First evidence of a large predatory plesiosaurian from the Lower Cretaceous non-marine ‘Wealden facies’ deposits of northwestern Germany

Sachs, S., Hornung, J.J., Lallensack, J.N. &amp; Kear, B.P., November.2017. First evidence of a large predatory plesiosaurian from the Lower Cretaceous non-marine ‘Wealden facies’ deposits of northwestern Germany. <i>Alcheringa 42</i>, 501-508. ISSN 0311-5518. Here, we describe the incomplete mandible of a large-skulled ‘pliosauromorph’ plesiosaurian from the Lower Cretaceous (Berriasian) of northwestern Germany. The fossil derives from limnic–brackish ‘Wealden facies’ deposits of the Deister Formation (Bückeberg Group), and is preserved as a natural mould in fine-grained sandstone. Examination of the original remains, in conjunction with a three-dimensional photogrammetrically digitized ‘cast’, revealed a conspicuous rosette of symphyseal alveoli, which would otherwise typically characterize Early–Middle Jurassic macrophagous plesiosaurians including rhomaleosaurids and the pliosaurid <i>Simolestes</i>. The Deister Formation ‘pliosauromorph’ represents the first record of a large-bodied plesiosaurian macrocarnivore from the ‘Wealden-facies’ strata of Europe, and thus adds a previously unrecognized trophic level of aquatic apex predators to the Early Cretaceous non-marine ecosystems of Europe. <i>Sven Sachs* [</i>[e-mail]<i>] Naturkunde-Museum Bielefeld, Abteilung Geowissenschaften, Adenauerplatz 2, 33602 Bielefeld, Germany and Im Hof 9, 51766 Engelskirchen, Germany; Jahn J. Hornung [</i>[e-mail]<i>] Niedersächsisches Landesmuseum Hannover, Willy-Brandt-Allee 5, 30169 Hannover, Germany; Jens N. Lallensack [</i>[e-mail]<i>] Steinmann-Institut für Geologie, Mineralogie und Paläontologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 8, 53115 Bonn, Germany; Benjamin P. Kear [</i>[e-mail]<i>] Museum of Evolution, Uppsala University, Norbyvägen 16, Uppsala SE-752 36, Sweden.</i>