WRIGHT AND PAGE: Taxonomic revision of Lake Tanganyikan Synodontis


Museum), XI.1948, (1) S. nigromaculatus, MRAC
162214 (orig. I.D. S. zambesensis), TL 265 mm, SL 196
mm, Dundo, Luachimo River, barrage (Angola), coll.
Casalescol (Dundo Museum), 12.V.1960, (1) S.
nigromaculatus, MRAC 162215 (orig. I.D. S.
zambesensis), TL 180 mm, SL 136 mm, Cachimo,
Tuembe River, S806', E21'29' (Angola), coll. A.L.
Terreira (Dundo Museum), 22.VIII.1961, (1) S.
nigromaculatus, MRAC 149538 (orig. I.D. S.
zambesensis), TL 160 mm, SL 122 mm, Moushoshi River
near the junction with the Kofubu River (Katanga), coll.
M. Lips (don. M. Mignolet), 6.V.1963.
 Diagnosis. -Axillary pore absent; mandibular teeth
23-36; body with small spots; fin spines brown; 9-10
pectoral-fin rays; black triangles absent on all rayed fins;
eye 31.5-38.1 % of snout length; premaxillary toothpad
interrupted; secondary branches on medial mandibular
barbel absent; occipito-nuchal shield not covered by skin;
villous papillae present on skin of body; hindgut cham-
ber present; maximum TL 520 mm;
 The only species of Synodontis not endemic to
the Lake Tanganyika basin, S. melanostictus lacks the
rayed fin coloration common to almost all of its
Tanganyikan congeners, having spotted fins which com-
pletely lack black triangles at their bases. The black
triangles on the fins of S. tanganaicae may become
indistinct in large specimens and the body may have small
black spots that resemble those found in S.
melanostictus. In these cases, mandibular tooth counts
(23-36 in S. melanostictus vs. 33-49 in S. tanganaicae),
differences in eye size (31.5-38.1% of snout length in S.
melanostictus vs. 16.0-26.9% in S. tanganaicae), the
villous papillae on the skin of S. melanostictus (vs. granu-
lar in S. tanganaicae), and differences in humeral pro-
cess shape (Fig. 4) distinguish these species from one
another. Synodontis melanostictus differs from S.
dhonti in having a greater number of mandibular teeth
(23-36 vs. 22), an interrupted premaxillary toothpad (vs.
uninterrupted), and small, black spots covering the body
(vs. spots absent).
 Description. Morphometric and meristic data in
Table 9. Maximum TL 520 mm, maximum SL 425 mm.
Body compressed laterally. Predorsal profile straight
anterior to eye; slightly convex posterior to eye. Prea-
nal profile straight. Skin on body lacking vertical folds;
covered with villous papillae, not extending onto fins.
 Head depressed and broad, skin covered with small,
granular papillae. Snout with subconical margin when
viewed laterally, bluntly pointed margin when viewed
dorsally. Occipito-nuchal shield rugose, not covered with
skin; terminating posteriorly with narrow, rounded pro-
cess 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 subterminal; lips wide and papillate. Man-
dibular teeth 23-36, short, unicuspid; arranged in single
transverse row. Premaxillary toothpad interrupted; pri-
mary, secondary, and tertiary premaxillary teeth discrete;
primary premaxillary teeth in 2-3 rows; secondary pre-
maxillary teeth in 2-3 rows; tertiary premaxillary teeth
in 1-2 rows.
 Maxillary barbel with narrow basal membrane;
lacking branches or crenelations; extending at least to
the base of the pectoral fin. Lateral mandibular barbel
extending to point just short of anterior margin of pecto-
ral girdle; with 7-8 long, non-tuberculate branches; short
secondary branches present. Medial mandibular barbel
about half the length of the lateral barbel; with 4-5 pairs
of non-tuberculate branches; secondary branches
present.
 Dorsal fin 11,7; posterior margin concave. Dorsal
fin-spine long, striated, slightly curved, terminating in short
black filament; anterior margin of fin spine smooth; pos-
terior margin with small serrations distally. Pectoral fin
1,9-10; posterior margin straight. Pectoral-fin spine
roughly equal in length to dorsal-fin spine, striated, slightly
curved, terminating in a moderate length filament; ante-
rior spine margin with many fine, long, antrorse serra-
tions along anterior margin; posterior margin with large,
retrorse serrations along entire length. Adipose fin long,
well developed, margin convex. Pelvic fin i,6; located
anterior to vertical through posterior base of dorsal fin;
tip of appressed fin barely reaches base of anal fin. Anal
fin iii-v,7-9; posterior margin nearly straight; base located
ventral to first 1/3 of adipose fin. Caudal fin forked,
i,7,8,i.
 Humeral process triangular; wide at base; taper-
ing to sharp point; striated along lower half; becoming
granulous along upper margin; possessing weakly de-
veloped ridge along ventral margin; dorsal margin slightly
concave (Fig 4B). Axillary pore absent. Gut 1.3-1.6
times body length (n=2, MRAC 100515-100518). Well
developed hindgut chamber.
 Coloration in alcohol. Body grayish to cuprous
brown (Fig. 21). Belly pale. Scattered, small black spots
present, sometimes confluent. Maxillary and mandibu-
lar barbels white. Iris copper colored. Dorsal- and pec-
toral-fin spines brown, terminating in dusky filaments.
All rayed fins with small, black spots, similar to those
found on body.
 Distribution. Lake Tanganyika and its tributaries
(Fig. 22).
 Habitat. Littoral to benthic zones over shell, sand