Data from: Diachronous increase in early Cambrian ichnofossil size and benthic faunal activity in different climatic regions

In order to clarify the pattern of diversification and processes of biological activity during the Cambrian radiation, ichnofossils were comparatively studied in the early Cambrian sections of Newfoundland, South China and western Mongolia. Special attention was paid to size distributions of the most common ichnogenus, Planolites, and the densities of all the observed ichnofossils that preserve animal activity as expressed by bedding plane bioturbation indices (BPBI). From the Fortune Head section in Newfoundland, a clear size increase in the ichnogenus Planolites is confirmed from the Treptichnus pedum Zone to the overlying Rusophycus avalonensis Zone. The BPBI also shows much stronger biological activity in the R. avalonensis Zone than in the T. pedum Zone. In Meishucun, South China and Gobi-Altai, Mongolia, however, a variety of Planolites sizes had already appeared in the T. pedum Zone, and the BPBI's on some bedding surfaces of the T. pedum Zone are already comparable to those in the R. avalonensis Zone in Newfoundland. In the earliest Cambrian, diversification and increase in the biological activity of the benthic fauna were diachronous in the wide geographic scale, starting earlier at lower latitudes (South China and western Mongolia) than at higher latitudes (Newfoundland), reflecting differences in the onset of Cambrian benthic animal activity under different climatic conditions.

为阐明寒武纪大爆发期间生物多样性演化模式与生物活动过程，研究团队对纽芬兰、华南及蒙古西部的寒武纪早期地层剖面中的遗迹化石（ichnofossils）开展了对比研究。研究重点聚焦于最常见遗迹属（ichnogenus）漫游迹（Planolites）的尺寸分布，以及以层面生物扰动指数（bedding plane bioturbation indices, BPBI）表征的所有记录动物活动的遗迹化石的密度。在纽芬兰福琼角剖面中，从特雷普提奇努斯带（Treptichnus pedum Zone）至其上覆的阿瓦隆皱叶迹带（Rusophycus avalonensis Zone），漫游迹的尺寸呈现出明确的递增趋势；层面生物扰动指数（BPBI）同样显示，阿瓦隆皱叶迹带的生物活动强度远高于特雷普提奇努斯带。然而在华南梅树村与蒙古戈壁-阿尔泰地区，特雷普提奇努斯带中就已出现多种尺寸的漫游迹，且该带部分层面的生物扰动指数已可与纽芬兰阿瓦隆皱叶迹带的水平相当。寒武纪最早期，底栖动物群的生物多样性与生物活动强度在广阔地理尺度上呈现穿时性特征：低纬度区域（华南与蒙古西部）的寒武纪底栖动物活动起始时间早于高纬度区域（纽芬兰），这反映了不同气候条件下寒武纪底栖动物活动启动时机的差异。