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105-484: Diplodocids , or members of the family Diplodocidae ("double beams"), are a group of sauropod dinosaurs . The family includes some of the longest creatures ever to walk the Earth, including Diplodocus and Supersaurus , some of which may have reached lengths of up to 42 metres (138 ft). Diplodocids were generally large animals, even by sauropod standards. Thanks to their long necks and tails, diplodocids were among

210-420: A nomen oblitum in 1991, though scientists such as Steel and Nowinski had treated Atlantosauridae as a valid name as late as 1971, and the former even added a subfamily, Atlantosaurinae . Some dinosaurs have been considered diplodocids in the past but have not been found to be members of that group in later, larger analyses of the family's relationships. Australodocus , for example, was initially described as

315-495: A basal titanosauriform. The tracks are wide-gauge, and the grouping as close to Sauropodichnus is also supported by the manus-to-pes distance, the morphology of the manus being kidney bean-shaped, and the morphology of the pes being subtriangular. It cannot be identified whether the footprints of the herd were caused by juveniles or adults, because of the lack of previous trackway individual age identification. Generally, sauropod trackways are divided into three categories based on

420-420: A bipedal posture at times, there would be evidence of stress fractures in the forelimb 'hands'. However, none were found after they examined a large number of sauropod skeletons. Heinrich Mallison (in 2009) was the first to study the physical potential for various sauropods to rear into a tripodal stance. Mallison found that some characters previously linked to rearing adaptations were actually unrelated (such as

525-521: A characteristic feature of all sauropods. These air spaces reduced the overall weight of the massive necks that the sauropods had, and the air-sac system in general, allowing for a single-direction airflow through stiff lungs, made it possible for the sauropods to get enough oxygen. This adaptation would have advantaged sauropods particularly in the relatively low oxygen conditions of the Jurassic and Early Cretaceous. The bird-like hollowing of sauropod bones

630-560: A diplodocid, but may actually have been a Macronarian . Amphicoelias was traditionally considered a diplodocid due to its similar anatomy, but phylogenetic studies showed it to be a more basal member of the Diplodocoidea. The relationships of species within Diplodocidae has also been subject to frequent revision. A study by Lovelace, Hartman and Wahl in 2008 found that Suuwassea and Supersaurus were relatives of Apatosaurus , within

735-402: A great number of adaptations in their skeletal structure. Some sauropods had as many as 19 cervical vertebrae , whereas almost all mammals are limited to only seven. Additionally, each vertebra was extremely long and had a number of empty spaces in them which would have been filled only with air. An air-sac system connected to the spaces not only lightened the long necks, but effectively increased

840-422: A large energy saving for such a large animal. Reconstructions of the necks of Diplodocus and Apatosaurus have therefore often portrayed them in near-horizontal, so-called "neutral, undeflected posture". However, research on living animals demonstrates that almost all extant tetrapods hold the base of their necks sharply flexed when alert, showing that any inference from bones about habitual "neutral postures"

945-513: A part in the different feeding and herding strategies. Since the segregation of juveniles and adults must have taken place soon after hatching, and combined with the fact that sauropod hatchlings were most likely precocial , Myers and Fiorillo concluded that species with age-segregated herds would not have exhibited much parental care. On the other hand, scientists who have studied age-mixed sauropod herds suggested that these species may have cared for their young for an extended period of time before

1050-484: A population of sauropods isolated on an island of the late Jurassic in what is now the Langenberg area of northern Germany . The diplodocoid sauropod Brachytrachelopan was the shortest member of its group because of its unusually short neck. Unlike other sauropods, whose necks could grow to up to four times the length of their backs, the neck of Brachytrachelopan was shorter than its backbone. Fossils from perhaps

1155-495: A position much above the shoulders for exploring the area or reaching higher. Another proposed function of the sauropods' long necks was essentially a radiator to deal with the extreme amount of heat produced from their large body mass. Considering that the metabolism would have been doing an immense amount of work, it would certainly have generated a large amount of heat as well, and elimination of this excess heat would have been essential for survival. It has also been proposed that

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1260-483: A review of the evidence for various herd types, Myers and Fiorillo attempted to explain why sauropods appear to have often formed segregated herds. Studies of microscopic tooth wear show that juvenile sauropods had diets that differed from their adult counterparts, so herding together would not have been as productive as herding separately, where individual herd members could forage in a coordinated way. The vast size difference between juveniles and adults may also have played

1365-401: A single action. Also, the palinal (backwards) motion of the lower jaws could have contributed two significant roles to feeding behaviour: 1) an increased gape, and 2) allowed fine adjustments of the relative positions of the tooth rows, creating a smooth stripping action. Young et al. (2012) used biomechanical modelling to examine the performance of the diplodocine skull. It was concluded that

1470-404: A stance to be unstable. Diplodocids, on the other hand, appear to have been well adapted for rearing up into a tripodal stance. Diplodocids had a center of mass directly over the hips, giving them greater balance on two legs. Diplodocids also had the most mobile necks of sauropods, a well-muscled pelvic girdle, and tail vertebrae with a specialised shape that would allow the tail to bear weight at

