SPECTACULAR Museum Burgess Shale Leanchoilia
Great Appendage Arthropoda with Vauxia Poriferan

Description: Leanchoilia superlata is an unusual arthropod found in the Burgess Shale Fauna of British Columbia. It is 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). The contrast between the specimen 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. 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 gut trace as well as the gill filaments of the biramous swimming appendages.

The smaller fossil to the lower left is an unbranched example of the sponge Vauxia. Unlike all other Burgess sponges, this one is composed only of a spongin-like material with no spicules. The fibers that made up the skeleton are fused into a net affording a tough structure that preserved well. If you look closely, you can see the pores present with which the sponge took up water to filter out the particulates upon which it fed. 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. Since the location is now a World Heritage site only specimens from old collections such as this are available.