154 PROCEEDINGS OF THE NATIONAL MUSEUM ^°^- ^^^ 



The relationships of the Erythrininae to other recent characids 

 remain rather obscure. They are not close to the Characinae and 

 they do not appear derived from them. A consideration of the primi- 

 tive versus specialized aspects of their skeleton may give some hint 

 regarding their relationships. In general, a reduction in number of 

 branchiostegal rays in teleosts can be considered a specialized feature 

 (Hubbs, 1919). In all probability, the presence of five branchiostegal 

 rays in the Erythrininae is relatively primitive for characids. The 

 absence of the supraorbital in both the Erythrininae and the Lebiasin- 

 inae probably is specialized and I suspect that this is also true for 

 the morphology of the antorbital in the Erythrininae. Dental 

 plates and teeth associated with the palatine, ectopterygoid, and 

 mesopterygoid in the Erythrininae is probably a primitive feature 

 in these fishes. The unique absence of a connection between the 

 dermopterotic and supraorbital laterosensory canals in the Eryth- 

 rininae probably is specialized. Whether the articulation between 

 the sphenotic and frontal in the Erythrininae is primitive or specialized 

 cannot be said. It would seem that the pectoral girdle of the Eryth- 

 rininae is rather specialized because the interosseus space, usually 

 present in teleosts and other subfamihes of characids (Starks, 1930, 

 p. 90), is absent; however, the gross morphology of the pectoral 

 girdle of the Erythi'ininae is in some respects similar to that of Amia 

 and it is possible that the form of the pectoral girdle in the Erythrin- 

 inae is rather primitive. Likewise, it is difficult to evaluate the 

 generalized (versus specialized) nature of other characters of the 

 Erythrininae. The short-based anal fin is probably primitive with 

 regard to the Characidae and Cypriniformes as a whole, and the same 

 may be true of the large scales. It is also possible that the rather 

 blunt, cylindi'ical body shape is primitive. 



Examination of the osteology of Hepseius indicates certain relation- 

 ships with Erythrinus and Hoplias. Bertmar (1959, p. 350; and in 

 litt.) has noted that Hepsetus is more primitive from the embryo- 

 logical point of view than the other ten characids he examined and 

 that all the characids he investigated are more primitive in certain 

 respects than Amia. This of course does not mean that characids 

 are more primitive than Amia, but it does pose questions about the 

 origins of the Cypriniformes. The Erythrininae appear to be more 

 primitive osteologicaUy than Hepsetus. Investigation of the ontogeny 

 of their chondrocranium should be very fruitful. 



About aU that can be concluded here is: (1) the Erythrininae are 

 definitely characid in morphology; (2) but their basic structure is 

 more remote from that of the so-called "central gi'oup of characids" 

 (i.e., the Characinae) than of any other known living characid; (3) 

 they probably were not derived from a characid ancestor that was 



