Dinosaur size
Size has been one of the most fascinating aspects of dinosaur paleontology, to both the general public and professional scientists. Dinosaurs show some of the most extreme variations in size of any land animal group, ranging from the tiny hummingbirds, which can weigh as little as three grams, to the extinct titanosaurs, which could weigh as much as.
Scientists will probably never be certain of the largest and smallest dinosaurs. This is because only a small fraction of animals ever fossilize, and most of these remain buried in the earth and will never be found. Few of the specimens that are recovered are complete skeletons, and impressions of skin and other soft tissues are rarely discovered. Rebuilding a complete skeleton by comparing the size and morphology of bones to those of similar, better-known species is an inexact art, and reconstructing the muscles and other organs of the living animal is, at best, a process of educated guesswork, and never perfect. Weight estimates for dinosaurs are much more variable than length estimates, because estimating length for extinct animals is much more easily done from a skeleton than estimating weight. Estimating weight is most easily done with the laser scan skeleton technique that puts a "virtual" skin over it, but even this is only an estimate.
The latest evidence suggests that dinosaur average size varied through the Triassic, early Jurassic, late Jurassic and Cretaceous periods, and dinosaurs probably only became widespread during the Jurassic. Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the 100- to 1,000-kilogram category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the 10- to 100-kilogram category. The mode of Mesozoic dinosaur body masses is between one and ten metric tonnes. This contrasts sharply with the size of Cenozoic mammals, estimated by the National Museum of Natural History as about.
Record sizes
The sauropods were the longest and heaviest dinosaurs. For much of the dinosaur era, the smallest sauropods were larger than anything else in their habitat, and the largest were an order of magnitude more massive than anything else that has walked the Earth since. Giant prehistoric mammals such as Paraceratherium and Palaeoloxodon were dwarfed by the giant sauropods, and only modern whales surpass them in weight, though they live in the oceans. There are several proposed advantages for the large size of sauropods, including protection from predation, reduction of energy use, and longevity, but it may be that the most important advantage was dietary. Large animals are more efficient at digestion than small animals, because food spends more time in their digestive systems. This also permits them to subsist on food with lower nutritive value than smaller animals. Sauropod remains are mostly found in rock formations interpreted as dry or seasonally dry, and the ability to eat large quantities of low-nutrient browse would have been advantageous in such environments.One of the tallest and heaviest dinosaurs known from good skeletons is Giraffatitan brancai. Its remains were discovered in Tanzania between 1907 and 1912. Bones from several similar-sized individuals were incorporated into the skeleton now mounted and on display at the Museum für Naturkunde Berlin; this mount is tall and long, and would have belonged to an animal that weighed between. One of the longest complete dinosaurs is the Diplodocus, which was discovered in Wyoming in the United States and displayed in Pittsburgh's Carnegie Natural History Museum in 1907.
There were larger dinosaurs, but knowledge of them is based entirely on a small number of fragmentary fossils. Most of the largest herbivorous specimens on record were discovered in the 1970s or later, and include the massive titanosaur Argentinosaurus huinculensis, which is the largest dinosaur known from uncontroversial evidence, estimated to have been and long. Some of the longest sauropods were those with exceptionally long, whip-like tails, such as the Diplodocus hallorum and the 33- to 35-metre-long Supersaurus.
In 2014, the fossilized remains of a previously unknown species of sauropod were discovered in Argentina. The titanosaur, named Patagotitan mayorum, would have been around 40m long and weighed around 77 tonnes, larger than any other previously found sauropod. The specimens found were remarkably complete, significantly more so than previous titanosaurs. Research as of 2017 estimated Patagotitan to have been long It has also been suggested that Patagotitan is not necessarily larger than Argentinosaurus and Puertasaurus.
Tyrannosaurus was for many decades the largest and best known theropod to the general public. Since its discovery, however, a number of other giant carnivorous dinosaurs have been described, including Spinosaurus, Carcharodontosaurus, and Giganotosaurus. These large theropod dinosaurs rivaled or even exceeded Tyrannosaurus in size, though more recent studies show some indication that Tyrannosaurus, although shorter, was the heavier predator. Specimens such as Sue and Scotty are both estimated to be the most massive theropods known to science. There is still no clear explanation for exactly why these animals grew so much larger than the land predators that came before and after them.
