This study aimed to investigate the local and regional patterns of habitat use by piabina argentea reinhardt, 1867 in four different rivers from the velhas river basin. water velocity, depth and substrate were measured at each sampling site. ecomorphological analysis was performed using 17 ecomorphological attributes and 40 specimens from each river. although the populations overlapped in morphological space, canonical discriminant analysis showed that they were statistically different, mainly the population from the velhas river. the most important attributes in the analysis were compression index, relative body depth, and index of ventral flattening. the local patterns of habitat use were not similar between all rivers, but in general, the regional pattern was slow flowing habitat with 20 to 40 cm and 60 to 80 cm of depth and sand, silte+clay and leave banks as substrate. considering the physical characteristics of each river and the pattern of regional habitat use, a great amount of the species requirements was observed in the four rivers. nevertheless, a silted river like the velhas seems to have higher water velocity, shallower habitat and fine particle substrate, which fulfill most of the species habitat requirements.
Ecomorphology; morphological overlap; intraspecific variation; São Francisco River basin
