Taxonomic assessment of Leptodoras (Siluriformes: Doradidae) with descriptions of three new species
Author
Sabaj, Mark Henry
text
Neotropical Ichthyology
2005
2005-12-31
3
4
637
678
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252005000400020&lng=en&tlng=en
journal article
10.1590/S1679-62252005000400020
1982-0224
5418130
FA5585FE-A7B5-41AC-AE22-17F2399A6FB5
Leptodoras linnelli
Eigenmann, 1912
Figs. 4e
,
5a
,
14
and
15a,b
Leptodoras linnelli
Eigenmann 1912:191
, pl. 17 (fig. 1), pl. 18 (fig. 1) (
type
locality:
Potaro river
(Essequibo dr.) at
Tumatumari
,
Mazaruni-Potaro
,
Guyana
).
Diagnosis
. Uniquely distinguished among
Leptodoras
by shape of upper labial extension: very elongate, straight to weakly curved medially, and nearly uniform in width with a bluntly rounded tip
vs
. moderately elongate and attenuate (in
L. praelongus
,
copei
,
hasemani
) or moderately to strongly curved and distal portion distinctly expanded with wide lateral flap (in
L. acipenserinus
,
nelsoni
,
rogersae
,
cataniai
,
juruensis
,
myersi
).
Leptodoras linnelli
is further distinguished from all
Leptodoras
except
L. acipenserinus
by having an adipose fin that extends anteriorly as a low thin ridge to a point midway between the anterior insertion of the adipose fin and the posterior insertion of the dorsal fin.
Leptodoras linnelli
is distinguished from
L. acipenserinus
by a number of characters including a relatively longer predorsal distance (35.5-38.7% SL
vs
. 31.6-35.6% in
acipenserinus
), inner flap of gill opening incomplete (
vs
. usually complete, nearly reaching cleithral notch in
acipenserinus
), lower sum of midlateral plates (74- 81
vs
.
77-86 in
acipenserinus
), anal-fin shape (tip of longest branched ray falls short of vertical through tip of last branched ray in extended anal fin and is more or less even with vertical through base of last ray; line defined by tips angled anteriorly, forming a 45-90° angle with long axis of body
vs
. tip of longest branched ray falls well short of base of last branched ray, line defined by tips sharply angled anteriorly, forming a 30-45° angle with long axis of body in
acipenserinus
), pectoral-fin spine length (19.9-26.2% of SL
vs
. 18.6-21.3% in
acipenserinus
) and pectoral-fin spine dentation (teeth strongly retrorse along majority of posterior margin, becoming less retrorse distally, size relatively uniform along distal half, last denticulation usually subterminal
vs
. teeth becoming gradually larger and less retrorse towards tip of spine, last and/or penultimate denticulation nearly perpendicular to long axis of spine, last denticulation terminal, its lateral margin continuous with tip of pectoral spine in
acipenserinus
).
Description
. Morphometrics summarized in
Table 1
. Similar in shape to
L. hasemani
except head very weakly depressed, snout comparatively longer and more acute; caudal peduncle moderately elongate, depressed. Eye large but with weakly developed adipose eyelid.
Mouth subterminal, jaws edentulous in adults and juveniles as small as
50 mm
SL. Maxillary barbel long, usually reaching ventromedial extent of gill opening. Secondary maxillary barbels 7-11 (modally 10), flattened, largely overlapping; proximal secondary maxillary barbels with fimbriate anterior margin and smooth posterior margin; distal ones smooth. Upper labial extension rather elongate, straight to weakly curved medially, width nearly uniform, tip bluntly rounded, ventral surface smooth, distal lateral margin weakly expanded and with small fimbriae. Lower labial extension narrow, attenuate, usually finishing even with or slightly beyond upper labial extension; margins smooth, distal tip often with few small papillae or fimbriae. Interlabial membrane of narrow to moderate width (labial extensions parallel or convergent), comparatively thin with few small papillae. Dorsolabial membrane weakly developed, evenly attenuate posteriorly. Two pairs of jaw barbels with scattered elongate papillae; cojoined by basal membrane; outer pair slightly longer than inner pair and shorter than maxillary barbel, cojoined with lower labial extension via narrow membrane. Branchiostegal membrane with moderately expanded fleshy margin overlapping ventral gill opening; fleshy inner flap along cleithrum incomplete, not reaching cleithral notch for pectoral spine insertion. First gill arch with 15-20 weakly developed gill rakers (length about 2-3 times width); accessory lamellae on medial face of arch and continue well onto medial face of gill filaments (present on every second or third filament); each accessory lamella appears as a column of lappets with first one (opposite rakers) enlarged and deflected medially; accessory lamellae absent or only very weakly developed on lateral faces of gill arch and filaments (may appear as one or few small lappets near base of filaments).
