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96-1171: Edmontonia is a genus of panoplosaurin nodosaurid dinosaur from the Late Cretaceous Period . It is part of the Nodosauridae , a family within Ankylosauria . It is named after the Edmonton Formation (now the Horseshoe Canyon Formation in Canada), the unit of rock where it was found. Edmontonia was bulky, broad and tank -like. Its length has been estimated at 6.6 m (22 ft). In 2010, Gregory S. Paul considered both main Edmontonia species, E. longiceps and E. rugosidens , to be equally long at six metres and weigh three tonnes. Edmontonia had small, oval ridged bony plates on its back and head and many sharp spikes along its sides. The four largest spikes jutted out from

192-628: A hernia . Spinal stenosis is a narrowing of the spinal canal which can occur in any region of the spine though less commonly in the thoracic region. The stenosis can constrict the spinal canal giving rise to a neurological deficit . Pain at the coccyx (tailbone) is known as coccydynia . Spinal cord injury is damage to the spinal cord that causes changes in its function, either temporary or permanent. Spinal cord injuries can be divided into categories: complete transection, hemisection, central spinal cord lesions, posterior spinal cord lesions, and anterior spinal cord lesions. Scalloping vertebrae

288-421: A "sacral rod" of four fused rear dorsal vertebrae, three sacral vertebrae, two caudosacrals and at least twenty, but probably about forty, tail vertebrae. In the neck the first two vertebrae, the atlas and axis, are fused. In the shoulder girdle, the coracoid has a rectangular profile, in contrast to the more rounded shape with Panoplosaurus . Two sternal plates are present, connected to sternal ribs. The forelimb

384-412: A central cavity, the central canal . Adjacent to each vertebra emerge spinal nerves . The spinal nerves provide sympathetic nervous supply to the body, with nerves emerging forming the sympathetic trunk and the splanchnic nerves . The spinal canal follows the different curves of the column; it is large and triangular in those parts of the column that enjoy the greatest freedom of movement, such as

480-449: A curve, convex forward, that begins at the axis (second cervical vertebra) at the apex of the odontoid process or dens and ends at the middle of the second thoracic vertebra; it is the least marked of all the curves. This inward curve is known as a lordotic curve. The thoracic curve, concave forward, begins at the middle of the second and ends at the middle of the twelfth thoracic vertebra. Its most prominent point behind corresponds to

576-556: A definition followed by Vickaryous, Teresa Maryańska , and Weishampel in 2004. Vickaryous et al. considered two genera of nodosaurids to be of uncertain placement ( incertae sedis ): Struthiosaurus and Animantarx , and considered the most primitive member of the Nodosauridae to be Cedarpelta . Following the publication of the PhyloCode , Nodosauridae needed to be formally defined following certain parameters, including that

672-632: A derived nodosaurid, closely related to Panoplosaurus . Russell in 1940 named a separate Edmontoniinae . In 1988 Bakker proposed that the Edmontoniinae with the Panoplosaurinae should be joined into Edmontoniidae , the presumed sister group of the Nodosauridae within Nodosauroidea which he assumed not be ankylosaurians but the last surviving stegosaurians. Exact cladistic analysis has not confirmed these hypotheses however, and

768-513: A metre long, is somewhat elongated with a protruding truncated snout. The snout carried a horny upper beak and the front snout bones, the premaxillae , were toothless. The cutting edge of the upper beak continued into the maxillary tooth rows, each containing fourteen to seventeen small teeth. In each dentary of the lower jaws, eighteen to twenty-one teeth were present. In the sides of the snout large depressions were present, "nasal vestibules", that each possessed two smaller openings. The top of these

864-413: A neural arch, while the haemal arch is found underneath the centrum in the caudal (tail) vertebrae of fish , most reptiles , some birds, some dinosaurs and some mammals with long tails. The vertebral processes can either give the structure rigidity, help them articulate with ribs, or serve as muscle attachment points. Common types are transverse process, diapophyses, parapophyses, and zygapophyses (both

960-465: A nodosaurid; such structures had already been well established in ankylosaurids. The air tracts are however, much simpler than in the typical ankylosaurid condition, and are not convoluted while lacking bony turbinate bones . The nasal cavity is separated into two halves along the midline by a bone wall. This septum is continued to below by the vomers , which are keeled, the keel featuring a pendulum-shaped appendage. Another similarity with Ankylosauridae

1056-411: A predator. Rings in the petrified wood of trees contemporary with Edmontonia show evidence of strong seasonal changes in precipitation and temperature; this may hold an explanation for why so many specimens have been found with their armor plating and spikes in the same position they were in life. The Edmontonia could have died due to drought, dried up, and then rapidly became covered in sediment when

