Quadrupedalism is a form of locomotion where animals have four legs that are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four legs is said to be a quadruped (from Latin quattuor for "four", and pes , pedis for "foot"). Quadruped animals are found among both vertebrates and invertebrates .
25-836: The Melanorosauridae were a family of sauropodomorph dinosaurs which lived during the Late Triassic and Early Jurassic . The name Melanorosauridae was first coined by Friedrich von Huene in 1929. Huene assigned several families of dinosaurs to the infraorder " Prosauropoda ": the Anchisauridae , the Plateosauridae , the Thecodontosauridae , and the Melanorosauridae. Since then, these families have undergone numerous revisions. Galton and Upchurch (2004) considered Camelotia , Lessemsaurus , and Melanorosaurus members of
50-407: A four-legged graviportal gait adapted only to walking slowly on land, like elephants. The early sauropodomorphs were most likely omnivores as their shared common ancestor with the other saurischian lineage (the theropods ) was a carnivore . Therefore, their evolution to herbivory went hand in hand with their increasing size and neck length. They also had large nostrils (nares), and retained
75-431: A light, tiny skull on the end of a long neck (with ten or more elongated cervical vertebrae ) and a counterbalancing long tail (with one to three extra sacral vertebrae). Their teeth were weak, and shaped like leaves or spoons (lanceolate or spatulate). Instead of grinding teeth, they had stomach stones ( gastroliths ), similar to the gizzard stones of birds and crocodiles, to help digest tough plant fibers. The front of
100-530: 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
125-492: A number of characteristics with the Ornithischia , so a small minority of palaeontologists , like Bakker , have historically placed both sets of herbivores within a group called "Phytodinosauria" or "Ornithischiformes". In Linnaean taxonomy , Sauropodomorpha (which means "lizard feet forms") is either a suborder or is left unranked. It was originally established by Friedrich von Huene in 1932, who broke it into two groups:
150-466: A thumb (pollex) with a big claw, which may have been used for defense — though their primary defensive adaptation was their extreme size. Sauropodomorphs can be distinguished as a group on the basis of some of the following synapomorphies : Among the first dinosaurs to evolve in the Late Triassic period, about 230 million years ago (Mya), they became the dominant herbivores by halfway through
175-521: 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. Cladogram after Novas et al., 2011: Unnamed form. Fossil ISI R277 Panphagia Guaibasaurus Chromogisaurus Saturnalia Pantydraco Thecodontosaurus Nambalia Efraasia Plateosauravus Ruehleia Plateosauridae Riojasauridae Anchisauria Massospondylidae Below
200-499: Is a cladogram of basal sauropodomorpha after Müller, 2019. Buriolestes Eoraptor Chromogisaurus Pampadromaeus Panphagia Saturnalia Bagualosaurus ISI R277 Nambalia Arcusaurus Pantydraco Thecodontosaurus Plateosauravus Ruehleia Efraasia Plateosaurus Quadruped Although the words ‘quadruped’ and ‘tetrapod’ are both derived from terms meaning ‘four-footed’, they have distinct meanings. A tetrapod
225-430: Is a junior synonym of Plateosauridae as both contain the same taxa. Most modern classification schemes break the prosauropods into a half-dozen groups that evolved separately from one common lineage. While they have a number of shared characteristics, the evolutionary requirements for giraffe-like browsing high in the trees may have caused convergent evolution , where similar traits evolve separately because they faced
250-463: Is an extinct clade of long-necked, herbivorous , saurischian dinosaurs that includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had long necks and tails, were quadrupedal , and became the largest animals to ever walk the Earth. The prosauropods , which preceded the sauropods, were smaller and were often able to walk on two legs. The sauropodomorphs were
275-407: Is any member of the taxonomic unit Tetrapoda (which is defined by descent from a specific four-limbed ancestor), whereas a quadruped actually uses four limbs for locomotion. Not all tetrapods are quadrupeds and not all entities that could be described as ‘quadrupedal’ are tetrapods. This last meaning includes certain artificial objects; almost all quadruped organisms are tetrapods (one exception
SECTION 10