Fig. 14.
Leptodoras linnelli
, BMNH
1911.10.31:73-74 (SL 162.2 mm, paratype), Potaro river (Essequibo dr.) Tumatumari, Guyana.
Fig. 15.
Juvenile and subadult
Leptodoras
(Orinoco and Essequibo basins). a.
L. linnelli
, ANSP
175881 (SL 100.1 mm), Essequibo river, Guyana. b.
L. linnelli
, MBUCV-V 19689 (SL 100.5 mm), río Mavaca (Orinoco dr.), Amazonas, Venezuela. c.
L. rogersae
, paratype, MBUCV-V 13372 (SL 128.8 mm), río Orinoco, Delta Amacuro, Venezuela. d.
L. nelsoni
, paratype, MBUCV-
V 14769
(SL 104.5 mm), río Apure, Apure, Venezuela.
Sum of midlateral plates 74-81 (modally 76, Table 3).Anterior midlateral plates moderately deep, covering about half of corresponding body depth; posterior margins of dorsal and ventral wings rounded with many small serrae. Tympanum usually with 3 small ossifications (weak spines) along postotic laterosensory canal; small fixed spine usually visible along posterior margin of neurocranium where postotic laterosensory canal exits supracleithrum. Postcleithral process short, deep and slightly expanded posteriorly. Middorsal groove on nuchal shield usually well-defined. Nuchal foramina present as small lenticular opening partially or wholly replacing suture between anterior nuchal plate and epioccipital. Skin relatively smooth in adults; juveniles with few, very small papillae on snout and upper head not forming distinct ridges.
Dorsal-fin rays I,6; pectoral-fin rays I,9-10 (modally 10); pelvic-fin rays i,6; total anal-fin rays 12-16 (first 4 to 6 unbranched); caudal-fin rays i,8/9,i; dorsal procurrent caudalfin rays 14-19, ventral procurrent caudal-fin rays 13-17. Dorsal-fin spine of moderate length, sturdy, nearly straight (rarely weakly angled) and evenly attenuate with sharp tip; anterior denticulations antrorse, moderately sized and evenly spaced basally, largely absent from distal third; posterior denticulations small, retrorse basally, becoming straight and more spaced distally, present nearly to tip. Pectoral-fin spine sturdy, long, weakly bowed with blunt tip; anterior denticulations antrorse, moderately sized nearly to tip; posterior denticulations strongly retrorse along most of posterior margin, becoming less retrorse distally, moderately sized and relatively uniform along distal half; last denticulation usually subterminal. Pelvic fin of moderate length, rounded. Anal fin triangular, tip of longest branched ray more or less even with vertical through base of last anal fin ray, distal margin nearly straight or very shallowly concave. Caudal fin forked with rounded or weakly pointed lobes.
Coloration in alcohol
. Head and body coloration similar to
L. hasemani
; weakly countershaded, upper sides somewhat uniform tan or light gray, occasionally darker brown (Brazilian specimens). Wide dusky middorsal stripe evident in some specimens, flanked by lighter areas along upper sides. Melanophores sometimes weakly concentrated in skin between and above dorsal wings of midlateral plates, effecting appearance of faint dusky stripe. Lower sides and ventral surfaces white to cream.
