SUMMARY
The electrophoretic patterns of hemoglobins from Amazonian fishes have been described. The fishes include the South American lungfish, Lepidosiren paradoxa, four species of fresh water rays of the genus Potamotrygon, and actinopterygian teleosts from 77 genera of which 75% belong to the superorder Ostariophysi. For 97% of the bands the electrophoretic mobility of the fish hemoglobins was less than that of human Hb A. Lepidosiren has a single hemoglobin. Hemolysates from Potamotrygon showed blurred patterns with a mean number of 3.8 bands per phenotype. The teleosts showed a mean number of 4.0 bands per phenotype. The mean number of hemoglobin bands was different for fishes belonging to the superorders Ostariophysi (3.3 ± 0.15) and Acanthopterygii (6.7 ± 0.38). Patterns with a single hemoglobin were found in 8% of the phenotypes. Two or more hemoglobin patterns were found for about 10 species. However, taxonomic difficulties and the low number of specimens tested necessitate more studies to ascertain whether these cases represent genetic polymorphisms at the hemoglobin loci. By SDS gel electrophoresis the molecular weights of denatured hemoglobin chains from representatives of 50 genera were found to be comparable to the molecular weight of human Hb A chains. There are no obvious correlations between hemoglobin multiplicity and the fish behaviour or habitat preference. These tropical fishes have hemolysates wich are as complex as those from temperate zone fishes.