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Some Awesome Pterosaurs

Friday, December 2, 2016

Pterosaurs (meaning “winged lizard”) were flying reptiles of the extinct clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous (228 to 66 million years ago). Pterosaurs are the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger. Early species had long, fully toothed jaws and long tails, while later forms had a highly reduced tail, and some lacked teeth. Many sported furry coats made up of hair-like filaments known as pycnofibers, which covered their bodies and parts of their wings. Pterosaurs spanned a wide range of adult sizes, from the very small anurognathids to the largest known flying creatures of all time, including Quetzalcoatlus and Hatzegopteryx.

Distribution of pterosaur fossil locations. Colored species or genera names correspond to their taxonomic group. Adapted from Witton (2013). Taxonomic groups based on Unwin et al. (2010). Author: Andrew Z. Colvin

Tapejara

Tapejara is but one of a larger group of distinctive pterosaurs that have large laterally compressed‭ (‬large when viewed from the side but thin from the front‭) ‬crests combined with a‭ ‬relatively short and deep set of jaws.‭ ‬The diet of Tapejara has since been the subject of a lot of debate as while most consider it to be a piscivorous fish-eater‭; ‬some consider the possibility of it and possibly other similar pterosaurs being fruit eating frugivores.

Ornithocheirus

Ornithocheirus has enjoyed a surge in popularity since the end of the twentieth century mainly in part due to possible specimens of very similar pterosaurs discovered in Brazil,‭ ‬as well as a centre stage appearance in the popular BBC series‭ ‘‬Walking with Dinosaurs‭’‬.‭ ‬However while the latter depiction was as accurate portrayal of its possible lifestyle,‭ ‬the twelve meter wingspan quoted in the show is beyond the scope of any fossil material that has been attributed to this genus.‭ ‬Instead Ornithocheirus had an upper wingspan of five meters,‭ ‬although the addition of new material may see this size increase to six meters.

No top ten pterosaur list would be complete without the member that is considered the largest of the group.‭ ‬However while Quetzalcoatlus is considered the largest,‭ ‬the exact size is a matter of scaling up missing bones by comparison to other pterosaurs,‭ ‬something that has created a‭ ‬degree of variability in size quotations.‭ ‬Also while Quetzalcoatlus is generally regarded as the largest,‭ ‬others such‭ ‬as Hatzegopteryx are in a position to take this title away from Quetzalcoatlus.‭ ‬Only a general lack of fossils results makes it hard to ascertain one or the other as an absolute.‭ ‬The large size of Quetzalcoatlus has made it hard for many to imagine such a large creature as being capable of flight as no living animal is capable of matching Quetzalcoatlus’s size with the ability to fly.‭ ‬However just because there is no living precedent to prove this,‭ ‬it does not mean that flight for‭ ‬Quetzalcoatlus was impossible.

‬Pteranodon

Probably the most instantly recognisable pterosaur due to its inclusion in so many dinosaur books and films,‭ ‬Pteranodon has not been without its share of controversy.‭ ‬This is mainly centred around the shape and function of the back crest.‭ ‬Differences between male and females individuals were for a time taken to indicate different species,‭ ‬something that was not helped by‭ ‬the fact that males had crests similar to the females until they reached maturity.‭ ‬The crest has also occasionally been depicted as supporting a skin sail,‭ ‬although most reconstructions just keep it as a bony projection from the back of the cranium.‭ ‬The name Pteranodon actually translates to English‭ ‬as‭ ‘‬toothless beak‭’‬,‭ ‬and this makes it very easy to spot inaccurate depictions as Pteranodon is often given teeth to make it look more fearsome.‭

Dsungaripterus

Another specialist feeder was Dsungaripterus which had a highly adapted beak.‭ ‬The front portion of this beak was toothless and curved upwards,‭ ‬something that is thought to have been an adaptation for digging out shellfish from soft ground.‭ ‬Like a crowbar Dsungaripterus could drive this beak into the mud and lever out shellfish that would have buried themselves‭ ‬to survive‭ ‬during‭ ‬the‭ ‬low tide.‭ ‬The teeth at the back of the mouth were also quite small and not especially sharp.‭ ‬This made them more robust and effective for crushing thin shells that would have protected shellfish from other predators.‭ ‬Further evidence for this feeding behaviour also comes from the fact that dsungaripterid pterosaurs are usually found in marine environments.

Pterodaustro

There have been many filter feeding pterosaurs discovered but Pterodaustro is easily one of the most specialised of these.‭ ‬Instead of just a few teeth arranged in a spoon shape at the end of the jaws‭ ‬ like some of the members,‭ ‬Pterodaustro had several hundred teeth that pointed up from the lower jaw that created a fine comb which allowed mouthfuls of water to flow out while small invertebrates were trapped within.‭ ‬Also many aquatic invertebrates are known to have carotenid pigment that when broken down by the liver turns to a pink/orange,‭ ‬which has led to many palaeontologists recognising the possibility that Pterodaustro may have been a bright pink to deep red in body colour.‭ ‬This may in part explain why Pterodaustro was nocturnally active as indicated by study of Pterodaustro’s scleral rings,‭ ‬something that would have made it less obvious to potential predators.

