The first fossils of "Massospondylus" were described by paleontologist Sir Richard Owen in 1854. Originally, Owen did not recognize these finds as those of a dinosaur; instead he attributed them to "large, extinct, carnivorous reptiles" that were related to today's lizards, chameleons and iguanas. This material, a collection of 56 bones, was found in 1853 by the government surveyor Joseph Millard Orpen in the Upper Elliot Formation at Harrismith, South Africa and was donated to the Hunterian Museum at the Royal College of Surgeons in London. Among the remains were vertebrae from the neck, back, and tail; a shoulder blade; a humerus; a partial pelvis; a femur; a tibia; and bones of the hands and feet.
History of discovery
Massospondylus
Massospondylus | History of discovery
Joseph Millard Orpen Richard Owen Sir Richard Owen Joseph Millard Orpen
what is massospondylus?
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Genus of sauropodomorph dinosaur
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who discovered this species?
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This discovery therefore "sheds some light in the evolutionary pathways through which the peculiar adaptations of giant dinosaurs were attained", stated French paleontologist Eric Buffetaut.
Massospondylus | Reproduction
Massospondylus ( ; from Greek, (massōn, "longer") and (spondylos, "vertebra")) is a genus of sauropodomorph dinosaur from the Early Jurassic Period (Hettangian to Pliensbachian ages, ca. 200–183 million years ago). It was described by Sir Richard Owen in 1854 from remains discovered in South Africa, and is thus one of the first dinosaurs to have been named. Fossils have since been found at other locations in South Africa, Lesotho, and Zimbabwe. Material from Arizona's Kayenta Formation, India, and Argentina has been assigned to this genus at various times, but the Arizonan and Argentinian material are now assigned to other genera.
Massospondylus | Introduction
"Massospondylus" had also been reported from Argentina, but this has been reassessed as a closely related but distinct genus. The fossils included several partial skeletons and at least one skull, found in the Lower Jurassic Canon del Colorado Formation of San Juan, Argentina. This material was named "Adeopapposaurus" in 2009. A specimen from South Africa previously assigned to "Massospondylus", BP/1/4779, became the holotype of the new genus and species "Ngwevu intloko" in 2019.
Massospondylus | History of discovery
The first fossils of "Massospondylus" were described by paleontologist Sir Richard Owen in 1854. Originally, Owen did not recognize these finds as those of a dinosaur; instead he attributed them to "large, extinct, carnivorous reptiles" that were related to today's lizards, chameleons and iguanas. This material, a collection of 56 bones, was found in 1853 by the government surveyor Joseph Millard Orpen in the Upper Elliot Formation at Harrismith, South Africa and was donated to the Hunterian Museum at the Royal College of Surgeons in London. Among the remains were vertebrae from the neck, back, and tail; a shoulder blade; a humerus; a partial pelvis; a femur; a tibia; and bones of the hands and feet.
Massospondylus | History of discovery
All these bones were found disarticulated, making it difficult to determine if all material belongs to a single species or not. However, Owen was able to distinguish three different types of caudal vertebrae, which he attributed to three different genera: "Pachyspondylus", "Leptospondylus" and "Massospondylus". "Massospondylus" was separated from the other two genera on the basis of its much longer caudal vertebrae, which also led to the scientific name that has been derived from the Greek terms "masson"/μάσσων 'longer' and "spondylos"/σπόνδυλος 'vertebra', explained by Owen as "because the vertebrae are proportionally longer than those of the extinct Crocodile called "Macrospondylus"". However, later it was shown that the putative caudal vertebrae of "Massospondylus" were actually cervical vertebrae and that all the material probably belongs only to a single species.
Massospondylus | History of discovery
On May 10, 1941, the Hunterian Museum was demolished by a German bomb, destroying all the fossils; only casts remain. Because the plaster casts of the lost type specimen fossils were not adequate to accurately diagnose a genus and species under modern taxonomic practices and for research purposes, Yates and Barrett (2010) designated BP/1/4934, a skull and a largely complete postcranial skeleton in the Bernard Price Institute for Palaeontological Research, as the neotype specimen. "Massospondylus" remains have been found in the Upper Elliot Formation, the Clarens Formation, and the Bushveld Sandstone of South Africa and Lesotho, as well as the Forest Sandstone of Zimbabwe.
Massospondylus | History of discovery
The type species is "M. carinatus"; seven other species have been named during the past 150 years, but only "M. kaalae" among these is still considered valid. Early sauropodomorphs systematics have undergone numerous revisions during the last several years, and many scientists disagree where exactly "Massospondylus" lies on the dinosaur evolutionary tree. The family name Massospondylidae was once coined for the genus, but because knowledge of early sauropodomorph relationships is in a state of flux, it is unclear which other dinosaurs—if any—belong in a natural grouping of massospondylids; several 2007 papers support the family's validity. Although "Massospondylus" was long depicted as quadrupedal, a 2007 study found it to be bipedal.
Massospondylus | Introduction
"Massospondylus" was a mid-size sauropodomorph, around in length and weighed approximately 1000 kilograms (2200 lb), although a few sources have estimated its length at up to . It was a typical early sauropodomorph, with a slender body, a long neck and a proportionally very small head. The vertebral column was composed of nine cervical (neck) vertebrae, 13 dorsal (back) vertebrae, three sacral (hip) vertebrae, and at least 40 caudal (tail) vertebrae. The pubis faced forward, as with most saurischians. It had a slighter build than that of "Plateosaurus", an otherwise similar dinosaur. The neck was proportionally longer than in most other plateosaurids, with the foremost cervicals being four times the length of their width.
Massospondylus | Description
Several genera have been previously synonymized with "Massospondylus". These include the above-mentioned "Leptospondylus" and "Pachyspondylus", as well as "Aristosaurus", "Dromicosaurus", "Gryponyx taylori" and "Hortalotarsus", which are dubious names of little scientific value. Together with "Massospondylus carinatus", Owen named "Leptospondylus capensis" and "Pachyspondylus orpenii" for vertebrae from the same unit and location. "Aristosaurus erectus" was named by E.C.N. van Hoepen in 1920 based on a nearly complete skeleton, and Hoepen also named "Dromicosaurus gracilis", which consisted of a partial skeleton. "Gryponyx taylori" was named by Sidney H. Haughton in 1924. It consists of hip bones. All of the above fossils come from the Hettangian or Sinemurian faunal stages of South Africa, where "Massospondylus" has been found.
Massospondylus | Dubious names
Teeth closer to the front of the snout had round cross-sections and tapered to points, unlike the back teeth, which were spatulate and had oval cross-sections. As with other early sauropodomorphs, it has been proposed that "Massospondylus" had cheeks. This theory was proposed because there are a few large holes for blood vessels on the surfaces of the jaw bones, unlike the numerous small holes present on the jaws of cheekless reptiles. The cheeks would have prevented food from spilling out when "Massospondylus" ate. Crompton and Attridge (1986) described skulls of "Massospondylus" as possessing pronounced overbites and suggested the presence of a horny beak on the tip of the lower jaw to make up the difference in length and account for tooth wear on the teeth at the tip of the snout.
