DINOSAURICON E
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- Echinodon Echinodon was een geslacht van plantenetende dinosauriërs behorend tot de Ornithischia, die tijdens het Late Jura leefde in het gebied van het huidige Engeland. De typesoort is Echinodon becklesii. syn : Saurechinodon Herbivore, Quadrupedal Ornithischia Suborder: Thyreophora? Family: Scelidosauridae? H 0.3 meters L 0.6 meters Late Jurassic
Discovered in England and described by Sir Richard Owen in 1861, Echinodon was once considered to be a fabrosaurid, a family name that has now been abandoned. It may have been related to Scutellosaurus, a plant-eater with small bony armor plates on its back. Evidence suggests that armor found in England in 1879 and thought to belong to a lizard, may belong to Echinodon, thus moving it into the mostly quadrupedal Thyreophora suborder of ornithischians.
http://scienceblogs.com/tetrapodzoology/2007/05/24/galve-european-spinosaurines-c/ http://qilong.wordpress.com/2012/10/08/pegomastax-and-the-echinodonts/
NHMUK 48215b, a paralectotype dentary referred to Echinodon becklesii (Owen, 1861). AfterSereno, 2012.
It was a theropod closely related to Torvosaurus, and may, in fact, be a junior synonym of that genus. Its fossils, including a partial skeleton, were found at Como Bluff, Wyoming.
http://dinosaurss.blog.cz/1105/edmarka
http://tolweb.org/NodosauridaeEdmontonia (meaning “From the Edmonton Formation”) was an armoured dinosaur, a part of the nodosaur family from the Late Cretaceous Period. It is named after the Edmonton Formation (now the Horseshoe Canyon Formation), the unit of rock it was found in. was bulky and tank-like at roughly 6.6 m (22 ft) long and 2m (6 ft) high.[citation needed] It had small, ridged bony plates on its back and head and many sharp spikes along its back and tail. The four largest spikes jutted out from the shoulders on each side, two of which were split into subspines in some specimens. Its skull had a pear-like shape when viewed from above.(information from Wikipedia.org
De lange schedels van een Edmontosaurus en een paard; beide hebben een lange schedel en grote maalkiezen
E. REGALIS
Late Cretaceous, Ornithischia : Ornithopoda : Hadrosauridae : Hadrosaurinae : Edmontosaurus: Edmontosaurus regalis
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Hanenkam ontdekt
13 december 2013 Caroline Kraaijvanger 1
Wetenschappers hebben in Canada een bijzondere ontdekking gedaan. Ze troffen er de gemummificeerde resten van een eendensnaveldinosaurus met een hanenkam aan. Het bewijst voor het eerst dat deze dino’s een kleurige kam op de kop hadden die in veel opzichten overeenkomsten vertoont met de moderne hanenkam.
Het is niet ongewoon dat dinosaurussen worden teruggevonden met een bijzondere structuur op de kop. Denk maar eens aan de Triceratops met hoorns op de kop en dat enorme schild dat zijn kwetsbare nek beschermde. Maar dat zijn stuk voor stuk botstructuren. Een dinosaurus met een vlezige structuur op de kop is nog nooit ontdekt.
Gemummificeerd
Tot nu dan. In Canada troffen de onderzoekers de resten van een gemummificeerde eendensnaveldinosaurus aan. Het gaat om een Edmontosaurus regalis: een soort waar al diverse fossiele resten van zijn teruggevonden. En toch is deze vondst bijzonder. “We hebben reeds heel veel schedels van de Edmontosaurus gevonden, maar geen enkele vertoont aanwijzingen dat ze een grote, vlezige kam op de kop hadden,” vertelt onderzoeker Phil Bell. En dat is ook goed te verklaren. Omdat er geen bot in de kam zit, fossiliseert deze niet. Dat onderzoekers de hanenkam nu gedetecteerd hebben, is dan ook puur te danken aan het feit dat de Edmontosaurus die de onderzoekers ontdekten, gemummificeerd was.
De vondst trekt het uiterlijk van diverse dino’s waarmee we juist zo vertrouwd zijn geraakt, in twijfel en is volgens Bell, erg belangrijk. Normaal gesproken fossiliseert een vleesachtige structuur zoals een hanenkam namelijk niet.
“Het is alsof we voor het eerst hebben ontdekt dat olifanten slurven hebben. We hebben veel schedels van Edmontosaurussen gevonden, maar nooit eerder waren er aanwijzingen dat ze een vlezige kam op hun hoofd hadden.”
Bell vermoedt dat ook andere dinosauriërs hanenkammen hadden. “Er is geen reden om aan te nemen dat andere vreemde vlezige structuren niet aanwezig waren op heel veel andere dinosaurussen, waaronder(bijvoorbeld ) de T. rex of de Triceratops,” stelt Bell.
Het is nog onduidelijk waar de hanenkam van de dinosaurussen voor diende. Vergelijkbare structuren komen ook voor bij moderne dieren zoals kameleons en hanen en hagedissen en dienen meestal om indruk te maken op mogelijke seksuele partners en ze zodoende te versieren . Mogelijk gold dat ook voor de dinosaurus.
Bronmateriaal:
Tijdschrift Current Biology.
Nieuwssite Phys.org.
“Surprise: Duck-Billed Dinosaurs Had Fleshy ‘Cocks Comb’” – Cell Press (via Sciencedaily.com).
De afbeelding bovenaan dit artikel is gemaakt door Julius Csotonyi © Bell, Fanti, Currie, Arbour, Current Biology.
De afbeelding bovenaan dit artikel is gemaakt door Julius Csotonyi © Bell, Fanti, Currie, Arbour, Current Biology.
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Edmontosaurus is a genus of crestless (?) duck-billed dinosaur.
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The fossils of this animal have been found in rocks of western North America that date from the late Campanian stage to the end of the Maastrichtian stage of the Cretaceous Period, between 73 and 65.5 million years ago. It was one of the last non-avian dinosaurs, and live alongsideTriceratops and Tyrannosaurusshortly before the Cretaceous–Tertiary extinction event.Edmontosaurus was one of the largest hadrosaurids, measuring up to 13 meters (43 ft) long and weighing around 4.0 metric tons (4.4 short tons). It is known from several well-preserved specimens that include not only bones, but in some cases extensive skin impressions and possible gut contents. It is classified as a hadrosaurine hadrosaurid (those hadrosaurids which lacked a fossilised hollow crest), and was closely related to Anatotitan,(if not a synonym.)
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Edmontosaurus has a lengthy and complicated taxonomic history dating to the late 19th century. Various species classified with genera such as Claosaurus, Thespesius, Trachodon, and the well-known but now defunct genus Anatosaurus are now regarded as belonging to Edmontosaurus. The first fossils named Edmontosaurus were discovered in southern Alberta, Canada, in what used to be called the lower Edmonton Formation. The type species, E. regalis, was named by Lawrence Lambe in 1917, although several other species that are now classified in Edmontosaurus were named earlier. The best known of these is E. annectens, originally named by Othniel Charles Marsh in 1892 as Claosaurus annectens and known for many years as Anatosaurus annectens. A third smaller species, E. saskatchewanensis, is also known. The name Edmontosaurus means “Edmonton lizard”; the genus was named after the Edmonton Formation, now known as the Horseshoe Canyon Formation.Edmontosaurus was widely distributed across western North America. The distribution of Edmontosaurus fossils suggests that it preferred coasts and coastal plains. It was a herbivore that could move on both two legs and four. Because it is known from several bone beds, Edmontosaurus is thought to have lived in groups, and may have been migratory as well. The wealth of fossils has allowed researchers to study its paleobiology in detail, including its brain, how it may have fed, and its injuries and pathologies, such as evidence for a tyrannosaur attack on one edmontosaur specimen.
with or without crest ?
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Description
Edmontosaurus has been described in detail from several specimens. Like other hadrosaurids, it was a bulky animal with a long, laterally flattened tail and a head with an expanded, duck-like beak. The skull had no hollow or solid crest, unlike many other hadrosaurids. The fore legs were not as heavily built as the hind legs, but were long enough to be used in standing or movement. Edmontosaurus was among the largest hadrosaurids: depending on the species, a fully grown adult could have been 9 meters (30 ft) long, and some of the larger specimens reached the range of 12 meters (39 ft) to 13 meters (43 ft) long. Its weight was on the order of 4.0 metric tons (4.4 short tons). At the present, E. regalis is the largest species, although its status may be challenged if the large hadrosaurid Anatotitan copei is shown to be the same as Edmontosaurus annectens, as put forward by Jack Horner and colleagues in 2004 (this remains to be tested by other authors). The type specimen of E. regalis, NMC 2288, is estimated as 9 to 12 meters (30 to 39 ft) long. E. annectens was somewhat shorter. Two well-known mounted skeletons, USNM 2414 and YPM 2182, measure 8.00 meters (26.25 ft) long and 8.92 meters (29.3 ft) long, respectively. However, there is at least one report of a much larger potential E. annectens specimen, almost 12 meters (39 ft) long. E. saskatchewanensis was smaller yet, with its full length estimated as 7 to 7.3 meters (23 to 24.0 ft).
