DINOSAURICON B


Dinosauricon inhoud WP https://tsjok45.wordpress.com/2012/09/05/dinosauricon-inhoud/

B

http://www.nhm.ac.uk/nature-online/life/dinosaurs-other-extinct-creatures/dino-directory/name/b/gallery.html

http://en.wikipedia.org/wiki/List_of_dinosaurs 

https://wikimediafoundation.org/wiki/Support_Wikipedia/en

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Bactrosaurus

Bactrosaurus or Bactrasaurus (which means ‘club-spined lizard’) was a large, plant-eating, duck-billed dinosaur (a lambeosaurid hadrosaurine), up to about 20 feet (6 m) long, weighing roughly 1500 kg. Its femur (thigh bone was 80 cm long. About six fragmentary Bactrosaurus fossils were found in Mongolia and China. It lived during the late-Cretaceous period, about 97-85 million years ago and was named by C.W. Gilmore in 1933.

The type species is B. johnsoni.

bactrosaurus

Bactrosaurus (Greek for “staff lizard”); Woodlands of Asia
Late Cretaceous (95-85 million years ago)
About 20 feet long and 2 tons    Herbivore 
Thick trunk; club-shaped spines on backbone

Bactrosaurus:

Among the earliest of all the hadrosaurs, or duck-billed dinosaurs–roaming the woodlands of Asia at least 10 million years before more famous descendants like Charonosaurus–Bactrosaurus is important because it possessed certain characteristics (such as a thick, squat body) more often seen in iguanodont dinosaurs. (Paleontologists believe that hadrosaurs and iguanodonts, which are both technically classified as ornithopods, evolved from a common ancestor). Unlike most hadrosaurs, Bactrosaurus seems to have lacked a crest on its head, and it also had a row of short spines growing out of its vertebrae that formed a prominent, skin-covered ridge along its back.

Bactrosaurus dinosaurio Bactrosaurus   

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Bagaceratops   

http://nl.wikipedia.org/wiki/Bagaceratops     

Bagaceratops (meaning “small horned face”) was a ceratopsian dinosaur about 3 feet (1 m) long. Bagaceratops weighed rouhghly 65 pounds (30 kg). It was a quadrupedal plant-eater with a short neck frill and a small horn on its snout. It lived in what is now Mongolia, China during the late Cretaceous period, about 70 million years ago.

It was described by Halszaka Osmólska in 1975. The type species is B. rozhdestvenskyi.

bagaceratops

Bagaceratops
http://www.dinosoria.com/bagaceratops.htm

Bagaceratops

Crâne de Bagaceratops. © dinosoria.com

Ce petit dinosaure de la famille des protocératopsidés représente une autre ramification de la principale branche d’évolution des dinosaures à cornes.
Bagaceratops vivait en Asie au Crétacé supérieur. Ce dinosaure de la formation Khermeen Tsav, en Mongolie, a été décrit en 1975.
Bagaceratops mesurait environ 1 mètre de long. Plusieurs crânes ont été retrouvés ainsi que des squelettes relativement bien conservés.

Son corps, trapu et lourd, avec une longue queue, était soutenu par des membres puissants, pourvus de 5 orteils à l’avant et de 4 à l’arrière.

Bagaceratops possède plusieurs caractéristiques qui se développeront chez les dinosaures à cornes ultérieurs.
L’arrière de son crâne est orné d’une crête osseuse proéminente, précurseur de la grande collerette des cératopsidés.

Ses joues présentent une saillie en forme de feuille, la partie du bouclier céphalique des cératopsidés.

Il avait en outre une vraie corne, certes courte, au milieu du museau. De plus, la partie supérieure de son bec est édentée.
D’autres membres de la même famille ont des dents, ce que l’on considère comme un trait primitif.
En dépit de ses caractéristiques évoluées, Bagaceratops n’est probablement pas l’ancêtre direct des dinosaures à cornes.

Classification

Ornithischia. Genasauria. Cerapoda. Marginocephalia Ceratopsia. Neoceratopsia .
Bagaceratops « petite face à cornes »
Bagaceratops Rozhdestvenski

auteur : V.Battaglia (26.01.2006)

[image]

http://ombdinotopia.proboards.com/index.cgi?board=dinotopia&action=display&thread=360&page=9

bagaceratops

Bagaceratops rozhdestvenskyi

Bagaceratops

Fossile de Bagaceratops. © dinosoria.com

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Bagaraatan

(meaning “small hunter” ) was a speedy, bipedal, meat-eating dinosaur (an earlycoelurosaur). This theropod was about 11.5 feet (3.5 m) long and dates from the late Cretaceous period. An incomplete skeleton was found in Mongolia and was named by paleontologist Osmolska in 1996. The type species is B. ostromi.

