Overview

ammonite


Show Summary Details

Quick Reference

An extinct aquatic mollusc of the class Cephalopoda. Ammonites were abundant in the Mesozoic era (225–65 million years ago) and are commonly found as fossils in rock strata of that time, being used as index fossils for the Jurassic period. They were characterized by a coiled shell divided into many chambers, which acted as a buoyancy aid. The external suture lines on these shells increased in complexity with the advance of the group.

Subjects: Biological Sciences.


Reference entries

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.