#1732868683518300-491: Is some raptorial arthropods adapted for four-footed locomotion, such as the Mantodea . Another example is brush-footed butterflies (Nymphalidae), the largest butterfly family with ~6000 species, including the well-known monarch (shown in photo). The distinction between quadrupeds and tetrapods is important in evolutionary biology , particularly in the context of tetrapods whose limbs have adapted to other roles (e.g., hands in
325-700: 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. Sauropodomorpha is one of the two major clades within the order Saurischia . The sauropodomorphs' sister group, the Theropoda , includes bipedal carnivores like Velociraptor and Tyrannosaurus ; as well as birds. However, sauropodomorphs also share
350-571: The Plateosauria belonged to the Prosauropoda, and included the Plateosauridae subgroup. In Galton's and Upchurch's study also Coloradisaurus , Euskelosaurus , Jingshanosaurus , Massospondylus , Mussaurus , Sellosaurus , and Yunnanosaurus proved to be plateosaurians. However, recent cladistic analyses suggest that the Prosauropoda as traditionally defined is paraphyletic to sauropods . Prosauropoda, as currently defined,
375-504: The basal forms within Prosauropoda , and their descendants, the giant Sauropoda . Phylogenetic analyses by Adam Yates (2004, 2006) and others firmly placed Sauropoda within a paraphyletic "Prosauropoda". Recent cladistic analyses suggest that the clade Prosauropoda , which was named by Huene in 1920 and was defined by Sereno, in 1998, as all animals more closely related to Plateosaurus engelhardti than to Saltasaurus loricatus ,
400-415: The case of humans, wings in the case of birds and bats, and fins in the case of whales). All of these animals are tetrapods, but not all are quadrupeds. Even snakes, whose limbs have become vestigial or lost entirely, are, nevertheless, tetrapods. Quadrupedalism is sometimes referred to as being "on all fours", and is observed in crawling , especially by infants. In the 20th century quadrupedal movement
425-603: The dexterity of their fingers. BigDog is a dynamically stable quadruped robot created in 2005 by Boston Dynamics with Foster-Miller , the NASA Jet Propulsion Laboratory , and the Harvard University Concord Field Station . Its successor was Spot. Also by NASA JPL, in collaboration with University of California, Santa Barbara Robotics Lab, is RoboSimian, with emphasis on stability and deliberation. It has been demonstrated at
450-531: 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 . Sauropodomorphs were adapted to browsing higher than any other contemporary herbivore, giving them access to high tree foliage. This feeding strategy is supported by many of their defining characteristics, such as:
475-534: The family Melanorosauridae. A more recent study by Yates (2007) indicates that the melanorosaurids were instead early sauropods . [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] This Sauropodomorph -related article is a stub . You can help Misplaced Pages by expanding it . Sauropodomorph Sauropodomorpha ( / ˌ s ɔːr ə ˌ p ɒ d ə ˈ m ɔːr f ə / SOR -ə- POD -ə- MOR -fə ; from Greek, meaning "lizard-footed forms")
500-522: 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 . Within Sauropodomorpha, there is a large clade named Plateosauria . The name Plateosauria
525-572: 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
SECTION 20
#1732868683518550-551: The same evolutionary pressure, instead of ( homologous ) traits derived from a shared ancestor. 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
575-745: The upper mouth bends down in what may be a beak. One of the earliest known sauropodomorphs, Saturnalia , was small and slender (1.5 metres, or 5 feet long); but, by the end of the Triassic, they were the largest dinosaurs of their time, and throughout the Jurassic and Cretaceous they kept on growing. Ultimately the largest sauropods, like Supersaurus , Diplodocus hallorum , Patagotitan , and Argentinosaurus , reached 30–40 metres (98–131 ft) in length, and 60,000–100,000 kilograms (65–110 US short tons ) or more in mass. Initially bipedal , as their size increased they evolved
600-515: 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. Peter Galton and Paul Upchurch in 2004 used a different definition: the last common ancestor of Plateosaurus engelhardti and Jingshanosaurus xinwaensis , and its descendants. In their cladistic analysis
625-468: Was popularized as a form of physical exercise by Georges Hebert . Kenichi Ito is a Japanese man famous for speed running on four limbs in competitions. In July 2005, in rural Turkey , scientists discovered five Turkish siblings who had learned to walk naturally on their hands and feet. Unlike chimpanzees , which ambulate on their knuckles , the Ulas family walked on their palms, allowing them to preserve
#517482