The largest extant theropod is the common ostrich, up to tall and weighs between.
The smallest non-avialan theropod known from adult specimens may be Anchiornis huxleyi, at in weight and in length. However, some studies suggest that Anchiornis was actually an avialan. The smallest dinosaur known from adult specimens which is definitely not an avialan is Parvicursor remotus, at and measuring long. When modern birds are included, the bee hummingbird Mellisuga helenae is smallest at and long.
Recent theories propose that theropod body size shrank continuously over the past 50 million years, from an average of down to, as they eventually evolved into modern birds. This is based on evidence that theropods were the only dinosaurs to get continuously smaller, and that their skeletons changed four times faster than those of other dinosaur species.
Sauropodomorphs
Sauropodomorph size is difficult to estimate given their usually fragmentary state of preservation. Sauropods are often preserved without their tails, so the margin of error in overall length estimates is high. Mass is calculated using the cube of the length, so for species in which the length is particularly uncertain, the weight is even more so. Estimates that are particularly uncertain are preceded by a question mark. Each number represents the highest estimate of a given research paper. One large sauropod, Maraapunisaurus fragillimus, was based on particularly scant remains that have been lost since their description by paleontologists in 1878. Analysis of the illustrations included in the original report suggested that M. fragillimus may have been the largest land animal of all time, weighing up to and measuring between long. One later analysis of the surviving evidence, and the biological plausibility of such a large land animal, suggested that the enormous size of this animal was an over-estimate due partly to typographical errors in the original report. This would later be challenged by a different study, which argued Cope's measurements were genuine and there's no basis for assuming typographical errors. The study, however, also reclassified the species and correspondingly gave a much lower length estimate of and a mass of.Generally, the giant sauropods can be divided into two categories: the shorter but stockier and more massive forms, and the longer but slenderer and more light-weight forms.
Because different methods of estimation sometimes give conflicting results, mass estimates for sauropods can vary widely causing disagreement among scientists over the accurate number. For example, the titanosaur Dreadnoughtus was originally estimated to weigh 59.3 tonnes by the allometric scaling of limb-bone proportions, whereas more recent estimates, based on three-dimensional reconstructions, yield a much smaller figure of 22.1–38.2 tonnes.
Heaviest sauropodomorphs
- Maraapunisaurus fragilimus :
- Argentinosaurus huinculensis:
- Puertasaurus reuili:
- Barosaurus lentus:
- Mamenchisaurus sinocanadorum:
- Patagotitan mayorum:
- Notocolossus gonzalezparejasi:
- Alamosaurus sanjuanensis:
- Apatosaurus ajax:
Longest sauropodomorphs
- Barosaurus lentus:
- Maraapunisaurus fragilimus :
- Puertasaurus reuili:
- Argentinosaurus huinculensis:
- Patagotitan mayorum:
- Supersaurus vivianae:
- Ruyangosaurus giganteus: 30 – 35 m
- Diplodocus hallorum:
- Alamosaurus sanjuanensis:
- Sauroposeidon proteles:
Shortest sauropods
- Ohmdenosaurus liasicus:
- Blikanasaurus cromptoni:
- Lirainosaurus astibiae:
- Magyarosaurus dacus:
- Europasaurus holgeri:
- Vulcanodon karibaensis:
- Isanosaurus attavipachi:
- Saltasaurus loricatus:
- Neuquensaurus australis:
- Antetonitrus ingenipes:
Lightest sauropods
- Blikanasaurus cromptoni:
- Astrodon johnstoni:
- Europasaurus holgeri:
- Magyarosaurus dacus:
- Bonatitan reigi:
- Lirainosaurus astibiae:
- Lapparentosaurus madagascariensis:
- Antetonitrus ingenipes:
- Lessemsaurus sauropoides:
- Neuquensaurus australis:
Lightest non-sauropod sauropodomorphs
- Eoraptor lunensis:
- Pampadromaeus barberenai:
- Saturnalia tupiniquim:
- Chromogisaurus novasi:
- Asylosaurus yalensis:
- Guaibasaurus candelariensis:
- Adeopapposaurus mognai:
- Coloradisaurus brevis:
- Anchisaurus polyzelus:
- Sarahsaurus aurifontanalis:
Shortest non-sauropod sauropodomorphs
- Agnosphitys cromhallensis:
- Eoraptor lunensis:
- Pampadromaeus barberenai:
- Saturnalia tupiniquim:
- Chromogisaurus novasi:
- Guaibasaurus candelariensis:
- Asylosaurus yalensis:
- Leyesaurus marayensis: ?
