The bivalved arthropod Tuzoia from the Balang Formation (Cambrian Stage 4) of Guizhou, China, and new observations on comparative species

Tuzoia is a large, bivalved Cambrian arthropod having a widespread distribution in shallow-shelf to deeper marine Lagerstätten; stratigraphically it ranges from Cambrian Series 2 through the Miaolingian Series. In the present study, three species are recognized from relatively deep-water deposits of the Balang Formation (Cambrian Stage 4) of Guizhou, South China: Tuzoia sinensis Pan, 1957, T. bispinosa Yuan et Zhao, 1999 and T. lazizhaiensis sp. nov. The new species is unique in having 6-10 small marginal spines on the dorsal margin, an inflated anterior margin with 3 short, closely spaced marginal spines. These remains, which usually occur as disarticulated valves, are inferred to be parautochthonous. One new specimen of T. lazizhaiensis shows a stalked eye and antenna. New Tuzoia material from the Kaili Biota (Cambrian: Wuliuan Stage) of Guizhou, and from the Guanshan Biota (Cambrian Stage 4) of Yunnan, China, provide additional comparative information about the genus. Some new specim...