This challenges some of the most fundamental theories about how and when dinosaurs evolved.
Coldblooded reptiles are dependent on the environment for body heat.
Warmblooded mammals and birds generate their own body heat and are more tolerant of temperature extremes. Birds and mammals also have more physical endurance and can be swifter. Some dinosaur experts said discovery of the fossilized heart will change basic views about the dinosaur and send researchers scrambling to do more X-ray studies of intact specimens. It is a landmark in the field. If verified by other studies that a rock-hard mass in the fossilized chest is a heart, it will mark the first time that scientists have been able to study the cardiac system of dinosaurs.