The first true dinosaurs first appeared about 230 million years ago. The first dinosaur fossils are distinguished from those of their reptile ancestors by their more upright stance, with legs directly beneath the body instead of splayed to the side, as with other reptiles. The earliest dinosaur fossils were found in South America, although a December 2012 fossil discovery in southern Africa casts some doubt on a South American origin.Know More
The first dinosaurs were a group of species known as theropods. They walked on two legs and varied in size from the 20-pound Eoraptor to the 400-pound Herrerasaurus. The group spread relatively quickly from South America to North America, and then further to Africa and Eurasia. Many famous types of dinosaur, including tyrannosaurs and allosaurs, were later species of theropod.
Dinosaurs with four legs evolved from theropods, but they are not considered theropods themselves. These species, which were mostly herbivores, were split into two groups by their hip structures. Lizard-hipped species included the giant sauropods. Bird-hipped groups included the armored anklyosaurs and the horned ceratopsians. Scientists think that all bird-hipped dinosaurs descend from a species called Eocursor, a species from South Africa, which, in turn, was probably descended from Eoraptor.Learn more about Dinosaurs
There are a few well-researched theories about why dinosaurs are extinct; one of the most prominent theories hypothesizes that a massive asteroid impact killed off the dinosaurs. Another states that heavy volcanic eruptions across the Earth may have been responsible.Full Answer >
True dinosaurs were not swimmers. There were a number of very large aquatic reptiles that lived during the age of the dinosaur, but they were not technically dinosaurs. These creatures belonged to one of several other groups, such as ichthyosaurs, plesiosaurs and mosasaurs, which were types of marine reptiles.Full Answer >
Types of dinosaurs include the apatosaurus, the anklyosaurus and the stegasaurus. The apatosaurus was a plant-eating dinosaur that lived during the Jurassic Period, between 115 to 150 million years ago.Full Answer >
There is evidence that dinosaurs did not have a single, uniform and universal diet but rather a wide variety of dietary habits, with evidence supporting the idea that carnivorous, herbivorous and omnivorous species all existed. Different feeding styles were also likely, with some carnivorous species hunting prey such as mammals and small reptiles, while other carnivores may have been opportunistic carrion scavengers. There was likely even a good range of dietary variety amongst the herbivorous dinosaurs, which may have made up the majority of all dinosaur species.Full Answer >