Bone
Microstructure of a Cretaceous Ichthyosaur
Victoria B. Lopuchowycz
Department of Earth Sciences. State University of New York at Brockport,
Brockport, New York 14420.
ABSTRACT
The ichthyosaur Platypterygius americanus inhabited the subtropical epicontinental seas of North America. This study examined remains found from the Mowry Shale in eastern Wyoming. Bone microstructure has been used as an indication of ecology, but this is the first study to apply this technique to an ichthyosaur. Through the use of thin-sections, variations in bone microstructure and porosity were examined. In both specimens 1 and 2 the paddle bone was 10% less porous than the vertebra. In specimen 3 the limb was 18% less porous than the paddle bone. Porosity increased from limb, to paddle, to vertebra. By comparing paddle bones among individuals porosity increased from specimen 1, to specimen 2, and was the largest for specimen 3. Thus there appears to be a large variation in porosity among individuals and in different bones from the same individual. Platypterygius americanus had a bone porosity that varied between 46% to 64%, implying that it frequented the deeper portion of the water column.
Table of Contents:
1. Introduction
2. Methods
5. Conclusions
7. References