An Animal Friendship Thought to Have Ended 250 Million Years Ago Is Still Flourishing Off the Coast of Japan - Gizmodo

Off the southwest coast of Japan, a group of animals has been coexisting in a close relationship that researchers thought didn’t exist in the modern age.

But at the end of the Paleozoic, the fossil record for these animals coexisting ran cold.

According to Mikołaj Zapalski, a paleontologist at the University of Warsaw and lead author of the new study, the most recent fossil of crinoids and corals coexisting in this fashion is 273 million years old.

Zapalski said that corals and crinoids are also found in fossil deposits younger than the Paleozoic (which ended some 250 million years ago), “but for unknown reasons they were never found together.” So the team was pretty stunned when they found the animals associating actively in the deep water off Japan.