_.-■:' \^-Jc-\ ::'' . ^:- ' " - '.:.,_ , ■ -.. 136 



taxonomic comparisons of sexually dimorphic characters (Mago-Leccia 1983, Van et 

 al. 1984, Ferraris and Fernandez 1987). 



Ferraris (1988) discussed extensively the distribution of sexually dimorphic 

 structures, and their impKcation in the systematics of doradoids. His study is the 

 most comprehensive to date, in terms of providing information for a large number 

 of species, and he considered the available information in a phylogenetic study of 

 relationships among the mcluded taxa. Detailed information was presented on the 

 external appearance and the osteology of the barbels and dorsal and anal fins 

 among a variety of taxa. A most unusual modification of the anal fin in 

 Centromochlus and allied genera led Ferraris to re-elevate that clade to separate 

 family status. While recognizing the tremendously informative value of sexually 

 dimorphic structures in evaluating relationships of these catfishes, Ferraris 

 recognized the limitations of inferring relationships based on the current state of 

 knowledge. His implication was that mature males of many taxa are needed before 

 phylogenetic relationships can be further resolved. 



Nearly all of the information about sexual dimorphism provided in the above 

 references is limited to gross morphological descriptions, including some 

 osteological features, especially of the anal fin. Very little has been published 

 concerning the soft anatomy or functional morphology of dimorphic structures, or 

 the reproductive behavior and ecology of these fishes. Aside from Ihering's (1937) 

 observations, the only other pubUshed studies in which the activity of live animals 

 was observed, in both cases made by amateur aquarists, were those of Burgess 

 (1982) on Trachycorystes insignis (= Trachefyopterus galeatiis,fide Ferraris 1988), and 

 Kopke (1986) on Ageneiosus vittatus. Both recorded and photographed copulatory 

 behavior, thus apparently confirming all previous speculation of internal fertilization 

 in these fishes. Burgess reported that females of T. galeatus laid fertilized eggs 2-4 

 weeks after spawning, but Kopke did not observe oviposition iny4. vittatus. In 

 addition to these observations, Ferraris (1988) and Curran (1989) made cursory 



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