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1152-535: A region can vary but overall the number remains the same. In a human vertebral column, there are normally 33 vertebrae. The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs , and the lower nine are fused in adults, five in the sacrum and four in the coccyx , or tailbone . The articulating vertebrae are named according to their region of the spine. From top to bottom, there are 7 cervical vertebrae , 12 thoracic vertebrae and 5 lumbar vertebrae . The number of those in

1248-456: A region can vary but overall the number remains the same. The number of those in the cervical region, however, is only rarely changed. The vertebrae of the cervical, thoracic, and lumbar spines are independent bones and generally quite similar. The vertebrae of the sacrum and coccyx are usually fused and unable to move independently. Two special vertebrae are the atlas and axis , on which the head rests. A typical vertebra consists of two parts:

1344-399: A remnant of the notochord. Reptiles often retain the primitive intercentra, which are present as small crescent-shaped bony elements lying between the bodies of adjacent vertebrae; similar structures are often found in the caudal vertebrae of mammals. In the tail, these are attached to chevron-shaped bones called haemal arches , which attach below the base of the spine, and help to support

1440-438: A result of lifting the head and the lumbar curvature forms as a result of walking. The vertebral column surrounds the spinal cord which travels within the spinal canal , formed from a central hole within each vertebra . The spinal cord is part of the central nervous system that supplies nerves and receives information from the peripheral nervous system within the body. The spinal cord consists of grey and white matter and

1536-504: A vertebral column. The human spine is one of the most-studied examples, as the general structure of human vertebrae is fairly typical ( homologous ) of that found in other mammals , reptiles and birds . The shape of the vertebral body does, however, vary somewhat between different groups of living species. Individual vertebrae are named according to their corresponding body region ( neck , thorax , abdomen , pelvis or tail ). In clinical medicine , features on vertebrae (particularly

1632-591: Is a family of ankylosaurian dinosaurs known from the Late Jurassic to the Late Cretaceous periods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as a monophyletic clade as the sister taxon to the Ankylosauridae , some analyses recover it as a paraphyletic grade leading to the ankylosaurids. Nodosaurids, like their sister group

1728-413: Is classed as a spinal disease or dorsopathy and includes the following abnormal curvatures: Individual vertebrae of the human vertebral column can be felt and used as surface anatomy , with reference points are taken from the middle of the vertebral body. This provides anatomical landmarks that can be used to guide procedures such as a lumbar puncture and also as vertical reference points to describe

1824-546: Is closely related to Panoplosaurus . Edmontonia australis was named by Tracy Lee Ford in 2000 on the basis of cervical scutes, the holotype NMMNH P-25063, a pair of medial keeled neck osteoderms from the Maastrichtian Kirtland Formation of New Mexico and the paratype NMMNH P-27450, a right middle neck plate. Although later considered to a dubious name , it is now considered a junior synonym of Glyptodontopelta mimus. The naming history

1920-416: Is curved in several places, a result of human bipedal evolution . These curves increase the vertebral column's strength, flexibility, and ability to absorb shock, stabilising the body in upright position. When the load on the spine is increased, the curvatures increase in depth (become more curved) to accommodate the extra weight. They then spring back when the weight is removed. The upper cervical spine has

2016-624: Is defined in the PhyloCode as "the largest clade containing Panoplosaurus mirus , but not Nodosaurus textilis and Struthiosaurus austriacus " while Struthiosaurini has a similar definition of "the largest clade containing Struthiosaurus austriacus , but not Nodosaurus textilis and Panoplosaurus mirus ". Topology A below demonstrates these relationships, following the phylogenetic analyses of Rivera-Sylva and colleagues (2018), with clade names added by definition from Madzia et al. (2021). However, in 2023, Raven and colleagues proposed an alternate phylogeny for nodosaurids; instead of

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2112-436: Is distinguished from E. rugosidens in lacking sideways projecting osteoderms behind the eye sockets; having tooth rows that are less divergent; possessing a more narrow palate; having a sacrum that is wider than long and more robust; and in having shorter spikes at the sides. Also, an ossified cheek plate, known from E. rugosidens specimens, has not been found with Edmontonia longiceps . The skull of Edmontonia , up to half

2208-528: Is known from the Horseshoe Canyon Formation , from the middle unit, which was dated to 71.5-71 million years ago in 2009. The fauna of the Horseshoe Canyon Formation is well-known, as vertebrate fossils, including those of dinosaurs, are quite common. Sharks , rays , sturgeons , bowfins , gars and the gar-like Aspidorhynchus made up the fish fauna. The saltwater plesiosaur Leurospondylus has been found in marine sediments in

2304-406: Is robust but relatively long. In Edmontonia longiceps and E. rugosidens the deltopectoral crest of the humerus is gradually rounded. The metacarpus is robust compared to that of Panoplosaurus . The hand very likely was tetradactyl, having four fingers. The exact number of phalanges is unknown but the formula was by W.P. Coombs suggested to be 2-3-3-4-?. Apart from the head armour, the body

