Open Access PDF - Sven Kullander

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material is 220 mm, but he figures a large adult,
360 mm, with three distinct ocelli on the side, and
lists a 617 mm specimen from the Sección de
Osteologia del Aquarium Agustín Codazzi (no
number, not listed in Machado-Allison, 1973: 158)
in table 2. Machado-Allison (1973: 158) lists 6
skeletal preparations 215-334 mm SL. Since the
617 mm specimen is the only specimen in that
paper stated to possess a continuous lateral line
and an elevated number of lateral line scales (97,
vs. upper + lower lateral line 73-88 recorded for
other C. orinocensis in that paper), the identification
is recorded here with reservation.
Williams et al. (1998: 178) reported specimens
up to 56.5 cm TL (corresponding to ca 46 cm SL)
from the Guri reservoir, but their figure of size
distributions (fig. 2) shows a specimen in the
interval 65-70 cm TL. Winemiller (2001: 98) reported
C. orinocensis up to 455 mm SL in rivers
and 550 mm SL in reservoirs.
Cichla orinocensis can be distinguished from
all other Cichla species by the adult colour pattern,
which typically includes three prominent black,
ocellated blotches on the side, but no additional
blotches on the dorsum (Fig. 15). The ocellated
blotches develop gradually and directly from dark
blotches along the midline of the side, and vary
considerably in appearance in adults (Figs. 15-19).
This variation is well covered by Román (1981),
with illustrations of “typical” individuals with
distinct ocelli (pp. 19, 27, 36, 49, 53, 70, 73, 105,
113, 122, and 129), varying with respect to the
background colour pattern, and both including
specimens with golden or silvery specks on the
black blotches and specimens with pure black
blotches. An adult with an additional prominent
ocellus between blotches 1 and 2 is illustrated by
Román (1981: 74).
Cichla orinocensis never shows black blotches
posterior to the pectoral-fin base as in C. ocellaris,
C. monoculus, C. kelberi, or C. pleiozona.
Juvenile and young C. orinocensis up to 60-
70 mm are similar to juvenile and young C. monoculus,
C. kelberi and C. ocellaris in colour pattern.
Both C. monoculus and C. orinocensis possess a
wide, prominent dark band connecting the bar 3
blotch and the caudal base blotch; in C. ocellaris
this band is relatively more narrow and lighter.
With increasing fish size, the caudal peduncle
band disappears in all three species, but the bar
3 blotch transforms differently: in C. orinocensis
the bar 3 blotch (like the bar 1-2 blotches) develops
into an ocellated midaxis blotch; in C. monocu-
lus and C. kelberi lateral blotches are replaced by
vertical bars which more intensely pigmented
dorsally and the caudal peduncle band disappears;
in C. ocellaris the bar 3 blotch remains as
an irregular dark blotch unlike the bar 2 and 3
blotches which are replaced by bars.
Adults of the sympatric species C. temensis
can be separated by scale counts (E1 scales 75-89
in C. orinocensis vs. 98-128), absence of lateral
ocelli, and postorbital markings wide vs. reduced
to a few small blotches in C. orinocensis. Juveniles
of C. temensis, in which scale counts are difficult
to obtain, possess a continuous lateral band vs.
distinct blotches 1 and 3, and a band caudad from
blotch 3.
Although C. orinocensis has a fairly wide distribution
including two major drainage basins,
there is no obvious geographical correlate in the
variation in morphometric or meristic characters
and the colour pattern variation cannot be organised
geographically.
A small specimen, MBUCV-V 10287, 82.3 mm
SL, from the Venezuelan part of the Rio Cuyuni
(Fig. 20), departs in colour pattern from young
C. ocellaris, possessing an ocellated blotch 1, a
large caudad tapering blotch 3, and the caudal
blotch expanded onto the caudal peduncle. This
colour pattern agrees with that illustrated by
Eigenmann (1912, pl. 69 fig. 2) of a 138 mm
specimen from Gluck Island in the Essequibo
River identified by Eigenmann as C. ocellaris.
Eigenmann’s other figures of a juvenile and two
adults of Guyanan C. ocellaris are compatible with
C. ocellaris as illustrated in this paper and in Kullander
& Nijssen (1989). The Cuyuni specimen
has 80 scales in the E1 row and lateral line sinistrally
discontinuous, dextrally continuous. Measurements
fall outside C. ocellaris in morphometric
PCA analyses. The colour pattern is more similar
to that of small C. orinocensis (cf. Fig. 13), although
the blotches may be considered large also for that
species. A photograph of a large adult Cichla
specimen, MCNG 16565, 225 mm SL, from the
Rio Cuyuni (specimen not examined; photograph
reproduced by Winemiller, 2001: fig. 1, right
center, as C. ocellaris), shows a specimen very
similar to a large specimen of C. orinocensis from
the Rio Caroní (Fig. 18). It is thus possible that a
population of C. orinocensis inhabits the upper Rio
Cuyuni and the possible presence of this species
in the Essequibo River drainage, suggested by
Eigenmann’s figure, should be investigated further.
Kullander & Ferreira: Review of Cichla