Mamenchisaurus constructus, M. hochuanensis, M. sinocanadorum, M. youngi, M. anyuensis, M. jingyanensis, M. yunnanensis
Source: http://nature.ca/notebooks/english/mamenchi_p1.htm
Name: Mamenchisaurus constructus, M. hochuanensis, M. sinocanadorum, M. youngi, M. anyuensis, M. jingyanensis, M. yunnanensis
Name Meaning: Mamenxi Lizard
First Described: 1954
Described By: Young
Classification: Saurischia, Eusarischia, Sauropodomorpha, Plateosauria, Massopoda, Sauropodiformes, Anchisauria, Sauropoda, Gravisauria, Eusauropoda, Mamenchisauridae
My Fourth Favorite Dinosaur
Mamenchisaurus is one of those dinosaurs that you just feel is trying to hard to be spectacular. The largest species, M. sinocanadorum, was up to 35 meters long, and 15 meters high. Overall, though the genus ranges between 13 and 35 meters long - not something to be taken lightly. It lived in the Late Jurassic period, between 160 to 145 million years ago from the Oxfordian to Tithonian ages, and is known from several partial individuals. When I was little, a documentary on the Discovery Channel (I can't seem to find it now,) compared the animal to a suspension bridge, and nothing could be a more accurate description
Source: http://dinosaurs.wikia.com/wiki/File:Mamenchisaurus.jpg
It lived in China, and has been found in a variety of places there, first in Sichuan. Until the discovery of Supersaurus, the original length of the neck (31 feet) was the longest one known. Sauroposeidon now holds the title for longest neck at 36.9 to 39.4 feet long, but Mamenchisaurus still is quite the contender. The species M. hochuanensis was described as having tall neural spines at the tip of the tail, which could have formed a weapon such as a tail club, or a sensory organ. Mamenchisaurus' neck was just as long as its tail and body combine, allowing it to sweep its neck around to feed on a wide area of vegetation. Mamenchisaurus just had to reach a green acre and chomp from one place, not moving its body at all.
Sources:
http://en.wikipedia.org/wiki/Mamenchisaurus
http://www.prehistoric-wildlife.com/species/m/mamenchisaurus.html
Shout out goes to jakebabel!