- Adeopapposaurus mognai:
- Unaysaurus tolentinoi:
Theropods
Heaviest theropods
- Spinosaurus aegyptiacus:
- Tyrannosaurus rex:
- Deinocheirus sp. :
- Carcharodontosaurus saharicus:
- Giganotosaurus carolinii:
- Acrocanthosaurus atokensis:
- Oxalaia quilombensis:
- Tyrannotitan chubutensis:
- Therizinosaurus cheloniformis:
- Deinocheirus mirificus:
- Chilantaisaurus tashuikouensis:
Longest theropods
- Spinosaurus aegyptiacus:
- Deinocheirus sp.:
- Epanterias amplexus:
- Sigilmassasaurus brevicollis:
- Giganotosaurus carolinii:
- Oxalaia quilombensis:
- Saurophaganax maximus:
- Mapusaurus roseae: ?
- Deltadromeus agilis:
- Carcharodontosaurus saharicus:
- Tyrannosaurus rex: 10-12.3m
Lightest theropods
- Mellisuga helenae:
- Mellisuga minima:
- Selasphorus rufus:
- Lophornis magnificus:
- Atthis heloisa:
- Lophornis brachylophus:
- Calypte costae:
- Calypte anna:
- Cratoavis cearensis:
- Gerygone albofrontata:
Shortest theropods
- Mellisuga helenae:
- Mellisuga minima:
- Lophornis magnificus:
- Cratoavis cearensis:
- Dicaeum ignipectus: -
- Chaetocercus heliodor:
- Myrmia micrura:
- Lophornis brachylophus:
- Atthis heloisa:
- Selasphorus rufus:
- Regulus regulus:
Shortest non-avialan theropods
- Unnamed :
- Epidexipteryx hui:
- "Ornithomimus" minutus:
- Palaeopteryx thompsoni: ?
- Parvicursor remotus:
- Nqwebasaurus thwazi:
- Mei long:
- Xixianykus zhangi:
- Jinfengopteryx elegans:
Lightest non-avialan theropods
- Parvicursor remotus:
- Epidexipteryx hui:
- Compsognathus longipes:
- Ceratonykus oculatus:
- Zhongjianosaurus yangi:
- Ligabueino andesi:
- Yi qi:
- Microraptor zhaoianus:
- Mahakala omnogovae:
- Mei long:
Ornithopods
Longest ornithopods
- Shantungosaurus giganteus:
- Edmontosaurus annectens:
- Hypsibema crassicauda: ?
- Hypsibema missouriensis : ?
- Iguanodon bernissartensis:
- Charonosaurus jiayinensis:
- Edmontosaurus regalis:
- Magnapaulia laticaudus:
- Saurolophus angustirostris:
- Ornithotarsus immanis: ?