Eudimorphodon

With fossils dating back to the Norian stage of the Triassic,‭ ‬Eudimorphodon is one of the earliest pterosaurs to appear in the fossil record.‭ ‬This tells palaeontologists that while the exact common ancestor to all pterosaurs remains unknown,‭ ‬it must appear in the fossil record before the Norian stage.‭ ‬This will allow palaeontologists who are searching for this ancestor to focus their search upon deposits that date back to before this age.

Darwinopterus

Darwinopterus was a major discovery because it has features that are seen in both basal and advanced pterosaurs.‭ ‬This makes Darwinopterus what is called a transitory form‭ (‬palaeontologists generally don’t like the term‭ ‘‬missing link‭’) ‬that shows the evolution of primitive pterosaurs into their more advanced forms.‭ ‬Not only is this interesting in itself but the really exciting discovery associated with this is that the pterosaurs do not seem to have evolved their whole bodies at once but instead just evolved certain areas.‭ ‬This is termed modular evolution and is used to refer to just certain body areas such as the skull,‭ ‬hands,‭ ‬legs,‭ ‬tail,‭ ‬etc.‭ ‬changing while the rest of the body remains the same.‭

Rhamphorhynchus

Another famous pterosaur,‭ ‬Rhamphorhynchus has been used to name the Rhamphorhynchidae,‭ ‬the group of basal‭ (‬sometimes called‭ ‘‬primitive‭’) ‬pterosaurs.‭ ‬This means that Rhamphorhynchus had primitive features such as a long tail‭ (‬that in Rhamphorhynchus was straight with a vane on the end that may‭ ‬have‭ ‬been an inflight steering aid‭) ‬and short neck vertebrae that connected more to the posterior‭ (‬back‭) ‬of the skull like in lizards.‭ ‬The hands of Rhamphorhynchus are also better suited for holding onto vertical surfaces,‭ ‬an ability that would be reduced in later pterosaurs.‭ ‬The proportionately long and sharp teeth are thought to have been used to‭ ‬capture small vertebrates such as fish from near the surface of the water.

Pterodactylus

This is the pterosaur that started the science of pterosaur palaeontology as it was the first to be described as one.‭ ‬However the correct identification‭ ‬was a considerable time coming with some researchers describing it as a bat like creature,‭ ‬and some even thinking that it was an aquatic animal with the wings being used for swimming.‭ ‬In fact even after the correct identification by Georges Cuvier in‭ ‬1809‭ ‬many naturalists still held firm to the earlier ideas.‭ ‬Pterodactylus has been used to name the group of‭ ‘‬advanced‭’ ‬Pterosaurs the Pterodactyloidea.‭ ‬Although there are many key differences between genera that belong to this group they all share some common features such as short tails,‭ ‬longer neck vertebrae that attach to more underneath the base of the skull rather than the rear,‭ ‬and wings better adapted to flying.

Pterodactylus is also this pterosaur that the more common public name‭ ‘‬Pterodactyl‭’ ‬is derived from,‭ ‬a name that has resulted in the general public referring to pterosaurs as‭ ‘‬pterodactyls‭’‬.‭ ‬The problem with this is that pterodactyl is not recognised by any scientific body as being a valid description of the pterosaurs,‭ ‬or any specific genera.

Sordes

Fossils of this pterosaur have been found with the impression of an extensive covering of pycnofibres,‭ ‬loosely referred to as hairs.‭ ‬These pycnofibres are not like mammalian hair however and instead are hollow filaments,‭ ‬although they would have served an insulatory purpose like mammalian hair.‭ ‬Further discoveries such as Jeholopterus also have impressions of pycnofibres,‭ ‬and many pterosaurs are now thought to have had a covering of them,‭ ‬but due to their fragile nature impressions of pycnofibres only preserve when conditions are exactly right.

Anurognathus

‬This is a good representative of the group of basal pterosaurs that had short but wide mouths.‭ ‬These mouths had long thin teeth that show them to be specialised insectivores,‭ ‬probably taking large flying insects‭ ‬while‭ ‬on the wing.

Nyctosaurus

Very similar to Pteranodon,‭ ‬Nyctosaurus had a greatly enlarged‭ ‘‬L-shaped‭’ ‬crest that rose up from the top of its skull.‭ ‬Like with Pteranodon this has been speculated as being the support for a huge skin sail,‭ ‬but modern analysis keeps pointing to the crest just being a bony L structure.

Mounted female and male G. sternbergi skeletons at the Royal Ontario Museum

Source: www.natgeo.com

Ornitholestes

Friday, December 2, 2016

Ornitholestes (meaning “bird robber”) is a small theropod dinosaur of the late Jurassic (Brushy Basin Member of the Morrison Formation, middle Kimmeridgian age, about 154 million years ago) of Western Laurasia (the area that was to become North America).

