ANATOMICAL DESCRIPTION AND COMPARISONS 



There have been a moderate number of comparative reviews deaUng 

 exclusively with single-character complexes of siluriform morphology. These 

 include those of the pectoral girdle (Tilak 1963, Gosline 1977), the pelvic girdle 

 (Shelden 1937), the caudal fin (Lundberg and Baskin 1969), the Weberian 

 apparatus and associated structures of the swimbladder (Bridge and Haddon 1894, 

 Alexander 1964, Chardon 1968), the posterior cranial and superior pectoral 

 osteology (Lundberg 1975), functional morphology of the jaw (Gosline 1975), and 

 myology and osteology of the dorsal fin (Royero 1987). Many recent evolutionary 

 studies of neotropical catfishes have dealt with a diversity of morphological 

 characters among closely related taxa, and included fairly broad taxonomic 

 comparisons with outgroups (e.g., Baskin 1973, Howes 1983, Lundberg and McDade 

 1986, Stewart 1986, Vari and Ortega 1986, Arratia 1987, Schaeffer 1987, Stewart 

 and Pavhk 1985, and Ferraris 1988). There have been relatively few comprehensive 

 reviews of a broad suite of characters among a wide variety of taxa, the most 

 commonly cited of which are those of Regan (1911) and Alexander (1965). Some 

 studies of higher ostariophysan relationships have provided useful morphological 

 data of a limited number of catfish groups (e.g.. Greenwood et al. 1966, Roberts 

 1973, Fink and Fink 1981). ^ .: . : 



"• The above sources, along with many studies more restricted in scope, provide 

 a basis on which neotropical catfish systematists have been able to infer assumptions 

 regarding character polarities and homoplasies, and to make other morphological 

 comparisons among the diverse taxa involved. However, detailed anatomical 



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