information about behavior or the actual mechanism of internal fertilization in 

 these fishes. Rather, he summarized in detail the prior classifications of various 

 authors, and provided a novel arrangement of twelve genera of ageneiosids and 

 auchenipterids into five families, two of which were new (Centromochlidae and 

 Asterophysidae). The main contribution of Miranda-Ribeiro's (1968b) work was his 

 recognition of the fact that sexual dimorphism represents a character that suggests a 

 relationship between auchenipterids and ageneiosids. He further indicated that the 

 classification proposed by Ihering (1937) was impractical, since it necessitated 

 confirmation of a mode of reproduction (i.e., internal versus external fertilization) 

 to accurately determine taxonomic placement. 



Britski (1972) gave additional information about sexual dimorphism in 

 various auchenipterid and ageneiosid genera. He examined the gross morphology 

 of external characters and the testes of many taxa, and speculated on the functional 

 significance of sexually dimorphic structures. Britski found what he considered to 

 be taxonomic differences in these characters, and included them in a hypothesis of 

 relationships of the auchenipterid and ageneiosid genera. He designated taxa as 

 having "incomplete" or "complete" sexual dimorphism, based on whether only a 

 partial or entire complement of dimorphism was observed involving the dorsal and 

 anal fins and barbels. Britski's was the first study to include extensive comparisons 

 of sexually dimorphic characters, in combination with many other morphological 

 features, in a broad attempt to elucidate relationships among auchenipterids and 

 ageneiosids. Nevertheless, a relatively limited amount of large series and/or 

 seasonally collected material of some species was examined, at least in terms of 

 providing unequivocal data on the presence or absence and detailed nature of 

 sexual dimorphism in nuptial males. 



In addition to the aforementioned studies, more recent descriptions of 

 species in three auchenipterid genera (Entomocorus, Epapterus, and 

 Trachefyopterichthys) were accompanied by morphological information and limited 