To date, Ornitholestes is known only from a single partial skeleton with a badly crushed skull found at the Bone Cabin Quarry near Medicine Bow, Wyoming, in 1900. It was described by Henry Fairfield Osborn in 1903. An incomplete hand was later attributed to Ornitholestes, although it now appears to belong to Tanycolagreus. The type (and only known) species is O. hermanni. The specific name honors the American Museum of Natural History preparator Adam Hermann.

Ornitholestes’ reputation as a bird-eater has much in common with Oviraptor‘s reputation as an egg-stealer: these were inferences drawn on the basis of insufficient knowledge (and in the case of Ornitholestes, the myth was perpetuated by a famous painting by Charles R. Knight depicting this dinosaur preparing to eat a captured Archaeopteryx).
 
Casts of Ornitholestes hermanni. On display at the Royal Tyrrell Museum, Alberta, Canada.
The infraorder Coelurosauria, coined in 1914 by Friedrich von Huene, was traditionally a taxonomic wastebasket into which all small theropods were placed. Ornitholestes, due to its small size, was therefore generally classified as a coelurosaur. In 1986, Jacques Gauthier redefined this and several other paleontological terms in a more rigorous fashion, based on cladistic methods. Tetanurae was defined as modern birds and all theropods more closely related to modern birds than to ceratosaurs, while Coelurosauria now comprised all members of Tetanurae more closely related to modern birds than to carnosaurs. In 1988, Gregory S. Paul suggested that Ornitholestes was very similar in skull structure to Proceratosaurus, a Middle Jurassic theropod from England.

Mononykus

Friday, December 2, 2016

Mononykus

Mononykus (meaning “one claw”) was a theropod dinosaur from late Cretaceous Mongolia (Nemegt Formation, about 70 million years ago) with long, skinny legs. It moved about on two legs, was likely very nimble and could run at high speeds, something that would have been useful in the open flood plains where it lived. It had a small skull, and its teeth were small and pointed, suggesting that it ate insects and small animals, such as lizards and mammals. Its large eyes might have allowed Mononykus to hunt by night, when it was cooler and there would have been fewer predators about. Mononykus was originally named Mononychus in 1993, but later that year, it was renamed because the original name had already been used for a beetle named by Johann Schueppel, a German entomologist.
 
Size comparison of several parvicursorine dinosaurs. From left to right: Parvicursor remotus (green), Ceratonykus oculatus (red), Shuvuuia deserti (blue), and Mononykus olecranus (violet). Scaled to tibia length in their respective descriptions. Author: Matthew Martyniuk
Mononykus was a small dinosaur, only 1 metre (3.3 ft) long. Other characteristics include fused wrist bones similar to those of birds, and a keeled breastbone. It differed from close relatives Shuvuuia and Parvicursor in several details of its skeleton, including a pubic bone that is triangular in cross section, and different proportions in the toe bones.
 
Mononykus was a member of the family Alvarezsauridae and, like its relatives, had very strange, stubby forearms with one large, approximately 7.5-centimetre (3.0 in) long claw (hence its name). The other two claws had disappeared (however, a close relative of MononykusShuvuuia, had two vestigial claws, alongside one large claw). The purpose of these highly specialized arms is still a mystery, but some scientists have suggested they were used to break open termite mounds (like modern anteaters), and therefore it is possible that they fed primarily on insects.

In a 2001 study conducted by Bruce Rothschild and other paleontologists, 15 foot bones referred to Mononykus were examined for signs of stress fracture, but none were found.

Muttaburrasaurus

Friday, December 2, 2016

Muttaburrasaurus by PaleoGuy on DeviantArt

Muttaburrasaurus was a genus of herbivorous ornithopod dinosaur, which lived in what is now northeastern Australia sometime between 112 and 99.6 million years ago during the early Cretaceous Period. It has been recovered in some analyses as a member of the iguanodontian family Rhabdodontidae. After Kunbarrasaurus, it is Australia’s most completely known dinosaur from skeletal remains. It was named after Muttaburra, the site in Queensland, Australia, where it was found.

Muttaburrasaurus was about 8 metres (26 ft) and weighed around 2.8 metric tons (3.1 short tons). The femur of the holotype has a length of 1015 millimetres.

Whether Muttaburrasaurus is capable of quadrupedal movement has been debated; it was originally thought to be an “Iguanodontid”; thought recent studies indicate a rhabdodont position. Ornithopods this basal were incapable of quadrupedal movement. Originally reconstructing Muttaburrasaurus with a thumb spike, Molnar later doubted such a structure was present. The foot was long and broad, with four toes.

Reconstructed skeleton at the Queensland Museum

The species was initially described from a partial skeleton found by grazier Doug Langdon in 1963 at Rosebery Downs Station beside Thomson River near Muttaburra, in the Australian state of Queensland, which also provides the creature's generic name. The remains were collected by paleontologist Dr Alan Bartholomai and entomologist Edward Dahms. After a lengthy preparation of the fossils, it was named in 1981 by Bartholomai and Ralph Molnar, who honoured its discoverer with its specific name langdoni.

