The fossil is imbedded in hard lumps of iron carbonate. ‘The only thing we knew about it was what the creature looked like from above,’ Garwood says.
Garwood is no stranger to this kind of problem: back in August he uncovered minute details of ancient spider-like creatures without even cracking the fossils open (see story: X-rays bring extinct spiders back to life). To do this, he used the Natural History Museum’s CT-scanner to take thousands of x-rays and build a 3D image of the fossils.
Now he has applied the same principle to the roaches. The x-rays revealed precious details about the wings, mandibles, legs and the antennae that ‘were never seen before in fossil roaches from this age,’ says Garwood.
Archimylacris eggintoni’s mandibles are very similar those of modern cockroaches and it probably ate decaying matter, possibly dead leaves lying around the forest floor.
One of the fossil’s antennae is parallel to the body, while the second sits at a high angle. This suggests that the roach was able to sweep its antennae in arc-like movements like modern cockroaches do.
Its legs were long and thin and were articulated in five different places near the end. This provided extra speed and allowed the roach to run very fast over irregular terrain. It also had claws that would probably have helped it climb trees to lay its eggs or escape from predators.