In the thoracic region the intervertebral discs are relatively thin with respect to the vertebral bodies, and together with the presence of the ribs and sternum, their movement is limited.
The spiny dogfish, spurdog, mud shark, or piked dogfish, Squalus acanthias, is one of the best known species of the Squalidae (dogfish) family of sharks, which is part of the Squaliformes order.hile these common names may apply to several species, Squalus acanthias is distinguished by having two spines (one anterior to each dorsal fin) and lacks an anal fin. It is found mostly in shallow waters and further offshore in most parts of the world, especially in temperate waters.
The lionfish (also known as the turkeyfish, tigerfish, dragonfish, scorpionfish, and butterfly cod) is a poisonous spiky fish found in the warmer waters of the western and central Pacific Ocean. The lionfish is a predatory fish hunting small fish, but it's venom is capable of being fatal to larger creatures.