This article needs additional citations for verification .(May 2016) |
Palaeosaurus Temporal range: Late Triassic, ~ | |
---|---|
Teeth BRSMG *Ca7449/4 (left) and BRSMG *Ca7448/3 (right) - of which both comprise the holotype | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Archosauromorpha |
Clade: | Archosauriformes |
Clade: | Archosauria |
Genus: | † Palaeosaurus Riley and Stutchbury, 1836 |
Type species | |
†Palaeosaurus cylindrodon Riley and Stutchbury, 1840 | |
Synonyms | |
|
Palaeosaurus (or Paleosaurus) is a genus of indeterminate archosaur known from two teeth found in the Bromsgrove Sandstone Formation and also either the Magnesian Conglomerate or the Avon Fissure Fill of Clifton, Bristol, England (originally Avon). [1] It has had a convoluted taxonomic history. [2]
Richard Owen's mistake of associating prosauropod skeletal remains with the carnivorous teeth which Riley and Stutchbury called Palaeosaurus, combined with Friedrich von Huene's Teratosaurus minor, which was also a combination of carnivore and prosauropod remains, led paleontologists to view prosauropods as carnivorous animals for quite a long time. This error made it into several textbooks and other dinosaur reference works. [2]
In the autumn of 1834, surgeon Henry Riley (1797–1848) [3] and the curator of the Bristol Institution, Samuel Stutchbury (15 January 1798 – 12 February 1859), began to excavate "saurian remains" at the quarry of Durdham Down, at Clifton, presently a part of Bristol, which is part of the Magnesian Conglomerate. In 1834 and 1835, they briefly reported on the finds. [4] They provided their initial description in 1836, naming two new genera: Palaeosaurus and Thecodontosaurus . [1] In 1836 Riley and Stutchbury briefly and informally published on two new fossil teeth (the holotype tooth of P. platyodon is listed under BRSMG *Ca7448/3 and the holotype tooth of P. cylindrodon is listed under BRSMG *Ca7449/4. Both are now listed under the latter species) found in or near the city of Bristol, England, which they called Palaeosaurus cylindrodon and Palaeosaurus platyodon. [1] [5] Riley and Stutchbury did not mean to assign these species to Saint-Hilaire's genus of teleosaurids; they simply did not know the name had been used. Thecodontosaurus was also named in this publication. Only in 1840 do Riley and Stutchbury fully describe their two species of Palaeosaurus, each based on a single sharp tooth from the Late Triassic Period. The spellings were then corrected to read Paleosaurus cylindrodon and Paleosaurus platyodon.
In 1842, Sir Richard Owen created the name Dinosauria. In the same publication, he attempted to redescribe Riley and Stutchbury's Paleosaurus and Thecodontosaurus, which he did not consider to be dinosaurs. Not knowing of the change in spelling, he changed the name back to Palaeosaurus, and this spelling was followed by all subsequent authors until 1959. Owen assigns other bones to Palaeosaurus, which would later be re-classified to the prosauropod dinosaur Thecodontosaurus. Contrary to Owen, in 1870, Thomas Henry Huxley described both Thecodontosaurus and Palaeosaurus as dinosaurs for the first time. He considered Palaeosaurus platyodon to be synonymous with Thecodontosaurus antiquus, most likely due to the Thecodontosaurus bones that Owen assigned to the former genus. However, Huxley regarded P. cylindrodon as an unrelated carnivorous theropod.
American paleontologist Edward Drinker Cope named a third species, Palaeosaurus fraserianus, in 1878, for an isolated tooth found in Triassic rocks in Pennsylvania. Today these are regarded as belonging to an indeterminate sauropodomorph dinosaur unrelated to Palaeosaurus. [6] In 1881, a fourth species is created, Palaeosaurus stricklandi; these are now recognized to be those of a phytosaur. [7]
Von Huene, in 1908, recognized the tooth of Palaeosaurus platyodon belonged to a phytosaur and placed it into the new genus Rileya, forming the new combination Rileya platyodon .
One of the holotype teeth of P. cylindrodon, presumably BRSMG *Ca7448/3, was destroyed during World War II, in 1940. The other tooth survives to this day.
In 1959 German paleontologist Oskar Kuhn, for the first time since 1840, recognized that the genus Palaeosaurus created by Riley and Stutchbury in 1836 was preoccupied and created the new generic name Palaeosauriscus to contain Palaeosaurus cylindrodon and all other species that had previously been described under Palaeosaurus.
