|mhorn||Дата: Sunday, 28.10.2012, 12:11 | Сообщение # 1|
|Knutsen, E.M., Druckenmiller, P.S. & Hurum, J.H. (2012) A new plesiosauroid (Reptilia: Sauropterygia) from the Agardhfjellet Formation (Middle Volgian ) of central Spitsbergen, Norway // Norwegian Journal of Geology, Vol. 92, P.213-234. |
At present, our knowledge of plesiosauroid diversity from the uppermost Jurassic (Tithonian/Volgian) is very limited. Newly discovered mate-rial from the Slottsmøya Member of the Agardhfjellet Formation of central Spitsbergen, Svalbard, contributes significant new information on this poorly known interval and helps bridge a temporal gap between better known plesiosaurians from the older Jurassic deposits of Europe, and Cre-taceous of North America. The partially articulated skeleton of a juvenile long-necked plesiosaurian, PMO 216.839, is one of the most complete plesiosaur fossils known from Spitsbergen and represents a new taxon, Djupedalia engerigen. et sp. nov. Whilst sharing some similarities with previ-ously described taxa from the Oxford Clay (Muraenosaurus, Tricleidus, and Cryptoclidus) and the Kimmeridge Clay formations (Kimmerosaurus) of England, the new taxon can be diagnosed by features of the cervical vertebrae, including centrum proportions and morphology, a very pronounced posterior shift in the neural spines relative to the centrum, fused prezygapophyses and greatly elongated postzygapophyses, as well as extremely short dorsal neural spines and femora that are longer than the humeri. The new taxon can also be distinguished from other newly-described plesiosauroids from Svalbard, thus indicating that several plesiosaurian taxa existed at high paleolatitudes during the Late Jurassic.
Middle Jurassic - Lower Cretaceous ammonites & aptychi