This is Mazon Monday post #128. What's your favorite Mazon Creek fossil? Tell us at email:[email protected].
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Fossils are often found in concretions, which form within sediment as a local accumulation of matter. In the case of Mazon Creek, these concretions consist of Iron Carbonate and quite often form around some central organic material. The typical ovoid shape has an aesthetic all its own. Inside these concretions, one can find fossils of anything from plant material, to various fauna like shrimp, fish, insects, and even jellyfish. As you are probably aware, these fossils can be stunningly beautiful. One fairly common fossil, which isn't mentioned often, is a type of trace fossil called a coprolite. Coprolites are fossilized feces AKA dung. They were first described by William Buckland in 1829, which seems fitting as he claimed he wanted to "eat his way through the animal kingdom". Noting at some point that "the most distasteful items were mole and bluebottle flies".
Recently, some researchers from Curtain University in Perth, Western Australia published a paper called "Fossil Biomarkers and Biosignatures Preserved in Coprolites Reveal Carnivorous Diets in the Carboniferous Mazon Creek Ecosystem" in the journal Biology. Interestingly, Amy Elson, who works with the lead author Madison Tripp, visited the Field Museum back in August 2022 and ESCONI took her to visit the Pit 11 and Braceville Spoil Pile localities. Amy is on the right collecting from the Braceville Spoil Pile. She collected concretions and surrounding shale for further research.
ESCONI members Rich Holm and Jeremy Zimmerman were part of the Field Museum field trip that included Amy Elson, Paul Mayer Field Museum Collections Manager of Fossil Invertebrates, and a few of his interns.
The coprolite sample used in the study.
A summary of the paper can be found on Phys.org.
Curtin researchers have analyzed organic molecules preserved within 306-million-year-old fossilized animal feces (coprolite) and unlocked a wealth of information about the diets of long-extinct animals and prehistoric ecosystems. Their study is published in Biology.
Lead author Ph.D. student Madison Tripp from Curtin's WA-Organic and Isotope Geochemistry Center (WA-OIGC) said the research had revealed important biomolecular information that, despite being millions of years old, remained intact at a well-preserved fossil site.
"The samples, collected from Mazon Creek in Illinois and supplied by Field Museum Chicago, are the first coprolites of the 60-million-year-spanning Carboniferous age to be studied for organic molecules," Tripp said.
"By studying these molecules preserved inside the fossilized feces samples, we found fascinating dietary information about an unidentifiable extinct animal from Earth's distant past—showing that the animal was a meat-eater or on a predominantly carnivorous diet.
"Molecular analysis of the feces or coprolites showed two clear indicators the animal was carnivorous. One was the high proportion of a variety of molecules derived from cholesterol, which is present in most animals, and the other is a distinct lack of plant-derived biomarkers."
"Interpreting the diets of extinct animals through the biomolecular analysis of coprolites is important for studying ancient environments and ecosystems, which may have implications for understanding, our current ecosystems."
Research co-author ARC Laureate Fellow, John Curtin Distinguished Professor Kliti Grice, Director of WA-OIGC, who was this week named Scientist of the Year at the 2022 Premier's Science Awards, said the research highlighted the significance of exceptionally preserved fossil sites, such as Mazon Creek.
