Description: A fine example of the Order Elllimmichthyformes, Family Ellimmichthydae, Diplomystus birdi was a precursor to Diplomystus dentatus, a well-known fish of the Eocene Green River deposits of Wyoming. This meant that this particular genus lasted for well over 45 million years. It became extinct during the Miocene. The upper right shows a Carpopenaeus shrimp (29 mm as exposed); more of the posterior portion of this specimen is probably still covered by matrix.