KARYOLOGICAL, BIOCHEMICAL, AND PHYSIOLOGICAL-ASPECTS OF CALLOPHYSUS-MACROPTERUS (SILURIFORMES, PIMELODIDAE) FROM THE SOLIMOES AND NEGRO RIVERS (CENTRAL AMAZON)

Karyological characteristics, i.e., diploid number, chromosome morphol ogy and nucleolus organizer regions (NORs), biochemical characteristic s, i.e., electrophoretic analysis of blood hemoglobin and the tissue e nzymes lactate dehydrogenase (LDH), malate dehydrogenase (MDH), alcoho l dehydrogenase (ADH), and phosphoglucose isomerase (PGI), and physiol ogical characteristics, i.e., relative concentration of hemoglobin and intraerythrocytic concentrations of organic phosphates were analyzed for the species Callophysus macropterus collected fi om Marchantaria I sland (white water system - Solimoes River) and Anavilhanas Archipelag o (black water system - Negro River). Karyological and biochemical dat a did not reveal significant differences between specimens collected a t the two sites. However, the relative distribution of hemoglobin band s I and III (I = 16.33 +/- 1.05 and III = 37.20 +/- 1.32 for Marchanta ria specimens and I = 6.33 +/- 1.32 and III = 48.05 +/- 1.55 for Anavi lhanas specimens) and levels of intraerythrocytic GTP (1.32 +/- 0.16 a nd 2.76 +/- 0.18 for Marchantaria and Anavilhanas specimens, respectiv ely), but not ATP or total phosphate, were significantly different, in dicating a physiological adaptation to the environmental conditions of these habitats. It is suggested that C. macropterus specimens from th e two collecting sites belong to a single population, and that they ad justed some physiological characteristics to adapt to local environmen tal conditions.