'common' pleco?

[Jeox]

Does anyone know what this guy is?
He has almost a greenish tint to him, and can suck onto things out of water better than any plec I've ever dealt with.

[racoll]

It's not a "common pleco" as in

Pterygoplichthys pardalis

. It looks more like

Hypostomus plecostomoides

, or similar.

Pretty much any nondescript, large, and brown pleco can be called a "common" though, and these are usually either a

Pterygoplichthys

or

Hypostomus

spp.

[Jeox]

It's not a "common pleco" as in

Pterygoplichthys pardalis

. It looks more like

Hypostomus plecostomoides

, or similar.

Pretty much any nondescript, large, and brown pleco can be called a "common" though, and these are usually either a

Pterygoplichthys

or

Hypostomus

spp.

Ooh, that looks pretty close.
Just got an in tank shot as well.

[racoll]

Without knowing which country it was exported from, it's hard to say for sure (many others look very similar), but

Hypostomus plecostomoides

does crop up from time to time.

He's a nice looking fish, and won't grow as big as the usual "commons".

[Suckermouth]

Well it's certainly a Hypostomus, but I can't tell you which one it is. However, I can tell you it ain't H. plecostomoides. H. plecostomoides is one of the H. cochliodon group species, which means few and (usually) spoon-shaped teeth, and acute-angled lower jaws. We can plainly see the lack of these characteristics in the shot of the suckermouth; it has typical tiny Hypostomus teeth, and lots of them, and the dentary angle is far greater than 90 degrees.

[racoll]

Well it's certainly a Hypostomus, but I can't tell you which one it is. However, I can tell you it ain't H. plecostomoides. H. plecostomoides is one of the H. cochliodon group species, which means few and (usually) spoon-shaped teeth, and acute-angled lower jaws. We can plainly see the lack of these characteristics in the shot of the suckermouth; it has typical tiny Hypostomus teeth, and lots of them, and the dentary angle is far greater than 90 degrees.

Well spotted!

[Shane]

This is

Hypostomus plecostomus

. They can be very difficult to distinguish as juveniles from H. plecostomoides as the coloration is nearly identical (which makes a lot of sense as their natural ranges/habitats overlap).

-Shane

[racoll]

This is Hypostomus plecostomus.

I was going to suggest this species, but wasn't sure if it's distribution extended into areas collected for the hobby (e.g. the Llanos of Colombia).

I guess from having a closer look at the cat-elog page, that they are?

[Shane]

I guess from having a closer look at the cat-elog page, that they are?

You would have to ask a hard question

Linnaeus, 1758 described H. plecostomus from "India." It was later "fixed" to Surinam, but if you (like me) think Linnaeus meant "Indies," his type could have been from any one of several Caribbean localities. Suriname was fixed by Boeseman who was doing a lot of work with loricariids in Surinam in the late 1960s. I can not say however if fixing the holotype was a brilliant link to Linnaeus' work of 210 years earlier or not. It strikes me as very coincidental that a Dutch scientist working in a Dutch colony just happened to connect his catch to Linnaeus' original description. An amazing connection since he did not have much, if any, material from other Caribbean locations to compare to Linnaeus' original description. I have never looked at Linnaeus' original description, but my guess is that it could be just as easily "fixed" to a half dozen valid spp. as it could to Boeseman's fish.

So H. pleco either ranges throughout the Essequibo, Orinoco, and coastal Venezuelan systems (i.e. the Tuy drainage and others) or it is an Essequibo drainage fish and the Hypostomus found all over the Orinoco is an undescribed fish, as might be the Venezuelan coastal population(s).

The only specimens I am aware of in the hobby currently come in from collectors near Villavicencio, Colombia (and these are what we are calling H. pleco in the Cat-elog). These are not common shipments however as it is hard to undercut the "common pleco" breeders in Florida and the Far East on prices and very few hobbyists appreciate the difference.

The Orinoco population has a huge range, but is far more numerous in the north and west in white water rivers that are closer to the Andes and have a bit more current. Further out in the llanos, as the ground flattens, they become less common, and by the Orinoco itself, are uncommon by comparison. These lower and slower reaches of the rivers are where we start finding the woodeater H. cochliodon as well as Panaque nigrolineatus. I always assumed this was because wood in these areas has longer to soak and develop a thick biofilm without being washed away every time it rains. Areas where the two spp overlap is much more of a broad transitional zone than a clear demarcation. I expect it expands, contracts, moves up river or down, etc depending on season, weather and available foods. These ebbs and flows, over a very long time, probably allowed H. pleco to colonize the huge number of Orinoco feeder systems where it can now be found.

Similar zones occur, for example between Corydoras venezuelanus and C. concolor as well as Apistogramma spp but I never understood them as well.

-Shane

[racoll]

Great info as always Shane.

Is it worth referring to H. plecostomus as H. cf. plecostomus to reflect this ID uncertainty of the Colombian/Venezuelan species?

[Shane]

Is it worth referring to H. plecostomus as H. cf. plecostomus to reflect this ID uncertainty of the Colombian/Venezuelan species?

I think a very good argument to do that could be made, but it would be counter the the currently accepted definition and range of this spp.
Unfortunately things like this happen all the time. Take a look at the C. milesi thread in Site Suggestions. C. milesi was described from Honda, Colombia (Rio Magdalena) but a latter author (Schultz) found some gray w/ black spots Chaetostoma in Venezuela and declared them C. milesi as well based on their color pattern. Now we have a huge geographic area with a half dozen (or more) different gray w/ black spots Chaetostoma spp, but they are all "technically" C. milesi until someone describes them all and countermands Schultz' identification.
-Shane

[racoll]

but they are all "technically" C. milesi until someone describes them all and countermands Schultz' identification.

While I don't think PC should create its own taxonomy, there is nothing wrong with taking a conservative approach in light of recent advances in systematics.

This for me, means that we are skilled enough bunch to realise that in all likelihood, examples like this probably constitute a complex of similar species. Restricting a species name to its described drainage is just common sense.

Disputing the findings of a study published nowadays is probably not a good idea, but one carried out 50 years ago under possibly erroneous assumptions, I don't have a too big a problem with.

However, in the case of H. plecostomus, we don't know a lot about what the species looks like through the rest of the range.

[Shane]

While I don't think PC should create its own taxonomy, there is nothing wrong with taking a conservative approach in light of recent advances in systematics.

PC has already done that on varying levels and for different reasons with different genera and spp. Schultz' fish he identified in Venezuela as C. milesi is in the Cat-elog as

Chaetostoma aff_milesi

. It just gets too confusing sometimes when the cat-elog has pictures of what are clearly different spp under one name. Even if doing so is "scientifically" correct.

-Shane

[Jeox]

Thanks guys

Glad to know he isn't going to get enormous. I was in the store debating getting him for the longest time, just because I don't really have room for a 2 foot pleco. aha