Description:
Dorsal spines (total): 2; Dorsal soft rays (total):
6; Anal soft rays: 23 - 30; Vertebrae: 39 - 43. Tympanopleura
atronasus is distinct from other congeners in
having the greatest number of pleural ribs (7-8 pairs
vs. 4-6 in all other species). It differs from other
congeners by the following combination of characters:
a large, dark patch of dense melanophores concentrated
on the flank above the anal fin (vs. diffuse pigment
or unpigmented), longitudinal black to purplish stripe
in each caudal-fin lobe (vs. absent), a broad, black
crescent on the chin (vs. diffuse pigment or unpigmented,
except T. cryptica ). It is distinguished
from T. cryptica in having fewer gill rakers
(14-23, mode 16 vs. 21-26, mode 22), more preanal
vertebrae (16-19 vs. 14-15), more total vertebrae
(39-43, mode 41 vs. 38-41, mode 38), and a shorter
distance between pectoral- and dorsal-fin origins
(15.7-20.9% SL vs. 21.6- 24.3% SL). It can be diagnosed
from T. brevis in having fewer anal-fin rays
(23-30 vs. 31- 36), fewer pectoral-fin rays (7-9 vs.
10-12), fewer gill rakers on the first arch (14-23,
mode 16 vs. 20-24, mode 23), more preanal vertebrae
(16-19 vs. 14-15), and shorter distance between pectoral-
and dorsal-fin origins (15.7-20.9% SL vs. 21.4-27.0%
SL). It can be distinguished from T. longipinna
in having fewer anal-fin rays (23-30 vs. 32-42), fewer
pectoral-fin rays (7-9 vs. 10-13), fewer gill rakers
(14- 23, mode 16 vs. 19-25, mode 23), more preanal
vertebrae (16-19 vs. 13-15), fewer total vertebrae
(39-43, mode 41 vs. 40-43, mode 43), greater prepelvic
length (49.2-55.2% SL vs. 38.8-48.4% SL), and a shorter
anal-fin base (22.1-27.6% SL vs. 33.9-39.9% SL). It
can be separated from T. piperata in having
fewer anal-fin rays (23-30 vs. 31-38), fewer gill
rakers (14-23, mode 16 vs. 16-23, mode 19), more preanal
vertebrae (16-19, mode 17 vs. 14-16, mode 15), more
total vertebrae (39-43, mode 41 vs. 39-41, mode 40),
greater prepelvic length (49.2-55.2% SL vs. 41.3-47.0%
SL), shorter anal-fin base (22.1-27.6% SL vs. 30.9-39.3%
SL), presence of paired posterior diverticula on the
gas bladder (vs. absent), and absence of a transverse,
hourglass-shaped bar of pigment on the base of the
caudal fin (vs. usually present). It can be diagnosed
from T. rondoni in having fewer anal-fin
rays (23-30, mode 27 vs. 28-37, mode 31), fewer pectoral-fin
rays (7-9 vs. 10-13), fewer gill rakers (14-23 vs.
24-33), more preanal vertebrae (16-19, mode 17 vs.
14-16, mode 15), more total vertebrae (39-43, mode
41 vs. 38-42, mode 40), shorter, non-recurved posterior
diverticula on gas bladder (Fig. 6a, b), larger eye
diameter (16.0-27.8% HL vs. 8.4-17.0% HL), and absence
of prominent, irregular spots distributed extensively
on the head and body (vs. present). It attains a considerably
larger maximum size (about 116 mm SL) than T.
cryptica, T. longipinna, and T.
piperata (all less than about 80 mm SL) (Walsh,
Stephen J. et al). Aquarium Care:
Although of a smaller size to its close relative,
Ageneiosus, they could still prove to be
predatory as per this genera, so would need to be
kept with fish that are not too small. Diet:
Presumably meat based. Etymology:
The genus name Tympanopleura: tympano-, tympanum;
pleuro, side, referring to prominent pseudotympanum
consisting of an area on side of body devoid of epaxial
musculature where gas bladder contacts internal coelomic
wall. The specific name atronasus: atrum,
black; nasus, nose, referring to intense black pigmentation
on tip of snout in live and freshly preserved specimens.
Common
Name:
None
Synonyms:
Ageneiosus atronasus
Family:
Auchenipteridae
Distribution:
South America:
Middle and upper Amazon River basin.
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