Berichte Naturwiss. Verein für Bielefeld und Umgegend 52 (2014), Sven SACHS, Siegfried SCHUBERT, Benjamin P. KEAR with 4 igures Contents Page Summary This note briely introduces a new plesiosaur specimen from the upper Pliensbachian (Lower Jurassic) of Bielefeld-Jöllenbeck (North Rhine-Westphalia, NW Germany). The skeleton compri- ses a partial skull, sections of the vertebral column, ribs and components of the pectoral girdle and limbs. It belonged to an immature individual of 2-3 m length. Important diagnostic features include a prominent notch in the caudal border of the mandibular fossa glenoidalis, craniad cer- vical centra that are higher than long, a pair of foramina subcentralia on the cervicals separated by a broad ventral keel, and a dorsal process on the scapula that bears a gently convex cranial margin, but no pronounced medial thickening. The Bielefeld specimen is one of the most com- plete plesiosaurs currently known from the Pliensbachian and difers from the coeval European taxa Westphaliasaurus and Cryonectes, but shows some similarity to unpublished material from the Pliensbachian of England. The Bielefeld plesiosaur indicates that a substantial diversity of taxa was present in European marine systems during the Pliensbachian stage. Authors: Sven Sachs, Im Hof 9, D-51766 Engelskirchen, E-Mail: Sachs.Pal@gmail.com Siegfried Schubert, Kirschenstraße 24, D-33803 Steinhagen, E-Mail: h-s-s@t-online.de Dr. Benjamin P. Kear, Palaeobiology Programme, Department of Earth Sciences, Uppsala University, Villavägen 16, SE-752 36 Uppsala, E-Mail: benjamin.kear@geo.uu.se Note on a new plesiosaur (Reptilia: Sauropterygia) skeleton from the upper Pliensbachian (Lower Jurassic) of Bielefeld, northwest Germany 1. Introduction 28 2. Discovery and horizon 29 3. Characterisation and comparisons 30 4. Conclusions 33 5. Literature 35 , S. 26 - 35