[D] Mamenchisaurus [sG]
Jurassic Late Oxfordian
Saurischia Sauropodomorpha Sauropoda Euhelopodidae
Genus - Skull
Mamenchisaurus (Young, 1954) > Mamenchisaurus constructus (Young, 1954) > Mamenchisaurus hochuanensis (Young& Chao, 1972) > Mamenchisaurus sinocanadorum (Russell & Zheng, 1994) > Mamenchisaurus youngi (Pi, Ouyang & Ye, 1996) > Mamenchisaurus anyuensis (He, Yang, Cai, Li and Liu Z., 1996) > Mamenchisaurus jingyanensis (Zhang, Li. & Zeng, 1998)
Mamenschisaurus represents another abarrant line of diplodocids. It is known from the almost complete vertebral column and many of the limb and girdle bones, but the skull and much of the feet are lacking.
The cervical vertebrae are moderately elongate, which, when coupled with their increased number, produced the longest neck of any animal ever. Some individuals may have had necks 15m (49ft) long. Yet the neck was comparatively light: some areas of bone were eggshall thin. Each cervical vertebrae (neck bone) had two rod-like ribs to stiffen the neck, as in other sauropods.
Some features of the spine are reminiscent of Diplodocus. The total number of caudals and wheter the tail ends in a whipflash are not known. The chevrons begin to fork at caudal 12, and the later chevrons show that the extreme fore and aft expansion is developed more strongly than in any other genus other than in Diplodocus itself.
Skull fragments found in the 1980s suggest Mamenschisaurus had a taller, blunter snout than Diplodocus, and teeth that were sturdier and more spoon-shaped. Discoveries of fragmentary Mamenchisaurus skull material indicate that the teeth were spatulate, not rod-shaped, which calls into question its reconstruction as a diplodocid. It now seems as if its skull had a taller, blunter snout, as in Omeisaurus, and that Mamenchisaurus should be classified as a euhelopodid.