2 10 11 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/e82f884cdfcbcf0c5b784213fb159ef1.png 806574debb150c7909664efee6138600 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/28a1fb886f7368006421315c7a409b82.png 4fbffbc82465ad32a511bfcc397b9055 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/b991dbe90d1c1ca1df17fa3af77186f4.png 3955766fe671a8996a6acde655145297 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Fossils Description An account of the resource <p>Welcome to the fossils section of the website. This is designed to help you learn the different characteristics of each major fossil group so that you are able to distinguish between them.</p> <p>First year students, please refer to the specimens housed in the first year teaching laboratory. There is no substitute for handling the specimens themselves; this website is just an accessory to help you along the way.</p> <p>Animals occupy different environments, have different life habits and lived through different periods in geological time. It is good to be aware of these differences in lifestyle and timing, within and between phyla, classes, orders and families.</p> Physical Object An inanimate, three-dimensional object or substance. Note that digital representations of, or surrogates for, these objects should use Moving Image, Still Image, Text or one of the other types. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource <h2>Ammonoid</h2> Description An account of the resource <h2>Taxonomy</h2> <p>Phylum: Mollusca</p> <p>Class: Cephalopoda</p> <p>Subclass: Ammonoidea</p> <h2>Diagnostic features</h2> <p>[See labelled diagram above]</p> <p>Aragonite shell</p> <p>Septa</p> <p>Suture (different for goniatites, ceratites and ammonites, see second diagram above)</p> <p>Chambers</p> <p>Siphuncle</p> <p>Planispiral shape, involute or evolute (see third diagram on right hand side)</p> <h2>Stratigraphic range</h2> <p>Devonian to Cretaceous</p> <h2>Way of life</h2> <p>Nektonic (jet propelled)</p> <p>Predatory</p> <p>Marine</p> <h2>Common preservation</h2> <p>Internal mould</p> <p><a href="https://www.digitalatlasofancientlife.org/learn/nature-fossil-record/types-of-fossil-preservation/">Learn about types of preservation</a></p> <h2>Advanced notes</h2> <p>Ammonoids could passively remove or add water to chambers via the siphuncle. This allowed them to change their density, and maintain neutral buoyancy with the surrounding seawater. This meant that they were able to swim as efficiently as possible.</p> <p>Ammonoids are extremely good index fossils on account of their diverse morphologies, good preservation potentials and widespread fossil locations.</p> <h2>Specimens</h2> <p><a href="/p1acollections/exhibits/show/ammonoids" target="_blank" rel="noreferrer noopener">Browse ammonoids</a></p> <h2>External links</h2> <p><a href="https://www.youtube.com/watch?v=2ilSDcZAXNM" target="_blank" rel="noreferrer noopener">Telling planispiral fossils apart</a></p> Carboniferous Cretaceous Devonian Jurassic Permian Triassic