Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct clade of saurischian dinosaurs that includes the long-necked, herbivorous sauropods and their ancestral relatives. Early, more basal sauropodomorphs (traditionally termed prosauropods) were bipedal, and the earliest show evidence of omnivorous or carnivorous diets. Over time, sauropodomorph evolution resulted in a shift to herbivorous diets, larger body sizes, and quadrupedal locomotion. The sauropods themselves generally grew to very large sizes, had long necks and tails, and became the largest animals to ever walk the Earth. The sauropods were the dominant terrestrial herbivores throughout much of the Mesozoic Era, from their origins in the Late Triassic (approximately 230 Ma) until their decline and extinction at the end of the Cretaceous.
History of study
Early study
Gigantic bones of sauropods have been known for thousands of years and become part of legends and cultures but the beginning of their scientific study was in the 1830s. which is about twice the size of the related Yunnanosaurus, which is known from more complete remains and weighed about 3 tons. However, there is a large but relatively incomplete sauropodomorph (specimen BP/1/5339) discovered in South Africa that has not yet been fully described. Andrew Yates and Matthew Wedel have suggested that the morphology of its arm bones meant it was probably an obligate biped. Scaling based on the sympatric genus Aardonyx and femur allometry, this bipedal sauropodomorph would have had mass between 10-15 tons, making it comparable in size to Diplodocus and possibly one of the largest bipedal animals ever.
thumb|Size diagram of Vulcanodon, one of the earliest sauropodomorphs to have columnar limbs
The evolution of obligatory quadrupedality enabled the true sauropods and their closest relatives to achieve very large sizes. The oldest confidently quadrupedal sauropodomorph, Melanorosaurus is not known from very complete remains, and Paul Barrett and Jonah Choiniere declined to suggest a mass estimate in their osteology of Melanorosaurus published in 2024. However, Gregory S. Paul estimated Melanorosaurus to have been about long and weighed around a ton, which is comparable to many bipedal sauropodomorphs. By the end of the Triassic, the 7 ton Lessemsaurus had evolved, marking the origin of the oldest true sauropods. The early Jurassic saw the evolution of the even larger Ledumahadi, which weighed around 12 tons.
The final anatomical bottleneck on the size of the true sauropods was the anatomy of their limbs. Columnar limbs evolved at some point in the early Jurassic. The oldest sauropod known to have had columnar limbs was Vulcanodon, which lived in what is now Zimbabwe around 199-188 million years ago. Earlier sauropods may have had columnar limbs, but their remains are too incomplete to determine if this is the case. Vulcanodon has been estimated to have had mass up to 10 tons, making it one of the largest terrestrial animals of its time. True gigantism emerged at the beginning of the Late Jurassic; genera like Turiasaurus and Mamenchisaurus were up to long and may have had masses up to 30 tons. During the Late Jurassic and throughout the Cretaceous Period, true gigantism evolved independently several times in distantly related sauropod groups. Giants like Brachiosaurus, Dreadnoughtus, and Ruyangosaurus are believed to have exceeded in length and had masses in excess of 50 tons, making them the largest land animals of all time. Higher mass estimates have been made for very poorly-known taxa such as Maraapunisaurus and Bruhathkayosaurus, but these remain controversial.
thumb|left|Several of the largest sauropods compared in size to a human
Sauropods reached a variety of different body proportions, so the "largest" individual species will vary based on the measurement concerned. The longest known sauropod was probably Supersaurus, which may have exceeded in length. The tallest sauropodomorph was probably Sauroposeidon, which had a relatively erect posture and may have been able to reach a height of between . The longest neck of any sauropod known from complete remains is that of Xinjiangtitan, which had a neck meters long. Very large isolated cervical vertebrae from taxa like Hudiesaurus and Mamenchisaurus have been found, but the incompleteness of these remains makes it difficult to assess the total length of their necks. The most massive sauropodomorph known from relatively complete remains is generally accepted to be Argentinosaurus, which may have exceeded 70 tons in mass. Sauropods were generally much larger, but several sauropods are believed to have been examples of insular dwarfism. Magyarosaurus, Europasaurus, and Petrustitan are the smallest sauropods known from adult remains; they were between long and had mass less than a ton. Other small sauropods existed throughout the Mesozoic including Haplocanthosaurus, Bonatitan, and Ohmdenosaurus, which were each between 1-2 tons. It was not until the diversification of the true sauropods that a wider variety of skull dimensions evolved. Wide and robust skulls evolved on multiple occasions within Sauropoda. The rebbachisaurid Nigersaurus had a relatively wide skull, and similarly wide and robust skulls evolved in Camarasauridae, Brachiosauridae, Euhelopodidae, and other somphospondylans. More basal sauropods, like Shunosaurus, Mamenchisaurus, and members of Diplodocidae, retained relatively narrow and lightly built skulls. However, the study of these trends is complicated by the relative rarity of sauropod skulls in the fossil record.
