DOI: 10.15468/bqaaa4
title: A revision of Ophidiaster davidsoni de Loriol and Pellat 1874 from the Tithonian of Boulogne (France) and its transfer from the Valvatacea to the new forcipulatacean genus Psammaster gen. nov.

description: This dataset contains the digitized treatments in Plazi based on the original journal article Fau, Marine, Villier, Loïc, Ewin, Timothy A. M., Gale, Andrew S. (2020): A revision of Ophidiaster davidsoni de Loriol and Pellat 1874 from the Tithonian of Boulogne (France) and its transfer from the Valvatacea to the new forcipulatacean genus Psammaster gen. nov. Fossil Record 23 (2): 141-149, DOI: 10.5194/fr-23-141-2020, URL: http://dx.doi.org/10.5194/fr-23-141-2020Abstract. 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.1 IntroductionAsteroidea (starfish or sea stars) is one of the most diverse echinoderm clades with approximately 1900 extant species (Mah and Blake, 2012) and around 600 extinct species (Villier, 2006) However, the fossil record of Asteroidea is rather scarce (e.g. Gale, 2011; Mah and Blake, 2012). It is generally accepted that all modern sea stars belong to a clade, called Neoasteroidea, which originated during the Triassic (Blake, 1987; Gale, 1987, 2011), with most modern lineages appearing in the Jurassic. Jurassic fossils are therefore essential to understanding the initial diversification and evolutionary history of Asteroidea.Forcipulatacea is one of the major clades within the Neoasteroidea, comprising about 400 extant species (Mah and Blake, 2012) and fewer than 25 extinct species. Forcipulatacea is one of the oldest clades of Neoasteroidea, with the oldest fossils known from the Hettangian (Lower Jurassic) of Switzerland and Germany (Blake, 1990). However, the diversity of forcipulatacean taxa during the Jurassic and their relationships with Triassic groups are still poorly understood. Some fossil taxa, for instance, have been attributed to extant families based on general resemblances (e.g. presence of quadriserial ambulacral pores) rather than synapomorphies (Gale, 2011).Here we re-appraise Ophidiaster davidsoni de Loriol and Pellat, 1874, from the Tithonian of Boulogne, France, demonstrating that this taxon does not belong to the genus Ophidiaster L. Agassiz, 1836 (order Valvatida), as originally assigned by de Loriol and Pellat (1874). Using the phylogenetic characters and matrix from Fau and Villier (2020), we assess the phylogenetic position of Ophidiaster davidsoni within the Forcipulatacea. The combination of original characters justifies the creation of a new genus, Psammaster. The purpose of this study is to reappraise Ophidiaster davidsoni de Loriol and Pellat, 1874 and place it in a phylogenetic context.