Bicknell Russell D C, Klompmaker Adiël A, Edgecombe Gregory D, McCoy Victoria E, Young Andrew, Lauer Bruce, Lauer René, Cuomo Carmela
Division of Paleontology, American Museum of Natural History, New York City, New York 10027, USA.
Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia.
Biol Lett. 2025 Mar;21(3):20240734. doi: 10.1098/rsbl.2024.0734. Epub 2025 Mar 19.
Gregarious behaviours in modern and fossil arthropods are commonly associated with defensive strategies, mass moulting and synchronous reproduction. Such behaviour is scarcely documented in the crustacean fossil record. Identifying clusters in extinct Pancrustacea is, therefore, important for understanding the evolutionary history and origin of crustacean gregariousness. Cyclida, an order of extinct, enigmatic pancrustaceans that have been subject to limited palaeoecological examination, represents an ideal group for testing the presence of gregarious behaviour. Here, we report a cluster of 50 individuals from the Serpukhovian-aged Bear Gulch Limestone of Montana, USA, expanding the exceptionally rare record of cyclidan aggregations. The presence of articulated specimens with appendages and possible gill preservation supports the interpretation of carcasses that were preserved during a rapid burial event. We propose that this cluster records either a mass moulting event or clustering for shelter, representing one of the oldest records of crustacean gregariousness. These findings provide important insights into cyclidan life modes and ecological interactions in Carboniferous marine environments.
现代和化石节肢动物的群居行为通常与防御策略、大规模蜕皮和同步繁殖有关。这种行为在甲壳类动物化石记录中鲜有记载。因此，识别已灭绝泛甲壳动物中的集群对于理解甲壳类动物群居行为的进化历史和起源至关重要。环虾目是一类已灭绝的神秘泛甲壳动物，对其古生态学研究有限，是测试群居行为是否存在的理想类群。在这里，我们报告了来自美国蒙大拿州谢尔普霍夫阶熊谷石灰岩的50个个体的集群，扩展了极为罕见的环虾目聚集记录。带有附肢且可能保留鳃的关节连接标本的存在，支持了这些尸体是在快速掩埋事件中被保存下来的解释。我们认为这个集群记录了一次大规模蜕皮事件或为寻求庇护而聚集的行为，代表了甲壳类动物群居行为最古老的记录之一。这些发现为石炭纪海洋环境中环虾目的生活方式和生态相互作用提供了重要见解。