1575-455: A stilt-walker principle (suggested by amateur scientist Jim Schmidt) in which the long legs of adult sauropods allowed them to easily cover great distances without changing their overall mechanics. Along with other saurischian dinosaurs (such as theropods , including birds), sauropods had a system of air sacs , evidenced by indentations and hollow cavities in most of their vertebrae that had been invaded by them. Pneumatic, hollow bones are

1680-443: A symptom of cracking their tails: these are particularly common between the 18th and the 25th caudal vertebra, a region the authors consider a transitional zone between the stiff muscular base and the flexible whiplike section. However, Rega (2012) notes that Camarasaurus , while lacking a tailwhip, displays a similar level of caudal co-ossification, and that Mamenchisaurus , while having the same pattern of vertebral metrics, lacks

1785-413: A tailwhip and doesn't display fusion in any "transitional region". Also, the crush fractures which would be expected if the tail was used as a whip have never been found in diplodocids. More recently, Baron (2020) considers the use of the tail as a bullwhip unlikely because of the potentially catastrophic muscle and skeletal damage such speeds could cause on the large and heavy tail. Instead, he proposes that

1890-458: A tiny fraction is exposed and accessible to geologists and paleontologists . Over 75% is still buried under the prairie to the east, and much of its western paleogeographic extent was eroded during exhumation of the Rocky Mountains . It was named after Morrison, Colorado , where some of the first fossils in the formation were discovered by Arthur Lakes in 1877. That same year, it became

1995-414: A wide gauge and lack of any claws or digits on the forefeet. Occasionally, only trackways from the forefeet are found. Falkingham et al. used computer modelling to show that this could be due to the properties of the substrate. These need to be just right to preserve tracks. Differences in hind limb and fore limb surface area, and therefore contact pressure with the substrate, may sometimes lead to only

2100-551: Is a clade of saurischian ('lizard-hipped') dinosaurs . Sauropods had very long necks, long tails, small heads (relative to the rest of their body), and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land. Well-known genera include Apatosaurus , Argentinosaurus , Alamosaurus , Brachiosaurus , Camarasaurus , Diplodocus , and Mamenchisaurus . The oldest known unequivocal sauropod dinosaurs are known from

2205-429: Is a notable size increase among sauropodomorphs, although scanty remains of this period make interpretation conjectural. There is one definite example of a small derived sauropodomorph: Anchisaurus , under 50 kg (110 lb), even though it is closer to the sauropods than Plateosaurus and Riojasaurus , which were upwards of 1 t (0.98 long tons; 1.1 short tons) in weight. Evolving from sauropodomorphs,

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2310-456: Is a statement of the anatomical features of an organism (or group) that collectively distinguish it from all other organisms. Some, but not all, of the features in a diagnosis are also autapomorphies - distinctive anatomical features that are unique to a given organism or group. The clade Diplodocidae is distinguished based on the following characteristics: Few skin impressions of diplodocids have been found. However, at least one significant find

2415-453: Is deeply unreliable. Meanwhile, computer modeling of ostrich necks has raised doubts over the flexibility needed for stationary grazing. Sauropod trackways and other fossil footprints (known as "ichnites") are known from abundant evidence present on most continents. Ichnites have helped support other biological hypotheses about sauropods, including general fore and hind foot anatomy (see Limbs and feet above). Generally, prints from

2520-891: Is evidence that they preferred wet and coastal habitats. Sauropod footprints are commonly found following coastlines or crossing floodplains, and sauropod fossils are often found in wet environments or intermingled with fossils of marine organisms. A good example of this would be the massive Jurassic sauropod trackways found in lagoon deposits on Scotland 's Isle of Skye . Studies published in 2021 suggest sauropods could not inhabit polar regions. This study suggests they were largely confined to tropical areas and had metabolisms that were very different to those of other dinosaurs, perhaps intermediate between mammals and reptiles. New studies published by Taia Wyenberg-henzler in 2022 suggest that sauropods in North America declined due to undetermined reasons in regards to their niches and distribution during

2625-544: Is from the Bajada Colorada Formation of Argentina, and indeterminate diplodocid material is known from the nearby Mulichinco Formation of similar age. [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] Sauropod Sauropoda ( / s ɔː ˈ r ɒ p ə d ə / ), whose members are known as sauropods ( / ˈ s ɔːr ə p ɒ d z / ; from sauro- + -pod , ' lizard -footed'),

2730-626: Is shown in the fossil record. Moreover, it must be determined as to whether sauropod declines in North America was the result of a change in preferred flora that sauropods ate, climate, or other factors. It is also suggested in this same study that iguanodontians and hadrosauroids took advantage of recently vacated niches left by a decline in sauropod diversity during the late Jurassic and the Cretaceous in North America. Many lines of fossil evidence, from both bone beds and trackways, indicate that sauropods were gregarious animals that formed herds . However,

2835-412: Is the most likely feeding behavior of Diplodocus , as it explains the unusual wear patterns of the teeth (coming from tooth–food contact). In unilateral branch stripping, one tooth row would have been used to strip foliage from the stem, while the other would act as a guide and stabilizer. With the elongated preorbital (in front of the eyes) region of the skull, longer portions of stems could be stripped in

