Earliest siphuncle-bearing cephalopod from the early Cambrian

Recent cephalopods are the most intelligent invertebrates and are unique among molluscs in ancestrally possessing chambered, gas-filled shells penetrated lengthwise by a siphuncle that regulates buoyancy that, combined with jet propulsion, enables a nektonic and mostly predatory lifestyle through jet propulsion. The origin of this key innovation remains enigmatic, as major gaps exist between the earliest accepted cephalopod, Plectronoceras cambria from the late Cambrian, and molecular clock estimates placing the lineage’s divergence from other molluscs in the early Cambrian. Here we report Eosceras shaanxiense gen. et sp. nov., a millimetre-sized cephalopod with an orthoconic shell from the Shuijingtuo Formation (Cambrian Stage 3) of South China. Internally, the shell exhibits multiple septa and a peripherally situated segmented tube that appears to bridge the septa through minute canals, indicating that the soft body migrated anteriorly to form successive chambers during growth wh..., , # Earliest siphuncle-bearing cephalopod from the early Cambrian Dataset DOI: [10.5061/dryad.qbzkh18zk](https://doi.org/10.5061/dryad.qbzkh18zk) ## Description of the data and file structure Micro-CT scanning data was performed on specimens CUBar297 (GQ-LYB-4)-1(**20231122_gjf_Bar297-1_3.72um-tiff.zip**), CU(CT-eosceras)-7(**20260106_gjf_eosceras-7_2.72um_tiff.zip**) and CU(CT-eosceras)-11(**20260107_gjf_eosceras-11_2.04um_tiff.zip**) with the Zeiss Xradia 520 system at the State Key Laboratory of Continental Dynamics of Northwest University in Xi’an, Shaanxi Province, China. Scanning conditions were 40 kV accelerating voltage, 80 μA beam current, and an isotropic voxel size of 3.72 μm, 2.72 μm and 2.04 μm, respectively. Approximately 1,000 projection images were acquired in TIFF format. Data were reconstructed using standard, filtered back-projection algorithms and visualized in VG Studio Max 2.2 for three-dimensional volume rendering and segmentation. ## Code/software VG Studio M..., , , **Changes after Mar 10, 2026:** We changed the files name.现生头足类（cephalopods）是最为聪慧的无脊椎动物，在软体动物中独具一格：其祖先拥有由体管（siphuncle）纵向贯穿的分室充气外壳，体管可调节浮力，结合喷气推进机制，使其能够营自游（nektonic）且以捕食为主的生活方式。这一关键创新的起源至今仍成谜，因为目前公认的最早头足类——晚寒武世的坎布里亚盘角石（Plectronoceras cambria）——与分子钟估算的该类群于早寒武世便与其他软体动物分化的时间节点之间，存在巨大的演化时间空白。本研究报道了产自中国华南寒武统第3阶水晶沱组（Shuijingtuo Formation）的毫米级直壳头足类新属新种：陕西始角石（Eosceras shaanxiense gen. et sp. nov.）。该壳体内部具有多层隔壁，以及一处位于周缘的分节管道，该管道似乎通过微细管道连接各隔壁，表明生长过程中软体组织向前迁移以形成后续的壳体室…… # 早寒武世已知最早具体管的头足类 数据集DOI：[10.5061/dryad.qbzkh18zk](https://doi.org/10.5061/dryad.qbzkh18zk) ## 数据与文件结构说明 本研究使用蔡司Xradia 520型显微CT系统，在中国陕西省西安市西北大学大陆动力学国家重点实验室，对三件标本开展了显微CT扫描：CUBar297 (GQ-LYB-4)-1（**20231122_gjf_Bar297-1_3.72um-tiff.zip**）、CU(CT-eosceras)-7（**20260106_gjf_eosceras-7_2.72um_tiff.zip**）以及CU(CT-eosceras)-11（**20260107_gjf_eosceras-11_2.04um_tiff.zip**）。 扫描参数如下：加速电压40kV，束流80μA，三件扫描的各向同性体素尺寸分别为3.72μm、2.72μm与2.04μm。共采集约1000张TIFF格式的投影图像。数据采用标准滤波反投影算法进行重建，并使用VG Studio Max 2.2完成三维体绘制与分割可视化。 ## 代码与软件 VG Studio M…… **2026年3月10日后的修改说明：** 我们已变更相关文件名。