Heaviest ornithopods
- Shantungosaurus giganteus:
- Iguanodon seeleyi:
- Edmontosaurus annectens:
- Saurolophus angustirostris:
- Iguanodon bernissartensis:
- Edmontosaurus regalis:
- Brachylophosaurus canadensis:
- Lanzhousaurus magnidens:
- Parasaurolophus walkeri:
- Charonosaurus jiayinensis:
Shortest ornithopods
- Gasparinisaura cincosaltensis:
- Leaellynasaura amicagraphica:
- Valdosaurus canaliculatus:
- Notohypsilophodon comodorensis:
- Fulgurotherium australe:
- Siluosaurus zhangqiani:
- Qantassaurus intrepidus:
- Changchunsaurus parvus:
- Thescelosaurus sp.:
- Yandusaurus hongheensis:
Lightest ornithopods
- Gasparinisaura cincosaltensis:
- Yueosaurus tiantaiensis:
- Fulgurotherium australe:
- Notohypsilophodon comodorensis:
- Yandusaurus hongheensis:
- Hypsilophodon foxii:
- Thescelosaurus sp.:
- Valdosaurus canaliculatus:
- Haya griva:
- Agilisaurus louderbacki:
Ceratopsians
Longest ceratopsians
- Eotriceratops xerinsularis:
- Triceratops horridus:
- Triceratops prorsus:
- Torosaurus latus:
- Ojoceratops fowleri:
- Titanoceratops ouranos:
- Pachyrhinosaurus canadensis:
- Achelousaurus horneri:
- Albertaceratops nesmoi:
- Pentaceratops sternbergii:
Heaviest ceratopsians
- Triceratops horridus:
- Triceratops prorsus:
- Ojoceratops fowleri:
- Bravoceratops polyphemus:
- Pachyrhinosaurus canadensis:
- Styracosaurus albertensis:
- Albertaceratops nesmoi:
- Chasmosaurus russelli:
- Chasmosaurus belli:
- Pentaceratops sternbergii:
Shortest ceratopsians
- Yamaceratops dorngobiensis:
- Liaoceratops yanzigouensis:
- Archaeoceratops yujingziensis:
- Microceratus gobiensis:
- Bagaceratops rozhdestvenskyi:
- Archaeoceratops oshimai:
- Psittacosaurus lujiatunensis:
- Micropachycephalosaurus hongtuyanensis:
- Chaoyangsaurus youngi:
- Xuanhuaceratops niei:
Lightest ceratopsians
- Liaoceratops yanzigouensis:
- Yamaceratops dorngobiensis:
- Psittacosaurus sinensis:
- Psittacosaurus lujiatunensis:
- Yinlong downsi:
- Micropachycephalosaurus hongtuyanensis:
- Chaoyangsaurus youngi:
- Xuanhuaceratops niei:
- Psittacosaurus gobiensis:
- Bagaceratops rozhdestvenskyi:
Pachycephalosaurs
Longest pachycephalosaurs
Size by overall length, including tail, of all pachycephalosaurs measuring or more in length.- Pachycephalosaurus wyomingensis:
- Stygimoloch spinifer:
- Gravitholus albertae: ?
Shortest pachycephalosaurs
- Wannanosaurus yansiensis:
- Colepiocephale lambei:
- Texacephale langstoni:
Thyreophorans
Longest thyreophorans
- Stegosaurus ungulatus:
- Stegosaurus stenops:
- Cedarpelta bilbeyhallorum:
- Dacentrurus armatus:
- Ankylosaurus magniventris:
- Tarchia gigantea:
- Sauropelta edwardsorum:
- Dyoplosaurus acutosquameus: ?
- Tuojiangosaurus multispinus:
- Wuerhosaurus homheni:
Heaviest thyreophorans
- Ankylosaurus magniventris:
- Dacentrurus armatus:
- Stegosaurus ungulatus:
- Stegosaurus stenops:
- Cedarpelta bilbeyhallorum:
- Hesperosaurus mjosi:
- Tuojiangosaurus multispinus:
- Wuerhosaurus homheni:
- Niobrarasaurus coleii:
- Gobisaurus domoculus:
Shortest thyreophorans
- Tatisaurus oehleri:
- Scutellosaurus lawleri:
- Dracopelta zbyszewskii:
- Minmi paravertebra:
Lightest thyreophorans
- Scutellosaurus lawleri:
- Emausaurus ernsti:
- Scelidosaurus harrisonii:
- Animantarx ramaljonesi:
- Struthiosaurus transylvanicus:
- Struthiosaurus austriacus:
- Gargoyleosaurus parkpinorum:
- Mymoorapelta maysi:
- Minmi paravertebra: