Mamenchisaurus neck posture

[GSP1954@aol.com]

Recently a Sino newspaper article was posted mentioning some Chinese 
researchers analysis that Mamenchisaurus could not lift its neck and head far 
above 
heart level (anyone know if there is a technical study out on this?). This is 
perplexing in that the quarry map of a complete Mamenchisaurus in Pi et al 1996 
shows the apparently articulated neck flexed dorsally so that the head is far 
above the back. This is a death pose, but there is no a-priori reason to 
presume the neck could not approach or match the same position in life in the 
manner living people and other animals can tilt their head back into a death 
pose. 
The two giraffe necks I have articulated articulated in a sub horizontal 
posture, but giraffe's can lift their necks vertically. Also, the quarry photo 
of 
the  Mamenchisaurus in Yang et al 1972 shows the neck kinked up at the base 
even though the rest of the neck was not dorso-flexed, further evidence that 
the 
head was often carried well above heart level. 

If as some argue blood pressure issues kept sauropods from elevating their 
heads well above heart level then they would have strong stops in the cervicals 
to keep the head from being raised so high that circulatory disaster would 
ensue. In reality only the short necked dicraeosaurs had such necks, all long 
necked sauropods had the ability to elevate the head many meters above the 
heart 
even when quadrupedal - even more so when rearing which many sauropods were 
specialized for doing. Ergo most sauropods had the ability to stand far taller 
than any known mammal, which in turn should have required oversized, super 
pressure and hard working hearts that would have boosted metabolic rates well 
above reptilian level. 

GPaul