Scientists Discover A Creature On The Ocean Floor Thought To Be Extinct

Researchers have discovered a symbiotic relationship between two marine life forms that are thriving on the bottom of the ocean. What's so surprising about these lifeforms, called "Living Fossils," is that they were thought to have gone extinct 273 million years ago. Scientists have discovered non-skeletal corals growing from the stalks of marine animals known as crinoids, or sea lilies.

The discovery was made on the Pacific Ocean floor off the coasts of Honshu and Shikoku in Japan. In their paper, the researchers wrote that the specimens represent the first detailed records and examinations of a recent syn vivo association of a crinoid host and hexacoral epibiont. The team believes analysis of the associations can shed new light on the understanding of common Paleozoic associations.

During the Paleozoic era, these two creatures proliferated with the seafloor fossil record showing many examples. In that fossil record, scientists say there are countless examples of corals over growing crinoid stalks to climb above the seafloor into the water column for filter feeding. The two creatures disappeared from the fossil record around 273 million years ago after the crinoids and corals went extinct.

Other species of both creatures emerge in the Mesozoic after the Permian-Triassic extinction but were never seen together in a symbiotic relationship. The two creatures were discovered at a depth of over 100 meters below the ocean's surface, and two different species of coral were discovered growing from the stems of living Japanese sea lilies. The two different species of coral include a very rare hexacoral in the genera Abyssoanthus.

Specimens were scanned using non-destructive microtomography revealing interior structures, and DNA barcoding was used to identify the species. The corals attached below the feeding fans of the crinoids aren't believed to have competed with their hosts for food and didn't affect the flexibility of the crinoid stalks. The researchers believe the anemone may have hindered the movement of the host's cirri which are thin strands that line its stalk.