Synodontis
schall (Bloch & Schneider, 1801)
|
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.
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.
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).
Acknowledgements: Tobias
Musschoot for his permission to use
extracts from his paper on Synodontis schall.
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.
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).
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 (editors own observation)
Unreported.
| Sexual
differences |
The males will be slimmer
than the females.
|
| Feeding |
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 |
| 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.
Neotype
: Specimen which replaces
Holotype when lost.
Synonym: Different name for the same fish.
Premaxillary: In relation to the premaxilla
(an upper jaw bone) e.g. premaxillary tooth band.
Maxillary barbels: Pertaining to the upper
jaw. (maxillary barbels)
Occipito-nuchal shield: A median bone on
the upper surface of the back of the head; pertaining to
the occiput.
Humeral process:
Bony extension of the pectoral girdle.
Fontanel:
The space(s)
between the bones on top of the skull covered by skin..
Anal Fin: The fin forward from the anal
cavity.
Dorsal fin is defined
as the medial fin on top of back.
Caudal fin is defined as the tail fin.
Pectoral fins are defined as paired lateral
fins.
Pelvic fins are defined as paired ventral
fins between the pectoral and anal fins.
|
| Etymology |
Synodontis:
Syn = together; odontis
= teeth.(fused tooth plates).
schall:
After a personal name.
|
| 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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| Photo
Credits |
Aqualog Verlag,
from the book Aqualog Photo Collection 1 and
is therefore copyright to this publication.
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| Synonyms:
|
| Silurus
schall, Hemisynodontis schall, Leiosynodontis maculosus, Pimelodus
schall, Synodontis clarias,
S.arabi, S.maculosus, S. smithii |
| Common
Name: |
| Schall's
Synodontis |
| Family: |
| Mochokidae
|
| Subfamily: |
|
| Distribution: |
| 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) |
| pH.: |
| 6.0 -8.0. |
| Donation: |
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