2400-432: Is shallow, and by the laminae and transverse processes in the thoracic region, where it is deep and broad; these grooves lodge the deep muscles of the back. Lateral to the spinous processes are the articular processes, and still more laterally the transverse processes. In the thoracic region, the transverse processes stand backward, on a plane considerably behind that of the same processes in the cervical and lumbar regions. In

2496-412: Is the increase in the concavity of the posterior vertebral body. It can be seen on lateral X-ray and sagittal views of CT and MRI scans. Its concavity is due to the increased pressure exerting on the vertebrae due to a mass. Internal spinal mass such as spinal astrocytoma , ependymoma , schwannoma , neurofibroma , and achondroplasia causes vertebrae scalloping. Excessive or abnormal spinal curvature

2592-403: Is the presence of a secondary bone palate, a possible case of parallel evolution . This has been shown too for Panoplosaurus . The head armour tiles, or caputegulae , are smooth. Details differ between the various specimens but all share a large central nasal tile on the snout, bend large "loreal" tiles at the rear snout edges and a large central caputegula on the skull roof. The tiles behind

2688-521: The Arabian (breed) can have one less vertebrae and pair of ribs. This anomaly disappears in foals that are the product of an Arabian and another breed of horse. Vertebrae are defined by their location in the vertebral column. Cervical vertebrae are those in the neck area. With the exception of the two sloth genera ( Choloepus and Bradypus ) and the manatee genus, ( Trichechus ), all mammals have seven cervical vertebrae. In other vertebrates,

2784-433: The intervertebral discs . The notochord disappears in the sclerotome (vertebral body) segments but persists in the region of the intervertebral discs as the nucleus pulposus . The nucleus pulposus and the fibers of the anulus fibrosus make up the intervertebral disc. The primary curves (thoracic and sacral curvatures) form during fetal development. The secondary curves develop after birth. The cervical curvature forms as

2880-412: The paraxial mesoderm that lies at the sides of the neural tube and they contain the precursors of spinal bone, the vertebrae ribs and some of the skull, as well as muscle, ligaments and skin. Somitogenesis and the subsequent distribution of somites is controlled by a clock and wavefront model acting in cells of the paraxial mesoderm. Soon after their formation, sclerotomes , which give rise to some of

2976-436: The sacrum and coccyx are fused without a central foramen. The vertebral arch is formed by a ventral pair of pedicles and a dorsal pair of laminae , and supports seven processes , four articular , two transverse and one spinous , the latter also being known as the neural spine. The transverse and spinous processes and their associated ligaments serve as important attachment sites for back and paraspinal muscles and

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3072-435: The spinal canal , a body cavity that contains the spinal cord . Because the vertebral column will outgrow the spinal cord during child development , by adulthood the spinal cord often ends at the upper lumbar spine (at around L1/L2 level), the lower ( caudal ) end of the spinal canal is occupied by a ponytail -like bundle of spinal nerves descriptively called cauda equina (from Latin " horse's tail " ), and

3168-411: The spinal cord and the notochord . This column of tissue has a segmented appearance, with alternating areas of dense and less dense areas. As the sclerotome develops, it condenses further eventually developing into the vertebral body . Development of the appropriate shapes of the vertebral bodies is regulated by HOX genes . The less dense tissue that separates the sclerotome segments develop into

3264-420: The spinous process ) can be used as surface landmarks to guide medical procedures such as lumbar punctures and spinal anesthesia . There are also many different spinal diseases in humans that can affect both the bony vertebrae and the intervertebral discs, with kyphosis / scoliosis , ankylosing spondylitis , degenerative discs and spina bifida being recognizable examples. The number of vertebrae in

3360-438: The thoracolumbar fasciae . The spinous processes of the cervical and lumbar regions can be felt through the skin, and are important surface landmarks in clinical medicine . The four articular processes for two pairs of plane facet joints above and below each vertebra, articulating with those of the adjacent vertebrae and are joined by a thin portion of the neural arch called the pars interarticularis . The orientation of

3456-409: The vertebral body (or centrum ), which is ventral (or anterior , in the standard anatomical position ) and withstands axial structural load ; and the vertebral arch (also known as neural arch ), which is dorsal (or posterior ) and provides articulations and anchorages for ribs and core skeletal muscles . Together, these enclose the vertebral foramen , the series of which align to form

3552-586: The Edmonton Formation. The specific name longiceps means "long-headed" in Latin. Its holotype is specimen NMC 8531 , consisting of a skull, right lower jaw and much of the postcranial skeleton, including the armour. It was discovered near Morrin in 1924 by George Paterson, the teamster of the expedition led by C.M. Sternberg. Edmontonia species include: Edmontonia schlessmani was a renaming in 1992 of Denversaurus schlessmani ("Schlessman's Denver lizard ") by Adrian Hunt and Spencer Lucas . This taxon