Edmontosaurus has been described in detail from several specimens. Like other hadrosaurids, it was a bulky animal with a long, laterally flattened tail and a head with an expanded, duck-like beak. The skull had no hollow or solid crest, unlike many other hadrosaurids. The fore legs were not as heavily built as the hind legs, but were long enough to be used in standing or movement. Edmontosaurus was among the largest hadrosaurids: depending on the species, a fully grown adult could have been 9 meters (30 ft) long, and some of the larger specimens reached the range of 12 meters (39 ft) to 13 meters (43 ft) long. Its weight was on the order of 4.0 metric tons (4.4 short tons). At the present, E. regalis is the largest species, although its status may be challenged if the large hadrosaurid Anatotitan copei is shown to be the same as Edmontosaurus annectens, as put forward by Jack Horner and colleagues in 2004 (this remains to be tested by other authors). The type specimen of E. regalis, NMC 2288, is estimated as 9 to 12 meters (30 to 39 ft) long. E. annectens was somewhat shorter. Two well-known mounted skeletons, USNM 2414 and YPM 2182, measure 8.00 meters (26.25 ft) long and 8.92 meters (29.3 ft) long, respectively. However, there is at least one report of a much larger potential E. annectens specimen, almost 12 meters (39 ft) long. E. saskatchewanensis was smaller yet, with its full length estimated as 7 to 7.3 meters (23 to 24.0 ft).
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Skull
The skull of a fully grown Edmontosaurus was around a meter (or yard) long, with E. regalis falling on the longer end of the spectrum and E. annectens falling on the shorter end. The skull was roughly triangular in profile, with no bony cranial crest. Viewed from above, the front and rear of the skull were expanded, with the broad front forming a duck-bill or spoon-bill shape. The beak was toothless, and both the upper and lower beaks were extended by keratinous material. Substantial remains of the keratinous upper beak are known from the “mummy” kept at the Senckenberg Museum. In this specimen, the preserved nonbony part of the beak extended for at least 8 centimeters (3.1 in) beyond the bone, projecting down vertically. The nasal openings of Edmontosaurus were elongate and housed in deep depressions surrounded by distinct bony rims above, behind, and below. In at least one case (the Senckenberg specimen), rarely preserved sclerotic rings were preserved in the eye sockets. Another rarely seen bone, the stapes (the reptilian ear bone), has also been seen in a specimen of Edmontosaurus.
The skull of a fully grown Edmontosaurus was around a meter (or yard) long, with E. regalis falling on the longer end of the spectrum and E. annectens falling on the shorter end. The skull was roughly triangular in profile, with no bony cranial crest. Viewed from above, the front and rear of the skull were expanded, with the broad front forming a duck-bill or spoon-bill shape. The beak was toothless, and both the upper and lower beaks were extended by keratinous material. Substantial remains of the keratinous upper beak are known from the “mummy” kept at the Senckenberg Museum. In this specimen, the preserved nonbony part of the beak extended for at least 8 centimeters (3.1 in) beyond the bone, projecting down vertically. The nasal openings of Edmontosaurus were elongate and housed in deep depressions surrounded by distinct bony rims above, behind, and below. In at least one case (the Senckenberg specimen), rarely preserved sclerotic rings were preserved in the eye sockets. Another rarely seen bone, the stapes (the reptilian ear bone), has also been seen in a specimen of Edmontosaurus.
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The Senckenberg mummy
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Skull of the Senckenberg Edmontosaurus mummyin left lateral view.
Teeth were present only in the maxillae (upper cheeks) and dentaries (main bone of the lower jaw). The teeth were continually replaced, taking about half a year to form. They grew in columns, with an observed maximum of six in each, and the number of columns varied based on the animal’s size. Known column counts for the various species are: 51 to 53 columns per maxilla and 48 to 49 per dentary (teeth of the upper jaw being slightly narrower than those in the lower jaw) for E. regalis; 43 columns per maxilla and 36 per dentary for E. annectens; and 52 and 44 for E. saskatchewanensis.
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Postcranial skeleton
The number of vertebrae differs between specimens. E. regalis had thirteen neck vertebrae, eighteen back vertebrae, nine hip vertebrae, and an unknown number of tail vertebrae. A specimen once identified as belonging to Anatosaurus edmontoni (now considered to be the same as E. annectens) is reported as having an additional back vertebra and 85 tail vertebrae, with an undisclosed amount of restoration. Other hadrosaurids are only reported as having 50 to 70 tail vertebrae, so this appears to have been an overestimate. The anterior back was curved toward the ground, with the neck flexed upward and the rest of the back and tail held horizontally. Most of the back and tail were lined by ossified tendons arranged in a latticework along the neural spines of the vertebrae. This condition has been described as making the back and at least part of the tail “ramrod” straight.
The number of vertebrae differs between specimens. E. regalis had thirteen neck vertebrae, eighteen back vertebrae, nine hip vertebrae, and an unknown number of tail vertebrae. A specimen once identified as belonging to Anatosaurus edmontoni (now considered to be the same as E. annectens) is reported as having an additional back vertebra and 85 tail vertebrae, with an undisclosed amount of restoration. Other hadrosaurids are only reported as having 50 to 70 tail vertebrae, so this appears to have been an overestimate. The anterior back was curved toward the ground, with the neck flexed upward and the rest of the back and tail held horizontally. Most of the back and tail were lined by ossified tendons arranged in a latticework along the neural spines of the vertebrae. This condition has been described as making the back and at least part of the tail “ramrod” straight.
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The ossified tendons are interpreted as having strengthened the vertebral column against gravitational stress, incurred through being a large animal with a horizontal vertebral column otherwise supported mostly by the hind legs and hips.The shoulder blades were long flat blade-like bones, held roughly parallel to the vertebral column. The hips were composed of three elements each: an elongate ilium above the articulation with the leg, an ischium below and behind with a long thin rod, and a pubis in front that flared into a plate-like structure.
The structure of the hip hindered the animal from standing with its back erect, because in such a position the thigh bone would have pushed against the joint of the ilium and pubis, instead of pushing only against the solid ilium. The nine fused hip vertebrae provided support for the hip.
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The fore legs were shorter and less heavily built than the hind legs. The upper arm had a large deltopectoral crest for muscle attachment, while the ulna and radius were slim. The upper arm and forearm were similar in length. The wrist was simple, with only two small bones. Each hand had four fingers, with no thumb (first finger). The index second, third, and fourth fingers were approximately the same length and were united in life within a fleshy covering. Although the second and third finger had hoof-like unguals, these bones were also within the skin and not apparent from the outside. The little finger diverged from the other three and was much shorter. The thigh bone was robust and straight, with a prominent flange about halfway down the posterior side. This ridge was for the attachment of powerful muscles attached to the hips and tail that pulled the thighs (and thus the hind legs) backward and helped maintain the use of the tail as a balancing organ. Each foot had three toes, with no big toe or little toe. The toes had hoof-like tips.
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Skin
AMNH 5060: a well preserved specimen of Edmontosaurus annectens
Multiple specimens of Edmontosaurus have been found with preserved skin impressions. Several have been well-publicized, such as the “Trachodon mummy” of the early 20th century, and the specimen nicknamed “Dakota”, the latter apparently including remnant organic compounds from the skin. Because of these finds, the scalation of Edmontosaurus is known for most areas of the body.
Multiple specimens of Edmontosaurus have been found with preserved skin impressions. Several have been well-publicized, such as the “Trachodon mummy” of the early 20th century, and the specimen nicknamed “Dakota”, the latter apparently including remnant organic compounds from the skin. Because of these finds, the scalation of Edmontosaurus is known for most areas of the body.
Skin impression from the abdomen of Edmontosaurus annectens
Skin impression of the specimen nicknamed “Dakota”, which was found in 1999
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A large patch of fossilized dinosaur skin. The stripe of larger scales probably ran along the back of the embryo.
Luis Chiappe | Lorraine Meeker AMNH
Luis Chiappe | Lorraine Meeker AMNH
AMNH 5060, the “Trachodon mummy” (so-called because it appears to be a fossil of a natural mummy), is now recognized as a specimen of E. annectens.
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It was found to have skin impressions over the snout, much of the neck and torso, and parts of the arms and legs. The tail and part of the legs eroded before collection, so these areas are unknown for the specimen.
Additionally, some areas with skin impressions, such as sections associated with the neck ridge (see below) and hands, were accidentally removed during preparation of the specimen.
The specimen is thought to have desiccated in a dry stream bed, probably on or near a point bar. The circumstances of the location and preservation of the body suggest that the animal died during a prolonged drought, perhaps from starvation. The desiccated carcass was eventually buried in a sudden flood, surrounded by sediment that had enough fine particles to make a cast of the epidermal structures.The epidermis was thin, and the scalation composed of small nonoverlapping scales, as seen in the Gila monster.
