Scientists from the Department of Earth Sciences at Royal Holloway, University of London have found the oldest fossils of the familiar pine tree that dominates Northern Hemisphere forests today.
The 140-million-year-old fossils (dating from the Cretaceous ‘Age of the Dinosaurs’) are exquisitely preserved as charcoal, the result of burning in wildfires. The fossils suggest that pines co-evolved with fire at a time when oxygen levels in the atmosphere were much higher and forests were especially flammable. More.
From Dispatch Tribunal:
The 7mm long fossil pushes back the date of pine tree origin by 11 million years as a previous fossil was dated 129 million years old, making the fossils discovered from Windsor as the oldest known fossils of pine trees.
The fossils that were discovered were charred meaning that they were preserved as a charcoal, the result of burning in wildfires. … Researchers believe that the pines during the Cretaceous period could have co-evolved with fire at a time when oxygen levels in the atmosphere were much higher and forests were especially flammable.
See also: Fungus is oldest land fossil at 440 mya So far what’s known: “rope-like structure similar to that of some modern-day fungi”
Stasis: Life goes on but evolution does not happen (or not much, anyway)
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Here’s the abstract:
Pinus (Pinaceae) is a diverse conifer genus that dominates Northern Hemisphere forests today and is noteworthy for its fire-adapted traits. Here we describe the oldest known fossils attributable to the genus from the Lower Cretaceous (Valanginian, ca. 133–140 Ma) part of the Chaswood Formation of Nova Scotia, Canada. Pinus mundayi sp. nov. comprises charred long-shoots, which show a constellation of derived characters including (1) axial resin ducts with thin-walled epithelial cells in the secondary xylem and phloem, (2) fenestriform or pinoid cross-field pits, and (3) helically arranged short-shoots that pass through growth ring boundaries before distally diverging into two separate needle bases. The fossils, which are interpreted as remains of an evergreen two-needle pine, provide a new constraint on timetrees of Pinaceae evolution. Their preservation as charcoal and the occurrence of resin ducts, which produce flammable terpenes in modern pines, show that Pinus has co-occurred with fire since its Mesozoic origin. (paywall) – Howard J. Falcon-Lang, Viola Mages, Margaret Collinson. The oldest Pinus and its preservation by fire. Geology, 2016; G37526.1 DOI: 10.1130/G37526.1