3648-499: The Horseshoe Canyon, while freshwater environments were populated by turtles , Champsosaurus , and crocodilians like Leidyosuchus and Stangerochampsa . Dinosaurs dominate the fauna, especially hadrosaurs, which make up half of all dinosaurs known, including the genera Edmontosaurus , Saurolophus and Hypacrosaurus . Ceratopsians and ornithomimids were also very common, together making up another third of

3744-721: The addition of another internal specifier was deemed unnecessary. Nodosauridae is traditionally composed of the basal clade Polacanthinae (sometimes recovered outside of the Nodosauridae), as well as the Panoplosaurini and Struthiosaurini within the Nodosaurinae . Nodosaurinae is defined in the PhyloCode as "the largest clade containing Nodosaurus textilis , but not Hylaeosaurus armatus , Mymoorapelta maysi , and Polacanthus foxii ". Panoplosaurini

3840-425: The adjacent vertebra to a degree less than a dislocation. Spondylolysis , also known as a pars defect, is a defect or fracture at the pars interarticularis of the vertebral arch. Spinal disc herniation , more commonly called a "slipped disc", is the result of a tear in the outer ring ( anulus fibrosus ) of the intervertebral disc , which lets some of the soft gel-like material, the nucleus pulposus , bulge out in

3936-541: The ankylosaurids, were heavily armored dinosaurs adorned with rows of bony armor nodules and spines ( osteoderms ), which were covered in keratin sheaths. Nodosaurids, like other ankylosaurians, were small- to large-sized, heavily built, quadrupedal , herbivorous dinosaurs , possessing small, leaf-shaped teeth. Unlike ankylosaurids, nodosaurids lacked mace-like tail clubs, instead having more flexible tail tips. Many nodosaurids had spikes projecting outward from their shoulders. One particularly well-preserved nodosaurid "mummy",

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4032-416: The bone of the skull, the vertebrae and ribs, migrate, leaving the remainder of the somite now termed a dermamyotome behind. This then splits to give the myotomes which will form the muscles and dermatomes which will form the skin of the back. Sclerotomes become subdivided into an anterior and a posterior compartment. This subdivision plays a key role in the definitive patterning of vertebrae that form when

4128-427: The bony vertebral body. In most ray-finned fishes , including all teleosts , these two structures are fused with, and embedded within, a solid piece of bone superficially resembling the vertebral body of mammals. In living amphibians , there is simply a cylindrical piece of bone below the vertebral arch, with no trace of the separate elements present in the early tetrapods. In cartilaginous fish , such as sharks ,

4224-577: The burial of the carcass. However, Carpenter and G.S. Paul, trying to reposition the spikes, found that it was impossible to rotate them without losing conformity with the remainder of the armour. The side spikes have solid, not hollow, bases. The spikes differ in size between E. rugosidens individuals; those of the E. longiceps holotype are relatively small. Behind the third halfring the back and hip are covered by numerous transverse rows of much smaller oval keeled osteoderms. These are not ordered in longitudinal rows. The front rows have plates oriented along

4320-506: The centrum. Centra with flat ends are acoelous , like those in mammals. These flat ends of the centra are especially good at supporting and distributing compressive forces. Amphicoelous vertebra have centra with both ends concave. This shape is common in fish, where most motion is limited. Amphicoelous centra often are integrated with a full notochord . Procoelous vertebrae are anteriorly concave and posteriorly convex. They are found in frogs and modern reptiles. Opisthocoelous vertebrae are

4416-423: The cervical and lumbar regions, and is small and rounded in the thoracic region, where motion is more limited. The spinal cord terminates in the conus medullaris and cauda equina . Spina bifida is a congenital disorder in which there is a defective closure of the vertebral arch. Sometimes the spinal meninges and also the spinal cord can protrude through this, and this is called spina bifida cystica . Where

4512-464: The cervical and upper part of the thoracic regions and gradually increasing in size to the last lumbar. They transmit the special spinal nerves and are situated between the transverse processes in the cervical region and in front of them, in the thoracic and lumbar regions. There are different ligaments involved in the holding together of the vertebrae in the column, and in the column's movement. The anterior and posterior longitudinal ligaments extend

4608-511: The cervical region, however, is only rarely changed, while that in the coccygeal region varies most. Excluding rare deviations, the total number of vertebrae ranges from 32 to 35. In about 10% of people, both the total number of pre-sacral vertebrae and the number of vertebrae in individual parts of the spine can vary. The most frequent deviations are: 11 (rarely 13) thoracic vertebrae, 4 or 6 lumbar vertebrae, 3 or 5 coccygeal vertebrae (rarely up to 7). There are numerous ligaments extending