2940-421: Is unknown. The claw was largest (as well as tall and laterally flattened) in diplodocids, and very small in brachiosaurids, some of which seem to have lost the claw entirely based on trackway evidence. Titanosaurs may have lost the thumb claw completely (with the exception of early forms, such as Janenschia ). Titanosaurs were most unusual among sauropods, as, across their history as a clade, they lost not just

3045-484: The African elephant , can only reach lengths of 7.3 metres (24 ft). Others, like the brachiosaurids , were extremely tall, with high shoulders and extremely long necks. The tallest sauropod was the giant Barosaurus specimen at 22 m (72 ft) tall. By comparison, the giraffe , the tallest of all living land animals, is only 4.8 to 5.6 metres (15.74 to 18.3 ft) tall. The best evidence indicates that

3150-711: The Early Jurassic . Isanosaurus and Antetonitrus were originally described as Triassic sauropods, but their age, and in the case of Antetonitrus also its sauropod status, were subsequently questioned. Sauropod-like sauropodomorph tracks from the Fleming Fjord Formation ( Greenland ) might, however, indicate the occurrence of the group in the Late Triassic . By the Late Jurassic (150 million years ago), sauropods had become widespread (especially

3255-476: The ICZN , preventing it from displacing the name Diplodocidae as a senior synonym. More recent studies have also shown that Amphicoelias itself does not belong to this family, but is instead a more primitive diplodocoid. A similar situation occurred for the family name Atlantosauridae , named by Othniel Charles Marsh in 1877, and which Hay argued had priority over Amphicoelidae. George Olshevsky declared Atlantosauridae

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3360-488: The Morrison Formation nicknamed "Dolly" shows evidence of a throat infection that created cauliflowered bone in the vertebral air sacs. The infection is theorized to have been similar to aspergillosis , though research is ongoing. Whether or not the infection contributed to the dinosaur's death remains unknown. Diplodocids also had long, whip-like tails , which were thick at the base and tapered off to be very thin at

3465-473: The blue whale in size. The weight of Amphicoelias fragillimus was estimated at 122.4 metric tons with lengths of up to nearly 60 meters but 2015 research argued that these estimates were based on a diplodocid rather than the more modern rebbachisaurid, suggesting a much shorter length of 35–40 meters with mass between 80–120 tons. Additional finds indicate a number of species likely reached or exceeded weights of 40 tons. The largest land animal alive today,

3570-430: The bush elephant , weighs no more than 10.4 metric tons (11.5 short tons). Among the smallest sauropods were the primitive Ohmdenosaurus (4 m, or 13 ft long), the dwarf titanosaur Magyarosaurus (6 m or 20 ft long), and the dwarf brachiosaurid Europasaurus , which was 6.2 meters long as a fully-grown adult. Its small stature was probably the result of insular dwarfism occurring in

3675-548: The diplodocids and brachiosaurids ). By the Late Cretaceous , one group of sauropods, the titanosaurs , had replaced all others and had a near-global distribution. However, as with all other non-avian dinosaurs alive at the time, the titanosaurs died out in the Cretaceous–Paleogene extinction event . Fossilised remains of sauropods have been found on every continent, including Antarctica . The name Sauropoda

3780-497: The rorquals , such as the blue whale . But, unlike whales, sauropods were primarily terrestrial animals . Their body structure did not vary as much as other dinosaurs, perhaps due to size constraints, but they displayed ample variety. Some, like the diplodocids , possessed tremendously long tails, which they may have been able to crack like a whip as a signal or to deter or injure predators, or to make sonic booms . Supersaurus , at 33 to 34 metres (108 to 112 ft) long,

3885-458: The 1970s, the effects of sauropod air sacs on their supposed aquatic lifestyle began to be explored. Paleontologists such as Coombs and Bakker used this, as well as evidence from sedimentology and biomechanics , to show that sauropods were primarily terrestrial animals. In 2004, D.M. Henderson noted that, due to their extensive system of air sacs, sauropods would have been buoyant and would not have been able to submerge their torsos completely below

3990-432: The 19th and early 20th centuries concluded that sauropods were too large to have supported their weight on land, and therefore that they must have been mainly aquatic . Most life restorations of sauropods in art through the first three quarters of the 20th century depicted them fully or partially immersed in water. This early notion was cast in doubt beginning in the 1950s, when a study by Kermack (1951) demonstrated that, if

4095-650: The Bullington Member, which has been discarded entirely. Though many of the Morrison Formation fossils are fragmentary, they are sufficient to provide a good picture of the flora and fauna in the Morrison Basin during the Kimmeridgian. Overall, the climate was dry, similar to a savanna but, since there were no angiosperms ( grasses , flowers , and some trees ), the flora was quite different. Conifers ,

4200-818: The Diplodocidae after Tschopp, Mateus, and Benson (2015). Amphicoelias altus Unnamed species Apatosaurus ajax Apatosaurus louisae Brontosaurus excelsus Brontosaurus yahnahpin Brontosaurus parvus Unnamed species Tornieria africana Supersaurus lourinhanensis Supersaurus vivianae Leinkupal laticauda Galeamopus hayi Diplodocus carnegii Diplodocus hallorum Kaatedocus siberi Barosaurus lentus Diplodocids probably evolved in North America, where most diplodocid fossils are found. However, diplodocids have been found on most continents, including South America, Europe, and Africa. Diplodocids and their close relatives, dicraeosaurids, must have diverged from each other by

