A fossil slab discovered in Kansas 70 years ago and twice misidentified—first as a green alga and then as a cephalopod—has been reinterpreted as the preserved remains of a large cartilaginous fish, the group that includes sharks and rays. In a study published in the Journal of Paleontology, American Museum of Natural History researchers describe the fishy characteristics of the animal, which lived between 70-85 million years ago.