Jeffrey A. Wilson

Jeffrey A. Wilson also known as "JAW" is a professor of geological sciences and assistant curator at the Museum of Paleontology at the University of Michigan.

His doctoral dissertation was on sauropod evolution and phylogeny, and he has continued this work in cladistic analysis and revision of the group (see e.g. Wilson and Sereno 1994, 1998, Wilson 2005b, and especially Wilson 2002). With Paul Sereno, he defined the clades Macronaria and Somphospondyli (Wilson & Sereno 1998).

Wilson was also involved in the discovery and description of Pabwehshi pakistanensis, the first discovery of decent (diagnostic) Cretaceous crocodylian fossil remains from the Indian subcontinent, in the discovery of Rajasaurus narmadensis, the most completely known theropod dinosaur from India and a member of the family Abelisauridae, description of a number of North African dinosaurs (theropods and sauropods) from Niger, and rediscriptions of the Cretaceous sauropods Titanosaurus colberti (as Isisaurus) and Nemegtosaurus (previously thought to be a diplodocoid, but now recognised as a titanosaur).

His younger brother, Dr. Gregory P. Wilson, studies Mesozoic mammals and is currently an assistant professor in the Department of Biology at the University of Washington, and adjunct curator of vertebrate paleontology at the Burke Museum of Natural History and Culture.

List of dinosaurs named

Bibliography

  • Wilson, J. A. and Sereno, P. C. (1994) Higher-level phylogeny of sauropod dinosaurs. Journal of Vertebrate Paleontology, Supplement 14:52A.
  • Wilson, J.A. & Sereno, P.C. (1998). Early evolution and Higher-level phylogeny of sauropod dinosaurs. Society of Vertebrate Paleontology, Memoir 5, 1-68. (includes definitions of the clades Macronaria and Somphospondyli)
  • Sereno, P. C., Beck, A.L., Dutheil, D.B., Gado, B., Larsson, H.C.E., Lyon, G.H., Marcot, J. D., Rauhut, O. W. M., Sadleir, R.W., Sidor, C.A., Varricchio, D.J., Wilson, G. P. & Wilson, J. A. 1998. A long-snouted predatory dinosaur from Africa and the evolution of spinosaurids. Science 282:1298-1302. document in pdf format (description of Suchomimus, and spinosaur relationships)
  • Wilson, J. A. and M. T. Carrano, (1999). Titanosaurs and the origin of 'wide-gauge' trackways: a biomechanical and systematic perspective on sauropod locomotion. Paleobiology 25:252-267. (Titanosaurs had a different gait to earlier sauropods - the legs are spaced further apart, may have facilitated tripodal feeding)
  • Wilson, J. A., R. N. Martinez & O. Alcober. (1999). Distal tail segment of a titanosaur (Dinosauria: Sauropoda) from the Upper Cretaceous of Mendoza, Argentina. Journal of Vertebrate Paleontology 19:591-594.
  • Wilson, J A. (1999). A nomenclature for vertebral laminae in sauropods and other saurischian dinosaurs. Journal of Vertebrate Paleontology 19(4):639-653. (vertebral laminae can play an important role in sauropod classification)
  • Wilson, J.A. (1999) The evolution and phylogeny of sauropod dinosaurs. Ph.D. dissertation, University of Chicago, 384pp [in 2 vols.]
  • Sereno, P.C., Beck, A.L., Dutheil, D.B., Larsson, H.C.E., Lyon, G.H., Moussa, B., Sadleir, R.W., Sidor, C.A., Varricchio, D.J., Wilson, G. P. & Wilson, J. A., (1999), Cretaceous Sauropods from the Sahara and the Uneven Rate of Skeletal Evolution Among Dinosaurs, Science 286(5443): 1342-1347 (Nov 12 1999) (describes two new African sauropods: Jobaria tiguidensis, a late persisting primitive sauropod, and Nigersaurus taqueti, a Rebbachisaur))
  • Wilson, J.A., Malkani, M.S., and Gingerich, P.D. (2001) New crocodyliform (Reptilia, Mesoeucrocodylia) from the Upper Cretaceous Pab Formation of Vitakri, Balochistan (Pakistan). Contributions from the Museum of Paleontology, University of Michigan 30(12): 321-336. (on Pabwehshi pakistanensis)
  • Wilson, J.A. (2002) Sauropod dinosaur phylogeny: critique and cladistic analysis, Zoological Journal of the Linnean Society 136(2):215-275 (a detailed cladistic analysis of sauropod phylogeny)
  • Wilson, J.A. and Upchurch, P (2003) A revision of Titanosaurus Lydekker (Dinosauria-Sauropoda), the first dinosaur genus with a "Gondwanan" distribution, Journal of Systematic Palaeontology Volume 1 Issue 3 - September 2003 (a revision of 14 species of the genus Titanosaurus shows that only five of these are valid. The type species T. indicus is considered a nomen dubium, and therefore the abandonment of suprageneric taxa based on it - e.g. Titanosaurinae, Titanosauridae, and Titanosauroidea - is suggested. The species T. colberti is renamed Isisaurus colberti)
  • Wilson, J.A., Sereno, P.C., Srivastava, S., Bhatt, D.K., Khosla, A. and Sahni, A. (2003) A new abelisaurid (Dinosauria, Theropoda) from the Lameta Formation (Cretaceous, Maastrichtian) of India. Contributions from the Museum of Paleontology, University of Michigan 31(1):1-42 (description of Rajasaurus narmadensis)
  • Wilson, J.A. (2005). Redescription of the Mongolian sauropod Nemegtosaurus mongoliensis Nowinski (Dinosauria: Saurischia) and comments on Late Cretaceous sauropod diversity. Journal of Systematic Palaeontology 3: 283-318. (shows that Nemegtosaurus and Quaesitosaurus are closely related and belong to the titanosaur group, rather than the diplodocoidea; redefines the family Nemegtosauridae. See New Nemegtosaurus paper for more.
  • Curry Rogers, K. A. and Wilson, J.A. 2005, The Sauropods: Evolution and Paleobiology, University of California Press, Berkeley, ISBN 0-520-24623-3
  • Wilson, J.A. (2005b) "Overview of Sauropod Phylogeny and Evolution", in The Sauropods: Evolution and Paleobiology (broad overview of phylogenetic characteristics and evolution development of the main sauropod clades, also phylocode-style definitions for each clade.
  • Wilson, J. A. and Sereno, P. C. (2005) "Structure and Evolution of a Sauropod Tooth Battery" in The Sauropods: Evolution and Paleobiology (Nigersaurus skull and dentition, illustrating Rebbachisaur feeding adaptations)
2003 in paleontology