4305-459: The Middle Triassic of Argentina, weighed approximately 1 kg (2.2 lb) or less. These evolved into saurischia, which saw a rapid increase of bauplan size, although more primitive members like Eoraptor , Panphagia , Pantydraco , Saturnalia and Guaibasaurus still retained a moderate size, possibly under 10 kg (22 lb). Even with these small, primitive forms, there

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4410-561: The Mother's Day Quarry, it is hypothesized that the skin originated from a small or juvenile individual. Their teeth were only present in the front of the mouth, and looked like pencils or pegs. They probably used their teeth to crop off food, without chewing, and relied on gastroliths (gizzard stones) to break down tough plant fibers (similar to modern birds ). Diplodocines have highly unusual teeth compared to other sauropods. The crowns are long and slender, and elliptical in cross-section, while

4515-650: The Rocky Mountains started pushing up to the west. The deposits from their east-facing drainage basins , carried by streams and rivers from the Elko Highlands (along the borders of present-day Nevada and Utah) and deposited in swampy lowlands, lakes, river channels and floodplains , became the Morrison Formation. In the north, the Sundance Sea , an extension of the Arctic Ocean , stretched through Canada down to

4620-459: The United States. Coal is found in the Morrison Formation of Montana, which means that the northern part of the formation, along the shores of the sea, was wet and swampy, with more vegetation. Aeolian , or wind-deposited sandstones, are found in the southwestern part, which indicates it was much more arid—a desert , with sand dunes . The Morrison Formation is subdivided into several members,

4725-455: The age that a specific individual reached. A study by Griebeler et al. (2013) examined long bone histological data and concluded that the diplodocid MfN.R.2625 weighed 4,753 kilograms (5.2 short tons), reached sexual maturity at 23 years and died at age 24. The same growth model indicated that the diplodocid MfN.R.NW4 weighed 18,463 kilograms (20.4 short tons), and died at age 23, before reaching sexual maturity. An unnamed diplodocid specimen from

4830-550: The airflow through the trachea, helping the creatures to breathe in enough air. By evolving vertebrae consisting of 60% air, the sauropods were able to minimize the amount of dense, heavy bone without sacrificing the ability to take sufficiently large breaths to fuel the entire body with oxygen. According to Kent Stevens, computer-modeled reconstructions of the skeletons made from the vertebrae indicate that sauropod necks were capable of sweeping out large feeding areas without needing to move their bodies, but were unable to be retracted to

4935-418: The animal were submerged in several metres of water, the pressure would be enough to fatally collapse the lungs and airway. However, this and other early studies of sauropod ecology were flawed in that they ignored a substantial body of evidence that the bodies of sauropods were heavily permeated with air sacs . In 1878, paleontologist E.D. Cope had even referred to these structures as "floats". Beginning in

5040-401: The animal's entire back and neck. Skin fossils have been discovered at the Mother's Day Quarry that have been assigned to Diplodocus sp. These skin fossils exhibit a vast amount of scale diversity, the scales of which vary in shape, size, orientation, and 3-dimensional relief depending on their location on the integument. Some of the scale orientations may indicate where the skin originated on

5145-407: The apex forms a blunt, triangular point. The most prominent wear facet is on the apex, though unlike all other wear patterns observed within sauropods, diplodocine wear patterns are on the labial (cheek) side of both the upper and lower teeth. This implies that the feeding mechanism of Diplodocus and other diplodocids was radically different from that of other sauropods. Unilateral branch stripping

5250-405: The body. For instance, a scale orientation consisting of arching rows of square scales is noted to look similar to scale orientations seen around crocodilian limbs, so it is hypothesized that this area may have come from around a limb in life. Due to the high diversity of scales seen on a relatively small area of skin, the small size of the scales, and the presence of small and juvenile individuals at

5355-471: The center of the Bone Wars , a fossil-collecting rivalry between early paleontologists Othniel Charles Marsh and Edward Drinker Cope . In Colorado, New Mexico, and Utah, the Morrison Formation was a major source of uranium ore. According to radiometric dating , the Morrison Formation dates from 156.3 ± 2 million years old ( Ma ) at its base, to 146.8 ± 1 million years old at

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5460-523: The distance between opposite limbs: narrow gauge, medium gauge, and wide gauge. The gauge of the trackway can help determine how wide-set the limbs of various sauropods were and how this may have impacted the way they walked. A 2004 study by Day and colleagues found that a general pattern could be found among groups of advanced sauropods, with each sauropod family being characterised by certain trackway gauges. They found that most sauropods other than titanosaurs had narrow-gauge limbs, with strong impressions of

5565-649: The dominant plants of the time, were to be found with ginkgos , cycads , tree ferns , and horsetail rushes . Much of the fossilized vegetation was riparian , living along the river flood plains. Along the rivers, there were fish , frogs , salamanders , lizards , crocodiles , turtles , pterosaurs , crayfish , clams , and mammaliforms . The dinosaurs were most likely riparian, as well. Hundreds of dinosaur fossils have been discovered, such as Allosaurus , Ceratosaurus , Torvosaurus , Saurophaganax , Camptosaurus , Ornitholestes , several stegosaurs comprising at least two species of Stegosaurus and

