Missing Link in Worm Evolution Found

What does the image above remind you of? I know! Acorns, right? That's how researchers found the evolutionary missing link of the modern-day acorn worm, a wee invertebrate that live on the seabed.
Because they lack hard bones, soft-bodied marine animals aren't typically well preserved in fossils, but a specimen was found in the early 1900s in the fossil-rich area of Burgess Shale, Canada. While past researchers in the Smithsonian staff missed the connection, evolutionary biologist Jean-Bernard Caron didn't dick around when it comes to realizing that this was the missing evolutionary link:

... [Caron] “stumbled on drawers full of these worms” at the Smithsonian Institution in Washington, D.C. “I said, ‘Oh my gosh.’ I noticed a lot of these worms in bizarre-shaped rings, like mini Michelin tires in the rock,” said Caron, a co-author of the study.
After Caron and colleagues looked more closely at the fossils, they realized the newfound worm “really connects a lot of dots” in the evolution of hemichordates.

Get loads more info over at this piece by Christine Dell'Amore over at National Geographic's Weird & Wild blog.