WRIGHT AND PAGE: Taxonomic revision of Lake Tanganyikan Synodontis


 Synodontis dhonti Boulenger, 1917
 (Figs. 5A, 6, 7; Tables 1, 3)

Synodontis dhonti Boulenger, 1917:367, description,
 Kilewa Bay, Lake Tanganyika; 1920:42, description,
 Kilewa Bay, Lake Tanganyika. Worthington and
 Ricardo, 1936:1067, 1077, 1101, note, Lake
 Tanganyika. Poll, 1946:221, figs. 21, 22, descrip-
 tion, Kilewa Bay, Lake Tanganyika; 1971:364, figs.
 168 and 169, pls. VI.6, XI.19. Matthes, 1962:37,
 fig. a, pl. 3, description, diet, Lake Tanganyika.
 Material Examined.- Holotype, MRAC 14344, TL
395 mm, SL 325 mm, Lake Tanganyika, Kilewa, coll.
Stappers, 18.V.1912.
 Diagnosis. -Axillary pore present, large; mandibu-
lar teeth 22; body lacking spots; fin spines brown; 8 pec-
toral-fin rays; black patches at base of rayed fins present;
eye 23.1% snout length; premaxillary toothpad uninter-
rupted; secondary branches on medial mandibular bar-
bel present; occipito-nuchal shield not covered with skin;
granular papillae present on skin of body; maximum TL
395 mm.
 Synodontis dhonti can be distinguished from S.
ilebrevis, S. irsacae, S. lucipinnis, S. melanostictus,
and S. polli by the presence of an axillary pore, an unin-
terrupted premaxillary toothpad, and a smaller eye
(23.1% of snout length vs. 26.0-33.4% in S. ilebrevis,
28.7-43.7% in S. irsacae, 25.2-35.8 % in S. lucipinnis,
31.5-38.1% in S. melanostictus, and 25.8-39.3% in S.
polli). Synodontis dhonti is separated from S.
granulosus, S. ilebrevis, S. lucipinnis, S.
melanostictus, S. petricola, S. polli, and S.
tanganaicae by having a smaller number of mandibular
teeth (22 vs. 50-66 in S. ilebrevis, 28-51 in S.
granulosus, 35-51 in S. lucipinnis, 23-36 in S.
melanostictus, 31-50 in S. petricola, 40-70 in S. polli,
and 33-49 in S. tanganaicae). The presence of sec-
ondary branches on the medial mandibular barbel and a
smaller eye (23.1% of snout length vs. 64.2-81.0% in S.
grandiops, 31.2-50.2% in S. granulosus, and 44.9-
62.0% in S. multipunctatus) differentiates S. dhonti
from S. grandiops, S. granulosus, and S.
multipunctatus. Synodontis dhonti differs further from
S. grandiops, S. irsacae, S. lucipinnis, S.
multipunctatus, and S. petricola in having granular
papillae on the body (vs. papillae absent). Brown fin
spines further distinguish S. dhonti from S. lucipinnis
and S. petricola, in which they are white. A lack of
spots on the body and an elevated number (n=25) of
elongated gill rakers distinguishes S. dhonti from all other
Tanganyikan Synodontis with the exception of adult S.
tanganaicae. Synodontis dhonti can be further dis-


tinguished from S. tanganaicae by having a poorly de-
veloped adipose fin (vs. well developed) and an uninter-
rupted premaxillary toothpad (vs. interrupted in S.
tanganaicae).
 Description. Morphometric and meristic data in
Table 3. Maximum TL 395 mm, SL 325 mm. Body not
compressed. Predorsal profile straight, interrupted by
convex ridge formed by orbit of eye. Preanal profile
convex. Skin on body forming numerous vertical folds
covered with granular papillae extending onto all fins.
 Head slightly depressed and broad; skin covered
with granular papillae. Snout with bluntly rounded mar-
gin when viewed laterally and dorsally. Anterior nostrils
tubular; posterior nostrils with semicircular flaps of skin
along anterior margin. Occipito-nuchal shield rugose,
not covered with skin; terminating posteriorly with nar-
row, rounded process on either side of dorsal spine; ven-
trally with narrow, bluntly pointed process that extends
to upper margin of humeral process on either side of
body. Eye located dorsolaterally; ovoid; horizontal axis
longer. Interorbital area flat.
 Mouth subterminal; lips wide and papillate. Man-
dibular teeth 22, unicuspid; arranged in single transverse
row. Premaxillary toothpad uninterrupted; primary, sec-
ondary and tertiary premaxillary teeth discrete; numer-
ous; arranged in 4, 5, and 1 irregular rows, respectively.
 Maxillary barbel with narrow basal membrane;
lacking branches or crenelations; extending at least to
base of pectoral fin. Lateral mandibular barbel extend-
ing to point just short of anterior margin of pectoral girdle,
with 4-5 non-tuberculate branches; lacking secondary
branches. Medial mandibular barbel about 1/2 length of
lateral barbel; with 2 pairs of tuberculate branches; sec-
ondary branches present.
 Dorsal fin 11,7; posterior margin straight. Dorsal-
fin spine long, striated, nearly straight, terminating in short,
dark filament; anterior margin smooth; posterior margin
with small serrations distally. Pectoral fin 1,8; posterior
margin straight. Pectoral-fin spine roughly equal in length
to dorsal-fin spine, striated, slightly curved, terminating
in short, dark filament; anterior spine margin granulous;
posterior margin with large retrorse serrations along
entire length. Adipose fin poorly developed, margin con-
vex. Pelvic fin i,6; located at vertical through posterior
base of dorsal fin; tip of appressed fin barely reaches
base of anal fin. Anal fin v,8; posterior margin rounded;
base located ventral to adipose fin. Caudal fin i,7,8,i;
forked; lobes pointed.
 Humeral process narrow, elongated, granulous;
possessing distinct ridge on ventral margin; dorsal mar-
gin concave; terminating in blunted point (Fig. 5a). Large
axillary pore just ventral to humeral process.