At their longest, ribbon worms can grow up to 180 feet, or the equivalent of two blue whales or 720 gummy worms. Turns out, these lanky crawlers also have lengthy lifespans.
For over 20 years, the 3-foot-long ribbon worm Baseodiscus the Eldest (B for short) was more a “long-time acquaintance” than an experiment to Jon Allen, a biologist at the College of William & Mary. Until, that is, Allen decided to give B a genetic checkup.
Biologists had suspected nemerteans—ribbon worms—like B could have long lifespans, but the previous lab record was roughly three years. Baseodiscus the Eldest, living up to his name, had lived for around 30 years and, of course, continues to live. A detailed account of B’s life story was published in a recent paper for the Journal of Experimental Zoology.
“Our hope is that the work we have done here will show people that members of this phylum of worms are not short-lived, ephemeral members of the marine realm,” Allen told Gizmodo in an email. “Instead, they are decades-long inhabitants and often high-level predators in benthic [bottom-dwelling] ecosystems. More attention should be paid to them!”
The story of B
Allen, then a doctorate student, adopted B in 2005 alongside a tankful of abandoned invertebrates. For the next 20 years, B accompanied Allen in all his academic pursuits, where he “eked out a humble existence in the slime, content to munch on peanut worms and rest in the cool, quiet confines of his tank,” according to W&M News.
Once a year, B would make a quick appearance in one of Allen’s fall classes as an example of the creatures his students were studying.
“Baseodiscus is a charmer,” Allen told Gizmodo in an email. “He has a lovely red color, smooth skin, and is very flexible and highly mobile. He’s about a meter long, though he can certainly stretch to much greater lengths if he wanted, so he has a lot to recommend him as a teaching specimen.”
And it was one of Allen’s former students, Chloe Goodsell, that asked him just how old B was. Goodsell, now a PhD student at the University of California, Irvine, took the initiative to find out by sending a leading expert on worm genetics a tiny piece of tissue from B, Allen explained.
The results confirmed B is a nemertean of the species Baseodiscus punnetti and is at least 26 years old. That’s a conservative estimate, the paper noted, since B was “likely already a sizeable worm and therefore possibly at least several years old at the time of collection.”
Long live the worm
Typically, it is very rare for scientists to be able to calculate the age of ribbon worms. In B’s case, the worm’s long companionship with Allen allowed for a rough—although conservative—estimate.
Having B as a reference would be helpful to researchers studying similar species, in particular which biological and physiological characteristics correlate with age. According to Goodsell, creatures like B contribute to “the growing body of knowledge of what it takes to avoid senescence—or ‘getting old.’”
That said, as of now, Allen isn’t sure what B’s future holds as a research animal, although the elderly worm made his annual appearance in Allen’s class this fall, too.
“My hope is that he will continue to live a long life in his tank,” Allen wrote to Gizmodo.
