Strange creatures from Seymour Island

When you look at an animal as strange as this, you probably think of a lot of questions — what kind of animal is it? Why is it shaped like this? How did it move around? Scientists who study the Zinsmeister Collection are asking these same questions. These creatures are called Ammonoids, and they are an excellent example of how the Zinsmeister Collection is helping to track evolutionary changes in a group of animals over time. By examining different characteristics of these fossils — their shapes, sizes, patterns, and even how many of them are found — we can measure changes and see how a species evolves.

Looking at the evolution of certain animals can also help to define certain periods of geologic time. For example, the change in shell shape of a particular family of gastropods (which includes Antarctodarwinella ellioti, pictured here) over time is what is used to draw boundaries between layers of rock laid down at different times during the Eocene period.

Read more about the heteromorph ammonoid here! (PDF)

This amazing creature, a heteromorph ammonoid, was featured in the Summer 2010 issue of American paleontologist, a magazine published by the PRI and Museum of the Earth.

Antarctodarwinella ellioti is an example of an index fossil — finding this snail helps determine the age of the surrounding rocks!