Loricariid Home Page
by Jon Armbruster
All information on the Loricariid Home Page is copyright protected by J. W. Armbruster (2001), information and photos are to be used only via consent of the author (armbrjw@auburn.edu)

Aphanotorulus ammophilus, holotype, photo by K.S. Cummings



  • The Loricariidae is the largest family of catfishes with now greater than 680 species (Reis et al. 2003). This makes the loricariids about 25% of described catfishes. The Loricariidae has been receiving a lot of attention by scientists recently, and many species are being described each year. My reasearch is on the phylogeny and taxonomy of the loricariids that are typically referred to as plecos in the pet trade. These fishes are mostly placed in the subfamily Hypostominae which has five tribes: Corymbophanini, Rhinelepini, Hypostomini, Pterygoplichthyini, and Ancistrini (which used to be recognized as its own subfamily). Together, this group has more than 450 species.

    Unfortunately all of the work that is being done in loricariids is not well supported. In the past 25 years, we have seen a dramatic increase in teh number of genera in the Loricariidae, and most of these are poorly supported. In a lot of the L-number guides you will see (L-numbers are an aquarist invention that provides a pseudo-taxonomy for loricariids) the genera assigned to particular taxa seem to be applied with out much thought. Given that most of the recent genera are so poorly described, that is not surprising that many mistakes are made. My work has tried to make some sense of the generic level taxonomy of the Hypostominae, and the bulk of my work to this time was recently published (Armbruster 2004). The taxonomy followed on these pages follows that work.

    As part of the All Catfish Species Inventory, we are attemping to describe all undescribed species of catfishes. This has given us the opportunity to provide descriptions and keys of the species of many genera. I will add these as we go.

    Welcome to my loricariid home page.  I have designed these pages to act as a means to identify the genera of the subfamilies Neoplecostominae and Hypostominae as well as an undescribed subfamily.  This encompasses a majority of the genera of Loricariidae and includes all of the genera typically sold in the aquarium trade under the name pleco or plecostomus.  The primary emphasis of these pages is on the Hypostominae (sensu Armbruster, 2004) which includes the former Ancistrinae and excludes Delturus, Hemipsilichthys, Isbrueckerichthys, Kronichthys, Pareiorhina, and Upsilodus.

    There are three different ways to search these pages.  The first is to use a key that includes all of the pertinent genera.  Any sucker-mouth, armored catfish can be entered into the key, but members of Loricariinae and Hypoptopomatinae cannot be identified beyond subfamily. Lithogenes appears to be an astroblepid and not a loricariid, but does possess armor plates and a sucker-mouth, is also in the key.  The second is to choose a subfamily, tribe, genus, or subgenus from the list of taxa page.  The third is to click on a genus on the phylogenetic tree.  The tree is based on Armbruster (2004).

    Nearly all of the pictures in the following pages can be clicked to view a larger version of the picture.  I have tried to eliminate all references to taxa names that have not yet been published, if some names have made it through, they cannot be considered accepted names and cannot be used.  If you have any comments or suggestions on these pages or find parts of the key to not work well, please contact me at armbrjw@mail.auburn.edu.