4704-430: The cervical region, the transverse processes are placed in front of the articular processes, lateral to the pedicles and between the intervertebral foramina. In the thoracic region they are posterior to the pedicles, intervertebral foramina, and articular processes. In the lumbar region they are in front of the articular processes, but behind the intervertebral foramina. The sides of the vertebral column are separated from

4800-421: The child begins to walk. When viewed from in front, the width of the bodies of the vertebrae is seen to increase from the second cervical to the first thoracic; there is then a slight diminution in the next three vertebrae. Below this, there is again a gradual and progressive increase in width as low as the sacrovertebral angle. From this point there is a rapid diminution, to the apex of the coccyx. From behind,

4896-820: The concepts of Edmontoniinae and Edmontoniidae are not in modern use. Edmontonia has been found as a close relative of Panoplosaurus in phylogenetic analysis, including in the 2018 phylogenetic analysis of Rivera-Sylva and colleagues shown below; limited to the relationships within Panoplosaurini . Animantarx Panoplosaurus Patagopelta Texasetes Denversaurus Edmontonia longiceps Edmontonia rugosidens The large spikes were probably used between males in contests of strength to defend territory or gain mates. The spikes would also have been useful for intimidating predators or rival males, passive protection, or for active self-defense. The large forward pointing shoulder spikes could have been used to run through attacking theropods. Carpenter suggested that

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4992-429: The condition does not involve this protrusion it is known as spina bifida occulta . Sometimes all of the vertebral arches may remain incomplete. Another, though rare, congenital disease is Klippel–Feil syndrome , which is the fusion of any two of the cervical vertebrae. Spondylolisthesis is the forward displacement of a vertebra and retrolisthesis is a posterior displacement of one vertebral body with respect to

5088-402: The cranial zygapophyses and the caudal zygapophyses). The centrum of the vertebra can be classified based on the fusion of its elements. In temnospondyls , bones such as the spinous process , the pleurocentrum and the intercentrum are separate ossifications. Fused elements, however, classify a vertebra as having holospondyly. A vertebra can also be described in terms of the shape of the ends of

5184-403: The curvatures of the vertebral column. The articulating vertebrae are named according to their region of the spine. Vertebrae in these regions are essentially alike, with minor variation. These regions are called the cervical spine, thoracic spine, lumbar spine, sacrum, and coccyx. There are seven cervical vertebrae, twelve thoracic vertebrae, and five lumbar vertebrae. The number of vertebrae in

5280-447: The facet joints restricts the range of motion between the vertebrae. Underneath each pedicle is a small hole (enclosed by the pedicle of the vertebral below) called intervertebral foramen , which transmit the corresponding spinal nerve and dorsal root ganglion that exit the spinal canal. From top to bottom, the vertebrae are: For some medical purposes, adjacent vertebral regions may be considered together: The vertebral column

5376-525: The holotype of Borealopelta markmitchelli , preserves a nearly complete set of armor in life position, as well as the keratin covering and mineralized remains of the underlying skin, which indicate reddish pigments in a countershading pattern. The family Nodosauridae was erected by Othniel Charles Marsh in 1890, and anchored on the genus Nodosaurus . The clade Nodosauridae was first informally defined by Paul Sereno in 1998 as "all ankylosaurs closer to Panoplosaurus than to Ankylosaurus ,"

5472-399: The jaw anatomy and mechanics of these dinosaurs suggests they probably all occupied slightly different ecological niches in order to avoid direct competition for food in such a crowded eco-space. The only large predators known from the same levels of the formation as Edmontonia are the tyrannosaurids Gorgosaurus libratus and an unnamed species of Daspletosaurus . Edmontonia longiceps

5568-624: The known fauna. Along with much rarer ankylosaurians and pachycephalosaurs , all of these animals would have been prey for a diverse array of carnivorous theropods, including troodontids , dromaeosaurids , and caenagnathids . Adult Albertosaurus was the apex predator in this environment, with intermediate niches possibly filled by juvenile albertosaurs. Panoplosaurini Acanthopholididae Nopcsa , 1902 Acanthopholidae Nopcsa, 1917 ? Hylaeosauridae Nopcsa, 1902 Palaeoscincidae Nopcsa, 1918 Panoplosauridae Nopcsa, 1929 Struthiosauridae Kuhn, 1966 Nodosauridae

5664-484: The larger spikes of AMNH 5665 indicated this was a male specimen, a case of sexual dimorphism . However, he admitted the possibility of ontogeny , older individuals having longer spikes, as the specimen was relatively large. Traditionally it had been assumed that to protect themselves from predators, nodosaurids like Edmontonia might have crouched down on the ground to minimize the possibility of attack to their defenseless underbelly, trying to prevent being flipped over by

5760-536: The length of the body, but to the rear the long axis of these osteoderms gradually rotates sideways, their keels ultimately running transversely. Rosettes are lacking. The configuration of the tail armour is unknown. The larger plates of all body parts were connected by small ossicles. Such small round scutes also covered the throat. In 1915, the American Museum of Natural History obtained the nearly complete, articulated front half of an armoured dinosaur, found

