Ordovician Fossils

6 Jun 2019

Go to https://phys.org/news/2019-06-rare-fossils-picture-biodiversity-middle.html ... a research paper published in The Science of Nature (2019) DOI:10.1007/s00114-019-1623-z ... 'Soft Bodied Fossils from the Upper Valongo Formation of northern Portugal'. More soft tissue fossils. This time from the Ordovician - older by far than the Dinosaur age. The Ordovician in Britain is best associated with seams of coal which infers a catastrophic event (burial of vegetation and trees in order to form coal). To preserve soft bodied tissue requires rapid burial. Whilst the catastrophism inherent in both is largely ignored it is worth while keeping this point in the back of the mind. The soft tissue animals include jellyfish, Wiwaxiid salerites and arthropod carapace (you will have to look them up yourself). Wiwaxiids are apparently slug like creatures but with a difference - they are armour plated with big spines. In the Plate Tectonics model the Valongo Formation, famous for its trilobites, were part of a shallow sea on the margin of northern Gondwana. The deposit, by the way, is also described as shelly rich with the addition of purely soft tissue creatures such as jellyfish - and slug like molluscs roaming on the ground. Do they mean the sea bed or dry land? If the latter and then this is not purely a shallow sea deposite but may even represent a marine transgression event (hence a mixture of marine and land animals). One would have to read the article in more detail rather than just the press release provided by PhysOrg.

One point - the fossils are dated to mid Ordovician, prior to the big extinction event at the end of that period.