    Dekeyseria pulcher, photo by K.S. Cummings


    Ancistrinae had been recognized as a subfamily of Loricariidae since Isbrücker (1980) based on the putatively derived presence of what were commonly called evertible interopercular spines.  I prefer to call the adaptation evertible cheek plates (loricariids do not have interopercles) with associated hypertrophied (elongated) odontodes (odontodes are the integumentary or skin teeth covering the bodies of loricariids and sometimes lengthened and thickened to form spines).  Regardless, evertible cheek plates are not restricted to Ancistrinae.  The species of Pterygoplichthys also have evertible cheek plates.  Most species of Pterygoplichthys were originally described in genera now placed in Ancistrinae, but in the last 50 years, the presence of evertible cheek plates in Pterygoplichthys has been neglected.  There are several reasons for this.  The first is that juveniles do not have well-developed cheek odontodes and juveniles are more often encountered than adults.  The second reason is that the most commonly seen species are those of the P. multiradiatus group (Liposarcus sensu Weber, 1991, 1992) which do not develop hypertrophied odontodes in the evertible cheek mass even as adults.  Regan (1904); however, noted that despite the fact that members of the P. multiradiatus group do not have hypertrophied cheek odontodes, when captured, they will evert the cheek plates with the same ability as ancistrins.  Despite the ability of Pterygoplichthys to evert the cheek plates, they do lack the one other characteristic that can be used to diagnose Ancistrinae, a modified sickle- or bar-shaped opercle.  What this suggests is that  Pterygoplichthys is intermediate between other Hypostominae and Ancistrinae and that Hypostominae is made paraphyletic by the continuing recognition of Ancistrinae (see phylogeny).  This paraphyly was first suggested by Schaefer (1997), but he felt he did not have sufficient evidence to alleviate the paraphyly.  I feel that the evidence now is strong and that Ancistrinae should be returned to Hypostominae and recognized as the tribe Ancistrini.  In addition, I will be describing four new tribes that will be referred to as Corymbophanes, the Rhinelepis group, Hypostomus, and the Pterygoplichthys group in these pages.  Hemipsilichthys, Isbrueckerichthys (formerly referred to as Pareiorhaphis), Kronichthys, and Pareiorhina are placed in Neoplecostominae and a new subfamily is going to be described for Delturus + Upsilodus.

    Where are some of the genera?

    Isbrücker et al. (2001) described 14 new genera of the Loricariidae. Chockley and Armbruster (2002) were the first to sink one of the genera. 10 more were relegated to the synonymy of other genera in the Checklist of Freshwater Fishes of South and Central America (Reis et al., 2003). Two others were relegated to the synonomy of other genera by Armbruster (2004). Of the 14 genera, only Pseudolithoxus has been accepted as of Armbruster (2004).

    Why is this? Today, describing genera is a difficult thing. One must first have a phylogeny before one can properly diagnose genera. Most of the genera described in Isbrücker et al. (2001) were described without the basis of a phylogenetic analysis. Where phylogenetic analyses were refered to, these were the phylogenies of other authors and those authors did not feel that their data was strong enough to warrant the description of the genera. For some, they may actually be proven to be good in the future; however, the scientific community seems to be of the same mind that if the authors of the genera were not willing to provide the necessary evidence to recognize the genera, then why should we recognize them?


    The lesson that anyone should take from what happened to the 14 genera of Isbrücker et al. (2001) is that you shouldn't describe taxa in aquarium journals. Aquarium journals do not follow the rules that scientific journals follow. The most principle of these is peer review. Peer review means that the paper goes to other experts and the scientific quality of the paper is assessed. If the paper is not good, hopefully the filter provided by peer review will keep the paper from being published. The scientific community is forced to offer its review of the work after the paper is already published. The scientific community has been clear that Isbrücker et al. (2001) was not of the caliber that is needed in a scientific paper.

    This is not to say that there is no place for amateurs in taxonomy. Historically, taxonomy has had a lot of amateurs that have provided a lot of important work. Taxonomy is not rocket science; however, it is science, and science proceeds by rules. If you wish to be an amateur scientist, you will be held to the same level as the professionals. That means, if you want to do taxonomy, publish in a reputable scientific journal. If the paper is not peer reviewed, then it should not be published. Therefore, whenever you see new taxon descriptions in an aquarium magazine, be very skeptical. In all liklihood, it is not a good description. Editors of aquarium magazines should refuse any new taxon descriptions, or, at the minimum, make sure that professional taxonomists review the papers and that you abide by the reviewers' decisions.

    My Philosophy

    Besides that, I can say that I am more of a lumper at the genus level than many others. I would prefer to recognize large, well-diagnosed groups instead of a bunch of small, undiagnosable entities. Often, subgenera can be described and this maximizes the ability for the Linnean Taxonomic Scheme to express phylogenetic relationships. Everyone has their own opinions on what should be labeled as a genus, and these webpages express my views.

    Peckoltia vittata, photo by K.S. Cummings

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  • If you have questions or comments, please contact me at armbrjw@mail.auburn.edu.