Zhenghecaris shankouensis gen. et sp. nov. is one of the largest 'bivalved' arthropods of the Lower Cambrian Maotianshan Shale fauna. Its non-mineralized carapace was dome-like, laterally compressed, armed with rostral features, and probably enclosed the entire body of the animal. Zhenghecaris was provided with elliptical stalked lateral eyes. The carapace design, external ornament and visual organs of Zhenghecaris suggest affinities with the Thylacocephala, an extinct (Lower Silurian to Upper Cretaceous) group of enigmatic arthropods whose origins remain poorly understood. The bivalved arthropods Isoxys and Tuzoia (Lower and Middle Cambrian) are two other potential thylacocephalan candidates making this group of arthropods a possible new component of Cambrian marine communities. Zhenghecaris, Isoxys, and Tuzoia are interpreted as nektonic animals that probably inhabited the lower level of the water column in shallow shelf settings at depths of perhaps 100-150 m or less. Their feeding mode either in the water column (e.g., mesozooplankton) or on the substrate (e.g., small epibenthos, detritus) is uncertain, although some of these arthropods were possibly mid-water predators (e.g., Isoxys with raptorial appendages).

Key words: Arthropoda, Zhenghecaris, Lagerstätte, Cambrian, Maotianshan Shale, China.

Jean Vannier [ jean.vannier@univ-lyon1.fr ] and Sylvain Charbonnier, UMR 5125 'Paléoenvironnements et Paléobiosphčre', Université Claude Bernard Lyon 1, Campus Universitaire de la Doua, 2, rue Raphaël Dubois, 69622 Villeurbanne, France; Jun-Yuan Chen and Di-Ying Huang, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science, 39 East Beijing Road, Nanjing 210008, China; Xiu-Qiang Wang, Biological Sciences Department, Nanjing University. Nanjing 210093, China.