Massospondylus | Cranial anatomy
However, newer finds revealed a diverse contemporary sauropodomorph fauna with six additional species, including "Ignavusaurus", "Arcusaurus" and two unnamed taxa as well as two unnamed sauropods. It is not clear which carnivores may have preyed on "Massospondylus". Most of the theropods that have been discovered in rocks of Early Jurassic age in southern Africa, such as "Coelophysis", were smaller than mid-sized sauropodomorphs like "Massospondylus". These smaller predators have been postulated as using fast slashing attacks to wear down sauropodomorphs, which could have defended themselves with their large hand and foot claws. The 6-metre-(20 ft-) long carnivorous theropod "Dracovenator" lived during the same period (Hettangian to Sinemurian stages) as "Massospondylus" and has also been found in the Elliot Formation of South Africa.
Massospondylus | Paleoecology
Massospondylidae is a family of early massopod dinosaurs that existed in Asia, Africa, North America, 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.
Massospondylidae | Introduction
It was probably a plant eater (herbivore), although it is speculated that the early sauropodomorphs may have been omnivorous. This animal, which was long, had a long neck and tail, with a small head and slender body. On each of its forefeet, it bore a sharp thumb claw that was used in defense or feeding. Recent studies indicate that "Massospondylus" grew steadily throughout its lifespan, possessed air sacs similar to those of birds, and may have cared for its young.
Massospondylus | Introduction
Bonnan and Yates (2007) considered "Camelotia", "Blikanasaurus" and "Melanorosaurus" possible sauropods. Yates (2007) placed "Antetonitrus", "Melanorosaurus", and "Blikanasaurus" as basal sauropods and declined to use the term Prosauropoda, as he considered it synonymous with Plateosauridae. However, he did not rule out the possibility that a small group of prosauropods consisting of "Plateosaurus", "Riojasaurus", "Massospondylus" and their closest kin were monophyletic. "Massospondylus" is the type genus of the proposed family Massospondylidae, to which it gives its name. The Massospondylidae may also include "Yunnanosaurus", although Lu "et al." (2007) placed "Yunnanosaurus" in its own family. Yates (2007) considered "Massospondylus", "Coloradisaurus", and "Lufengosaurus" massospondylids, with "Yunnanosaurus" in Anchisauria.
Massospondylus | Classification
As with all dinosaurs, much of the biology of "Massospondylus", including its behavior, coloration, and physiology, remains unknown. However, recent studies have allowed for informed speculation on subjects such as growth patterns, diet, posture, reproduction, and respiration. A 2007 study suggested that "Massospondylus" may have used its short arms for defense against predators ("defensive swats"), in intraspecies combat, or in feeding, although its arms were too short to reach its mouth. Scientists speculate that "Massospondylus" could have used its large pollex (thumb) claw in combat, to strip plant material from trees, digging, or for grooming.
Massospondylus | Paleobiology
In 1905 and 1906 Baron Franz Nopcsa reassigned the skeleton to the species, "Streptospondylus cuvieri", which had been first described by Sir Richard Owen in 1842, based on a now lost vertebra from the Bathonian stage of the Jurassic period. The reason for this assignment was that the type species "Streptospondylus altdorfensis" from France, was a clearly related form, and Nopcsa decided to subsume all British material of this nature under a single "Streptospondylus" species, for which then the name "S. cuvieri" could not be avoided. The assignment of a rather complete find to a species based on very poor remains was troublesome.
Eustreptospondylus | Discovery and naming
In 1976, a clutch of seven 190-million-year-old "Massospondylus" eggs was found in Golden Gate Highlands National Park in South Africa by James Kitching, who identified them as most likely belonging to "Massospondylus". It was nearly 30 years before extraction was started on the fossils of the 15-centimetre- (6 in-) long embryos. They remain the oldest dinosaur embryos ever found. By early 2012, at least 10 egg clutches from at least four fossiliferous horizons had been found, with up to 34 eggs per clutch. This indicates that this nesting site may have been used repeatedly (site fidelity), by groups of animals (colonial nesting); in both cases, these represent the oldest evidence of this behaviour.
Massospondylus | Reproduction
The neck was short, contrasting to the very long neck in the adults. Girdle bones and caudals were relatively tiny. The forelimbs were of equal length to the hindlimbs, indicating that newly hatched "Massospondylus" were quadrupedal, unlike the bipedal adults. The discovery of hatching footprints with manus impressions confirmed their quadrupedality. These impressions show that the hand was not pronated, with palm faces facing each other and the thumb facing forwards. The unpronated manus and the big head indicate that an effective locomotion was not possible for newly hatched "Massospondylus". Notably, the near-hatchings had no teeth, suggesting they had no way of feeding themselves.
Massospondylus | Reproduction
The faunas and floras of the Early Jurassic were similar worldwide, with conifers adapted for hot weather becoming the common plants; basal sauropodomorphs and theropods were the main constituents of a worldwide dinosaur fauna. The environment of early Jurassic southern Africa has been described as a desert. African "Massospondylus" was a contemporary of temnospondyli; turtles; a sphenodontia; rauisuchids; early crocodylomorphs; tritylodontid and trithelodontid therapsids; morganucodontid mammals; and dinosaurs including the small theropod "Coelophysis rhodesiensis" and several genera of early ornithischians, such as "Lesothosaurus" and the heterodontosaurids "Abrictosaurus", "Heterodontosaurus", "Lycorhinus" and "Pegomastax". Until recently, "Massospondylus" was regarded as the only known sauropodomorph from the Upper Elliot Formation.
Massospondylus | Paleoecology
Marmarospondylus ("marble [reference to the Forest Marble Formation] vertebra") is a dubious genus of sauropod dinosaur from Middle Jurassic deposits in the English Midlands. The type species, "Marmarospondylus robustus", was described by Richard Owen as a species of the Late Jurassic genus "Bothriospondylus" in 1875. The holotype, NHMUK R.22428, a dorsal, was found in the Bathonian-age Forest Marble Formation at Bradford-on-Avon, Wiltshire. Owen himself in an addendum to the same publication coined "Marmarospondylus" for "B. robustus", presumably due to its being older than "B. suffosus". Recent publications have treated "Marmarospondylus" as a dubious member of Macronaria.
Marmarospondylus | Introduction
Smith and Pol (2007) also found a Massospondylidae in their phylogenetic analysis, including "Massospondylus", "Coloradisaurus", and "Lufengosaurus", as well as their new genus, "Glacialisaurus". "Adeopapposaurus", based on the fossils once thought to belong to a South American form of "Massospondylus", was also classified as a massospondylid, as was "Leyesaurus", another South American genus that was named in 2011. "Pradhania" was originally regarded as a more basal sauropodomorph but new cladistic analysis performed by Novas "et al.", 2011 suggests that "Pradhania" is a massospondylid. "Pradhania" presents two shared traits of the Massospondylidae recovered in their phylogenetic analysis, and the fossils of "Pradhania" were discovered from the same region and basin in India as "M.
Massospondylus | Classification
Basal sauropodomorph systematics continue to undergo revision, and many genera once considered classic "prosauropods" have recently been removed from the group in phylogenetic nomenclature, on the grounds that their inclusion would not constitute a clade (a natural grouping containing all descendants of a single common ancestor). Yates and Kitching (2003) published a clade consisting of "Riojasaurus", "Plateosaurus", "Coloradisaurus", "Massospondylus", and "Lufengosaurus". Galton and Upchurch (2004) included "Ammosaurus", "Anchisaurus", "Azendohsaurus", "Camelotia", "Coloradisaurus", "Euskelosaurus", "Jingshanosaurus", "Lessemsaurus", "Lufengosaurus", "Massospondylus", "Melanorosaurus", "Mussaurus", "Plateosaurus", "Riojasaurus", "Ruehleia", "Saturnalia", "Sellosaurus", "Thecodontosaurus", "Yimenosaurus" and "Yunnanosaurus" in a monophyletic Prosauropoda. Wilson (2005) considered "Massospondylus", "Jingshanosaurus", "Plateosaurus", and "Lufengosaurus" a natural group, with "Blikanasaurus" and "Antetonitrus" possible sauropods.
