Bizarre Ancient Sea Creature Was Well-Armed for Feeding

Tribrachidium was a denizen of the shallow seas about 550 million years ago, during the late Ediacaran period. Oddly, Tribrachidium had three-fold symmetry, meaning three segments  were mirror images of each other. "Because we have no obvious modern comparison, that's made it really hard to work out what this organism was like when it was alive — how it moved, if it moved, how it fed, how it reproduced," said Imran Rahman, a research fellow at the University of Bristol, in the United