RARE Anomalocaris Oral Disc from Cambrian Utah

Description: This is the oral disc of the “Terror Of The Cambrian”, Anomalocaris saron, seen here in the first example I have had. The members of this group of enigmatic creatures are known from Asia, Australia, Europe, and North America, and are thought by many to be closely allied with the Arthropda, a position not held by all researchers. Several have been described from Utah, notably a 50 mm partial specimen of A nathorsti from the Marjum Formation, but they are far more rare than those from Chengjiang or the Burgess Shale. Many examples of Elrathia have been found with bite marks, most typically on the right side, which are thought to have been the result of an abortive attack by this Cambrian raider. Photography of what is essentially a black impression on a black matrix is not easy; I have included a negative photo that might help you to discern the “pineapple slice” appearance of the disk. This is the first example I have had from the Spence Shale, and I do not expect it will remain posted for long.