Description: This plaque shows a pair of predatory animals from the Middle Cambrian Burgess Shale. Leanchoilia superlata is an unusual arthropod, a member of a group of “great appendage arthropods” known as opabinids after the bizarre Opabinia from the Burgess. It is possibly also known from Utah and Greenland, and has an older relative Leanchoilia illecebrosa found in the Chengjiang Biota of China (see my other offerings). This wonderful example shows incredible detail for a specimen more than a HALF BILLION years of age. Notice the upturned “snout,” the sweeping appendages, body segments, and a hint of the gut trace as well as the gill filaments of the biramous swimming appendages. Coming from the famous Burgess Shale Fauna, this is a highly-desirable member which will make a fine addition to any collection of Cambrian Explosion fossils. It is also quite rare: for each 1000 Burgess specimens only 2 are Leanchoilia; even fewer are as complete as this excellent example.

The second specimen is a member of the Burgess Shale priapulid fauna known as Ottoia prolofica. It is divided into an anterior proboscis and a posterior trunk region. The proboscis is seen here everted, with the scalids (hook-like spines) which it presumably used to capture prey showing. It is known to be a carnivore as examples have been found with several members of the hyolithid Haplophrentis found in the gut. It is sometimes found in a U-shaped orientation, presumably in its life pose (see artist’s rendering). It is not believed to be closely related to any other priapulid, and thus has been assigned to its own family, the Ottoidae. The contrast between the specimens and the matrix has been enhanced by a chemical process that removed some of the matrix overburden. I have included a “before” photo so you can see the difference such treatment makes. Since the specimen is typically covered with resistant mica and is composed of the carbonized remains of the animal, it is inert to the treatment. The result you see here is ALL NATURAL. There has been NO PAINT added to bring out detail. An example such as this showing both specimens in association is a rare one indeed. This one would form the centerpiece of any collection, institutional or private Since the location is now a World Heritage site only specimens from old collections such as this are available.