the neotropical doradoids (Britski 1972). I have not examined Higuchi's 

 dissertation, but the remaining studies have been used extensively in my character 

 analysis and inferences about higher systematic relationships. Statements of 

 relationships outside of the Ageneiosidae are based principally on these and other 

 studies, and I make no attempt to provide additional hypotheses of interfamilial 

 relationships. However, in the following discussion, I do provided some of my 

 objections or disagreements to certain conclusions of the above authors, based on 

 conflicting information or personal observations. ^ . 



^;' Suprafamili al Relationships of Doradoid Catfishes 



As summarized in the introduction, there has been a long history of studies 

 that have suggested a taxonomic relationship between the Doradidae, 

 Auchenipteridae, and Ageneiosidae. Early classifications were largely typological, 

 and often excluded related taxa from this assemblage, or included members of other 

 unrelated families. Regan (1911) studied the osteology of a diversity of siluroids, 

 and was the first to propose relationships based at least in part on putatively derived 

 structures. His interpretation of primitive versus derived characters was 

 questionable in certain cases, however, and some of his family designations were 

 more inclusive than presently recognized. Regan placed all neotropical doradoids 

 known at the time into one family, the Doradidae, but he arranged the various 

 genera in a taxonomic key roughly corresponding to the presently delimited families. 

 In spite of the shortcomings of Regan's monograph, his study was a template on 

 which most subsequent classifications of siluroids were based. 



V As diagnosed by Regan (1911), neotropical doradoids share a number of 

 characters that, in combination, separate them from nearly all other catfishes. The 

 most important characters cited by Regan as defining for the doradoids were the 



