In an exciting discovery, researchers in Japan have identified a new species of starfish, Paragonaster hoeimaruae, thanks to a collaborative effort among scientists, fishers, and aquarium and museum staff.
Belonging to the Pseudarchasteridae family, Paragonaster hoeimaruae is a striking starfish with a red and beige coloration. It features five arms and measures just over 10 centimeters in diameter. This discovery underscores the value of collaborative efforts in uncovering the rich biodiversity of our oceans.
Contrary to their name, starfish are not true fish but are more closely related to sea urchins and sea cucumbers. Despite their seemingly docile appearance on beaches, starfish are significant marine predators. They come in a wide variety of forms, with some species boasting up to 50 arms, measuring up to a meter across, and living for several decades.
Globally, there are about 2,000 known species of starfish. This new discovery emerged from a partnership among researchers at the University of Tokyo, Enoshima Aquarium, the Marine Science Museum in Fukushima Prefecture, and the Yamaguchi Prefectural Fisheries Research Center.
The newfound species belongs to the Pseudarchasteridae family. Previously, only four species from this family, across two genera, had been recorded in Japanese waters.
“We discovered Paragonaster hoeimaruae off the coast of the Izu Peninsula in Sagami Bay, south of Tokyo, and another specimen in the Sea of Japan, northwest of Yamaguchi Prefecture,” explained lead researcher Itaru Kobayashi from the Misaki Marine Biological Station at the University of Tokyo.
These starfish were found at depths between 150 and 350 meters. They have a well-proportioned body with five arms and exhibit a beautiful red on their surface with a beige underside.
The research team collected various species from around Japan between 2021 and 2023. Specimens were gathered from shrimp and crab cages used by fishers in Hokkaido and Shizuoka prefectures, as well as from beam trawl surveys conducted by a Yamaguchi prefectural fisheries research ship. The starfish’s name, “hoei,” is derived from the fishing vessel Hoei-maru, which first collected the specimen.
The team also recorded starfish in previously undocumented locations. Notably, they found a large starfish species, Gephyreaster swifti, approximately 30 centimeters in diameter, off the north coast of Hokkaido. This species had previously only been recorded along the Pacific west coast of the United States and Canada, extending to islands in the Bering Sea.
“About 250 species of starfish inhabit Japanese waters, and we were surprised that such a large species had been overlooked,” said Kobayashi. “Our research highlights that the diversity of species in Japanese waters is still underestimated.”
These discoveries emphasize the importance of collaboration among fishers, aquariums, universities, and research institutions to enhance our understanding of marine biodiversity.
The study detailing this finding has been published in the Journal of Natural History.
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