Animation showing the relationships between a fossil shell (right) and an external mold (left) of the ammonoid cephalopod Gunnarites sp. from the Cretaceous Lopez de Bertodano Formation of Snow Hill Island, Antarctica (PRI 61543). Specimen is from the collections of the [Paleontological Research Institution](http://www.priweb.org), Ithaca, New York. Diameter of specimen (not including surrounding rock) is approximately 9 cm. Model by Emily Hauf. See also: https://sketchfab.com/models/aa818d5b7bc54fe288f81aa72156b816 https://sketchfab.com/3d-models/cephalopod-gunnarites-sp-pri-61543-aa818d5b7bc54fe288f81aa72156b816