Cambrian’s ‘penis worm’ dragged itself around using its tooth-lined throat

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Strange is the word that can be used to describe many of Cambrian Period’s species that emerged during the ‘Cambrian explosion’ some 500 million years ago and one of them is the phallic-looking creature, which has been named rather oddly – the penis worm. According to researchers these worms, which are presumed to be living in burrows under the sea, moved around by dragging themselves using their tooth-lined throat.

Scientists at the University of Cambridge describe the carnivorous Penis Worm, or Ottoia, as a fearsome beast capable of gobbling up anything that crossed their path, including worms, shrimp and other marine creatures. The peculiarity of the ‘penis worm’ was that it could turn its mouth inside out to reveal a tooth-lined throat that looked like a cheese grater and using them could move around when needed.

Because its teeth are less than a millimeter in size, researchers used high-powered microscopes to find out more about their structure. The investigators found that the teeth had a scaly base and were fringed with tiny prickles and hairs. By reconstructing what the Penis Worm’s teeth looked like, the researchers discovered fossil teeth from a number of previously unrecognized Penis Worm species all over the world.

“Modern penis worms have been pushed to the margins of life, generally living in extreme underwater environments,” said Dr Martin Smith, a postdoctoral researcher in Cambridge’s Department of Earth Sciences and the paper’s lead author. “But during the Cambrian, they were fearsome beasts, and extremely successful ones at that.”

For this study, the researchers examined fossils of Ottoia, a type of penis worm, about the length of a finger, which lived during the Cambrian. The fossils originated from the Burgess Shale in Western Canada, the world’s richest source of fossils from the period, full of weird and wacky-looking creatures that have helped scientists understand how animal life on Earth developed.

“Teeth hold all sorts of clues, both in modern animals and in fossils,” said Smith. “It’s entirely possible that unrecognised species await discovery in existing fossil collections, just because we haven’t been looking closely enough at their teeth, or in the right way.”

Smith says that this particular research will enable them to compile a ‘dentist’s handbook’ that will help paleontologists recognize a range of early teeth preserved in the fossil record.