We argue that the proliferation of collagen-degrading enzymes imparts a major, non-uniform, and irreversible bias upon the exceptional fossil record of animal life. 🧪 (7/8)

This massively restricts the window of time in which fossilization processes can stabilise soft tissues before they fully decompose—leading to fewer exceptional fossils, and lower-quality preservation of soft tissues towards the modern day! 🧪 (6/8)

In the modern day, however, many obligately aerobic microbes (and even some cyanobacteria) possess the ability to degrade collagen. As such, decomposition of collagen can begin immediately after death, or even in life! 🧪 (5/8)

Our results reveal that, before the Phanerozoic, most degradation of collagen likely occurred under anoxic conditions. As these conditions could take substantial time to establish, the onset of collagen decomposition would be delayed—allowing for more time for the carcass to fossilize. 🧪 (4/8)

By exploring how—and when—collagen-degrading enzymes proliferated in microbes, we were able to identify transitions in how collagen decomposed over time. We found clear evidence of collagenases proliferating into oxygen-tolerant microbes in concert with early animal evolution. 🧪 (3/8)

Collagen provides animal tissues with structural integrity, and is a major component of the extracellular matrix. As such, the timing of collagen degradation exerts a considerable constraint on when soft tissues lose integrity, decreasing the likelihood of exceptional preservation. 🧪 (2/8)

🚨Cover reveal🚨: My first non-academic book: How to Find a Martian: A Fossil Hunter's Guide to the Red Planet. Published Spring 2027 by @oneworldbooks.bsky.social (UK/Ireland/Commonwealth, this cover) and @uchicagopress.bsky.social (North America, other cover). 100% human-authored!