thumb|left|The skull of Plateosaurus, an archetypal "prosauropod"
The evolution of basal sauropodiformes (called "near-sauropods" by some sources)
Some uncertainties remain regarding the evolution of soft tissue anatomy in sauropodomorphs. Some prosauropods skulls have been suggested to preserve osteological correlates associated with cheeks, but true sauropods are generally believed to have lacked cheeks. When this transition occurred remains an unanswered question. Uniquely, some of the features on the maxillae of Riojasaurus suggest that it may have had a rhamphotheca. This elongation coincided with a shrinking of the skull, probably to reduce the muscular strain on the neck that a large head would create.
The elongation of sauropodomorph necks is suggested to have provided a comparative advantage versus other large herbivores such as aetosaurs and dicynodonts in allowing them to feed on a wider variety of vegetation. This process of neck elongation closely mirrored the evolution of sauropodomorph teeth, which saw a trend towards adaptations for herbivory during this same interval.
The evolution of long necks required a suite of adaptations to sauropodomorph vertebrae. A long neck is necessarily more massive than a short neck, and therefore the evolution of long necks coincided with the development of broad cervical vertebrae to accommodate the expansion of neck muscles. Primitive sauropodomorphs with short necks had weak and small or no . These features of the vertebrae grew broad in sauropodomorphs with longer necks and likely served as attachment sites for large trapezius muscles. These expanded muscles were necessary for sauropodomorphs to hold their necks and heads up, and the presence of large trapezii is also supported by broad muscle attachment sites on the shoulders of these taxa. The evolution of true sauropods saw an increase in the development of broad and robust cervical vertebrae to facilitate the evolution of increasingly long and massive necks.
Skeletal pneumaticity
thumb|left|Diagram showing the evolution of invasive air sacs in sauropodomorphs
Sauropodomorphs possessed a system of air sacs throughout their body which were connected to the respiratory system. During development, these air sacs expanded via branching structures called "diverticula" (singular "diverticulum") which invaded and carved holes into parts of the skeleton. These invasive diverticula formed structures called pleurocoels and pneumatic fossae, which are preserved in the fossils and can be used by researchers to infer the presence of these air sacs. These adaptations are also seen in birds, non-avian theropods, and pterosaurs, but are completely absent in ornithischians. This has led to the suggestion that pneumatic skeletons are ancestral to bird-line archosaurs and were secondarily lost in ornithischians. However, an analysis of the skeletons of three dinosaurs including two sauropodomorphs (Buriolestes, Gnathovorax, and Pampadromaeus) conducted in 2022 found that none of the taxa studied possessed signs of an invasive air-sac system in their vertebrae. This led the authors of the study to the conclusion that this respiratory apparatus evolved independently in pterosaurs, theropods, and sauropodomorphs.
An important genus in the study of pneumaticity in early sauropodomorphs is Macrocollum, from the Triassic of Brazil. It is one of the earliest sauropodomorphs to achieve sizes larger than , and the skeletal remains of the genus also preserve some of the oldest evidence of pneumatic vertebrae in this group. Earlier taxa are either fully apneumatic (lacking invasive air sacs) or with only very minor pneumaticity, but Macrocollum possessed signs of an invasive air sac system in both the lower cervical vertebrae and upper dorsal vertebrae. It is notable however that the evolution of vertebral pneumaticity in sauropodomorphs was not a linear process. Taxa that evolved after Macrocollum including Plateosaurus possessed invasive pneumaticity in the cervical vertebrae, but seemed to lack this adaptation in the dorsal vertebrae. The Early Jurassic genus Aardonyx had an extensive air sac system in the lower dorsal vertebrae and sacrum, but had entirely apneumatic cervical vertebrae. It appears that extensive pneumaticity along the entire vertebral column did not become established until the evolution of the true sauropods. The exact locations of pneumatic elements on the bones are highly variable even within taxa, which is a consequence of these elements developing in tandem with the circulatory system, rather than the development of the skeleton itself.
