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Abstract of Dissertation Presented to the Graduate School of the University of 

 Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of 

 ; - Philosophy 



A SYSTEMATIC REVISION OF THE 

 NEOTROPICAL CATFISH FAMILY AGENEIOSIDAE 

 '; (TELEOSTEI: OSTARIOPHYSI: SILURIFORMES) 



^ ■ -■ ' by ■ -. .,.^^...^ ■ 



; Stephen Joseph Walsh -,' .v';'" 



.: V -V.' Augustl990 / ; ;' • ■''■"'' 



Chairperson: Dr. Carter R. Gilbert ^ ,■ ■ ' '1'^ :-> 



Major Department: Zoology ." " . 



The catfish family Ageneiosidae has 12 species that inhabit most major 

 South American rivers. Their taxonomy has always been inadequately understood, 

 despite their widespread distribution and abundance. The aim of this study is to 

 stabilize the nomenclature and to examine species relationships. 



Four nominal genera are synonyms of the only two genera here recognized 

 as waiid, Tetranematichthys and Ageneiosus. >. . 



Tetranematichthys quadrifilis is widely distributed and is the most primitive 

 member of the family on the basis of features of the barbels and swimbladder. 



All other species belong to the type genus of the iaxai\y,Ageneiosus. A. 

 atronasus,A. brevis, andA.piperatus share several primitive characters, and their 

 phylogenetic relationships are unresolved. The poorly \oiowa A. piperatus occurs in 

 rivers near the Guiana Shield. A. atronasus andy4. brevis occur in the Amazon 

 basin, and each has several distinguishing autapomorphies. 



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