The present study elaborates the morphological features and ultrastructures of maikhanellid shells and, on this basis, deals with their classification, phylogeny and evolutionary trend, with a rich and well preserved collection from the Early Cambrian Meishucunian Stage in eastern Yunnan of China.

Described in the present paper are monoplacophorans from the Earliest Cambrian Meishucunian Stage in northeastern Yunnan, including 5 new genera, 7 new species and 1 undetermined species, namely Striatoconus yuluensis gen.

The Meishucun section is considered as one of the best candidate for the international strato-type of the Precambrian-Cambrian boundary.

According to the newly found Meishucun fauna member: Mcrocornus (? ), Cofeoloides and Rugatotheca,combined with the facts that Qinghezhen fauna found in this area is equivalent to first to third fossil groups of Meishun cun stage, it is concluded that the siliceous marble should be classified into the early stage of Lower Cambrian.

Besides the original fossils, the new members of Meishucun fauna are Microcwnus (?), Coleoloides, Rugatotheca, a new genus Honghuagouchites and a sponge -like Chifengospongia, which enrich the members of the fauna and provide some new evidence for the comparison of known fossils at the early stage of early Cambrian.