perceived, is the presence of a single pair of mental barbels in adults, which are 

 absent in all other ageneiosids. Following its original description, the taxonomic 

 placement of v4. quadrifilis has been discordant among most authors. This has been 

 partly due to fluctuating classification schemes, inadequate hypotheses of 

 relationships among genera of the Doradidae, Auchenipteridae and Ageneiosidae, 

 and a lack of detailed information about the morphology of Tetranematichthys. 

 There is httle doubt that the presence of chin barbels provided the main rationale 

 for periodic placement of the genus outside the Ageneiosidae. 



Regan (1911) classified Tetranematichthys with most other currently 

 recognized genera of auchenipterids (in his family Doradidae), based on the shared 

 presence of a large, unencapsulated swimbladder. Eigenmann and Eigenmann 

 (1890) placed the genus within their subfamily Auchenipterinae (family Siluridae), 

 also apparently on the basis of swimbladder morphology. Giinther (1864) also 

 recognized Tetranematichthys as a distinct genus, but classified it between 

 Ageneiosus and a number of auchenipterid genera within his group Doradina, which 

 also included a number of doradids and mochokids. Miranda-Ribeiro (1911) placed 

 the genus within the Ageneiosidae. GosUne (1945) listed the genus within the 

 subfamily Auchenipterinae of the Doradidae. Fowler (1951) included 

 Tetranematichthys in his family Auchenipteridae. Based on reproductive structures, 

 Miranda-Ribeiro (1968b, posthumously) proposed a novel classification scheme in 

 which he placed the genera traditionally recognized in the Ageneiosidae and 

 Auchenipteridae into five famihes, with Tetranematichthys, Trachycoristes ( = 

 Trachycorystes) and Auchenipterichthys together in the family Trachycoristidae; 

 however, in another paper (1968c) he synonymized Tetranematichthys with 

 Trachycorystes. Most other studies have generally grouped Tetranematichthys 

 together with various auchenipterid genera. 



