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(Ferraris 1988). At least some auchenipterids have a more extensively branched 

 lateral line, consisting of dorsal and ventral rows of neuromasts over most of the 

 tnmk musculature, but this presumably further-derived condition is absent in 

 ageneiosids and closely related auchenipterids (Ferraris 1988). Hypophthalmus, 

 some pimelodids, and various Old World catfishes have similar ramified lateral 

 lines, indicating that this character state has evolved mdependently several times. 



Splanchnocranium 

 Qromandibular Region 



The jaws of ageneiosids are large and heavily toothed. The premaxillae are 

 typically expanded at the midhne and tapered near the rictus, and bear numerous 

 sharp, retrorse, setif orm teeth, la. A. atronasus, A . brevis, A . piperatus, and T. 

 quadrifilis, however, the premaxillary tooth patch is relatively thin and the teeth are 

 notably weaker and fewer than in larger species. In A. ucayalensis, and, to a lesser 

 extent in the other large species, the premaxillae are moderately to extremely 

 recurved, and bear proportionally more teeth on their ventral surface, especially at 

 the midline. The dentary of ageneiosids is relatively broad, club-shaped and 

 produced anteriorly, with heavy dentition similar to the premaxilla. Expansion of 

 the anterior dentary margin was considered by Ferraris (1988) to be a 

 synapomorphy of the ageneiosid clade. The anguloarticular is relatively elongate 

 and triangular, with a greatly expanded coronoid process. There is an extensive 

 block of cartilage between the dentary and anguloarticular, with an ascending 

 process extending above the lower margin of the premaxillae when the mouth is 

 closed. The relatively large oral gape and expanded tooth-bearing surfaces in 



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