Sauropods ( or ), or sauropod ( ; sauro- -pod , "lizard-footed"), is a clade of a saurischian dinosaur ("lizard-hipped"). They have very long necks, long tails, small heads (relative to the rest of their body), and four feet thick like a pillar. They are famous for the large size achieved by several species, and the group is among the largest animals ever to live on land. Famous genera include Brachiosaurus , Diplodocus , Apatosaurus and Brontosaurus .
Sauropods first appeared in the Triassic Period End, where they resembled a closely related (and possibly ancestral) group of "Prosauropods". At the Jurassic End (150 million years ago), sauropods have become widespread (mainly diplodocids and brachiosaurids). At the Cretaceous End, the groups were primarily replaced by titanosaurs, which had almost global distributions. However, like all the other non-avian dinosaurs living at the time, the titanosaurs died in the Cretaceous-Paleogene extinction event. The remains of sauropod fossils have been found on every continent, including Antarctica.
The name Sauropoda was created by O.C. Marsh in 1878, and derived from Greek, meaning "lizard's feet". Sauropoda is one of the most recognizable groups of dinosaurs, and has become a fixture in popular culture because of its large size.
Complete findings of fossil sauropods are rare. Many species, especially the largest, are known only from isolated and disarticulated bones. Many almost complete specimens have no head, tail end and limbs.
Video Sauropoda
Deskripsi Edit
Sauropods are herbivores (plant-eating), usually four-legged long-necked (four-legged), often with spatulate (spatula-shaped: wide at the tip, narrowed in the neck) of the tooth. They have small heads, big bodies, and most have long tails. Their back legs are thick, straight and strong, ending at the foot like a club with five toes, though only three inside (or in some cases four) have claws. Their forelimbs are somewhat slimmer and end up in the hands like pillars built to support weight; just thumbs that have claws. Many illustrations of sauropods in the flesh lose these facts, inaccurately depicting sauropods with nails that restrict less clawed feet, or many claws or fingernails on the hands. Proximal diagnostic proximal venebra is highly diagnostic for sauropods.
Size Edit
The defining characteristic of sauropods is their size. Even the dwarf sauropods (perhaps 5 to 6 meters, or 20 feet long) are counted among the largest animals in their ecosystem. Their only real competitor in terms of size is the rorqual, like the blue whale. However, unlike whales, sauropods are mainly land animals.
Their body structure does not vary just like any other dinosaur, probably because of size limits, but they display a lot of variety. Some people, like diplodocids, have very long tails, which may crack like whips as a signal or to block or hurt predators, or to make sonic explosions. Supersaurus , 33 to 34 meters long (108 to 112 feet), is the longest known sauropod of relatively complete remains, but others, like the old record holder, Diplodocus i>, also very long. The holotype (and now missing) vertebra of Amphicoelias fragillimus may be from a 58-meter (190-feet) animal; The vertebral column is substantially longer than the blue whale. However, a study published in 2015 speculates that estimates of the size of A. fragillimus may be greatly exaggerated. The longest known dinosaur of a plausible fossil material is probably Argentinosaurus huinculensis with an estimated length of 25 meters (82 × ft) to 39.7 meters (130 × ft).
The longest living terrestrial animal, python reticulated, reaches only 6.95 meters (22.8 feet) long.
Others, such as brachiosaurids, are very tall, with high shoulders and very long necks. Sauroposeidon may be the highest, reaching about 18 meters (60 feet), with the previous record for the longest neck held by Mamenchisaurus . By comparison, giraffes, terrestrial animals are the highest, only 4.8-5.5 meters (16 to 18 feet).
The best evidence shows that the most massive are Argentinosaurus (73 metric tons), Puertasaurus (80 to 100Ã, metric tons), Alamosaurus , > Paralititan , Antarctosaurus (69 metric tons). There is poor (and now missing) evidence called Bruhathkayosaurus , probably weighing over 175 metric tons but this has been questioned. The weight of Amphicoelias fragillimus is estimated to be 122.4 metric tons but the 2015 study argues that this estimate may be greatly exaggerated. The largest living land animal today, the Savannah elephant, weighs no more than 10.4 metric tons (11.5 short tons).
