10A. Dentaries with a few small, but distinct acicular
teeth; dorsal and lateral surfaces mottled with large, well
spaced melanophores, some loosely arranged to form irregular
blotches; Orinoco Basin.....Leptodoras sp. 4
(aff. myersi)
10B. Dentaries edentulous (except in small juveniles
of some Amazon species); dorsal and lateral surfaces not
mottled.....11
11A. Distal half of dorsal fin with distinct black
spot or blotch.....Leptodoras hasemani
11B. No black spot or blotch on distal half of dorsal
fin.....12
12A. Dorsal spine thin and greatly extended as a long flexible
filament; predorsal distance relatively short, 26–28%
of SL; bases of dorsal and paired fins with intense black
pigment.....Leptodoras juruensis
12B. Dorsal spine not greatly extended as a long
flexible filament (except in a few rare instances); predorsal
distance longer, >=30% of SL; pigmentation on bases of
dorsal and paired fins variable.....13
13A. Broad dusky nuchal saddle extending ventrally
across tympanum and humeral process, finishing on the lower
side level with the pelvic-fin origin.....Leptodoras
myersi
13B. No dark nuchal saddle and bar on side of body.....14
14A. Flap-like posterior extensions at corners of
lower lip narrow and long, finishing beyond tips of similar
extensions at corners of upper lip; black melanophores concentrated
on basal portions of dorsal spine and usually fin.....15
14B. Flap-like posterior extensions at corners of lower
lip relatively short, finishing even with or before tips
of similar extensions of upper lip; base of dorsal fin without
intense black pigmentation (may appear dusky, but never
black).....16
15A. Anterior midlateral plates shallow, height of
2nd midlateral plate less than or equal to vertical diameter
of eye; anterior nuchal plate usually narrow, permitting
suture between supraoccipital and middle nuchal plate; profile
of snout weakly concave.....Leptodoras praelongus
15B. Anterior midlateral plates deeper, height of
2nd midlateral plate distinctly greater than vertical diameter
of eye; anterior nuchal plate usually expanded laterally
and sutured to epioccipital; profile of snout rounded (convex).....Leptodoras
copei
16A. Upper labial extension relatively long with
narrow base and expanded distal portion that curves medially
and has a distinctly pointed or triangular-shaped tip; dorsolabial
membrane well-developed, widely rounded posteriorly; humeral
process relatively short, usually 19.3–28.5 times into
SL…..17
16B. Upper labial extension (excluding small fimbriae)
with rounded or truncate distal tip; dorsolabial membrane
weakly to moderately developed, evenly attenuate posteriorly;
humeral process longer, 13.9–19.2 times into SL…..19
17A. Adipose eye relatively large, horizontal length
1.49–1.79 times into postorbital distance and 23.1–27.8%
of predorsal distance; blackwaters of Negro Basin and Casiquiare…..Leptodoras
sp. 3 (Negro form)
17B. Adipose eye smaller, horizontal length 1.81–2.27
times into postorbital distance and 18–23.2% of predorsal
distance; white to moderately blackwaters of Amazon Basin…..18
18A. Snout relatively long, length 1.06–1.22
times postorbital distance, 42.4–46.6% of predorsal
distance; sum of midlateral scutes 79–86 (modally 82)…..Leptodoras
sp. 3 (Nanay form)
18B. Snout shorter, length 0.85–1 times postorbital
distance, 37.6–41.3% of predorsal distance; sum of
midlateral scutes 83–92 (modally 88)…..Leptodoras
sp. 3 (Amazon form)
19A. Adipose eye relatively large, horizontal length
11.2–13.9 times into SL; predorsal distance relatively
long, 35.5–38.7% of SL; thin low pre-adipose ridge
always present…..20
19B. Adipose eye smaller, horizontal length usually
14.5–20.6 times into SL; predorsal distance somewhat
shorter, 31.6–36.5% of SL; preadipose ridge absent
or only weakly developed…..21
20A. Postorbital length 37.6–41.8% of predorsal
distance…..Leptodoras linnelli
20B. Postorbital length 42.9–44.6% of predorsal distance…..Leptodoras
sp. 2 (Orinoco)
21B. Postorbital length 1.8–2.01 times distance
from snout tip to anterior nares; snout length 37.8–41.8%
of predorsal distance; anterior scutes comparatively shallow,
covering between 1/4 and 1/2 of corresponding body depth;
sum of midlateral scutes 82–86 (modally 84); Orinoco
Basin…..Leptodoras sp. 2 (Orinoco)
21A. Postorbital length 1.22–1.81 times distance
from snout tip to anterior nares; snout length 41.6–46.5%
of predorsal distance; anterior scutes deep, covering >=
half of corresponding body depth; sum of midlateral scutes
74–86; Orinoco and Amazon basins…..22
22A. Thin low middorsal ridge of adipose tissue extending
from adipose fin to point midway between anterior base of
adipose fin and posterior base of dorsal fin; Upper Amazon
Basin…..Leptodoras acipenserinus
22B. Preadipose ridge absent or only weakly developed,
falling well short of point midway between anterior base
of adipose fin and posterior base of dorsal fin; Orinoco
Basin…..Leptodoras sp. 1
(Apure/Meta)
All photo's by author.
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of Natural Sciences of Philadelphia Biodiversity Research
Group page which links to the ALL
CATFISH SPECIES PROJECT whose mission is to facilitate
the discovery, description and dissemination of knowledge
of all catfish species by a global consortium of taxonomists
and systematists.
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Leptodoras hasemani |
