Halucigenia Worm of 500 MYA Had Circular Mouth

[Secular Elf]

500 Million Year Old "Smiling Worm" Rears its Head.

Heads or tails? Scientists finally have an answer in the case of the odd ancient worm Hallucigenia, which leaves fossils so bizarre that researchers once thought its top was its bottom and its back was its front.

Indeed, after decades, researchers have confirmed which side of Hallucigenia was the head, and found its circular "grinning" mouth lined with teeth, according to a new study detailed today (June 24) in the journal Nature. This toothy ring may be the link that connects creatures as diverse as spiders, nematode worms and teeny-tiny tardigrades — the cute and nearly indestructible micro animals also known as water bears.

"You look at a spider today, and you would have no idea," said study co-author Martin Smith, a researcher of paleontology and evolution at the University of Cambridge. "But actually, its simple mouth used to be much more complicated."

I remember reading about Hallucigenia and seeing pics of its fossil for the first time in Stephen Jay Gould's "Wonderful Life." It was one of oddest life forms from the Cambrian Explosion of life 500 Million Years Ago, and I think that book was written back in the early 90s. I still have it.

Full article: http://www.livescience.com/51331-bizarre...0478646760