Data from: Paleocommunity analysis of the Burgess Shale Tulip Beds, Mount Stephen, British Columbia: comparison with the Walcott Quarry and implications for community variation in the Burgess Shale

The Tulip Beds locality on Mount Stephen (Yoho National Park, British Columbia) yields one of the most abundant and diverse (~10,000 specimens in 110 taxa) Burgess Shale fossil assemblages in the Canadian Rockies. Detailed semi quantitative and quantitative analyses of this assemblage suggest strong similarities with the Walcott Quarry on Fossil Ridge. Both assemblages are dominated by epibenthic, sessile, and suspension feeding taxa, mostly represented by arthropods and sponges and have comparable diversity patterns, despite sharing only about half the genera. However, the Tulip Beds has a higher relative abundance of suspension feeders and taxa of unknown affinity compared to the Walcott Quarry. These biotic variations are probably largely attributable to ecological and evolutionary differences between the two temporally distinct communities that adapted to similar, but not identical, environmental settings. For instance, the Tulip Beds is farther away from the Cathedral Escarpment than the Walcott Quarry. The Tulip Beds and Walcott Quarry assemblages are more similar to each other than either one is to the assemblages of the Chengjiang biota, although the relative diversity of major taxonomic groups and ecological patterns are similar in all assemblages. The conserved diversity patterns and ecological structures among sites suggest that the ecological composition of Cambrian Burgess Shale-type communities was relatively stable across wide geographic and temporal scales.

不列颠哥伦比亚省幽鹤国家公园斯蒂芬山上的郁金香床化石点，产出了加拿大落基山脉中丰度与多样性均位居前列的布尔吉斯页岩（Burgess Shale）化石组合之一，共计包含约10000件标本，隶属于110个分类群（taxa）。针对该化石组合开展的详细半定量与定量分析表明，其与化石岭（Fossil Ridge）的沃尔科特采石场（Walcott Quarry）化石组合存在高度相似性。尽管二者仅共享约半数的属（genera），但两类化石组合均以底表栖息（epibenthic）、固着生活（sessile）的滤食性（suspension feeding）分类群为优势类群，且多样性模式相近，这些优势类群主要由节肢动物与海绵动物构成。不过相较于沃尔科特采石场，郁金香床化石点的滤食性类群与亲缘关系不明的分类群相对丰度更高。这类生物类群差异大概率主要源于两个时代不同的群落之间的生态与演化差异——二者均适应了相似但并非完全一致的环境背景。例如，郁金香床化石点相较于沃尔科特采石场，距离大教堂断崖（Cathedral Escarpment）更远。尽管所有三类化石组合的主要分类群相对多样性与生态模式均较为相似，但郁金香床与沃尔科特采石场的化石组合彼此间的相似度，要高于二者任意一方与澄江生物群（Chengjiang biota）化石组合的相似度。不同采样点间保守一致的多样性模式与生态结构表明，寒武纪（Cambrian）布尔吉斯页岩型群落的生态组成在大范围的地理与时间尺度上均相对稳定。