The holotype, specimen QM F6140, was found in the Mackunda Formation dating to the Albian-Cenomanian. It consists of a partial skeleton with skull and lower jaws. The underside of the skull and the back of the mandibula, numerous vertebrae, parts of the pelvis, and parts of the front and hind limbs have been preserved.

Molnar originally assigned Muttaburrasaurus to the Iguanodontidae. Later authors suggested more basal euornithopod groups such as the Camptosauridae, Dryosauridae or Hypsilophodontidae. Studies by Andrew McDonald indicate a position in the Rhabdodontidae.

Reconstructed skeleton casts of Muttaburrasaurus, sponsored by Kellogg Company, have been put on display at a number of museums, including the Queensland Museum, Flinders Discovery Centre, and National Dinosaur Museum in Australia.

Mounted skull of a Muttaburrasaurus langdoni at the Australian Museum, Sydney. Photo by Matt Martyniuk (Dinoguy2)

Muttaburrasaurus had very powerful jaws equipped with shearing teeth. Whereas in more derived euornithopod species the replacement teeth alternated with the previous tooth generation to form a tooth battery, in Muttaburrasaurus they grew directly under them and only a single erupted generation was present, thus precluding a chewing motion. An additional basal trait was the lack of a primary ridge on the teeth sides, which show eleven lower ridges. In 1981 Molnar speculated that these qualities indicated an omnivorous diet, implying that Muttaburrasaurus occasionally ate carrion. In 1995 he changed his opinion, suspecting that Muttaburrasaurus's dental system is evolutionarily convergent with the ceratopsian system of shearing teeth. They would have been an adaptation for eating tough vegetation such as cycads.

Source: www.ifls.com / www.nageo.com

Kunbarrasaurus

Wednesday, November 30, 2016

An artist impression of Kunbarrasaurus ieversi. Image credit: © Australian Geographic.

Kunbarrasaurus is a genus of small herbivorous ankylosaurian dinosaur from the Cretaceous of Australia.

In November 1989, at Marathon Station near Richmond, Queensland, the skeleton was discovered of an ankylosaurian. In January 1990 it was secured by a team led by Ralph Molnar. In 1996, in a provisional description, Molnar concluded that it could be referred to the genus Minmi as a Minmi sp. Subsequently, the specimen was further prepared by an acid bath and investigated by a CAT scan. The new information led to the conclusion that the species could be named in a separate genus of ankylosaur.

In 2015, Lucy G. Leahey, Ralph E. Molnar, Kenneth Carpenter, Lawrence M. Witmer en Steven W. Salisbury named and described the type species Kunbarrasaurus ieversi. The genus name is derived from Kunbarra - the word for 'shield' in the Mayi language of the local Wunumara people. The specific name ieversi honours Mr Ian Ivers, the property manager who originally found the fossil. The description was limited to the skull. Kunbarrasaurus was one of eighteen dinosaur taxa from 2015 to be described in open access or free-to-read journals.

Kunbarrasaurus By cisiopurple

The holotype, QM F1801, was found in a layer of the Allaru Formation, marine sediments dating from the late Albian, or possibly the early Cenomanian. It consists of an almost complete skeleton with skull, containing the vertebral column up to the middle tail, the left shoulder girdle, the left arm minus the hand, the pelvis, both thighbones and most of the body armour. Both the bones and the armour are largely articulated. In the belly region remains have been found of the animal's last meal. The specimen represents the most complete dinosaur skeleton ever found in Eastern Gondwana (Australia, Antarctica, Madagascar and India) and the most complete ankylosaurian skeleton from the entirety of the Gondwanan continents

Kunbarrasaurus was a small armoured dinosaur, that was quadrupedal and had a long tail.

CT scan of the skull, showing internal components

In 2015, some distinguishing traits of the skull of Kunbarrasaurus were established. The roof of the skull is almost perfectly flat, apart from a limited convex profile of the postorbital bone and the nasal bone. The edges of the skull top, formed by the prefrontal, supraorbital and postorbital bones, make a right angle with the skull sides. The supraorbital is made up of one bone instead of two or three.

Kunbarrasaurus was in 2015 placed in the Ankylosauria. The same year Victoria Arbour e.a. had entered QM F1801 and the Minmi holotype as separate operational taxonomic units in their analysis. Whereas Minmi was recovered as a basal member of the Ankylosauridae, QM F1801 had a basal position in Ankylosauria, i.e. was too "primitive" to be included in either the Ankylosauridae or Nodosauridae. In the 2015 description of Kubarrasaurus on qualitative considerations such a position was indeed deemed likely.

Minmi

Wednesday, November 30, 2016

Minmi by atrox1

Minmi is a genus of small herbivorous ankylosaurian dinosaur that lived during the early Cretaceous Period of Australia, about 119 to 113 million years ago.

Minmi was a small herbivorous quadrupedal armoured ankylosaurian. In 2010, Gregory S. Paul estimated its length at three metres, its weight at three hundred kilogrammes. For an ankylosaurian, Minmi had long limbs, perhaps used to quickly search cover under brushes when threatened by large predators which might have been able to flip the small animal on its back.

