Leanchoilia
superlata
Phylum Arthropoda
Geological
Time: Early Cambrian, (~520 million years ago)
Size: Fossil
is 46 mm overall, plus 20-25 mm appendages
Fossil Site:
Stephen Formation, Burgess Shale, Burgess Pass, British Columbia, Canada
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. 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 seen here.
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