Dorsal, anal and paired fins without distinct markings. Dorsal fin with faint stippling on rays and skin covering insertion; darker stippling concentrated along anterior margin of dorsal spine and around perimeter of locking spine. Pectoral and pelvic fins cream to white with faint stippling on dorsal surfaces. Anal fin cream, hyaline. Caudal fin with parallel pair of dusky stripes as in
L. hasemani
.
Distribution and habitat
.
Leptodoras linnelli
is known from the upper río Orinoco (ríos Ventuari and Mavaca) and a tributary of the Casiquiare (río Siapa),
Venezuela
; Atlantic Coast drainages of the Guianas and northern
Brazil
(
e.g.
,
Essequibo
,
Demerara
, Araguari); and the rios Uatumã (Amazonas dr.), Tacutu (Branco dr.) and lower Demini (Negro dr.),
Brazil
(
Fig. 16
). The distribution of
L. linnelli
appears to be restricted to river systems draining the Guiana Shield. Most collections are from whitewater or turbid rivers, often in places with sandy beaches and swift currents (
e.g.
, cataracts).
Type-material examined
.
Leptodoras linnelli
:
holotype
,
FMNH 53561
[ex.
CM 1626
a] (
153.5 mm
),
Potaro river
(Essequibo dr.),
Tumatumari
,
Guyana
, 1908,
C.H. Eigenmann
et al
.
Paratypes
(33 of 36, 3 missing):
Guyana
:
BMNH
1911.10.31.73-74 [ex.
CM 1627
a-e, ex.
IU 12022
] (1 + 1*,
162.2 mm
), same data as holotype
;
BMNH 1911.10
.31.75 [ex.
CM 1627
a-e, ex.
IU 12022
, Tumatumari or ex.
CM 1629
a, ex.
IU 12023
, Crab Falls] (1,
70.9 mm
),
Potaro river
(
Essequibo
dr.),
Tumatumari
or
Essequibo
river (
Atlantic
dr.),
Crab Falls
, 1908,
C.H. Eigenmann
et al
.;
CAS
59775 [ex.
CM 1627
a-e, ex.
IU 12022
] (5,
52.1-173.5 mm
), same data as holotype
;
CAS
59776 [ex.
CM 1629
a, ex.
IU 12023
] (2, 59.28,
86.45 mm
),
Essequibo
river (
Atlantic Dr.
),
Crab Falls
, 1908,
C. H. Eigenmann
et al
.;
CAS
59777 [ex.
CM 1628
, ex.
IU 12024
] (1,
51.9 mm
),
Essequibo
River
(
Atlantic Dr.
),
Rockstone
, 1908,
C. H. Eigenmann
et al
.;
CAS 121940
[ex.
SU 21940
, ex.
CM 1627
a-e, ex.
IU 12022
] (1*,
169 mm
), same data as holotype
;
FMNH 7399
[ex.
CM 1627
a- e, ex.
IU 12022
] (1, 168.0 mm)
,
FMNH 53186
[ex.
CM 1627
a-e, ex.
IU 12022
] (12, 48.9-161.0 mm), same data as holotype
;
FMNH 53187
[ex.
CM 1628
a, ex.
IU 12024
] (
1, 145.1 mm
), same data as CAS
59777;
FMNH 53188
[ex.
CM 1630
] (
1, 138.8 mm
),
Georgetown Market
?, 1908,
C. H. Eigenmann
et al
.;
FMNH 53562
[ex.
CM 1629
a, ex.
IU 12023
] (1, 69.0 mm), same data as CAS
59776;
MCZ
30070 [ex.
CM 1629
a, ex.
IU 12023
] (
1, 151.9 mm
), same data as CAS
59776;
MCZ
30071 [ex.
CM 1627
a-e, ex.
IU 12022
] (1*,
151.9 mm
), same data as holotype
;
NMW
46109 [ex.
CM 1627
a-e, ex.
IU 12022
] (
1, 145.4 mm
), same data as holotype
;
USNM 66222
ex
.
