These sea creatures can fuse their bodies

In a Frankenstein-y feat, a small, gelatinous sea creature can merge its body with a neighbor’s. The animals — most often often called sea walnuts, a form of comb jelly — can then sync up their bodily functions, researchers report October 7 in Current Biology.

Biologist Kei Jokura first discovered the mashup when he found an unusually large sea walnut (Mnemiopsis leidyi) floating in a bunch tank. Turned out, it used to be definitely two jellies joined together.

Jokura, who did this work while at the Marine Biological Laboratory in Woods Hole, Mass., suspected they had change into injured contained within the collection process and, caused by tight quarters, fused their bodies while healing. Comb jellies are known for his or her ability to regenerate parts of their very own body, nevertheless the sight of two hooked up sparked Jokura’s curiosity.

“In the foundation, I used to be very surprised,” says Jokura, now at the National Institutes of Natural Sciences in Okazaki, Japan. Then he thought, “Let’s reproduce this lower than the microscope.”

Jokura and colleagues took pairs of comb jellies, trimmed off a section from every of them and pinned them to dissection dishes with their cut ends abutting. In 9 out of the 10 pairings, the injury websites fused overnight, creating a continuous stretch of tissue.

They didn’t just appear to be one organism — they acted like one also. When prodded on one side of the dual jelly, both bodies spoke back by contracting. That suggests the jellies’ nervous systems may even have fused, the authors say (SN: four/20/23). And both bodies circulated food between them, despite the team feeding best one mouth of the duo.

Because comb jellies are spread out contained within the open ocean, fusion most undoubtedly happens best in a lab setting, says Steven Haddock, a marine biologist at the Monterey Bay Aquarium Research Institute in Moss Landing, Calif. In his own work with comb jellies, he’s seen every other species, the ocean gooseberry (Pleurobrachia pileus), fuse after collection, but no longer in a synchronized way. “Nothing like this, where they’re coordinating their reactions,” he says. “It’s pretty extraordinary.”

The sea walnuts’ fusion prowess suggests that the animals lack the pliability to distinguish between their body and every other body, a trait most often often called allorecognition. In humans, allorecognition is what could cause the body to reject organ transplants. Comb jellies are just a couple of the oldest lineages of animals, which suggests that the absence of allorecognition in sea walnuts may hold clues for the way the trait evolved (SN: 12/12/13). But to keep in mind of that, Jokura says, more research must be done on their neurology and the genes to blame.