Among the smallest sauropods are primitive Ohmdenosaurus (4 m, or 13 feet long), the dwarf titanosaur Magyarosaurus (6 m or 20 feet), and the dwarf brachiosaurid Europasaurus , which is 6.2 meters in length as an adult. His small stature is probably the result of an insular dwarf occurring in the sauropod populations isolated on the final Jurassic island in the Langenberg region now in northern Germany. The diplodocoid sauropod Brachytrachelopan is the shortest member of his group because of his unusually short neck. Unlike other sauropods, whose necks can grow up to four times the length of their backs, the Brachytrachelopan neck is shorter than its spine.
On or just before 29 March 2017, a 5.6 foot (1.7 meter) sauropod trail was found at Walmadany in Kimberley Region of Western Australia. The report says it is the largest known.
Limbs and feet Edit
As a large four-legged animal, sauropods develop specialized limbs (weight lifting). The back legs are wide, and retain three claws in most species. Very unusual compared to other animals is the highly modified front foot ( manus ). The sauropod's front legs are very different from those of modern big four-legged people, like elephants. Instead of stretching out to the side to create wide legs like elephants, the bones of the sauropods are arranged in full vertical columns, with very reduced finger bones (although it is unclear whether the most primitive sauropods, such as Vulcanodon and Barapasaurus , has a front leg like that). The forelegs are so modified in eusauropods that they will not be seen in life.
The arrangement of the front bone columns ( metacarpal ) in the easauropoda is semicircular, so that the sauropod front fingerprints are horseshoe shaped. Unlike elephants, printed evidence suggests that sauropods lack a fleshy bearing to support the forefoot, making them sunken. The only claws seen in most sauropods are typical thumb claws (associated with the I digit). Almost all sauropods have such claws, although what purpose is presented is unknown. The claws are the largest (as well as tall and laterally flat) on the diplodocids, and are very small in the brachiosaurids, some of which seem to have lost their claws entirely on the basis of the trail evidence.
Titanosaurs may have lost the thumb claw completely (with the exception of the initial form, such as Janenschia ). Titanosaurs are the most unusual among sauropods, because in addition to the external claws, they actually lose the toes. Advanced titanosaurs do not have digit or bone digits, and run only on a horseshoe-shaped "stump" made from a columnar metacarpal bone.
Printed evidence from Portugal suggests that, at least in some sauropods (possibly brachiosaurids), the underside and sides of the forefoot column are likely to be enclosed on a small, spiked scale, which leaves a mark of the score in the mold. In titanosaurs, the ends of metacarpal bone in contact with very large and dense soil, and some specimens retain the remains of soft tissue covering this area, indicating that the forefoot is framed with a kind of padding in this species.
Matthew Bonnan has shown that long sauropode dinosaur bones grow isometrically: that is, there is little or no change in shape when teen sauropods become giant adults. Bonnan suggests that this peculiar pattern of scales (mostly vertebrates showing significant changes in bone length associated with increased weight support) may be linked to the walker-walker principle (suggested by amateur scientist Jim Schmidt) in which long legs of adult sauropods allow them to easily cover up long distances without altering their overall mechanics.
Airbag Edit
Along with other saurischian dinosaurs (such as birds and other theropods), sauropods have air bag systems, evidenced by hollow indentations and cavities in most of their spines that have been attacked by them. Pneumatic, hollow bone is a characteristic feature of all sauropods. This air space reduces the overall weight of the large neck of the sauropod, and the air bag system in general, enables a single-direction air flow through the rigid lungs, allowing the sauropods to obtain sufficient oxygen.
The curvature of bird-like sauropods is recognized early in this animal study, and, in fact, at least one sauropod specimen discovered in the nineteenth century ( Ornithopsis ) was initially misidentified as a pterosaur (a flying reptile) because of this.
