The width of the shell is 4.84–44.83 mm. Valeues of δ13C were −26.42‰ ± 0.67. A distinguishingfactor of the Gigantopelta aegis is their large size, hence the name, which translates to "gigantic shield" in Latin. While other peltospirids reach shell diametersizes of 15mm on average, the Gigantopelta aegis can grow up to 45.7 mm. The shell is also thickly coated with a layer of sulphide. However, this is typical of other vent-dwelling gastropods. Another distinguishing factor for the Gigantopelta species is that sexual dimorphism is not exhibited, as seen in other peltopsirids.