artemia IS A SMALL CREATURE THAT ADAPTS TO LIFE IN SALINE WATERS AND GROWS AND MULTIPLIES IN SUCH ENVIRONMENTS BECAUSE OF THE ABSENCE OF PREDATORS AND RIVALS. THE MOST IMPORTANT HABITAT OF artemia IN IRAN IS LAKE URMIA, AND artemia IN THIS LAKE IS NAMED ACCORDING TO ITS SPECIFIC CHARACTERISTICS AS artemia urmiana. FOR STRUCTURAL STUDIES, FIXATION WAS PERFORMED WITH GLUTARALDEHYDE AND TETRAOXIDE. THE SAMPLES WERE DEWATERED WITH DIFFERENT PERCENTAGES OF ETHANOL AND PUT INTO THE RESIN. THE SPECIMENS WERE CUT TO 70-80 NM AFTER POLYMERIZATION. THE CUTS WERE MADE ON 200 MESH COPPER GRADES AND WERE STAINED IN TWO STEPS USING URANYLACETATE SATURATED SOLUTION IN ALCOHOL AND A LEADCITRATE SOLUTION THEN WERE OBSERVED AND PHOTOGRAPHED WITH ELECTRON MICROSCOPE. FOR GENETIC STUDIES, EXTRACTION OF NUCLEIC ACIDS FROM THE SAMPLES WAS PERFORMED USING PHENOL-CHLOROFORM METHOD, AND THE AMPLIFICATION OF THE REGION OF THE RIBOSOMAL GENE OF artemia MITOCHONDRIAL GENOME WAS DONE USING PRIMER AND PCR TECHNIQUE. TO FIND THE GENETIC POLYMORPHISM IN THE SAMPLES, THE PCR PRODUCT WAS DIGESTED WITH 10 ENZYMES. THE RESULTS OF THE STUDY INDICATE STRUCTURAL DIFFERENCE BETWEEN artemia CYSTS OF LAKE URMIA IN TERMS OF THE THICKNESS OF THE ALVEOLAR LAYER AND THE FIBER LAYER, WHICH CAN BE ATTRIBUTED TO THE DEPTH OF THE CYSTS AND INDICATES THE PRESENCE OF DIFFERENT MORPHOLOGICAL POPULATIONS OF artemia URIMIANA IN THE LAKE. ALSO, IN THIS STUDY, THE ELECTROPHORETIC PATTERN OF ENZYMATIC DIGESTION OF artemia urmiana SAMPLES WERE DIFFERENT AND GENETIC POLYMORPHISM AND POPULATION DIVERSITY ARE OBSERVED AMONG THE STUDIED SAMPLES.