considered the reduction of infraorbital bones to four to be derived within the 

 ageneiosid clade; however, as discussed in the text, this character is variable and not 

 diagnostic of the family. In addition to the above character states, ageneiosids have 

 extremely cancellous bones of the head and fin skeletons, which represents a 

 derived condition not found in any of the outgroups that I have examined. 



Within the family, monophyly oiAgeneiosus (node B on Fig. 35) is supported 

 by two unequivocal characters: absence of mental barbels in adults (21), and dorsal 

 margin of the maxillary barbel of nuptial males with enlarged, tooth-like odontodes 

 formed by outgrowths of the maxillae (22). Eleven valid species are recognized in 

 this clade (Fig. 35). 



Tetranematichthys has all of the character states synapomorphic for the 

 family, but adults of this genus have a diminutive pair of mental barbels, and males 

 have elongate, untoothed maxillary barbels; both of these characters are 

 plesiomorphic for the family (although reduction in size of the mental barbels can 

 be considered derived relative to auchenipterids). Thus, Tetranematichthys ,, 

 quadrifilis is the sister spedcs of Ageneiosus. \ ; ' ,, - J^;- 



Three distinctive clades exist vAthin Ageneiosus, but relationships among ^ ^ 

 several of the species remain unresolved. The most derived species are^l. brevifilis 

 and A. marmoratus (node J on Fig. 35). Both species share the uniquely derived 

 truncate caudal fin, with 8+10 principal fin rays (25), and the first pectoral-fin 

 lepidotrichium not forming a stiffened, serrated spine. These two species are 

 identical in nearly all respects except coloration, and their present specific status is 

 tenuous (see comments under species accounts). Tetranematichthys and several 

 auchenipterids, including Trachefyopterus, have a truncate caudal fin, with the 

 derived condition of an additional lower principal ray. The shared presence of this 

 derived character state is considered to be the result of parallel evolution (Ferraris 

 1988). The sister species of A. brevifilis and^l. marmoratus is A. pofystictus, which 



