How do you know ancient sea lilies had endoskeletons?

Answer 1

Ancient sea lilies, belonging to the class Crinoidea, had endoskeletons made of calcareous plates called ossicles. Fossil evidence, including well-preserved specimens and their distinctive cup-shaped structures, demonstrates the presence of these internal skeletal elements. Additionally, the morphology of their ossicles and the patterns of growth observed in fossils provide further confirmation of an endoskeletal structure. Paleontological studies of crinoid fossils have helped reconstruct their anatomy and confirm the presence of endoskeletons in these ancient marine organisms.