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Two general types of scales were present over most of the body: small pointed or convex tubercles, 1 to 3 millimeters (0.039 to 0.12 in) in diameter with no definite arrangement (ground tubercles); and larger, flat polygonal tubercles (pavement tubercles) typically less than 5 millimeters (0.20 in) in diameter, but up to 10 millimeters (0.39 in) over the forearm. The pavement tubercles were grouped into clusters separated by ground tubercles, with transitional scales between the two types. Over most of the body, the pavement tubercles were arranged in circular or oval clusters, while near the shoulder on the upper arm, they formed strips roughly parallel to each other and the shoulder blade. Generally, clusters were larger on the upper surfaces of the body and smaller on the underside. Clusters up to 50 centimeters (20 in) in length were present above the hips.The only impressions from the head came from the large opening for the nostrils. Instead of tubercle impressions, there were impressions of folded soft tissue, with a deeper area at the anterior end of the opening that may have been the approximate location of the nostril itself. The neck and back had a soft ridge or frill running down the midline, with a row of oval tubercle clusters arranged above the spines of the vertebrae. The total height of the ridge on AMNH 5060 is not known, nor the disposition of its upper border, as the upper extremity was prepared away. The ridge was at least 8 centimeters (3.1 in) tall, and was folded and creased to permit movement. Osborn proposed that it was tall enough for another row of clusters.The forearms had the largest tubercles, arranged in single large clusters that covered the leading surfaces. The hands were covered in small pavement tubercles in a soft-tissue structure than enclosed the three central fingers; not even the tips were exposed. Osborn interpreted this as a paddle for swimming. Robert T. Bakker later reinterpreted it as a soft-tissue pad for walking, analogous to that of a camel. Like the forearm, the shin had large tubercles. The scalation of the rest of the leg is not presently known, although impressions on a specimen of the crested hadrosaurid Lambeosaurus suggest that the thighs were under the skin of the body, like modern birds.The tail of AMNH 5060 was not present, but other specimens have filled in some details for that area.
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Skin impressions from a partial tail belonging to either Edmontosaurus or its close relative Anatotitan, recovered from the Hell Creek Formation of Montana, show a segmented ridge above the vertebrae.
The ridge was about 8.0 centimeters (3.1 in) tall, with the segments being about 5.0 centimeters (2.0 in) long and 4.5 centimeters (1.8 in) high, spaced 1.0 centimeter (0.39 in) apart, with one segment to a vertebra. Another tail, this time pertaining to a juvenile E. annectens, had fossilized impressions including tubercles as well as previously unseen skin textures.
These impressions included elliptical overlapping scales, grooved scales, and a “9 cm by 10 cm trapezoidal horn-like structure”.
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Failed attack
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Classification
Edmontosaurus was a hadrosaurid (a duck-billed dinosaur), a member of a family of dinosaurs which to date are known only from the Late Cretaceous. It is classified within the Hadrosaurinae, a clade of hadrosaurids which lacked hollow crests. Other members of the group include Brachylophosaurus, Gryposaurus, Lophorhothon, Maiasaura, Naashoibitosaurus, Prosaurolophus, and Saurolophus. It was either closely related to or the same as Anatotitan, another large hadrosaurid from various latest Cretaceous formations of western North America. The giant Chinese hadrosaurine Shantungosaurus is also anatomically similar to Edmontosaurus; M. K. Brett-Surman found the two to differ only in details related to the greater size of Shantungosaurus, based on what had been described of the latter genus.While the status of Edmontosaurus as a hadrosaurine has not been challenged, its exact placement within the clade is uncertain. Early phylogenies, such as that presented in R. S. Lull and Nelda Wright’s influential 1942 monograph, had Edmontosaurus and various species of Anatosaurus (most of which would be later reevaluated as additional species or specimens of Edmontosaurus) as one lineage among several lineages of “flat-headed” hadrosaurs. One of the first analyses using cladistic methods found it to be linked with Anatotitan and Shantungosaurus in an informal “edmontosaur” clade, which was paired with the spike-crested “saurolophs” and more distantly related to the “brachylophosaurs” and arch-snouted “gryposaurs”. A 2007 study by Terry Gates and Scott Sampson found broadly similar results, in that Edmontosaurus remained close to Saurolophus and Prosaurolophus and distant from Gryposaurus, Brachylophosaurus, and Maiasaura.
Edmontosaurus was a hadrosaurid (a duck-billed dinosaur), a member of a family of dinosaurs which to date are known only from the Late Cretaceous. It is classified within the Hadrosaurinae, a clade of hadrosaurids which lacked hollow crests. Other members of the group include Brachylophosaurus, Gryposaurus, Lophorhothon, Maiasaura, Naashoibitosaurus, Prosaurolophus, and Saurolophus. It was either closely related to or the same as Anatotitan, another large hadrosaurid from various latest Cretaceous formations of western North America. The giant Chinese hadrosaurine Shantungosaurus is also anatomically similar to Edmontosaurus; M. K. Brett-Surman found the two to differ only in details related to the greater size of Shantungosaurus, based on what had been described of the latter genus.While the status of Edmontosaurus as a hadrosaurine has not been challenged, its exact placement within the clade is uncertain. Early phylogenies, such as that presented in R. S. Lull and Nelda Wright’s influential 1942 monograph, had Edmontosaurus and various species of Anatosaurus (most of which would be later reevaluated as additional species or specimens of Edmontosaurus) as one lineage among several lineages of “flat-headed” hadrosaurs. One of the first analyses using cladistic methods found it to be linked with Anatotitan and Shantungosaurus in an informal “edmontosaur” clade, which was paired with the spike-crested “saurolophs” and more distantly related to the “brachylophosaurs” and arch-snouted “gryposaurs”. A 2007 study by Terry Gates and Scott Sampson found broadly similar results, in that Edmontosaurus remained close to Saurolophus and Prosaurolophus and distant from Gryposaurus, Brachylophosaurus, and Maiasaura.
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However, the most recent review of Hadrosauridae, by Jack Horner and colleagues (2004), came to a noticeably different result: Edmontosaurus was nested between Gryposaurus and the “brachylophosaurs”, and distant from Saurolophus. The discrepancies are complicated by the relative lack of work on hadrosaurine evolutionary relationships.
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Discovery and history
Edmontosaurus has had a long and complicated history in paleontology, having spent decades with various species classified in other genera. Its taxonomic history intertwines at various points with the genera Agathaumas, Anatosaurus, Anatotitan, Claosaurus, Hadrosaurus, Thespesius, and Trachodon, and references predating the 1980s typically use Anatosaurus, Claosaurus, Thespesius, or Trachodon for edmontosaur fossils (excluding those assigned to E. regalis), depending on author and date. Although Edmontosaurus was only named in 1917, its oldest well-supported species (E. annectens) was named in 1892 as a species of Claosaurus, and scrappier fossils that may belong to it were described as long ago as 1871.The first described remains that may belong to Edmontosaurus were named Trachodon atavus in 1871 by Edward Drinker Cope. This species was assessed without comment as a synonym of Edmontosaurus regalis in two reviews, although atavus predates regalis by several decades. In 1874 Cope named but did not describe Agathaumas milo for a sacral vertebra and shin fragments from the late Maastrichtian-age Upper Cretaceous Laramie Formation of Colorado. Later that same year, he described these bones under the name Hadrosaurus occidentalis. The bones are now lost. As with Trachodon atavus, Agathaumas milo has been assigned without comment to Edmontosaurus regalis in two reviews, although predating regalis by several decades. Neither species has attracted much attention; both are absent from Lull and Wright’s 1942 monograph, for example. A third obscure early species, Trachodon selwyni, described by Lawrence Lambe in 1902 for a lower jaw from what is now known as the Dinosaur Park Formation of Alberta, was erroneously described by Glut (1997) as having been assigned to Edmontosaurus regalis by Lull and Wright. It was not, instead being designated “of very doubtful validity.”
Edmontosaurus has had a long and complicated history in paleontology, having spent decades with various species classified in other genera. Its taxonomic history intertwines at various points with the genera Agathaumas, Anatosaurus, Anatotitan, Claosaurus, Hadrosaurus, Thespesius, and Trachodon, and references predating the 1980s typically use Anatosaurus, Claosaurus, Thespesius, or Trachodon for edmontosaur fossils (excluding those assigned to E. regalis), depending on author and date. Although Edmontosaurus was only named in 1917, its oldest well-supported species (E. annectens) was named in 1892 as a species of Claosaurus, and scrappier fossils that may belong to it were described as long ago as 1871.The first described remains that may belong to Edmontosaurus were named Trachodon atavus in 1871 by Edward Drinker Cope. This species was assessed without comment as a synonym of Edmontosaurus regalis in two reviews, although atavus predates regalis by several decades. In 1874 Cope named but did not describe Agathaumas milo for a sacral vertebra and shin fragments from the late Maastrichtian-age Upper Cretaceous Laramie Formation of Colorado. Later that same year, he described these bones under the name Hadrosaurus occidentalis. The bones are now lost. As with Trachodon atavus, Agathaumas milo has been assigned without comment to Edmontosaurus regalis in two reviews, although predating regalis by several decades. Neither species has attracted much attention; both are absent from Lull and Wright’s 1942 monograph, for example. A third obscure early species, Trachodon selwyni, described by Lawrence Lambe in 1902 for a lower jaw from what is now known as the Dinosaur Park Formation of Alberta, was erroneously described by Glut (1997) as having been assigned to Edmontosaurus regalis by Lull and Wright. It was not, instead being designated “of very doubtful validity.”
