What kinds of dinosaurs are there?

To answer that question, we will need a starting point. In another topic (What is a dinosaur?), we discussed how dinosaurs were broken up into "bird-hipped" and "lizard-hipped. They can also be broken up into meat-eaters and plant-eaters. Or, we can simply go by their size and divide them into large and small. The best way is probably to go back and start with the "bird-hipped" (ornithischian) and "lizard-hipped" (saurischian) divisions. It will make things much easier and neater as we go along.

When discussing the various types of dinosaurs, what you are doing is basically making a family tree for dinosaurs. When scientists first started classifying animals, the taxonomic method (discussed in How do you classify a dinosaur?) was the main way of differentiating organisms. Today, many scientists subscribe to the idea of cladistics. Caldistics is the science of tracing the evolutionary path of an organism through common ancestry. Meaning, if you go back in time far enough, there is one organism that (in this case) all dinosaurs came from. This method is always being updated and dinosaurs are getting moved around all the time every time a new one is discovered. Nevertheless, I think this method is easiest to use for our purposes because it does resemble a family tree, which is something we are all familiar with.

Let's start the clade, or family tree, at the Superorder, dinosauria, which lands between Class and Order on our classification chart. Scientists do love their structure. From there, they branch off into either ornithischian or saurischian. And, then it gets complicated. The tree structure begins to branch out into many different directions. Now, again, we're trying to make this as simple as possible, so there are probably branches I may be skipping, but you will still get the idea of how the structure works. I will also try to give a dinosaur representative for each node on the branch. We will go into each type of dinosaur in depth in another topic.

Next-Dinosaur Family Tree-Ornithiscians.