Taxonomic assessment of Leptodoras (Siluriformes: Doradidae) with descriptions of three new species
Sabaj, Mark Henry
Neotropical Ichthyology
2005
2005-12-31
3
4
637
678
3TNX8
Sabaj, 2005
Sabaj
2005
[302,513,608,632]
Actinopterygii
Doradidae
Leptodoras
Animalia
Siluriformes
26
663
Chordata
species
nelsoni
sp. nov.
Figs. 4f, 5b, 15dand 20
Holotype. ANSP 180917(1*, 117 mm), Colombia, Meta, río Metica(Meta-Orinoco dr.), ca. 1.5 kmeast of Rajote, Plancha267 ( 3°56’N, 73°3’W), 19 Mar 1973, W.G. Sauland W.F. Smith- Vaniz, BSS-14. Paratypes(35). Colombia: Meta: AMNH 236112[ex. ANSP 134667] ( 1, 103.7 mm), río Metica( Meta-Orinocodr.), ca. 3 kmsoutheast of Hacienda Mozambique( 3°57’N, 73°2’W), 30 Mar 1975, BSF-26; ANSP 131336(2, 99.2-111 mm), same data as holotype; ANSP 134665(2 + 1*, 113.8 mm), Río Metica(Meta- Orinocodr.), ca. 3 kmsoutheast of Hacienda Mozambique( 3°57’N, 73°2’W), 24 Mar 1975, BSF-9; ANSP 134666(1, 86.9 mm), río Metica( Meta-Orinocodr.), ca. 3 kmsoutheast of Hacienda Mozambique( 3°57’N, 73°2’W), 20 Mar 1975, BSF- 1; ANSP 134667(1 + 1*, 92.3 mm), same data asAMNH 236112; AUM28764 (1, 75.5 mm), río Manacacías( Meta-Orinocodr.), 7 kmsouth-southeast of Puerto Gaitánat sandbar on left (west) bank, 9 Oct 1978, JSR 78-35; CAS 222740[ex. ANSP 134665] (1*, 97.9 mm), same data as ANSP 134665; FMNH 117083[ex. ANSP 134665] ( 1, 104.7 mm), same data as ANSP 134665; ICNMHN 13571 [ex. ANSP 134667] (1, 95 mm), same data as AMNH 236112; MNHN 2003-0355[ex. ANSP 134665] (1), UMMZ 245737[ex. ANSP 134665] (1 + 1*, 105.5 mm), USNM 384342[ex. ANSP 134665] (1*, 116.7 mm), same data as ANSP134665. Venezuela: Apure: ANSP 179101( 1, 100 mm), río Apure( Orinocodr.), upriver of San Fernandoand downriver of mouth of río Portuguesa, JNB-84- V4; ANSP 182200[ex. MBUCV-V 14769] (1*, 162 mm), ríoApure ( Orinocodr.), isla del medio (extremo oeste), 7 Aug 1984; MBUCV-V 10941( 1, 104 mm), río Apure( Orinocodr.), frente a isla Apurito, 5 Apr 1978; MBUCV-V 14769(1 + 3*, 93.3-135.8 mm), same dataasANSP 182200; MBUCV-V 15215( 1, 101.9 mm), ríoApure ( Orinocodr.), in front of Jarinalagoon, 25 Jan 1984; MBUCV- V23693(4, 105- 131 mm), caño Bucaral( Orinocodr.), hacia la boca con elArauca, 9 Aug 1984; MBUCV-V 24649( 2, 124, 151 mm), río Apure( Orinocodr.), in front of Jarinalagoon, near San Fernandode Apure, 21 May 1983; MBUCV-V 24659(3, 105- 128 mm), río Apure( Orinocodr.), frente al Aeuropuerto, 18 Feb 1982; MCNG 13167(1, 93.0 mm), río Apure( Orinocodr.), 12 kmrio abajo de San Fernandode Apure, 16 May 1985, DCT85-13. Non-type material (7). Colombia: ANSP 149924(1, 69.6 mm), río Meta( Orinocodr.), Llanos Districtnear Bogota, pre-1973; FMNH 73408(1, 75.0 mm), río Guaviare( Orinocodr.), near Mapiripana( 2°45’N, 71°W), Dec 1957, SW 57-1. Venezuela: Apure: MBUCV- V10856(2), río Apure( Orinocodr.), Aeropuerto de San Fernandode Apure, 21 Jan? 1958; MBUCV-V 10879(1, 58.2 mm), río Apure( Orinocodr.), Jan? 1951; MCNG 13887(1 + 1*, 123.5 mm), río Apure( Orinoco Dr.), 10 kmrio abajo de San Fernandode Apure, 15 May 1985, DCT85-11.
