A new species of Hallucigenia from the Cambrian Stage 4 Wulongqing Formation of Yunnan (South China) and the structure of sclerites in lobopodians

摘要

Hallucigenia hongmeia sp. nov. and Hallucigenia sparsa are described from the Cambrian Stage 4 Guanshan fossil Lagerst?tte of Wulongqing Formation from Guangwei in Kunming district, Yunnan Province, South China. The paired trunk sclerites of lobopodians reveal a general net-like microstructure, which is documented for the genera Hallucigenia, Onychodictyon and Microdictyon . This microstructure is comparable to a similar microstructure in paired trunk sclerites of the palaeoscolecidan sensu lato Cricocosmia and Tabelliscolex . The net-like trunk sclerites of lobopodians are interpreted as having carried numerous sensory or secretory papillae. Lobopodian sclerites such as Hallucigenia , Onychodictyon and Microdictyon and the palaeoscolecidans s.l. Cricocosmia and Tabellicsolex were primarily composed of tanned organic structures. Duplicates of trunk sclerites in Microdictyon and Cricocosmia point to a moulting of the external cuticle. The structure and form of prominent claws in Hallucigenia hongmeia sp. nov. are interpreted as indicative of an adapted lifestyle in the epibenthos.