Researchers from Okinawa Institute of Science and Technology (OIST), as well as other universities in Japan and Australia, have reported progress in cataloguing the abundance of life in the seagrass beds and coral reefs surrounding the Japanese sub-tropical islands of Okinawa, describing two new species of pygmy squid. Such areas are some of the most biodiverse ecosystems on the planet, being home to more than 360 species of coral alone.
Named the Ryukyuan Pygmy Squid (Idiosepius kijimuna) and Hannan’s Pygmy Squid (Kodama jujutsu), the new species’ names take inspiration from Japanese folklore. The Ryukyuan Pygmy Squid is named after the short, red-haired forest fairies that are said to live in the banyan trees of Okinawa. Like their namesake, the squids are tiny, feature red colouration and spend most of their time in their forest habitat, attached to vegetation in shallow seagrass beds close to the coast. Hannan’s Pygmy Squid is a newly discovered species within a whole new genus. The Kodama genus is named after the round-headed spirits that supposedly live in ancient trees, whose presence indicate a healthy forest. The species name comes from the preying behaviour of the squid, which resembles the Japanese martial art of Jiu-jitsu which revolves around grappling and using your opponent’s strength. “Kodama jujutsu preys on shrimp larger than itself by grappling with its small arms,” says Jeffrey Jolly from the Marine Climate Change Unit at OIST, who co-authored the paper detailing the discovery of the two species in the journal Marine Biology. The squid has also been observed with its arms raised and curled above its head, reminiscent of a martial arts pose.
Both species live up to their names, being truly tiny. With the largest specimen examined measured just 12 millimeters in length, finding the squid was not easy. Adding to their small size, both species are only active at night, and the Ryukyuan Pygmy Squid only appears in winter. Even then, this species has been caught and (incorrectly) identified many times before, being found in the relatively accessible, shallow seagrass beds. This is in contrast to the more elusive Hannan’s, which is only found in coral reefs, where, as Jeffrey Jolly puts it, “there are so many other things to look at, that finding a small squid the size of a pinky fingernail is not easy”.
[Image: Ryukyuan Pygmy Squid (Idiosepius kijimuna) attached to a blade of seagrass, photographed in the wild. Credit: Brandon Ryan Hannan]
More information: Amanda Reid et al, Two new pygmy squids, Idiosepius kijimuna n. sp. and Kodama jujutsu n. gen., n. sp. (Cephalopoda: Idiosepiidae) from the Ryukyu Islands, Japan, Marine Biology (2023). DOI: 10.1007/s00227-023-04305-1
