HIDDEN INVADERSmall but pervasive, this jellyfish-like hydrozoan takes several forms. It can survive tough times by collapsing into a blob and then growing back into its youthful, stalklike form. No wonder genetic testing is finding that it has quickly and stealthily spread throughout the oceans.Courtesy of M.P. Miglietta A jellyfish-like hydrozoan with a novel power to rewind its life cycle has been spreading rapidly around the world’s oceans without anyone taking much notice, researchers say.
The life history of Turritopsis dohrnii takes such twists and turns that only a new genetic analysis has revealed that the creature is invading waters worldwide, says Maria Pia Miglietta of Pennsylvania State University in University Park.
The first peculiarity of the seven species of Turritopsis had inspired biologists to describe these hydrozoans as “potentially immortal.” The adults form filmy bells reminiscent of their jellyfish relatives. When times get tough, faced with scarce food or other catastrophe, Turritopsis often don’t die. They just get young again.