ack in September 2002 we highlighted
the aggressiveness of Synodontis
acanthomias
and then went on to mention its partner in crime,
Synodontis
schall, and 6 years to the day (Sept. 2008)
the spotlight now falls on this species from the Mochokidae
family.
Synodontis
schall
The original description
of S. schall is somewhat
patchy as the type speciman, which was lodged
in the ZMB (Poll 1971; Paepke 1999; Ferraris 2007),
was lost. It was originally described from the Nile
basin.
A recent paper
by Tobias Musschoot and Philippe Laleye (May 2008)
stated that they carried out a morphometric study
of 105 specimens of Synodontis schall, including
most type specimens of all nominal species considered
junior synonyms of S. schall. Two new species
S. ouemeensis and S. kogonensis
are described from the Ogun (Nigeria), Oueme (Benin)
and Mono (Togo) basins, and the Kogon and Fatala (Guinea)
basins, respectively. A neotype is designated for
S. schall. The two new species differ from
S. schall mainly by the width of the premaxillary
toothplate (12.9–24.3% HL for S. schall
vs. 21.6–32.7% HL), and can be distinguished
one from the other by differences in orbit diameter
(20.5–26.8% HL for S. ouemeensis vs.
19.4–21.0% HL for S. kogonensis) and
prepectoral length (23.4–28.2% SL for S.
ouemeensis vs. 21.6–23.3% SL for S.
kogonensis).
It is also thought
that Synodontis
robbianus is a synonym
of S. schall (Willoughby, N.G., 1994) but
more work has to be carried out in Lake Lake Kainji
on more specimens. My own thoughts are maybe not,
as I have kept S. robbianus and I did not
note any aggression what so ever with this species,
but we will find out in due course.
Synodontis
schall
There are quite
a few colour varients to this species (see colour
section below) and it depends on where a certain speciman
originates from as S. schall is one of the
few Synodontis species with a very large
geographical distribution. It is known from practically
all West African basins, except for the coastal basins
of Sierra Leone and Liberia (Paugy and Roberts 1992;
Paugy et al. 1994). The species is also known from
the Nile basin, Uebi Giuba (=Uebi Shebeli), and Lakes
Abaia, Stephanie, Turkana (=Rudolf) and Tchad (Poll
1971; Paugy et al. 1994).
Acknowledgement:Tobias Musschoot forhis
permission to useextracts from his
paper on Synodontis schall.
Africa:
Nile
basin, Abaia, Stephanie, Rudolf Lake, Tana?, Uebi
Guiba (Uebi Shebeli), Chad, Niger, Senegal,
Volta?. Also known from Guinea, Sierra Leone and Liberia.
Size
30.5cm (12¼ins)
Temp.
22-26°C
(71-79°F)
p.H.
6.0-8.0.
Characteristics
Predorsal profile more or less
straight; head subconical when viewed dorsally; snout
rounded, sometimes slightly pointed when viewed dorsally;
maxillary barbels without membrane, or with a hardly
visible membrane; gill opening from level of eye (variably
between upper and lower margin), down to level of
pectoral spine base; occipito-nuchal shield terminating
posteriorly with two usually rounded, rarely more
pointed, processes on each side of the dorsal fin;
maxillary barbels almost reaching posterior tip of
humeral process, rarely beyond, unbranched; external
mandibular barbels with filaments, reaching base of
pectoral fin; internal mandibular barbels with short
filaments, reaching a vertical from anterior, sometimes
posterior, margin of eye; anterior nostrils tubular
with small lateral flap, posterior nostrils with flap
along anterior margin; eye superolateral; orbit with
free margin; mouth inferior; teeth unicuspid; 18–32
mandibular teeth; humeral process usually without
ridge along the ventral margin, upper margin straight
or a little concave, lower margin straight or a little
convex; proximal part of lateral line positioned above
mid-lateral line; anterior side of dorsal spine smooth
or with some very fine serrations proximally and with
some larger serrations distally, posterior side clearly
serrated, mainly distally; dorsal fin spine slightly
curved backwards; adipose fin height very variable;
adipose fin well developed with a convex, sometimes
rather straight, margin with a variable slope; caudal
fin deeply forked, upper lobe a little longer than
lower; anterior side of pectoral spine with fine serrations
proximally, becoming a little larger distally, but
often none at the tip, directed outwards, posterior
side with less but marked serrations along its entire
side, which are directed towards the body; pelvic
fins inserted at the level of the adipose fin origin
or a little before, posterior margin usually straight,
not or barely reaching anal fin base; anal fin reaching
beyond a vertical through the posterior margin of
adipose fin; urogenital pore and vent positioned at
the level of the adipose fin origin or a little beyond.