thumb|The tail bones of [[Apatosaurus, with the pneumatic fossae clearly visible]]
The researchers Matt Taylor and Mike Weddel have written extensively about variation in the invasive air sac systems of sauropodomorphs. Weddel conducted a general review of sauropodomorph skeletal pneumaticity in 2007 which surmised that the ribs and vertebrae of prosauropods were generally much less extensively pneumatized than those of the true sauropods. Some prosauropods, including Pantydraco (then called Thecodontosaurus caudus) possessed excavations in their cervical vertebrae which were described as "pleurocoel-like", but may or may not have been true pleurocoels created by pneumatic diverticula. Other vertebral structures indicative of pneumaticity in true sauropods (laminae and fossae on the vertebrae) are present in various prosauropods such as Plateosaurus and Pantydraco, but these are not interpreted as signs of true pneumaticity because the texture of the bone associated with these structures generally does not differ from fully apneumatic bone. Similar laminae and fossae are present in a variety of other archosaurs including pseudosuchians (which do not have any pneumatic elements in the skeleton), which may indicate that these structures are ancestral to archosaurs and evolved independently of an invasive air sac system.
Skeletal pneumaticity may also have evolutionary benefits in lightening the skeleton. The invasive air sacs made the bones as a whole less-dense, allowing them to increase in size without having to invest the same volume of resources as if the bones were completely solid. This may have been a contributing factor in allowing sauropodomorphs to evolve large sizes in such a short time.
Arms and claws
thumb|left|Hand bones of Plateosaurus, showing the enlarged claw on the first finger
Like all dinosaurs, sauropodomorphs evolved from bipedal ancestors with five digits on each hand. They did not however possess claws on all of their digits. Early sauropodomorphs only had claws on the first three digits (sometimes called the "thumb"), and their early evolution was marked by an increase in the size of the first digit and its associated claw. As the transition to quadrupedality took place throughout the Triassic and into the Jurassic, the claws on the second and third digits reduced in size and disappeared. However, even into the Late Cretaceous, large sauropods retained a large claw on the first digit of the hand. Range of motion for the forelimbs changed considerably during the course of sauropodomorph evolution. A more derived prosauropod, Mussaurus (which was also bipedal) was likely able to pronate its arms to some degree, and the mobility of its elbow joint was likely much greater than in earlier prosauropods. This was a precursor to the evolution of the fuller pronation which was necessary for quadrupedality to evolve.
The size of the arms relative to the body in sauropodomorphs increased generally during their early evolution. Even fully bipedal taxa like Aardonyx had arms which were similar in length to their hind legs. This saw its culmination with the evolution of Melanorosaurus and the true sauropods, which were believed to have been an obligate quadrupeds and would have used their limbs more exclusively for locomotion. However, even in the largest Early Jurassic sauropodomorphs, such as Ledumahadi, the forelimbs were not fully columnar, and they still retained a degree of mobility in their elbows and wrists that would have been impossible for the true sauropods. A study by Griebeler et al. (2013) concluded that the maximum growth rates of sauropodomorphs were comparable to those of precocial birds and the black rhinoceros but lower than the growth rates of average mammals.
For the taxa which had published mass estimates (Buriolestes, Macrocollum, Diplodocus, Camarasaurus, and Nigersaurus), Müller compared these ORs to their total body mass, and these relationships were in turn compared to the OR-to-body-mass ratios for theropods and ornithischians. He found that Butiolestes, Macrocollum, and Camarasaurus had very high OR-to-body-mass ratios compared to most of the other dinosaurs sampled. This suggests that smell was an important sense for a wide variety of sauropodomorph taxa regardless of absolute body size. The earliest sauropodomorph taxa are believed to have been carnivores, and smell likely served a predatory function in taxa like Buriolestes. However, the continued prevalence of the olfactory bulbs in fully herbivorous taxa suggests that it remained important for other reasons. Suggested functions include distinguishing edible plants from inedible plants, detecting predators, or using smell in social interactions.