Armor Edit
Some sauropods have armor. There are genera with small clubs on their tails, like Shunosaurus, and some titanosaurs, such as Saltasaurus and Ampelosaurs, have small bone osteoderms that cover part of their bodies.
Teeth Edit
A study by Michael D'Emic and colleagues from Stony Brook University found that sauropods evolved high tooth replacement rates to keep up with their great appetite. Research shows that Nigersaurus , for example, replaces every tooth every 14 days, Camarasaurus replaces every tooth every 62 days, and Diplodocus replaces each tooth. every 35 days. Scientists found the quality of the teeth affected how long it took for new teeth to grow. Camarasaur teeth take longer to grow than those for
It was also noted by D'Emic and his team that the difference between sauropod teeth also shows differences in diet. Diplodocus takes the low ground to the ground and Camarasaurus finds the leaves from the upper and middle branches. According to scientists, their food specialties help different herbivore dinosaurs to co-exist.
Neck Edit
The neck of Sauropoda has been found with a length of more than 50 feet, six times longer than the world record of the giraffe's neck. Enabling this is a number of important physiological features. The large body size of the dinosaurs and quadrupedal position provide a stable base to support the neck, and the head evolves into very small and light, losing the ability to process food orally. By reducing their heads to the simple harvesting crops that bring the plants into the body, sauropods require less power to lift their heads, and thus are able to develop the neck with more dense muscles and connective tissue. This drastically reduces the overall mass of the neck, allowing further elongation.
Sauropods also have many adaptations in their skeletal structure. Some sauropods have as many as 19 cervical vertebrae, whereas almost all mammals are limited to only seven. In addition, each vertebra is very long and has a certain amount of empty space in it that will be filled only with air. The air-pocket system connected to the chambers not only relieves the long neck, but also effectively improves the flow of air through the trachea, helping the creature to breathe in enough air. By developing a vertebra consisting of 60% air, sauropods are able to minimize the amount of bone that is solid and heavy without sacrificing the ability to take a large enough breath to fill the whole body with oxygen. According to Kent Stevens, the reconstruction of computer models of skeletons made from vertebra shows that the sauropods' necks are capable of sweeping large dining areas without the need to move their bodies, but can not be pulled to position far above the shoulders to explore the region or reach higher.
Another proposed function of the long sauropod neck is essentially a radiator to overcome the extreme amounts of heat generated from their large body mass. Considering that metabolism will do a lot of work, it will definitely produce a large amount of heat as well, and the removal of this excess heat will be essential for survival. It has also been suggested that the long neck will cool the blood vessels and arteries to the brain, avoiding blood that is too hot to reach the head. In fact it was found that the increased metabolic rate resulting from the sauropods' neck was little more than compensated by the extra surface area from which heat could disappear.
Maps Sauropoda
Palaeobiology Edit
Ecology Edit
When sauropods were first discovered, their large size caused many scientists to compare them with modern-day whales. Most of the research in the nineteenth and early twentieth centuries concluded that sauropods were too large to sustain their weight on land, and therefore they were primarily aquatic. Most restoration of sauropod life in art through the first three quarters of the 20th century describes them entirely or partially immersed in water. This initial idea was questioned in the 1950s, when a study by Kermack (1951) showed that, if the animal was submerged in several meters of water, the pressure would be sufficient to destroy the lungs and airways fatal. However, these and other early studies of sauropod ecology have disadvantages because they ignore substantial evidence that the sauropods are so impregnated with air sacs. In 1878, paleontologist E.D. Cope even calls this structure a "buoy".
Beginning in the 1970s, the effects of the air sacs of sauropods on their aquatic lifestyles began to be explored. Paleontologists such as Coombs and Bakker use this, as well as evidence from sedimentology and biomechanics, to show that sauropods are terrestrial animals. In 2004, D.M. Henderson notes that, because of their vast airbag system, sauropods will drift and will not be able to drown their torsos completely beneath the surface of the water; in other words, they will float, and will not be in danger of collapsing lungs due to water pressure when swimming.
