Rarest within the genus is the Middle Ordovician species Gravicalymene magnotuberculata, which is also amongst the rarest of all Calymenidae and regionally confined to two exposures in New York State.
The most infrequent species within its genus is Gravicalymene magnotuberculata from the Middle Ordovician period, a rarity that extends to the entire Calymenidae family, with only two known locations in New York State.