WRIGHT AND PAGE: Taxonomic revision of Lake Tanganyikan Synodontis


petricola, and 33-49 in S. tanganaicae). Synodontis
polli further differs from S. petricola and S. lucipinnis
by having dark fin spines (vs. white in S. petricola and
S. lucipinnis). The large spots on the body distinguish
S. polli from S. dhonti, S. granulosus, S. melanostictus
and S. tanganaicae, and the black triangles at the base
of all the rayed fins further separate S. polli from S.
melanostictus and adult S. tanganaicae. Synodontis
polli is further distinguished from S. dhonti, S.
granulosus, S. melanostictus, and S. tanganaicae in
having an occipito-nuchal shield which is covered by
skin. The interrupted premaxillary toothpad further sepa-
rates S. polli from S. dhonti, S. grandiops, S.
granulosus, and S. multipunctatus, in which it is unin-
terrupted, and the presence of secondary branches on
the medial mandibular barbel further distinguishes S. polli
from S. grandiops, S. granulosus, and S.
multipunctatus. Synodontis polli differs from S.
ilebrevis in having a long gut (4.0-5.5 times TL in S.
polli vs. 0.8-1.4 times TL in S. ilebrevis) (Fig. 14, 15), a
well developed hindgut chamber (Fig. 15), deeper body
(body depth 20.2-27.0% SL in S. polli vs. 18.2-20.1%
SL in S. ilebrevis), villous papillae on the skin (vs. short,
flattened papillae in S. ilebrevis), and large, irregular,
closely spaced spots on the skin (vs. small, regular, more
widely spaced spots in S. ilebrevis).
 Description. Morphometric and meristic data in
Table 12. Maximum TL 180 mm, SL 145 mm. Body not
compressed. Predorsal profile convex. Preanal profile
slightly convex. Skin on body forming numerous verti-
cal folds covered with villous papillae which do not ex-
tend onto fins, giving skin somewhat velvety texture.
 Head deep and broad; skin covered with villous
papillae. Snout with broadly rounded margin when
viewed laterally and dorsally. Occipito-nuchal shield cov-
ered with skin, terminating posteriorly with wide, pointed
process on either side of dorsal spine, ventrally with wide,
rounded process that extends to upper margin of hu-
meral process on either side of body. Eyes dorsolateral,
ovoid, horizontal axis longer. Interorbital area flat to
slightly convex.
 Mouth inferior; lips widened and papillate. Man-
dibular teeth 40-70, short, unicuspid; arranged in 6-8 short,
transverse rows. Premaxillary toothpad interrupted;
primary, secondary and tertiary premaxillary teeth dis-
crete; numerous; arranged in 3, 2, and 1 irregular rows,
respectively.
 Maxillary barbel short; extending at least to base
of pectoral spine; lacking branches or crenelations; basal
membrane narrow. Lateral mandibular barbel extend-
ing to point just short of anterior margin of pectoral girdle;
with 4-5 short, non-tuberculate branches; lacking sec-


ondary branches. Medial mandibular barbel approxi-
mately 1/3 to 2/3 length of lateral barbel; with 3-5 pairs
of tuberculate branches; many secondary branches
present.
 Dorsal fin 11,7; posterior margin slightly concave.
Dorsal-fin spine short; striated; slightly curved, termi-
nating in short, dark filament; anterior margin of fin spine
smooth; posterior margin with small serrations distally.
Pectoral fin 1,8-9; posterior margin straight. Pectoral-
fin spine roughly equal in length to dorsal-fin spine, stri-
ated, slightly curved, terminating in short, dark filament;
anterior spine margin granulate in adult specimens; many
small, antrorse serrations along anterior margin in juve-
nile specimens; posterior margin with large, retrorse ser-
rations along entire length. Adipose fin long, well devel-
oped, margin convex. Pelvic fin i,6; located at or ante-
rior to vertical through origin of adipose fin; tip of ap-
pressed fin does not reach base of anal fin. Anal fin iii-
v,7-9; posterior margin rounded; base located at vertical
through center of adipose fin. Caudal fin i,7,8,i; forked;
lobes rounded.
 Humeral process wide; triangular; granulous; poorly
developed ridge on ventral margin; dorsal margin con-
vex; terminating in a sharp point (Fig. 5C). Axillary pore
absent. Gut long, 4.0-5.5 times TL (n = 3, MRAC 130440,
MRAC 131007-008). Well developed hindgut chamber
present (Fig. 15).
 Coloration in alcohol. Dorsum olive brown, cov-
ered with large, irregularly shaped, black spots (Figs.
15, 27). Spots proportionately larger, irregular, some-
times confluent in juvenile specimens. Belly lighter, with
smaller, irregularly shaped spots. Maxillary and man-
dibular barbels white. Iris copper colored. Dorsal and
pectoral-fin spines dark, terminating in short, dusky fila-
ments. Pectoral spine with thin, light stripe along ante-
rior margin. All rayed fins with black triangles at their
base; posterior margins white in color, becoming dusky
as specimen grows. Triangles may be completely solid
or composed of closely spaced spots. Both lobes of
caudal fin with black bar from base to tip of fin; poste-
rior margin of fin white, becoming dusky with growth.
 Distribution. Lake Tanganyika (Fig. 28); com-
mon.
 Habitat. Rocky coasts within the littoral zone, to
a maximum depth of 20 m (Matthes 1959; Coulter 1991a).
 Diet. Synodontis polli feeds on algae scraped
from rocky substrates and small invertebrates (e.g. os-
tracods, chironomid larvae, small shrimps) (Matthes
1959; Coulter 1991a).
 Reproduction. No information exists regarding
the spawning season, behavior, or habitat of this spe-
cies, although mature specimens appear to be caught at