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More recent reviews of hadrosaurids have concurred.The first well-supported species of Edmontosaurus was named in 1892 as Claosaurus annectens by Othniel Charles Marsh. This species is based on USNM 2414, a skull and skeleton, with a second skull and skeleton, YPM 2182, designated the paratype. Both were collected in 1891 by John Bell Hatcher from the late Maastrichtian-age Upper Cretaceous Lance Formation of Niobrara County (then part of Converse County), Wyoming. This species has some historical footnotes attached: it is among the first dinosaurs to receive a skeletal restoration, and is the first hadrosaurid so restored; and YPM 2182 and UNSM 2414 are, respectively, the first and second essentially complete mounted dinosaur skeletons in the United States. YPM 2182 was put on display in 1901, and USNM 2414 in 1904.Because of the incomplete understanding of hadrosaurids at the time, following Marsh’s death in 1897 Claosaurus annectens was variously classified as a species of Claosaurus, Thespesius o r Trachodon. Opinions varied greatly; textbooks and encyclopedias drew a distinction between the “Iguanodon-like” Claosaurus annectens and the “duck-billed” Hadrosaurus (based on remains now known under Anatotitan copei), while Hatcher explicitly identified C. annectens as synonymous with the hadrosaurid represented by those same duck-billed skulls.
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Hatcher’s revision, published in 1902, was sweeping: he considered almost all hadrosaurid genera then known as synonyms of Trachodon. This included Cionodon, Diclonius, Hadrosaurus, Ornithotarsus, Pteropelyx, and Thespesius, as well as Claorhynchus and Polyonax, fragmentary genera now thought to be horned dinosaurs. Hatcher’s work led to a brief consensus, until after 1910 new material from Canada and Montana showed a greater diversity of hadrosaurids than previously suspected.
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Charles W. Gilmore in 1915 reassessed hadrosaurids and recommended that Thespesius be reintroduced for hadrosaurids from the Lance Formation and rock units of equivalent age, and that Trachodon, based on inadequate material, should be restricted to a hadrosaurid from the older Judith River Formation and its equivalents. In regards to Claosaurus annectens, he recommended that it be considered the same as Thespesius occidentalis. His reinstatement of Thespesius for Lance-age hadrosaurids would have other consequences for the taxonomy of Edmontosaurus in the following decades.
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During this time frame (1902–1915), two additional important specimens of C. annectens were recovered. The first, the “Trachodon mummy” (AMNH 5060), was discovered in 1908 by Charles Hazelius Sternberg and his sons in Lance Formation rocks near Lusk, Wyoming. Sternberg was working for the British Museum of Natural History, but Henry Fairfield Osborn of the American Museum of Natural History was able to purchase the specimen for $2,000. The Sternbergs recovered a second similar specimen from the same area in 1910, not as well preserved but also found with skin impressions. They sold this specimen (SM 4036) to the Senckenberg Museum in Germany.
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Canadian discoveries
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Edmontosaurus itself was coined in 1917 by Lawrence Lambe for two partial skeletons found in the Edmonton Formation along the Red Deer River of southern Alberta, Canada. The Edmonton Formation lends the genus its name. These specimens came from the lower Edmonton Formation, now known as the Horseshoe Canyon Formation, which is slightly older than the rocks in which Claosaurus annectens was found. The type species, E. regalis (“regal,” or, more loosely, “king-sized”), is based on NMC 2288, consisting of a skull, articulated vertebrae up to the sixth tail vertebra, ribs, partial hips, an upper arm bone, and most of a hind limb. It was discovered in 1912 by Levi Sternberg.
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The second specimen, paratype NMC 2289, consists of a skull and skeleton lacking the beak, most of the tail, and part of the feet. It was discovered in 1916 by George F. Sternberg. Lambe found that his new dinosaur compared best to Diclonius mirabilis (specimens now assigned to Anatotitan copei), and drew attention to the size and robustness of Edmontosaurus.
Initially, Lambe only described the skulls of the two skeletons, but returned to the genus in 1920 to describe the skeleton of NMC 2289. The postcrania of the type specimen remains undescribed, still in its plaster jackets.Two more species that would come to be included with Edmontosaurus were named from Canadian remains in the 1920s, but both would initially be assigned to Thespesius. Gilmore named the first, Thespesius edmontoni, in 1924.
T. edmontoni also came from the Edmonton Formation. It was based on NMC 8399, another nearly complete skeleton lacking most of the tail. NMC 8399 was discovered on the Red Deer River in 1912 by a Sternberg party. Its forelimbs, ossified tendons, and skin impressions were briefly described in 1913 and 1914 by Lambe, who at first thought it was an example of a species he’d named Trachodon marginatus, but then changed his mind. The specimen became the first dinosaur skeleton to be mounted for exhibition in a Canadian museum. Gilmore found that his new species compared closely to what he called Thespesius annectens, but left the two apart because of details of the arms and hands.
He also noted that his species had more vertebrae than Marsh’s in the back and neck, but proposed that Marsh was mistaken in assuming that the annectens specimens were complete in those regions.
In 1926, Charles Mortram Sternberg named Thespesius saskatchewanensis for NMC 8509, a skull and partial skeleton from the Wood Mountain plateau of southern Saskatchewan. He had collected this specimen in 1921, from rocks that were assigned to the Lance Formation, now the Frenchman Formation. NMC 8509 included an almost complete skull, numerous vertebrae, partial shoulder and hip girdles, and partial hind limbs, representing the first substantial dinosaur specimen recovered from Saskatchewan. Sternberg opted to assign it to Thespesius because that was the only hadrosaurid genus known from the Lance Formation at the time.
At the time, T. saskatchewanensis was unusual because of its small size, estimated at 7 to 7.3 meters (23 to 24.0 ft) in length.Anatosaurus to the presentIn 1942, Lull and Wright attempted to resolve the complicated taxonomy of crestless hadrosaurids by naming a new genus, Anatosaurus, to take in several species that did not fit well under their previous genera. Anatosaurus, meaning “duck lizard”, because of its wide, duck-like beak (Latin anas = duck + Greek sauros = lizard), had as its type species Marsh’s old Claosaurus annectens. Also assigned to this genus were Thespesius edmontoni, T. saskatchewanensis, a large lower jaw that Marsh had named Trachodon longiceps in 1890, and a new species, Anatosaurus copei, for two skeletons on display at the American Museum of Natural History that had long been known as Diclonius mirabilis (or variations thereof). Thus, the various species became Anatosaurus annectens, A. copei, A. edmontoni, A. longiceps, and A. saskatchewanensis. Anatosaurus would come to be called the “classic duck-billed dinosaur.”This state of affairs persisted for several decades, until Michael K. Brett-Surman reexamined the pertinent material for his graduate studies in the 1970s and 1980s. He concluded that the type species of Anatosaurus, A. annectens, was actually a species of Edmontosaurus and that A. copei was different enough to warrant its own genus. Although theses and dissertations are not regarded as official publications by the International Commission on Zoological Nomenclature, which regulates the naming of organisms, his conclusions were known to other paleontologists, and were adopted by several popular works of the time. Brett-Surman and Ralph Chapman designated a new genus for A. copei (Anatotitan) in 1990. Of the remaining species, A. saskatchewanensis and A. edmontoni were assigned to Edmontosaurus as well, and A. longiceps went to Anatotitan, as either a second species or as a synonym of A. copei. Because the type species of Anatosaurus (A. annectens) was sunk into Edmontosaurus, the name Anatosaurus is abandoned as a junior synonym of Edmontosaurus.
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The conception of Edmontosaurus that emerged included three valid species: the type E. regalis, E. annectens (including Anatosaurus edmontoni, emended to edmontonensis), and E. saskatchewanensis.
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The debate about the proper taxonomy of the A. copei specimens continues to the present: returning to Hatcher’s argument of 1902, Jack Horner, David B. Weishampel, and Catherine Forster regarded Anatotitan copei as representing specimens of Edmontosaurus annectens with crushed skulls.
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In 2007 another “mummy” was announced; nicknamed “Dakota”, it was discovered in 1999 by Tyler Lyson, and came from the Hell Creek Formation of North Dakota.
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Species and distribution
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Edmontosaurus is currently regarded as having three valid species: type species E. regalis, E. annectens, and E. saskatchewanensis.
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UPDATE (211 ) Two valid species ( in North America )
Nearly all known complete Articulated Edmontosaurus skulls of North Amerika . E. regalis, E. annectens,//
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E. regalis is known from the Horseshoe Canyon Foron, St. Mary River Formation, and Scollard Formation of Alberta, the Hell Creek Formation of Montana, North Dakota, and South Dakota, the Lance Formation of South Dakota and Wyoming, and the Laramie Formation of Colorado, dating from the Maastrichtian Stage of the Late Cretaceous. At least a dozen individuals are known, including seven skulls with associated postcrania, and five to seven other skulls. Trachodon atavus and Agathaumas milo are potential synonyms.
