Final answer:
Stingrays and spotted ratfish are examples of dorsalventrally flattened fish, which are part of the cartilaginous fish group with skeletons made of cartilage.
Step-by-step explanation:
Two examples of dorsalventrally flattened fish are the stingray and the spotted ratfish. The stingray is often seen blending into the sandy ocean floor, and it relies on its camouflage for protection and hunting. The spotted ratfish, or chimaera, has a unique body shape with a diphycercal tail and lacks the typical scales found on many other fish. Both stingrays and ratfish belong to the group of cartilaginous fish, which have skeletons made of cartilage instead of bone. These fish are known for their relatively large brains and problem-solving abilities, and they lack a swim bladder, instead using muscular fins to create lift and stay afloat.