 Based on this material, which consisted of a 40 cm long arm and 115 cm tentacle, Kir Nesis estimated the mantle length at 265–275 cm, and the total length at over 4 m. This would make it the second largest squid species in terms of mantle length, after only the colossal squid, and even larger than the giant squid.However, Nesis added that "because of its narrow body, we conclude that its mass is consistently lower than that of the other large squids".The type specimen of "G. phyllura" was collected in Monterey Bay, California and is deposited in the National Museum of Natural History.