How many kinds of dinosaurs were there?

Although there were many species of dinosaurs, there were only about 50 different kinds.  For example, one kind was the Ceratopsia (better known as the triceratops) kind, and fossil records have shown many variations coming from this one kind. You see that they all have many similarities and some differences, but it is easy to see that they are all just variations of the Ceratopsia kind. 

 

Variations of the Ceratopsia kind (Source: Answers in Genesis)