Our research, published in Biological Reviews, offers a way to check. We found that two rival ways to estimate dinosaurs' body size - long thought to be fundamentally at odds - actually Smallest Ornithopod Dinosaur: Gasparinisaura (25 Pounds) FunkMonk (Michael B. H.)/Wikimedia Commons/CC BY GNU 1.2. Since many ornithopods —the two-legged, plant-eating dinosaurs ancestral to hadrosaurs—were slight in stature, it can be a tricky matter to identify the smallest member of the breed. The three-horned gigantic dinosaur is estimated to have measured 29.5 feet and weighed 10 tons hence making it one of the largest dinosaurs in history. 11. Triceratops Horridus. The triceratops is one of the most well-known dinosaurs. This is classified as the largest ceratopsian. This large theropod (bipedal, carnivorous dinosaur), which is Utah's state fossil, lived 155.7 million to 150.8 million years ago during the late Jurassic Period. From the seven individuals, 223 bones have been recovered to date, and their results pin the dinosaur at 37 meters (122 feet) in length and weighing 70 metric tons (as much as 15 African elephants), making it the largest animal to ever walk on Earth. Argentinosaurus' size was estimated from just 20 bones. This unusual dinosaur's enormous claws, shaped like giant scythes, could stop a tyrannosaur dead in its tracks. With broad hips and a pot belly, this dinosaur was perhaps the strangest-looking of all dinosaurs. An adult Therizinosaurus is thought to have weighed about 6 tonnes, that's as heavy as a large Tyrannosaurus rex. .

how heavy was the heaviest dinosaur