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Halwaxiids是一类体表覆有骨质鳞片的寒武纪后生动物,它包含了在早期后生动物进化中占据关键位置的两个化石动物类群Halkieriids和Wiwaxids。但自1995年以来包含Halkieria和Wiwaxia在内的Halwaxiids进化枝在不断被修正,而近年来,随着新化石和新证据的出现,围绕Halkieria和Wiwaxia的分类归属展开了更激烈的争论。争论焦点集中在以下问题:Halkieria和Wiwaxia的亲缘关系到底如何?Halkieria究竟属于冠轮动物的基群,还是可直接归为软体动物或环节动物?Wiwaxia是软体动物还是环节动物的基群?这些问题的解决将为确定Halwaxiids的系统分类地位提供重要依据,将使描述环节动物与软体动物在分化初期的身体构造趋势成为可能,也将为软体动物、环节动物和腕足动物的起源与分化关系提供重要线索和基本资料。
Halwaxiids are a group of Cambrian epigenetic surface covered with bone scales that contains Halkieriids and Wiwaxids, two fossil fauna that dominate the evolution of early metazoan. However, the clades of Halwaxiids, including Halkieria and Wiwaxia, have been constantly revised since 1995, and in recent years there has been a much heated debate over the categorization of Halkieria and Wiwaxia with the advent of new fossils and new evidence. The focus of the debate is on the following questions: What is the relationship between Halkieria and Wiwaxia? Is Halkieria a group of Crown-wheel animals or directly classified as molluscs or annelids? Is Wiwaxia a mollusk or a herd of annelids? Will provide an important basis for determining the systematic taxonomic status of Halwaxiids. This will make it possible to describe the body structure trend of the synapse animals and molluscs at the early stage of differentiation and will also provide important information on the origin and differentiation of mollusks, synaptic and brachiopods Clues and basic information.