Diving Pterosaurs?

http://en.wikipedia.org/wiki/Pteranodon

"Traditionally, most researchers have suggested that Pteranodon would have taken fish by dipping their beaks into the water while in low, soaring flight. However, this was probably based on the assumption that the animals could not take off from the water surface.[2] It is more likely that Pteranodon could take off from the water, and would have dipped for fish while swimming rather than while flying. Even a small, female Pteranodon could have reached a depth of at least 80 centimetres (31 in) with its long bill and neck while floating on the surface, and they may have reached even greater depths by plunge-diving into the water from the air like some modern long-winged seabirds.[2] In 1994, Bennett noted that the head, neck, and shoulders of Pteranodon were as heavily built as diving birds, and suggested that they could dive by folding back their wings like the modern Gannet.[2]"

What can't these amazing pterosaurs do?