The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: implications for plesiosaur phylogenetics

@article{Smith2008TheSO,
  title={The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: implications for plesiosaur phylogenetics},
  author={Adam S. Smith and Gareth J. Dyke},
  journal={Naturwissenschaften},
  year={2008},
  volume={95},
  pages={975-980}
}
The predatory pliosaurs were among the largest creatures ever to inhabit the oceans, some reaching gigantic proportions greater than 15 m in length. Fossils of this subclade of plesiosaurs are known from sediments all over the world, ranging in age from the Hettangian (approximately 198 Myr) to the Turonian (approximately 92 Myr). However, due to a lack of detailed studies and because only incomplete specimens are usually reported, pliosaur evolution remains poorly understood. In this paper, we… 
A Giant Pliosaurid Skull from the Late Jurassic of England
TLDR
The authors' data support a trend of decreasing length of the mandibular symphysis through Late Jurassic time, as previously suggested, and may be correlated with increasing adaptation to feeding on large prey.
Youngest Occurrences of Rhomaleosaurid Plesiosaurs Indicate Survival of an Archaic Marine Reptile Clade at High Palaeolatitudes
Rhomaleosaurid plesiosaurians were a common and ecologically significant component of Early Jurassic marine faunas, primarily as large-bodied predators. They declined in abundance and made their last
High Diversity, Low Disparity and Small Body Size in Plesiosaurs (Reptilia, Sauropterygia) from the Triassic–Jurassic Boundary
TLDR
High rhomaleosaurid diversity immediately following the Triassic-Jurassic boundary supports the gradual model of Late Triassic extinctions, mostly predating the boundary itself.
Phylogenetic relationships of Upper Jurassic (Middle Volgian) plesiosaurians (Reptilia: Sauropterygia) from the Agardhfjellet Formation of central Spitsbergen, Norway
TLDR
The phylogenetic relationships of these five taxa were investigated based on data sets previously constructed for global plesiosaurian relationships, and yielded a tree topology closely conforming to the traditional plesioauroid and pliosauroid dichotomy, nesting Leptocleidia within the latter.
A New Species of Pliosaurus (Sauropterygia, Plesiosauria) from the Upper Jurassic of Northwestern Patagonia, Argentina
TLDR
This new record reinforces the hypothesis of a trend toward the shortening of the mandibular symphysis observed in late Kimmeridgian—Tithonian species from the northern hemisphere and may be interpreted as the result of predatory and/or reproductive behaviors.
Osteology of Rhomaleosaurus Thorntoni (Sauropterygia: Rhomaleosauridae) from the Lower Jurassic (Toarcian) of Northamptonshire, England
ABSTRACT This paper describes the holotype of Rhomaleosaurus thorntoni (NHMUK PV R4853) from the upper part of the Whitby Mudstone Formation (Toarcian) of Kingsthorpe Hollow, Northamptonshire,
Cranial Anatomy of Thalassiodracon hawkinsii (Reptilia, Plesiosauria) from the Early Jurassic of Somerset, United Kingdom
TLDR
The relatively long neck and small skull of Thalassiodracon indicate that the robust skeleton and macropredaceous habits of rhomaleosaurids and pliosaurids were derived independently.
A new record of the pliosaur Brachauchenius lucasi Williston, 1903 (Reptilia: Sauropterygia) of Turonian (Late Cretaceous) age, Morocco
Abstract The site of Goulmima (south Morocco) is well known for its rich marine fauna of Turonian age (Late Cretaceous). It has yielded a large variety of invertebrates but also of vertebrate taxa,
The Anatomy of Stratesaurus (Reptilia, Plesiosauria) from the Lowermost Jurassic of Somerset, United Kingdom
TLDR
One of the oldest plesiosaurians, Stratesaurus taylori from the earliest Hettangian of the United Kingdom, is provided, due to its plesiomorphic morphology and well-characterized anatomy, to be recommended as an ingroup representative of Plesiosauria for future cladistic analyses of Triassic sauropterygians.
...
...

References

SHOWING 1-10 OF 24 REFERENCES
First occurrence of a gigantic pliosaurid plesiosaur in the late Jurassic (Kimmeridgian) of Mexico
Reinvestigation of a partial vertebral column from the Kimmeridgian La Caja Formation of Mexico, housed in the University of Linares (Mexico), and previously attributed to a dinosaur, proves to be
A Cladistic Analysis and Taxonomic Revision of the Plesiosauria (Reptilia: Sauropterygia)
TLDR
The Plesiosauria is found to by polyphyletic due to the inclusion of the Polycotylidae; this second clade is instead a member of the Plesiosauroidea, and thus more closely related to elasmosaurs than to other ‘pliosaurs’.
An archaic crested plesiosaur in opal from the Lower Cretaceous high-latitude deposits of Australia
TLDR
Umoonasaurus is surprisingly archaic despite its relatively late age—being simultaneously the most basal (primitive) and last surviving rhomaleosaurid; thus, reinforcing the suspected convergent evolution of the ‘pliosauromorph’ hypercarnivore body plan.
Cranial Anatomy of the Lower Jurassic Pliosaur Rhomaleosaurus megacephalus (Stutchbury) (Reptilia: Plesiosauria)
TLDR
Comparison of R. megacephalus with the Upper Liassic species, Rhomaleosaurus zetlandicus, shows that the former has a more gracile snout and a shallower lower jaw symphysis, and lacks squamosal-quadrate foramina.
The evolution of plesiosaur and pliosaur morphotypes in the Plesiosauria (Reptilia: Sauropterygia)
  • F. O’Keefe
  • Geography, Environmental Science
    Paleobiology
  • 2002
Abstract The dichotomy between short-necked, large-headed “pliosaurs” and long-necked, small-headed “plesiosaurs” has formed the basis of plesiosaur taxonomy for over one hundred years. Recent work
Functional anatomy of the head of the large aquatic predator Rhomaleosaurus zetlandicus (Plesiosauria, Reptilia) from the Toarcian (Lower Jurassic) of Yorkshire, England
The skull and mandible of the type specimen of the large pliosauroid plesiosaur Rhomaleosaurus zetlandicus from the Toarcian of England are elongate, and adapted for powerful predatory activity in
Note on some of the Generic Modifications of the Plesiosaurian Pectoral Arch
  • H. Seeley
  • Geography
    Quarterly Journal of the Geological Society of London
  • 1874
If not having a sternum the Plesiosauria differ from the Crocodilia and from all the Lacertian orders of Reptiles. Serpents with limbs being as yet undiscovered, the only true Reptilia which admit of
The nature of the shoulder girdle and clavicular arch in sauropterygia
  • H. Seeley
  • Medicine
    Proceedings of the Royal Society of London
  • 1892
The Sauropterygia and Ichthyosauria having formerly been combined in the group termed Nexipoda or Enaliosauria, it has been rather assumed than proved that the bones which form the shoulder girdle in
The genera of reptiles
  • Palaeobiologica
  • 1928
...
...