Micro-CT analysis of Katian radiolarians from the Malongulli Formation, New South Wales, Australia, and implications for skeletogenesis

A diverse and well-preserved radiolarian assemblage from the Malongulli Formation, New South Wales, Australia contains 13 species representing ten genera and six families. One new genus: Wiradjuri n. gen. is introduced to accommodate pre-Devonian single-shelled entactiniid taxa and one new species: Secuicollacta malongulliensis n. sp. is recorded together with some previously described forms. The micro-structure of the ‘rotasphaerid structure/primary unit’ and the ‘ectopic spicule’ are investigated to validate their roles as fundamental units in the Secuicollactidae together with comprehensive documentation of the previously enigmatic Pseudorotasphaera internal skeleton.
The results of this investigation suggest that, among all radiolarian genera that survived the Late Ordovician Mass Extinction event (LOME) and transitioned into the Silurian, Secuicollacta, Haplotaeniatum, and Palaeoephippium maintained stable body plans during the transition and were more successfully established. The..., MicroCT reconstructions of radiolarians collected from the Upper Ordovician (Katian) Malongulli Formation, NSW, Australia  (33°34'57.58\"S, 148°52'54.06\"E). 
Fossil specimens were scanned using a Zeiss Xradia Versa XRM-500 high-resolution micro-CT scanner at the Julius Kruttschnitt Mineral Research Centre, The University of Queensland. 3D models were generated using Avizo® 9.7 (2020.2 version) volume rendering software., Datafiles can be viewed using any software that will open and run mpg files.,

澳大利亚新南威尔士州马龙古利组（Malongulli Formation）产出一套多样且保存完好的放射虫组合，包含10个属、6个科下的13个物种。本文建立1新属：维拉朱里虫属（Wiradjuri）n. gen.，以容纳泥盆纪前的单壳内射虫科类群；同时报道1新种：Secuicollacta malongulliensis n. sp.，并附带若干已发表的形态类群。本研究针对“旋转球虫结构/基本单元”与“异位骨针”的微观结构展开分析，以验证其作为Secuicollactidae科基本构造单元的合理性，并对此前存疑的假旋转球虫属（Pseudorotasphaera）的内骨骼进行全面记述。
本研究结果表明，在所有经历晚奥陶世大灭绝事件（Late Ordovician Mass Extinction, LOME）并延续至志留纪的放射虫属中，Secuicollacta、Haplotaeniatum与Palaeoephippium在演化过渡阶段保持了稳定的躯体构型，其类群建立更为成功。[原文此处存在内容缺失]本次研究的放射虫样品采自澳大利亚新南威尔士州上奥陶统凯迪阶（Katian）马龙古利组，采样坐标为33°34'57.58"S，148°52'54.06"E。
化石标本由昆士兰大学朱利叶斯·克鲁茨密特矿物研究中心的Zeiss Xradia Versa XRM-500高分辨显微CT扫描仪完成扫描。三维模型通过Avizo® 9.7（2020.2版本）体绘制软件生成。
数据集可通过任意支持读取并运行mpg文件的软件查看。