While its Cretaceous relatives are extinct, chimaera are still found in deep oceans, today! Like its distant relatives, sharks and rays, the chimaera’s skeleton is made of cartilage, which rarely fossilizes. Most fossil remains of the chimaera are limited to areas where the cartilage was very dense – usually claspers, fin spines, and mineralized jaw fragments. The jaw fragments, or “tritors,” look like porous bone, but are actually composed of fossilized cartilage and the white mineral, dahlite. Over millions of years, the dahlite is often dissolved by groundwater, leaving one easily identifiable feature – white-coated (pleuromin) rods in shallow pits of what looks like bone. The white coating is all that remains of the dahlite mineral.
Ischyodus bifurcatus (Case 1978)
Edaphodon sp.
CRETACEOUS MISSISSIPPI 