The hearing abilities of sauropodomorphs have not been the subject of extensive study. Michael Hanson and colleagues published a study of reptile inner ear morphology in 2021 in which they examined the bony ear structure of numerous reptiles including the sauropodomorph Thecodontosaurus. Archosaur cochlear shape elongated in a relatively linear fashion on the line towards birds, which was suggested by Hanson and colleagues to be a paedomorphic adaptation to hear the high-pitched vocalizations of juveniles of the same species. This line of evidence is also used to suggest that parental care evolved early in the evolution of archosaurs, and therefore would have been present in sauropodomorphs. The high-pitched calls of juvenile sauropodomorphs would have been distinct and differentiable to the parents' ears from other ambient noise. Thecodontosaurus fit into the general category that Hanson and colleagues called "Semicircular Canal Morphotype 2", with dimensions similar to other non-avian dinosaurs and palaeognaths, suggesting the general hearing capabilities of these groups were broadly similar.
Diet and digestion
Sauropodomorphs exhibited a wide variety of diets over the 160 million years during which they existed. Sauropodomorphs are believed to have been ancestrally carnivorous, with later genera evolving to be omnivorous. The largest prosauropods and the true sauropods are believed to have been the first group of dinosaurs to become fully herbivorous, with this dietary shift contributing to their general increase in body size.
Throughout the course of their evolution, sauropodomorphs never evolved the ability to chew. Scientists have inferred this from the relatively simple jaw joints they possessed. Chewing requires a relatively complex jaw morphology to allow the jaws to flex along multiple planes of motion in order to achieve the grinding action that makes chewing possible, and no sauropodomorph skulls appear to preserve the ability to perform this range of motion. This inability to chew distinguishes sauropodomorphs from large herbivorous mammals and also from the large herbivorous ornithischians with which they coexisted. Some scientists have suggested that the long necks of sauropodomorphs imposed constraints on the evolution of their heads which prevented the robust jaws and musculature necessary to evolve the ability to chew. Over the course of their evolution, sauropodomorphs evolved other methods of assisting with the digestion of large amounts of plant matter. Gastroliths can be difficult to distinguish from other rocks in the fossil record, but they are generally smooth and relatively uniform in size within a single animal. The presence of gastroliths in sauropodomorphs had evolved by the Early Jurassic because several taxa including Massospondylus and Ammosaurus (possibly a junior synonym of Anchisaurus) have been found with stones preserved inside their body cavities that are believed to be gastroliths. However, this adaptation was not necessarily widespread among prosauropods. Members of Plateosauridae are well represented in the fossil record—being known from hundreds of specimens—but there are few unambiguous examples of gastroliths preserved in these fossils. Some authors have suggested that the use of gastroliths did not become widespread until after the common ancestor of Massospondylidae and Sauropoda had already diverged from their common ancestor with Plateosauridae.
Metabolism and thermoregulation
thumb|left|The basal sauropodomorph [[Pampadromaeus, here depicted with a speculative coat of feathers]]
Metabolic strategies in extant animals are quite varied and cannot be neatly categorized. The general distinction between ectothermy ("cold-bloodedness") and endothermy ("warm-bloodedness") is based on the dramatic metabolic differences between extant mammals and birds (which have very high metabolic rates) and modern reptiles, which have very slow metabolic rates by comparison. Some researchers have suggested that this simple dichotomy does not account for the full range of possible variation, especially in the fossil record, because they both represent derived metabolic conditions. Archosaurs (and possibly amniotes more generally) may have had significantly higher metabolic rates than modern crocodilians and squamates—a metabolic condition which is sometimes called mesothermy. It is unclear when the avian metabolic condition evolved, but it is believed to have been present in most theropods based on histological data.
The presence of feathers is often used as a proxy measure of an endothermic metabolism. Pterosaurs, theropods, and ornithischians are all known to have possessed feathers or feather-like filaments, which has led some researchers to suggest that feathers may have been an ancestral trait for bird-line archosaurs. If this is true, it would imply that sauropodomorphs were ancestrally feathered, which itself may have implied an endothermic (or at least moderately high) metabolism. However, researchers who have studied the question concluded that it is not likely, given the current evidence, that feathers were an ancestral trait for bird-line archosaurs, and it is more probable that feathers or filaments evolved independently in pterosaurs, theropods, and ornithischians. This implies that sauropodomorphs were ancestrally scaly.