Colouration
Variable; generally body brown
or grey dorsally, becoming lighter on the flanks,
belly light brown or grey or whitish (specimens from
Agneby River dark grey, those from Benue River dark
brown, with lighter belly); humeral spot present;
barbels either whitish or brown, including filaments;
adipose, dorsal and caudal fin more or less the same
colour as dorsal body surface; pectoral, pelvic and
anal fins whitish or grey or brown, usually depending
on body color, sometimes relatively dark (specimens
from Agneby River). Smallest specimens (around 50mm
SL): small dark spots (,1 mm) all over body, except
ventrally but including all fins (except sometimes
the pelvic fins); sometimes marbly or mottled on body
or with some larger irregular pale spots; sometimes
with larger dark spots (.1 mm) on adipose, dorsal
and caudal fins. Larger specimens (below about 100mm
SL): variably with or without small dark spots (,1
mm), mainly on dorsal body surface and flanks above
lateral line, including the adipose fin; usually disappear
in specimens larger than about 100mm SL, but still
present on some specimens from Senegal (Rivers Gorom
and Lampsar), Uganda (Lake Albert) and Black Volta
(in the latter they also occur below the lateral line).
Aquarium
Care & Compatibility
A very robust fish and would
need to be housed with large companions who will be
able to look after themselves. Even large Pleco's
will suffer by this species (authors own observation).
Reproduction
Unreported.
Sexual
Differences
Not known, but
the females are deeper bodied than the males.
Diet
Anything and everything!. Meaty
foods are relished. Will also eat any foods given
to your other tank inhabitants and will also take
flakefood that floats to the botom. Feed also tablet
foods and frozen bloodworm which they find a favourite.
Glossary
of Terms
Anal
Fin:The fin forward from
the anal cavity. Caudal fin: Defined as the tail fin.
Dorsal fin: Defined as the medial fin
on top of back. Fontanel:The space(s)
between the bones on top of the skull covered by skin.
Humeral process: Bony
extension of the pectoral girdle.
Maxillary
barbels: Pertaining to the upper jaw (maxillary
barbels).
Neotype:Specimen which replaces Holotype
when lost.
Occipito-nuchal
shield: A median bone on the upper surface
of the back of the head; pertaining to the occiput.
Pectoral fins: Defined as paired lateral
fins. Pelvic fins: Defined as paired ventral
fins between the pectoral and anal fins. Premaxillary:
In relation to the premaxilla (an upper jaw bone) e.g.
premaxillary tooth band.
Synonym:
Different name for the same fish.
Type specimen: The species of a genus
with which the generic name is permanently associated;
the description of a genus is based primarily on its
type species, being modified and expanded by the features
of other included species.
Etymology
Synodontis:
From the Greek syn, meaning together, and odontos,
meaning tooth; in reference to the closely-spaced
lower jaw teeth. schall: Derived
from the northern Egyptian arabic dialect name of
this fish, shâl, written with "sch"
because Bloch & Schneider were German speaking
biologists.
References
Musschoot,
T. and P. Lalèyè, 2008 Designation
of a neotype for Synodontis schall (Bloch and Schneider,
1801) and description of two new species of Synodontis
(Siluriformes: Mochokidae). Journal of Natural History
42(17-18):1303 1331). Willoughby, N.G., 1994. The taxonomy
of the genus Synodontis (Pisces: Siluroidea) in Lake
Kainji, Nigeria. African Journal of Tropical Hydrobiology
and Fisheries, 5(25):25-30.
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