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 2003.

Argyrosaurus

Argyrosaurus ( AR-jy-ro-SOR-əs) is a genus of herbivorous titanosaurian sauropod dinosaur that lived about 90 million years ago, during the Late Cretaceous Period of what is now Argentina.

Dyslocosaurus

Dyslocosaurus (meaning "hard-to-place lizard") is the name given in 1992 to a genus of sauropod dinosaur from the Late Jurassic Period of Wyoming, North America.

The holotype or type specimen the genus is based on, AC 663, is part of the collection of the Amherst College Museum of Natural History. It was collected by professor Frederic Brewster Loomis. However, the only available information regarding its provenance is that given on the label: "Lance Creek", a county in east Wyoming. Loomis himself thought that it stemmed from the Lance Formation, dating from the Late Cretaceous Maastrichtian.

In 1963 the specimen was brought to the attention of John Stanton McIntosh, who in 1992, together with William Coombs and Dale Russell, decided to create a new genus and species for it. The type species is Dyslocosaurus polyonychius. The genus name is derived from Greek dys, "bad, "poor", and Latin locus, "place", a reference to the paucity of data regarding the type locality of the fossil. The specific name is derived from Greek polys, "many", and onyx, "claw". The describers interpreted the remains, consisting of some limb bones, as those of a diplodocid dinosaur. From this they concluded that it in fact dated from the Late Jurassic Period, like most diplodocids. The species would then be unique in having four, or perhaps five, claws on the foot, whereas other diplodocids have only three — hence the specific name. A species similar to Dyslocosaurus would have made the tracks of the ichnospecies Brontopodus birdi from the Early Cretaceous, that also features four claws.

