Science, Tech, Math › Animals & Nature Nothosaurus Share Flipboard Email Print Nothosaurus (Berlin Natural History Museum). Animals & Nature Dinosaurs Marine Reptiles Basics Paleontologists Carnivores Dinosaurs & Birds Herbivores Prehistoric Mammals Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Marine Life Forestry Evolution View More By Bob Strauss Science Writer B.S., Cornell University Bob Strauss is a science writer and the author of several books, including "The Big Book of What, How and Why" and "A Field Guide to the Dinosaurs of North America." our editorial process Bob Strauss Updated March 17, 2017 Name: Nothosaurus (Greek for "false lizard"); pronounced NO-tho-SORE-us Habitat: Oceans worldwide Historical Period: Triassic (250-200 million years ago) Size and Weight: About 10 feet long and 150-200 pounds Diet: Fish and crustaceans Distinguishing Characteristics: Long, tapered body; narrow head with numerous teeth; semi-aquatic lifestyle About Nothosaurus With its webbed front and back feet, flexible knees and ankles, and long neck and tapered body--not to mention its numerous teeth--Nothosaurus was a formidable marine reptile that prospered across the nearly 50 million years of the Triassic period. Because it bears a superficial resemblance to modern seals, paleontologists speculate that Nothosaurus may have spent at least some of its time on land; it's clear that this vertebrate breathed air, as evidenced by the two nostrils on the top end of its snout, and although it was undoubtedly a sleek swimmer, it wasn't as well adapted to a full-time aquatic lifestyle as later pliosaurs and plesiosaurs like Cryptoclidus and Elasmosaurus. (Nothosaurus is the best known of the family of marine reptiles known as nothosaurs; another well-attested genus is Lariosaurus.) Although it's not widely known to the general public, Nothosaurus is one of the most important marine reptiles in the fossil record. There are over a dozen named species of this deep-sea predator, ranging from the type species (N. mirabilis, erected in 1834) to N. zhangi, erected in 2014, and it apparently had a worldwide distribution during the Triassic period, with fossil specimens discovered as far afield as western Europe, northern Africa and eastern Asia. There is also speculation that Nothosaurus, or a closely related genus of nothosaur, was the distant ancestor of the giant plesiosaurs Liopleurodon and Cryptoclidus, which were an order of magnitude bigger and more dangerous!