CM 1627
a-e, ex
.
IU 12022
(1*,
144.2 mm
), same data as holotype
;
ZMA 110690
[ex.
CM 1627
a- e, ex.
IU 12022
,
Tumatumari
or ex.
CM 1629
a, ex.
IU 12023
,
Crab Falls
] (1), same data as BMNH
1911.10.31.75.
Fig. 16.
Distributions of
Leptodoras acipenserinus
(solid red circles),
L. linnelli
(solid green circles),
L. nelsoni
(open red circles) and
L. rogersae
(open blue circles) (stars denote type localities).
Non-type material
.
Brazil
:
Amapá
:
INPA 20969
(3, 149-
178mm
)
,
MNHN 1998-0168
(1 + 3*,
153-175.6 mm
)
,
rioAraguari (
Atlantic
dr.), cachoeira (waterfall)
da Capivara
, upstream of
Porto Grande
(
51°52’54.5"W
,
1°2’43.6"N
),
19-22 Aug 1992
.
Amazonas
:
INPA
ex. 17709 (1, 54 mm),
rio Demini
(
Negro
dr.), near mouth of rioAracá,
22 Jun 1993
;
INPA 17721
(1, 45 mm)
,
rio Negro
(
Amazonas
dr.),
Barcelos
,
6 Jul 1994
;
MNHN 1996- 1122
(1*,
200.6 mm
)
,
rio Pitinga
(
Uatumã-Amazonas
dr.),
Cachoeira
40 ilhas,
between Balbina and Pitinga
reservoirs, about
15 km
dowstream of the
Pitinga
dam, 1994.
Roraima
:
INPA 2002
(11)
,
rio Tacutu
(
Branco
dr.),
Bonfim
,
17 Mar 1988
.
Guyana
:
AMNH 214846
(8)
,
Demerara
, 1934;
AMNH 214913
(2)
,
Demerara
, 26
Nov
-1
Dec
, 1934;
ANSP 39734
(
1, 135.3 mm
)
,
Rupununi river
(
Essequibo
dr.), 1911;
ANSP 175880
(3 + 1*,
93.3 mm
)
, isolated stagnant pool/pond (
Essequibo
dr.), some 40 min. from main
Essequibo
river channel (
4°32’43"N
,
58°35’02"W
),
31 Jan 1997
, WGS 97-27;
ANSP 175881
(3)
,
Essequibo
river (
Atlantic
dr.), sandbar ca.
800 m
downstream from
Essequibo
campsite (
Maipuri
) (
4°45’43"N
,
58°45’52"W
),
29 Jan 1997
, WGS 97-25;
ANSP 175882
(1*,
84.8 mm
)
,
Essequibo
river (
Atlantic
dr.), sandbars in vicinity of
Maipuri
campsite (
4°34’17"N
,
58°35’17"W
),
2 Feb 1997
, WGS 97-31;
ANSP 175883
(1*,
94.2 mm
)
,
Essequibo
river (
Atlantic
dr.)
,
Essequibo
campsite (
4°45’41"N
,
58°45’53"W
),
26 Jan 1997
, WGS 97-19;
ANSP 177270
(8)
,
Essequibo
river (
Atlantic
dr.), extensive sandbar
2 km
upstream from Paddle Rock
campsite (
4°42’20"N
,
58°42’26"W
),
25 Nov 1997
, GGW 97-23;
ANSP 177271
(3)
,
Essequibo
river (
Atlantic
dr.), extensive sandbar
500 m
downstream from
Paddle Rock
campsite (
4°44’N
,
58°43’W
),
23 Nov 1997
, GGW 97-17;
ANSP 179177
(15)
,
Takutu river
(
Branco
dr.), ca.
2.75 km
west of
Saint Ignatius
(
3°21’18"N
,
59°49’51"W
),
5 Nov 2002
;
AUM
27943 (8, 50.0-
59.9 mm
)
,
Demerara
River
(
Atlantic
dr.),
5.05 mi
SSW Linden
, bearing 195° (
5°56’N
,
58°18’22"W
),
17-18 Oct 1998
,
Guy
98-6;
INHS 49099
(9, 47.0-
70.4 mm
)
,
same data asAUM 27943
.
