,,-_-: ,-. y. / : '■' -•;■ 152 



combination of other characters listed by Regan (1911) is unique to these three 

 families (although, individually, several of the characters are plesiomorphic and/or 

 homoplasious with respect to all other catfishes). Britski (1972) and Ferraris (1988) 

 presented additional shared, derived characters that support monophyly of the 

 neotropical doradoids. 



Royero (1987) found four characters of the dorsal fin that further supports 

 the idea that mochokids may be related to the neotropical doradoids. Ferraris 

 (1988) also found some characters shared among these taxa, but he deferred 

 suggesting a close phylogenetic relationship pending more detailed anatomical 

 comparisons. I agree with the reservations expressed by Ferraris; the state of 

 knowledge about possible relationships of all of the famiUes listed above, excluding 

 the neotropical doradoids, is insufficient at present to conclusively identify a sister 

 group of the neotropical doradoids. ^i; <•'''"''•; r, 



, . Relationships of neotropical doradoid families have been much less 



contested than relationships among the other families listed above. Most species of 

 the Doradidae are highly distinctive and not easily mistaken for any other family. 

 Numerous similarities between ageneiosids and auchenipterids have been used to 

 suggest a relationship between them, especially their shared sexual dimorphism (see 

 introduction and anatomical descriptions for additional details). The historically 

 long distinction between ageneiosids and auchenipterids was challenged by Ferraris 

 (1988), who felt tiiat differences between these two famiUes overshadowed 

 similarities between the ageneiosids and a restricted clade within the 

 Auchenipteridae, and he found that some auchenipterid genera are more distantiy 

 related to each other than one group is to ageneiosids, as discussed below. 



Curran (1989) asserted that doradids and auchenipterids are sister taxa on 

 the basis of five putative synapomorphies. He placed great weight on these shared 

 character states in rejecting any consideration of ageneiosids as the closest relatives 



wm 



