Edwards and Bebout, 1981
From dinoflaj3
Edwards, L.E. and Bebout, J.W., 1981: Emendation of Phthanoperidinium Drugg and Loeblich 1967, and a description of P. brooksii sp. nov. from the Eocene of the mid-Atlantic outer continental shelf. Palynology, v.5, p.29-41, pl.1-2.