Venezuela
:
Amazonas
:
AMNH 91373
(1*,
92.7 mm
)
,
río Mavaca
(
Orinoco
dr.), near base camp at sand beach,
17 Mar 1989
, CJF-AMA 89-21;
AMNH 91374
(3 + 2*,
88.1-99.6 mm
)
,
río Mavaca
(
Orinoco
dr.), 30 min. upriver from base camp, at sand beach on right bank,
10 Mar 1989
, CJF 89-10;
ANSP 180817
(5)
,
río Ventuari
(
Orinoco
dr.), village of
Marueta
at landing,
91 km
east-northeast of
Macuruco
,
159 km
east-northeast of
San Fernando de Atabapo
(
4°18’51"N
,
66°17’32"W
),
6 Apr 2004
, VEN 04-12;
ANSP 180900
(3)
,
río Manapiare
and mouth of
río Yutaje
(
Ventuari
dr.),
14 km
northwest of
San Juan de Manapiare
(
5°26’12"N
,
66°6’45"W
),
13 Apr 2004
, VEN 04-25;
ANSP 180902
(2)
,
río Ventuari
(
Orinoco
dr.), raudales
Tencua
,
56 km
east-southeast of
San Juan de Manapiare
(
5°2’59"N
,
65°37’38"W
),
19 Apr 2004
, VEN 04-31;
ANSP 180903
(2)
,
río Siapa
(
Casiquiare
dr.), raudale
Gallineta
,
142 km
east of
San Carlos de Río Negro
(
1°49’N
,
65°47’41"W
),
17 Mar 2005
, VEN 05-31;
ANSP 180906
(3)
,
río Ventuari
(
Orinoco
dr.), beach at village of
Moriche
,
116 km
northeast of
Macuruco
,
169 km
northeast of
San Fernando de Atabapo
(
4°45’N
,
66°21’13"W
),
7 Apr 2004
, VEN 04-15;
CAS 159157
[ex.
SU 59157
] (3 + 4*,
97.4-125 mm
),
río Casiquiare
, beach at mouth of
Casiquiare
at
Orinoco
bifurcation,
22 Mar 1925
;
MBUCV-V 19288
(1*,
85.8 mm
)
,
río Mavaca
(
Orinoco Dr.
), playa arenosa, rio arriba de campamento,
8 Mar 1989
;
MBUCV-V 19404
(1*,
98.8 mm
)
,
same data as AMNH 91373;
MBUCV-V 19689
(3*,
84.6-100 mm
)
,
same data asAMNH 91374.
Bolivar
:
MBUCV-V 10210
(1,
93.2 mm
)
,
río Cuyuní
(
Essequibo
dr.), isla
de Jacobo
, cerca del raudal
de Kinotovaca
,
26 Feb 1977
;
MBUCV-V 16529
(1*,
110.8 mm
)
,
río Cuyuni
(
Essequibo
dr.),
10 km
oeste del km 88, via
El Dorado-Luedpa
,
Ste. Elena de Vairen
,
12Apr 1987
;
MBUCV-V 16602
(1 + 1*,
157 mm
)
,
same data as MBUCV-V 16529
.
Leptodoras acipenserinus
(
Günther, 1868
)
Figs. 5
d-f, 17, 18a,b and 19a
Oxydoras acipenserinus
Günther 1868
a: 475
(
type
locality:
Xeberos
(=
Jeberos
) near
río Aipana
, small tributary joining
río Huallaga
near the latter’s confluence with
río Marañon
(
Amazonas
dr.),
Loreto
,
Peru
.
Diagnosis
. Distinguished from all
Leptodoras
except
L. linnelli
by having adipose fin extended anteriorly as a low thin ridge of adipose tissue to a point midway between anterior insertion of adipose fin and posterior insertion of dorsal fin. See diagnosis of
L. linnelli
for characteristics distinguishing it from
L. acipenserinus
.
