Saurichthys

The saurichthys (gen. Saurichthys) is a chondrostean fish that lived in the Triassic and Lower Jurassic (between 235 and 200 million years ago). Its remains have been found in many parts of the world (Europe, China, Madagascar, South Africa, Russia, Greenland, Spitzbergen, North America and Australia). With a long, tapered body, this fish is considered to be one of the most widespread predators of the Triassic seas.
The slender, elongated head, armed with conical teeth, was equipped with decidedly light dermal bones, such that the animal's weight was reduced. The entire body of the saurichthyte was structured in a particularly hydrodynamic manner: the anal and dorsal fins were set far back, close to the caudal fin, so as to take full advantage of the propulsive thrust of the tail. The internal organs were most likely placed in the anterior part of the body, while the posterior part was almost entirely occupied by powerful propulsive muscles.
Unlike many contemporary fishes, the saurichthyid lacked the thick coating of ganoid scales, which were reduced to four longitudinal rows along the back.