5856-449: The length of the column, which include the anterior and posterior longitudinal ligaments at the front and back of the vertebral bodies , the ligamentum flavum in deep to the laminae , the interspinous and supraspinous ligaments between spinous processes , and the intertransverse ligaments between the transverse processes . The vertebrae in the human vertebral column is divided into different body regions , which correspond to

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5952-432: The length of the vertebral column along the front and back of the vertebral bodies. The interspinous ligaments connect the adjoining spinous processes of the vertebrae. The supraspinous ligament extends the length of the spine running along the back of the spinous processes, from the sacrum to the seventh cervical vertebra . From there it is continuous with the nuchal ligament . The striking segmented pattern of

6048-403: The locations of other parts of human anatomy, such as the positions of organs . The general structure of vertebrae in other animals is largely the same as in humans. Individual vertebrae are composed of a centrum (body), arches protruding from the top and bottom of the centrum, and various processes projecting from the centrum and/or arches. An arch extending from the top of the centrum is called

6144-408: The lumbar region, by narrower intervals in the neck, and are closely approximated in the middle of the thoracic region. Occasionally one of these processes deviates a little from the median line — which can sometimes be indicative of a fracture or a displacement of the spine. On either side of the spinous processes is the vertebral groove formed by the laminae in the cervical and lumbar regions, where it

6240-405: The mechanisms involved in vertebral segmentation are conserved across vertebrates. In humans the first four somites are incorporated in the base of the occipital bone of the skull and the next 33 somites will form the vertebrae, ribs, muscles, ligaments and skin. The remaining posterior somites degenerate. During the fourth week of embryogenesis , the sclerotomes shift their position to surround

6336-480: The museum. Bakker described the skull as being much wider at the rear than Edmontonia specimens. However, later workers explained this by its being crushed, and considered the taxon a junior synonym of Edmontonia longiceps . The Black Hills Institute has referred a skeleton from the Lance Formation to Denversaurus , nicknamed "Tank". It has the inventory number BHI 127327. New research indicates that it

6432-418: The name Edmontonia . In 2010, G.S. Paul suggested that E. rugosidens was the direct ancestor of Edmontonia longiceps and the latter was again the direct ancestor of E. schlessmani . C.M. Sternberg originally did not provide a classification of Edmontonia . In 1930, L.S. Russell placed the genus in the Nodosauridae , which has been confirmed by subsequent analyses. Edmontonia was generally shown to be

6528-423: The next vertebral body fits. Even these patterns are only generalisations, however, and there may be variation in form of the vertebrae along the length of the spine even within a single species. Some unusual variations include the saddle-shaped sockets between the cervical vertebrae of birds and the presence of a narrow hollow canal running down the centre of the vertebral bodies of geckos and tuataras , containing

6624-405: The number of cervical vertebrae can range from a single vertebra in amphibians to as many as 25 in swans or 76 in the extinct plesiosaur Elasmosaurus . The dorsal vertebrae range from the bottom of the neck to the top of the pelvis . Dorsal vertebrae attached to the ribs are called thoracic vertebrae, while those without ribs are called lumbar vertebrae. The sacral vertebrae are those in

6720-446: The opposite, possessing anterior convexity and posterior concavity. They are found in salamanders, and in some non-avian dinosaurs. Heterocoelous vertebrae have saddle -shaped articular surfaces. This type of configuration is seen in turtles that retract their necks, and birds, because it permits extensive lateral and vertical flexion motion without stretching the nerve cord too extensively or wringing it about its long axis. In horses,

6816-423: The pelvic region, and range from one in amphibians, to two in most birds and modern reptiles, or up to three to five in mammals. When multiple sacral vertebrae are fused into a single structure, it is called the sacrum. The synsacrum is a similar fused structure found in birds that is composed of the sacral, lumbar, and some of the thoracic and caudal vertebra, as well as the pelvic girdle . Caudal vertebrae compose

6912-418: The posterior part of one somite fuses to the anterior part of the consecutive somite during a process termed resegmentation. Disruption of the somitogenesis process in humans results in diseases such as congenital scoliosis. So far, the human homologues of three genes associated to the mouse segmentation clock, (MESP2, DLL3 and LFNG), have been shown to be mutated in cases of congenital scoliosis, suggesting that

7008-417: The posterior surface by the articular processes in the cervical and thoracic regions and by the transverse processes in the lumbar region. In the thoracic region, the sides of the bodies of the vertebrae are marked in the back by the facets for articulation with the heads of the ribs. More posteriorly are the intervertebral foramina, formed by the juxtaposition of the vertebral notches, oval in shape, smallest in