thumb|Evolutionary regimes along the temperature axis (in degrees C) are shown for Sauropodomorpha
Other proxies for metabolism in sauropodomorphs include inferences based on their paleobiogeography. Palynology and other plant fossils can be used to infer climatic data for various paleoenvironments in which sauropodomorphs were present. Global sampling of fossil data indicates that sauropodomorphs generally were more common at lower latitudes, which may be indicative of lower metabolic rates and a higher reliance on environmental conditions to maintain a high internal temperature. However, this correlation may also be non-causal because plant matter is also generally more abundant in lower latitudes and sauropodomorphs (due to their generally large size) would have needed much more plant matter to sustain their size regardless of their metabolic proclivities. This apparent sauropodomorph preference for lower latitudes could also reflect a sampling bias in the fossil record, and should not necessarily be interpreted as indicative of anything by itself. Some researchers have also used regression analyses of metabolic rates in extant vertebrates based on body mass to estimate that most dinosaurs, including sauropodomorphs, were mesotherms.
Some researchers have suggested that it would be impossible for animals as large as sauropods to exhibit endothermy because they were too large and would overheat. This was subsequently called into question by Eva Maria Griebeler, who used data from extant animals and from dinosaurs with known ontogenetic series and published mass estimates to approximate the internal temperatures of dinosaurs at various points in their lives. While her findings were not meant to determine precise body temperature estimates, she did find that the body temperature of large dinosaurs did not scale directly with their size beyond a certain mass, meaning that endothermic sauropods would not necessarily overheat. This finding did not conclusively determine whether or not sauropodomorphs were endotherms, but it did disprove the overheating hypothesis. Other authors have examined the skull vasculature of sauropods and found that the large present in most sauropod genera could have served as efficient sites for heat exchange. This meant that the brains of sauropods could be kept cooler than the rest of the body, and this temperature differential could have allowed for higher body temperatures to be non-lethal. Some researchers have also suggested a thermoregulatory role for the respiratory air sacs, but other researchers have dismissed these as lacking sufficient evidence.
Gait and locomotion
The early evolution of saurodomorphs was marked by a change in leg proportions away from the cursorial adaptations which characterized basal genera like Buriolestes and Pampadromaeus. The first sauropodomorphs to achieve larger body sizes had already shifted away from this locomotor style — change which would only compound throughout the Triassic. The prosauropod Massospondylus is also known from embryos, which have relatively long arms, similar to those of the embryos of Mussaurus. Suggestions of quadrupedality in young Massospondylus is complicated by the much simpler wrist anatomy of the taxon, which would have made wrist pronation impossible. However, trace fossils from the same locality as the Massospondylus embryos show clear evidence of quadrupedal locomotion, with hand imprints clearly distinct from footprints. These handprints show that the hands were rotated outwards (thus unpronated), suggesting that quadrupedality as a feature of prosauropod juveniles significantly predated the evolution of complex wrists.
It is not clear how many times quadrupedal locomotion evolved independently among adult sauropodomorphs, but Kimberly Chapelle and colleagues suggested in 2020 that this happened at least twice. The first of these occurrences would have been some time after the diversification of Massopoda but before the evolution of Mussaurus. This hypothesis implies that non-sauropod sauropodiformes like Anchisaurus and Riojasaurus were quadrupedal. At some point, bipedality re-evolved in taxa like Mussaurus and Yunnanosaurus, and then quadrupedality re-evolved at some point around the evolution of Melanorosaurus and Lessemsauridae. is a junior synonym of Plateosauridae as both contain the same taxa.
The phylogenetic analysis of Otero et al., 2015 found Sauropodomorpha to be in a polytomy with Agnosphitys and Theropoda within Eusaurischia, with Herrerasauridae and Eoraptor external to it within Saurischia. A large phylogenetic analysis of early dinosaurs published by Matthew Baron, David Norman and Paul Barrett (2017) in the journal Nature redefined Sauropodomorpha and Saurischia and recovered Herrerasauridae as the sister group to Sauropodomorpha within Saurischia. This resulted from the proposed removal of Theropoda from Saurischia and the formation of Ornithoscelida, a clade containing Theropoda and Ornithischia.
