Mimetaster hexagonalis
(Gürich, 1931)
Phylum Arthropoda, Class Marrellomorpha
Geological Time: Lower Devonian, Seigenian/Emsian Stage
Size (25.4 mm = 1 inch): Fossils are 20 mm by 27 mm, 20 mm by 9 mm, and 25 mm by 22 mm on a 140 by 135 mm matrix
Fossil Site: Hunsrück Slate, Bundenbach Germany
Code: GF60
Price: Sold
 Description:
Well-preserved specimens of a most unusual marrellamorph known
as Mimetaster. The Hunsruck slate is famous for its fossils, many
of which have pyritization present. Rapid burial and pyritization
was what led to the many wonderful examples of early Devonian life
from the region. The chemistry of the silt was such that low organic
content and high levels of iron and sulfur allowed the pyrite to
diffuse into the tissues rather than be deposited in the sediment.
The mudstones were metamorphosed into slate during the Carboniferous.
The slate was quarried for roofing tiles, and the quarrymen would
save the fossils for later sale. Now that the quarries are no longer
open, future supplies of these wonderfully-preserved benthic organisms
will only come from existing collections. Mimetaster is undoubtedly
the most unusual of Bundenbach organisms. Many have been found
preserved with attached sponges, leading some researchers to believe
the sponges served as a sort of camouflage as in the modern decorator
crab. It is believed that Mimetaster was a social organism, a
fact that seems to be borne out by the association of three of
these
bizarre marrellamorphs on this one plate. |
