Dr Mikołaj Zapalski from the Faculty of Geology, University of Warsaw (UW) and Dr Eng. Marek Dohnalik from the Oil and Gas Institute – National Research Institute, together with scientists from Japan, discovered marine animals- crinoids covered by corals in the Pacific waters. 

Such symbioses were known from the Paleozoic seas, but seemed to be extinct. Researchers have described an ecological “living fossil” that has not been found in the seas for 273 million years. The scientists’ article was published in the journal “Palaeogeography, Palaeoclimatology, Palaeoecology”.

The test animals were fished from a depth of 100 meters on the Pacific coasts of the Honshu and Shikoku islands. The research was conducted using a computer microtomograph. The results showed that, unlike their Paleozoic ancestors, today’s corals did not modify their host’s skeleton. Despite such differences in the skeleton record, the discovered coral- crinoids pairs may serve as a model for the corresponding Palaeozoic interactions.

More:
https://www.sciencedirect.com/science/article/pii/S0031018221002042?via%3Dihub