A basket-shaped organism (tentatively *shootroot cunabulum*) with no clear Earthly analog. Anatomically similar to a plastic starfish, or to an opened variety of Earth's extinct blastoids.
1. Animal anatomy The flattened, fibrous 'leaves' are the arms of an animal loaded with photosynthetic symbiotes. The central structure houses a digestive system and a hard, sticky cradle (the cunabulum). A second ring of arms grows into the seabed, seeking crevices in the rock.
2. Preferred symbiote The cradle is an exchange site with a symbiotic partner (such as the lucifer rotsac). Spectrogenetic analysis suggests the cradle shootroot is younger than the rotsac. It may have originally parasitized free-floating lucifer rotsacs, before evolving a niche as an anchor: providing a refuge and minerals to the rotsac in exchange for a share of the rotsac's fermented food.
3. Plastic fibers Although it lacks the true cell walls of Earth plants, the cradle shootroot strengthens its tissues with bioplastic fibers. Too tough to cut by hand, they could be severed by a cutting tool.
Assessment: tough fibers could be used to synthesize fabric, possibly food.