Asked by: Adam King, Huddersfield
As palaeontologists uncover more fossils around the world, we keep finding new dinosaurs from the Triassic Period: the first interval of dinosaur history.
Currently, the oldest known dinosaurs come from Argentina, and they’re about 231 million years old. There are several dinosaurs of this age found together, including the horse-sized meat-eater Herrerasaurus, the dog-sized meat-eater Eodromaeus (a distant relative of T. rex), and several dog-to-bear-sized cousins of the giant long-necked sauropods, including Panphagia and Eoraptor.
The fact that so many dinosaurs, with different diets and sizes, lived at this time tells us that dinosaurs were already diversifying soon after they evolved from other reptiles. But none of these dinosaurs were giants, and none were at the top of the food chain. Those species would come later, during the Jurassic Period.