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.