Are hyoliths Palaeozoic Iophophorates?

• 来源期刊: 国家科学评论（英文版）
• 关键词: orthothecid the Chengjiang Lagerst(a)tte Cambrian soft parts lophophore
• 年，卷（期）: 2020,（2）
• 页码范围: 453-469
• 页数: 17页
• 语种: 英文
• DOI: 10.1093/nsr/nwz161

摘要

The phylogenetic position ofhyoliths has long been unsettled,with recent discoveries of a tentaculate feeding apparatus (‘lophophore’) and fleshy apical extensions from the shell (‘pedicle’) suggesting a lophophorate affinity.Here,we describe the first soft parts associated with the feeding apparatus of an orthothecid hyolith,Triplicatella opimus from the Chengjiang biota of South China.The tuft-like arrangement of the tentacles of T.opimus differs from that ofhyolithids,suggesting they collected food directly from the substrate.A reassessment of the feeding organ in hyolithids indicates that it does not represent a lophophore and our analysis of the apical structures associated with some orthothecids show that these represent crushed portions of the shell and are not comparable to the brachiopod pedicle.The new information suggests that hyoliths are more likely to be basal members of the lophotrochozoans rather than lophophorates closely linked with the Phylum Brachiopoda.