Mamenchisaurus

Name:

Mamenchisaurus (Greek for "Mamenxi lizard"); pronounced ma-MEN-chih-SORE-us

Habitat:

Forests and plains of Asia

Historical Period:

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Anchisaurus

By Bob Strauss

Late Jurassic (160-145 million years ago)

Size and Weight:

Up to 115 feet long and 50-75 tons

Diet:

Plants

Distinguishing Characteristics:

Unusually long neck, composed of 19 elongated vertebrate; long, whiplike tail

About Mamenchisaurus

If it hadn't been named after the province of China where it was discovered, in 1952, Mamenchisaurus might better have been called "Neckosaurus." This sauropod (the family of gigantic, herbivorous, elephant-legged dinosaurs that dominated the late Jurassic period) wasn't quite as thickly built as more famous cousins like Apatosaurus or Argentinosaurus, but it possessed the most impressive neck of any dinosaur of its kind--over 35 feet long, composed of no less than nineteen huge, elongated vertebrae (the most of any sauropods with the exception of Supersaurus and Sauroposeidon).

With such a long neck, you might assume that Mamenchisaurus subsisted on the uppermost leaves of tall trees. However, some paleontologists believe that this dinosaur, and other sauropods like it, was incapable of holding its neck to its full vertical position, and instead swept it back and forth close to the ground, like the hose of a giant vacuum cleaner, as it feasted on low-lying shrubbery. This controversy is closely tied to the warm-blooded/cold-blooded dinosaur debate: it's difficult to imagine a cold-blooded Mamenchisaurus having a robust enough metabolism (or a strong enough heart) to enable it to pump blood 35 feet straight up into the air, but a warm-blooded Mamenchisaurus presents its own set of problems (including the prospect that this plant-eater would literally cook itself from the inside out).

There are currently seven identified Mamenchisaurus species, some of which may fall by the wayside as more research is conducted on this dinosaur. The type species, M. constructus, which was discovered in China by a highway construction crew, is represented by a 43-foot-long partial skeleton; M. anyuensis was at least 69 feet long; M. hochuanensis, 72 feet long; M. jingyanensis, up to 85 feet long; M. sinocanadorum, up to 115 feet long; and M. youngi, a relatively runty 52 feet long; a seventh species. M. fuxiensis, may not be a Mamenchisaurus at all but a related genus of sauropod (provisionally named Zigongosaurus). Mamenchisaurus was closely related to other long-necked Asian sauropods, including Omeisaurus and Shunosaurus.