The evidence for swimming in sauropods is derived from traces of fossils that have sometimes been found to retain only the front footprints (manus). Henderson suggests that such traces may be explained by sauropods with long forelimbs (such as macronarians) floating in relatively shallow water deep enough to keep the shorter back foot free from the bottom, and using the front foot to punt the forwards. However, due to the proportion of their bodies, floating sauropods will also be highly unstable and maladapted for a long time in the water. This aquatic propulsion mode, combined with its instability, prompted Henderson to refer sauropods into the water as "drunk passengers".
While sauropods can not be as aquatic as historically depicted, there is evidence that they prefer wet and coastal habitats. Sauropod footprints are usually found along shorelines or across floodplains, and fossils of sauropods are often found in wet environments or mixed with fossils of marine organisms. A good example of this is the large Jurassic sauropod trajectory found in the lagoon deposit in Isle of Skye, Scotland.
Pastoral care and care Edit
Many fossil evidence lines, both from bed bones and lane pathways, show that sauropods are gregarious animals that make up the herd. However, the arrangement of flocks varies between species. Some bone beds, such as a site from Central Jurassic Argentina, seem to show a collection of people from different age groups, mixing teenagers and adults. However, a number of fossil sites and other pathways indicate that many species of sauropods travel in groups separated by age, with adolescents forming a herd separated from adults. Such segregated grazing strategies have been found in species such as Alamosaurus , Bellusaurus and some diplodocids.
In the evidence review for different types of cattle, Myers and Fiorillo sought to explain why sauropods seem to often form separate groups. Studies using microscopic teeth suggest that juvenile sauropods have different foods than adults, so joint grazing will not be as productive as grazing separately, where individual group members can feed in a coordinated way. Large size differences between adolescents and adults can also play a role in different feeding and grazing strategies.
Because the separation of adolescents and adults should be done immediately after hatching, and combined with the fact that sauropods are likely to be precocial, Myers and Fiorillo conclude that species with age-separated herds will not show much parental care. On the other hand, scientists who have studied aggregated sauropods suggest that this species may take care of their child for a long period of time before young adulthood. A 2014 study suggests that the time from laying eggs up to the time of hatching is possible between 65 and 82 days. Exactly how separated versus mixed age ages varies across the various groups of unknown sauropods. Further examples of gregarious behavior need to be found from more sauropod species to begin detecting possible distribution patterns.
Maintain attitude Edit
Since the beginning of the history of their studies, scientists, such as Osborn, have speculated that sauropods can turn their backsides, using the tail as the third 'leg' of the tripod. Skeletal skeletons depicting diplodocid Barosaurus lentus raising hind legs at the American Museum of Natural History are one illustration of this hypothesis. In a 2005 paper, Rothschild and Molnar reasoned that if sauropods had adopted bipedal posture at times, there would be evidence of stress fractures in the 'forelegs'. However, nothing was discovered after they examined a large number of sauropod skeletons.
Heinrich Mallison (in 2009) was the first to study the physical potential for various sauropods backwards to tripodal attitudes. Mallison found that some of the characters previously associated with maintenance adaptations were virtually unrelated (such as wide titanosaur hip bones) or would impede maintenance. For example, the titanosaurs have incredibly flexible backbones, which will lower the stability in the tripod position and will overload the muscles. Likewise, it is unlikely that brachiosaurids can support the hind legs, because their center of gravity is much more advanced than other sauropods, which will cause the horses to become unstable.
Diplodocids, on the other hand, seem to have adapted well to magnify into a tripodal attitude. Diplodocids have a mass center directly above their hips, giving them a greater balance on two legs. Diplodocids also have the most mobile sauropod neck, a well-muscled pelvic corset, and a tail spindle with a special shape that will allow the tail to bear the weight at that point touching the ground. Mallison concludes that diplodocids are better adapted to be raised than elephants, which are sometimes done in the wild. He also argues that stress fractures in the wild do not occur from everyday behaviors, such as eating-related activities (counter Rothschild and Molnar).
