It has long been known that animals like hydras, which can live separate lives after being divided into two or more parts. But is it possible for two different animals to merge into one? As it turns out, they can.
At least, this is what pairs of comb jellies, Mnemiopsis leidyi, also known as sea walnuts or simply mnemiopsis, are capable of. A new study has been published in the journal Current Biology.
Researchers discovered that after injury, two comb jellies fused to such an extent that they synchronized their muscle contractions and merged their digestive tracts to share food with each other. The study results also indicate that their nervous systems became unified, allowing them to share nerve impulses.
"Our findings suggest that comb jellies may lack an allorecognition system, which is the ability to distinguish between oneself and others," explained study author Kei Jokura from the University of Exeter (UK) and the National Institute for Natural Sciences in Okazaki (Japan).
An unusual specimen was observed while monitoring the behavior of a population of comb jellies in a water tank. It appeared to have two ends, raising the question of whether this was some kind of mutation or if the creatures had simply fused together.
To confirm this, the scientists cut off body parts from several pairs of specimens and placed them close enough together to allow them to connect. As it turned out, this worked in 9 out of 10 cases.
After merging, the comb jellies happily lived together for at least three subsequent weeks. The fusion occurred overnight, during which time they completely became one entity and synchronized their movements.
The creatures also fused their digestive systems, although two anuses remained, and both remained functional.
The researchers believe this study could be beneficial for future work in the field of regeneration, and they will continue to investigate what happened with these comb jellies.
Comb jellies (Ctenophora) are a group of invertebrate animals that resemble jellyfish on the outside, though they have no relation to them. Upon closer inspection, the differences between them become apparent:
There are hypotheses suggesting that comb jellies are the most ancient multicellular organisms on our planet, even predating sponges; however, research on this topic has yielded conflicting conclusions.
As previously reported, scientists recently described a new species of wasps that lay their eggs in adult flies. The larva then burrows its way out and literally bursts from the chest, much like a xenomorph in the movie "Alien."