132 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ue 



nostomatinae. There are three important errors in Eigenmann's 

 concept of this subfamily's morphology. Teeth are present in the 

 maxillary, not absent; the gill membranes are joined to each other 

 but free from the isthmus, not slightly united; and the parietal 

 fontanel is absent, not present as Eigenmann indicated. 



Regan (1911, p. 21) placed the genera Nannostomus and Characidium 

 in the Nannostominae and included this subfamily in his family 

 Hemiodontidae. This family consisted only of his Hemidontinae 

 and Nannostominae. 



Cockerell (1914, p. 98-99), in a study of characid scales, noted the 

 close resemblance of the scales of Nannostomus and Pyrrhulina and, 

 on this basis alone, found reason to more closely associate Pyrrhulina 

 with Nannostomus than Poecilobrycon with Nannostomus. He also 

 noted the very different structure of the scales of Characidium. I 

 find that the scales of Poecilobrycon and Nannostomus are much alike 

 and, in addition, are very similar to those of Pyrrhulina, Copella, 

 and Copeina. In confirmation of part of CockerelPs work, however, 

 the osteology and scales of CJiaracidium differ quite widely from the 

 osteology and scales of any of the other genera discussed here. 



Gregory and Conrad (1938, pp. 324, 344-347) followed Regan 

 (1911) in relating Nannostomus Si.nd Poecilobrycon to Hemiodus smd 

 its relatives. They placed Nannostomus and Poecilobrycon in a sub- 

 family (Hemiodontinae) considered by them to be widely separated 

 from the subfamily (Characinae) containing Pyrrhulina. As shown 

 below, my work indicates that Nannostomus, Poecilobrycon, and 

 Pyrrhulina are related rather closely and are placed in the tribe 

 Pyrrhulinini. 



Fowler (1950, pp. 253-263) considered the genera Characidium, 

 Microcharax, Nannostomus, Archicheir, and Poecilobrycon as con- 

 stituting the subfamily Nannostominae (apparently following Eigen- 

 mann, he spelled it Nannostomatinae) . He placed this subfamily 

 nearest his subfamilies Leporininae and Parodontinae but did not 

 comment on relationships or define his groups. 



Hoedeman (1950a, p. 14) established the tribe Nannostomini to 

 include the genera Nannostomus, Poecilobrycon, and his newly pro- 

 posed N annobrycon. He apparently did not consider that the genus 

 Archicheir belonged to his Nannostomini, for he excluded it from his 

 treatment. 



In his first paper on Nannostomus and relatives, Hoedeman (1950a, 

 p. 11) considered his Nannostomini to be related to the Hemiodon- 

 tinae; however, he excluded Characidium from relationship with the 

 Hemiodontinae. He presented no evidence for this opinion. Hoede- 

 man (1954a, p. 83) reconsidered his classification and placed the tribe 

 (emended to Nannostomidi) in his family Erythrinidae, a family he 