Head and neck position Edit
There is controversy about how sauropods hold their heads and necks, and the posture they can achieve in life. Various studies looking at issues of aspects, such as the neutral articulation of the neck vertebra and estimate range of motion, metabolic requirements and energy have very long necks, and comparisons with living animals, have come to different conclusions. The claim that the long sauropod neck used to roam the tall trees has been questioned on the basis of calculating the energy needed to create arterial blood pressure for the head if held upright. This calculation shows this will take approximately half of its energy intake. Furthermore, to supply blood to the head that is held vertically high would require blood pressure around 700 mmHg (= 0.921 bar) in the heart. This will require a heart 15 times the size of a whale's heart of the same size. It has been used to argue that it is more likely that long necks are usually held horizontally to allow them to feed the plants in a very large area without the need to move their bodies - a potentially huge energy savings for 30 to 40 tons of animals. To support this, neck reconstruction of Diplodocus and Apatosaurus shows that they are essentially straight with a gentle decline that orientates their head and neck in "neutral and undetected posture".
However, research on living animals argues that most living tetrapods usually raise the base of their necks when alert. The conclusion of the bone on "neutral posture", which indicates a more horizontal position, may be unreliable. A study published in 2013 that is studied in the ostrich neck will, however, take the approximate flexibility of the sauropod neck as a doubt. The study by Matthew Cobley et al reveals, using computer modeling, that muscle attachment and cartilage present at the neck are likely to limit flexibility to a considerable degree. The authors caution against estimating the range of motion from using only bones alone. The discovery also reveals that sauropods may have to move their entire body around to access better areas where they can graze and trace vegetation.
Trackways and locomotion Edit
The traces of Sauropoda and other fossil tracks (known as "ichnites") are known from the abundance of evidence that exists on most continents. Ichnites have helped support other biological hypotheses about sauropods, including the anatomy of the forelegs and back (see limbs above). Generally, the mold from the front foot is much smaller than the hind legs, and is often crescent-shaped. Sometimes ichnite preserves claw footprints, and helps confirm groups of sauropods who lose their claws or even digits on their forelegs.
Sauropods tracing from the Villar del Arzobispo Formation from Early Berriasian age in Spain supported group behavior of the group. The trail may be more similar to Sauropodichnus giganteus than any other ichnogenera, although they are suggested to be from basal-shaped titanosaurs. The tracks are very wide, and the groupings close to Sauropodichnus are also supported by the manus-to-pes distance, the morphology of the kidney-shaped kidney beast, and the morphology of the plague to be subtriangular. It can not be identified whether the herd's footprints are caused by teenagers or adults, due to the lack of identification of the age of the previous trajectory individual.
Sometimes, only footprints of the forefoot are found. Falkingham et al. using computer modeling to show that this could be due to the nature of the substrate. This should be appropriate to maintain the track. Differences in the hind legs and front limb surface area, and therefore contact pressure with the substrate, can sometimes cause only the preserved front footprints.
Biomechanics and speed Edit
In a study published in PLoS ONE on October 30, 2013, by Bill Sellers, Rodolfo Coria, Lee Margetts et al. , Argentinosaurus is reconstructed digitally to test its driver for the first time. Prior to the study, the most common way of estimating speed was through studying bone histology and ichnology. Generally, research on the histology of the sauropod bone and the focusing velocity of the postcranial skeleton, which holds many unique features, such as the enlarging process of the ulna, the width of the lobe in ilia, the inner third into the inner femur, and the very axis of the ovoid femur. These features are useful when trying to explain the patterns of animal trajectories of graviportal. When studying ichnology to calculate the speed of sauropods, there are some problems, such as providing only an approximation to a particular echo because of preservation bias, and being subject to many accuracy problems.