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Bahariasaurus  was a theropod dinosaur (perhaps a carnosaur) about 20-40 feet (6-12 m) long, weighing about 4 tonnes. It was a bipedal meat-eater from what is now Egypt. It lived during the Cretaceous period, about 109 to 95 million years ago. It was named by Stromer in 1934.

The type species is B. ingens. The only known fossil was destroyed in World War II.

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Balaur (dinosaur)

balaur_bondoc_infographic_by_teratophoneus-d4toh21

balaur bondoc foot

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http://www.wired.com/wiredscience/2010/08/balaur-bondoc/

PNAS-2010-Csiki-15357-61[1] Balaur

Basic CMYK

Balaur_bondoc  holotype

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Bambiraptor

BAMBIRAPTOR OR BAMBI –> Bambiraptor (also known as Bambi) was a juvenile coelurosaur, an advanced theropod (meat-eating dinosaur). This small predator was originally thought to be a juvenile Velociraptor or perhaps Saurornitholestes langstoni. It was a small, fast, meat-eating dromaeosauriddinosaur from the late Cretaceous period. Bambiraptor was about 3 feet (1 m) long and may have weighed about 7 pounds (3 kg). It had a deadly, sickle-shaped toe claw on the second toe of its foot. Bambiraptor was found in the upper Two Medicine Formation, Montana, USA. The nearly complete, fossilized skeleton was found in a dinosaur bonebed, near a Maiasaura skull. Bambiraptor was named by Burnham, Derstler, Currie, Bakker, Zhou, and Ostrom, 2000.

-The type species is Bambiraptor feinbergi.

bambiraptor

bambiraptor

Malgré ses petites proportions, Bambiraptor est un redoutable tueur. Son squelette très bien conservé a été découvert aux Etats-Unis. Bambiraptor feinbergorum ne mesurait que 91 cm de long dont 50 cm rien que pour la queue.

Sa tête de 12 cm se situait à environ 35 cm du sol. Malgré ses dimensions réduites, ce dinosaure est un chasseur redoutable aux griffes puissantes et aux bras allongés. Il courait certainement très vite pour attraper ses proies.

Ses petites dents, tranchantes comme des lames de rasoir, lui permettaient de découper sans difficulté la chair des lézards, serpents, mammifères et peut-être des bébés dinosaures. Bien qu’aucune trace de peau n’a été retrouvée, les chercheurs pensent qu’il était recouvert de plumes, certainement colorées.

Bambiraptor est sans doute le chaînon le plus convaincant entre les dinosaures et les oiseaux.

Bambiraptor

Bambiraptor. © dinosoria.com

Bambiraptor est l’un des plus petits dinosaures connus, même si Microraptor, détient le record. C’est Bambi de Walt Disney qui a donné son nom à ce dinosaure. Les chercheurs ont l’habitude de donner un surnom aux squelettes qu’ils trouvent. Etrange qu’ils aient conservé celui-là pour un aussi dangereux reptile.

Les fossiles de Bambiraptor feinbergorum ont été mis au jour dans le Montana en 1994. Cependant, l’espèce n’a été décrite qu’en 2000.

V. Battaglia (12.2003)

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Batrachosaurus    —>   GEEN  REPTIEL  

Batrachosaurus is een geslacht van uitgestorven amfibieën uit het Trias. Fossielen van dit waterbewonende roofdier zijn gevonden in Zuid-Afrika. Batrachosaurus had een brede, platte kop met grote ogen. De poten waren relatief kort. De lange tanden wijzen erop dat vis het hoofdvoedsel was.

Batrachotomus_kupferzellensis

Barapasaurus (meaning “big-legged lizard”) was a sauropod (a long-necked, long-tailed, small-headed, short-legged giant). It was an herbivore, a plant-eater that was about 60 feet (20 m) long, weighing roughly 48400 kg. The femur (thigh bone) is 5.5 ft (1.70 m) long. Barapasaurus lived during the early Jurassic period, about 208 to 188 million years ago. 6 partial skeletons have been found in Southern India’s Godavari Valley, but no skulls or feet have been found. It ay belong to the family vulcanodintidae, but this is unsure. Barapasaurus was named by Jain, Kutty, Roy-Chowdhury & Chatterjee in 1975. The type species is B. tagorei.