5670-405: The end of the Jurassic and into the latest Cretaceous. Why this is remains unclear, but some similarities in feeding niches between iguanodontians, hadrosauroids and sauropods have been suggested and may have resulted in some competition. However, this cannot fully explain the full decline in distribution of sauropods, as competitive exclusion would have resulted in a much more rapid decline than what

5775-409: The end. Computer simulations have shown that the diplodocids could have easily snapped their tails, like a bullwhip . This could generate a sonic boom in excess of 200 decibels , and may have been used in mating displays, or to drive off predators. There is some circumstantial evidence supporting this as well: a number of diplodocids have been found with fused or damaged tail vertebrae , which may be

5880-423: The external claw but also completely lost the digits of the front foot. Advanced titanosaurs had no digits or digit bones, and walked only on horseshoe-shaped "stumps" made up of the columnar metacarpal bones. Print evidence from Portugal shows that, in at least some sauropods (probably brachiosaurids), the bottom and sides of the forefoot column was likely covered in small, spiny scales, which left score marks in

5985-488: The flesh miss these facts, inaccurately depicting sauropods with hooves capping the claw-less digits of the feet, or more than three claws or hooves on the hands. The proximal caudal vertebrae are extremely diagnostic for sauropods. The sauropods' most defining characteristic was their size. Even the dwarf sauropods (perhaps 5 to 6 metres, or 20 feet long) were counted among the largest animals in their ecosystem . Their only real competitors in terms of size are

6090-593: The forefeet are much smaller than the hind feet, and often crescent-shaped. Occasionally ichnites preserve traces of the claws, and help confirm which sauropod groups lost claws or even digits on their forefeet. Sauropod tracks from the Villar del Arzobispo Formation of early Berriasian age in Spain support the gregarious behaviour of the group. The tracks are possibly more similar to Sauropodichnus giganteus than any other ichnogenera, although they have been suggested to be from

6195-478: The forefeet trackways being preserved. In a study published in PLoS ONE on October 30, 2013, by Bill Sellers , Rodolfo Coria , Lee Margetts et al. , Argentinosaurus was digitally reconstructed to test its locomotion for the first time. Before the study, the most common way of estimating speed was through studying bone histology and ichnology . Commonly, studies about sauropod bone histology and speed focus on

6300-418: The forefoot bone ( metacarpal ) columns in eusauropods was semi-circular, so sauropod forefoot prints are horseshoe-shaped. Unlike elephants, print evidence shows that sauropods lacked any fleshy padding to back the front feet, making them concave. The only claw visible in most sauropods was the distinctive thumb claw (associated with digit I). Almost all sauropods had such a claw, though what purpose it served

6405-401: The gait and speed of Argentinosaurus , the study performed a musculoskeletal analysis. The only previous musculoskeletal analyses were conducted on hominoids , terror birds , and other dinosaurs . Before they could conduct the analysis, the team had to create a digital skeleton of the animal in question, show where there would be muscle layering, locate the muscles and joints, and finally find

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6510-679: The growth of sauropods, their theropod predators grew also, as shown by an Allosaurus -sized coelophysoid from Germany . Morrison Formation It is centered in Wyoming and Colorado , with outcrops in Montana , North Dakota , South Dakota , Nebraska , Kansas , the panhandles of Oklahoma and Texas , New Mexico , Arizona , Utah , and Idaho . Equivalent rocks under different names are found in Canada. It covers an area of 1.5 million square kilometers (600,000 square miles), although only

6615-447: The head in such a posture for long would have used some half of its energy intake. Further, to move blood to such a height—dismissing posited auxiliary hearts in the neck —would require a heart 15 times as large as of a similar-sized whale. The above have been used to argue that the long neck must instead have been held more or less horizontally, presumed to enable feeding on plants over a wide area with less need to move about, yielding

6720-483: The history of their study, scientists, such as Osborn , have speculated that sauropods could rear up on their hind legs, using the tail as the third 'leg' of a tripod. A skeletal mount depicting the diplodocid Barosaurus lentus rearing up on its hind legs at the American Museum of Natural History is one illustration of this hypothesis. In a 2005 paper, Rothschild and Molnar reasoned that if sauropods had adopted

6825-570: The large body mass of the sauropods has been interpreted as an adaptation to migration in times of drought. Sauropods that have been discovered include Diplodocus (most famously, the first nearly complete specimen of D. carnegii , which is now exhibited at the Carnegie Museum of Natural History , in Pittsburgh, Pennsylvania), Camarasaurus (the most commonly found sauropod), Brachiosaurus , Apatosaurus , Brontosaurus , Barosaurus ,

6930-418: The large thumb claw on the forefeet. Medium gauge trackways with claw impressions on the forefeet probably belong to brachiosaurids and other primitive titanosauriformes , which were evolving wider-set limbs but retained their claws. Primitive true titanosaurs also retained their forefoot claw but had evolved fully wide gauge limbs. Wide gauge limbs were retained by advanced titanosaurs, trackways from which show

7035-584: The largest dinosaur ever found were discovered in 2012 in the Neuquén Province of northwest Patagonia, Argentina. It is believed that they are from a titanosaur, which were amongst the largest sauropods. On or shortly before 29 March 2017 a sauropod footprint about 5.6 feet (1.7 meters) long was found at Walmadany in the Kimberley Region of Western Australia. The report said that it was the biggest known yet. In 2020 Molina-Perez and Larramendi estimated