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E. annectens was listed in the latest review as being present in the Scollard Formation of Alberta, the Hell Creek Formation of Montana and South Dakota, the Lance Formation of South Dakota and Wyoming, and the Laramie Formation of Colorado. It is limited to late Maastrichtian rocks, and is known from at least five skulls with postcrania. One author, Kraig Derstler, has described E. annectens as “perhaps the most perfectly-known dinosaur to date [1994].” Thespesius edmontoni or edmontonensis, Anatosaurus copei, and Trachodon longiceps were all regarded as synonyms of E. annectens in a 2004 review. T. edmontoni has usually been assigned to E. annectens since 1990, although the A. copei and T. longiceps synonymizations have not yet been tested by other authors. If they prove to belong to E. annectens, its total would increase by the five individuals assigned to A. copei and the lower jaw that is the holotype of T. longiceps (the number given for E. annectens in Horner et al. [2004] is incorrect, as it is unchanged from an earlier publication that did not consider A. copei and T. longiceps synonyms of E. annectens). The list of formations may be in error, depending on the formation that T. edmontoni comes from (it is not stated which part of the old Edmonton Formation it came from). T. edmontoni may be misassigned; James Hopson in 1975 proposed that it was a young E. regalis, and Nicolas Campione also found that its skull was indistinguishable from the contemporary E. regalis in a preliminary 2009 study. E. annectens differed from E. regalis by having a longer, lower, less robust skull. Although Brett-Surman regarded E. regalis and E. annectens as potentially representing males and females of the same species, all E. regalis specimens come from older formations than E. annectens specimens
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.E. saskatchewanensis is known from four or five individuals, mostly represented by skulls. It has only been found in the late Maastrichtian-age Frenchman Formation of Saskatchewan. It differs from the other two species in its smaller size. There has been little published on this species since its description, in comparison to the other two species. Preliminary work by Nicolas Campione have shown that it is probably a synonym of E. annectens, though more study is required.Additionally, there are many Edmontosaurus fossils that have not been identified to species. Remains that have not been assigned to a particular species (identified as E. sp.) may extend the range of the genus as far as the Prince Creek Formation of Alaska and the Javelina Formation of Texas.PaleoecologyEdmontosaurus was a wide-ranging genus in both time and space. The rock units from which it is known can be divided into two groups by age: the older Horseshoe Canyon and St. Mary River formations, and the younger Frenchman, Hell Creek, Lance, Laramie, and Scollard formations. The time span covered by the Horseshoe Canyon Formation and equivalents is also known as Edmontonian, and the time span covered by the younger units is also known as Lancian.
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The Edmontonian and Lancian time intervals had distinct dinosaur faunas.
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Edmontonian paleoecology
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The Edmontonian land vertebrate age is defined by the first appearance of Edmontosaurus regalis in the fossil record. Although sometimes reported as of exclusively early Maastrichtian age, the Horseshoe Canyon Formation was of somewhat longer duration. Deposition began approximately 73 million years ago, in the late Campanian, and ended between 68.0 and 67.6 million years ago. Edmontosaurus regalis is known from the lowest of five units within the Horseshoe Canyon Formation, but is absent from at least the second to the top. As many as three quarters of the dinosaur specimens from badlands near Drumheller, Alberta may pertain to Edmontosaurus. The Horseshoe Canyon Formation is interpreted as having a significant marine influence, due to an encroaching Western Interior Seaway, the shallow sea that covered the midsection of North America through much of the Cretaceous. E. regalis shared the setting with fellow hadrosaurids Hypacrosaurus and Saurolophus, hypsilophodont Parksosaurus, horned dinosaurs Montanoceratops, Anchiceratops, Arrhinoceratops, and Pachyrhinosaurus, pachycephalosaurid Stegoceras, ankylosaurid Euoplocephalus, nodosaurid Edmontonia, ostrich-mimics Ornithomimus and Struthiomimus, a variety of poorly known small theropods including troodontids and dromaeosaurids, and the tyrannosaurids Albertosaurus and Daspletosaurus. Edmontosaurus is found in coastal, near-marine settings, while Hypacrosaurus and Saurolophus are found in more continental lowlands. Edmontosaurus and Saurolophus are not usually found together. The typical edmontosaur habitat of this formation has been described as the back regions of bald cypress swamps and peat bogs on delta coasts. Pachyrhinosaurus also preferred this habitat to the floodplains dominated by Hypacrosaurus, Saurolophus, Anchiceratops and Arrhinoceratops. The Edmontonian-age coastal Pachyrhinosaurus-Edmontosaurus association is recognized as far north as Alaska.Lancian paleoecologyThe Lancian time interval was the last interval before the Cretaceous–Tertiary extinction event that eliminated non-avian dinosaurs. Edmontosaurus was one of the more common dinosaurs of the interval. Robert Bakker reports that it made up one-seventh of the large dinosaur sample, with most of the rest (five-sixths) made up of the horned dinosaur Triceratops. The coastal plain Triceratops–Edmontosaurus association, dominated by Triceratops, extended from Colorado to Saskatchewan. Typical dinosaur faunas of the Lancian formations where Edmontosaurus has been found also included the hypsilophodont Thescelosaurus, the rare hadrosaurid Anatotitan, the rare ceratopsids Nedoceratops (=”Diceratops”) and Torosaurus, pachycephalosaurids Pachycephalosaurus and Stygimoloch, the ankylosaurid Ankylosaurus, and the theropods Ornithomimus, Troodon, and Tyrannosaurus.The Hell Creek Formation, as typified by exposures in the Fort Peck area of Montana, has been interpreted as a flat forested floodplain, with a relatively dry subtropical climate that supported a variety of plants ranging from angiosperm trees, to conifers such as bald cypress, to ferns and ginkgos. The coastline was hundreds of kilometers or miles to the east. Stream-dwelling turtles and tree-dwelling multituberculate mammals were diverse, and monitor lizards as large as the modern Komodo dragon hunted on the ground. Triceratops was the most abundant large dinosaur, and Thescelosaurus the most abundant small herbivorous dinosaur. Edmontosaur remains have been collected here from stream channel sands, and include fossils from individuals as young as a meter- or yard-long infant. The edmontosaur fossils probably represent accumulations from groups on the move.The Lance Formation, as typified by exposures approximately 100 kilometers (62 mi) north of Fort Laramie in eastern Wyoming, has been interpreted as a bayou setting similar to the Louisiana coastal plain. It was closer to a large delta than the Hell Creek Formation depositional setting to the north and received much more sediment. Tropical araucarian conifers and palm trees dotted the hardwood forests, differentiating the flora from the northern coastal plain. The climate was humid and subtropical, with conifers, palmettos, and ferns in the swamps, and conifers, ash, live oak, and shrubs in the forests. Freshwater fish, salamanders, turtles, diverse lizards, snakes, shorebirds, and small mammals lived alongside the dinosaurs. Small dinosaurs are not known in as great of abundance here as in the Hell Creek rocks, but Thescelosaurus once again seems to have been relatively common. Triceratops is known from many skulls, which tend to be somewhat smaller than those of more northern individuals. The Lance Formation is the setting of two edmontosaur “mummies”.Brain and nervous system
A 1905 chart showing the relatively small brains of a Triceratops (top) and EdmontosaurusThe brain of Edmontosaurus has been described in several papers and abstracts through the use of endocasts of the cavity where the brain had been. E. annectens and E. regalis, as well as specimens not identified to species, have been studied in this way. The brain was not particularly large for an animal the size of Edmontosaurus. The space holding it was only about a quarter of the length of the skull, and various endocasts have been measured as displacing 374 milliliters (13 US fl oz)[76] to 450 milliliters (15 US fl oz), which does not take into account that the brain may have occupied as little as 50% of the space of the endocast, the rest of the space being taken up by the dura mater surrounding the brain. For example, the brain of the specimen with the 374 millilitre endocast is estimated to have had a volume of 268 milliliters (9 US fl oz). The brain was an elongate structure, and as with other non-mammals, there would have been no neocortex. Like Stegosaurus, the neural canal was expanded in the hips, but not to the same degree: the endosacral space of Stegosaurus had 20 times the volume of its endocranial cast, whereas the endosacral space of Edmontosaurus was only 2.59 times larger in volume.
A 1905 chart showing the relatively small brains of a Triceratops (top) and EdmontosaurusThe brain of Edmontosaurus has been described in several papers and abstracts through the use of endocasts of the cavity where the brain had been. E. annectens and E. regalis, as well as specimens not identified to species, have been studied in this way. The brain was not particularly large for an animal the size of Edmontosaurus. The space holding it was only about a quarter of the length of the skull, and various endocasts have been measured as displacing 374 milliliters (13 US fl oz)[76] to 450 milliliters (15 US fl oz), which does not take into account that the brain may have occupied as little as 50% of the space of the endocast, the rest of the space being taken up by the dura mater surrounding the brain. For example, the brain of the specimen with the 374 millilitre endocast is estimated to have had a volume of 268 milliliters (9 US fl oz). The brain was an elongate structure, and as with other non-mammals, there would have been no neocortex. Like Stegosaurus, the neural canal was expanded in the hips, but not to the same degree: the endosacral space of Stegosaurus had 20 times the volume of its endocranial cast, whereas the endosacral space of Edmontosaurus was only 2.59 times larger in volume.
