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Three new species of glowing sea worms found in Japan

A team of researchers from Nagoya University in central Japan has recently uncovered three new species of bioluminescent polycirrus worms, contributing to our growing understanding of the world’s luminescent organisms. Found in various parts of Japan, these small worms are typically found in shallow water and are well-known for their bioluminescence. 

The research group, which was led by Naoto Jimi and Special Assistant Professor Manabu Bessho-Uehara, comprised members from AIST, Olympus Corporation, and Japan Underwater Films Corporation. Their groundbreaking findings have been published in the journal Royal Society Open Science.

Despite over 7,000 species of luminescent organisms being known to science, only a small fraction of these have been studied in depth. One reason for this is the difficulty in classifying certain specimens, which can hinder accurate identification and limit the usefulness of comparing research findings. 

However, the team from Nagoya University has made strides in organizing polycirrus worms according to their diversity, ultimately leading to the discovery of the three new species, each emitting a blue-violet light.

Reflecting on the significance of their work, Jimi expressed the team’s amazement at the discovery and their sense of responsibility to document and classify these unique creatures. “Our previous research on the luminescence of the genus Polycirrus had established it as a valuable subject for bioluminescence studies. However, we later discovered what we thought was a single species of Polycirrus was actually three different species.”

To honor their Japanese origins, the researchers named the new species with cultural significance. Polycirrus onibi and Polycirrus aoandon were named after yokai, creatures from Japanese folklore, due to their bluish-violet luminescence. 

In the folktales, onibi (demon fire) is a will-o’-the-wisp type of yokai that leads travelers astray, while aoandon (blue lantern) is a ghostly figure that haunts lanterns in homes by turning their light an eerie blue color. The third species was named Polycirrus ikeguchii in recognition of Shinichiro Ikeguchi, the former director of the Notojima Aquarium.

“We used the names of Japanese yokai, such as onibi and aoandon, for the new species because the hazy violet-blue bioluminescence emitted by the Polycirrus species is strikingly similar to the descriptions of these creatures found in folklore,” said Jimi. “Polycirrus ikeguchii, on the other hand, was described from specimens collected in the Notojima region in Japan. As Shinichi Ikeguchi was the former director of Notojima Aquarium and helped to find the worm, it seemed appropriate to name it after him.”

The research team plans to build upon their findings to further investigate the molecular nature of bioluminescence, which has the potential to lead to the development of innovative technologies in the life sciences.

Jimi emphasized the importance of understanding luminescence mechanisms in contributing to medical and life science research. “Bioluminescence is a treasure trove of interesting and unusual chemistry. We intend to use our findings to deepen our understanding of the molecular nature of this phenomenon and apply this knowledge to the development of new life sciences technologies.”


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