Recent research conducted by a team at the University of California, Berkeley, has revealed that a species of gelatinous marine invertebrates, known as sea walnuts or comb jellies, can fuse together when injured. This groundbreaking discovery was made after an unusually shaped individual was observed in a laboratory tank, prompting researchers to investigate further.

The unusual creature displayed two “aboral ends” and two mouths, leading the team to hypothesize that it was the result of two separate animals merging. To test this theory, pairs of sea walnuts were subjected to injury on one side and then pinned together overnight, leading to successful fusion in nine out of ten trials.

As the experiments progressed, scientists discovered that fusion could occur within just a few hours, demonstrating the resilience and adaptability of these marine organisms. Notably, when one side of the fused jelly was stimulated, both individuals responded, suggesting a possible merging of their nervous systems. This finding is particularly significant given the limited understanding of ctenophore nervous systems.

The research not only highlights the potential for comb jellies to serve as models for studying the evolution of self-recognition systems but also sheds light on tissue grafting and regeneration processes in various organisms, including humans.

Further observations revealed synchronized muscle contractions between the fused pairs, indicating a level of neurological integration. When one jelly was fed, the fluorescently labeled food particles passed into the digestive system of the other, although the expulsion of waste was unsynchronized, pointing to distinct digestive processes.

The study implies that comb jellies possess minimal mechanisms for distinguishing their own tissues from those of others of the same species. This insight could enhance understanding of how multicellular organisms recognize their own cells, advancing knowledge of cellular cooperation and integration.

The research contributes to a growing body of knowledge about ctenophores, which are now recognized as descendants of the common ancestors of all animals. As such, these creatures may provide critical insights into the fundamental principles governing neuronal function and evolutionary biology.