A Shimmery Sea Blob From The San Juans May Have Just Upended Evolutionary History

May 22, 2014

A squishy little sea creature fished out of the Salish Sea may be rewriting our history of how animal life first evolved.

They’re called comb jellies, and they have nothing to do with hair products. They are translucent blobs that propel themselves with rows of shimmering threads called cilia.

Scientists captured specimens at the University of Washington Friday Harbor Laboratories and analyzed their genomes, coming to two pretty startling conclusions. First, these animals have nervous systems, but they look almost nothing like those of people or fish, or any other animal on Earth.

“I just think of it as a very unique life form,” said Billie Swalla, the lab’s interim director.

The comb jelly is an example of developing a complex nervous system that uses a very different signaling method than the rest of the animal kingdom. They appear to be so unique that one of Swalla's colleagues calls them “aliens.”

What may be even more surprising is that these aliens are our relatives. Scientists have long thought multicellular life began with sponges, which have no nerves or muscles. They just sit there and filter water. The thinking was animals got more complex much later.

But the comb jelly, a predator with sophisticated anatomy, seems to actually be the first branch on the evolutionary tree, predating the more primitive-seeming sponges.

“It’d be very exciting to me to think that we had an ancestor that, you know, had muscles, nerves and these different kind of body plans,” said Swalla.

Exciting for her, maybe, but just think how the sponge people must feel.

“The sponge people especially are very unhappy with this. I have a lot of friends who work on sponges and they’re very, very unhappy because it’s kind of knocking them out of the basal position,” Swalla said.

Swalla was quick to say more research is needed to verify the findings. They’re published in the journal "Nature."