Sea Dinosaurs

Genus (length): Description

Ichthyosaurs
Ichthysaurus (2 m / 6.5 ft): A vertical two-lobed tail; long, narrow snout; sharp teeth; ate squid
Mixosaurus (1 m / 3.3 ft): Tail ended in a point; many small teeth; ate fish
Shonisaurus (15 m / 49 ft): Deep, bulky body; long equal-sized flippers; teeth at the front of the jaws only
Temnodontosaurus (9 m / 30 ft): Barrel-shaped body, long snout, and powerful two-lobed tail; the eyes up to 26 cm / 10 inches across; largest eyes of any animal; the eyes surrounded by a ring of thin, overlapping bony plates
Nothosaurs
Ceresiosaurus (4 m / 13 ft): Long, flexible tail, and extra bones in the toes; small head; jaws armed with small, sharp teeth; ate fish
Lauriosaurus (.6 m / 2 ft): Lizardlike shape, with a short neck; short toes with claws on the hind feet; webs on the front feet; amphibious
Nothosaurus (3 m / 10 ft): Five toes on webbed feet; the front legs than the hind legs; spines on the vertebrae; amphibious; ate fish
Pachypleurosaurus (2.5 m / 8 ft): Slim and lizardlike, with paddles like flippers; the head small relative to the body; a range in size among the species; ate fish
Pistosaurus (3 m / 10 ft): Smooth and elliptical flipperlike legs with no toes; a stiff backbone; a small and cylindrical head
Placodus (3 m / 10 ft): Humpbacked; feet webbed and tail flattened; short head; three types of teeth in the jaws; skeleton reinforced; ate mollusks
Plesiosaurs
Cryptoclidus (8 m / 26 ft): Neck up to 2 m / 6.5 ft long; large flippers; long, pointed, and interlocking teeth
Elasmosaurus (14 m / 46 ft): Up to 71 neck vertebrae; neck up to 6 m / 20 ft; narrow head; ate fish
Muraenosaurus (6 m / 20 ft): A long neck, with up to 44 vertebrae; the head 40 cm / 15 inches long; small flippers; a stubby tail; ate fish
Plesiosaurus (3 m / 10 ft): A narrow head and slender neck and tail; two pairs of large, equal-sized paddles; numerous pointed, slightly curved teeth; ate fish
Rhomaleosaurus (7 m / 23 ft): Long neck and large head; two pairs of equal-sized paddles; jaws up to 1 m / 3.3 ft long; large, protruding teeth
Pliosaurs
Kronosaurus (10 m / 33 ft): Head 2.5 m / 8 ft long; larger and heavier than most land-based predators of the Cretaceous Period
Liopleurodon (25 m / 82 ft): Larger than the sperm whale; the jaws hinged up to 4 m / 13 ft from the front; conical teeth up to 30 cm / 12 inches long; possibly live birth instead of eggs; ate any marine animal
Macroplata (6 m / 20 ft): Small head; long neck with 29 vertebrae
Peloneustes (3 m / 10 ft): A large head and a short neck; small teeth; the hind paddles slightly larger than the front paddles; streamlined; ate squid
Pliosaurus (12 m / 40 ft): Skull 2 m / 6.6 ft long; triangular teeth; 20 vertebrae in the neck
Simolestes (6 m / 20 ft): Massive head; blunt jaws; 6 large teeth on the lower jaw; 20 vertebrae in the neck; large paddlelike legs