Massospondylus | Classification
In 2000, Olshevsky renamed "Troodon isfarensis" Nessov 1995 into "Saurornithoides isfarensis". In 2007, this was shown to have been a hadrosaurid fossil.
Saurornithoides | History of discovery
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".
Massospondylidae | Introduction
"Streptospondylus" was one of the first dinosaurs collected and was the first described, though not the first dinosaur named. It was not recognised as a theropod dinosaur until 2001. In 1778, abbey Charles Bacheley (1716-1795), a Norman naturalist, reported the presence of fossil bones in the Callovo-Oxfordian formations, either the Marnes de Dives or the overlying Marnes de Villers, probably the former, exposed at the foot of the cliffs between Villers-sur-Mer and Houlgate. These fossil materials contained theropod vertebrae and marine crocodilian remains. After the death of Bacheley, his fossil cabinet was acquired by the "Ecole centrale de Rouen". Louis-Benoît Guersent (1777–1848), professor of natural history in this school, drew the attention of Georges Cuvier to this remarkable fossil bones.
Streptospondylus | Discovery and naming
With the agreement of the prefect of Seine-Inférieure, count Jacques Claude Beugnot, Guersent sent the collection to the Muséum National d'Histoire Naturelle in Paris. In 1800, these fossils were briefly mentioned by Georges Cuvier who misspelled the name of their former owner as Bachelet. In 1808, Cuvier scientifically described the theropod vertebrae as the first dinosaur remains ever. However, he considered them to be crocodilian and associated them with fossils of the Teleosauridae and the Metriorhynchidae. In 1822, Cuvier by the work of Henry De La Bèche became aware that these finds were very disparate, stemming from different periods. He abstained from naming them but in 1824 concluded that there were two main types.
Streptospondylus | Discovery and naming
He then formally described the remains in the same year, finding them to be a new genus and species, which he named "Saurornithoides mongoliensis". The generic name was chosen because of the bird-like bones of the taxon, which was thought to represent a megalosaurian, translating as "saurian with bird-like rostrum". "Saurornithoides" was noted to resemble "Velociraptor", although more sluggish according to Osborn. The holotype specimen is AMNH 6516. This specimen was the first troodontid skeleton found, though at the time the connection with "Troodon", then known only from its teeth, was not realised. In 1964, another specimen was described from the Late Cretaceous of Mongolia.
Saurornithoides | History of discovery
Eustreptospondylus ( ; meaning "true "Streptospondylus"") is a genus of megalosaurid theropod dinosaur, from the Oxfordian stage of the Late Jurassic period (some time between 163 and 154 million years ago) in southern England, at a time when Europe was a series of scattered islands (due to tectonic movement at the time which raised the sea-bed and flooded the lowland).
Eustreptospondylus | Introduction
These remains consist of at least 80 partial skeletons and four skulls, representing both juveniles and adults. The report of "Massospondylus" from Arizona's Kayenta Formation is based on a skull described in 1985. The skull of the Kayenta specimen from Arizona is 25% larger than the largest skull from any African specimen. The Kayenta specimen possesses four teeth in the premaxilla and sixteen in the maxilla. Uniquely among dinosaurs, it also had tiny, one-millimetre-(0.04 in-) long palatal teeth. A 2004 restudy of African "Massospondylus" skulls, however, indicated that the Kayenta specimen did not pertain to "Massospondylus". This Kayenta skull and associated postcranial elements, identified collectively as MCZ 8893, was referred to the new genus "Sarahsaurus" in 2010.
Massospondylus | History of discovery
The present individuals probably represented juveniles as indicated by small size and open bone sutures. From detailed features the describers concluded these were not juveniles of either "Aardonyx" or "Massospondylus".
Arcusaurus | Discovery
Although its mass suggests a quadrupedal nature, "Massospondylus" would have been restricted to its hind legs for locomotion. Since the discovery of rudimentary and nonfunctional clavicles in ceratopsians, it was assumed that these shoulder bones were reduced in all dinosaurs that did not have true furculae. Robert Bakker (1987) suggested that this would have allowed the shoulder blades to swing with the forelimbs in quadrupedal dinosaurs, increasing their functional forelimb length. This would have reduced the discrepancy of length between fore- and hindlimbs in a quadrupedal "Massospondylus". However, a recent discovery shows that "Massospondylus" possessed well-developed clavicles that were joined in a furcula-like arrangement, acting like a clasp between the right and left shoulder blades and prohibiting any rotation of these bones.
Massospondylus | Gait and range of motion
The skeleton was wall-mounted in bas relief, with the tail curved upwards, the neck straightened, and the left leg moved up for visibility, but the rest of the skeleton was kept in its burial position. As the skull was crushed, it was reconstructed based on the back of the skull of the first specimen and the front of the second. The pelvis was reconstructed after that of "Allosaurus", and the feet were also reconstructed. At the time, it was one of the best-preserved skeletons of a theropod dinosaur, though incomplete. In 1954, the paleontologist Samuel P. Welles, who was part of the group who excavated the skeletons, preliminarily described and named this dinosaur as a new species in the existing genus "Megalosaurus", "M.
Dilophosaurus | History of discovery
Yates assigned the Massopoda to Plateosauria. Within the clade, he assigned the families Massospondylidae (which includes the relatively well-known dinosaur "Massospondylus") and Riojasauridae (which includes "Riojasaurus") as well as the Sauropoda. The following is a simplified cladogram from an analysis presented by Blair McPhee and colleagues in 2014:
Massopoda | Classification
Early sauropodomorphs such as "Massospondylus" may have been herbivorous or omnivorous. As recently as the 1980s, paleontologists debated the possibility of carnivory in the "prosauropods". However, the hypothesis of carnivorous "prosauropods" has been discredited, and all recent studies favor a herbivorous or omnivorous lifestyle for these animals. Galton and Upchurch (2004) found that cranial characteristics (such as jaw articulation) of most basal sauropodomorphs are closer to those of herbivorous reptiles than those of carnivorous ones, and the shape of the tooth crown is similar to those of modern herbivorous or omnivorous iguanas. The maximum width of the crown was greater than that of the root, resulting in a cutting edge similar to those of extant herbivorous or omnivorous reptiles.
Massospondylus | Diet
"Ignavusaurus" is a basal sauropodomorph, a member of the long-necked, herbivorous, saurischian dinosaurs. Although originally recovered as more primitive than Plateosauria by Knoll (2010), Yates et al. (2011) noted that some characters used to place "Ignavusaurus" outside Massopoda are reflective of juvenile status and instead are more similar to juvenile "Massospondylus", considering "Ignavusaurus" probably synonymous with "Massospondylus". Meanwhile, a cladistic analysis presented by Apaldetti et al. (2011) found "Ignavusaurus" to be a valid genus which is most closely related to "Sarahsaurus" within Massopoda, somewhat agreeing with Yates et al. that "Ignavusaurus" is not as primitive as originally thought. A cladistic analysis conducted by Chapelle and Choiniere (2018) in their paper updating knowledge of the skull of "Massospondylus" recovered "Ignavusaurus" along with "Sarahsaurus" in Massospondylidae, as did the cladistic analysis of Chapelle et al.
