A description and phylogenetic relationship of a polycotylid plesiosaur (Reptilia: Sauropterygia) from the Upper Cretaceous (Turonian) of Goulmima, Morocco Master thesis by Patrick Ronander 2007 Contents Contents .................................................................................................................................................................... 2 Abstract ..................................................................................................................................................................... 4 Introduction ............................................................................................................................................................ 4 Geological setting ............................................................................................................................................. 5 Material and methods ......................................................................................................................................... 6 Cladistic analysis and ordination ............................................................................................................... 8 Skulls ..................................................................................................................................................................... 8 PMO 201.956 ................................................................................................................................................. 8 Comparative material ................................................................................................................................ 8 Description of PMO 201.956 .......................................................................................................................... 10 Systematic paleontology ............................................................................................................................. 10 Figures and drawings .................................................................................................................................. 10 Skull openings and foramina .................................................................................................................... 13 External Nares ........................................................................................................................................... 13 Frontal Foramina ...................................................................................................................................... 13 Orbit ............................................................................................................................................................... 13 Supratemporal fenestrae ....................................................................................................................... 14 Posttemporal fenestrae .......................................................................................................................... 14 Foramen magnum .................................................................................................................................... 14 Skull Roof (Figures 3 and 4) ...................................................................................................................... 14 Premaxilla .................................................................................................................................................... 14 Frontal .......................................................................................................................................................... 15 Postfrontal ................................................................................................................................................... 15 Postorbital ................................................................................................................................................... 15 Jugal ............................................................................................................................................................... 15 Squamosal ................................................................................................................................................... 16 Quadrate ...................................................................................................................................................... 16 Parietal .......................................................................................................................................................... 16 Pterygoid flange ........................................................................................................................................ 17 Posterior view (Figure 5) ........................................................................................................................... 17 Quadrate ramus of the pterygoid ....................................................................................................... 17 Paroccipital processes and exoccipital-opisthotic ....................................................................... 17 Basioccipital and occipital condyle .................................................................................................... 17 Mandible (Figure 6) ...................................................................................................................................... 17 Dentary ......................................................................................................................................................... 17 Angular ......................................................................................................................................................... 18 Coronoid ....................................................................................................................................................... 18 Articular ....................................................................................................................................................... 18 Dentition ...................................................................................................................................................... 18 Cladistic analysis ................................................................................................................................................ 19 2 Characters ........................................................................................................................................................ 19 Differing characters, discussion .............................................................................................................. 20 Placement within the Plesiosauria ......................................................................................................... 21 Relations inside the polycotylid group ................................................................................................. 24 Discussion ............................................................................................................................................................. 27 Comparison with Thililua longicollis Bardet et al. 2003 ................................................................ 27 (Figures 1A-3 and 2A-3) ............................................................................................................................. 27 Comparison with Manemergus anguirostris Buchy et al. 2005 .................................................. 27 (Figures 1A-3 and 2A-3) ............................................................................................................................. 27 Conclusion............................................................................................................................................................. 28 Acknowledgements ........................................................................................................................................... 28 References ............................................................................................................................................................ 29 Appendix A – Taxa and holotypes in O’Keefe (2001) ........................................................................... 34 Appendix B – Taxa and holotypes in O’Keefe (2004) ........................................................................... 35 Appendix C – Data matrix based on O’Keefe (2001) ............................................................................ 36 Appendix D – Data matrix based on O’Keefe (2004) ............................................................................ 46 Appendix E – Abbreviations .......................................................................................................................... 48 Institutional abbreviations ........................................................................................................................ 48 Abbreviations in Buchy et al. 2005......................................................................................................... 49 Abbreviations in Bardet et al. 2003 ....................................................................................................... 49 3 Abstract A Moroccan polycotylid plesiosaur from the early Turonian (Upper Cretaceous) of the Goulmima Formation is described.