In 1964, Owen's mis-classified specimens caused American Edwin Harris Colbert to classify prosauropods into two groups – Palaeosauria, which included Palaeosaurus and Teratosaurus, thought to be carnivorous because of the chimaeric nature of Palaeosaurus; and Plateosauria, which included Thecodontosaurus and Plateosaurus , which had been described with the correct skulls, and therefore were correctly described as a herbivorous group.
Thecodontosaurus was redescribed by a team of paleontologists led by Michael Benton in 2000, which placed Owen's mis-classified material under the genus Thecodontosaurus rather than Palaeosaurus, and this is still followed today. Most of the skeletal bones ever assigned to Palaeosaurus cylindrodon and P. platyodon were also reassigned to Thecodontosaurus. The genera Rileya and Palaeosauriscus, as well as the species Palaeosaurus cylindrodon and Palaeosaurus platyodon, were all declared nomina dubia.
In 2007, Peter Galton, reviewing the archosaurian fossils of the 1834 Bristol finds, reaffirmed the identification of the two teeth and humeri of Palaeosaurus platyodon (Rileya) as belonging to a phytosaur, and regarded P. cylindrodon (Palaeosauriscus) as an indeterminate archosaur. He agreed with Benton that Rileya is dubious, but suggested that Palaeosauriscus may be valid, based on its now-destroyed tooth with a "subcircular cross-section and fine, obliquely inclined denticles". [2]
In 1932, Von Huene assigned new material to Palaeosaurus; numerous prosauropod bones found in Germany. Because of Owen's Thecodontosaurus bones misassigned to Palaeosaurus cylindrodon, the species was thought to be a prosauropod. Von Huene therefore referred his new species to Palaeosaurus, creating the name P. diagnostica.
In 1973, Peter Galton, a British paleontologist, moved the species into its own genus, creating the new combination Efraasia diagnosticus. For several decades, most scientists considered Efraasia a junior synonym of Sellosaurus; however, in 2003 Adam Yates, another British palaeontologist, redescribed the bones assigned to Sellosaurus. He resurrected the genus Efraasia for some of these bones, to which he also assigned the bones that had been first described as Teratosaurus minor as well (although leaving out the teeth, which were recognized as non-dinosaurian). Like Galton in 1973, Yates's Efraasia also included the remains previously known as Palaeosaurus diagnosticus, although unlike Galton, Yates calls the species Efraasia minor, synonymizing both species. E. minor was claimed to have priority because von Huene described Teratosaurus minor several pages before Palaeosaurus diagnosticus in his 1908 publication. The name minor therefore would take precedence over diagnostica for this species.
Type species: "Palaeosaurus" cylindrodon (nomen dubium) Riley and Stutchbury 1836 (an indeterminate archosauromorph later renamed the type species of Palaeosauriscus cylindrodon, as Palaeosaurus was pre-occupied) [8]
Other species:
Megalosaurus is an extinct genus of large carnivorous theropod dinosaurs of the Middle Jurassic Epoch of southern England. Although fossils from other areas have been assigned to the genus, the only certain remains of Megalosaurus come from Oxfordshire and date to the late Middle Jurassic.
Thecodontosaurus is a genus of herbivorous basal sauropodomorph dinosaur that lived during the late Triassic period.
Agrosaurus is a potentially dubious genus of thecodontosaurid sauropodomorph probably originating from the Magnesian Conglomerate of England that was originally believed to be a Triassic prosauropod from Australia. Agrosaurus would thus be the oldest dinosaur from that country. However, this appears to have been an error, and the material actually appears to come from Thecodontosaurus or a Thecodontosaurus-like animal from Bristol, England. The type species is Agrosaurus macgillivrayi.
Liliensternus is an extinct genus of basal neotheropod dinosaur that lived approximately 210 million years ago during the latter part of the Triassic Period in what is now Germany. Liliensternus was a moderate-sized, bipedal, ground-dwelling carnivore, that could grow up to 5.15 m (16.9 ft) long. It is the best represented Triassic theropod from Europe and one of the largest known.
Lexovisaurus is a genus of stegosaur from mid-to-Late Jurassic Europe, 165.7-164.7 mya. Fossils of limb bones and armor fragments have been found in middle to late Jurassic-aged strata of England and France.
Fulgurotherium is a dubious genus of ornithischian dinosaur from the Late Cretaceous (Cenomanian) Griman Creek Formation. It lived in what is now Australia.
