Abstract
Abstract. Forcipulatacea is one of the three major groups of extant
sea stars (Asteroidea: Echinodermata), composed of 400 extant species, but
only known from fewer than 25 fossil species. Despite unequivocal members
being recognized in the early Jurassic, the evolutionary history of this
group is still the subject of debate. Thus, the identification of any new
fossil representatives is significant. We here reappraise Ophidiaster davidsoni de Loriol and
Pellat 1874 from the Tithonian of Boulogne, France, which was assigned to
another major extant group, the Valvatacea, and reassign it within a new
forcipulatacean genus, Psammaster gen. nov. Psammaster davidsoni gen. nov. possess key Forcipulatacea
synapomorphies including compressed ambulacrals and adambulacrals and
typical organization of the body wall and arm ossicles. A phylogenetic
analysis including Psammaster davidsoni gen. nov. does not place it within any existing
forcipulatacean family. Instead, Psammaster davidsoni gen. nov. exhibits a mix of plesiomorphic
and derived characters and is resolved as a sister clade to a large group
including the Asteriidae, Stichasteridae, and Heliasteridae. Removal of this
species from the Ophidiasteridae means their oldest fossil representative
now dates from the Santonian, Upper Cretaceous.