Glacialisaurus

Glacialisaurus is a genus of massospondylid sauropodomorph dinosaur. It lived during the Early Jurassic period in what is now central Transantarctic Mountains of Antarctica. It is known from the holotype FMNH PR1823, a partial hind limb (foot) and from the referred material FMNH PR1822, a left femur.

Glacialisaurus
Temporal range: Early Jurassic
~189–183 Ma
Glacialisaurus
Holotype foot
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Family: Massospondylidae
Genus: Glacialisaurus
Smith & Pol 2007
Species
  • G. hammeri Smith & Pol 2007 (type)

Discovery

Glacialisaurus2
Restoration of Glacialisaurus

It was discovered and collected in the tuffaceous siltstones and mudstones of the lower part of the Hanson Formation, in Mount Kirkpatrick. It was first named by Nathan Smith and Diego Pol in 2007 and the type species is Glacialisaurus hammeri.[1] The generic name, Glacialisaurus, is derived from the Latin word glacialis, meaning "icy" or "frozen", in reference to the Beardmore Glacier region in the Central Transantarctic Mountains, where the fossil remains were found. The specific name, G. hammeri, honors Dr. William R. Hammer of Augustana College, who made major contributions to both paleontology and Antarctic research.[1][2]

Phylogeny

Glacialisaurus FMNH
Model of G. hammeri, Field Museum of Natural History (smaller specimen is of a not-yet-named prosauropod also from Antarctica.)
Glacialisaurus hammeri
Femur fragment

In their phylogenetic analysis of the relationships of Glacialisaurus, Smith and Pol found that it is a massospondylid, a non-eusauropod sauropodomorph more advanced than other forms such as Saturnalia and Plateosaurus. Features of its foot are similar to Lufengosaurus (from the Early Jurassic of China), and the phylogenetic study suggests that Lufengosaurus may have been a close relative of Glacialisaurus, whereas other massospondylids such as Coloradisaurus and Massospondylus found to be more basal forms.[1] Recent cladistic analyses by Yates (2007), Yates et al. (2010, 2011) and Novas et al. (2011) found the same results.[3][4] The discovery of Glacialisaurus is important to the study of the early distribution of sauropod dinosaurs. The presence of this primitive sauropodomorph in the Hanson Formation (which has also yielded remains attributed to true sauropods) shows that both primitive and advanced members of this lineage existed side by side in the early Jurassic Period.[1][5]

See also

References

  1. ^ a b c d Smith, Nathan D.; Pol, Diego (2007). "Anatomy of a basal sauropodomorph dinosaur from the Early Jurassic Hanson Formation of Antarctica". Acta Palaeontologica Polonica. 52 (4): 657–674.
  2. ^ "A big find". Scientists describe previously undiscovered dinosaur that lived 190 million years ago. The Antarctic Sun. December 20, 2007. Retrieved 2008-01-13.
  3. ^ Yates, Adam M. (2007). "The first complete skull of the Triassic dinosaur Melanorosaurus Haughton (Sauropodomorpha: Anchisauria)". In Barrett, Paul M.; Batten, David J. (eds.). Special Papers in Palaeontology. 77. London: The Palaeontological Assoc. pp. 9–55. ISBN 978-1-4051-6933-2.
  4. ^ Fernando E. Novas; Martin D. Ezcurra; Sankar Chatterjee; T. S. Kutty (2011). "New dinosaur species from the Upper Triassic Upper Maleri and Lower Dharmaram formations of central India". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 101 (3–4): 333–349. doi:10.1017/S1755691011020093.
  5. ^ Smith, N.D.; Makovicky, P.J.; Pol, D.; Hammer, W.R. & Currie, P.J. (2007). "The Dinosaurs of the Early Jurassic Hanson Formation of the Central Transantarctic Mountains: Phylogenetic Review and Synthesis" (PDF). U.S. Geological Survey and the National Academies. 2007 (1047srp003): 5 pp. doi:10.3133/of2007-1047.srp003.
Averostra

Averostra, or "bird snouts", is a clade that includes most theropod dinosaurs that have a promaxillary fenestra (fenestra promaxillaris), an extra opening in the front outer side of the maxilla, the bone that makes up the upper jaw. Two groups of averostrans, the Ceratosauria and the Orionides, survived into the Cretaceous period. When the Cretaceous–Paleogene extinction event occurred, ceratosaurians and two groups of orionideans within the clade Coelurosauria, the Tyrannosauroidea and Maniraptoriformes, were still extant. Only one subgroup of maniraptoriformes, Aves, survived the extinction event and persisted to the present day.

Avetheropoda

Avetheropoda, or "bird theropods", is a clade that includes carnosaurians and coelurosaurs to the exclusion of other dinosaurs.

Cerapoda

Cerapoda ("ceratopsians and ornithopods") is a clade of the dinosaur order Ornithischia.

Coloradisaurus

Coloradisaurus (meaning "Colorados [from Los Colorados Formation] lizard") is a genus of massospondylid sauropodomorph dinosaur. It lived during the Late Triassic period (Norian to Rhaetian stages) in what is now La Rioja Province, Argentina. It is known from the holotype PVL 5904, nearly complete skull. It was discovered and collected from the upper section of the Los Colorados Formation of the Ischigualasto-Villa Unión Basin.

Dinosaur Revolution

Dinosaur Revolution is a four-part American nature documentary produced by Creative Differences. It utilizes computer-generated imagery to portray dinosaurs and other animals from the Mesozoic era. The program was originally aired on the Discovery Channel and Science.

Dinosaur Revolution was released to mixed reviews, with some citing the quality of its animation and a lack of seriousness in its tone as reasons for criticism. It was, however, praised for its educational content and general energy.

