In later years, several other specimens have also been found.

Only ten individual specimens were found between 1910 and 1996.

So far, very few specimens have been found, all female.

Little is known about its history, because few specimens have been found by scientists.

No other specimens have ever been found in the wild.

"It gets more difficult each season to find good specimens for my clients."

Some specimens have been found with three black dots on the top of the head.

Since the original discovery, many more specimens have been found.

This species is the best known as many relatively complete specimens have been found.

One specimen, was found preserved and is thought to be 37 million years old.