Fetid Fish Revise Understanding of Fossil Formation

This study's findings raises important questions regarding just how "primitive" the early ancestors of vertebrates were 500 million years ago.

Three rotting Amphioxus heads.
A sequence of images showing how the characteristic features of the body of amphioxus, a close living relative of vertebrates, change during decay. Colours are caused by interference between the experimental equipment and the light illuminating the specimens. (Credit: Mark Purnell, Rob Sansom, Sarah Gabbott, University of Leicester / doi:10.1038/nature08745)

How do you know what something looks like when you’ve never seen it before? This is the question that paleontologists deal with every day: describing the appearance of ancient animals based on incomplete information gathered from small fossilized fragments of those animals. As we will learn in this “blast from the past” (in more ways than one), paleontologists also use this incomplete information about physical appearances to build family trees that describe the evolution of these animals.