Discovery in the depths of Japan: a new species of sea anemone blurs the lines between animals and architecture

A new species of sea anemone has been discovered in Japanese waters, whose shell creates a mobile home and helps the creature feed in the deep sea.

UNN reports with reference to Oceanographic Magazine.

Details

In the quiet depths off the Pacific coast of Japan, 200–500 meters below the surface, researchers have discovered a new species of sea anemone associated with a hermit crab. Unlike common anemones, Paracalliactis tsukisome interacts with its crustacean partners in a unique and previously unseen way.

The unusual cylindrical marine animal was found on shells inhabited by the hermit crab Oncopagurus monstrosus at a depth of 200-500 m off the Pacific coast of Mie and Shizuoka prefectures.

What distinguishes the atypical type of anemone

As experts explain, P. tsukisome is capable of secreting a strong, shell-like structure known as a carcinoecium. This material expands the fragile hermit crab shell, providing additional protection and stability as the crab grows. In return, the anemone gets a mobile home that helps it feed in nutrient-poor deep-sea areas.

3D visualization using micro-CT showed that the anemone attaches to the shell in a consistent, unidirectional manner, which may be related to both feeding and shell construction. Researchers also found out what and how P. tsukisome feeds. Stable isotope analysis showed that it feeds on organic particles, as well as crab feces. "An unusual but effective form of recycling on the deep-sea floor," experts note.

"This sea anemone challenges our assumptions about how simple animals perceive and respond to their environment," says Associate Professor Akihiro Yoshikawa of Kumamoto University. "It's an elegant example of how cooperation and evolution can shape form and function, even in the deep sea."

Recall

During a 38-day expedition in the Peruvian Alto Mayo region, scientists discovered 27 new animal species. Among the findings are an amphibious mouse, a tree salamander, and a fish with an unusual teardrop-shaped extension on its head.