Dinosauriformes

Dinosauriformes is a clade of archosaurian reptiles that include the dinosaurs and their most immediate relatives. All dinosauriformes are distinguished by several features, such as shortened forelimbs and a partially to fully perforated acetabulum, the hole in the hip socket traditionally used to define dinosaurs. The oldest known member is Asilisaurus, dating to about 245 million years ago in the Anisian age of the middle Triassic period.

Jeholosauridae

Jeholosaurids were herbivorous neornithischian dinosaurs from the Cretaceous Period (Aptian - Santonian, with a possible Campanian record) of Asia. The family was first proposed by Han et al. in 2012. The jeholosaurids were defined as those ornithischians more closely related to Jeholosaurus shangyuanensis than to Hypsilophodon foxii, Iguanodon bernissartensis, Protoceratops andrewsi, Pachycephalosaurus wyomingensis, or Thescelosaurus neglectus. The Jeholosauridae includes the type genus Jeholosaurus and Yueosaurus.

Jingshanosaurus

Jingshanosaurus (meaning "Jingshan lizard") is a genus of sauropodomorph dinosaurs from the early Jurassic period.

Massospondylidae

Massospondylidae is a family of early massopod dinosaurs that existed in Asia, Africa, South America and Antarctica during the Late Triassic to the Early Jurassic periods. Several dinosaurs have been classified as massospondylids over the years. The largest cladistic analysis of early sauropodomorphs, which was presented by Apaldetti and colleagues in November 2011, found Adeopapposaurus, Coloradisaurus, Glacialisaurus, Massospondylus, Leyesaurus and Lufengosaurus to be massospondylids. This result supports many previous analyses that tested fewer taxa. However, this analysis found the two recently described North American massopods, Sarahsaurus and Seitaad, and the South African Ignavusaurus to nest outside Massospondylidae, as opposed to some provisional proposals. Earlier in 2011, Pradhania, a sauropodomorph from India, was tested for the first time in a large cladistic analysis and was found to be a relatively basal massospondylid. Mussaurus and Xixiposaurus may also be included within Massospondylidae. In 2019, a specimen previously assigned to Massospondylus from South Africa was re-examined and found to belong to a separate genus that was named Ngwevu.

Melanorosauridae

The Melanorosauridae were a family of sauropodomorph dinosaurs which lived during the Late Triassic and Early Jurassic. The name Melanorosauridae was first coined by Friedrich von Huene in 1929. Huene assigned several families of dinosaurs to the infraorder "Prosauropoda": the Anchisauridae, the Plateosauridae, the Thecodontosauridae, and the Melanorosauridae. Since then, these families have undergone numerous revisions. Galton and Upchurch (2004) considered Camelotia, Lessemsaurus, and Melanorosaurus members of the family Melanorosauridae. A more recent study by Yates (2007) indicates that the melanorosaurids were instead early sauropods.

Mount Kirkpatrick

Mount Kirkpatrick is a lofty, generally ice-free mountain in Antarctica's Queen Alexandra Range. Located 8 km (5 mi) west of Mount Dickerson, Mt. Kirkpatrick is the highest point in the Queen Alexandra Range, as well as in its parent range, the Transantarctic Mountains. Discovered and named by the British Antarctic Expedition (1907–09), the mountain was named for a Glasgow businessman, who was one of the original supporters of the expedition. Mount Kilpatrick is an alternate name for this mountain.

Mussaurus

Mussaurus (meaning "mouse lizard") is a genus of herbivorous sauropodomorph dinosaur that lived in southern Argentina during the Late Triassic, about 215 million years ago. It receives its name from the small size of the skeletons of juvenile and infant individuals, which were once the only known specimens of the genus. However, since Mussaurus is now known from adult specimens, the name is something of a misnomer; adults possibly reached 6 metres (20 ft) in length and weighed more than 1,000 kilograms (2,200 lb). Mussaurus possesses anatomical features suggesting a close, possibly transitional evolutionary relationship with true sauropods.

Neotheropoda

Neotheropoda (meaning "new theropods") is a clade that includes coelophysoids and more advanced theropod dinosaurs, and the only group of theropods who survived the Triassic–Jurassic extinction event. Yet all of the neotheropods became extinct during the early Jurassic period except for Averostra.

Orionides

Orionides is a clade of tetanuran theropod dinosaurs from the Middle Jurassic to the Present. The clade includes most theropod dinosaurs, including birds.

Orodrominae

Orodrominae is a subfamily of parksosaurid dinosaurs from the Cretaceous of North America and Asia.

Riojasauridae

Riojasauridae is a family of sauropod-like dinosaurs from the Upper Triassic. It is known primarily from the genera Riojasaurus and Eucnemesaurus. Sites containing Riojasauridae include the Lower Elliot Formation of Orange Free State, South Africa (where fossils of Eucnemesaurus have been found), and Ischigualasto, in La Rioja Province, Argentina ( where fossils of Riojasaurus have been recovered).

Sarahsaurus

Sarahsaurus is a genus of basal sauropodomorph dinosaur which lived during the lower Jurassic period in what is now northeastern Arizona, United States.

William R. Hammer

William Roy Hammer is an American paleontologist who is credited with the discovery of the first carnivorous dinosaur unearthed in Antarctica, Cryolophosaurus, in 1991. He was professor of geology and curator of the Frxyell Geology Museum at Augustana College in Rock Island, IL from 1981-2017.

Xixiposaurus

Xixiposaurus is a genus of prosauropod dinosaur which existed in what is now Lower Lufeng Formation, China during the lower Jurassic period. It was first named by Sekiya Toru in 2010 and the type species is Xixiposaurus suni.

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