Compiling a ’dentist’s handbook’ for penis worms

A new study of teeth belonging to a particularly phallic-looking creature has led to the compilation of a prehistoric 'dentist's handbook' which may aid in the identification of previously unrecognised specimens from the Cambrian period, 500 million years ago. Penis worms were fearsome beasts, and extremely successful ones at that - Martin Smith It sounds like something out of a horror movie: a penis-shaped worm which was able to turn its mouth inside out and drag itself around by its tooth-lined throat, which resembled a cheese grater. But a new study of the rather unfortunately-named penis worm has found that their bizarre dental structure may help in the identification of previously unrecognised fossil specimens from the time on Earth when animals were first coming into their own. Reconstructing the teeth of penis worms, or priapulids, in fine detail has enabled researchers from the University of Cambridge to compile a 'dentist's handbook' which has aided in the identification of fossilised teeth from a number of previously-unrecognised penis worm species from all over the world. The results are published today (6 May) in the journal Palaeontology . The researchers used electron microscopy to examine the internal structure of the teeth of these creatures, which first emerged during the 'Cambrian explosion', a period of rapid evolutionary development about half a billion years ago, when most major animal groups first appear in the fossil record. The teeth of these Cambrian priapulids had different shapes according to their function: some were shaped like a cone fringed with tiny prickles and hairs, some were shaped like a bear claw, and some like a city skyline.