7140-462: The long necks would have cooled the veins and arteries going to the brain, avoiding excessively heated blood from reaching the head. It was in fact found that the increase in metabolic rate resulting from the sauropods' necks was slightly more than compensated for by the extra surface area from which heat could dissipate. When sauropods were first discovered, their immense size led many scientists to compare them with modern-day whales . Most studies in

7245-583: The longest sauropods, with some species such as Supersaurus vivianae and Diplodocus hallorum estimated to have reached lengths of 30 meters (100 ft) or more. The heaviest diplodocids, such as Supersaurus and Apatosaurus , may have weighed close to 40 tonnes. However, not all diplodocids were so large; the South American species Leinkupal laticauda was one of the smallest diplodocids, with an estimated length of only 9 meters (30 ft). Their heads, like those of other sauropods, were tiny with

7350-590: The makeup of the herds varied between species. Some bone beds, for example a site from the Middle Jurassic of Argentina , appear to show herds made up of individuals of various age groups, mixing juveniles and adults. However, a number of other fossil sites and trackways indicate that many sauropod species travelled in herds segregated by age, with juveniles forming herds separate from adults. Such segregated herding strategies have been found in species such as Alamosaurus , Bellusaurus and some diplodocids . In

7455-519: The most massive were Argentinosaurus (65–80 metric tons ), Mamenchisaurus sinocanadorum (60-80 metric tons ), the giant Barosaurus specimen (60-80+ metric tons ) and Patagotitan with Puertasaurus (50-55  metric tons ). Meanwhile, 'mega-sauropods' such as Bruhathkayosaurus has long been scrutinized due to controversial debates on its validity, but recent photos re-surfacing in 2022 have legitimized it, allowing for more updated estimates that range between 110–170 tons, rivaling

7560-641: The muscle properties before finding the gait and speed. The results of the biomechanics study revealed that Argentinosaurus was mechanically competent at a top speed of 2 m/s (5 mph) given the great weight of the animal and the strain that its joints were capable of bearing. The results further revealed that much larger terrestrial vertebrates might be possible, but would require significant body remodeling and possible sufficient behavioral change to prevent joint collapse. Sauropods were gigantic descendants of surprisingly small ancestors. Basal dinosauriformes, such as Pseudolagosuchus and Marasuchus from

7665-409: The nasal openings on the top of the head (though in life the nostrils themselves would have been close to the tip of the snout). The heads of diplodocids have been widely depicted with the nostrils on top due to the position of the nasal openings at the apex of the skull. There has been speculation over whether such a configuration meant that diplodocids may have had a trunk. A 2006 study surmised there

7770-431: The neck, and the head was evolved to be very small and light, losing the ability to orally process food. By reducing their heads to simple harvesting tools that got the plants into the body, the sauropods needed less power to lift their heads, and thus were able to develop necks with less dense muscle and connective tissue. This drastically reduced the overall mass of the neck, enabling further elongation. Sauropods also had

7875-614: The occurrence of which are varied across the geographic extent of the Morrison. Members are (in alphabetical order): Other informal or disused designations of the Morrison include the Stockett Bed in Montana, an unofficial sub-unit which contains bituminous coal; the outdated terms Casamero, Chavez, and Prewitt Sandstone for the Brushy Basin, Recapture, and Westwater Canyon, respectively; and

7980-584: The point it touched the ground. Mallison concluded that diplodocids were better adapted to rearing than elephants , which do so occasionally in the wild. He also argues that stress fractures in the wild do not occur from everyday behaviour, such as feeding-related activities (contra Rothschild and Molnar). There is little agreement over how sauropods held their heads and necks, and the postures they could achieve in life. Whether sauropods' long necks could be used for browsing high trees has been questioned based on calculations suggesting that just pumping blood up to

8085-532: The postcranial skeleton, which holds many unique features, such as an enlarged process on the ulna , a wide lobe on the ilia , an inward-slanting top third of the femur , and an extremely ovoid femur shaft. Those features are useful when attempting to explain trackway patterns of graviportal animals. When studying ichnology to calculate sauropod speed, there are a few problems, such as only providing estimates for certain gaits because of preservation bias , and being subject to many more accuracy problems. To estimate

8190-642: The prints. In titanosaurs, the ends of the metacarpal bones that contacted the ground were unusually broad and squared-off, and some specimens preserve the remains of soft tissue covering this area, suggesting that the front feet were rimmed with some kind of padding in these species. Matthew Bonnan has shown that sauropod dinosaur long bones grew isometrically : that is, there was little to no change in shape as juvenile sauropods became gigantic adults. Bonnan suggested that this odd scaling pattern (most vertebrates show significant shape changes in long bones associated with increasing weight support) might be related to

8295-413: The proposal that its dentition was used for bark-stripping was not supported by the data, which showed that under that scenario, the skull and teeth would undergo extreme stresses. The hypotheses of branch-stripping and/or precision biting were both shown to be biomechanically plausible feeding behaviors. Diplodocine teeth were also continually replaced throughout their lives, usually in less than 35 days, as

