Supplementary data for: Hydrodynamic insights into the palaeobiology of the Ediacaran rangeomorph Fractofusus misrai

The Ediacaran of Newfoundland preserves some of the oldest complex macroscopic communities several of which are dominated by the fractal-like rangeomorph genus Fractofusus. Here we use computational fluid dynamics and a detailed reconstruction of Fractofusus misrai to document for the first time hydrodynamic phenomena associated with this sediment-reclining organism and its rangeomorph elements that: are relevant to interpreting feeding strategies, explain the recently documented rheotropic growth oblique to currents, and provide insights into their impact on the Ediacaran seafloor. Obliquely oriented Fractofusus are common, likely representing a compromise between maximized aspect ratio and minimization of drag. Flow patterns on the upper surface of Fractofusus are consistent with the collection of dissolved and finely particulate nutrients, as well as gas exchange. Fractofusus produce a long wake downstream, demonstrating that reclining Rangeomorpha had potential to modify sedimentati..., Geometry of Fractofusus misrai The three-dimensional models of F. misrai were created using ZBrush Pixologic, Inc. (https://www.maxon.net/en/zbrush; by R. Nicholls), then post-processed using Rhinoceros 3D v.7 (https://www.rhino3d.com) and Blender v.3.4.1 (https://www.blender.org). The geometry was built as a smoothed three million polygon mesh, capturing three orders of rangeomorph branching. Scaling followed published fossil dimensions, and geometries were oriented according to the statistical clusters in Pérez-Pinedo et al. 2023. Finally, results were analyzed with the post-processing visualization engine Paraview (https://www.paraview.org). Computational Fluid dynamics (CFD) Discretization and sensitivity tests were conducted to determine optimal mesh sizes, balancing anatomical resolution with computational efficiency (computing cores, CPU usage; Figs. S1-S2) at which results are independent of the mesh size. Fractofusus misrai geometries, consisting of approximately 300,000 to 500..., , # Supplementary data for: Hydrodynamic insights into the palaeobiology of the Ediacaran rangeomorph Fractofusus misrai [https://doi.org/10.5061/dryad.fxpnvx103](https://doi.org/10.5061/dryad.fxpnvx103) Supplementary materials include: 1) computational fluid dynamics (CFD) results from discretization and sensitivity tests conducted to determine optimal mesh sizes, balancing anatomical resolution with computational efficiency (Figs. S1-S3); 2) CFD simulation results from different sizes of *F.misrai* and general view of streamlines (Figs. S4-S6); 3) CFD simulation results from null models (Fig. S7); 4) flow velocity profile (Fig. S8); 5) all numeric results from CFD simulations (Table S1); 6) the *Fractofusus misrai* geometry; and 7) CFD simulation results. ## Description of the data and file structure Fig. S1-S3 show different mesh sizes for both the flow volume region (FVR) and the *F. misrai* geometry. *Fractofusus misrai* geometries, consisting of approximately 300,000 to 500,000...纽芬兰埃迪卡拉纪地层保存了一批迄今已知最为古老的复杂宏观生物群落，其中多个群落以具有分形特征的rangeomorph类群（Rangeomorpha）下的*Fractofusus*属为优势类群。本研究借助计算流体动力学（Computational Fluid Dynamics, CFD）手段与*Fractofusus misrai*的精细重建模型，首次揭示了这种伏卧于沉积物之上的生物及其rangeomorph类群结构相关的流体动力学现象：这些现象可为解释其摄食策略提供依据，可解释近期报道的、与水流方向斜交的向流生长（rheotropic growth），并为理解其对埃迪卡拉纪海底环境的影响提供新视角。斜向排布的*Fractofusus*个体较为常见，这可能是在最大化长宽比与最小化水流阻力之间寻求平衡的结果。*Fractofusus*上表面的流场模式，与其溶解态与微细颗粒营养物质摄取以及气体交换的生理过程相符。*Fractofusus*下游会形成长距离尾流，表明伏卧型rangeomorph类群具备改造沉积物沉积过程的潜力…… ## *Fractofusus misrai*的几何建模 *F. misrai*的三维模型通过ZBrush Pixologic公司（https://www.maxon.net/en/zbrush；由R. Nicholls制作）创建，随后使用Rhinoceros 3D v.7（https://www.rhino3d.com）与Blender v.3.4.1（https://www.blender.org）进行后处理。该几何模型采用平滑处理后的300万多边形网格构建，完整还原了rangeomorph类群三级分支结构。模型缩放参照已发表的化石尺寸，几何模型的朝向则依据Pérez-Pinedo等人2023年研究中的统计聚类结果确定。最终，借助后处理可视化引擎Paraview（https://www.paraview.org）对计算结果进行分析。 ## 计算流体动力学（CFD） 为确定最优网格尺寸，我们开展了离散化与敏感性测试，在解剖结构分辨率与计算效率（计算核心数、CPU使用率；图S1-S2）之间寻求平衡，确保计算结果不受网格尺寸影响。*Fractofusus misrai*的几何模型网格数约为30万至50万…… # 补充数据：埃迪卡拉纪rangeomorph类群*Fractofusus misrai*古生物学的流体动力学研究启示 [https://doi.org/10.5061/dryad.fxpnvx103](https://doi.org/10.5061/dryad.fxpnvx103) 补充材料包含以下内容：1）用于确定最优网格尺寸的离散化与敏感性测试的计算流体动力学（CFD）结果，兼顾解剖结构分辨率与计算效率（图S1-S3）；2）不同尺寸*F. misrai*模型的CFD模拟结果与流线整体视图（图S4-S6）；3）空模型的CFD模拟结果（图S7）；4）流速剖面（图S8）；5）CFD模拟的全部数值结果（表S1）；6）*Fractofusus misrai*的几何模型；以及7）CFD模拟结果。 ## 数据与文件结构说明 图S1-S3展示了流场区域（FVR）与*F. misrai*几何模型的不同网格尺寸。*Fractofusus misrai*的几何模型网格数约为30万至50万……