The Weeks Formation preserves a diverse, yet largely undescribed, exceptionally preserved fauna of late Guzhangian age. Here I describe Notchia weugi gen. et sp. nov., a new arthropod characterized by a short cephalon, a trunk with 12 tergites and weakly differentiated into two morphological regions, and a spine-bearing rectangular telson. This combination of characters is incompatible with its assignment to any known groups. The new taxon also adds to examples of convergent evolution of ramified digestive glands in arthropods, possibly as an adaptation to infrequent feeding.