119 



The ageneiosid basipterygium invariably supports seven lepidotrichia, the 

 first of which is unbranched and thicker than the remaining elements. The primitive 

 condition for siluriforms is thought to be one in which there is a small bony spUnt 

 and six functional rays (one unbranched and five branched, designated i + 5), which 

 Ferraris (1988) suggested might be a synapomorphy of all siluriforms, since other 

 otophysans generally have more branched rays; his implication was that fewer rays 

 in siluroids was derived relative to other otophysans. However, Ferraris 

 subsequently concluded that the primitive count for doradoids was i + 5 

 (Trachelyopterus, Centromochlus, and allied taxa), and that a high fin-ray count in 

 several genera was a derived state that had occurred independently. Considering all 

 catfishes, therefore, the primitive condition is a low number of fin rays (thus not a 

 synapomorphy), and the derived condition of an increase in fin rays has almost 

 certainly occurred independently in many unrelated lineages. Relative to all other 

 doradoids, the structure of the pelvic girdle and the fin-ray count of ageneiosids is 

 relatively primitive. 



The innermost ray of the ageneiosid pelvic fin has a membranous connection 

 with the skin on the belly for a substantial portion of the length of its inner branch, 

 up to half in some specimens examined. Ferraris (1988) found the same condition 

 in some species oiEpapterus, but he erroneously considered it to be apomorphic of 

 that genus only; this character may in fact represent an additional synapomorphy 

 between ageneiosids and Epapterus. Like most other genera of auchenipterids, 

 however, Epapterus has a variable and substantially greater number of pelvic rays 

 than ageneiosids (e.g., 14 to 16 in E. blohmi; Vari et al. 1984), representing a more 

 derived state. i "^'j- '^ «''■/ ' '■ \)=. *•"• 