Description
. Morphometrics summarized in
Table 1
. Body very elongate and dorsoventrally depressed, ventrally flattened from snout to vent; head also depressed, short relative to body with comparatively long acute snout; dorsal profile of snout shallowly convex from tip to midway between nares; caudal peduncle long, shallow. Eye moderately sized with weakly developed adipose eyelid.
Mouth subterminal, jaws edentulous in adults, small juveniles with few thin acicular teeth near medial symphysis of dentaries. Maxillary barbel long, usually reaching ventromedial extent of gill opening. Secondary maxillary barbels 9-12 (modally 11), flattened, overlapping proximally, separated distally; proximal secondary maxillary barbels with fimbriate anterior margin and smooth posterior margin; distal ones smooth. Oral hood comparatively short overall, not greatly expanded posteriorly. Upper labial extension elongate, somewhat Lshaped, proximal half straight and narrow, distal half moderately to strongly curved medially and distinctly expanded with wide lateral flap bearing small fimbriae, surface smooth. Lower labial extension narrow, attenuate, finishing before upper labial extension. Interlabial membrane narrow (labial extensions convergent), comparatively thin with few small papillae. Dorsolabial membrane weakly developed, evenly attenuate posteriorly. Two pairs of jaw barbels with scattered elongate papillae; cojoined by basal membrane; outer pair slightly longer than inner pair and shorter than maxillary barbel, cojoined with lower labial extension via narrow membrane. Branchiostegal membrane with moderately expanded fleshy margin overlapping ventral gill opening; fleshy inner flap along cleithrum usually complete, nearly reaching cleithral notch. Morphology of first gill arch similar to
L. linnelli
.
Fig. 17.
Leptodoras acipenserinus
, FMNH
92385 (SL 196.5 mm), río Bobonaza (Pastaza–Marañon dr.), Ecuador.
Fig. 18.
Juvenile and subadult
Leptodoras
(Amazon basin). a.
L. acipenserinus
, FMNH
97140 (SL 113.3 mm), río Coca (Napo dr.), Napo, Ecuador. b.
L. acipenserinus
, ANSP
178467 (SL 107.9 mm), río Nanay, Loreto, Peru. c.
L. cf. cataniai
Nanay
form, INHS 39814 (SL 109.2 mm), río Nanay, Loreto, Peru. d.
L. cf. cataniai
Amazon
form, ANSP 180925 (SL 120.3 mm), rio Iça, Amazonas, Brazil. e.
L. cataniai
, ANSP
180912 (SL 104.6 mm), rio Negro, Amazonas, Brazil.
Fig. 19.
Live coloration in
Leptodoras
.
a.
L. acipenserinus
,ANSP
178467 (SL 108 mm), río Nanay (Amazonas dr.), near Iquitos, Loreto, Peru. b.
L. cf. cataniai
Nanay
form, ANSP 179863 (SL 144 mm),
ibid.
c.
L. myersi
, ANSP
181045 (SL 78.6 mm), río Amazonas, near Iquitos, Loreto, Peru.
Sum of midlateral plates 77-86 (modally 82, Table 3). Anterior midlateral plates deep, covering at least half of corresponding body depth; posterior margins of dorsal and ventral wings rounded with many small serrae. Tympanum usually with 3 distinct ossifications (simple or dual spines) along postotic laterosensory canal; small fixed spine usually conspicuous along posterior margin of neurocranium where postotic laterosensory canal exits supracleithrum. Postcleithral process rather robust, short and very deep, distal portion dome shaped with straight ventral margin. Middorsal groove on nuchal shield usually well-defined. Subrectangular nuchal foramina present, replacing suture between epioccipital and anterior nuchal plate. Skin often with distinct fleshy papillae on snout and upper head; papillae consolidated to form low pair of ridges on middorsal snout and additional ridges along margins of orbit and middorsal groove on nuchal shield.