8400-598: The sauropods were huge. Their giant size probably resulted from an increased growth rate made possible by tachymetabolic endothermy , a trait which evolved in sauropodomorphs. Once branched into sauropods, sauropodomorphs continued steadily to grow larger, with smaller sauropods, like the Early Jurassic Barapasaurus and Kotasaurus , evolving into even larger forms like the Middle Jurassic Mamenchisaurus and Patagosaurus . Responding to

8505-401: The scientists, the specializing of their diets helped the different herbivorous dinosaurs to coexist. Sauropod necks have been found at over 15 metres (49 ft) in length, a full six times longer than the world record giraffe neck. Enabling this were a number of essential physiological features. The dinosaurs' overall large body size and quadrupedal stance provided a stable base to support

8610-451: The shorter hind legs free of the bottom, and using the front limbs to punt forward. However, due to their body proportions, floating sauropods would also have been very unstable and maladapted for extended periods in the water. This mode of aquatic locomotion , combined with its instability, led Henderson to refer to sauropods in water as "tipsy punters". While sauropods could therefore not have been aquatic as historically depicted, there

8715-409: The sides to create a wide foot as in elephants, the manus bones of sauropods were arranged in fully vertical columns, with extremely reduced finger bones (though it is not clear if the most primitive sauropods, such as Vulcanodon and Barapasaurus , had such forefeet). The front feet were so modified in eusauropods that individual digits would not have been visible in life. The arrangement of

8820-477: The size estimates of A. fragillimus may have been highly exaggerated. The longest dinosaur known from reasonable fossils material is probably Argentinosaurus huinculensis with length estimates of 35 metres (115 ft) to 36 metres (118 ft) according to the most recent researches. However the giant Barosaurus specimen BYU 9024 might have been even larger reaching lengths of 45–48 meters (148–157 ft). The longest terrestrial animal alive today,

8925-537: The size of the animal at 31 meters (102 ft) and 72 tonnes (79.4 short tons) based on the 1.75 meter (5.7 ft) long footprint. As massive quadrupeds , sauropods developed specialized "graviportal" (weight-bearing) limbs. The hind feet were broad, and retained three claws in most species. Particularly unusual compared with other animals were the highly modified front feet ( manus ). The front feet of sauropods were very dissimilar from those of modern large quadrupeds, such as elephants . Rather than splaying out to

9030-498: The slightly older Hesperosaurus , and the early ankylosaurs , Mymoorapelta and Gargoyleosaurus , most notably a very broad range of sauropods (the giants of the Mesozoic era). Since at least some of these species are known to have nested in the area ( Camptosaurus embryoes have been discovered), there are indications that it was a good environment for dinosaurs and not just home to migratory, seasonal populations. However,

9135-583: The snout. Diplodocids had long necks, which could reach an estimated length of 15 metres (50 ft) in the largest, longest-necked species. The neck was typically composed of 15 vertebrae, though in Barosaurus , the neck probably had 16 vertebrae as the result of the incorporation of an additional vertebra from the dorsal series. The habitual neck posture of diplodocids is controversial; studies have proposed postures ranging from nearly straight and below horizontal to an S-curve that reaches vertical. A diagnosis

9240-565: The subfamily Apatosaurinae. However, a subsequent analysis by Whitlock in 2011 showed that Supersaurus is slightly closer to Diplodocus than to Apatosaurus , and that Suuwassea is actually a primitive dicraeosaurid . The subfamily Diplodocinae , was erected to include Diplodocus and its closest relatives, including Barosaurus . The Portuguese Dinheirosaurus and the African Tornieria have also been identified as close relatives of Diplodocus by some authors. Cladogram of

9345-467: The surface of the water; in other words, they would float, and would not have been in danger of lung collapse due to water pressure when swimming. Evidence for swimming in sauropods comes from fossil trackways that have occasionally been found to preserve only the forefeet (manus) impressions. Henderson showed that such trackways can be explained by sauropods with long forelimbs (such as macronarians ) floating in relatively shallow water deep enough to keep

9450-415: The tails might have been used as a tactile organ to keep in touch with the individuals behind and on the sides in a group while migrating, which could have augmented cohesion and allowed communication among individuals while limiting more energetically demanding activities like stopping to search for dispersed individuals, turning to visually check on individuals behind, or communicating vocally. Diplodocidae

9555-627: The time the earliest known dicraeosaurid, Lingwulong , appears in the fossil record. Lingwulong was originally thought to be possibly as old as Early Jurassic, but is now considered to date to the late Middle Jurassic. Most diplodocids lived during the Jurassic period, but they survived into the Early Cretaceous, at least in Africa and South America. An unnamed diplodocid is known from the Kirkwood Formation of South Africa. Leinkupal laticauda

9660-497: The time, the supercontinent of Laurasia had recently split into the continents of North America and Eurasia, although they were still connected by land bridges. North America moved north and was passing through the subtropical regions . The Morrison Basin, which stretched from New Mexico in the south to Alberta and Saskatchewan in the north, was formed during the Nevadan orogeny , a precursor event to later orogenic episodes that created

9765-434: The tip, narrow at the neck) teeth. They had tiny heads, massive bodies, and most had long tails. Their hind legs were thick, straight, and powerful, ending in club-like feet with five toes, though only the inner three (or in some cases four) bore claws. Their forelimbs were rather more slender and typically ended in pillar-like hands built for supporting weight; often only the thumb bore a claw. Many illustrations of sauropods in

