摘要：The oxygen stable isotopes investigation to elucidate thermoregulatory strategies in Middle Triassic basal sauro p- terygians is currently ongoing at University of Silesia and University of Maria Curie -Sk.odowska. The results of similar stud- ies on Late Mesozoic marine reptiles indicate that some of fully aquatic reptiles like plesiosaurs or ichthyosaurs could be warm-blooded animals. Our investigation is an important part of the aim of the research project "The Marine and Terrestrial reptiles in the Middle Triassic environmental background of Southern Poland" to solve the thermoregulation issue in basal marine reptiles and show how, and when did homoiothermy evolve in Sauropterygia.. Homeothermy and gigantothermy were important physiological adaptations which allowed sauropterygian ancestors to leave the shores and conquer the open seas and oceans.