Ignavusaurus | Classification
In 2003, Adam Yates named the new species "Thecodontosaurus caducus" for a skull and a skull, a partial jawbone, and vertebrae of the cervix, an incomplete right pelvic bone, and partial forelimbs of an immature sauropodomorph. This material had been known in the scientific literature since 1984, and had been used to represent the genus "Thecodontosaurus". However, changed understanding of the relationships and characteristics of basal sauropodomorphs (also known as prosauropods) has led Peter Galton, Yates, and D. Kermack to give "T. caducus" its own genus. The genus was named after the Pant-y-ffynnon quarry where it was discovered. "Pantydraco" takes its name from the "pant" of Pant-y-ffynnon quarry, meaning a dry valley and "draco" (a dragon or mythical dragon-like creature in Latin).
Pantydraco | Discovery and naming
The Massopoda is a clade of sauropodomorph dinosaurs which lived during the Late Triassic to the Late Cretaceous periods. It was named by paleontologist Adam M. Yates of the University of the Witwatersrand in 2007. Massopoda is a stem-based taxon, defined as all animals more closely related to "Saltasaurus loricatus" than to "Plateosaurus engelhardti". The name Massopoda, ; , is also contraction of Massospondylidae and Sauropoda, two disparate taxa in the clade.
Massopoda | Introduction
The type species, "Hortalotarsus skirtopodus" was named by Harry Seeley in 1894. According to Broom (1911), "Originally most of the skeleton was in the rock, and it was regarded by the farmers as the skeleton of a Bushman, but it is said to have been destroyed through fear that a Bushman skeleton in the rock might tend to weaken the religious belief of the rising generation." Seeley however, states that most of the skeleton was lost by a failed attempt to free it from the rock by using gunpowder. Some partial leg bones were salvaged. "Hortalotarsus" was subsequently regarded as either a synonym of "Massospondylus" or a valid genus belonging to Anchisauridae.
Hortalotarsus | Discovery and naming
Based on the lack of teeth and the ineffective locomotion, scientists speculate that postnatal care might have been necessary. This is further supported by evidence that the hatchings remained at the nest sites until they had doubled in size. Newly hatched juveniles are known from a second sauropodomorph, "Mussaurus"; these remains resemble those of the embryonic "Massospondylus", suggesting that quadrupedality was present in newly hatched "Mussaurus" and presumably other basal sauropodomorphs as well. The quadrupedality of the hatchings suggests that the quadrupedal posture of later sauropods may have evolved from retention of juvenile characteristics in adult animals, an evolutionary phenomenon known as pedomorphosis.
Massospondylus | Reproduction
Massospondylidae, which was first named by Huene in 1914, is a stem-based taxon. It was defined by Sereno as all animals more closely related to "Massospondylus carinatus" than to "Plateosaurus engelhardti" and "Saltasaurus loricatus". The following simplified cladogram is based on an analysis presented by Chappel and colleagues in 2019. Below is a simplified cladogram after Müller, 2019.
Massospondylidae | Phylogeny
"M. harriesi" is known from a well-preserved forelimb and parts of a hindlimb. "M. schwarzi" is known from an incomplete hind limb and sacrum. "M. hislopi" and "M. rawesi" were named from fossils found in India. "M. hislopi" is based on vertebrae from the Upper Triassic Maleri Formation of Andhra Pradesh, whereas "M. rawesi" is based on a tooth from the Upper Cretaceous Takli Formation of Maharashtra. "M. hislopi" was tentatively retained as an indeterminate sauropodomorph in the latest review, but "M. rawesi" may be a theropod or nondinosaur. "M. huenei" is a combination derived by Cooper for "Lufengosaurus huenei", as he considered "Lufengosaurus" and "Massospondylus" to be synonyms.
Massospondylus | Species
A 2005 study indicated that "Massospondylus"' sister taxon, "Plateosaurus", exhibited growth patterns affected by environmental factors. The study indicated that, when food was plentiful or when the climate was favorable, "Plateosaurus" exhibited accelerated growth. This pattern of growth is called "developmental plasticity". It is unseen in other dinosaurs, including "Massospondylus", despite the close relationship between the two. The study indicated that "Massospondylus" grew along a specific growth trajectory, with little variation in the growth rate and ultimate size of an individual. Another study of age determination indicated that "Massospondylus" grew at a maximum rate of 34.6 kg (76.3 lb) per year and was still growing at around 15 years of age.
Massospondylus | Growth
Others however, including BMNH R10390, found near Sandown Bay on the Isle of Wight, and BMNH R2133 and R2115, found near Hastings, actually belonged to some iguanodont. Noticing Owen's mistake in assigning iguanodont bones to "Cetiosaurus", comparative anatomist Alexander Melville renamed the sauropod bones "Cetiosaurus conybeari" in 1849. In 1850, Gideon Mantell decided that "C. conybeari" was so different from "Cetiosaurus" that it needed a new genus, so he reclassified it under the new name "Pelorosaurus conybeari". Mantell had originally, in November 1849, intended to use the name "Colossosaurus", but upon discovering that "kolossos" was Greek for "statue" and not "giant", he changed his mind.
Pelorosaurus | History
Massaliasuchus is an extinct genus of allodaposuchid crocodylian that is known from fossils found in Santonian–Campanian-age Upper Cretaceous rocks of southeastern France.
Massaliasuchus | Introduction
To complete the mount, sauropod feet that were discovered at the same quarry and a tail fashioned to appear as Marsh believed it shouldbut which had too few vertebraewere added. In addition, a sculpted model of what the museum thought the skull of this massive creature might look like was made. This was not a delicate skull like that of "Diplodocus"which was later found to be more accuratebut was based on "the biggest, thickest, strongest skull bones, lower jaws and tooth crowns from three different quarries". These skulls were likely those of "Camarasaurus", the only other sauropod for which good skull material was known at the time.
Apatosaurus | Discovery and species
Among known fossil specimens, approximately 66% are known from only cranial remains. "Acrotholus"' discovery further implicates the diversity of small bodied dinosaurs which may not have survived the fossil record, suggesting a much more complex ecology in the late Mesozoic era. A similar conclusion have been made with Asian species of pachycephalosaurs, with their ontogeny under debate due to their flat domed shapes.
Acrotholus | History of discovery
This was compounded by German palaeontologist Friedrich von Huene, who sometime referred to the specimen as "Streptospondylus cuvieri" and at other times considered it a species of "Megalosaurus": "Megalosaurus cuvieri". In 1964, Alick Donald Walker clarified matters by erecting a separate genus and species for the Oxford specimen: "Eustreptospondylus oxoniensis". The genus name "Eustreptospondylus", was intended to mean "true "Streptospondylus"". "Streptospondylus" means "turned vertebra", and is derived from the Greek words "streptos" (στρεπτος) meaning "reversed" and "spondylus" (σπονδυλος), a reference to the fact that its dorsal vertebrae were opisthocoelous, in contrast to the typical procoelous vertebrae of crocodiles. The specific name "oxoniensis", refers to its provenance from Oxford.
Eustreptospondylus | Discovery and naming
Boynton. The discovery has been called "the most prized specimen" in Mount Holyoke College's geological museum. It's also been regarded as the last major find in the "Connecticut Valley 'bone rush'". That December, Talbot gave a presentation to the Paleontological Society about her dinosaur discovery in South Hadley. She interpreted the skeleton as belonging to an herbivore. The next year Mignon Talbot collaborated with Richard Swann Lull collaborated on a description for the recently discovered dinosaur at South Hadley. They correct Talbot's previous misidentification of the specimen as an herbivore and reclassify it as a theropod. They named it Podokesaurus holyokensis.