In 1998 Paul Sereno and Jeffrey A. Wilson gave an alternative interpretation: the specimen would come from the Lance Formation after all but be a chimera: in this case a mix up of titanosaur limb bones and theropod phalanges.

In their taxonomic revision of Diplodocidae, Tschopp et alii in 2015 noted that a pedal phalanx included in AC 663 is apparently not from the same individual as the rest of AC 663 given differences in preservation and coloration among individual bones, raising doubts on whether Dyslocosaurus had more than three claws on the feet. Although fragmentary, Dyslocosaurus was recovered as a member of Dicraeosauridae, potentially making it the second record of a dicraeosaurid from North America (the other being Suuwassea).

Euhelopus

Euhelopus is a genus of titanosauriform sauropod dinosaur that lived between 129 and 113 million years ago during the Early Cretaceous in what is now Shandong Province in China. It was a large quadrupedal herbivore. Unlike most other sauropods, Euhelopus had longer forelegs than hind legs. This discovery was paleontologically significant because it represented the first dinosaur scientifically investigated from China: seen in 1913, rediscovered in 1922, and excavated in 1923. Unlike most sauropod specimens, it has a relatively complete skull.

Histriasaurus

Histriasaurus (HIS-tree-ah-SAWR-us) (meaning "Istria lizard") was a genus of dinosaur from the Early Cretaceous (Hauterivian to Barremian stages, around 130 million years ago). Its fossils, holotype WN V-6, were found near the town of Bale on the Istrian peninsula in Croatia, and described in 1998 by Dalla Vecchia. It was a diplodocoid sauropod, related to, but more primitive than, Rebbachisaurus. Phylogenetic analyses published in 2007 and 2011 placed Histriasaurus as the most basal member of Rebbachisauridae.The type species, H. boscarollii, was described by Dalla Vecchia in 1998. The specific name honours the discoverer of the site, Darío Boscarolli. Although some authors consider Histriasaurus a dubious taxon, more recent papers support the original classification.

Isisaurus

Isisaurus (named after the Indian Statistical Institute) is a genus of dinosaur from the Late Cretaceous Period. Isisaurus was a sauropod (specifically a titanosaur), which lived in what is now India.

Jeffrey Wilson

Jeffrey Wilson may refer to:

Jeffrey A. Wilson, professor of geological sciences

Jeffrey T. Wilson, chief executive officer of Imperial Petroleum

Neosauropoda

Neosauropoda is a clade within Dinosauria, coined in 1986 by Argentine paleontologist José Bonaparte and currently described as Saltasaurus loricatus, Diplodocus longus, and all animals directly descended from their most recent common ancestor. The group is composed of two subgroups: Diplodocoidea and Macronaria. Arising in the early Jurassic and persisting until the Cretaceous-Paleogene extinction event, Neosauropoda contains the majority of sauropod genera, including genera such as Apatosaurus, Brachiosaurus, and Diplodocus. It also includes giants such as Argentinosaurus, Patagotitan and Sauroposeidon, and its members remain the largest land animals ever to have lived.When Bonaparte first coined the term Neosauropoda in 1986, he described the clade as comprising “end-Jurassic” sauropods. While Neosauropoda does appear to have originated at the end of the Jurassic period, it also includes members through the end of the Cretaceous. Neosauropoda is currently delineated by specific shared, derived characteristics rather than the time period in which its members lived. The group was further refined by Upchurch, Sereno, and Wilson, who have identified thirteen synapomorphies shared among neosauropods. As Neosauropoda is a subgroup of Sauropoda, all members also display basic sauropod traits such as large size, long necks, and columnar legs.

Ornithischia

Ornithischia () is an extinct clade of mainly herbivorous dinosaurs characterized by a pelvic structure similar to that of birds. The name Ornithischia, or "bird-hipped", reflects this similarity and is derived from the Greek stem ornith- (ὀρνιθ-), meaning "of a bird", and ischion (ἴσχιον), plural ischia, meaning "hip joint". However, birds are only distantly related to this group as birds are theropod dinosaurs.Ornithischians with well known anatomical adaptations include the ceratopsians or "horn-faced" dinosaurs (e.g. Triceratops), armored dinosaurs (Thyreophora) such as stegosaurs and ankylosaurs, pachycephalosaurids and the ornithopods. There is strong evidence that certain groups of ornithischians lived in herds, often segregated by age group, with juveniles forming their own flocks separate from adults. Some were at least partially covered in filamentous (hair- or feather- like) pelts, and there is much debate over whether these filaments found in specimens of Tianyulong, Psittacosaurus, and Kulindadromeus may have been primitive feathers.