Diagnosis. Distinguished among Leptodorasby the following combination: upper labial extension L-shaped, distal half moderately to strongly curved and distinctly expanded with wide lateral flap bearing small fimbriae, sum of midlateral plates modally 78, plates deep, covering more than 1/2 of body depth, adipose eye weakly developed, preadipose ridge lacking.
Description. Morphometrics summarized in Table 1. Overall shape nearly identical to that of L. acipenserinus; body very elongate and dorsoventrally depressed, ventrally flattened from snout to vent; head depressed, short relative to body with long acute snout; dorsal profile of snout shallowly convex from tip to midway between nares; caudal peduncle long, shallow, depressed. Eye moderately sized, more or less centered between snout tip and origin of dorsal-spine, adipose eyelid weakly developed. Mouth subterminal, jaws edentulous in adults and juveniles as small as 70 mmSL; smaller specimens not examined, but expected to have few thin acicular teeth near medial symphysis of dentaries. Maxillary barbel long, usually reaching ventromedial extent of gill opening. Secondary maxillary barbels 8-11 (modally 10), 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, morphology similar to that of L. acipenserinus. 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 narrow fleshy margin weakly overlapping ventral gill opening; fleshy inner flap along cleithrum nearly complete. Morphology of first gill arch similar to L. linnelli. Sum of midlateral plates 74-80 (modally 78, 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 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 short and deep, distal portion dome shaped with straight ventral margin. Subrectangular nuchal foramina present, replacing suture between epioccipital and anterior nuchal plate. Middorsal groove on nuchal shield usually well defined. Skin with many small fleshy papillae on dorsal surface and sides of snout, papillae somewhat enlarged on medial portion. 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 to 6 unbranched); caudal-fin rays i,8/9,i; dorsal procurrent caudalfin rays 14-18, ventral procurrent caudal-fin rays 12-16. Dorsal-fin spine of moderate length and width, nearly straight, evenly attenuate with sharp tip; anterior denticulations antrorse, moderately sized and crowded basally, absent from distal tip; posterior denticulations weakly retrorse to straight, weak, rather inconspicuous. Pelvic fins of moderate length with rounded to weakly pointed distal margin. Pectoral-fin spine, anal fin and caudal fin as described for L. acipenserinus. Fig. 20. Leptodoras nelsoni, paratype ANSP 182200 (SL 162 mm), río Apure (Orinoco dr.), Apure, Venezuela. Coloration in alcohol. Coloration of L. nelsoniis largely as described for L. acipenserinuswith two exceptions: divergent pair of dusky stripes on caudal fin very distinct and nuchal foramina often dark gray with dense concentration of melanophores in overlying skin.
Distribution and habitat. Leptodoras nelsoniis presently known from a few east-flowing tributaries of the middle Orinoco: río Guaviareand upper Metain Colombiaand río Apurein Venezuela( Fig. 16). Its distribution likely encompasses other large left-bank tributaries of the Orinoco throughout the cis-Andean piedmont and llanos. Leptodoras nelsonipresumably occupies large river habitats similar to those noted for L. acipenserinus( e.g., whitewaters, swift currents near sandy beaches).
