Dinosaur eggshells are valuable indicators, both biologically and environmentally. For our research focus, we have decided to determine eggshell thickness in correlation to points on an eggshell and the implications that may result. Two principal problems that we encountered initially were that we had no way to record an accurate measurement of the eggshell width, and that we did not know for certain the orientation of the egg in that there was no apparent way to tell which point on the egg was laid skyward – “up.” We addressed the first issue in the experimental design and the second we hope to address after the data has been collected and analyzed.
In order to measure the thickness of the shell, we have developed a system in which a sewing needle was placed under a microscope and measured with calipers at every millimeter up to five millimeters. While still under the microscope, a pocket knife was used to cut hash marks in the needle at the measured intervals. Colored pencil shavings were then rubbed into the marks so that they were more apparent. Having done so we are able to place the needle parallel to the plane of the eggshell cross-section and use the hash marks to measure the width accurately on a small scale.
We have decided to use thirty points on each egg and so we toook pieces of clay and placed them on the thirty spots deemed best to measure. Each piece of clay is assigned a number and then the egg is photographed. We then uploaded photos to an editing program. The photos are then correlated with the numbers. We take pictures of the egg from all angles and then correlate each of the thirty points with a number. When measured, we record the eggshell thickness at each number.
Upon return to Montana State University, we will use a computer program that will allow us to create a three dimensional image of the egg with the various eggshell thicknesses. Through this, we hope to model a replica of the egg with the correct eggshell thicknesses in the correct places. By doing so, we will then hypothesize the orientation. We plan to test this hypothesis with an actual taphonomic experiment in which eggshells of modern birds will be measured and then correlated to the data gathered on the fossil eggs. — By Josette Wooden Legs and Tyler Bridges.