Paleontology in Massachusetts | Scientific research
The type and referred specimens of "Plesiosuchus" were discovered by John Clavell Mansel-Pleydell in the 1860s alongside the remains of several other large-bodied marine reptiles along the coast of Dorset. Mansel-Pleydell gave these remains to the British Museum (now in the Natural History Museum) in 1866. Part of the holotype of "P. manselii" (NHMUK PV OR40103a) was first described by John Hulke in 1869. He referred it to "Steneosaurus rostro-minor" Geoffroy (1825), alongside "Dakosaurus maximus" and other specimens. Initially, the skull (NHMUK PV OR40103) was believed to be pliosaurian; it was the preparator Mr Davies that suggested a crocodylian nature for the skull.
Plesiosuchus | Discovery
Thecospondylus (THEEK-o-SPON-di-lus, "sheath vertebra") is a dubious genus of dinosaur from the Early Cretaceous of England. Dr. A.C. Horner, an amateur geologist living at Tonbridge, in the nineteenth century acquired a fossil found in the quarry of Southborough. He sent it to paleontologist Harry Govier Seeley who in 1882 described and named it as the type species "Thecospondylus horneri". The genus name is derived from Greek "theke" meaning 'sheath' and "spondylos" meaning 'vertebra', a reference to the "extremely thin" bone forming the vertebrae. The specific name honours Horner. The holotype, BMNH R.291, was found in a layer of the Hastings Sand, sandstone dating from the Valanginian - Hauterivian.
Thecospondylus | Introduction
Streptospondylus (meaning "reversed vertebra") is a genus of tetanuran theropod dinosaur known from the Late Jurassic period of France, 161 million years ago. It was a medium-sized predator with an estimated length of 6 meters (19.5 ft) and a weight of 500 kg (1,100lbs).
Streptospondylus | Introduction
The genus was limited to the bonebed remains; for example, the partial skeleton from Wise County known as "Pleurocoelus" sp. (SMU 61732) is not referred to "Paluxysaurus"; instead that specimen is the holotype of "Astrophocaudia slaughteri" D'Emic 2012, another somphospondylan sauropod. There are differences in the remains of "P." sp. and "Paluxysaurus", but they cannot be distinguished with confidence. In 2012, re-analysis of these specimens in light of additional "Sauroposeidon" remains led paleontologists D'Emic and Foreman to conclude that "Paluxysaurus" was the same animal as "Sauroposeidon", and thus a junior synonym of "S. proteles".
Sauroposeidon | Discovery
The type species is "D. grallator", meaning "one who walks on stilts" in Greek, in reference to its long slender limbs. It was named and described by Hans-Dieter Sues and colleagues in 2003. When the students excavated the blocks, the fossils were tentatively identified remains as those of a large, unnamed new genus of popsaurid rauisuchian. Upon preparation, however, it was discovered that there was the skeleton of a smaller archosaur under its pelvis, and the bones of several different animals as gut contents that remained in place in the rauisuchian fossil: these included bones and scutes of the aetosaur "Stegomus", some with tooth marks; bones from the snout, arm, and shoulder of the traversodont cynodont "Plinthogomphodon"; phalanx bones of a dicynodont; and a bone fragment from a possible temnospondyl.
Dromicosuchus | Discovery
Owen thought that the name "Mastodonsaurus" "ought not to be retained, because it recalls unavoidably the idea of the mammalian genus "Mastodon", or else a mammilloid form of the tooth... and because the second element of the word, "saurus", indicates a false affinity, the remains belonging, not to the Saurian, but to the Batrachian order of Reptiles." Owen recognized that the animal was not a "saurian" reptile, yet he also referred Jaeger's "Phytosaurus" to the genus. Although the two genera have similarly sized conical teeth, "Phytosaurus" was later found to be a crocodile-like reptile. Additional material, including skulls, firmly placed "Labyrinthodon" as an amphibian.
Temnospondyli | History of study
Unfortunately, mixed in with the "Scelidosaurus" fossils had been the partial remains of a theropod dinosaur and the femur and tibia thus belonged to such a carnivore; this was not discovered until 1968 by Bernard Newman. The same year, B. H. Newman suggested to have Lydekker's selection of the knee joint as the lectotype officially rescinded by the International Commission on Zoological Nomenclature, as the joint was in his opinion from a species related to "Megalosaurus". Eventually, after Newman had already died, Alan Jack Charig actually filed a request in 1992. In 1994 the ICZN reacted positively, in Opinion 1788 deciding that the skull and skeleton, specimen BMNH R.1111, would be the neotype of "Scelidosaurus".
Scelidosaurus | History of discovery
Other dinosaurs found in this formation include the theropod "Megapnosaurus", the sauropodomorph "Massospondylus", as well as other heterodontosaurids like "Heterodontosaurus" and "Lycorhinus". Remains of terrestrial crocodylomorphs, cynodonts and early mammals are also abundant.
Abrictosaurus | Introduction
Under the rules of zoological nomenclature, these names are junior synonyms. They were named after "Massospondylus" was described in a scientific paper; the name "Massospondylus" thus takes priority. "Ignavusaurus", known from a young specimen, was considered by Yates et al. (2011) to be a probable synonym of "Massospondylus". Cladistic analyses by Chapelle & Choiniere (2018) and Chapelle et al. (2019) agreed with Yates et al. (2011) in demonstrating the massospondylid nature of "Ignavusaurus", but nevertheless recovered it as a distinct taxon of massospondylid.
Massospondylus | Dubious names
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. Recent cladistic analyses by Yates (2007), Yates "et al." (2010, 2011) and Novas "et al." (2011) found the same results. The discovery of "Glacialisaurus" is important to the study of the early distribution of sauropod dinosaurs.
Glacialisaurus | Phylogeny
Today, they are seen as a separate genus "Becklespinax", but Owen referred them to "Megalosaurus". The models at the exhibition created a general public awareness for the first time, at least in England, that ancient reptiles had existed. The presumption that carnivorous dinosaurs, like "Megalosaurus", were quadrupeds was first challenged by the find of "Compsognathus" in 1859. That, however, was a very small animal, the significance of which for gigantic forms could be denied. In 1870, near Oxford, the type specimen of "Eustreptospondylus" was discovered - the first reasonably intact skeleton of a large theropod. It was clearly bipedal. Shortly afterwards, John Phillips created the first public display of a theropod skeleton in Oxford, arranging the known "Megalosaurus" bones, held by recesses in cardboard sheets, in a more or less natural position.
Megalosaurus | Early reconstructions
All elements of the skeleton are now known. The finds by Sole differ from the neotype in details of the armour and might represent a separate taxon or reflect sexual dimorphism. In 2019, Norman denied this.
Scelidosaurus | History of discovery
Sauropodomorph remains were first documented in North America in 1818, when some bones were uncovered by Mr. Solomon Ellsworth, Jr. while excavating a well with gunpowder in East Windsor, Connecticut. At the time of their discovery it was thought that the bones might be those of a human, but the presence of tail vertebrae falsified that idea. They are now recognized as those of an indeterminate sauropodomorph, possibly more closely related to the plateosaurian prosauropods. In 1855, the original type specimen of "Anchisaurus polyzelus", AM 41/109, which is housed at the Amherst College Museum of Natural History, was found by William Smith in Springfield, Massachusetts during blasting a well for the waterhouse at the Springfield Armory.