9870-413: The tooth affected how long it took for a new tooth to grow. Camarasaurus 's teeth took longer to grow than those for Diplodocus because they were larger. It was also noted by D'Emic and his team that the differences between the teeth of the sauropods also indicated a difference in diet. Diplodocus ate plants low to the ground and Camarasaurus browsed leaves from top and middle branches. According to

9975-877: The top, which places it in the earliest Kimmeridgian , and early Tithonian stages of the late Jurassic. This is similar in age to the Solnhofen Limestone Formation in Germany and the Tendaguru Formation in Tanzania . The age and much of the fauna is similar to the Lourinhã Formation in Portugal. Throughout the western United States, it variously overlies the Middle Jurassic Summerville, Sundance , Bell Ranch, Wanakah, and Stump Formations. At

10080-543: The uncommon Haplocanthosaurus and Supersaurus . The very diversity of the sauropods has raised some questions about how they could all co-exist. While their body shapes are very similar (long neck, long tail, huge elephant-like body), they are assumed to have had very different feeding strategies, in order for all to have existed in the same time frame and similar environment. Locations where significant Morrison Formation fossil discoveries have been made include: The Morrison Formation contains uranium deposits, including

10185-415: The wide-set hip bones of titanosaurs ) or would have hindered rearing. For example, titanosaurs had an unusually flexible backbone, which would have decreased stability in a tripodal posture and would have put more strain on the muscles. Likewise, it is unlikely that brachiosaurids could rear up onto the hind legs, as their center of gravity was much farther forward than other sauropods, which would cause such

10290-433: The young reached adulthood. A 2014 study suggested that the time from laying the egg to the time of the hatching was likely to have been between 65 and 82 days. Exactly how segregated versus age-mixed herding varied across different groups of sauropods is unknown. Further examples of gregarious behavior will need to be discovered from more sauropod species to begin detecting possible patterns of distribution. Since early in

10395-603: Was coined by Othniel Charles Marsh in 1878, and is derived from Ancient Greek , meaning "lizard foot". Sauropods are one of the most recognizable groups of dinosaurs, and have become a fixture in popular culture due to their impressive size. Complete sauropod fossil finds are extremely rare. Many species, especially the largest, are known only from isolated and disarticulated bones. Many near-complete specimens lack heads, tail tips and limbs. Sauropods were herbivorous (plant-eating), usually quite long-necked quadrupeds (four-legged), often with spatulate (spatula-shaped: broad at

10500-426: Was discovered by Michael D'Emic et al. Within each tooth socket, as many as five replacement teeth were developing to replace the next one. Studies of the teeth also reveal that it preferred different vegetation from the other sauropods of the Morrison, such as Camarasaurus . This may have better allowed the various species of sauropods to exist without competition. Long-bone histology enables researchers to estimate

10605-400: Was no paleoneuroanatomical evidence for a trunk. It noted that the facial nerve in an animal with a trunk, such as an elephant, is large as it innervates the trunk. The evidence suggests that the facial nerve is very small in diplodocids. Studies by Lawrence Witmer (2001) indicated that, while the nasal openings were high on the head, the actual, fleshy nostrils were situated much lower down on

10710-892: Was recognized early in the study of these animals, and, in fact, at least one sauropod specimen found in the 19th century ( Ornithopsis ) was originally misidentified as a pterosaur (a flying reptile) because of this. Some sauropods had armor . There were genera with small clubs on their tails, a prominent example being Shunosaurus , and several titanosaurs , such as Saltasaurus and Ampelosaurus , had small bony osteoderms covering portions of their bodies. A study by Michael D'Emic and his colleagues from Stony Brook University found that sauropods evolved high tooth replacement rates to keep up with their large appetites. The study suggested that Nigersaurus , for example, replaced each tooth every 14 days, Camarasaurus replaced each tooth every 62 days, and Diplodocus replaced each tooth once every 35 days. The scientists found qualities of

10815-570: Was reported by Stephen Czerkas in 1992. Fossils from the Howe Quarry in Shell, Wyoming preserved portions of the skin from around the tip of the tail, or "whiplash". Czerkas noted that the skin preserved a sequence of conical spines, and that other, larger spines were found scattered around larger tail vertebrae. The spines appeared to be oriented in a single row along the mid-line of the tail, and Czerkas speculated that this midline row may have continued over

10920-442: Was the longest sauropod known from reasonably complete remains, but others, like the old record holder, Diplodocus , were also extremely long. The holotype (and now lost) vertebra of Amphicoelias fragillimus (now Maraapunisaurus ) may have come from an animal 58 metres (190 ft) long; its vertebral column would have been substantially longer than that of the blue whale. However, research published in 2015 speculated that

11025-422: Was the third name given to what is now recognized as the single family of long-necked, whip-tailed sauropods. Edward Drinker Cope named the family Amphicoeliidae in 1878 for his genus Amphicoelias , sometimes considered a diplodocid. However, the name Amphicoeliidae did not come into wider use and was not used in the scientific literature after 1899, making it a nomen oblitum ("forgotten name") according to

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