7104-478: The rainy season began. Edmontonia rugosidens existed in the upper section of the Dinosaur Park Formation , about 76.5–75 million years ago. It lived alongside numerous other giant herbivores, such as the hadrosaurids Gryposaurus , Corythosaurus and Parasaurolophus , the ceratopsids Centrosaurus and Chasmosaurus , and ankylosaurids Scolosaurus and Dyoplosaurus Studies of

7200-542: The sacrovertebral articulation, and ends at the point of the coccyx ; its concavity is directed downward and forward as a kyphotic curve. The thoracic and sacral kyphotic curves are termed primary curves, because they are present in the fetus . The cervical and lumbar curves are compensatory , or secondary , and are developed after birth. The cervical curve forms when the infant is able to hold up its head (at three or four months) and sit upright (at nine months). The lumbar curve forms later from twelve to eighteen months, when

7296-593: The same year by Barnum Brown in Alberta , Canada. In 1922, William Diller Matthew referred this specimen, AMNH 5381, to Palaeoscincus in a popular-science article, not indicating any particular species. It had been intended to name a new Palaeoscincus species in cooperation with Brown but their article was never published. Matthew also referred specimen AMNH 5665, the front of a skeleton found by Levi Sternberg in 1917. In 1930 Charles Whitney Gilmore referred both specimens to Palaeoscincus rugosidens . This species

7392-407: The second halfring a side spike was present, a separate triangular osteoderm pointing obliquely forward. In the third halfring over the shoulders, the two pairs of central segments are bordered on each side by a very large forward-pointing spike that is bifurcated, featuring a secondary point above the main one. A third large spike behind it points more sideways; a smaller fourth one, often connected to

7488-414: The shoulders on each side, the second of which was split into subspines in E. rugosidens specimens. Its skull had a pear -like shape when viewed from above. Its neck and shoulders were protected by three halfrings made of large keeled plates. In 1990, Kenneth Carpenter established some diagnostic traits for the genus as a whole, mainly comparing it with its close relative Panoplosaurus . In top view,

7584-439: The snout has more parallel sides. The skull armour has a smooth surface. In the palate, the vomer is keeled. The neural arches and neural spines are shorter than those of Panoplosaurus . The sacrum proper consists of three sacral vertebrae. In the shoulder girdle, the scapula and coracoid are not fused. Carpenter also indicated in which way the main species differed from each other. The type species, Edmontonia longiceps ,

7680-401: The spine is established during embryogenesis when somites are rhythmically added to the posterior of the embryo. Somite formation begins around the third week when the embryo begins gastrulation and continues until all somites are formed. Their number varies between species: there are 42 to 44 somites in the human embryo and around 52 in the chick embryo. The somites are spheres, formed from

7776-446: The spinous process of the seventh thoracic vertebra. This curve is known as a kyphotic curve. The lumbar curve is more marked in the female than in the male; it begins at the middle of the last thoracic vertebra, and ends at the sacrovertebral angle. It is convex anteriorly, the convexity of the lower three vertebrae being much greater than that of the upper two. This curve is described as a lordotic curve. The sacral curve begins at

7872-416: The tail, and the final few can be fused into the pygostyle in birds, or into the coccygeal or tail bone in chimpanzees (and humans ). The vertebrae of lobe-finned fishes consist of three discrete bony elements. The vertebral arch surrounds the spinal cord, and is of broadly similar form to that found in most other vertebrates. Just beneath the arch lies a small plate-like pleurocentrum, which protects

7968-415: The tail. The general structure of human vertebrae is fairly typical of that found in other mammals , reptiles , and birds ( amniotes ). The shape of the vertebral body does, however, vary somewhat between different groups. In humans and other mammals, it typically has flat upper and lower surfaces, while in reptiles the anterior surface commonly has a concave socket into which the expanded convex face of

8064-425: The third at the base, is directed obliquely to behind. The row of side spikes is continued to the rear but there the osteoderms are much lower, curving strongly to behind, with the point overhanging the rear edge. Gilmore had trouble believing that the shoulder spikes really pointed to the front as this would have greatly hampered the animal while moving through vegetation. He suggested that the points had shifted during

8160-1410: The traditional dichotomous split between nodosaurids and ankylosaurids, their analyses resulted in a paraphyletic grade of these taxa comprising the monophyletic clades Panoplosauridae, Polacanthidae and Struthiosauridae. These results are displayed in Topology B below. Corresponding clades are shown in matching colors for clarity, and ⊞ buttons can be clicked to expand nodes: Sauroplites Mymoorapelta Dongyangopelta Gastonia Gargoyleosaurus Hoplitosaurus Polacanthus Peloroplites Taohelong Sauropelta Acantholipan Nodosaurus Niobrarasaurus Ahshislepelta Tatankacephalus Silvisaurus CPC 273 ( Aguja Formation specimen) Hungarosaurus Europelta Pawpawsaurus Borealopelta Stegopelta Struthiosaurus languedocensis Struthiosaurus transylvanicus Struthiosaurus austriacus Animantarx Panoplosaurus Patagopelta Texasetes Denversaurus Edmontonia longiceps Edmontonia rugosidens Kunbarrasaurus Paw Paw juvenile Hylaeosaurus Liaoningosaurus Crichtonpelta Chuanqilong Cedarpelta Aletopelta Later-diverging ankylosaurids Sarcolestes Vertebral column There are around 50,000 species of animals that have

