Schilbe without adipose?

[sidguppy]

odd that I only spotted it now....

but i got a group of juvenile

Schilbe intermedius

and I just realised that none of them had any trace of an adipose!

now in the past -late 90's- I had a group of 8 Schilbe (we called em

Schilbe mystus

then), the same species, and I raised them from tiny 1.5" juvies to large 8-9" fish that showed sexual differences and the occasional spawning.

ALL of those had an adipose!
small, but clearly recognisable.

is this an on-off thing, depending on origin but within the species or are we dealing with 2 different but similar species here?

[Marc van Arc]

Did you notice that all pictures in the Clog show specimens without adipose (except for one stamp)?

[sidguppy]

i did and i find it very odd

I was used to encountering them with adipose, not without.

[Silurus]

According to the de Vos revision:

...in general [an adipose fin] is absent in West African populations and in specimens originating from the Nile but sometimes specimens with a rudimentary adipose fin turn up in those regions. In Central and East Africa on the other hand, populations without as well as with an entirely developed adipose fin occur. In several populations both morphotypes are mixed together, the adipose fin being absent or present but sometimes varying in size from a recognizable protrusion low down the back to a fully developed adipose fin.