Studi Trentini di Scienze Naturali, 99 (2020): 15-19 Studi Trentini di Scienze Naturali vol. 99 Studi Trentini di Scienze Naturali 2020 ISSN 2532-7712 homepage: http://www.muse.it/it/Editoria-Muse/Studi-Trentini-Scienze-Naturali/Pagine/home.aspx © 2020 MUSE - Museo delle Scienze, Trento, Italia Article First record of the genus Polydiadema Lambert, 1888 (Echinoidea) in the Jurassic of Italy Enrico Borghi1* & Alberto Bottazzi2 1 Società Reggiana di Scienze Naturali, Reggio Emilia, Italy 2 Museo Civico “Dal Lago”, Valdagno, Vicenza, Italy Parole chiave Summary • Echinoidea Well preserved regular echinoids, recently collected from the Lower Jurassic Rotzo formation of • Polydiadema Monte Roite (Trento, Northern Italy), are here attributed to Polydiadema depressum (Agassiz in • Giurassico inferiore Agassiz & Desor, 1846). A specimen shows a part of the lantern, which was so far unknown in • Nord-est Italia the genus Polydiadema Lambert, 1888: the lantern is of the Stirodont type, with teeth T-shaped in cross section. Also the spines have not been described yet for the species: they are thin, with crenulate articular surface and the stalk is ornate by fine longitudinal costae. Polydiadema de- Key words pressum lived in a shallow-water muddy environment, associated with bivalves, gastropods and small brachiopods. The geo-stratigraphic distribution of this species, so far known from the • Echinoidea Middle Jurassic (Aalenian-Bathonian) of Western Europe, is extended to the upper Sinemuri- • Polydiadema an-lower Pliensbachian of Italy. • Lower Jurassic • North-eastern Italy Riassunto * Corresponding author: Alcuni echinoidi regolari ben conservati recentemente raccolti nella formazione di Rotzo (gruppo e-mail:
[email protected] dei Calcari Grigi) di Monte Roite (Trento), vengono attribuiti a Polydiadema depressum (Agassiz in Agassiz & Desor, 1846).