56 



The prootics of ageneiosids are large elements that suture broadly with the 

 basioccipital, pterotics, and epioccipitals. They form a relatively large area of the 

 floor of the neurocranium, similar to a derived condition found in loricariids 

 (Schaeffer 1987). I have not made a detailed study of the foramina associated with 

 the auditory region. 



Homology of bones associated with the upper portion of the siluriform 

 pectoral girdle and the posterolateral region of the neurocranium has been 

 extensively discussed in the literature (e.g., Lundberg 1975, Fink and Fink 1981, 

 Schaeffer 1987). Much of the debate involves terminology of two elements: the 

 supracleithrum and the posttemporal. In most catfishes, there is fusion of certain 

 elements in this region of the skull, with the result that authors have not uniformly 

 applied the same names to homologous bones. A detailed review of the problem is 

 beyond the scope of this study. Lundberg (1975) stated that a posttemporal was 

 probably absent in all ageneiosids. However, other authors have considered the 

 bone at the posterolateral corner of the neurocranium to be a posttemporal (e.g., 

 Britski 1972, Ferraris 1988). In the absence of ontogenetic series to demonstrate 

 derivation or the extent of fusion of elements in this region, I follow Britski (1972) 

 and Ferraris (1988) in calling this bone a posttemporal. In all ageneiosids, the 

 posttemporal is a large, triangular bone extending posterolateral^ at the rear 

 margin of the neurocranium (Figs. 3-7). Anterodorsally it sutures with the 

 epioccipital and supraoccipital. 



In doradoids the epioccipitals are prominent bones that contribute to a 

 significant portion of the posterolateral dorsum of the neurocranium. This is one of 

 the characters that Regan (1911) used to unite all doradoids, and is generally 

 considered to be the most important synapomorphy uniting these taxa (Chardon 

 1968, Britski 1972, Ferraris 1988, Curran 1989). In ageneiosids, the dorsal portion 

 of the epioccipital is similar to that found in auchenipterids and doradids, where it 



m-y^:^. 



