Open Access PDF - Sven Kullander

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Rio Negro specimens. Three specimens (MZUSP
92401) from the middle Rio Negro are tentatively
referred to C. nigromaculata. A morphometric
PCA (not shown) of C. ocellaris and C. nigromaculata
clusters the Rio Negro specimens with
Orinocoan C. nigromaculata rather than with
C. ocellaris, but in the total analysis (Fig. 3) they
fall within the overlap with the C. temensis group,
together with C. monoculus and C. orinocensis. The
larger specimens are overall dark, with dark
vertical bars not contrasted, and without distinct
pattern of black spots on the side. All possess
distinct bars 1-3, which widest dorsally and
gradually narrower almost to a point ventrally;
and with less distinct bars 1a and 2a.
Geographical distribution. Upper Orinoco and
Casiquiare tributaries and the middle Rio Negro
(Fig. 23).
Notes. Jardine (1843) reported four species of
Cichla observed and drawn by Schomburgk in
the Rio Negro basin. Cichla argus is identifiable
from the drawing as C. orinocensis. Cichla trifasciata
and C. flavomaculata possess the typical narrow
dark bars on the side, and C. flavomaculata
also the regular lines of yellow spots along the
side, characteristic of C. temensis. The drawing of
C. nigromaculata (Jardine, 1843: pl. 7) shows a fish
with green dorsal side, yellowish lower side, blue
dorsal fin and upper half of caudal fin, and reddish
pelvic, anal and lower part of caudal fin.
Numerous black blotches are present on the head,
dorsum, and abdominal side, and on the dorsal
side one can distinguish four, maybe five principal
dark blotches, which appear to be narrowly
ocellated. The colour pattern resembles that of
C. monoculus, which, however, is not known from
the upper Rio Negro. Cichla ocellaris is the next
most similar species in the area, but it does not
show more than three prominent blotches or bars
on the dorsal side. None of the species of Cichla
in the upper Rio Negro shows numerous large
black spots on the side of the head. The figure is
apparently not correct to details, but is understood
by us to depict a Cichla with prominent black
markings on the side.
Three specimens from the upper Rio Orinoco
and Casiquiare, here identified as C. nigromaculata,
depart from other Cichla in the area in displaying
five dark bars dorsally on the side, and
the larger specimen also several black blotches,
whereby it resembles the colour pattern on the
drawing of C. nigromaculata (Jardine, 1843: pl. 7).
They differ from that drawing in absence of dark
blotches on the side of the head, in having a more
prominent caudal-fin ocellus, and in having well
defined vertical bars instead of dorsal blotches.
Two of the specimens are immature and do not
show extensive black blotches dorsally on the
side. The third is an adult female with a significant
number of black blotches on the side. The drawing
probably shows a breeding male as indicated
by the prominent nuchal hump, and it is possible
that males are more speckled than females.
The two species of Cichla confirmed for the
Rio Negro, C. orinocensis and C. temensis, never
show a colour pattern with extensive dark markings
on the side. The colour pattern of C. nigromaculata
as illustrated by Jardine (1843) is compatible
with that of C. monoculus, C. ocellaris, and the
species herein reported as C. nigromaculata.
The three Orinoco-Casiquiare specimens come
from distant localities in the upper Rio Orinoco
region, in rivers eroding the Serra Parima, separating
the Orinoco from the Rio Branco headwaters,
but a region travelled by Schomburgk. Three
other, tentatively assigned specimens were collected
in the middle Rio Negro together with
C. orinocensis, and not far from the Rio Padauiri,
mentioned by Schomburgk as an observation site
for C. nigromaculata.
The material that we identify as C. nigromaculata
is most similar to C. ocellaris, particularly in
the presence of bars 1a and 2a, and the enlarged
dorsally positioned blotch in bar 3. However, the
absence of postorbital markings, and suggested
strongly pigmented occipital bar in the large female
from Rio Mavaca are more indicative of
C. monoculus.
Cichla nigromaculata differs from C. ocellaris
from the Rio Branco and the Guianas in average
higher E1 row scale counts (75-84, vs. 67-82; Table
2). Cichla nigromaculata always has an interrupted
lateral line, whereas in C. ocellaris the
condition is variable. In practically all specimens
of C. ocellaris from the Suriname and Marowijne
rivers the lateral line is continuous (Kullander &
Nijssen, 1989: 13), but in Guyana and the Rio
Branco the condition varies. In 10 specimens of
C. ocellaris from the Rio Branco the lateral line is
continuous bilaterally in one, and on one side in
two. Cichla nigromaculata has a shallower caudal
peduncle than C. ocellaris of similar size: depth
10.3-11.4 % SL vs. 11.9-13.2 % SL in specimens
over 100 mm SL. In the colour pattern, the shape
Kullander & Ferreira: Review of Cichla