Two recent research papers demonstrate the contribution that Scotland’s geology continues to make to understanding evolution and extinction.
The world’s oldest “bug” – a fossil millipede from the island of Kerrera
New calculations of the age of key sedimentary rocks at two sites in Scotland have clarified the timescales of the change from lake margin communities to the much more complex forest environments of the Devonian period. It only took 40 million years for this transition, a much shorter timescale that molecular clock calculations had suggested.
The new research caculates that lake deposits on the island of Kerrara, which contain a fossil millipede, are 425 million years old; older than a previous record, of the fossil millipede Pneumodesmus newmani that was found at Cowie near Stonehaven by Mike Newman, a bus driver and amateur palaeontologist, now thought to be 414 million years old.
Read the full article (open access) by M. E. Brookfield, E. J. Catlos, S. E. Suarez of The University of Texas at Austin in Historical Biology.
Further information about Pneumodesmus newmani from Cowie (wikipedia).
The late Ordovician mass extinction linked to volcanic activity
Just 20 million years earlier, life in the oceans had suffered a significant mass extinction with the loss of 85% of species. This late Ordovician mass extinction was thought to have a different origin than other mass extinctions in geological history, that are associated with global warming related to large-scale volcanic activity. Recent research of the rocks at Dob’s Linn in the Southern Uplands has changed that, by detected evidence of a spike in mercury levels, which combine with other evidence to suggest that sustained volcanic activity and oceanic anoxia.
Read the full article (open access) by David Bond (University of Hull) and Stephen Grasby (Geological Survey of Canada) Late Ordovician mass extinction caused by volcanism, warming, and anoxia, not cooling and glaciation, Geology 2020.