File:Cambrian bivalved euarthropods.webp

English: Morphological reconstructions of selected Cambrian bivalved stem-group euarthropods. Telson and tail flukes highlighted (grey) for comparison. Members of Clypecarididae (A,B) are distinguished by non-overlapping and acuminate tail flukes that bear straight setae on their inner margin. By contrast, Waptiidae (D–H) have dorsoventrally flattened tail flukes that overlap each other in various degrees, some with multiple articulations (F–H). (A) Clypecaris serrata, Stage 3 Xiaoshiba, China (this study). (B) C. pteroidea, Stage 3 Chengjiang, China; reconstruction includes dorsal spines as implied by the presence of paired sockets on the trunk tergites. (C) Erjiecaris minusculo, Stage 3 Chengjiang, China. (D) Synophalos xynos, Stage 3 Chengjiang, China. (E) Plenocaris plena, Stage 5 Burgess Shale, Canada. (F) Chuandianella ovata, Stage 3 Chengjiang, China; (G) Pauloterminus spinodorsalis, Stage 3 Sirius Passet, Greenland; (H) Waptia fieldensis, Stage 5 Burgess Shale, Canada. Scale bars: 5 mm.