Tuberculate fragments referred to Nikolarites spasskyi are compared with a complete carapace and other material of Spinospitella from Cambrian Series 2, Stage 4 in North Greenland. The descriptions expand earlier brief records from Laurentia of the two bradoriids, originally described from Siberia and Australia, respectively. The mutually exclusive occurrences of the two taxa indicate ecological control of their distribution in North Greenland. Robust fragments of Nikolarites spasskyi occur in reworked higher energy deposits of the Aftenstjernesø Formation, while thin-walled carapaces of Spinospitella characterise deeper water mudstones within the Buen and Aftenstjernesø formations.

将被称为Nikolarites spasskyi 的结核碎片与来自北格陵兰岛寒武纪系列 2 第 4 阶段的完整的甲壳和Spinospitella 的其他材料进行了比较。这些描述扩展了最初分别来自西伯利亚和澳大利亚的两种布拉多龙类的 Laurentia 的早期简要记录。这两个类群的相互排斥的出现表明它们在北格陵兰的分布受到生态控制。Nikolarites spasskyi 的坚固碎片出现在 Aftenstjernesø 地层改造后的高能矿床中，而 Spinospitella 的薄壁甲壳是Buen 和 Aftenstjernesø 地层内较深水泥岩的特征。