In many bony fish and amphibians, the supraoccipital is never ossified, and remains as cartilage throughout life.
en.wikipedia.org The deposits also yield the remains of marine vertebrates, such as sharks and rays, bony fish, baleen whales, walruses, and dugongs.
en.wikipedia.org It is conserved throughout other mammals, reptiles, birds and bony fish.
en.wikipedia.org Other fossils found in this formation include many types of shellfish, bony fish, sharks, rays, birds, and marine reptiles like mosasaurs, plesiosaurs and sea turtles.
en.wikipedia.org The structure of swim bladders and the attached sonic muscles varies greatly across bony fish families, resulting in a wide range of sound production.
en.wikipedia.org