG90)$OPHLGD9DOHGV
%LRORJ\RI7URSLFDO)LVKHV,13$0DQDXVSS
&R[ )HUQDQGHV & - 3RGRV -* /XQGEHUJ
Amazonian ecology: tributaries enhance the diversity
RIHOHFWULFÀVKHV6FLHQFH
&R[ )HUQDQGHV & -* /XQGEHUJ DQG -3 6XOOLYDQ
2009. Oedemognathus exodon and Sternarchogiton
nattereri (Apteronotidae, Gymnotiformes): the
FDVH IRU VH[XDO GLPRUSKLVP DQG FRQVSHFLÀFLW\
Proceedings of the Academy of Natural Sciences of
Philadelphia 158:193-207.
Eigenmann, C.H. and D.P. Ward. 1905. The Gymnotidae.
Proceedings of the Washington Academy of Science.
v. 7: 159-188, Pls. 7-11.
Ellis, M.M. 1913. The gymnotoid eels of Tropical America.
Memoirs of the Carnegie Museum 6(3):109-195.
,YDQ\LVNL 6- 6\VWHPDWLFV DQG ELRJHRJUDSK\ RI
Sternarchellini (Gymnotiformes: Apteronotidae):
GLYHUVLÀFDWLRQ RI HOHFWULF ÀVKHV LQ ODUJH$PD]RQLDQ
rivers. Unpublished MSc Dissertation. University of
Louisiana, Lafayette. 78 pp.
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and operation of a small trawling apparatus for use
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Management. 4 (3):331-334.
/XQGEHUJ -* C &R[ )HUQDQGHV -6 $OEHUW DQG 0
Garcia. 1996. Magosternarchus, a new genus with
WZR QHZ VSHFLHV RI HOHFWULF ÀVKHV *\PQRWLIRUPHV
Apteronotidae) from the Amazon River Basin, South
America. Copeia 1996(3):657-670.
corrections and constructive comments on the manuscript;
WKH DXWKRUV WDNH UHVSRQVLELOLW\ IRU LQWHUSUHWDWLRQV DQG UH-
PDLQLQJHUURUV)RUKLVNHHQWHFKQLFDODQGDUWLVWLFDVVLVWDQFH
ZHWKDQN. /XFNHQELOO $163 0 6DEDM3pUH]$163
generously provided a color photo of the fresh Peruvian
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the Calhamazon Project’s 1993, 1994 and 1996 expedi-
WLRQWHDPV- %DVNLQ - )ULHO0*DUFLD )/DQJHDQL 2
2\DNDZD/5DSS3\'DQLHO55HLV 07ROHGR3L]D0
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at MZUSP for laboratory space and collection access.
7KH 86 1DWLRQDO 6FLHQFH )RXQGDWLRQ VXSSRUWHG WKH
´&DOKDPD]RQ 3URMHFWµ WKURXJK D UHVHDUFK JUDQW WR -*/
(DEB- 9300151). Additional support for that project was
SURYLGHGE\WKH2IÀFHRI)RUHVWU\(QYLURQPHQWDQG1DWXUDO
Resources, Bureau of Science and Technology, of the U.S.
Agency for International Development and the Conselho
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(CNPq, Brazilian National Research Council). Permission to
FRQGXFWUHVHDUFKDQGFROOHFWLQ%UD]LOZDVJUDQWHGWR-*/E\
CNPq. Partial support for this research came from Instituto
Nacional de Pesquisas da Amazônia (INPA), Programa
5+$(,13$&13T DQG D 0HOORQ )RXQGDWLRQV *UDQW WR
WKH 'XNH 8QLYHUVLW\8QLYHUVLW\ RI 1RUWK &DUROLQD /DWLQ
$PHULFDQ6WXGLHV3URJUDPWR&&)IURPWRDQG
IURPWKH8QLYHUVLW\RI0DVVDFKXVHWWV$PKHUVW&&)·V
WUDYHO WR $163 ZDV VXSSRUWHG E\ 7KH %|KONH 0HPRULDO
)XQG $ 6KRUW7HUP 9LVLWRU *UDQW IURP WKH 6PLWKVRQLDQ
Institution, allowed RCP to travel to NMNH in 2001, to
study part of the Sternarchella under the sponsorship of R.P.
Vari. The “Calhamazon Project” partly supported RCP’s
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examine gymnotiforms including Sternarchella.
The Orinoco Delta Expeditions were supported by
861DWLRQDO6FLHQFH)RXQGDWLRQWKURXJKUHVHDUFKJUDQWV
'(%WR-*/DQG-1%DVNLQDQG'(%
WR-1%DQG-*/,QWKDWZRUN-*/DOVRDFNQRZOHGJHVXVH
RI59 (DVWZDUGRSHUDWHGE\'XNH8QLYHUVLW\ WKH'XNH
1DWLRQDO 2FHDQRJUDSKLF )DFLOLW\ LQ DQG ZDV
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LITERATURE CITED
$OEHUW -6 6SHFLHV GLYHUVLW\ DQG SK\ORJHQHWLF
V\VWHPDWLFVRI$PHULFDQ NQLIHÀVKHV*\PQRWLIRUPHV
Teleostei). Miscellaneous Publications, Museum of
Zoology, University of Michigan No. 190: i-vi + 1-127.
$OEHUW -6 DQG :/ )LQN Sternopygus xingu, a
QHZ VSHFLHV RI HOHFWULF ÀVK IURP %UD]LO 7HOHRVWHL
Gymnotoidei), with comments on the phylogenetic
position of Sternopygus”. Copeia 1996 (1):85-102.
NEW STERNARCHELLA KNIFEFISH 173
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6\VWHPDWLFV RI WKH 6RXWK $PHULFDQ ÀVK JHQXV
Adontosternarchus (Gymnotiformes, Apteronotidae).
Los Angeles County Museum of Natural History,
Contributions in Science, No. 359, 19 pp.
0DJR/HFFLD ) (OHFWULF ÀVKHV RI WKH FRQWLQHQWDO
ZDWHUV RI $PHULFD &DUDFDV )XQGDFLyQ SDUD HO
'HVDUUROOR GH ODV &LHQFLDV )LVLFDV 0DWHPDWLFDV \
1DWXUDOHV(OHFWULFÀVKHVRIWKHFRQWLQHQWDOZDWHUVRI
America: 1-206, 16 unnumbered tables.
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&KHFNOLVWRIWKHIUHVKZDWHUÀVKHVRI6RXWKDQG
&HQWUDO $PHULFD &/2))6&$ (',38&56 3RUWR
Alegre. 2003: i-xi + 1-729.
Sabaj Pérez, M.H. (ed.). 2012. Standard symbolic codes
for institutional resource collections in herpetology
and ichthyology: an online reference. Verson 3.0 (23
)HEUXDU\ (OHFWURQLFDOO\ DFFHVVLEOH DW KWWS
www.asih.org/, American Society of Ichthyologists
and Herpetologists, Washington, DC.
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Hof-Naturaliencabinetes zu Wien. Anzeiger der
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177.
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Naturaliencabinetes zu Wien. Sitzungsberichte der
Mathematisch-Naturwissenschaftlichen classe der
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264.
7XUQHU&50'HU\OR&'GH6DQWDQD-$$OYHV*RPHV
and G.T. Smith. 2007. Phylogenetic comparative
analysis of electric communication signals in ghost
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of Experimental Biology 210, 4104-4122.