To estimate the speed and velocity of Argentinosaurus , this study performed a musculoskeletal analysis. The only previous musculoskeletal analysis was performed on hominoids, birds of terror, and other dinosaurs. Before they can perform the analysis, the team must create the animal's digital skeleton, showing where there will be layering of muscles, finding muscles and joints, and finally discovering muscle properties before finding speed and speed. The results of a biomechanical study reveal that Composite Argentinosaurus is competently mechanized at a top speed of 2 m/s (5 mph) given the large weight of animals and strains that the joints are able to withstand. The results further reveal that much larger terrestrial vertebrates may be possible, but will require significant body remodeling and possible behavioral changes sufficient to prevent collapse together.
Body size Edit
Giant sauropods, and very small ancestors of ancestors. Basal dinosaurs, such as Pseudolagosuchus and Marasuchus from the Argentine Central Triass, weighed about 1 kg (2.2 pounds) or, in most cases, less. At an evolutionary point called Saurischia, a rapid increase in bauplan sizes appears, although more primitive members such as Eoraptor , Panphagia , Pantydraco , Saturnalia and Guaibasaurus still maintain medium size, maybe even less than 10 kg (22 pounds). Even with these small primitive forms, there is a striking growth in size in sauropodomorph, although the small remains of this sauropod evolutionary period make the assumptions necessary because their size is difficult to interpret. There is one definite example of the reduced sauropodomorph, and it is Anchisaurus , which reaches below 50 kg (110 pounds), though closer to the sauropod than Plateosaurus and < i> Riojasaurus , which is higher than 1 t (0.98 ton long, 1.1 ton short) weight.
Compared with sauropodomorph, sauropods are also very large. Their larger size may be generated due to an increased rate of growth, which seems to have been associated with tachymetabolic endothermy, a condition that evolved in sauropodomorphs. After branching into sauropods, sauropodomorphs continued to grow larger, with smaller sauropods, such as the Early Jurassic Barapasaurus and Kotasaurus, evolving into larger forms such as Central Jurassic > Mamenchisaurus and Patagosaurus . Following the size change of sauropods, theropods continue to grow even larger, which is represented by coelofoils from Germany (Allosaurus). As one possible explanation for an increased body size is less predation risk, evolution of sauropod and theropod size may be related.
Size in Neosauropoda Edit
Neosauropoda is probably the largest ever dinosaur clade, with few exceptions. Most exceptions are hypothesized to be caused by island dwarfs, although there is a tendency in Titanosauria to smaller body sizes. However, the titanosaurs are also the largest sauropods ever. In addition to titanosaurs, the clade of diplodocoids, a giant group, called Dicraeosauridae, was diagnosed with a small body size. There are no very small sauropods; however, even the "dwarf" saveropods are greater than 500 kg (1,100 pounds), a measure achieved by only about 10% of all mammalian species.
Independent gigantism Edit
Although in general, large sauropods, gigantic sizes (40 tonnes (39 ton long, 44 ton short) or more) were independently achieved at several times in their evolution. Many of the gigantic forms exist in the Jurassic End (especially Kimmeridgian and Turonian), such as turiasaur Turiasaurus and diplodocoids Amphicoelias Diplodocus and Supersaurus . Through the Cretaceous Beginning to the End, the giants of Sauroposeidon Paralititan , Argentinosaurus , Puertasaurus , Antartosaurus giganteus < i>, Dreadnoughtus schrani , Notocolossus and Futalognkosaurus live, the earliest being brachiosaurid, with the latter being a titanosaurus. One of the rarely known giants is Huanghetitan ruyangensis , known only from long ribs of 3 m (9.8 ft). All genera and giant species live in the Jurassic End to the Lime End, over a span of 85 million years, and independently evolved neosauropods. Insular dwarfs in sauropod Edit
Insular dwarfism is caused by a reduced rate of growth in the sauropod, the reverse causing the evolution of sauropods. Two of the island's most famous dwarfs are Cretaceous Magyarosaurus (at one point its identity as dwarf is challenged) and Jurassic Europasaurus , both from Europe. Although these sauropods are small, the only way to prove that they are true dwarfs is through their histology of bone studies. A study by Martin Sander and colleagues in 2006 examined eleven individuals using Europasaurus holgeri using bone histology and showed that small island species evolved through decreasing long bone growth rates compared with the growth rate of the terrestrial species on the land. Two other possible dwarves are Rapetosaurus, which is on the island of Madagascar, a remote island in Cretaceous, and Ampelosaurus, a titanosaur living on the Iberian peninsula in southern Spain. and France. The possibility of Cetiosauriscus from Switzerland may also be dwarfed, but that has not been proven. One of the most extreme cases of island dwarfism is found in Europasaurus , a much larger relative of Camarasaurus and Brachiosaurus , about 6.2 m ( 20Ã, ft) long, and small size Europasaurus is considered the genus diagnostic. The reason for the size reduction found by the author is the reduced rate of growth, which is now considered why all the dwarves are so small.
