198 PROCEEiDINGS OF THE NATIONAL MUSEUM vol.94 



Eigenmann describes the predorsal plate of Pseudopimelodus raninus 

 (op. cit., 154) as "neariy touching the occipital process," and so it does 

 in a small specimen before me from the Rio Meta in Colombia, but the 

 premaxillaiy band of teeth has the lateral ends rounded. Unfortu- 

 nately no specimen of Pseudopimelodus raninus is now available to me 

 for studj^, and thus I am unable to determine with certainty that my 

 specimens should be referred to Pseudopimelodus. 



Eigenmann (op. cit., pp. 152, 153) describes two new species of 

 Pseudopimelodus from British Guiana. Certain features of Pseudo- 

 pimelodus albomarginatus Eigemnann (op. cit., p. 153) indicate that this 

 species is based on the young. I draw my conclusions from the large 

 series of specimens of the related form from the Maracaibo Basin, 

 because in this form the caudal fin changes with age from a deeply 

 cleft, longer, rounder upper caudal lobe than lower, in the young, to 

 then a concave caudal fin, later to a truncate one, and finally, in those 

 100 mm. to 184 mm., it is rounded or almost rounded. Thus P. 

 albomarginatus agrees with the young from the Maracaibo Basin in 

 regard to the caudal fin, and in addition it has the juvenile color pat- 

 tern, which changes to the adult color pattern at about 100 mm. of 

 length. Pseudopimelodus villosus Eigenmann (op. cit, p. 152), holotype 

 148 mm. in length, shows the rounded caudal fin and the spotted color 

 pattern found on the adults of a similar form from the Maracaibo 

 Basin. I would conclude that villosus and albomarginatus are the 

 same species if Eigenmann did not separate them in his key (op. cit., 

 p. 151) by the predorsal plate meeting the occipital process for albo- 

 marginatus. Also, he distinguishes villosus from albomarginatus by no 

 humeral spine in the former. Again, the humeral spine is reduced in 

 length with increase in size in the form from Maracaibo Basin. 



Although the status of these two species is questioned, as well as the 

 validity of the genus Aiicroglanis, it is clear that the form in the 

 Maracaibo Basin differs sufficiently from those in British Guiana to be 

 recognized as a new subspecies, which I describe below. 



KEY TO THE SUBSPECIES OF PSEUDOPIMELODUS VILLOSUS REPORTED FROM 



VENEZUELA 



la. Maxillary barbels reaching gill openings in largest specimens and much past 

 gill openings in those 150 mm. and shorter; if white blotch is present on basal 

 posterior half of dorsal fin it does not occur on more than last three inter- 

 radial membranes except very rarely as a small speck on fourth, but usually 

 much reduced in size on third from last; least depth of caudal peduncle 

 2.7 to 3.1 in the head; snout to dorsal spine base 2.4 to 2.6, head 2.8 to 3.1, 

 depth 4.8 to 5.2, in the standard length; ej'^e 3J4 to 5>^ in snout, 4 to 6 in 

 interorbital space. -Pseudopimelodus villosus butcheri, new subspecies 



1.6 Maxillary barbels not quite reaching gill openings; white blotch on basal half 

 of posterior side of dorsal fin occurring on last four interradial membranes and 

 not reduced in size on any of them; least depth of caudal peduncle 2.9 to 

 ZYz in head; snout to dorsal spine base 2>^ to 2>i, head 2% to 3.2, depth 4% 

 to 5.3, in standard length; eye 3 to 4 in snout and 5 in interorbital space. 

 Pseudopiinelodus villosus villosus Eigenmann 



