Phylogeny and evolutionary significance of vermiform animals from the Early Cambrian Chengjiang Lagerstatte

The Early Cambrian Chengjiang Biota of China has preserved many species of vermiform animals in exquisite detail, which provide a unique window into the origin and early evolution of different vermiform phyla. This article reviews and discusses the forty-five Chengjiang vermiform animals discovered so far, and specifically comments on the phylogeny, modes of life, evolutionary significance as well as existing debates concerning the Chengjiang priapulid and lobopodian phyla. This article analyzes existing problems with Chengjiang vermiform morphological research and highlights various factors that affect the final preserved fossil morphology, including taphonomy and shape change caused by vermiform movement, as well as proposing that Anningvermis multispinosa and Corynetis brevis are synonymous. Chengjiang vermiform animals displayed a great diversity of morphologies and ecological roles, which is significant for understanding the origin and evolution of early metazoans; the potential for future research is enormous but needs to be broadened by interdisciplinary work involving taphonomy, geochemistry, cladistics, and genetics.