Etymology. Named in honor of Douglas Nelson, for his dedicated service to the ichthyological community since 1983 as Collection Manager of Fishes, University of Michigan Museum of Zoology.
1973-03-19
ANSP
W. G. Saul & Vaniz
Colombia
rio Metica
3.9333334
Plancha
1307
-73.05
Rajote
26
663
ANSP 180917
1
Meta
holotype
AMNH, ANSP
Meta-Orinoco
Colombia
Hacienda
rio Metica
26
663
AMNH 236112, ANSP 134667
1
Meta
paratype
1975-03-30
ANSP
W. G. Saul & Vaniz
Mozambique
rio Metica
3.95
Plancha
1307
-73.03333
Rajote
26
663
ANSP 131336
1
Meta
paratype
ANSP
Mozambique
Rio Metica
Hacienda
Orinoco
26
663
ANSP 134665
1
Meta
paratype
1975-03-24
ANSP
Meta-Orinoco
Mozambique
3.95
Hacienda
1307
-73.03333
rio Metica
26
663
ANSP 134666
1
paratype
1975-03-20
ANSP
Meta-Orinoco
Mozambique
3.95
Hacienda
1307
-73.03333
rio Metica
26
663
ANSP 134667
1
paratype
AUM 28764
AUM
Mozambique
rio Manacacias
Puerto Gaitan
Meta-Orinoco
26
663
1
paratype
AUM 28764
1978-10-09
CAS, ANSP
Mozambique
rio Manacacias
Puerto Gaitan
Meta-Orinoco
26
663
CAS 222740, ANSP 134665
1
paratype
AUM 28764
1978-10-09
FMNH, ANSP
Mozambique
rio Manacacias
Puerto Gaitan
Meta-Orinoco
26
663
FMNH 117083, ANSP 134665
1
paratype
AUM 28764
1978-10-09
ANSP
Mozambique
rio Manacacias
Puerto Gaitan
Meta-Orinoco
26
663
ANSP 134667
1
paratype
AUM 28764
1978-10-09
MNHN, ANSP, UMMZ, USNM
Mozambique
rio Manacacias
Puerto Gaitan
Meta-Orinoco
26
663
MNHN 2003-0355, ANSP 134665, UMMZ 245737, USNM 384342
1
paratype
ANSP, V
Orinoco
Venezuela
San Fernando
Orinoco
26
663
ANSP 179101, V4, ANSP 182200, MBUCV-V 14769
1
Apure
paratype
1984-08-07
Apurito
Venezuela
Orinoco
26
663
MBUCV-V 10941
1
Apure
paratype
1978-04-05
Orinoco & Jarina
Venezuela
26
663
MBUCV-V 14769, MBUCV-V 15215
1
Apure
paratype
V 23693
1984-01-25
V
Venezuela
Orinoco
Bucaral
26
663
1
Apure
paratype
1984-08-09
Jarina & San Fernando
Venezuela
Orinoco
26
663
MBUCV-V 24649
1
Apure
paratype
1983-05-21
Orinoco & Aeuropuerto
Venezuela
Apure
26
663
MBUCV-V 24659
1
Apure
paratype
1982-02-18
MCNG
de San Fernando
Venezuela
Orinoco
26
663
MCNG 13167
1
Apure
paratype
ANSP
Orinoco
Colombia
Llanos District
26
663
ANSP 149924
1
Meta
1957-12
FMNH
Orinoco & Mapiripana
Colombia
2.75
Guaviare
0
-71.0
26
663
FMNH 73408
1
Guaviare
[1204,1481,307,328]
Venezuela
Apure
26
663
1
Apure
V 10856
V
Venezuela
Orinoco
Jan
Aeropuerto de San Fernando
26
663
1
Apure
Orinoco & Jan
Venezuela
Apure
26
663
MBUCV-V 10879
1
Apure
1985-05-15
MCNG
Orinoco Dr. & de San Fernando
Venezuela
Apure
26
663
MCNG 13887
1
Apure