Two New Cassis (Gastropoda: Cassidae) and a New Malea (Gastropoda: Tonnidae) from the Pliocene and Pleistocene Beds of Southern Florida

Abstract

Two new fossil Helmet Shells of the genus Cassis Scopoli, 1777 (Cassidae) and a new fossil Grinning Tun Shell of the genus Malea Valenciennes, 1832 (Tonnidae) are described from the Pliocene and Pleistocene fossil beds of southern Florida. The new Helmet Shells, Cassis rasae n. sp. and Cassis viliusi n. sp., were both collected in the rich fossil beds of the Holey Land Member of the Bermont Formation (Calabrian Stage, Early Pleistocene) and the new Grinning Tun, Malea hyaducki n. sp., was collected in the Fruitville Member (Kissimmee River Valley equivalent beds) of the Tamiami Formation (late Piacenzian Stage of the Pliocene). The discovery of two new large Helmet Shells in the Holey Land Member demonstrates that four species of Cassis are present in the Bermont Formation, making this the single largest fossil Cassis fauna found anywhere on Earth. The new Grinning Tun represents the oldest-known Malea found in Florida, and is the direct ancestor of the Gelasian Pleistocene Malea springi (Caloosahatchee Formation) and the Calabrian Pleistocene Malea petiti (Bermont Formation).