8256-413: The type genus Nodosaurus was required as an internal specifier. In formally defining Nodosauridae, Madzia and colleagues followed the previously established use for the clade, defining it as the largest clade including Nodosaurus textilis but not Ankylosaurus magniventris . As all phylogenies referenced included both Panoplosaurus and Nodosaurus within the same group relative to Ankylosaurus ,

8352-453: The upper eye socket rim in Edmontonia longiceps do not stick out as much as in E. rugosidens , combined with a more narrow, pointed snout in the former. Some E. rugosidens specimens are known that possess a "cheek plate" above the lower jaw. Contrary to that discovered with Panoplosaurus , it is "free-floating", not fused with the lower jaw bone. The vertebral column contains about eight neck vertebrae, about twelve "free" back vertebrae,

8448-463: The upper surface of the notochord , and below that, a larger arch-shaped intercentrum to protect the lower border. Both of these structures are embedded within a single cylindrical mass of cartilage. A similar arrangement was found in the primitive Labyrinthodonts , but in the evolutionary line that led to reptiles (and hence, also to mammals and birds), the intercentrum became partially or wholly replaced by an enlarged pleurocentrum, which in turn became

8544-449: The vertebrae consist of two cartilaginous tubes. The upper tube is formed from the vertebral arches, but also includes additional cartilaginous structures filling in the gaps between the vertebrae, and so enclosing the spinal cord in an essentially continuous sheath. The lower tube surrounds the notochord, and has a complex structure, often including multiple layers of calcification . Lampreys have vertebral arches, but nothing resembling

8640-409: The vertebral bodies found in all higher vertebrates . Even the arches are discontinuous, consisting of separate pieces of arch-shaped cartilage around the spinal cord in most parts of the body, changing to long strips of cartilage above and below in the tail region. Hagfishes lack a true vertebral column, and are therefore not properly considered vertebrates, but a few tiny neural arches are present in

8736-475: The vertebral column presents in the median line the spinous processes. In the cervical region (with the exception of the second and seventh vertebrae), these are short, horizontal, and bifid. In the upper part of the thoracic region they are directed obliquely downward; in the middle they are almost vertical, and in the lower part they are nearly horizontal. In the lumbar region they are nearly horizontal. The spinous processes are separated by considerable intervals in

8832-410: Was a horizontal oval and represented the bony external nostril, the entrance to the nasal cavity , the normal air passage. The more rounded second opening below and obliquely in front, was the entrance to a "paranasal" tract, running along the outer side of the nasal cavity, in a somewhat lower position. A study by Matthew Vickaryous in 2006 proved for the first time the presence of multiple openings in

8928-525: Was based on type specimen USNM 11868, a skeleton found by George Fryer Sternberg in June 1928. The specific name is derived from Latin rugosus , "rough", and dens , "tooth". In 1940, Loris Shano Russell referred all three specimens to Edmontonia , as an Edmontonia rugosidens . Meanwhile, the type species of Edmontonia , Edmontonia longiceps , had been named by Charles Mortram Sternberg in 1928. The generic name Edmontonia refers to Edmonton or

9024-482: Was covered with osteoderms , skin ossifications. The configuration of the armour of Edmontonia is relatively well known, much of it having been discovered in articulation. The neck and shoulder region was protected by three cervical halfrings, each consisting of fused rounded rectangular, asymmetrically keeled, bone plates. These halfrings did not have a continuous underlying bone band. The first and second halfrings each had three pairs of segments. Below each lower end of

9120-709: Was erected by Bakker in 1988 for a skull from the Late Maastrichtian Upper Cretaceous Lance Formation of South Dakota , specimen DMNH 468 found by Philip Reinheimer in 1922. This type specimen of Denversaurus is in the collections of the Denver Museum of Natural History (now the Denver Museum of Nature and Science ), Denver, Colorado for which the genus was named. The specific name honours Lee E. Schlessman, whose Schlessman Family Foundation sponsored

9216-433: Was further complicated in 1971, when Walter Preston Coombs Jr renamed both Edmontonia species, into Panoplosaurus longiceps and Panoplosaurus rugosidens respectively. The latter species, which due to its much more complete material has determined the image of Edmontonia , until 1940 thus appeared under the name of Palaeoscincus , and during the 1970s and 1980s was shown as "Panoplosaurus" until newer research revived

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