filamentosum - capapretum

[Stackdeck]

Hi everyone i just got a question about the juvenile differences between

Brachyplatystoma filamentosum

and

Brachyplatystoma capapretum

. The catelog page for capapretum says "Juveniles are marked by bold, large (twice or more times the diameter of the eye) dark brown or gray spots centred above lateral line". But when i check the pics of juvenile filamentosums on its catelog page the spots seem larger than the eye. So are the pics on the filamentosum page correct?

[Jools]

Quite possibly not. I've moved this to the bugs forum.

Jools

[MatsP]

Jools, did you mean to move it to "resolved forum"?

--
Mats

[Jools]

No, autopilot, it's in the right place (reported and not resolved).

Jools

[Martin S]

Who should look at this? Anyone specific, or do we need paperwork to confirm the differences?

[Jools]

Well, short of an ichthyologist, it would be a research job - I _think_ that text came from Gouldings Big Amazon cats book.

Jools

[Jools]

After a bit more research, the length of the barbles are the best ID feature and I now need to move some pics...

Jools

[Viktor Jarikov]

Thanks so much, Jools. This has been an unsolvable puzzle for me too.

[Viktor Jarikov]

Jools, is your statement about the barbel length

-- a product of much work and time including study of the revision that split the two species? or just a quick hunch?
-- applicable to all ages/sizes?
-- which fish got higher barbel-to-body length ratio?

This topic has been coming up and still is, especially on MFK (where Stackdeck, RedtailRob, me and others are members too). It looks like we all could really use experts' help. Necrocanis (a member here and the leader of the Catfish section on MFK) knows well and collaborates with Dr. John Lundberg and has sent him this question. See here, please: http://www.monsterfishkeepers.com/forum ... aprapretum

[Jools]

The latest data is from a keeper of both species who reports that

Brachyplatystoma capapretum

has very very long barbels. Also, over 4-50cm, they grow much faster than

Brachyplatystoma filamentosum

. The body is more slender and juveniles are differently colored and patterned and have a longer upper caudal fin lobe.

Jools

[necrocanis]

I have sent email to Dr. Lundberg who in conjunction with others was the one who split these species and reorderd Brachyplatystoma back in 2004. I am not sure if this site has access to those original docs or not. Dr. Lundberg is a very busy man as you can imagine leading the all catfish species inventory as well as his other responsibilities. It may be months before I hear back if at all on this subject.

My question is to Jools. Has the member you mention provided proof that he is indeed keeping both species and if so may we see this evidence and the basis for determining species? I feel that one member keeping a single individual of each species is questionable for data to determine species. I am not doubting said keeper's abilities, just that the inventory here is as low as it gets before you hit no inventory at all. I would like to see this confirmed with multiple members who are keeping the two before we can say for certain this is reliable. Also comes in to question that these fish differ in appearance from fry-juvie-subadult-adult within the same species. IMO we would need to verify the exact species kept before we can determine differences. Things like collection localities ect. can be useful. For instance if the collection point of the animal was in an area where the two species do not coexist. Hopefully we can come up with something good from all of this. Would be extremely interesting if the member could come show what they have.

Thank you.

[Viktor Jarikov]

Dr. John G. Lundberg gave his reply, which differs greatly from what has been considered here.

See this sister thread on MFK: http://www.monsterfishkeepers.com/forum ... etum/page4

[Jools]

Certainly looks like one that needs to be checked out - so can someone send me the 2005 paper, I'll check it out.

Cheers,

Jools

[Birger]

It is on its way.

Birger