Data from: The macro- and microfossil record of the middle Cambrian priapulid Ottoia

The stem-group priapulid Ottoia Walcott, 1911, is the most abundant worm in the mid-Cambrian Burgess Shale, but has not been unambiguously demonstrated elsewhere. High-resolution electron and optical microscopy of macroscopic Burgess Shale specimens reveals the detailed anatomy of its robust hooks, spines and pharyngeal teeth, establishing the presence of two species: Ottoia prolifica Walcott, 1911, and Ottoia tricuspida sp. nov. Direct comparison of these sclerotized elements with a suite of shale-hosted mid-to-late Cambrian microfossils extends the range of ottoiid priapulids throughout the middle to upper Cambrian strata of the Western Canada Sedimentary Basin. Ottoiid priapulids represented an important component of Cambrian ecosystems: they occur in a range of lithologies and thrived in shallow water as well as in the deep-water setting of the Burgess Shale. A wider survey of Burgess Shale macrofossils reveals specific characters that diagnose priapulid sclerites more generally, establishing the affinity of a wide range of Small Carbonaceous Fossils and demonstrating the prominent role of priapulids in Cambrian seas.

干群曳鳃动物（stem-group priapulid）奥托虫（Ottoia Walcott, 1911）是中寒武世布尔吉斯页岩（Burgess Shale）中丰度最高的蠕虫类群，但目前尚未在其他地点被明确证实。对布尔吉斯页岩产出的宏观标本开展高分辨率电子与光学显微研究，揭示了其粗壮钩、棘与咽齿的精细解剖结构，据此确立了两个有效物种：丰产奥托虫（Ottoia prolifica Walcott, 1911）与三齿奥托虫新种（Ottoia tricuspida sp. nov.）。通过将这些硬化骨片与一系列赋存于页岩中的中晚寒武世微体化石开展直接对比，本研究将奥托虫类曳鳃动物的分布范围拓展至加拿大西部沉积盆地的中至上寒武统地层中。奥托虫类曳鳃动物是寒武纪生态系统的重要组成部分：该类群广泛出现于多种岩性中，不仅在浅水环境中繁盛，同样在布尔吉斯页岩所代表的深水沉积环境中繁衍兴盛。对布尔吉斯页岩大化石的更广泛调查揭示了可通用诊断曳鳃动物硬化骨片的特定形态特征，由此明确了大量小型碳质化石（Small Carbonaceous Fossils）的亲缘关系，并证实曳鳃动物在寒武纪海洋中发挥了至关重要的生态作用。