Updated

Updated · ScienceDaily · Aug 21

Oklahoma Paleontologists Find 450-Million-Year-Old Crinoid Soft Tissue, Only 2nd Such Fossil Known

Updated

Updated · ScienceDaily · Aug 21

Oklahoma Paleontologists Find 450-Million-Year-Old Crinoid Soft Tissue, Only 2nd Such Fossil Known

Q: What mysterious conditions 450 million years ago perfectly vacuum-sealed this ancient sea creature before it could decay?

Scientists do not know the exact single event, but the best explanation is a rare combination of rapid burial, low-oxygen seafloor conditions, very fine sediment, and early mineralization that locked the animal’s soft parts in place before they rotted. In this case, researchers say the crinoid likely died in a calm marine setting and was quickly covered by fine mud. That burial would have cut off scavengers and sharply slowed bacterial decay by limiting oxygen, creating the “natural refrigerator or vacuum-sealer” effect described by University of Oklahoma paleontologist Lena Cole. Evidence from related reporting suggests mineralization was also critical. The soft tissues were likely replicated or coated very early by minerals, possibly pyrite, sometimes called fool’s gold. That process can preserve delicate anatomy by replacing or filming tissue before it collapses and disappears. Some accounts of the fossil’s setting point to deep, still water with little oxygen, conditions known from exceptionally preserved fossil sites. Those conditions do not guarantee soft-tissue preservation, but they make it much more likely by slowing decay long enough for minerals to take over. So the mystery is not fully solved in a dramatic one-off sense; it was probably an extraordinarily lucky convergence of fast burial, oxygen-poor water or sediment, and rapid mineral sealing. That is why this fossil is so rare: millions of crinoid fossils exist, but only two are known to preserve soft tissue.

3 articles · Updated · ScienceDaily · Aug 21

A 450-million-year-old Dendrocrinus simcoensis fossil has been identified as the oldest known crinoid soft-tissue specimen, preserving delicate tube feet that almost never survive fossilization.
Those tissues endured because exceptionally rare conditions acted like a natural refrigerator or vacuum-sealer after death, a level of preservation researchers called one-in-a-million.
The tube feet give scientists a direct clue to how early crinoids fed and occupied reef environments, and comparisons with living crinoids show this ancient species had markedly different anatomy.
That difference could sharpen reconstructions of early Paleozoic oceans and show how crinoid feeding strategies and adaptive evolution changed over hundreds of millions of years.
The fossil had sat for years in Montréal's Musée de paléontologie et de l'évolution, underscoring how museum collections can yield major discoveries long after specimens are collected.