A diagram by Mark Evans which was recently included in an article on the Tetrapod Zoology blog. This is meant to show the possible ranges of vertical motion present in the necks of Cryptoclidus and Muraenosaurus based on fossil remains. Although this would seem to put a damper on the relict plesiosaur hypothesis, the article noted "that cartilage and other soft tissues may have allowed more flexibility than we can predict based on osteology alone." Add to that the SV-POW study which found that fossil reptile forms would most likely hold their necks at elevated angles. Please note that none of the people I cited here agree with the thinking that relict plesiosaurs exist.
And then I added:
Dale Drinnon ...Which is precisely what I have been saying all along, none of these people allow for cartilages. And it is virtually nothing to go from the position at upper right into the standard "Periscope" position (The standard periscope does not include the base of the neck but by its very nature ordinarily only the front 2/3 of the length of the neck)
The more extreme type of perriscope has no forward motion and the body can be assumed to be held vertically in the water, thusly:
There is no reason not to believe that when the Plesiosaur were alive some of them might not have had more flexible necks and if some survived the K-T extinction they couldn't have adapted to cooler waters.
ReplyDeleteSome Plesiosaur fossils have been found in Antarctica and it was a cold climate even then. Please see Scott Mardis' article that I have recently reprinted. PLesiosaurs could tolerate not only freshwater but also icy cold waters and some of them presumably were insulated by blubber.
DeleteThere is also some evidence that Mesozoic marine reptiles, including plesiosaurs, might have been endothermic.
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