''Pleurosaurus'' (meaning "side lizard") is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial no ...

diapsid Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The group first appeared about three hundred million years ...

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates ( lizards and snakes) and rhynchoce ...

s belonging to the group Sphenodontia, extinct relatives of the modern

tuatara Tuatara (''Sphenodon punctatus'') are reptiles endemic to New Zealand. Despite their close resemblance to lizards, they are part of a distinct lineage, the order Rhynchocephalia. The name ''tuatara'' is derived from the Māori language an ...

. ''Pleurosaurus'' fossils were discovered in the Solnhofen Limestone of Bavaria, Germany and Canjuers, France. It contains two species, ''P. goldfussi'' and ''P. ginsburgi''.Dupret, V. (2004). The pleurosaurs: anatomy and phylogeny. ''Revue de Paléobiologie'', 9: 61-8

/ref> ''Pleurosaurus'' is one of the few known aquatic animal, aquatic sphenodontians. Its body was approximately long, and elongated for

hydrodynamic In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids—liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) and ...

streamlining, with comparatively short limbs and a powerful tail. The body was heavily modified from those of other rhynchocephalians, including an elongated triangular skull. It swam via the use of poorly efficient axial undulatory anguilliform locomotion (the movement of the body side to side) in shallow marine environments, and was probably

piscivorous A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evoluti ...

. It had only small limbs, which probably did not aid in swimming, and nostrils placed far back on the head, close to the eyes.

History of discovery

''Pleurosaurus'' was first described from the Solnhofen Limestone by

Christian Erich Hermann von Meyer Christian Erich Hermann von Meyer (3 September 1801 – 2 April 1869), known as Hermann von Meyer, was a German palaeontologist. He was awarded the 1858 Wollaston medal by the Geological Society of London. Life He was born at Frankfurt am M ...

in 1834, based on the species ''Pleurosaurus goldfussi.'' In 1970 fossils were reported from the lithographic limestones in a quarry near the village of Aiguines in the Canjuers plateau, France. In 1974, ''Pleurosaurus ginsburgi'' was described based on MNHN 1983-4-CNJ 67, a mostly complete skeleton found at the Aiguines quarry.

Description

''Pleurosaurus goldfussi'' and ''Pleurosaurus ginsburgi'' are distinguished by differing skull proportions, different numbers of presacral vertebrae, and considerably shorter forelimbs on ''P. ginsburgi.'' Pleurosaurus dorsal

File:Pleurosaurus 783534.jpg File:Pleurosaurus goldfussi 678e.jpg, ''P. goldfussi'' File:Pleurosaurus goldfussi.JPG, ''P. goldfussi'' File:Pleurosaurus ginsburgi 6578.jpg, ''P. ginsburgi''

References

Jurassic lepidosaurs Sphenodontia Solnhofen fauna Prehistoric reptile genera {{paleo-reptile-stub