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Feeding adaptations
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As a hadrosaurid, Edmontosaurus was a large terrestrial herbivore. Its teeth were continually replaced and packed into dental batteries that contained hundreds of teeth, only a relative handful of which were in use at any time. It used its broad beak to cut loose food, perhaps by cropping, or by closing the jaws in a clamshell-like manner over twigs and branches and then stripping off the more nutritious leaves and shoots. Because the tooth rows are deeply indented from the outside of the jaws, and because of other anatomical details, it is inferred that Edmontosaurus and most other ornithischians had cheek-like structures, muscular or non-muscular. The function of the cheeks was to retain food in the mouth. The animal’s feeding range would have been from ground level to around 4 meters (13 ft) above.Before the 1960s and 1970s, the prevailing interpretation of hadrosaurids like Edmontosaurus was that they were aquatic and fed on aquatic plants. An example of this is William Morris’s 1970 interpretation of an edmontosaur skull with nonbony beak remnants. He proposed that the animal had a diet much like that of some modern ducks, filtering plants and aquatic invertebrates like mollusks and crustaceans from the water and discharging water via V-shaped furrows along the inner face of the upper beak. This interpretation of the beak has been rejected, as the furrows and ridges are more like those of herbivorous turtle beaks than the flexible structures seen in filter-feeding birds.The prevailing model of how hadrosaurids fed was put forward in 1984 by David B. Weishampel. He proposed that the structure of the skull permitted motion between bones that led to backward and forward motion of the lower jaw, and outward bowing of the tooth-bearing bones of the upper jaw when the mouth was closed. The teeth of the upper jaw would grind against the teeth of the lower jaw like rasps, processing plant material trapped between them. Such a motion would parallel the effects of mastication in mammals, although accomplishing the effects in a completely different way. An important piece of evidence for Weishampel’s model is the orientation of scratches on the teeth, showing the direction of jaw action. Other movements could produce similar scratches, though, such as movement of the bones of the two halves of the lower jaw. Not all models have been scrutinized under present techniques.Weishampel developed his model with the aid of a computer simulation. Natalia Rybczynski and colleagues have updated this work with a much more sophisticated three-dimensional animation model, scanning a skull of E. regalis with lasers. They were able to replicate the proposed motion with their model, although they found that additional secondary movements between other bones were required, with maximum separations of 1.3 to 1.4 centimeters (0.51 to 0.55 in) between some bones during the chewing cycle. Rybczynski and colleagues were not convinced that the Weishampel model is viable, but noted that they have several improvements to implement to their animation. Planned improvements include incorporating soft tissue and tooth wear marks and scratches, which should better constrain movements. They note that there are several other hypotheses to test as well. Further work by Casey Holliday and Lawrence Witmer found that ornithopods like Edmontosaurus lacked the types of skull joints seen in those modern animals that are known to have kinetic skulls (skulls that permit motion between their constituent bones), such as squamates and birds. They proposed that joints that had been interpreted as permitting movement in dinosaur skulls were actually cartilaginous growth zones
As a hadrosaurid, Edmontosaurus was a large terrestrial herbivore. Its teeth were continually replaced and packed into dental batteries that contained hundreds of teeth, only a relative handful of which were in use at any time. It used its broad beak to cut loose food, perhaps by cropping, or by closing the jaws in a clamshell-like manner over twigs and branches and then stripping off the more nutritious leaves and shoots. Because the tooth rows are deeply indented from the outside of the jaws, and because of other anatomical details, it is inferred that Edmontosaurus and most other ornithischians had cheek-like structures, muscular or non-muscular. The function of the cheeks was to retain food in the mouth. The animal’s feeding range would have been from ground level to around 4 meters (13 ft) above.Before the 1960s and 1970s, the prevailing interpretation of hadrosaurids like Edmontosaurus was that they were aquatic and fed on aquatic plants. An example of this is William Morris’s 1970 interpretation of an edmontosaur skull with nonbony beak remnants. He proposed that the animal had a diet much like that of some modern ducks, filtering plants and aquatic invertebrates like mollusks and crustaceans from the water and discharging water via V-shaped furrows along the inner face of the upper beak. This interpretation of the beak has been rejected, as the furrows and ridges are more like those of herbivorous turtle beaks than the flexible structures seen in filter-feeding birds.The prevailing model of how hadrosaurids fed was put forward in 1984 by David B. Weishampel. He proposed that the structure of the skull permitted motion between bones that led to backward and forward motion of the lower jaw, and outward bowing of the tooth-bearing bones of the upper jaw when the mouth was closed. The teeth of the upper jaw would grind against the teeth of the lower jaw like rasps, processing plant material trapped between them. Such a motion would parallel the effects of mastication in mammals, although accomplishing the effects in a completely different way. An important piece of evidence for Weishampel’s model is the orientation of scratches on the teeth, showing the direction of jaw action. Other movements could produce similar scratches, though, such as movement of the bones of the two halves of the lower jaw. Not all models have been scrutinized under present techniques.Weishampel developed his model with the aid of a computer simulation. Natalia Rybczynski and colleagues have updated this work with a much more sophisticated three-dimensional animation model, scanning a skull of E. regalis with lasers. They were able to replicate the proposed motion with their model, although they found that additional secondary movements between other bones were required, with maximum separations of 1.3 to 1.4 centimeters (0.51 to 0.55 in) between some bones during the chewing cycle. Rybczynski and colleagues were not convinced that the Weishampel model is viable, but noted that they have several improvements to implement to their animation. Planned improvements include incorporating soft tissue and tooth wear marks and scratches, which should better constrain movements. They note that there are several other hypotheses to test as well. Further work by Casey Holliday and Lawrence Witmer found that ornithopods like Edmontosaurus lacked the types of skull joints seen in those modern animals that are known to have kinetic skulls (skulls that permit motion between their constituent bones), such as squamates and birds. They proposed that joints that had been interpreted as permitting movement in dinosaur skulls were actually cartilaginous growth zones
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.The immobile skull model was challenged in 2009 by Vincent Williams and colleagues. Returning to tooth microwear, they found four classes of scratches on Edmontosaurus teeth. The most common class was interpreted as resulting from an oblique motion, not a simple up-down or front-back motion, which is more consistent with the Weishampel model. This motion is thought to have been the primary motion for grinding food. Two scratch classes were interpreted as resulting from forward or backward movement of the jaws. The other class was variable and probably resulted from opening the jaws. The combination of movements is more complex than had been previously predicted. Because scratches dominate the microwear texture, Williams et al. suggested Edmontosaurus was a grazer instead of a browser, which would be predicted to have fewer scratches due to eating less abrasive materials.
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Candidates for ingested abrasives include silica-rich plants like horsetails and soil that was accidentally ingested due to feeding at ground level.Reports of gastroliths, or stomach stones, in the hadrosaurid Claosaurus are actually based on a probable double misidentification. First, the specimen is actually of Edmontosaurus annectens. Barnum Brown, who discovered the specimen in 1900, referred to it as Claosaurus because E. annectens was thought to be a species of Claosaurus at the time. Additionally, it is more likely that the supposed gastroliths represent gravel washed in during burial.
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Gut contents
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Both of the “mummy” specimens collected by the Sternbergs were reported to have had possible gut contents. Charles H. Sternberg reported the presence of carbonized gut contents in the American Museum of Natural History specimen, but this material has not been described. The plant remains in the Senckenberg Museum specimen have been described, but have proven difficult to interpret. The plants found in the carcass included needles of the conifer Cunninghamites elegans, twigs from conifer and broadleaf trees, and numerous small seeds or fruits. Upon their description in 1922, they were the subject of a debate in the German-language journal Paläontologische Zeitschrift. Kräusel, who described the material, interpreted it as the gut contents of the animal, while Abel could not rule out that the plants had been washed into the carcass after death.At the time, hadrosaurids were thought to have been aquatic animals, and Kräusel made a point of stating that the specimen did not rule out hadrosaurids eating water plants. The discovery of possible gut contents made little impact in English-speaking circles, except for another brief mention of the aquatic-terrestrial dichotomy, until it was brought up by John Ostrom in the course of an article reassessing the old interpretation of hadrosaurids as water-bound. Instead of trying to adapt the discovery to the aquatic model, he used it as a line of evidence that hadrosaurids were terrestrial herbivores. While his interpretation of hadrosaurids as terrestrial animals has been generally accepted, the Senckenberg plant fossils remain equivocal. Kenneth Carpenter has suggested that they may actually represent the gut contents of a starving animal, instead of a typical diet. Other authors have noted that because the plant fossils were removed from their original context in the specimen and were heavily prepared, it is no longer possible to follow up on the original work, leaving open the possibility that the plants were washed-in debris.
Both of the “mummy” specimens collected by the Sternbergs were reported to have had possible gut contents. Charles H. Sternberg reported the presence of carbonized gut contents in the American Museum of Natural History specimen, but this material has not been described. The plant remains in the Senckenberg Museum specimen have been described, but have proven difficult to interpret. The plants found in the carcass included needles of the conifer Cunninghamites elegans, twigs from conifer and broadleaf trees, and numerous small seeds or fruits. Upon their description in 1922, they were the subject of a debate in the German-language journal Paläontologische Zeitschrift. Kräusel, who described the material, interpreted it as the gut contents of the animal, while Abel could not rule out that the plants had been washed into the carcass after death.At the time, hadrosaurids were thought to have been aquatic animals, and Kräusel made a point of stating that the specimen did not rule out hadrosaurids eating water plants. The discovery of possible gut contents made little impact in English-speaking circles, except for another brief mention of the aquatic-terrestrial dichotomy, until it was brought up by John Ostrom in the course of an article reassessing the old interpretation of hadrosaurids as water-bound. Instead of trying to adapt the discovery to the aquatic model, he used it as a line of evidence that hadrosaurids were terrestrial herbivores. While his interpretation of hadrosaurids as terrestrial animals has been generally accepted, the Senckenberg plant fossils remain equivocal. Kenneth Carpenter has suggested that they may actually represent the gut contents of a starving animal, instead of a typical diet. Other authors have noted that because the plant fossils were removed from their original context in the specimen and were heavily prepared, it is no longer possible to follow up on the original work, leaving open the possibility that the plants were washed-in debris.
