Yanmaguirus is a large, dragonfly-like Neopteron that sports a sleek, shiny, reflective purple exoskeleton with yellow spikes across its body. The ventral side of the creature is orange. Yanmaguirus has six legs, the foremost pair end in giant crab-like pincers. The abdomen is long and slender and consists of 10 segments, the last segment ending in a pair of claspers and a stinger. The eyes are a bright red and the toothed mandibles resemble a reptilian mouth of sorts.