Phylogeny
Within Sauropodomorpha, there is a large clade named Plateosauria. The name Plateosauria was first coined by Gustav Tornier in 1913. The name afterwards fell out of use until the 1980s. Plateosauria is a node-based taxon. In 1998, Paul Sereno defined Plateosauria as the last common ancestor of Plateosaurus engelhardti and Massospondylus carinatus, and its descendants.
However, recent cladistic analyses suggest that the Prosauropoda as traditionally defined is paraphyletic to sauropods. Prosauropoda, as currently defined, is a synonym of Plateosauridae as both contain the same taxa by definition. The phylogenetic analysis of 2021 recovered Issi and Plateosaurus as the basal-most plateosaurs. Below is a cladogram of basal sauropodomorpha after Apaldetti and colleagues, 2021.
Massopoda is a clade of sauropodomorph dinosaurs within Sauropodomorpha which lived during the Late Triassic to Late Cretaceous epochs. 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. Sauropodiformes is a more exclusive stem-based clade within Massopoda, defined as "the most inclusive clade containing Saltasaurus but not Massospondylus".
Subgroups
Below are the various subgroups of sauropodomorphs alongside their accompanying definitions.
{| class="wikitable sortable" align="center" width="100%"
! Name
! Named by
! Definition
! Notes
|-
| Anchisauria
| Galton & Upchurch, 2004
| Least inclusive clade containing both Anchisaurus and Melanorosaurus
|
|-
| Eusauropoda
| Upchurch, 1995
| Least inclusive clade containing both Shunosaurus and Saltasaurus
|
|-
| Prosauropoda
| Huene, 1920
| Most inclusive clade containing Plateosaurus but not Saltasaurus
| Phylogenetic definition given by Sereno in 2005, this definition may be synonymous with Plateosauridae
|-
| Sauropoda
| Marsh, 1878
| Most inclusive clade containing Saltasaurus but not Melanorosaurus;
| Alternative definitions given by Yates, 2007 and Langer et al., 2010,
|-
| Sauropodiformes
| Sereno, 2007
| Least inclusive clade containing Mussaurus and Saltasaurus
|-
| Sauropodomorpha
| Huene, 1932
| Most inclusive clade containing Diplodocus but not Triceratops; about 230 million years ago (Mya), they became the dominant herbivores by halfway through the late Triassic (during the Norian stage). Their perceived decline in the early Cretaceous is most likely a bias in fossil sampling, as most fossils are known from Europe and North America, but sauropods were still the dominant herbivores in the Gondwanan landmasses. The spread of flowering plants (angiosperms) and "advanced" ornithischians, another major group of herbivorous dinosaurs (noted for their highly developed chewing mechanisms), are most likely not a major factor in sauropod decline in the northern continents. Like all non-avian dinosaurs (birds), the sauropodomorphs became extinct 66 Mya, during the Cretaceous–Paleogene extinction event.
The earliest and most basal sauropodomorphs known are Chromogisaurus novasi and Panphagia protos, both from the Ischigualasto Formation, dated to 231.4 million years ago (late Carnian age of the Late Triassic according to the ICS). Some studies have found Eoraptor lunensis (also from the Ischigualasto Formation), traditionally considered a theropod, to be an early member of the sauropodomorph lineage, which would make it the most basal sauropodomorph known.
Sauropodomorph remains have been found on every continent, including Antarctica. They evolved during the existence of the supercontinent Pangaea, and are believed to have been widespread on this landmass prior to its separation into multiple continents. However, multiple intercontinental dispersal events are believed to have occurred after Pangaea began to separate, resulting in the widespread proliferation of true sauropods after they evolved. Sauropods themselves are also known from every continent, including Antarctica.