Anchisaurus | Discovery and naming
"Thecocoelurus" is known only from half of a single cervical vertebra, discovered by the Rev. William Darwin Fox on the Isle of Wight during the 19th century. After his death the "Fox Collection" was acquired by the British Museum of Natural History. William Davies was the first to notice the specimen and assumed a close affinity with "Coelurus". It was described by Harry Govier Seeley in 1888. Seeley named the fossil "Thecospondylus daviesi", referring it to a genus he had named earlier for the incomplete cast of a sacrum. However, in 1901 Baron Franz Nopcsa renamed it "Coelurus daviesi". In 1923 Friedrich von Huene decided that it should be removed from either "Thecospondylus" or "Coelurus" and given its own genus, "Thecocoelurus".
Thecocoelurus | Discovery and naming
In the most recent review, it was considered to be a dubious ceratosaurian. ""Massospondylus"" "rawesi", another tooth taxon, but from probable Upper Triassic rocks, is sometimes given as a second species of this genus, but it may not be dinosaurian, and could be substantially older.
Orthogoniosaurus | Introduction
Somphospondyli is an extinct clade of titanosauriform sauropods that lived from the Late Jurassic until the end of the Late Cretaceous. The remains of somphospondylans have been discovered in all seven continents.
Somphospondyli | Introduction
Following excavation and preparation of the majority of the fossils from the site, its sauropod species was given the name "Paluxysaurus jonesi". The name "Paluxysaurus" was based on the specimen FWMSH 93B-10-18, a partial skull including an associated left maxilla, nasal, and teeth. Other bones from the quarry included a partial neck of seven vertebrae, thirteen vertebrae from the back and 30 from the tail, and examples of all limb and girdle bones except some hand and foot bones. It was distinguished from all other sauropods by vertebral details, and has various morphological differences in other bones compared to other sauropods of the Early Cretaceous of North America.
Sauroposeidon | Discovery
The other finds, made at different localities, include several skeletons of the tyrannosaurid "Tarbosaurus" as well as the type specimens of the giant ornithomimosaur "Deinocheirus", the sauropod "Nemegtosaurus", and the pachycephalosaur "Homalocephale". On the fifth day of fieldwork, Ryszard Gradziński, the geologist of the expedition, found a concretion of well-preserved bones which promised to belong to a fairly complete skeleton. Excavation starting the next day revealed a nearly complete skeleton lacking only the head and neck. Until today, this specimen remains by far the most complete finding of this dinosaur. The transport of the specimen out of rough terrain caused major technical problems.
Opisthocoelicaudia | Discovery and specimens
1830 Isaac Hays described a new species of fossil fish from the Cretaceous of New Jersey that he named "Saurodon leanus". The new find by Hays was similar enough to the purported marine reptile "Saurocephalus lanciformis" discovered in Iowa during the Lewis and Clark expedition that he realized "Saurocephalus" had been misidentified and was actually a fish. Another significant event occurred around 1838, when workers excavating marl for fertilizer on land owned by John E. Hopkins uncovered some Late Cretaceous bones. The remains were mostly vertebrae but also included a possible shoulder blade. Hopkins wasn't especially interested in the bones and allowed some guests to take away all of the bones.
Paleontology in New Jersey | Scientific research
In 1931 and 1932, John Willis Stovall uncovered remains of a large theropod near Kenton in Cimarron County, Oklahoma in layers of the late Kimmeridgian. In 1941, these were named "Saurophagus maximus" by Stovall in an article by journalist Grace Ernestine Ray. The generic name is derived from Greek σαυρος, ', "lizard", φάγειν, ', "to eat", with the compound meaning of "lizard eater". The specific epithet "maximus" means "the largest" in Latin. Because the naming article did not contain a description, the name remained a "nomen nudum". In 1987, Spencer George Lucas erroneously made OMNH 4666, a tibia, the lectotype, unaware that "Saurophagus" was a "nomen nudum".
Saurophaganax | Discovery and naming
Where the fossil materials were collected in the same location, and were proportional. Based on that, was suggested these materials represent different parts of the same sauropod. Being the first representative of the family Mamenchisauridae implies a high diversity of sauropods in the late Early Jurassic. The specimen was kept at Chengdu University of Technology Museum, with the number MCDUT 14454.
Tonganosaurus | History of discovery
Ngwevu (pronounced 'Ng-g'where-voo; directly from Xhosa 'ngwevu' and 'intloko' meaning "grey skull") is a genus of massospondylid sauropodomorph dinosaur from the Lower Jurassic Elliot Formation of South Africa. The type and only known specimen, BP/1/4779, was discovered in 1978 by James William Kitching. It had in 1990 and 2004 been regarded as an unusual specimen of the related "Massospondylus", with a horizontally and vertically compressed skull, but in 2019 the specimen was after restudy concluded to belong to a new distinct genus. The genus is primarily distinguished by its skull being more robust than that of "Massospondylus".
Ngwevu | Introduction
The generic name is a contraction of "Thecospondylus" and "Coelurus". The holotype, NHMUK PV R181, was found in debris from a layer of the Wessex Formation, dating from the Barremian. It consists of the anterior end, about a third, of a cervical vertebra estimated by Seeley to have been nine centimetres long.
Thecocoelurus | Discovery and naming
Canadian paleontologist Lawrence Morris Lambe discovered the first specimen on 18 August 1897 in the area of the present Dinosaur Provincial Park, in the valley of the Red Deer River, Alberta, Canada. In 1902, this fossil, CMN 210 (also NMC 210) was designated as the holotype specimen of the type species "Stereocephalus tutus". This specimen consists of the upper part of a cranium and a transverse series of five scutes that were part of a cervical half ring. The generic name was derived from Greek στερεός, "stereos", "solid", and κεφαλή, "kephalè", "head", which refers to the formidable armour. However, the genus name was already "preoccupied" — the name had already been given to an insect, the beetle "Stereocephalus" Lynch 1884 — so Lambe changed it to "Euoplocephalus" in 1910, with as "combinatio nova" (new combination name) "Euoplocephalus tutus".
Euoplocephalus | Discovery and species
"Bathyspondylus" lived during the Kimmeridgian faunal stage of the Jurassic period, which occurred roughly 155 to 150 million years ago. The first of its fossils came from deposits near Swindon in Wiltshire, England.
Bathyspondylus | Distribution
Bathyspondylus is an extinct genus of plesiosaur. It was first described in 1982 from a specimen originally found in 1774, now housed at the Devizes Museum. Because it is known only from its fossil vertebrae (and so few of those have been recovered), paleontologists are not entirely sure of the taxonomy of "Bathyspondylus"; the family it belongs to is not currently known. The type, and only known, species is B. swindoniensis, which was described from the same material as its genus.
Bathyspondylus | Introduction
The American palaeontologist Samuel W. Williston subsequently reviewed Hooley's article, disagreeing with some of his conclusions about the anatomy and classification of the animal. After Hooley's monograph, little was written about the animal for the rest of the 20th century, and no similar pterosaurs were found for decades. In 1993, the British palaeontologists Stafford C. Howse and Andrew C. Milner concluded that the holotype sacrum and only specimen of "O. cluniculus" did not belong to a pterosaur, but to a maniraptoran dinosaur (this conclusion had also been reached independently by the British palaeontologist Christopher Bennett). They pointed out that no detailed attempts had been made to compare the sacrum of "O.
