The appendicular morphology of Sinoburius lunaris and the evolution of the artiopodan clade Xandarellida (Euarthropoda, early Cambrian) from South China

A groundbreaking study reveals the detailed appendicular morphology of Sinoburius lunaris, a rare and enigmatic early Cambrian euarthropod from the UNESCO-listed Chengjiang Fossil Site. Using X-ray computed tomography, researchers uncovered unprecedented 3D preservation of its ventral anatomy, including biramous limbs with unique features such as reduced antennae and specialized exopods. The findings challenge prior assumptions about arthropod evolution, supporting the monophyly of the Xandarellida clade and proposing a transformation series for key morphological traits like eye slits. This work not only advances our understanding of Sinoburius but also highlights the potential of tomographic techniques to unravel the complexity of Palaeozoic euarthropods.

Chen, X., Ortega-Hernández, J., Wolfe, J. M., Zhai, D., Hou, X., Chen, A., Mai, H., & Liu, Y. (2019). The appendicular morphology of Sinoburius lunaris and the evolution of the artiopodan clade Xandarellida (Euarthropoda, early Cambrian) from South China. BMC Evolutionary Biology, 19(1). https://doi.org/10.1186/s12862-019-1491-3