Timeline of groups
<timeline>
ImageSize = width:950px height:auto barincrement:15px
PlotArea = left:10px bottom:50px top:10px right:10px
Period = from:-251 till:-48
TimeAxis = orientation:horizontal
ScaleMajor = unit:year increment:10 start:-251
ScaleMinor = unit:year increment:1 start:-251
TimeAxis = orientation:hor
AlignBars = justify
Colors =
- legends
id:SMP value:green
id:SAU value:blue
id:black value:black
id:white value:white
id:mesozoic value:rgb(0.54,0.54,0.258)
id:triassic value:rgb(0.51,0.17,0.57)
id:earlytriassic value:rgb(0.6,0.22,0.61)
id:middletriassic value:rgb(0.73,0.53,0.71)
id:latetriassic value:rgb(0.78,0.65,0.8)
id:jurassic value:rgb(0.2,0.7,0.79)
id:earlyjurassic value:rgb(0,0.69,0.89)
id:middlejurassic value:rgb(0.52,0.81,0.91)
id:latejurassic value:rgb(0.74,0.89,0.97)
id:cretaceous value:rgb(0.5,0.78,0.31)
id:earlycretaceous value:rgb(0.63,0.78,0.65)
id:latecretaceous value:rgb(0.74,0.82,0.37)
id:paleogene value:rgb(0.99,0.6,0.32)
id:paleocene value:rgb(0.99,0.65,0.37)
id:eocene value:rgb(0.99,0.71,0.42)
BarData=
bar:eratop
bar:space
bar:periodtop
bar:space
bar:NAM1
bar:NAM2
bar:NAM3
bar:NAM4
bar:NAM5
bar:NAM6
bar:NAM7
bar:NAM8
bar:NAM9
bar:NAM10
bar:NAM11
bar:NAM12
bar:NAM13
bar:NAM14
bar:space
bar:period
bar:space
bar:era
PlotData=
align:center textcolor:black fontsize:M mark:(line,black) width:25
shift:(7,-4)
bar:periodtop
from: -251 till: -245 color:earlytriassic text:Early
from: -245 till: -228 color:middletriassic text:Middle
from: -228 till: -199.6 color:latetriassic text:Late
from: -199.6 till: -175.6 color:earlyjurassic text:Early
from: -175.6 till: -161.2 color:middlejurassic text:Middle
from: -161.2 till: -145.5 color:latejurassic text:Late
from: -145.5 till: -99.6 color:earlycretaceous text:Early
from: -99.6 till: -65.5 color:latecretaceous text:Late
from: -65.5 till: -55.8 color:paleocene text:Pal.
from: -55.8 till: -48 color:Eocene text:Eo.
bar:eratop
from: -251 till: -199.6 color:triassic text:Triassic
from: -199.6 till: -145.5 color:jurassic text:Jurassic
from: -145.5 till: -65.5 color:cretaceous text:Cretaceous
from: -65.5 till: -48 color:paleogene text:Paleogene
PlotData=
align:left fontsize:M mark:(line,white) width:5 anchor:till align:left
color:SMP bar:NAM1 from:-233.3 till:-201 text:Primitive sauropodomorphs
color:SMP bar:NAM3 from:-225 till:-190 text:Plateosauridae
color:SMP bar:NAM5 from:-227 till:-176 text:Massospondylidae
color:SMP bar:NAM7 from:-216 till:-185 text:Non-sauropod sauropodiformes
color:SAU bar:NAM9 from:-206 till:-167 text:Primitive sauropods
color:SAU bar:NAM11 from:-184 till:-114 text:Non-neosauropod eusauropods
color:SAU bar:NAM13 from:-168 till:-65.5 text:Neosauropods
PlotData=
align:center textcolor:black fontsize:M mark:(line,black) width:25
bar:period
from: -251 till: -245 color:earlytriassic text:Early
from: -245 till: -228 color:middletriassic text:Middle
from: -228 till: -199.6 color:latetriassic text:Late
from: -199.6 till: -175.6 color:earlyjurassic text:Early
from: -175.6 till: -161.2 color:middlejurassic text:Middle
from: -161.2 till: -145.5 color:latejurassic text:Late
from: -145.5 till: -99.6 color:earlycretaceous text:Early
from: -99.6 till: -65.5 color:latecretaceous text:Late
from: -65.5 till: -55.8 color:paleocene text:Pal.
from: -55.8 till: -48 color:Eocene text:Eo.
bar:era
from: -251 till: -199.6 color:triassic text:Triassic
from: -199.6 till: -145.5 color:jurassic text:Jurassic
from: -145.5 till: -65.5 color:cretaceous text:Cretaceous
from: -65.5 till: -48 color:paleogene text:Paleogene
</timeline>
References
</references>
External links
- Sauropodomorpha: Overview, from Palæos.
- Sauropodmorpha , from When Dinosaurs Ruled Texas, by Jon A. Baskin.
- Geol 104 Dinosaurs: A natural history: Sauropodomorpha: Size matters, by Thomas R. Holtz Jr., from the University of Maryland.