ABSTRACT: Dinosaur Eggs

Karl F. Hirsch

Identification and classification of fossil eggshell is based on the knowledge of and comparison with modern eggshell. Modern amniote eggs can be divided in three types: soft-, pliable-, and rigid-shelled eggs. In the rigid-shelled eggs, the ones that are most likely to be fossilized, we distinguish four basic structural organizations: geckonoid, testudoid, crocodiloid, and ornithoid. All of these groups have been traced back into the Mesozoic.

Identification and classification of eggs of extinct species are still somewhat problematic and fluid. Older systems, outdated by the latest, but by no means the last, scientific findings are being replaced by a more suitable system. For dinosaur eggs two basic organizational

groups, the dinosauroid-spherulitic and dinosauroid prismatic group, have been established, although some dinosaur eggs fall into the ratite morphotype of the ornithoid group.

Eggshells, although traces, can be a valuable tool in interpreting environmental conditions, and in some cases even the social behavior of the egg-laying animals.

AAPG Search and Discovery Article #91002©1990 AAPG Rocky Mountain Section Meeting, Denver, Colorado, September 16-19, 1990