A new species of fossil from 444 million years ago that has perfectly preserved insides has been affectionately named "Sue" ...

They were spiral-shelled creatures ... geological structure — this makes ammonites index fossils. Ammonites are primarily found in marine sedimentary deposits, where they were once abundant ...

Their larvae parasitize various marine invertebrates ... They observed the fossil to have a spiral-like, folded structure on the inside which stretches along its length, reaching towards its ...

This is based on the knowledge that some modern fishes such as coelacanths and sharks have spiral-shaped intestines. It is difficult to find out exactly what animal produced a now-coprolite, however, ...

Earth once hosted more than 10,000 species of these ancient marine predators. Find out how they lived, when they vanished, and how much we know about them today. Based on the fossil record ...