^ ■...--- ' '. \iu -■.■■: ' ■^^ : ^;-^ ;•; -•: •■■■' v. H 29 



nearly all previous references gave it generic rank. Thus, I prefer to recognize 

 Tetranematichthys as a currently monotypic genus within the Ageneiosidae. 



Status of Tvmpanopleura 



The ageneiosid genus Tympanopleura was described by Eigenmann (1912) 

 for a new species, T.piperata, from the Essequibo River at Crab Falls, British 

 Guiana (now Guyana). The distinctive features of this new genus as detailed in the 

 original description were as follows: • : . . 



Air-bladder projecting into the abdominal cavity, naked laterally, the 

 skin over it forming a large pseudo-tympanum.... This is evidently a 

 young fish. To what extent the large, protruding air-bladder and the 

 large pseudo-tympanum are characters of immaturity I am unable to 

 say. The short snout very probably is due to the age of the specimen. 



(Eigenmann 1912:203) 



Etymology of the generic name (from Latin tympanum, meaning drum, and New 

 Lsitin pleur, meaning side) was clearly based on the single putative diagnostic 

 character involving the large swimbladder. The new species was described from 

 three male and five female specimens ranging in size from 57 to 64 mm (presumably 

 TL). Although the description of T.piperata was brief, this taxon agrees in all 

 respects with other ageneiosids, i.e., in having a single pair of barbels and with fin 

 rays similar to other species of the family. My examination of the extant type 

 specimens of T.piperata do not entirely confirm Eigenmann's observations 

 suggesting immaturity, and there are additional problems with the types. 

 Unfortunately, one of the types designated by Eigenmann was not located in the 

 present study, and the holotype (FMNH 53243) and one paratype (FMNH 53244) 

 are in very poor condition. The specimens on which the description was based were 

 apparently sexually mature, insofar as the males have incipient gonopodia and long, 



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