They remained unidentified until we showed them to J.D. Stewart of the Los Angeles County Museum of Natural History. The two semi-circular shapes are the hinge points for the lower jaw of the plesiosaur, indicating another possible 'detachable' part that was carried off by a shark. This image is copyright by Dan Varner, and may not be used in any form without his written permission. Pam found this specimen in 1992 while the rest of us were working on the New Jersey State Museum Alzadasaurus. They walked up the hill for a look, and within ten minutes, she picked up a small paddle bone, and found her first plesiosaur coming out of a concretion.
Scale is six inches.
In juvenile plesiosaurs, the limb bones were growing rapidly and the joints were composed primarily of cartilage. Note the lack of articular surfaces on the ends of this bone compared to some of the adult limb bones shown above. While plesiosaurs in general are not well documented from the lower Smoky Hill Chalk, there are occasional remains that show they were there in small numbers. Paleo-life art by Peter Von Sholly. Copyright 2001 by Peter Von Sholly.