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Interactions with theropods°
°The time span and geographic range of Edmontosaurus overlapped with Tyrannosaurus, and an adult specimen of E. annectens on display in the Denver Museum of Nature and Science shows evidence of a theropod bite in the tail. Counting back from the hip, the thirteenth to seventeenth vertebrae have damaged spines consistent with an attack from the right rear of the animal. One spine has a portion sheared away, and the others are kinked; three have apparent tooth puncture marks. The top of the tail was at least 2.9 meters (9.5 ft) high, and the only theropod species known from the same rock formation that was tall enough to make such an attack is T. rex. The bones are partially healed, but the edmontosaur died before the traces of damage were completely obliterated. The damage also shows signs of bone infection. Kenneth Carpenter, who studied the specimen, noted that there also seems to be a healed fracture in the left hip which predated the attack because it was more fully healed. He suggested that the edmontosaur was a target because it may have been limping from this earlier injury. Because it survived the attack, Carpenter suggested that it may have outmaneuvered or outran its attacker, or that the damage to its tail was incurred by the hadrosaurid using it as a weapon against the tyrannosaur.
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C) 1997 M.ShiraishiEdmontosaurus ) meaning ‘Edmonton lizard’ (after where it was found, in Edmonton, Alberta, Canada and Greek sauros meaning lizard) was a hadrosaurid dinosaur genus from the Maastrichtian, the last stage of the Cretaceous Period, 71-65 million years ago. A fully-grown adult could have been up to 9 metres (30 feet) long and some of the larger species reached 13 metres (43 feet). Its weight was in the region of 3.5 tonnes, making it one of the largest hadrosaurids.Edmontosaurus was erected by Lawrence Morris Lambe in 1917 from a find in the Edmonton Rock Formation, Alberta, using E. regalis as type species. Marsh named Claosaurus annectens in 1892, but this has now been reclassified as E. annectens. Likewise, Charles Mortram Sternberg named Thespesius in 1926, but this is also a species of Edmontosaurus, namely E. saskatchewanensis.The well-known hadrosaurid genus Anatosaurus has been synonymized with Edmontosaurus. Anatosaurus, meaning “duck lizard”, because of its wide, duck-like bill (Latin anato = duck + Greek sauros = lizard). The type species of Anatosaurus, A. annectens, was re-named Edmontosaurus annectens, forcing the name Anatosaurus to be abandoned as a junior synonym. Similarly, Anatosaurus saskatchewanensis was sunk into Edmontosaurus as E. saskatchewanensis. Two other species of Anatosaurus, A. longiceps (originally Trachodon) and A. copei (the famous mount at the American Museum of Natural History), were found to differ from Edmontosaurus were placed in a separate genus, Anatotitan.Edmontosaurus could pass the toughest food back and forth across the teeth with its muscular cheek pouches. To fit so many teeth into its mouth, they were packed into tight “banks” of up to sixty rows, and new teeth constantly grew to replace lost teeth — analogous to a modern shark. The bones of the upper jaw would flex outwards as lower jaw came up, so the mandible could grind against it. Typical food would have included conifer needles, seeds and twigs, and these have been found in the body cavities of fossilized edmontosaurs. It was evidently a tree-browser.The 1908 discovery in Wyoming was especially remarkable in that paleontologists actually recovered fossilized imprints of Edmontosaurus’ skin. The impression must have been left by the skin drying very quickly and fixing its shape into the mud. It is from these impressions that we know the skin was scaly and leathery, and the thigh muscle was under the skin of the body. This would have given the impression that the leg left its body at the knee, and the whole thigh was under the skin. This only contributes to its resemblance to a duck. It also had a number of tubercles (bumps) along its neck and down its back and tail.Edmontosaurus was bipedal but could certainly have walked on four legs. The forelimbs are shorter than the hinds but not sufficiently that four-legged motivation was unfeasible. The front feet also had hooves on two fingers, and weight-bearing pads like those of Camarasaurus. The rear feet had three funtional toes and all were hoofed. The bone structure in the lower limbs suggests that both the legs and feet were attached to very powerful muscles. The spine curved downwards at the shoulders, so Edmontosaurus would have had a low posture and would have browsed close to the ground. Despite the power of the limbs, Edmontosaurus would only have been slow-moving and had few defensive features. To survive, it must have had keen eyesight, hearing and smell to get early warning of predators. © 2007 Answers Corporation
Edmontosaurus
Edmontosaurus was a Herbivore from the Late Cretaceous Period.
Edmontosaurus
Edmontosaurus meaning ‘Edmonton lizard’ (after where it was found, in Edmonton, Alberta, Canada and Greek sauros meaning lizard) was a hadrosaurid dinosaur genus from the Maastrichtian, the last stage of the Cretaceous Period, 71-65 million years ago. A fully-grown adult could have been up to 9 metres (30 feet) long and some of the larger species reached 13 metres (43 feet). Its weight was in the region of 3.5 tonnes, making it one of the largest hadrosaurids.
Edmontosaurus was een hadrosauriër of eendesnaveldinosauriër behorend tot de groep van de Edmontosaurini. Het was een herbivoor zonder klauwen. Wel kon hij wellicht door een op te zwellen neuszak zijn soortgenoten waarschuwen voor gevaar. Hij was familie vanAnatotitan en leefde tijdens het late Krijt in het huidige Noord-Amerika.
De eerste soort, E. regalis werd in 1917 beschreven door Lawrence Morris Lambe. De geslachtsnaam verwijst naar de stad Edmonton in Canada; de soortaanduiding betekent: “koninklijk” en verwijst naar de enorme omvang van het dier dat een lengte kon bereiken van zo’n dertien meter. Er wordt een tweede soort onderscheiden: E. annectens, in 1892 door Othniel Charles Marsh beschreven als Claosaurus annectus. De derde soort is E. saskatchewanensis. Beide laatste zijn een tijdje ondergebracht bij Anatosaurus.
Een skelet van Edmontosaurus is te zien in Naturalis
Sommige dinosaurussen zijn zo groot dat ze niet op één verdieping van een gebouw zouden passen, zoals deze Camarasaurus in het museum Naturalis in Leiden
Rechts staat het skelet van edmontosaurus opgesteld
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- Efraasia Efraasia is een uitgestorven monotypisch geslacht van plantenetende basale sauropodomorfe dinosauriërs. De enige soort, Efraasia minor, leefde ongeveer 210 miljoen jaar geleden, tijdens het Opper-Trias, in het gebied van het huidige Duitsland.
Efraasia
http://www.dinosoria.com/prosauropodes.htm
Skull reconstruction of Efraasia minor (based on SMNS 12216, 12684, 12667). From Yates, 2003. Scale bar is 5 cm.
http://www.palaeocritti.com/by-group/dinosauria/sauropoda/efraasia
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- Einiosaurus—> Einiosaurus is een uitgestorven geslacht van plantenetende ornithischische dinosauriërs, behorend tot de groep van de Ceratopia, dat tijdens het Laat-Krijt leefde in het gebied van het huidige Noord-Amerika
Einiosaurus had a large downward-curving nasal horn.
