Aquatic lifeforms that eluded human scientists' prying eyes and 'vanished' from the fossil record over a quarter-billion years ago have been discovered flourishing off the coast of Japan

Non-skeletal corals and crinoids, or sea lilies, were discovered by the researchers led by the University of Warsaw geology, proliferating on the Pacific Ocean floor, 100 metres below the surface, off the Japanese coasts of Honshu and Shikoku.

Coral attaches itself to the crinoid's stalk-like body, just below their feeding-fan appendage, to entangle them. It's an ideal environment for coral to survive and flourish, allowing them to achieve greater depths in the future. The two coral and crinoid animals in question were once common on the prehistoric seabed, but they gradually became extinct. Multiple versions of the two creatures continued to exist, and scientists believed that the two had broken it up for food because those organisms had died out.

"These specimens represent the first detailed records and examinations of a recent syn vivo association of a crinoid (host) and a hexacoral (epibiont), and therefore analyses of these associations can shed new light on our understanding of these common Paleozoic associations," the researchers wrote in their paper.

According to experts, it's unknown what the crinoids get from this symbiosis when corals climb up the sea column, but the pair has evolved. The crinoid's skeletal system had to conform to the coral's binding in the first iteration. On the other hand, the strengthened couple will settle in without the crinoid having to make any physiological concessions.

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