39-420: 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") 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
78-590: A monophyletic group or natural group , is a grouping of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree . In the taxonomical literature, sometimes the Latin form cladus (plural cladi ) is used rather than the English form. Clades are the fundamental unit of cladistics , a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual,
117-588: A population , or a species ( extinct or extant ). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic . Some of
156-479: A "ladder", with supposedly more "advanced" organisms at the top. Taxonomists have increasingly worked to make the taxonomic system reflect evolution. When it comes to naming , this principle is not always compatible with the traditional rank-based nomenclature (in which only taxa associated with a rank can be named) because not enough ranks exist to name a long series of nested clades. For these and other reasons, phylogenetic nomenclature has been developed; it
195-496: A 231.4 million year old ash layer, indicating it lived during the early Carnian of the Late Triassic . Panphagia is currently known from holotype PVSJ 874, the disarticulated remains of one partially grown individual of about 1.30 metres (4.3 ft) long. Portions of the skull, vertebrae , pectoral girdle , pelvic girdle , and hindlimb bones have been recovered. The russet-colored fossils were embedded in
234-446: A branch of mammals that split off after the end of the period when the clade Dinosauria stopped being the dominant terrestrial vertebrates 66 million years ago. The original population and all its descendants are a clade. The rodent clade corresponds to the order Rodentia, and insects to the class Insecta. These clades include smaller clades, such as chipmunk or ant , each of which consists of even smaller clades. The clade "rodent"
273-623: A clade can be described based on two different reference points, crown age and stem age. The crown age of a clade refers to the age of the most recent common ancestor of all of the species in the clade. The stem age of a clade refers to the time that the ancestral lineage of the clade diverged from its sister clade. A clade's stem age is either the same as or older than its crown age. Ages of clades cannot be directly observed. They are inferred, either from stratigraphy of fossils , or from molecular clock estimates. Viruses , and particularly RNA viruses form clades. These are useful in tracking
312-515: A greenish sandstone matrix and took several years to prepare and describe. Herrerasaurus Staurikosaurus Eoraptor Theropoda Panphagia Saturnalia Other sauropodomorphs Panphagia was described in 2009 by Ricardo N. Martínez and Oscar A. Alcober, both of the Museo de Ciencias Naturales, in San Juan, Argentina. They performed a phylogenetic analysis and found it to be
351-554: 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 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
390-422: A revised taxonomy based on a concept strongly resembling clades, although the term clade itself would not be coined until 1957 by his grandson, Julian Huxley . German biologist Emil Hans Willi Hennig (1913–1976) is considered to be the founder of cladistics . He proposed a classification system that represented repeated branchings of the family tree, as opposed to the previous systems, which put organisms on
429-429: A suffix added should be e.g. "dracohortian". A clade is by definition monophyletic , meaning that it contains one ancestor which can be an organism, a population, or a species and all its descendants. The ancestor can be known or unknown; any and all members of a clade can be extant or extinct. The science that tries to reconstruct phylogenetic trees and thus discover clades is called phylogenetics or cladistics ,
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#1732783618069468-469: 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 a number of characteristics with
507-519: 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
546-479: 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 Clade In biological phylogenetics , a clade (from Ancient Greek κλάδος (kládos) 'branch'), also known as
585-428: 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
624-476: Is in turn included in the mammal, vertebrate and animal clades. The idea of a clade did not exist in pre- Darwinian Linnaean taxonomy , which was based by necessity only on internal or external morphological similarities between organisms. Many of the better known animal groups in Linnaeus's original Systema Naturae (mostly vertebrate groups) do represent clades. The phenomenon of convergent evolution
663-515: Is responsible for many cases of misleading similarities in the morphology of groups that evolved from different lineages. With the increasing realization in the first half of the 19th century that species had changed and split through the ages, classification increasingly came to be seen as branches on the evolutionary tree of life . The publication of Darwin's theory of evolution in 1859 gave this view increasing weight. In 1876 Thomas Henry Huxley , an early advocate of evolutionary theory, proposed