MfN Berlin Elaphrosaurus mount
http://dinosaurpalaeo.wordpress.com/2012/10/04/theropod-thursday-29-elaphrosaurus/
- Elmisaurus
- Elopteryx
- Elosaurus – junior synonym of Apatosaurus
- Elrhazosaurus
- “Elvisaurus” – nomen nudum; Cryolophosaurus
- Emausaurus
- Embasaurus
- Empaterias – misspelling of Epanterias
- Enigmosaurus
- Eobrontosaurus
- Eocarcharia
- Eoceratops – junior synonym of Chasmosaurus
- Eocursor
- Eodromaeus
- “Eohadrosaurus” – nomen nudum; Eolambia
- Eolambia
- Eolosaurus[4] – junior synonym of Aeolosaurus
- Eomamenchisaurus
theropods <—documentatiemap & beeldmateriaal
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E.Tyrannus lengi Eotyrannus (“dawn tyrant”) was a tyrannosauroid theropod dinosaur hailing from the Early Cretaceous Wessex Formation beds, included in Wealden Group, located in the southwest coast of the Isle of Wight, United Kingdom. The remains, consisting of assorted skull, axial skeleton and apendicular skeleton elements, from a juvenile or subadult, found in a plant debris clay bed, was described by Hutt et al. in early 2001. The etymology of the generic name refers to the animal’s character as an “early tyrant”, while the specific epithet is a mention to the discoverer of the fossil. Eotyrannus is a 6 meter-long theropod whose tyrannosauroid character is given by serrated premaxillary teeth with a D cross section, proportionally elongate tibiae and metatarsals. Primitive characters for Tyrannosauroidea are the elongate neck vertebrae and the long well developed arms forelimbs along with the undecorated dorsal surface of the skull, unlike the more advanced tyrannosaurids. However this animal, proportionally, has one of the longest hands in Theropoda known to date.This theropod would be a probable predator of such herbivorous dinosaur species as Hypsilophodon and Iguanodon. E. lengi’s find corroborates the notion that early tyrannosaurs were gracile with long forelimbs and three-fingered grasping hands though the big size of the animal either means that early evolution for this clade was carried out at a big size or Eotyrannus developed big size independently. The find of this animal in Europe puts interesting questions to the purported Asian origin for these animals along with North American Stokesosaurus and European Aviatyrannis arguing for a more complex biogeography for tyrannosaurs.Order: Saurischia
Suborder: Theropoda
Superfamily: Tyrannosauroidea
Genus: Eotyrannus
Suborder: Theropoda
Superfamily: Tyrannosauroidea
Genus: Eotyrannus
- Epachthosaurus
- Epanterias – may be Allosaurus
- “Ephoenosaurus” – nomen nudum; Machimosaurus (a crocodilian)
- Epicampodon – actually a proterosuchid archosauriform
- Epichirostenotes
(Greek for “lizard in the tree”); Woodlands of Asia
Late Jurassic (150 million years ago)
About 6 inches long and one pound Probably omnivorous
Tiny size; long arms with clawed handsArchaeopteryx gets all the press, but there’s a convincing case to be made that Epidendrosaurus was the first reptile to be closer to a bird than to a dinosaur. This pint-sized theropod was less than half the size of its more famous cousin, and it’s a sure bet that it was covered with feathers. Most notably, Epidendrosaurus appears to have been adapted to an arboreal (tree-dwelling) lifestyle–its small size would have made it a simple matter to hop from branch to branch, and its long, curved claws were likely used to pry insects from tree bark.
So was Epidendrosaurus really a bird rather than a dinosaur?
As with all of the feathered “dino-birds,” as these reptiles are called, it’s impossible to say.
It’s better to think of the categories of “bird” and “dinosaur” as lying along a continuum, with some genera closer to either extreme and some smack in the middle.
- Erectopus —>Erectopus is een geslacht van vleesetende theropode dinosauriërs, behorend tot de Tetanurae, dat tijdens het vroege Krijt leefde in het gebied van het huidige Frankrijk. De enige benoemde soort is Erectopus superbus.
- Erlicosaurus – misspelling of Erlikosaurus
- Erlikosaurus
Fossil skull of the Cretaceous therizinosaur Erlikosaurus andrewsi (Credit: Image by Emily Rayfield, University of Bristol)
http://www.sciencedaily.com/releases/2012/12/121219174154.htm
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0052289
- Eshanosaurus
- “Euacanthus” – nomen nudum; junior synonym of Polacanthus
- (Ichnofossil )Eubrontes (?) Glenrosensies ,
track with partly mud-collapsed digits
Track name: Eubrontes glenrosensis sp.
Somervell County, Texas
Glen Rose Limestone
Lower Cretaceous (110 million years)
Eubrontes (?) glenrosensis SHULER, published by Adams et al. in Palaeontologia Electronica in 2010.
(The “toes” in the figure above) =
_The figure above is both an indirect vindication of Weems’ work, and a warning: many dinosauriformian and dinosaurian lineages are so convergent that they make highly similar tracks across vast distances in space and time!
Weems in 2003, in a very detailed study of the pedal morphology and posture of Plateosaurus, noted the excellent correlation between Plateosaurus and the Connecticut Eubrontes tracks
Weems, R.E. 2003. Plateosaurus foot structure suggests a single trackmaker for Eubrontes and Gigandipus footprints, p. 293–313.
Eubrontes
E. Hitchcock 1845, p. 23.
Type species: Eubrontes giganteus E. Hitchcock 1845, p. 23.
Lithographs and photographs of Eubrontes giganteus and referred specimens (from Olsen et al., 1998):(Scale, 5 cm, in the lithographs added by authors)
A, lithograph of AC 15/3, Hitchcock (1836, Fig. 21)B, lithograph of AC 15/3, Buckland (1836, Pl. 26b, Fig. 1)
C, lithograph of AC 15/3, Hitchcock (1848, Pl. 1, Fig. 1)
D, lithograph of AC 15/3, Hitchcock (1858, Pl. 57, fig 1)
- Eucamerotus
- Eucentrosaurus – junior synonym (unneeded replacement name) of Centrosaurus
- Eucercosaurus – possibly Anoplosaurus
- Eucnemesaurus
- Eucoelophysis – actually a non-dinosaurian dinosauromorph
- “Eugongbusaurus” – nomen nudum
http://en.wikipedia.org/wiki/File:Euoplocephalus-tutus-1.jpg //Euoplocephalus-Skeleton in im Senckenberg Museum, Frankfurt//
Life restoration of Euoplocephalus.
- Euoplocephalus Euoplocephalus Thyreophora/Ankylosauridae
Built like an armored tank, Euoplocephalus ambled through the late Cretaceous landscape, well equipped to withstand attack from any other dinosaur. Low slung and broad, the back of Euoplocephalus bore rows of bony shields with some taller spikes over the shoulders and at the base of the tail. There were also spikes on the dinosaur’s cheeks and behind each eye, protecting the head.
The most lethal weapon in Euoplocephalus’s armory was the double-headed club at the end of the long, stiffened tail. The base of the tail was quite flexible, but the last third was welded into a stiff rod by long struts growing out of each vertebra. The tail club could be swung most effectively from side to side, swiping at the feet of an attacking predator. If it connected with full force, it could shatter the ankle bones of the attacker, a wound that could later prove fatal.
Euoplocephalus had a compact, rounded head. Like other ankylosaurids, but unlike nodosaurids, it had a complex and convoluted nasal passage in the skull, but the function that this served is not clear. Perhaps the extra length given by the twists and loops allowed air to be warmed while the animal was breathing in, or perhaps this passage collected moisture from air being exhaled. The passage may also have been lined with sensors that gave Euoplocephalus an enhanced sense of smell for detecting food, predators, or potential mates.
The mouth had a broad beak at the front and a wide palate lined with small teeth. This arrangement suggests that Euoplocephalus was not particularly selective about what it ate and would consume almost any plant material that it could reach.
Around 40 specimens of Euoplocephalus have been found. All were isolated finds, which suggests thst these animals were loners rather than pack or herd animals. Packs and herds provided plant-eaters with a defense against predators but, perhaps because it was so heavily armored, Euoplocephalus had no need to rely on group behavior for protection.
Euoplocephalus is medium- to large-sized ankylosaurid dinosar and is common from the Upper Cretaceous sediments of North America. It has slit-like nostrils, divided by a vertical septum. As in other ankylosaurids, this dinosaur has small teeth, and tooth shape indicates a herbivorous diet.
Euoplocephalus stratigraphy Jan 30, ’13 by Tim /Consulting THE DINOSAURIA, I note that Euoplocephalus is known from the Upper Two Medicine formation as well as the Dinosaur Park. No doubt, that is why Euoplocephalus is thought to have outlasted Scolosaurus and Dyoplosaurus. The three genera may seem coeval in Dinosaur Park strata, but the Upper Two Medicine is younger than the Dinosaur Park. Available stratigraphic data suggests Scolosaurus and Dyoplosaurus disappeared about 75 MYA, but Euoplocephalus lasted until 72-71 MYA, or roughly the end of the Campanian. Euoplocephalus may have been eliminated by the Bearpaw transgression, inasmuch as ankylosaurids preferred interior as opposed to near-marine habitat. Of course, North American ankylosaurids weren’t eliminated entirely c 71 MYA, since the early Maastrichtian taxon and Ankylosaurus lived in the same region later. They or their ancestors may have inhabited areas less affected by the transgression.
- Eupodosaurus – a nothosaur synonymous with Lariosaurus
- “Eureodon” – nomen nudum; Tenontosaurus
- Eurolimnornis – possibly a bird
- Euronychodon
- Europasaurus
- Euskelosaurus
- Eustreptospondylus
http://en.wikipedia.org/wiki/List_of_dinosaurs
Tsjok's blog 
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March 6, 2009
” a trackmaker assignment is a hypothesis.
Eubrontes isn’t a dinosaur body-fossil genus. It’s an ichnotaxon–in this case a footprint genus. There are no Eubrontes skeletons out there. The name is restricted to the footprint morphotype alone. Ignoring the issues with slapping Latin bionomials on sedimentary structures, this is a common practice and Eubrontes fossils represent a fairly characteristic type of footprint shape found across North America in Lower Jurassic rocks.
The question of what animal made Eubrontes is a different issue, but identifying a footprint as a Eubrontes track is a matter of studying the footprint itself and comparing it to other footprints. There need not be dinosaur skeletal feet preserved nearby that fit the tracks. Again, the issue of who made the fooprint is a different issue from figuring out whether or not the track morphology is consistent with the morphotype that is known as Eubrontes. ”
http://scienceblogs.com/pharyngula/2009/03/06/how-did-dinosaurs-sit-down/