Hi all,
That species does appear to be Panaque maccus. It looks a little odd, though, kind of like the ones from the Rio Caroni and possibly also the Rio Caura of Venezuela.
I did indeed sink Panaquolus in the following pub:
Chockley, B. R. and J. W. Armbruster. 2002. Panaque changae, a new species of loricariid catfish (Teleostei) from eastern Peru. Ichthyological Exploration of Freshwaters 13:81-90.
The reason why I sunk Panaquolus is that the group does not significantly differ from the rest of Panaque. It is probably a monophyletic (natural) group, but I don't see any reason to recognize Panaquolus other than to be confusing. There are a few undescribed species that don't fit neatly into either group. There is one wood-eating genus in the Ancistrini and it is well-supported, why split it? At best, it could be worthy of subgenus status. There certainly was no justification in Isbrucker et al (2001) for recognizing any of the genera that they describe and the diagnoses are inadequate. The only one of those 14 genera that I am currently accepting is Pseudolithoxus because I had planned on describing the Lasiancistrus anthrax group as a new genus anyway. A secondary reason why I am not recognizing the taxa is because describing genera and adequately supporting them as monophyletic entities worthy of description is very hard work. In modern taxonomy, we need to know where the group fits into a phylogeny in order to support the description of the genus. Without such work, there is no justification for us to accept it. This sort of work was not done by Isbrucker et al. It is no longer acceptable to simply say that you think it is new therefore it is. My pub on the phylogeny of loricariids should be coming out by the end of the year or early next year. It will have some major changes to the taxonomy of loricariids. I should be updating my website sometime soon to reflect these changes.
Panaque is going to get even more confusing as time goes on. Peckoltia and Hemiancistrus (it is not possible to tell the difference between the two) grade into Panaque in much the same way that Hypostomus grades into the former Cochliodon (sunk by Weber and Montoya-Burgos, 2002). Panaque, Peckoltia, Hemiancistrus, Hypancistrus, and Parancistrus are certainly too much of a mess to be splitting right now. Further splitting just makes further problems and further confusion.
The best way to tell Panaque from Peckoltia/Hemiancistrus is by the teeth - spoon-shaped in Panaque and thin in Peckoltia, but this character often doesn't work in small specimens of Panaque. One thing that does work 100% of the time is that Panaque lacks the buccal papilla common to most loricariids. The buccal papilla looks almost like the epiglottis and is right in front of the flap inside of the mouth along the dorsal surface (called the oral or buccal valve). Interestingly, this is also the way to tell most of the Hypostomus cochliodon group (also wood-eaters) from the rest of Hypostomus (I have the character illustrated in my pub at:
http://www.mapress.com/zootaxa/2003f/z00249f.pdf ).
Sorry for the long post, but I hope it helps.