Pabwehshi

Pabwehshi (meaning "Pab [Formation] beast ["wehshi" in Urdu]") is an extinct genus of mesoeucrocodylian. It is based on GSP-UM 2000, a partial snout and corresponding lower jaw elements, with another snout assigned to it. These specimens were found in Maastrichtian-age Upper Cretaceous rocks of the Pab Formation in Balochistan, Pakistan, and represent the first diagnostic crocodyliform fossils from Cretaceous rocks of South Asia. Pabwehshi had serrated interlocking teeth in its snout that formed a "zig-zag" cutting edge. Pabwehshi was named in 2001 by Jeffrey A. Wilson and colleagues. The type species is P. pakistanensis, in reference to the nation where it was found. It was traditionally classified as a baurusuchid closely related to Cynodontosuchus and Baurusuchus. Larsson and Sues (2007) found close affinity between Pabwehshi and the Peirosauridae within Sebecia. Montefeltro et al. Pabwehshi has a sagittal torus on its maxillary palatal shelves – a character that is absent in baurusuchids – but they did not include Pabwehshi in their phylogenetic analysis.

Patagosaurus

Patagosaurus (meaning "Patagonia lizard") is an extinct genus of eusauropodan dinosaur from the Middle Jurassic of Patagonia, Argentina. It was first found in deposits of the Cañadón Asfalto Formation, which date to around 165 to 161 million years ago. Although originally twelve specimens were assigned to the taxon, at least one of them may belong to a different genus. Patagosaurus probably lived alongside genera as Piatnitzkysaurus, Condorraptor, and Volkheimeria.

Since Patagosaurus is known from many specimens, including at least one juvenile, its anatomy and growth are fairly well understood. Both ages exhibit the typical features of a sauropod, a long neck, small head, a long tail, and being quadrupedal. The juvenile exhibits features different from the adult in regions like the mandible, pectoral girdle, pelvis and hindlimb, although overall their anatomy is quite similar. The many known specimens help fill in gaps in the anatomy of the genus, such as the forelimb and skull. Parts of the skeleton, like the pectoral girdle, tibia, and pubis are more robust, while others, like the forelimb and ischium, are more gracile. The material of Patagosaurus is similar to closely related taxa like Cetiosaurus and Volkheimeria, more primitive genera such as Barapasaurus and Amygdalodon, and more derived sauropods like Diplodocus and Camarasaurus.

Paul Sereno

Paul Callistus Sereno (born October 11, 1957) is a professor of paleontology at the University of Chicago and a National Geographic "explorer-in-residence" who has discovered several new dinosaur species on several continents, including at sites in Inner Mongolia, Argentina, Morocco and Niger. One of his most widely publicized discoveries is that of a nearly complete specimen of Sarcosuchus imperator — popularly known as SuperCroc — at Gadoufaoua in the Tenere desert of Niger.

Rajasaurus

Rajasaurus is a genus of carnivorous abelisaurid theropod dinosaur from the Late Cretaceous of India, containing one species: Rajasaurus narmadensis. The bones were excavated from the Lameta Formation in the Gujarat state of Western India, probably inhabiting what is now the Narmada River Valley. It was formally described by palaeontologist Jeffrey A. Wilson and colleagues in 2003 based on a partial skeleton comprising the braincase, spine, hip bone, legs, and tail–a first for an Indian theropod. The dinosaur likely measured 6.6 metres (22 ft), and had a single horn on the forehead which was probably used for display and head-butting. Like other abelisaurids, Rajasaurus was probably an ambush predator.

India at this time was an island, due to the break-up of the supercontinent Gondwana, though it is possible animals still were able to migrate to and from nearby continents. The creation of the subfamily Majungasaurinae, and its inclusion of abelisaurids from India, Madagascar, and Europe–including Rajasaurus–further reiterates this. The Lameta Formation has yielded several other dinosaur species, including abelisaurids and titanosaurian sauropods, similar to other Gondwanan landmasses. The area during the Cretaceous was probably forested, and served as a nesting grounds for several creatures. Rajasaurus has become a tourist attraction for the state of Gujarat.