Unlike other ankylosaurians, Minmi had horizontally oriented plates of bones that ran along the sides of its vertebrae, hence its specific name, paravertebra. Molnar in 1980 acknowledged that these were ossified tendons, but denied that they were homologous to the ossified tendons of other Ornithischia and claimed that they resembled the pathological tendon aponeurosis of modern crocodiles. Victoria Megan Arbour in 2014 deemed this unlikely and could find only one autapomorphy in the holotype: the high vertical extent of the musculus articulospinalis tendon ossification at its outer front end, wrapping itself around the side process of the vertebra. In 2015, Arbour and Philip Currie concluded that even this was not unique, which would mean the holotype had no diagnostic features and Minmi would be a nomen dubium. However, the 2015 description of Kunbarrasaurus announced that new distinguishing traits of Minmi had been discovered and that it should be considered a valid taxon.

Image of Minmi skeleton by Gary Cranitch, © Queensland Museum.

In 1980, Molnar placed Minmi in the Ankylosauria. In 1987, he thought it was a member of the Nodosauridae. In 2011, a new cladistic analysis performed by Thompson et al. recovered Minmi as the basalmost known ankylosaurid. Arbour & Currie entered Minmi and Minmi sp. as separate operational taxonomic units in their analysis and recovered Minmi as the basalmost ankylosaurid but Minmi sp. (= Kunbarrasaurus) as a more basal ankylosaurian, too "primitive" to be included in either the Ankylosauridae or Nodosauridae. Paul in 2010 suggested that both taxa were part of a Minmidae, an ancient and very basal ankylosaurian lineage, also including Antarctopelta, that had become isolated on Gondwana.

Megalosaurus

Wednesday, November 30, 2016

Artist’s impression of how Victorian paleontologists thought Megalosaurus bucklandii looked (right), compared with how we now understand it to have looked (left). Image credit: Mark Garlick / University of Warwick.

Megalosaurus (meaning "Great Lizard") is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period (Bathonian stage, 166 million years ago) of Southern England. Although fossils from other areas have been assigned to the genus, the only certain remains of Megalosaurus come from Oxfordshire and date to the late Middle Jurassic.

Megalosaurus was, in 1824, the first genus of non-avian dinosaur to be validly named. The type species is Megalosaurus bucklandii, named in 1827. In 1842, Megalosaurus was one of three genera on which Richard Owen based his Dinosauria. On Owen's directions a model was made as one of the Crystal Palace Dinosaurs, which greatly increased the public interest for prehistoric reptiles. Subsequently, over fifty other species would be classified under the genus, originally because dinosaurs were not well known, but even during the 20th century after many dinosaurs had been discovered. Today it is understood these additional species were not directly related to M. bucklandii, which is the only true Megalosaurus species. Because a complete skeleton of it has never been found, much is still unclear about its build.

Size comparison (human in blue, lectotype in pink, largest specimen in red)

Buckland had not provided a specific name, as was not uncommon in the early nineteenth century, when the genus was still seen as the more essential concept. In 1826, Ferdinand von Ritgen gave this dinosaur a complete binomial, Megalosaurus conybeari, which however was not much used by later authors and is now considered a nomen oblitum. A year later, in 1827, Gideon Mantell included Megalosaurus in his geological survey of southeastern England, and assigned the species its current valid binomial name, Megalosaurus bucklandii. Until recently, the form Megalosaurus bucklandi was often used, a variant first published in 1832 by Christian Erich Hermann von Meyer – and sometimes erroneously ascribed to von Ritgen – but the more original M. bucklandii has priority.

During the last part of the eighteenth century, the number of fossils in British collections quickly increased. According to an hypothesis published by science historian Robert William Theodor Gunther in 1925, among them was a partial lower jaw of Megalosaurus, acquired in October 1797 by Christopher Pegge for 10s.6d. and added to the collection of the Anatomy School of Christ Church college.

Lithography from William Buckland's "Notice on the Megalosaurus or great Fossil Lizard of Stonesfield", 1824. Caption reads "anterior extremity of the right lower jaw of the Megalosaurus from Stonesfield near Oxford".

