ABSTRACT A new rare Upper Ordovician mound dwelling palaeoloricate chiton is described as Crassaplax collicola gen. et sp. nov. from three large isolated intermediate valves from the Katian carbonate mud mounds of the Boda Limestone in the Siljan district of central Sweden. Together with the previously known Spicuchelodes? sp., also from the Boda Limestone, these are the only known Late Ordovician mound dwellers so far among the palaeoloricates, adding to Ordovician environments with reported chiton remains. Crassaplax collicola is distinguished from other Ordovician palaeoloricate chitons by their thick and large valves that can be 2 cm in length, and especially the clear differentiation between the lateral and central valve areas.

中文翻译：

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来自瑞典中部晚奥陶世博达石灰岩的新大型土墩栖居石鳖（软体动物）

摘要 一种新的稀有的上奥陶统土丘栖居的古古石鳖被描述为 Crassaplax collicola gen。等 sp. 十一月 来自瑞典中部 Siljan 地区 Boda Limestone 的 Katian 碳酸盐泥丘的三个大型隔离中间阀。与之前已知的 Spicuchelodes 一起？sp.，也来自博达石灰岩，这些是迄今为止古陆系中唯一已知的晚奥陶世土墩居民，增加了奥陶纪环境，据报道有石斑藻遗骸。Crassaplax collicola 与其他奥陶纪古陆龟的区别在于它们厚而大的瓣膜，长度可达 2 厘米，尤其是侧瓣区和中央瓣膜区之间的明显区别。