SI Dataset - Steart et al 2023 - New evidence of the architecture and affinity of fossil trees from the Jurassic Period Purbeck Forests of southern England

This dataset is part of the published paper: New evidence of the architecture and affinity of fossil trees from the Jurassic Purbeck Forest of southern England

Authored by: David C. Steart¹, John Needham², Christine Strullu-Derrien^3,4, Marc Philippe⁵, Jonathan Krieger⁶, Lil Stevens³, Alan R. T. Spencer. ^3,7, Peta A. Hayes³, and Paul Kenrick^3*.

¹ School of Agriculture, Biomedicine & Environment, LaTrobe University, Bundoora, Victoria, 3086, Australia
² Gare de Planès, 26 Chemin de la Gare, 66210 Planès, France
³ Science Group, Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom
⁴ Institut de Systématique, Evolution, Biodiversité, UMR 7205, Muséum National d’Histoire Naturelle, 75005 Paris, France
⁵ Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France
⁶ Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, United Kingdom
⁷ Department of Earth Sciences and Engineering, Imperial College London, London, United Kingdom

Abstract:

We document the habit and affinity of the most complete Mesozoic Era tree to be excavated in the UK. The fossil was found in situ in a palaeosol of the Upper Jurassic Purbeck Group of southern England (Tithonian: ca. 150–145 million years). It comprises over 100 permineralized (silicified) pieces that represent a rooted stump and fallen trunk, together weighing more than two tonnes. This exceptional specimen was excavated in a manner that retained the original associations among its parts, providing a unique insight into the overall habit and mode of growth. A laser scanning approach was used to facilitate the investigation, producing the largest 3D reconstruction of a plant fossil. Anatomical details reveal that the wood belongs to the fossil-genus Agathoxylon. Despite an estimated growth age of more than 200 years, the tree was of modest size, not greatly exceeding 12m in height. The main trunk bifurcated, developing into a decurrent, spreading crown. Its habit differed significantly from most modern arborescent conifers, which have pole-like central trunks and narrow, conical crowns, and from known growth forms in the Cheirolepidiaceae, an important extinct group of Mesozoic conifers. These findings extend our knowledge of the growth architecture of Jurassic conifers, which were prominent and diverse elements of seasonally arid, low to mid-latitude coastal communities during the Late Mesozoic.

Digital assets in repository:

• stump.xov [44.3 MB] and tree_all_parts.xov [262.4 MB] - original digital scan data created by the Creaform VIUScan™ and accompanying VXelements™ which underwent final processing in Rapidform™ XOR. Old versions of the free to use Rapidform EXPLORER can open these files.
• tree_all_parts.stl [4.1 GB] - high resolution triangle mesh of the tree in STL format.
• tree_all_parts.blend [864.3 MB] - Blender v3.2.1 (https://www.blender.org/) file with the imported tree_all_parts.stl mesh. 
• tree_all_parts.mp4 [19.5 MB] - MP4 video 1920x1080px showing the 3D tree_all_parts.stl mesh as a ray-traced animation.
• bennettitalean_trunk.stl [16.5 MB] - triangle mesh of the bennettitalean trunk in STL format.