A Surprising Encounter
Ryoya Sugimoto, a Japanese student at the University of Tokyo, has always been fascinated by marine life. He never expected that he would one day describe an undiscovered species, though.
Sugimoto first became interested in jellyfish when he was stung by one as a child. He turned to the internet to identify the species—a blue button jellyfish, Porpita porpita. Then he checked out the entirety of his local library’s collection of books on jellies and even taught himself how to raise jellyfish. He’s been enthralled by them ever since.
A 13-year-old Sugimoto was observing marine life from the docks of Tanabe Bay in Wakayama, Japan in 2018 when he came across some unfamiliar jellies. “I remembered all the jellyfish species of Japan from books I’d read, but these were morphologically different from any species I knew,” Sugimoto recalls.
He collected several dozen of the creatures to study in his home. As he raised them to maturity, they grew into a strange shape he had never seen before. Sugimoto decided to seek an expert opinion to determine what they were.
Sugimoto contacted Dr. Allen Collins, director of NOAA Fisheries’ National Systematics Laboratory and one of the world’s leading jellyfish experts. “When Ryoya first contacted me, I didn’t expect this to be something new, but I was excited to work with someone young and passionate,” Collins says. He offered to conduct genetic and morphological analyses of the specimens for Sugimoto.
“This was also a great opportunity to obtain some well-preserved specimens and document the genetics and characteristics of an organism from another part of the world,” Collins adds. The National Systematics Lab is located inside the Smithsonian National Museum of Natural History. The lab’s staff help to curate the museum’s collections of marine fish and invertebrates, a group of organisms that includes jellyfish, corals, anemones, squids, and crabs. Gathering biological samples from around the globe makes public databases more robust and can help us better understand and manage the species that live in our own waters. The National Systematics Lab plays an important role in these efforts.
Get to Know the Integral Jellyfish
Collins was excited to find that Sugimoto’s specimens were genetically and morphologically distinct. This was, in fact, a new species. Sugimoto dubbed it the integral jellyfish (integuraru-kurage in Japanese) for its uniquely shaped gonads, or reproductive organs, which resemble the mathematical symbol for integrals. Its official scientific name is Orchistoma integrale.
Despite its name, the integral jellyfish is not a “true” jellyfish—it’s a hydrozoan. Hydrozoans are a diverse group of more than 3,000 known species. They are closely related to true jellyfish, known as scyphozoans, as well as box jellyfish and stalked jellyfish. Scyphozoans like moon jellies and sea nettles are the species that typically come to mind when most people picture a jellyfish.
Collins also notes that the integral jellyfish has a particularly long projection, called a peduncle, with a short throat (or manubrium) at its end that hangs down from the central bell. Its manubrium ends in a mouth with many frilly lips. Other hydrozoans tend to have simple mouths with just four lips or no lips at all.
While most jellyfish have tentacles in multiples of four, the specimens that Sugimoto collected had four to six tentacles. As they matured, their number of tentacles increased irregularly, which is somewhat unusual. This growth pattern did not fit the characteristics of any species that Sugimoto knew, motivating him to continue investigating whether it might be an undescribed species.
“The integral jellyfish belongs to an order of organisms that’s pretty ubiquitous. You can find organisms from this group almost anywhere you go,” says Collins. “But this discovery is surprising in the sense that we’ve never seen a species from this family in the northwest Pacific Ocean.” Sugimoto adds that finding this species in Japan raises additional questions: Why hasn’t it been discovered before? Did it suddenly appear here? Has it been introduced from another location, or is its range changing?
Sugimoto and Collins will continue to study the integral jellyfish, but they do know some basic components of its ecology. “This is a shallow water species; it was found right off the docks. We’re not exactly sure what it’s eating, but probably small copepods or other jellies,” Collins says. Sugimoto has also been able to raise the polyp stage of this new species, the first time that this stage has been identified for any species in this genus.
A Legacy of Discovery
This isn’t Collins’ first time describing a new species. In 2017, he helped distinguish the bay nettle jellyfish (Chrysaora chesapeakei) from the sea nettle (Chrysaora quinquecirrha), previously thought to be the same species. He’s also collaborated in describing a species of comb jelly (Duobrachium sparksae) and the E.T. sponge (Advhena magnifica). The official name of the Bonaire banded box jelly (Tamoya ohboya), which he helped describe, was bestowed by the winner of a public competition in 2011.
The thrill of encountering an undiscovered creature never gets old for Collins. “It’s a message scientists repeat whenever we describe a new species, but there’s just so much to discover!” Collins says. “We know that there are so many species out there that are yet to be described and characterized—hundreds of thousands in the ocean. And there is an imperative to do this work.”
Characterizing the genetics of new species like the integral jellyfish also allows us to detect them in environmental samples. As organisms move through their ecosystems, they shed biological material, called environmental DNA, or eDNA. We can extract eDNA from water samples to learn about which species may be present in certain ecosystems—but only if we can match that DNA to a described species. This technique, which many NOAA scientists are now using, can be especially useful for studying elusive and cryptic marine organisms such as the harbor porpoise. Similar techniques can be used to understand food webs by sequencing gut contents.
Understanding, categorizing, and characterizing biodiversity, Collins emphasizes, is key to effective conservation and management. “Jellies are integral parts of their ecosystems,” he says. “When we understand what they are, we can better understand what they’re doing, and that tells us how their ecosystem is doing on the whole, especially as it’s perturbed by natural and human impacts.”
At the University of Tokyo, Sugimoto continues to study marine science. His current research is focused on the rejuvenation process, a unique biological ability that makes some hydrozoan species “immortal.” Describing the integral jellyfish has been a formative experience that has boosted his confidence, and he looks forward to continuing to express himself through his academic pursuits. “By using jellyfish as a common language, along with English, I have come to know the joy of connecting with others across borders, sharing my passion and interests,” Sugimoto says.
