in rays probably represents a synapomorphy among species within any given 



ingroup, including y4^ene/o5M5. 



■.■■•■ ' ■' •T_\' , -■■• ■; ■'; 



Ferraris (1988) found that the last four or five basal radials of the anal fin in 

 Auchenipterus have enlarged lamina on their ventral processes. Other doradoids 

 lack such laminar structures, although ylgene/ojT« has weak lamina, representing a 

 somewhat intermediate condition between Auchenipterus and other doradoids, 

 including Tetranematichthys (Fig. 28). This character state supports Ferraris' (1988) 

 hypothesis suggesting a close relationship between ageneiosids imd Auchenipterus. 



The first pterygiophore typically has one or two very short splints of bone and 

 one large lepidotrichium. Likewise, the last pterygiophore of the fin typically 

 supports two branched lepidotrichia, but may support from one to three. In this 

 study, all elements, regardless of size, were counted from radiographs or skeletal 

 preparations. Often the very small splints of bone associated with the anterior and 

 posteriormost pterygiophores cannot be observed externally, and their inclusion in 

 anal fin-ray counts is undesirable. In ageneiosids and auchenipterids with long anal 

 fins, future studies should include counts of anal-fin pterygiophores in order to allow 

 for uniform comparisons. . 



Ageneiosids, as well as all auchenipterids for which there are available data, 

 have unique sexual dimorphism involving a portion or all of the anal fin. The most 

 unusual morphology is found in the Centromochlidae {sensu Ferraris 1988), but a 

 review of the details of anal-fin structure in that group and other auchenipterids is 

 beyond the scope of this study. Ferraris (1988) used the structure of the anal fin 

 extensively in his phylogenetic analysis, particularly involving the CentromochUdae. 

 Unfortunately, however, there is no information available for many other 

 auchenipterid taxa. Previous Hterature was reviewed by Vari et al. (1984) and 

 Ferraris (1988). . , 



The nature of sexual dimorphism of the anal fin in ageneiosids involves only 

 the anteriormost portion of the fin, including the third through about the seventh or 



