Rapid volcanic ash entombment reveals the 3D anatomy of Cambrian trilobites

• 成果类型: Article
• 署名作者: El Albani, Abderrazak; Mazurier, Arnaud; Edgecombe, Gregory D.; Azizi, Abdelfattah; El Bakhouch, Asmaa; Berks, Harry O.; Bouougri, El Hafid; Chraiki, Ibtissam; Donoghue, Philip C. J.; Fontaine, Claude; Gaines, Robert R.; Ghnahalla, Mohamed; Meunier, Alain; Trentesaux, Alain; Paterson, John R.
• 署名单位: Universite de Poitiers; Natural History Museum London; Cadi Ayyad University of Marrakech; University of Bristol; Cadi Ayyad University of Marrakech; Claremont Colleges; Pomona College; Universite du Littoral-Cote-d'Opale; Universite de Lille; University of New England
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-12029
• DOI: 10.1126/science.adl4540
• 发表日期: 2024-06-28
• 页码: 1429-1435
• 关键词: mass mortality; high-atlas; EVOLUTION; preservation; ordovician; morocco; paleoecology; concretions; triarthrus; appendages

摘要

Knowledge of Cambrian animal anatomy is limited by preservational processes that result in compaction, size bias, and incompleteness. We documented pristine three-dimensional (3D) anatomy of trilobites fossilized through rapid ash burial from a pyroclastic flow entering a shallow marine environment. Cambrian ellipsocephaloid trilobites from Morocco are articulated and undistorted, revealing exquisite details of the appendages and digestive system. Previously unknown anatomy includes a soft-tissue labrum attached to the hypostome, a slit-like mouth, and distinctive cephalic feeding appendages. Our findings resolve controversy over whether the trilobite hypostome is the labrum or incorporates it and establish crown-group euarthropod homologies in trilobites. This occurrence of moldic fossils with 3D soft parts highlights volcanic ash deposits in marine settings as an underexplored source for exceptionally preserved organisms.