PLECOS 101, Please!

[briggadane]

Ok, I can tell Pterygoplichthys from other plecos. But after that I have no clue on how to differentiate.

I am sure a LOT of us would like to know more.
For instance, how to tell hypan from hypo from panaque, etc.
Pictures that illustrate details would be of great help.

I can look at the catelog and find a fish, but I would love to know where to START a search.

Thanks so much, I know anyone who responds with details will be putting a lot of time into helping beginners. I know some feel that this is a wasted process, however, I for one will not dump what I learn.

I see that even experts have a hard time at the more detailed level(L066 from L333)...But if anyone has any pointers or feelings about details they can impart, that would be nice too.

[MatsP]

The general shape of the fish is one key. The pattern is often also a key (e.g. if it's mostly brown with vertical equal dark and light bands or fairly large spots, it's LIKELY to be

Peckoltia

, but can be

Panaque

too).

The next key is the size of the eye in relation to the head - large eyes usually means

Hypancistrus

, small eyes usually mean

Panaque

.

One of the best key is the mouth and the teeth: If you look at the mouth shots of for example Panaque, and compare that with for exampel Hypancistrus.

There are other keys and indications - but the above will be a good starting point to get a general idea.

I'm by no means saying it's easy, and there are some fish that look almost identical to another one in another genus.

Bristlenoses (

Ancistrus

) are easy as long as they are males, but females can be quite difficult (although colour that is dark base with lighter spots is a good key here).

And of course, once you have spotted the genus, you'll have to split it into species, and here it can get VERY hairy.

--
Mats

[racoll]

Sounds like a great idea, but I'm not sure it can be done in many cases.

Most of the characters (features that differentiate fish) are far to complicated for fishkeepers to use.

They are all listed on a key in Jon Armbruster's excellent loricariid website, but are really only of use to scientists/advanced aquarists. Here is the link.

There are a obvious features you can pick out, e.g. the

Leporacanthicus

have fimbriae (kind of wibbly curtain) on their upper lip.



The [male]

Ancistrus

are the only ones with tentacles on the heads.



Gets a bit more difficult when you get towards groups like

Peckoltia

,

Hemiancistrus

and

Baryancistrus

.

Teeth are one of the best ways of telling groups, but you need a certain amount of prior knowledge though to even make that reliable for beginners.

I think the best way is just to get experience by looking at fish and pictures of fish. Eventually you can tell most genera/common species, just by looking at them.

A web based key for common loricariid genera would be a good idea though, and with a bit of imagination it could well work. Perhaps Jools could add it to his list?

[MatsP]

I've long been thinking about having a web-based key, but it's actually quite hard to do - mostly because the official keys that exist are highly technical, and not always based on externally visible signs (although I think almost all of Armbruster's key is) - it's no good (for hobbyists) to have a key that involves killing the fish and cleaning it's bones to figure out if bone X is more than or less than 4 time longer than bone Y. [As an example, the key for Tanganyikan Syno's in the revision from 2006 requires that you look at the intestine to see if it's got a "balloon" on the hind part... Kind of difficult to do without killing the fish.]

The computer program to resolve the key is pretty trivial, so that's no big deal. But to figure out what the keys are, is not quite so easy.

--
Mats

[racoll]

But to figure out what the keys are, is not quite so easy.

That's the problem. Easy for easily diagnosable genera like Acanthicus, Leporacanthicus, Ancistrus etc.

Very hard for Peckoltia, Hemiancistrus, Baryancistrus etc.

[MatsP]

But to figure out what the keys are, is not quite so easy.

That's the problem. Easy for easily diagnosable genera like Acanthicus, Leporacanthicus, Ancistrus etc.

Very hard for Peckoltia, Hemiancistrus, Baryancistrus etc.

Exactly. And if anyone has _ANY_ ideas of how to solve this, please feel free to point it out. If nothing else, perhaps it can go in the Cat-eLog for "Genus identification" (which is only there for a few genera so far).

--
Mats

[Carp37]

Does anyone have any info as to whether all the genera are thought to be monophyletic at present (i.e. from a common ancestor, and more closely related to each other than to any fish in another genus)? I really have my doubts about the mini-Panaques (the Panaquolus-type ones like Panaque maccus) and the much larger royal-types, but that's just gut feeling based on external appearance, nothing scientific.

Within Corydoras, I'm assuming it's pretty accepted that they're paraphyletic (e.g. some Corydoras are closer to Brochis than other species of Corydoras)- I've mamaged to fail to find any info on this but know there have been a couple of talks in the last few years on the subject?

Are there any cladogram/phenogram diagrams around in the public domain for these groups?

[racoll]

Does anyone have any info as to whether all the genera are thought to be monophyletic at present

Jon Armbruster did a lot of work on this, and after synonymising a load of genera (e.g. Cochliodon, Glyptoperichthys, Liposarcus), there is now considered to be a much better, monophyletic taxonomy. Exceptions are the Peckoltia and Hemiancistrus which were not recovered as monophyletic. A lot more work will need to be done to sort these genera out.

I really have my doubts about the mini-Panaques (the Panaquolus-type ones like Panaque maccus) and the much larger royal-types, but that's just gut feeling based on external appearance, nothing scientific.

Both the large and small Panaque (including Scobinancistrus) form a monophyletic unit.

This is the reference for Armbruster's big loricariid paper:


Armbruster, J.W. (2004) Phylogenetic relationships of the suckermouth armoured catfishes (Loricariidae) with emphasis on the Hypostominae and the Ancistrinae. Zoological Journal of the Linnean Society, 141, 1–80.

Most of the information is also on his loricariid homepage.

http://www.auburn.edu/academic/science_ ... /tree.html

[Carp37]

Thanks Rupert- that's exactly what I was looking for.