In the early nineteenth century, more discoveries were made. In 1815, John Kidd reported the find of bones of giant tetrapods, again at the Stonesfield quarry. The layers there are currently considered part of the Taynton Limestone Formation, dating to the mid-Bathonian stage of the Jurassic Period. The bones were apparently acquired by William Buckland, Professor of Geology at the University of Oxford and dean of Christ Church. Buckland also studied a lower jaw, according to Gunther the one bought by Pegge. Buckland did not know to what animal the bones belonged but, in 1818, after the Napoleonic Wars, the French comparative anatomist Georges Cuvier visited Buckland in Oxford and realised that they were those of a giant lizard-like creature. Buckland further studied the remains with his friend William Conybeare who in 1821 referred to them as the "Huge Lizard". In 1822 Buckland and Conybeare, in a joint article to be included in Cuvier's Ossemens, intended to provide scientific names for both gigantic lizard-like creatures known at the time: the remains found near Maastricht would be named Mosasaurus – then seen as a land-dwelling animal – while for the British lizard Conybeare had devised the name Megalosaurus, from the Greek μέγας, megas, "large". That year a publication failed to occur, but the physician James Parkinson already in 1822 announced the name Megalosaurus, illustrating one of the teeth and revealing the creature was forty feet long and eight feet high. It is generally considered the name in 1822 was still a nomen nudum ("naked name"). Buckland, urged on by an impatient Cuvier, continued to work on the subject during 1823, letting his later wife Mary Morland provide drawings of the bones, that were to be the basis of illustrating lithographies. Finally, on 20 February 1824, during the same meeting of the Geological Society of London in which Conybeare described a very complete specimen of Plesiosaurus, Buckland formally announced Megalosaurus. The descriptions of the bones in the Transactions of the Geological Society, in 1824, constitute a valid publication of the name. Megalosaurus was the first non-avian dinosaur genus named; the first of which the remains had with certainty been scientifically described was Streptospondylus, in 1808 by Cuvier.

Fossil specimens referred to M. bucklandii, Oxford University Museum of Natural History. The display shows most of the original syntype series, including the lectotype dentary, identified by Buckland in 1824

Early reconstructions

The first reconstruction was given by Buckland himself. He considered Megalosaurus to be a quadruped. He thought it was an "amphibian", i.e. an animal capable of both swimming in the sea and walking on land. Generally, in his mind Megalosaurus resembled a gigantic lizard, but Buckland already understood from the form of the thighbone head that the legs were not so much sprawling as held rather upright. In the original description of 1824, Buckland repeated Cuvier's size estimate that Megalosaurus would have been forty feet long with the weight of a seven foot tall elephant. However, this had been based on the remains present at Oxford. Buckland had also been hurried into naming his new reptile by a visit he had made to the fossil collection of Mantell, who during the lecture announced to have acquired a fossil thighbone of enormous magnitude, twice as long as that just described. Today, this is known to have belonged to Iguanodon, or at least some iguanodontid, but at the time both men assumed this bone belonged to Megalosaurus also. Even taking into account the effects of allometry, heavier animals having relatively stouter bones, Buckland was forced in the printed version of his lecture to estimate the maximum length of Megalosaurus at sixty to seventy feet. The existence of Megalosaurus posed some problems for Christian orthodoxy, which typically held that suffering and death had only come into the world through Original Sin, which seemed irreconcilable with the presence of a gigantic devouring reptile during a pre-Adamitic phase of history. Buckland rejected the usual solution, that such carnivores would originally have been peaceful vegetarians, as infantile and claimed in one of the Bridgewater Treatises that Megalosaurus had played a beneficial rôle in creation by ending the lives of old and ill animals, "to diminish the aggregate amount of animal suffering".

1854 reconstruction in Crystal Palace Park guided by Richard Owen presents Megalosaurus as a quadruped; modern reconstructions make it bipedal, like most theropods

In 1824, Buckland assigned Megalosaurus to the Sauria, assuming within the Sauria a close affinity with modern lizards, more than with crocodiles. In 1842, Owen made Megalosaurus one of the first three genera placed in the Dinosauria. In 1850, Prince Charles Lucien Bonaparte coined a separate family Megalosauridae with Megalosaurus as the type genus. For a long time, the precise relationships of Megalosaurus remained vague. It was seen as a "primitive" member of the Carnosauria, the group in which most large theropods were united.

In the late 20th century the new method of cladistics allowed for the first time to exactly calculate how closely various taxa were related to each other. In 2012, Matthew Carrano et al. showed that Megalosaurus was the sister species of Torvosaurus within the Megalosaurinae

Megalosaurus By Manuelsaurus

Living in what is now Europe, during the Jurassic Period (~201 to ~145 million years ago), Megalosaurus may have hunted stegosaurs and sauropods. Repeated descriptions during the nineteenth and early twentieth century of Megalosaurus hunting Iguanodon (another of the earliest dinosaurs named) through the forests that then covered the continent are now known to be inaccurate, because Iguanodon skeletons are found in much younger Early Cretaceous formations. The only specimens belonging to Megalosaurus bucklandii are from the Lower/Middle Bathonian of Oxfordshire and Gloucestershire. No material from outside of the Bathonian formations of England can be referred to Megalosaurus. It lived alongside the theropods Cruxicheiros, Iliosuchus and Streptospondylus, and the sauropods Cardiodon, Cetiosaurus, and possibly Cetiosauriscus. The pterosaur Rhamphocephalus, and indeterminate sauropod and ornithopod remains have also been found alongside fossils of Megalosaurus.

Massospondylus

Wednesday, November 30, 2016

Massospondylus

Massospondylus is a genus of sauropodomorph dinosaur from the Early Jurassic Period (Hettangian to Pliensbachian ages, ca. 200–183 million years ago). It was described by Sir Richard Owen in 1854 from remains discovered in South Africa, and is thus one of the first dinosaurs to have been named. Fossils have since been found at other locations in South Africa, Lesotho, and Zimbabwe.
 
