In a surprising new discovery, scientists have found that two injured individuals of Mnemiopsis leidyi, a species of comb jellies or ctenophores, can fuse into a single entity. This phenomenon, which challenges our typical understanding of biological processes, reveals just how remarkable these planktonic creatures truly are.
Ctenophores, known for their translucent beauty and delicate movement in the ocean, appear to lack a mechanism called allorecognition—the ability to distinguish between self and non-self. This means that, when two comb jellies are injured and placed close together, they can merge, not just physically, but also functionally. Their nervous systems combine, allowing them to share nerve signals (or action potentials), and even their digestive systems become one.
The discovery was made by Dr. Jokura and his team, who were observing comb jellies in a seawater tank. After removing parts of their lobes and placing them side by side, they were astonished to see 9 out of 10 injured comb jellies fuse to form a single organism. Even more fascinating, the newly formed organism survived for at least three weeks, with its muscle contractions fully synchronized within just two hours. The digestive system also fused, enabling food taken in by one mouth to travel through their shared canal and exit through both anuses—although not at the same time!
While the exact benefits of this fusion are still unclear, the researchers believe that studying this phenomenon could provide valuable insights into how organisms integrate nervous systems and even how tissue regeneration occurs. It may also offer clues about immune system functions in species where the lines between individual organisms become blurred.
This discovery offers a glimpse into the hidden potential of the ocean’s lesser-known inhabitants, challenging what we think we know about biological boundaries and cooperation.
Video: Kei Jokura
Reference: Jakura et al., 2024. Rapid physiological integration of fused ctenophores. Current Biology