Defying the Typical Life Cycle In the normal jellyfish life cycle, the animal is born, develops, lives out its reproductive stage and then moves toward death. The hydrozoan species Turritopsis dohrnii (formerly Turritopsis nutricula) is capable of cycling from a mature adult stage to an immature polyp stage and back again. These species can cycle from a mature state to an immature one, so there’s no limit to their life span and they can bypass death. Found in the Atlantic Ocean, Turritopsis nutricula is capable of a form of biological immortality -- although it's not impossible to kill these jellyfish. This is the first metazoan known to revert to a colonial, juvenile morph after having achieved sexual maturity in a solitary stage. Turritopsis nutricula, from newly liberated to fully mature individuals, can transform back into colonial hydroids, either directly or through a resting period, thus escaping death and achieving potential immortality. This means no natural limit to … Melanie Lasoff Levs April 13, 2011, 1:33 p.m.

Turritopsis nutricula was the first described Hydrozoan species able to revert its life cycle (Bavestrello et al., 1992). This tiny jellyfishes amazing ability to virtually live forever is something that the scientific and medical community needs to recognize more.
Turritopsis nutricula (T. nutricula) is the one of the known reported organisms that can revert its life cycle to the polyp stage even after becoming sexually mature, defining itself as the only immortal organism in the animal kingdom. Turritopsis nutricula, or sometimes – Turritopsis dohrnii, is able to transform its cells from mature state back to immaturity, in other words – back to youth. The Turritopsis nutricula jellyfish has displayed a remarkable ability to regenerate its cells in times of crisis. Immortal Jelly Fish Life Cycle. Therefore, the animal is having prime importance in basic biological, aging, and biomedical researches. It is no different to the turritopsis dohrnii, except that it can revert to its polyp stage at any time. T. nutricula is able to undergo normal, sexual reproduction as well. No surprise that scientists consider the Turritopsis Nutricula immortal; these creatures are, in fact, silently invading oceans across the globe. The authors claimed that the reversion occurred only in young medusae, and not in sexually mature animals. This is diagramed below under the "Normal" life cycle. The medusa, under stressed conditions, develops back to the polyp stage. It is one of the few known cases of animals capable of reverting completely to a sexually immature, colonial stage after having reached sexual maturity as a solitary individual. Turritopsis nutricula is not only an extraordinary jellyfish that has almost complete control over its own cells, but could help to cure cancer. Turritopsis dohrnii, also known as the immortal jellyfish, is a species of small, biologically immortal jellyfish found worldwide in temperate to tropic waters.

The medusa leads a regular cycle of life, but after maturing and mating, it reverts back to its initial state – a polyp colony. However, when environmental pressures increase T. nutricula can revert to a colonial, asexual state.
There are two distinct stages of a jellyfish’s life cycle: the polypoid stage and the medusa stage.