Catfish Corner: A Major Work on Catfishes
Author: Lee Finley
I know, I know. I was trying to get away from some of the science and get back to basics, but something in the world of catfish science has come along and it just cannot be ignored. This is the publication of the “Checklist of catfishes, recent and fossil (Osteichthyes:Siluriformes) and a catalog of siluriform primary types,” by Carl J. Ferraris, Jr. (2007. Zootaxa1418: 628 pages). This massive document has been a long time in coming and has been well worth the wait. It is surely a new starting point for all catfish taxonomy to follow. One very nice thing regarding this work is that it was electronically published (as well as on paper) and is available on the Internet; it can be accessed for no charge at www.mapress.com/zootaxa.
The paper takes into account all catfish species described through 2005. There is also an annotated bibliography of catfish taxonomy for the year 2006, although none of this material is incorporated into the main body of the work. But relevant points (new genera and species) are listed in the extensive (79-page) index that is provided, thereby giving the reader access to the main points of this new material.
In all, including the 2006 material, Ferraris provides information on a total of 34 families, 467 genera, and 3117 species (I have subtracted the fossil material from his figures; overall this is certainly important, but it is not of great interest within the framework of the aquarium hobby).
The study is basically a literature-based one, and Ferraris only proposes two new names. These are one new species name (for an African clariid) and one new genus name (Pseudobagarius) for a group of 13 Asian akysid catfishes formerly placed in the genus Akysis.
The author does make specific note that this is his work and interpretations, and that it may “…not please all catfish taxonomists…” This will certainly be nothing new, and as I noted above the work is the new starting place for future discussions of catfish taxonomy.
A Few Corrections
The work is not free of errors. Please get me right here—I am not complaining, but I must make note of this. I am sure that others in the discipline of catfish taxonomy will be addressing additional topics in future works. In that Zootaxa does have a process for publishing errata, the author himself may no doubt be returning to certain areas for clarification. By no means am I a taxonomist, but I am a reader and would like to briefly point out a couple of potential problems areas:
1. Under Microsynodontis batesii Ferraris notes that “Ng (2004h:2) stated that Microsynodontis chrystyishould be treated as valid, but provided no further comments.” In fact, Ng does provide differentiating characteristics on page 44 of the referenced paper.
2. In the 2006 paper by Wright and Page, which presented a revision of the Lake Tanganyikan Synodontis catfishes (and has been covered in this column), three new species were described. Ferraris makes note of these in the 2006 literature section (and includes them in the index), but does not note that S. irsacae was removed from synonymy with S. dhonti and resurrected to species status in the paper.
I am sure that the above items (and other things, no doubt) will be addressed in due time by Ferraris and others. It is part of the flow of taxonomy—a very fluid and dynamic process. It would obviously be impossible to address all of the potential topics in the Ferraris paper which might be of interest to catfish fans.
Catfish Families Addressed by Ferraris
Ferraris notes that this family “…is arguably the most poorly resolved of any catfish family.” Lucky for us that this is one of those not-so-important aquarium families, but we do have to deal with at least one species, seemanni, and it can be seen in both aquarium and scientific literature under a variety of genus—and even species—names (Arius seemanni, Arius jordani, Ariopsis seemanni, Hexanematichthys seemanni, etc.). And…in another paper for fans of Ariidae this species is designated as Sciades seemanni. This new paper, also published in Zootaxa, is “Systematics of the family Ariidae (Ostariophysi, Siluriformes) with a redefinition of the genera,” by A. P. Marceniuk and N. A. Menezes (2007. Zootaxa, 1416: 109 pages). This paper is also available for open viewing on the Zootaxa website.
Regular readers of this column will know that I am not a big fan of Sciades seemanni as an aquarium catfish. But it is widely available and must therefore be addressed.
One other note: Carl Ferraris has at least a couple of fishes named in his honor (a loricariid catfish and a Badis species). Within the Marceniuk and Menezes paper he receives another honor: a genus named after him. This is Carlarius and it is erected to encompass four species of West African ariids.
Panaque (and Panagolus)
This popular group of loricariid catfishes is easily dividable into two groups based on size. There are currently three large species (P. nigrolineatus, etc.) and seven smaller ones (P. maccus, etc.). The largest of the “smaller” species reaches a standard length (SL) of around 14 cm. (5½ inches), but most of the species are smaller than that. In 2001 Isaac IsbrÜcker and Erwin Schraml erected the genus Panagolus to include the smaller species. This genus has not achieved total acceptance, and in various literature (both scientific and hobby) both names can be seen in common use. Ferraris has chosen to accept this genus for the smaller species as valid. I think that I can say, with confidence, that this is not the last we will hear on this topic.
Synodontis (including Hemisynodontis and Microsynodontis)
Some changes in species names are in order according to the paper. These are not “new” names in the strict sense, but are just modifications of existing names. The reason for this is to have the gender of these species names agree with the gender (masculine or feminine) of the genus name as required by The International Code of Zoological Nomenclature. Therefore, the endings of the species names must be changed for 32 species.
The situation with the affected species names is a little strange. In the three-volume “Catalog of Fishes” (William N. Eschmeyer, Editor, 1998, California Academy of Sciences: 2905 pages), the genus Synodontis was noted to be feminine, but in a listing of species names all of the spellings were as we standardly know them.
Later this catalog went into an online format. The most recent updating of this source is November 7, 2006 (last viewed 3/31/07), and the genus Synodontis is noted to be masculine. Also noted is the following: “Genus regarded as feminine in Catalog of Fishes 1998; apparently it should be masculine.”
I contacted Dr. Eschmeyer regarding this and he kindly replied that Synodontis is in fact feminine and that his “…working database has been changed.” So it would appear that in the next site update the necessary changes in the gender of the genus, and in the spelling of the species names, will appear online.
It must be noted right off that the fishes in this (these) group(s) are not very important in the hobby. Nonetheless there are a few species (especially in the erethistids), such as the so-called moth cats, that have developed a following.
There has been a fairly steady back-and-forth over the past few years regarding these two families. The gist of the situation is whether Erethistidae is really a family or just a clade (or grouping) within the family Sisoridae.
In late 2006 Alfred Thompson and Lawrence Page published a paper (Zootaxa, 1345, also available online) that diagnosed and recognized both families and provided an inventory of all the species in both. In the Ferraris paper only Sisoridae is recognized as a family and the erethistids are included therein. In that the Thompson and Page paper was published in 2006, the main concepts of it were not included in the Ferraris paper. So whether he may or may not have been convinced by the information provided in it is currently unknown.
I would like to thank both Carl Ferraris and William Eschmeyer for the providing of comments that were helpful in regarding the writing of this entry.