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Re: dogma of tree feeding sauropods



Greg Paul wrote:

>The animals that do have forked chevrons are the giant ground sloths, 
>which very probably used their tails as props when they feed on two 
>legs. Sauropods probably did the same thing. 

I do not accept the modern dogma that all sauropods were tree feeders. 
1) The "skid" chevrons occur in sauropods with very long tails, e.g., 
diplodocids. In the recent remounting of the Diplodocus at the Denver 
Museum of Natural History, I discovered that the skid chevrons 
practically touch one another. I suspect that functionally the "skids" 
were bound with ligaments in order to keep the tail relatively stiff 
and off the ground without the use of muscles.   2) The fossil evidence 
for trees so tall that sauropods needed to rear up is very piss poor. 
There are some large logs in the Morrison, but few indicate 100+ ft 
tall trees. Considering that the dominant vegetation was ferns (over 
200 species based on pollen, Litwin, pers. com.), I see no need to 
invoke sauropods rearing up to feed on 100+ ft trees. 3) the broad, 
squared muzzle of diplodocids is more similar to that seen in the hippo 
and white rhino, both of wich are low ground cover croppers. It is not 
at all like the rounded muzzle of more selective mammalian herbivores 
and which is also seen in some sauropods (e.g. camarasaurids). 4) The 
long neck of diplodocids would allow them to crop a larger area of 
ferns, etc. in order to fuel their large mass. 5) The neck of 
camarasaurids does indeed angle shapely upwards due to the wedge shaped 
1st dorsal or last cervical (i.e., it is longer along the bottom of the 
centrum than across the top). This sauropod was most likely a tree 
feeder (perhaps tree ferns when young, conifers when adults). 

Kenneth Carpenter
Dept. of Earth Sciences
Denver Museum of Natural History
2001 Colorado Blvd.
Denver, CO 80205
crpntr@ix.netcom.com