Istiodactylus | History of discovery
Many species have been named, although most are no longer considered valid. "M. carinatus", named by Richard Owen, is the type species. Other named species include: "M. browni" Seeley, 1895, "M. harriesi" Broom 1911, "M. hislopi" Lydekker, 1890, "M. huenei" Cooper, 1981, "M. kaalae" Barrett 2009, "M. rawesi" Lydekker, 1890, and "M. schwarzi" Haughton, 1924. "M. browni", "M. harriesi", and "M. schwarzi" were all found in the Upper Elliot Formation of Cape Province, South Africa. All three are based on fragmentary material, and were regarded as indeterminate in the most recent review. "M. browni" is based on two cervical, two back, and three caudal vertebrae and miscellaneous hind limb elements.
Massospondylus | Species
In 1825 Étienne Geoffroy Saint-Hilaire accordingly named two crocodilian skulls as the genus "Steneosaurus", the one, specimen MNHN 8900, becoming "Steneosaurus rostromajor", the other, MNHN 8902, "S. rostrominor".
Streptospondylus | Discovery and naming
One study in 2007 concluded that basal sauropodomorphs like "Massospondylus" likely had abdominal and cervical air sacs, based on the evidence for them in sister taxa (theropods and sauropods). The study concluded that it was impossible to determine whether basal sauropodomorphs had a bird-like flow-through lung, but that the air sacs were almost certainly present.
Massospondylus | Respiratory system
The type species of "Atychodracon" was first described and named by Samuel Stutchbury in January 1846, as a species of the wastebasket taxon "Plesiosaurus". The specific name means "large-headed" in Greek in reference to the very large skull compared to the rest of the skeletal elements ""Plesiosaurus" megacephalus" had, relatively to other / actual species of "Plesiosaurus". The pliosauroid nature of ""Plesiosaurus" megacephalus" remained unnoted until a revision by Richard Lydekker in 1889. Lydekker recognized the rhomaleosaurid affinities of ""P." megacephalus", but because he and Harry G. Seeley "refused steadfastly to recognize the generic and specific names proposed by one another", he moved ""P." megacephalus" to the genus "Thaumatosaurus" which was regarded by him as a replacement to Seeley's "Rhomaleosaurus" - creating the new combination "T.
Atychodracon | History of discovery
Barrett (2000) proposed that basal sauropodomorphs supplemented their herbivorous diets with small prey or carrion. Gastroliths (gizzard stones) have been found in association with three "Massospondylus" fossils from the Forest-Sandstone in Zimbabwe, and with a "Massospondylus"-like animal from the Late Triassic of Virginia. Until recently, scientists believed that these stones functioned as a gastric mill to aid ingestion of plant material, compensating for its inability to chew, as it is the case in many modern birds. However, Wings and Sander (2007) showed that the polished nature and the abundance of those stones precluded a use as an effective gastric mill in most non-theropod dinosaurs, including "Massospondylus".
Massospondylus | Diet
hislopi". The following cladogram shows the position of "Massospondylus" within Massospondylidae, according to Fernando E. Novas and colleagues, 2011:
Massospondylus | Classification
"Coelurus" would prove to be the first named small theropod from the Morrison Formation, although at the time Marsh was not certain that it was a dinosaur. He returned to it in 1881 and provided illustrations of some bones, along with putting it in a new order (Coeluria) and family (Coeluridae). From there, the story becomes more complex. Apparently, the skeleton was scattered throughout the quarry, with the remains being recovered from September 1879 to September 1880. Marsh elected to place some of the material in a new species, "C. agilis", on the strength of a pair of fused pubic bones he thought belonged to an animal three times the size of "C.
Coelurus | History
A fossil of a large sauropod was discovered by the Argentine paleontologist Dr. Bernardo Javier González Riga in Mendoza province In 2016, the type species "Notocolossus gonzalezparejasi" was named and described by Bernardo Javier González Riga, Matthew Carl Lamanna, Leonardo Daniel Ortiz David, Jorge Orlando Calvo and Juan P. Coria. The generic name combines the Greek words νότος, "notos", "south wind", and κολοσσός, "kolossos", "giant statue", in reference to the provenance from the Southern Hemisphere and the gigantic size of the animal. The specific name honours Jorge González Parejas, for having studied the dinosaur fossils of Mendoza province for two decades.
Notocolossus | Discovery and naming
In the Spring of 1882, a friend of contractor Edward Cleminshaw during construction at Redhole Lane in Sherborne, discovered stone blocks with skull remains. The stones had been removed from a quarry at the back of a row of houses at Cold Harbour Road in Greenhill in West Dorset. In 1883, the fossils were by Richard Owen referred to the type species of "Megalosaurus", "Megalosaurus bucklandii". Owen considered the find especially useful to complete information on the head of "Megalosaurus" as few of its skull bones had been identified until then. After 1883, the reference was generally accepted. In 1964 however, Alick Donald Walker concluded that the specimen represented a separate species within the genus "Megalosaurus", due to its higher tooth count, but as yet did not name this species.
Duriavenator | Discovery
In 1910, the American geologist Mignon Talbot was walking with her sister Ellen to Holyoke, Massachusetts, when they passed a farm and noticed a small hill nearby. It had a gravel pit at one side, and was formed by an accumulation of sand, gravel, and boulders left by a receding glacier. Talbot noticed a white streak on a sandstone boulder at the bottom of the gravel pit, and upon discovering these were bones, she told her sister she had found a "real live fossil", since many fossil tracks had previously been discovered in the Connecticut Valley (which she had often taken her students to see), but few actual dinosaur skeletons, and none at Mount Holyoke.
Podokesaurus | Discovery
In fact, they are the longest such bones known in dinosaurs. Thus, the vertebrae were stored until 1999, when Dr. Cifelli gave them to a graduate student, Matt Wedel, to analyze as part of a project. Upon their realization of the find's significance, they issued a press release in October 1999, followed by official publication of their findings in the "Journal of Vertebrate Paleontology" in March 2000. The new species was named "S. proteles", and the holotype is OMNH 53062. The generic name comes from "sauros" (Greek σαύρος for "lizard"), and "Poseidon" (Ποσειδών), the sea god in Greek mythology, who is also associated with earthquakes, that facet styled as Ennosigaios or Enosikhthōn, "Earthshaker".
Sauroposeidon | Discovery
Earlier assigned to crocodilian groups, "Streptospondylus" was in the 20th century typically classified in the Megalosauridae. Recent analyses indicate that "Streptospondylus" is a tetanuran theropod. Allain in 2001 suggested that it was closely related to "Eustreptospondylus" in the Spinosauroidea. Roger Benson in 2008 and 2010 concluded that whether it is a megalosauroid, allosauroid, or a more primitive form cannot be determined because of its extremely fragmentary remains. Later cladistic analysis by Benson and colleagues from 2010 indicated that "Streptospondylus" was the sister species of "Magnosaurus" within the Megalosauridae. Carrano "et al." (2012) placed "Streptospondylus" at Megalosauria "incertae sedis" due to its fragmentary nature.
Streptospondylus | Phylogeny
Palaeospondylus gunni (Gunn's ancient vertebrae) is a mysterious, fish-like fossil vertebrate. Its fossils are described from Achanarras slate quarry in Caithness, Scotland. The fossil as preserved is carbonized, and indicates an eel-shaped animal up to in length. The skull, which must have consisted of hardened cartilage, exhibits pairs of nasal and auditory capsules, with a gill apparatus below its hinder part, and ambiguous indications of ordinary jaws. The phylogeny of this bizarre fossil has puzzled scientists since its discovery in 1890, and many taxonomies have been suggested. In 2004, researchers proposed that "Palaeospondylus" was a larval lungfish. Previously, it had been classified as a larval tetrapod, unarmored placoderm, an agnathan, an early stem hagfish, and a chimera.