Rebbachisauridae

Rebbachisauridae is a family of sauropod dinosaurs known from fragmentary fossil remains from the Cretaceous of South America, Africa, North America, and Europe.

Saltasaurinae

Saltasaurinae is a subfamily of titanosaurian sauropods known from the late Cretaceous period of South America, India and Madagascar. They are considered to be the most derived of all sauropods.

Sauropoda

Sauropoda ( or ), or the sauropods (; sauro- + -pod, "lizard-footed"), are a clade of saurischian ("lizard-hipped") dinosaurs. They had very long necks, long tails, small heads (relative to the rest of their body), and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land. Well-known genera include Brachiosaurus, Diplodocus, Apatosaurus, Brontosaurus, and Mamenchisaurus.Sauropods first appeared in the late Triassic Period, where they somewhat resembled the closely related (and possibly ancestral) group "Prosauropoda". By the Late Jurassic (150 million years ago), sauropods had become widespread (especially the diplodocids and brachiosaurids). By the Late Cretaceous, those groups had mainly been replaced by the titanosaurs, which had a near-global distribution. However, as with all other non-avian dinosaurs alive at the time, the titanosaurs died out in the Cretaceous–Paleogene extinction event. Fossilised remains of sauropods have been found on every continent, including Antarctica.The name Sauropoda was coined by O.C. Marsh in 1878, and is derived from Greek, meaning "lizard foot". Sauropods are one of the most recognizable groups of dinosaurs, and have become a fixture in popular culture due to their impressive size.

Complete sauropod fossil finds are rare. Many species, especially the largest, are known only from isolated and disarticulated bones. Many near-complete specimens lack heads, tail tips and limbs.

Spoon theory

The spoon theory or spoon metaphor is a disability metaphor (for a combination of ego depletion, fatigue, and other factors), a neologism used to explain the reduced amount of mental and physical energy available for activities of living and productive tasks that may result from disability or chronic illness. Spoons are a visual representation used as a unit of measure in order to quantify how much energy a person has throughout a given day. Each activity requires a given number of spoons, which will only be replaced as the person "recharges" through rest. A person who runs out of spoons has no choice but to rest until their spoons are replenished.

This metaphor is used to describe the planning that many people have to do to conserve and ration their energy reserves to accomplish their activities of daily living. The planning and rationing of energy-consuming tasks has been described as being a major concern of those with chronic and fatigue-related diseases, illness, or conditions. The theory explains the difference between those who don't seem to have energy limits and those that do. The theory is used to facilitate discussions between those with limited energy reserves and those without. Because healthy people typically are not concerned with the energy expended during ordinary tasks such as bathing and getting dressed, the theory helps healthy people realize the amount of energy expended by chronically ill or disabled people to get through the day.Spoons are widely discussed within autoimmune, disability, mental and other chronic illness online communities, as an emic descriptor. The term spoonie is sometimes used to refer to a person with a chronic illness that can be explained with the spoon theory.

Vahiny

Vahiny is an extinct genus of titanosaur sauropod dinosaur known from the Late Cretaceous of the Maevarano Formation, northwestern Madagascar. It contains a single species, Vahiny depereti.

Zapalasaurus

Zapalasaurus is a genus of dinosaur described by Leonardo Salgado, Ismar de Souza Carvalho and Alberto C. It was named after the city of Zapala. The type species, Zapalasaurus bonapartei, was found in the La Amarga Formation of the Neuquén Basin, Neuquén Province, Argentina. It was a diplodocoid, a long-necked herbivore, and it lived during the Early Cretaceous. The authors conclude from examining the skeleton that "The record of Zapalasaurus bonapartei shows that, at least in the Neuquén Basin, basal diplodocoids were more diverse than previously thought." Zapalasaurus is assumed to have a long neck which would have been developed for feeding adaption, allowing its neck to swing in an arc like shape. This would allow Zapalasaurus to browse a wide variety of plants and greens without having to walk very far.

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