Evolution of the penis worm
5 December 2006
Images of the developmental stages of embryos more than half a billion years old were reported by Dr Phil Donoghue
In one instance they have exposed the internal anatomy of a close relative of the living penis worm. Another case has revealed a unique pattern for making embryonic worm segments, not seen in any animals living today.
The images were revealed using a revolutionary new technique – synchrotron-radiation X-ray tomographic microscopy.