Quick Answer. When a solid turns into a liquid it is called fusion, more commonly referred to as melting. When a material moves from one state of matter into another it is called a phase transition. Fusion is just one of approximately different states that matter can phase through.
Before the dinosaurs, there were Triops. Fossil Triops more than 200 million years old have been discovered. By comparison, dinosaurs date back only about 60 million years...just 'youngsters' in terms of geologic time. Triops are distant relatives of trilobites. Triops means three-eyes while the name trilobite means three lobed or three segments.
Move deeper into the systematics of dinosaur groups by selecting one of the boxes containing a picture. With the discovery of many new species since the 1840s, the Dinosauria now contains two major groups of dinosaurs: the Ornithischia, or bird-hipped dinosaurs, and the Saurischia, or lizard-hipped dinosaurs. The division between the two groups was made by H.G. Seeley in 1888. The etymology behind the two names (bird-hipped vs. lizard-hipped) is not very accurate, since some saurischians had bird-like hips, and ornithischians' hips were somewhat birdlike due to convergent evolution, not due to direct ancestry.