Gryponyx is an extinct genus of massopod sauropodomorph known from southern Free State, central South Africa.
Chinshakiangosaurus is a genus of dinosaur and probably one of the most basal sauropods known. The only species, Chinshakiangosaurus chunghoensis, is known from a fragmentary skeleton found in Lower Jurassic rocks in China. Chinshakiangosaurus is one of the few basal sauropods with preserved skull bones and therefore important for the understanding of the early evolution of this group. It shows that early sauropods may have possessed fleshy cheeks.
Teratosaurus is a genus of rauisuchians known from the Triassic Stubensandstein of Germany. It is estimated to be 6.2 meters (20.35 ft) long.
Efraasia is a genus of basal sauropodomorph dinosaur. It was a herbivore which lived during the middle Norian stage of the Late Triassic, around 210 million years ago, in what is now Germany. It was named in 1973 after Eberhard Fraas, who during the early twentieth century collected what were the original type specimens.
Dysganus (dis-GANN-us) is a dubious genus of ceratopsian dinosaur from the Campanian stage of the Late Cretaceous. The fossil teeth referred to Dysganus were first collected by Charles Sternberg from the Cretaceous Judith River Formation of Montana and later described by Edward Drinker Cope. All of the species are now seen as dubious Ceratopsians, though referred material from tyrannosaurids and hadrosaurids were found in New Mexico.
Ruehleia is a genus of sauropodomorph dinosaur from the Late Triassic period of Germany. The type species is R. bedheimensis, described by Galton in 2001, and is named for the German paleontologist Hugo Rühle von Lilienstern. Discovered in 1952, the holotype consists of one nearly complete skeleton, including cervical (neck), dorsal (back), and caudal (tail) vertebrae; a partial sacrum; a scapulocoracoid; pelvic bones; most limb bones; and a partially complete manus (hands).
Rileyasuchus is a genus of phytosaur from the Rhaetian Magnesian Conglomerate of England. It has a confusing history, being associated with the taxonomy of Palaeosaurus and Thecodontosaurus, and being a replacement name for a preoccupied genus.
Sphenosaurus is a poorly known genus of procolophonid, a type of prehistoric reptile from the Late Permian Buntsanstein of Germany. Originally assigned the name Palaeosaurus sternbergii, by German paleontologist Leopold Joseph Fitzinger in 1840, the generic name was already preoccupied by not one but two other reptiles assigned the name Palaeosaurus. In 1847, Hermann von Meyer recognized the original 1833 and 1836 usages of Palaeosaurus and moved P. sternbergii to a new genus, Sphenosaurus.
Samuel Stutchbury was an English naturalist and geologist. Alongside Henry Riley, Stutchbury was the co-discoverer of Thecodontosaurus, which in 1836 was the fourth dinosaur genus to be named. He also played a part in Gideon Mantell's naming of Iguanodon. As a geological surveyor he mapped a large area of eastern Australia.
Thecodontosauridae is a family of basal sauropodomorph dinosaurs that are part of the Bagualosauria, known from fossil remains found exclusively in the Magnesian Conglomerate of Bristol, England, which dates back to the Rhaetian stage of the Late Triassic. Two genera are known: Agrosaurus and Thecodontosaurus; the former is often considered to be the same animal as the latter.
Asylosaurus is a genus of basal sauropodomorph dinosaur from the Late Triassic Avon Fissure Fill of England. It is based on partial remains, discovered in the autumn of 1834, described in 1836 by Henry Riley and Samuel Stutchbury as pertaining to Thecodontosaurus, that Othniel Charles Marsh brought to Yale University between 1888 and 1890. These remains thus escaped destruction by a bombardment in 1940 during World War II, unlike the original holotype of Thecodontosaurus. Asylosaurus was described in 2007 by Peter Galton. The type species is A. yalensis, referring to Yale. The bones originally came from a Rhaetian-age cave fill at Durdham Down, Clifton, Bristol.
The Magnesian Conglomerate is a geological formation in Clifton, Bristol in England, Gloucestershire and southern Wales, present in Tytherington, Durdham Down, Slickstones Quarry and Cromhall Quarry.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1836.
Henry Riley (1797–1848) was a British surgeon, anatomist, naturalist, geologist and paleontologist. He is notable for being the co-discoverer and co-describer of the archosaur Palaeosaurus and the dinosaur Thecodontosaurus.