Massospondylus was lightly built for a prosauropod, and much of its length was accounted for by its long neck and tail. Its body was similar in size to that of a large dog. The enlarged sickle-like thumb claws seen in other prosauropods were particularly well developed. We do not know exactly how Massospondylus used these huge claws. They would no doubt have made formidable weapons when the animal reared up on its hind legs to ward off predators-or perhaps to fight rival member of the species for mates. They may also have been useful in gathering food.

Mounted Massospondylus skeleton cast at the Natural History Museum, London, showing an outdated quadrupedal pose. Author: Ballista

Although Massospondylus was long depicted as quadrupedal, a 2007 study found it to be bipedal. It was probably a plant eater (herbivore), although it is speculated that the early sauropodomorphs may have been omnivorous. This animal, which was 4–6 metres (13–20 ft) long, had a long neck and tail, with a small head and slender body. On each of its forefeet, it bore a sharp thumb claw that was used in defense or feeding. Recent studies indicate that Massospondylus grew steadily throughout its lifespan, possessed air sacs similar to those of birds, and may have cared for its young.
 
As with all dinosaurs, much of the biology of Massospondylus, including its behavior, coloration, and physiology, remains unknown. However, recent studies have allowed for informed speculation on subjects such as growth patterns, diet, posture, reproduction, and respiration

10 Mamenchisaurus Facts

Wednesday, November 30, 2016

Mamenchisaurus by Sergey Krasovskiy

China’s overstuffed with awesome dinosaurs, and today we’re taking a look at one of their most famous.

1. MAMENCHISAURUS NECKS WOULD’VE MADE GIRAFFES FEEL SELF-CONSCIOUS

Mamenchisaurus necks approaching 30 feet in length have been documented, and one poorly-known species—M. sinocanadorum—is believed to have had nearly 50 feet separating its head from its shoulders. Let’s put that in perspective, shall we?  Regulation NFL goalposts have an 18’6” gap between their uprights. The largest (reliably) documented great white shark measured 19.5 feet from end to end. The average giraffe boasts a 6-foot neck. Meanwhile, yours is probably only around 10-12 inches long. How pathetic…

2. SOMETHING NASTY HAPPENED TO ONE POOR SPECIMEN’S TAIL

As paleontologist Dave Hone notes on his wonderful blog, a Mamenchisaurus skeleton that currently resides at China’s Chengdu University of Technology has an unnatural-looking growth above one of its tail vertebrae. This, he explains, was caused by either a broken and re-healed backbone injury or “an infection that spread inside the tail causing the build-up of ossified tissue.”

3. AN ESPECIALLY HUGE SPECIES WAS ASIA’S LARGEST DINOSAUR

We still don’t know which dino was the world’s all-time biggest, but at an estimated 115 feet in length, Mamenchisaurus sinocanadorum clearly deserves to be part of this discussion.

4. ANOTHER SPECIES HAD AN ODD SPINAL COLUMN

Paleo-artist Gregory S. Paul points out that the vertebrae above this dinosaur’s hips are fused together in a strange, V-shaped orientation. Therefore, M. youngimight have had to permanently hold its tail at an upturned, awkward-looking 20-degree angle.

5. MAMENCHISAURUS FEATURED “SPATULA-SHAPED” TEETH

These broad chompers were ideal for gathering bundles of leaves in huge gulps, unlike the pencil-shaped teeth of such massive herbivores as Diplodocus, a dino which nimbly stripped them from narrow branches.

6. AT LEAST ONE VARIETY HAD A CLUBBED TAIL

Although Mamenchisaurus hochuanensis rocked a small, bony knob at the end of its tail, some scientists claim that this thing would’ve been practically useless as a weapon. Interestingly, M. houchanensis was far from the only Asian sauropod (“long-necked dino”) to have had one. Omeisaurus and Shunosaurus were also card-carrying members of the prestigious “Tail-Club Club”.

7. THE CZECH REPUBLIC BOASTS AN ANIMATRONIC MAMENCHISAURUS

Next time you’re in Prague, be sure to visit this guy at the Harfa DinoPark (and don’t forget the kids)!

Speaking of cool displays, NYC’s American Museum of Natural History temporarily housed some reconstructed Mamenchisaurus organs. Sadly, this exhibit’s no longer in town, but feel free to check out several neat photos here.

8. IT HAD HUGE “NECK RIBS”

Mamenchisaurus hochuanensis Young & Zhao, 1972 sauropod dinosaur from the Jurassic of China (public display, Field Museum of Natural History, Chicago, Illinois, USA) (cast based on on CCG V 20401, Chengdu College of Geology (Chengdu Institute of Geology/Chengdu University of Technology), Chengdu, Sichuan, China). This sauropod dinosaur had a 22 meter long body (~72 feet) and a hyperelongated neck (>9 meters long – about 31 feet). Author James St. John

Take a gander at this picture. Notice those long, pointy things on the bottom of this Mamenchisaurus’ neck? They’re called “cervical ribs,” and they probably acted as a load-bearing mechanism. However, these would have also cost the dino some flexibility in that area. Alas, life frequently demands such trade-offs.