Dorsal-fin rays I,6; pectoral-fin rays I,9-11 (modally 10); pelvic-fin rays i,6; total anal-fin rays 14-17 (first 4 or 5 unbranched); caudal-fin rays i,8/9,i; dorsal procurrent caudalfin rays 14-19, ventral procurrent caudal-fin rays 14-19. Dorsal-fin spine of moderate length, comparatively thin, nearly straight, evenly attenuate with sharp tip; anterior denticulations antrorse, rather small and crowded basally, absent from distal tip; posterior denticulations retrorse to straight, weak, rather inconspicuous. Pectoral-fin spine sturdy, relatively short, anterior margin weakly curved, posterior margin straight, tip blunt; anterior denticulations antrorse, moderately sized nearly to tip; posterior denticulations becoming gradually larger and less retrorse towards tip of spine (last and/or penultimate denticulation nearly perpendicular to long axis of spine); last posterior denticulation terminal, its lateral margin continuous with tip of pectoral spine. Pelvic fin of moderate length with straight to weakly rounded distal margin. Anal fin triangular with elongate base; tip of longest branched ray falls well short of vertical through base of last branched ray when fin extended. Caudal fin deeply forked with elongate and pointed lobes.
Coloration in alcohol
. Head and body moderately countershaded, upper sides tan or gray-brown, lower sides and undersurfaces white. Wide dusky middorsal stripe usually evident, flanked by lighter areas along upper sides. Melanophores sometimes weakly concentrated in skin between and above dorsal wings of midlateral plates, forming faint dusky stripe.
Dorsal fin with faint stippling on rays, membranes depigmented, clear; darker stippling along anterior margin of dorsal spine and on skin surrounding dorsal-locking spine and along fin insertion. Pectoral fin with faint stippling on anterior rays and membranes, posterior rays and membranes depigmented, melanophores most concentrated on skin between posterior denticulations of pectoral spine. Pelvic fins with faint stippling on dorsal surfaces. Anal fin cream, hyaline. Elongate preadipose ridge light (depigmented) and often well contrasted with dusky middorsal stripe. Caudal fin with divergent pair of broad diffuse stripes, one on lower half of upper lobe and other on upper half of lower lobe; lower stripe distally expanded along margin of ventral-most rays and membranes.
Coloration in life
. Live specimens from the río Nanay,
Peru
, are light olive in dorsal half of head and body; basal portions of dorsal and caudal fins also with light olive tinge (
Fig. 19a
).
Distribution and habitat
.
Leptodoras acipenserinus
is known from widely separate sites along the cis-Andean piedmont in the upper Amazon basin in
Ecuador
,
Peru
and
Brazil
(
Fig. 16
). Most specimens are from upland areas in the upper Napo,
Marañon
(
i.e.
, Huallaga and Pastaza), Ucayali and upper Madeira (
i.e.
, Guaporé and Madre de Dios) systems. A few specimens have been collected in lowland tributaries of the río Amazonas (
i.e.
, Itaya and Nanay) near Iquitos.
Leptodoras acipenserinus
has not been found in or near the main channel of the río Amazonas downstream of Iquitos. Most specimens are from whitewaters, however this species inhabits moderately blackwater rivers as well (
e.g.
, río Nanay). In the río Nanay it was collected at night with
Leptodoras cf. cataniai
over a large sandy beach in swift-flowing water.
Type-material examined
.
Oxydoras acipenserinus
:
holotype
(unique),
BMNH 1867.6
.13.32 (178.0 mm), Xeberos,
upper
Amazons
, E. Bartlett [Xeberos (= Jeberos) is a village in the Peruvian Amazon (Department
Loreto
) near the río Aipana, a small tributary that joins the río Huallaga near the latter’s confluence with the río
Marañon
(
Amazonas
Dr.)]
.
Non-type material
.
Brazil
:
FMNH 58189
(3, 110.5-
119.5 mm
),
rio Guaporé
(
Mamoré-Madeira
dr.),
Maciel
,
23 and 26 Jul 1909
.
