Prehistoric insects imaged in 3-D

British researchers say modern technology has yielded 3-D images of 305-million-year-old insects that would be impossible to study otherwise. Scientists at the University of Manchester said a high resolution form of CT scanning allowed them to reconstruct two juvenile insects from the only evidence they left, three-dimensional holes in a rock. By placing the rocks in a CT scanner and taking more than 3,000 X-rays from different angles, the scientists were able to create the insects in cross section, the university reported Wednesday. While one of the insects is similar to a modern day cockroach, the other is characterized by a large number of sharp spines and is a new species and genus that does not exist today, they said. Both are members of a group called the Polyneoptera -- which includes roaches, mantises, crickets, grasshoppers and earwigs. "Around this time a number of early 'amphibians' were insectivores -- they lived by eating a lot of insects. The spiny creature was a sitting duck, as it couldn't fly, so the spines probably made it less palatable," researcher Russell Garwood said. "It is bizarre -- as far as we're aware, quite unlike any members of the Polyneoptera alive today. "We are hoping that work like this will allow us to better understand the biology and development of these early insects, and how major innovations may have come about," he said.