Enigmatic Horodyskia williamsi from Precambrian Australia
of the Multicellular Fossils
Time: Mesoproterozoic (1.4 Billion years ago)
mm = 1 inch): Each individual is some 2 mm across. Cluster is 60
mm across on a 60 mm by 115 mm matrix
Backdoor Formation, Western Australia
Some 30 years ago the late Robert J Horodyski discovered what
he termed “problematic bedding plane markings” in
Precambrian deposits in Glacier National Park of Montana. These
were later found to be the remains of what are currently the
oldest known multicellular organisms named Horodyskia moniliformis
in his honor. In addition to those found at Glacier National
Park, this species found in Australia is also known to science.
Horodyski called them a string of beads” a most apt description.
They appear to have been attached by a stolon (the “string”)
and had a regular position along the chain. Given the presumed
nutrient-poor water in which they lived they are thought to have
been photosynthetic like the stromatolites. Here is a chance
to obtain what is currently believed to be the earliest of multicellular
organisms to have colonized the planet. This sinuous example
is the largest I have had.
Smithsonian Institution Press Contributions to Paleontology,
no 94, 202.