702-489: Is still controversial. As an example, see the full current classification of Anas platyrhynchos (the mallard duck) with 40 clades from Eukaryota down by following this Wikispecies link and clicking on "Expand". The name of a clade is conventionally a plural, where the singular refers to each member individually. A unique exception is the reptile clade Dracohors , which was made by haplology from Latin "draco" and "cohors", i.e. "the dragon cohort "; its form with
741-401: Is supported by many of their defining characteristics, such as: 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
780-733: The Carnian age of the Late Triassic period in what is now northwestern Argentina . Fossils of the genus were found in the La Peña Member of the Ischigualasto Formation in the Ischigualasto-Villa Unión Basin . The name Panphagia comes from the Greek words pan , meaning "all", and phagein , meaning "to eat", in reference to its inferred omnivorous diet. Panphagia is one of
819-592: 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
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#1732783618069858-464: 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:
897-499: The Panphagia fossils and those of its closest kin, Martínez and Alcober concluded that the evolution of saurischian dinosaurs likely began with small, cursorial animals similar to Panphagia , and that there is a "general similarity among all of these basal dinosaurs [suggesting] that few structural changes stand" between Panphagia , Eoraptor , and two basal theropods which have yet to be described. The type species of Panphagia
936-537: The gizzard stones of birds and crocodiles, to help digest tough plant fibers. The front of 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
975-672: The Earth. The prosauropods , which preceded the sauropods, were smaller and were often able to walk on two legs. The sauropodomorphs 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 . Sauropodomorphs were adapted to browsing higher than any other contemporary herbivore, giving them access to high tree foliage. This feeding strategy
1014-640: 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,
1053-509: 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 ,
1092-461: 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
1131-475: The earliest known dinosaurs, and is an important find which may mark the transition of diet in early sauropodomorph dinosaurs. Fossils of Panphagia were found in late 2006 by the Argentinean paleontologist Ricardo N. Martínez in rocks of the Ischigualasto Formation of Valle Pintado, Ischigualasto Provincial Park , San Juan Province , Argentina . The bones were found at approximately the same level as
1170-534: 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
1209-492: 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 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
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1248-518: The latter term coined by Ernst Mayr (1965), derived from "clade". The results of phylogenetic/cladistic analyses are tree-shaped diagrams called cladograms ; they, and all their branches, are phylogenetic hypotheses. Three methods of defining clades are featured in phylogenetic nomenclature : node-, stem-, and apomorphy-based (see Phylogenetic nomenclature§Phylogenetic definitions of clade names for detailed definitions). The relationship between clades can be described in several ways: The age of
1287-433: The most basal known sauropodomorph dinosaur: the fossils shared similar features to those of Saturnalia , an early sauropodomorph, including similarities in the ischium , astragalus , and the scapular blade. Yet the fossils also exhibited similar features to those of Eoraptor , an early omnivorous sauropodomorph, including hollow bones, sublanceolate teeth, and overall proportions. Based on analysis and comparison of
1326-410: 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 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
1365-482: The relationships between organisms that the molecular biology arm of cladistics has revealed include that fungi are closer relatives to animals than they are to plants, archaea are now considered different from bacteria , and multicellular organisms may have evolved from archaea. The term "clade" is also used with a similar meaning in other fields besides biology, such as historical linguistics ; see Cladistics § In disciplines other than biology . The term "clade"
1404-561: 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
1443-520: The spread of viral infections . HIV , for example, has clades called subtypes, which vary in geographical prevalence. HIV subtype (clade) B, for example is predominant in Europe, the Americas and Japan, whereas subtype A is more common in east Africa. Panphagia protos Panphagia is a genus of sauropodomorph dinosaur described in 2009. It lived around 231 million years ago, during
1482-423: Was coined in 1957 by the biologist Julian Huxley to refer to the result of cladogenesis , the evolutionary splitting of a parent species into two distinct species, a concept Huxley borrowed from Bernhard Rensch . Many commonly named groups – rodents and insects , for example – are clades because, in each case, the group consists of a common ancestor with all its descendant branches. Rodents, for example, are
1521-513: 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
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