Discovery history Edit
The first random fossils left now known as sauropods all originated in England and were originally interpreted in different ways. Their relationship with other dinosaurs was not recognized until after their initial discovery.
The first scientifically described fossil of the sauropod is a single tooth known by the non-Linnaean descriptors Rutellum implatum . This fossil was described by Edward Lhuyd in 1699, but was not recognized as a giant prehistoric reptile at the time. Dinosaurs will not be recognized as a group until more than a century later.
Richard Owen published the first modern scientific description of sauropods in 1841, in his paper naming the Cetiosaurus
In 1850, Gideon Mantell recognized the dinosaurian character of several bones assigned to Owen's Cetiosaurus. Mantell noticed that the leg bones contain medullary cavities, the characteristics of terrestrial animals. He assigned these specimens to the new genus Pelorfaurus, and grouped them together with the dinosaurs. However, Mantell still does not recognize the relationship with Cetiosaurus .
The next sauropod found to be described and misidentified as something other than the dinosaur was a set of hip vertebrae described by Harry Seeley in 1870. Seeley found that very light spine was constructed for their size and contained openings for air sacs ( pneumatization >). Such airbags were known only to birds and pterosaurs, and Seeley considered them to be derived from pterosaurs. He named the new genus Ornithopsis , or "bird face" because of this.
When the more complete specimen of the Cetiosaurus was described by Phillips in 1871, he finally recognized the animal as a dinosaur associated with Pelorosaurus . However, it was not until the new description, the almost complete sauropod skeleton of the United States (representing Apatosaurus and Camarasaurus) that year that a complete picture of sauropod emerged. The complete reconstruction of skeletal sauropods is produced by artist John A. Ryder, hired by paleontologist E.D. Cope, based on the remains of Camarasaurus , although many features are still inaccurate or incomplete according to later findings and biomechanical studies. Also in 1877, Richard Lydekker named other relatives of Cetiosaurus, Titanosaurus, based on isolated vertebrae.
In 1878, the most complete sauropods have not been discovered and described by Othniel Charles Marsh, who named them the "Diplodocus . With these findings, Marsh also created new groups containing Diplodocus , Cetiosaurus , and a growing list of family members to distinguish them from other large groups of dinosaurs. Marsh named this group Sauropoda, or "lizard's feet".
Classification Edit
The classification of sauropods has been largely stable in recent years, although there are still some uncertainties, such as the placement of Euhelopus Haplocanthosaurus , Jobaria and Nemegtosauridae.
Cladogram after analysis presented by Sander and colleagues in 2011.
References Edit
- Bob Strauss, 2008, Sauropoda: The Largest Dinosaur Who Ever Lived, The New York Times
- Kristina Curry Rogers and Jeffrey A. Wilson, 2005,
- Upchurch, P., Barrett, P.M. and Dodson, P. 2004. Sauropods. In The Dinosauria , 2nd ed. D. Weishampel, P. Dodson, and H. OsmÃÆ'³lska (eds.). University of California Press, Berkeley. Pp.259-322.
Source of the article : Wikipedia
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