9. ACCORDING TO ONE STUDY, MAMENCHISAURUS PREFERRED LOW-LYING VEGETATION

In 2013, an international paleontological team took a good, hard look at Mamenchisaurus youngi and its magnificent vertebrae. Their research concluded that, based on its relative stiffness, M. youngi “had a nearly straight, near horizontal neck posture and browsed at low or medium heights.”

10. MAMENCHISAURUS MAY HAVE PLAYED A PART IN THE HISTORY OF CHINESE MEDICINE

Are mythical dragons and long-gone dinosaurs really one and the same? Written sometime during the Jin Dynasty (265-317 C.E.), an invaluable book called The Chronicles of Huayang records the discovery of “dragon bones” in what is now China’s Sichuan Province. Jurassic fossil deposits—including a few which have produced Mamenchisaurus material—are widespread throughout the area. Perhaps this period’s dinosaurs helped give rise to the legendary, fire-breathing reptiles of Chinese folklore.

Furthermore, it was once widely believed that dragons harbored some medicinal qualities. In fact, as recently as 2006, dinosaur fossils were still being sold as “dragon bones” (at around 25 cents per pound), mashed up, and “boiled with other ingredients and fed to children to treat dizziness and leg cramps.” Ask your doctor if Mamenchisaurus is right for you!

Original article by www.mentalfloss.com

Mamenchisaurus

Wednesday, November 30, 2016

Mamenchisaurus skeleton

Mamenchisaurus is a sauropod dinosaur genus including several species, known for their remarkably long necks which made up half the total body length. It is known from numerous species which ranged in time from 160 to 145 million years ago, from the Oxfordian to Tithonian ages of the late Jurassic Period of China, and the largest species may have reached 35 m (115 ft) in length and possibly weighed 50 to 75 tons.
 
The longest neck of any animal known to us from any time belonged to Mamenchisaurus. It made up half the animal’s total length. Reaching perhaps 49 feet (15 m) long, this incredible structure was supported by 19 vertebrae – no other dinosaur had as many neck vertebrae. Because these vertebrae were hollow – and in places the bone was as thin as egg shells – the neck was very light. Long bony struts running between the neck vertebrae would have limited its flexibility, and many reconstructions of Mamenchisaurus show it with the neck held straight as a ramrod. Some of these bony struts would have overlapped three or four vertebrae.

Mamenchisaurus Species Scale by Steveoc86

Mamenchisaurus was first discovered in 1952 on the construction site of the Yitang Highway in Sichuan, China. The partial skeleton fossil was then studied, and named Mamenchisaurus constructus in 1954, by the renowned Chinese paleontologist Professor C. C. Young. The type specimen had an incomplete neck with 14 vertebra preserved and none of these were complete. M. constructus has been estimated around 13 m (43 ft) and 15 m (49 ft) in length.

Only a few skull fragments have been found of Mamenchisaurus. These suggest that it had a relatively short snout with robust, blunt teeth in the front and along the sides of the mouth. The particularly heavy teeth give a clue to its diet. These teeth could have dealt with the coarser, harder parts of plants and would have been especially good for shredding cycads and other fibrous fronds.

Artist’s impression of M. hochuanensis by Dimitri Bogdanov
Although superficially Mamenchisaurus looks similar to North American sauropods such as Diplodocus and Apatosaurus, we now think that it was part of a group of sauropods unique to Asia. By the late Jurassic, the early Atlantic Ocean had become wide enough to restrict the flow of animals between North America and Europe and, although Europe and Asia were connected by land, there were deserts and mountain ranges that would have restricted the movement of large land animals from east to west.

Species

  • M. anyuensis He, Yang, Cai, Li & Liu, 1996. Approximately 21 meters (69 ft) in length. Known from both the Suining Formation and Penglaizhen Formation.
  • M. constructus Young, 1954: (Type species) The holotype specimen, represented by a partial skeleton that was 13 m (43 ft) long.
  • M. hochuanensis Young & Zhao, 1972: Four partial skeletons. Known from Shaximiao Formation and 22 m (72 ft) in length.
  • M. jingyanensis Zhang, Li & Zeng, 1998. Known from Shaximiao Formation and estimated between 20 to 26 metres (66 to 85 ft) in length.
  • M. sinocanadorum D. Russell & Zheng, 1993: Partial skull, isolated bones (type), referred, nearly complete skeleton. Known from the upper part of the Shishugou Formation (about 160 Ma ago), it may include one of the largest complete dinosaur specimens known, measuring 35 metres (115 ft) in length.
  • M. youngi Pi, Ouyang & Ye, 1996: Mamenchisaurus youngi (pronunciation YOUNG-eye) was unearthed in Xinmin County, Zigong City in Sichuan Province, China, in 1989. The species was named in honour of Young. It was a very complete and articulated specimen preserving all the vertebra from the head up until the 8th tail vertebra. It had 18 neck vertebra. At 16 meters (52 ft) long with a 6.5-meter (21 ft) neck, is relatively small among various species of Mamenchisaurus.

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