Palaeospondylus | Introduction
This fossil was initially described under the name "Protobatrachus massinoti" by the French paleontologist Jean Piveteau in 1936. Much more detailed description were published more recently.
Triadobatrachus | Introduction
multidens" + the Greek "sauros" (=lizard). "Hexinlusaurus" was a small, fleet-footed herbivore. Other dinosaurs known from Dashanpu include the sauropod "Shunosaurus", the theropod "Gasosaurus", and the stegosaur "Huayangosaurus". Before being officially named "Hexinlusaurus", this genus was briefly known under the informal name "Proyandusaurus". This name originally appeared in an abstract attributed to Fabien Knoll, which was apparently published without his consent.
Hexinlusaurus | Introduction
wetherilli". The nearly complete specimen (catalogued as UCMP 37302) was made the holotype of the species, and the second specimen (UCMP 37303) was made the paratype. The specific name honored John Wetherill, a Navajo councilor whom Welles described as an "explorer, friend of scientists, and trusted trader". Wetherill's nephew, Milton, had first informed the expedition of the fossils. Welles placed the new species in "Megalosaurus" due to the similar limb proportions of it and "M. bucklandii", and because he did not find great differences between them. At the time, "Megalosaurus" was used as a "wastebasket taxon", wherein many species of theropods were placed, regardless of their age or locality.
Dilophosaurus | History of discovery
In 1855 geologist Ferdinand Vandeveer Hayden sent a number of fossils to paleontologist Joseph Leidy in Philadelphia. Hayden had collected them from the surface of a rock formation then known as the Great Lignite Formation (now recognized as part of the Lance Formation) in the Nebraska Territory, near the Grand River (present-day South Dakota). Among them were two caudal vertebrae and a phalanx. In 1856 Leidy named the type species "Thespesius occidentalis" for these three bones. The generic name is derived from Greek θεσπεσιος, "thespesios", "wondrous", because of the colossal size of the remains. Leidy avoided using the suffix "saurus" in the genus name because Vandiveer Hayden had claimed the bones came from a layer from the Miocene so there was a chance that the animal would turn out to be a mammal, though Leidy himself was convinced it was a dinosaurian.
Thespesius | History
The small head of "Massospondylus" was approximately half the length of the femur. Numerous openings, or fenestrae, in the skull reduced its weight and provided space for muscle attachment and sensory organs. These fenestrae were present in pairs, one on each side of the skull. At the front of the skull were two large, elliptical nares, which were roughly half the size of the orbits. The orbits were proportionally larger in "Massospondylus" than in related genera, such as "Plateosaurus". The antorbital fenestrae, smaller than those seen in "Plateosaurus", were situated between the eyes and the nose. At the rear of the skull were two more pairs of temporal fenestrae: the lateral temporal fenestrae immediately behind the eye sockets, which were shaped like an inverted "T" in "Massospondylus", and the supratemporal fenestrae on top of the skull.
Massospondylus | Cranial anatomy
Several other "Saurornithoides" species were named, though none of these is today seen as valid. In 1928, baron Franz Nopcsa coined "Saurornithoides sauvagei". However, this was the result of a printing error: he had planned to name a "Teinurosaurus sauvagei". In 1982, Kenneth Carpenter renamed "Stenonychosaurus inequalis" Sternberg 1932 into "Saurornithoides inequalis". Today this is usually seen as a junior synonym of "Troodon formosus". In 1991, George Olshevsky renamed "Pectinodon asiamericanus" Nesov 1985 into "Saurornithoides asiamericanus". In 1995 he made it a "Troodon asiaamericanus". In view of its provenance from the Cenomanian of Uzbekistan, it is usually seen as a different taxon from "Saurornithoides".
Saurornithoides | History of discovery
While the holotype remains were initially discovered in 1994, due to their unexpected age and unusual size they were initially misclassified as pieces of petrified wood. A more detailed analysis in 1999 revealed their true nature which resulted in a minor media frenzy, and formal publication of the find the following year.
Sauroposeidon | Introduction
In 1923, German paleontologist Friedrich von Huene wrote a paper on Jurassic and Cretaceous European carnivorous dinosaurs. In this paper, he examined a specimen (OUM J.12144) including an incomplete hip, a leg bone, and part of a backbone, assigning it to a new species of "Megalosaurus": "Megalosaurus parkeri". The specific name honours W. Parker who in the nineteenth century had collected the fossils near Jordan's Cliff at Weymouth. These bones were from the Oxford Clay Formation, which dates to the Upper Jurassic. In 1932, however, von Huene concluded it was a species of "Altispinax", "A. parkeri". In 1964, scientist Alick Walker decided these fossils were too different from "Altispinax", as they lacked the long vertebral spines, and named the new genus "Metriacanthosaurus".
Metriacanthosaurus | History of discovery
harriesi" is considered to be a "nomen dubium"). However, Vasconcelos and Yates (2004) found "Gryponyx" to be distinctive enough from other basal sauropodomorphs to be placed in its own genus. They found that it differs from other taxa by the following characteristics: total length of metacarpal I exceeds maximum proximal width and a long, narrow pubic apron with straight lateral margins. Although this publication wasn't formal, they conducted a cladistic analysis using Yates (2004) sauropodomorph matrix and found "Gryponyx" to be the most basal massospondylid. The same result was found by Lü Junchang "et al." (2010). Yates "et al." (2010) recovered "Gryponyx" in a trichotomy with Massospondylidae and Anchisauria.
Gryponyx | Description
Diplodocus (, , or ) is a genus of diplodocid sauropod dinosaurs whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a neo-Latin term derived from Greek διπλός ("diplos") "double" and δοκός ("dokos") "beam", in reference to the double-beamed chevron bones located in the underside of the tail, which were then considered unique. This genus of dinosaurs lived in what is now mid-western North America at the end of the Jurassic period. It is one of the more common dinosaur fossils found in the middle to upper Morrison Formation, between about 154 and 152 million years ago, during the late Kimmeridgian age.
Diplodocus | Introduction
In 1988 James Kitching found the holotype fossil of "Litargosuchus" in a field expedition in Eagles Crag, a farm near Barkly East in the Eastern Cape. The material recovered consisted of a near-complete skull with its mandible and several bones belonging to the postcranial skeleton. At the time, Kitching was the director of the Evolutionary Studies Institute (previously the Bernard Price Institute) of the University of the Witwatersrand in Johannesburg. Kitching brought the holotype fossil back to the institute where he described it with fellow researcher, Christopher Gow. Together Kitching and Gow unfortunately misidentified this new species of sphenosuchian crocodylomorph and assigned the fossils to an existing crocodylomorph species, "Pedeticosaurus leviseuri".
Litargosuchus | History of Discovery
The forelimbs were only half the length of the hindlimbs but quite powerful, as indicated by the broad upper end of the humerus that provided attachment areas for a large arm musculature. Like "Plateosaurus", it had five digits on each hand and foot. The hand was short and wide, with a large sickle shaped thumb claw used for feeding or defense against predators. The thumb was the longest finger in the hand, while the fourth and fifth digits were tiny, giving the forepaws a lopsided look.
Massospondylus | Description