贵州剑河寒武系凯里组脊状单臂螺(Haplophrentis carinatus)埋藏特征及与始海百合共生关系探讨

贵州剑河寒武系凯里组软舌螺化石丰富、埋藏形式多样,其中以脊状单臂螺Haplophrentis carinatus化石数量最多、保存最为完整。过去有关学者对凯里组单臂螺化石的研究主要集中在化石分类学方面,对脊状单臂螺埋藏特征及与其他生物共生关系缺乏深入探讨。本文对324块脊状单臂螺化石标本进行系统研究对比后发现,凯里组脊状单臂螺口盖化石埋藏形式有四类:口盖单独保存、口盖以内模或外模化石形式保存、口盖与锥壳完全绞合保存、口盖与锥壳不完全绞合保存;附肢保存较少;锥壳多以内模化石形式保存;脊状单臂螺内模化石与印痕化石上普遍出现类似软体保存形成的三分叉结构,这类三分叉结构属于后期埋藏因素造成的次生结构。文中还对脊状单臂螺与始海百合共生关系进行探讨,并将二者共生关系归为偏害共生。

Taphonomic features of Haplophrentis carinatus from the Cambrian Kaili Formation, Jianhe, Guizhou and its symbiotic relationship with the eocrinoids

The Cambrian Kaili Formation in Jianhe, Guizhou Province yields abundant hyolith fossils, among which Haplophrentis carinatus accounts for the largest proportion and is the most well-preserved. Previous research on Hap-lophrentis carinatus is merely limited to taxonomy, lacking further discussion on its taphonomic features and its symbiotic relationship with other organisms. Herein, we conducted systematic research on 324 specimens of Haplophrentis carinatus. Four taphonomic modes of opercula are recognized: separately preserved opercula, internal or external molds of opercula, partially and completely articulated opercula. Few helens are preserved and conchs are mainly preserved as internal molds. In addition, a trident-like structure, occurring on internal molds or impressions and resembling soft-tissue preservation, is a taphonomic artifact. The symbiotic relationship between Haplophrentis carinatus and eocrinoids is also discussed and this relationship is treated as an amensalism.