13-year-old student discovers a new species of transparent jellyfish

In 2018, a 13 year old on a dock in Tanabe Bay, Japan, scooped up tiny drifting animals and raised them at home. Those creatures turned out to be a new species, now called Orchistoma integrale.

The find extends a little known genus into the northwest Pacific for the first time, and it is tied to a new peer-reviewed paper.

Orchistoma integrale is different

The work was led by Ryoya Sugimoto, the corresponding author at the University of Tokyo. His research focuses on hydrozoan development and species identification.

The integral jellyfish is a hydrozoan, a jellyfish relative with a medusa and polyp stage. It is not a true jellyfish in the strict sense used by specialists.

Adults show a rounded bell with prominently curled gonads, reproductive organs shaped like a long S. The mouth has many frilled lips, and the tentacles lengthen as animals mature.

“The integral jellyfish belongs to an order of organisms that’s pretty ubiquitous. You can find organisms from this group almost anywhere you go,” said Allen G. Collins, director of NOAA Fisheries’ National Systematics Laboratory.

While many jellies add tentacles in tidy fours, this species grew from four to six, then increased irregularly as individuals aged. 

Finding Orchistoma integrale

Sugimoto first became interested after a childhood sting sent him to field guides. He memorized Japan’s jellyfish and taught himself how to raise them in simple tanks.

“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,” said Collins. In 2018 he noticed animals that did not match any species he knew and kept them alive through maturity. 

His team analyzed DNA and shape to determine whether the animals were known or novel. That combination, with careful rearing notes, gave a stable basis for recognizing a species rather than a variant.

The study’s type material, the official set of specimens, anchors the scientific name to bodies that can be examined. That practice ensures that future identifications are not guesswork and can be checked against the originals.

From early polyp to adult medusa

Sugimoto also raised the polyp, the small attached life stage that buds free swimming medusae. That effort marked the first time this early stage was documented for the entire Orchistoma genus.

Life cycle documentation matters in simple ways. It tells scientists when the medusae appear, how fast they grow, and where young stages hide.

His notes showed the manubrium, a throat-like tube leading to the mouth, is short and ends in many lips. The peduncle, a slender stalk that supports internal structures, is unusually long for this group.

Those traits made Orchistoma integrale stand out from close relatives described in other oceans. The differences were consistent as the animals grew in tanks and in the field.

Why Orchistoma integrale matters

This report is the first record of this family in Japan and the first record of the genus in the northwest Pacific. It closes a gap in where these animals are known to live and points to either under sampling or a recent change.

Finding a first can spark hard questions. Was the species always here, moving in small numbers, or has it shifted range with currents and climate.

The authors connected DNA data to the type material, which allows detection by eDNA. Environmental DNA, genetic traces shed by organisms into water, lets scientists find species without catching whole animals.

That is only possible when DNA sequences are tied to a described species and a real specimen. Otherwise, surveys recover anonymous fragments that no one can place.

What genetics add to the picture

The paper combined morphological traits with molecular characters to place the species within Orchistoma. That dual approach guards against mistaking a growth stage for a novel species.

Sequence data linked to a named specimen can be applied to water samples in ports and bays. It turns routine monitoring into a tool for mapping distribution.

Over time, those DNA maps can test whether ranges expand or contract. They also show when populations pulse in late spring or early summer.

If patterns shift, managers can ask whether local changes in nutrients, prey, or currents might be at work. Data then move from cabinets to decisions that affect coasts people use every day.

Lessons from Orchistoma integrale

“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,” said Collins. That simple fact hints that careful dockside observing still pays off.

Future surveys can check coves and harbors near Tanabe Bay for seasonal pulses. Similar sampling along current paths would test whether the species is spreading.

Well curated collections keep the science honest. A holotype, the single specimen that defines a species name, lets future scientists confirm identifications with microscopes instead of memory.

A teenager with a hand net and patience started this story. Collaboration, careful rearing, and genetic tools finished it with a clear name and a place on the map.

The study is published in Plankton and Benthos Research.

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