By Sarah Boessenecker (@tetrameryx)
Happy Fossil Friday!
Here at CCNHM we have a wonderful collection that was donated from the Mazon Creek Fossil Beds in Illinois. These beds have provided hundreds of specimens of strange organisms that have been exquisitely preserved for over 300 million years!
The beds date from the Pennsylvanian, and form a lagerstätte – a sedimentary structure known for ideal conditions that preserve fossils, especially those of soft-bodied organisms. Anoxic environments prohibited the growth of bacteria and the decomposition of bodies, and as such we can see the structures that would not normally be preserved in other environments.
The name ‘Tullimonstrum’ comes from its first discoverer Francis Tully, with ‘monstrum’ referring to its bizarre bodyplan. It’s so different from anything seen today, scientists have been unable to determine which phylum it should be placed in! While incredibly common from the Mazon Creek fossil site, (gregarium is referring to the abundance of this fossil) it has never been found in any other locality.