How did the Pterodactyls fly?

Pterosaurs were flying reptiles that lived from about 240 million to about 65 million years ago. They varied greatly in size. The wings of the smallest pterosaur measured only a few inches from tip to tip. The wings of the largest pterosaur measured 39 feet (12 meters). The smaller pterosaurs probably ate insects. Some of the larger pterosaurs fed on fish, lizards, and other small animals.

Most scientists believe that pterosaurs were good fliers. They had light, hollow bones. Three clawed fingers and a long fourth finger stretched from the end of each front leg. Each wing had skin that stretched from the side of the body to the tip of that fourth finger. Fur may have covered the pterosaur's body and kept the animal from losing body heat.

Pterosaur. (2013). In World Book Kids. Retrieved from

How many types of Tyrannosaurs were there?

Up to the end of the 20th century, it was thought there were just 4 or 5 species of the Tyrannosaurus dinosaurs. Now 20 species have been described. It seems they lived longer and in a greater diversity of environments, including Australia.