The new species of anemone has been named ‘Stylobates calcifer’ and has an intimate interaction with another organism to develop. This great link has been established with a species of hermit crab called ‘Pagurodofleinia doederlein’.
As the researchers explain in their paper published in The Biological Bulletin , Stylobates is a small genus of sea anemones in the family Actiniidae that previously comprised four species: Stylobates aeneus from Guam and Hawaii, Stylobates birtlesi from northeastern Australia , Stylobates cancrisocia from eastern Africa and Stylobates loisetteae from northwestern Australia.
They all inhabit deep waters but this species was collected at a depth of 100 to 400 meters around the Pacific side, from the middle of the island of Honshu to Kyushu, Japan.
inhabiting a crab
The anemone occupies the entire upper part of the hermit crab’s shell and attaches itself by means of a hard shell-like secretion called carcinoecium.
“The symbiotic association between hermit crabs and sea anemones is an example of mutualism,” said University of Tokyo researcher Akihiro Yoshikawa, who led the study. “At least 35 symbiotic species of sea anemones belonging to 14 genera have been found in the chelipeds of hermit crabs or in the shells they inhabit.”
According to experts, this symbiotic relationship is beneficial to both parties: the hermit crab may not have to find new, larger shells, and the sea anemone may not have to change substrate.
“After about 43 hours from host shell change and 18 hours from old shell shedding , the sea anemone began to fully mount and cover the new shell. It was placed on the shell with the tentacles facing upwards, to allow the feeding of suspended particles from the water column and the hermit crab’s feeding detritus,” the researchers comment.
Experts suggest that the benefit to the hermit crab includes safety from parasites and predators that could affect its growth or shorten its life.
“This study is perhaps the first observation of the behavioral interaction of rarely studied carcinoecium-forming mutualism in the deep sea,” the authors conclude.
Referencia: Akihiro Yoshikawa et al. 2022. Carcinoecium-Forming Sea Anemone Stylobates calcifer sp. nov. (Cnidaria, Actiniaria, Actiniidae) from the Japanese Deep-Sea Floor: A Taxonomical Description with Its Ecological Observations. The Biological Bulletin 24 (2); doi: 10.1086/719160
