• Corpus ID: 82936031

A Cladistic Analysis and Taxonomic Revision of the Plesiosauria (Reptilia: Sauropterygia)

  title={A Cladistic Analysis and Taxonomic Revision of the Plesiosauria (Reptilia: Sauropterygia)},
  author={F. Robin O'Keefe},
  • F. O'Keefe
  • Published 2001
  • Environmental Science, Geography
The Plesiosauria (Reptilia: Sauropterygia) is a group of Mesozoic marine reptiles known from abundant material, with specimens described from all continents. The group originated very near the Triassic–Jurassic boundary and persisted to the endCretaceous mass extinction. This study describes the results of a specimen-based cladistic study of the Plesiosauria, based on examination of 34 taxa scored for 166 morphological characters. The Pliosauroidea is found to by polyphyletic due to the… 


A phylogenetic analysis places Plesiopterys as the sister group of the Plesiosauroidea, and as such the taxon is the most basal taxon yet known on the branch leading to this major clade.

Phylogenetic relationships of Upper Jurassic (Middle Volgian) plesiosaurians (Reptilia: Sauropterygia) from the Agardhfjellet Formation of central Spitsbergen, Norway

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.

New information on Bobosaurus forojuliensis (Reptilia: Sauropterygia): implications for plesiosaurian evolution

Bobosaurus shows that the evolution of the plesiosaurian body plan from the ancestral pistosauroid grade was a step-wise process, and that some of the vertebral and appendicular specialisations of Jurassic and Cretaceous plesioaurians had already developed in the earliest Late Triassic.

Two new species of long-necked plesiosaurians (Reptilia: Sauropterygia) from the Upper Jurassic (Middle Volgian) Agardhfjellet Formation of central Spitsbergen

The Middle Volgian age of this material helps to bridge the temporal and morphological gap between better known Middle and Late Jurassic plesiosaurians from Europe and Late Cretaceous taxa primarily known from North America.

Anatomy of Colymbosaurus megadeirus (Reptilia, Plesiosauria) from the Kimmeridge Clay Formation of the U.K., and High Diversity Among Late Jurassic Plesiosauroids

Substantial differences between the atlas-axis complexes and cervical vertebrae of Kimmerosaurus langhami, ‘Plesiosaurus’ manselii, C. megadeirus, and specimens referred here to cf.


A detailed re-description and revised diagnosis is given for Macroplata tenuiceps Swinton, 1930, a ple- siosaurian known from a single almost complete specimen (BMNH R5488) from the Blue Lias

Revision of polycotylid plesioaur systematics (sauropterygia plesiosauria) and description of the axial osteology of a juvenile polycotylid

A phylogenetic analysis incorporating a large taxon sampling from the Polycotylidae was used to parse out the evolutionary relationships among the taxa, and revealed that the two Wallace Ranch specimens form a well-supported clade, and feature a mosaic of character states found in currently described species, and may represent a new species.

The Anatomy and Taxonomy of Macroplata tenuiceps (Sauropterygia, Plesiosauria) from the Hettangian (Lower Jurassic) of Warwickshire, United Kingdom

ABSTRACT A detailed re-description and revised diagnosis is given for Macroplata tenuiceps Swinton, 1930, a plesiosaurian known from a single almost complete specimen (BMNH R5488) from the Blue

Osteology of Yunguisaurus Cheng et al., 2006 (Reptilia; Sauropterygia), a Triassic Pistosauroid from China

Detailed comparison revealed morphological differences in various parts of the postcranial, suggesting that Yunguisaurus was not necessarily comparable to the Plesiosauria in terms of body plan and mode of swimming.



A juvenile plesiosaur (Plesiosauria: Reptilia) from the Lower Lias (Hettangian: Lower Jurassic) of Lyme Regis, England: a pliosauroid-plesiosauroid intermediate?

A partial skull and skeleton of a small, juvenile plesiosaur from Lyme Regis, England is described and is thought to have been a predator on soft-bodied or lightly armoured prey, such as belemnoids, ammonites or small fish.

A new pistosaurid (Reptilia: Sauropterygia) from the Middle Triassic of Nevada and its implications for the origin of the plesiosaurs

ABSTRACT We describe a new pistosaurid sauropterygian, Augustasaurus hagdorni, gen. et sp. nov., from the Middle Triassic of Nevada. The specimen was collected in Muller Canyon, Augusta Mountains,

Cranial Anatomy of the Lower Jurassic Pliosaur Rhomaleosaurus megacephalus (Stutchbury) (Reptilia: Plesiosauria)

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.

Morphological and Taxonomic Clarification of the Genus Plesiosaurus

Taxonomy and taphonomy of Rhomaleosaurus zetlandicus (Plesiosauria, Reptilia) from the Toarcian (Lower Jurassic) of the Yorkshire coast

  • M. Taylor
  • Environmental Science, Geography
  • 1992
SUMMARY The holotype skeleton of the large-headed, short-necked plesiosaur Plesiosaurus zetlandicus Phillips, in Anon., 1854 comes from the Toarcian of the Yorkshire coast and has been housed in the

The braincases of Simosaurus and Nothosaurus: Monophyly of the Nothosauridae (Reptilia: Sauropterygia)

The braincase of two acid-prepared specimens of Nothosaurus is described in detail and compared to the brain case of Simosaurus, the sister-group of the Nothosauridae and Cymatosaurus, which are characterized by an extreme dorsoventral flattening of the temporal region of the skull.

Turtles as diapsid reptiles

The result robustly supports the diapsid affinities of turtles, and so requires reassessment of the use of turtles as 'primitive' reptiles in phylogenetic reconstruction, and illustrates the difficulties of treating groups that have extant members with peculiar morphologies that mask phylogenetic affinity.

On a new Species of Plesiosaurus (P. Conybeari) from the Lower Lias of Charmouth; with Observations on P. megacephalus, Stutchbury, and P. brachycephalus, Owen

  • W. J. Sollas
  • Geology
    Quarterly Journal of the Geological Society of London
  • 1881
The nearly complete and very fine specimen of Plesiosaurus (Pl. XXIII. fig. 1) which forms the subject of the present paper is the latest addition to the already large collection of fossil reptiles

The Nothosaur Pachypleurosaurus and the Origin of Plesiosaurs

It is concluded that the transition between primitive terrestrial diapsids and plesiosaurs occurred via a succession of changes in patterns of aquatic locomotion and Pachypleurosaurus has the greatest degree of development of the anterior portion of the shoulder girdle, suggesting that the recovery stroke was of considerable importance.

New plesiosaurs from the Upper Cretaceous of Antarctica

  • S. ChatterjeeB. Small
  • Geography, Environmental Science
    Geological Society, London, Special Publications
  • 1989
Abstract New plesiosaur remains from the Upper Cretaceous Lopez de Bertodano Formation (late Campanian-Maastrichtian) of Seymour Island, Antarctic Peninsula include Cryptoclididae and Elasmosauridae.