Ecuador
:
FMNH 88186
(1, 171.0 mm),
FMNH 93040
(
1, 171.5 mm
),
río Bobonaza
(
Pastaza-Marañon
dr.),
Montalvo
,
Aug 1958
;
FMNH 88198
(3, 129.7-157.0 mm),
FMNH 92625
(2, 122.0,
136.5 mm
),
río Bobonaza
(
Pastaza-Marañon
dr.),
Morete Bobonaza
,
Feb 1958
;
FMNH 92385
(2*,
155, 196.5 mm
),
FMNH 92624
(2, 202.0, 203.0 mm),
río Bobonaza
(
Pastaza-Marañon
dr.),
Morete Bobonaza
,
Nov 1958
.
Napo
:
FMNH 97140
(1*,
113.3 mm
)
río Coca
(
Napo
dr.),
7 km
upstream from confluence with
Napo
(
0°24’36"S
,
76°59’0"W
),
23 Sep 1981
,
DJS 81-15;
FMNH 97141
(2, 115.0,
116.1 mm
), río
Napo
(
Amazonas
dr.),
10.7 km
upstream from bridge at
Coca
in main stream (
0°32’36"S
,
77°2’54"W
),
21 Sep 1981
,
DJS 81-11;
FMNH 97142
(
1, 134.2 mm
), río
Napo
(
Amazonas
dr.),
Pompeya
, north shore and tower end of sandy island in center of river (0°26.5', 76°38.2'),
7 Oct 1981
,
DJS 81-42;
FMNH 97143
(2*, 131.5,
150.9 mm
),
río Payamino
(
Napo
dr.),
23.3 km
upstream from confluence with
Napo
(0°26.9', 77°6.2'),
20 Sep 1981
,
DJS 81-6;
FMNH 97144
(1, 167.0 mm) río
Napo
,
río Coca
(
Amazonas
dr.), cocha off mainstream (
0°27’12"S
,
76°59’24"W
),
26 Sep 1981
,
DJS 81-24;
FMNH 97145
(1*, 161.0 mm),
río Aguarico
(
Napo
dr.), near
Destacamento
militar
Cuyabeno
and confluence of
Cuyabeno
and
Aguarico
(0°15.6', 75°53.9'),
21 Oct 1983
,
DJS 83-47;
MCZ
48624 (1*,
141 mm
), río
Napo
(
Amazonas
dr.), sand bank opposite
Coca
,
1 Dec 1971
, TRR71:1201B.
Peru
:
Loreto
:
ANSP 178464
(1 + 1*,
108.1 mm
),
río Itaya
(
Amazonas
dr.), bridge on
Iquitos-Nauta
highway, approximately
25 miles
south-southwest of
Iquitos
,
8 Aug 2001
,
Peru
2001-03;
ANSP 178467
(13 + 3*,
107.5-107.9 mm
),
río Nanay
(
Amazonas
dr.),
Pampa Chica
, village
4.54 km
west of
Iquitos
,
2 Aug 2001
,
Peru
2001-02.
Madre de Dios
:
ANSP 180550
(1), río
Madre de Dios
(
Madeira
dr.)
,
Isla
Rolin
, ca. 1 hour by boat downstream from
Puerto Maldonado
(
12°33’50"S
,
69°03’01"W
),
29 Jul 2004
,
TCEP 04-52
;
ANSP 180630
(1),
río Tahuamanu
(
Orton-Madre de Dios
dr.), vicinity of
San Lorenzo
(
11°27’46"S
,
69°18’23"W
),
1 Aug 2004
,
TCEP 04-54
;
FMNH 70286
(1*, 169.0 mm),
Boca Amigo
,
8 Nov 1954
;
CAS
59426 (2, 64.7,
99.5 mm
), río
Madre de Dios
(
Madeira
dr.), on east end, north side of island opposite
Cuzco-Amazonico
lodge,
4 Jun 1983
.
Ucayali
:
USNM 261478
(3,
76.5-86.6 mm
),
río Aguaytia
(
Ucayali
dr.),
Nuevo Requena
,
24 Oct 1973
.