 However, the supposed other genus of peacock softshells, "Aspideretes", is more closely related to "N. formosa" than had been believed.They differ only in the neural plates between the first pleural scale pair of the bony carapace, which are fused into one in "N. formosa" and unfused in the others.Thus, it has been proposed to unite the two genera under the older name, "Nilssonia".