Barosaurus (meaning “heavy lizard”) was a diplodocid sauropod (a long-necked, long-tailed, small-headed, short-legged giant). It was an herbivore, a plant-eater. It was huge and slow-moving, perhaps over 60 to 88 feet (20-27 m) long, weighing roughly 40000 kg. Its femur (thigh bone) was 8.2 ft (2.52 m) long. Its primary defense against predators was its size. Barosaurus lived during the late Jurassic period, about 156 to 145 million years ago. Its fossils have been found in western North America and East Africa. Barosaurus was named by paleontologistOthniel C. Marsh in 1890. The type species is B. lentus

  • File:Barosaurus mount 1.jpg
  • A view from below of the rearing Barosaurus mounted in the American Museum of Natural History in New York City

    barapasaurus
    Barosaurus May 18, 2011

    Filed under: Sauropoda — muzillu @ 11:49 am
    Huge and long-necked, Barosaurus also had a lengthy tail which it wielded as a weapon against enemies. It lived in herds, which was also useful for defence against predators. Like all members of the sauropod group, it had one large, curved claw on the inner toe of its front foot.
    This species is known from five partial skeletons from the Morrison Formation, three of them in Dinosaur Natural Monument in Utah, USA. The African species, until recently known as Gigantosaurus, was part of the Tendaguru fauna, and known from four skeletons. The rearing skeleton of Barosaurus in the American Museum of Natural History, at a height of 15m, is the tallest mounted skeleton in the world, only made possible by modern techniques of producing casts of fossil bones in lightweight materials.
    barosaurus africanus
    Barosaurus  Gordo

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    Barosaurus Lentus
    Factbox
    Name: Barosaurus, meaning ’slow heavy reptile’
    Size: up to 27m long
    Food: plants and leaves
    Lived: about 150-140 million years ago in the Jurassic Period in western North America
    The bones in Barosaurus’ long neck were hollow and light, which meant it could lift its head to feed quite easily. If its neck bones had been solid, it would have been too heavy to lift. Barosaurus is very much like Diplodocus – indeed the limb bones are indistinguishable between the two genera – but its tail bones are shorter and its neck bones at least one-third longer, one of which is 1m long. The two genera were in fact about the same size overall. It was longer than Apatosaurus, but its skeleton was less robust.
    The way that Barosaurus and the other diplodocids were balanced at the hips suggested that they could rear up on their hind legs for feeding or for scaring off predators.
    Barosaurus was once thought to have held its head like a giraffe. In order to pump blood up to the brain – a height of around 12m, 10m above the heart – the heart would have had to have weighed about 1.5 tonnes. The larger a heart, the slower it beats. A 1.5 tonne heart would beat so slowly that the blood would run back down the neck before the next beat. In fact, the length of the neck has led some palaeontologists to suggest that there were several hearts along its length, to enable the blood to reach the brain when it was feeding from high trees.
    However, a recent theory was postulated that, like a giraffe, it had arterial valves in its neck. These operate in response to differentials in fluid pressure, allowing the blood to be pumped up the neck but preventing most of it from falling back down. More recent computer modelling of diplodocids like Barosaurus has shown that they probably habitually held their necks more or less horizontally, thus restricting the problem to whether the animal reared up on its hind legs or not.

    Barosaurus (“zwaar reptiel”) was een sauropode dinosauriër behorend tot de groep van de Diplodocidae die leefde gedurende het midden-laat Jura en planten at. Hij leefde vermoedelijk in kuddes.

    De vijand van Barosaurus was vooral Allosaurus, een van de grootste vleeseters uit die tijd. Het dier kon zich prima verdedigen. Met zijn lengte van 23 tot 25 meter en zijn hoogte van 16 meter was dit een groot dier. Zijn grootte was al een verdedigingsmiddel, maar ook zijn staart was een prima wapen. Als hij bedreigd werd, richtte hij zich vermoedelijk op zijn achterpoten op, klaar om zich te beschermen. Hij kon vijanden vertrappen. Barosaurus kenmerkt zich door een extreem lange nek die volgens sommigen diende om hoog in de bomen te eten, volgens anderen om tijdens het horizontaal de bodem begrazen een zo groot mogelijk bereik te hebben.

    Er worden twee verschillende soorten onderscheiden: Barosaurus lentus (in 1890 beschreven door Othniel Charles Marsh) en Barosaurus africanus. Deze laatste soort behoort wellicht to het geslacht Tornieria.

    In het American Museum of Natural History in New York City staan drie skeletten: twee van Barosaurus en één allosaurus. De volwassen barosaurus staat op haar achterpoten. Ze verdedigt haar jong tegen een allosaurus.

    Sauropoda: Diplodocidae: Barosaurus: Barosaurus Lentus
    Barosaurus  ‘heavy lizard’ (Greek barys/βαρυς meaning ‘heavy’ and saurus/σαυρος meaning ‘lizard’) was a giant, long-tailed, long-necked, plant-eating dinosaur closely related to the more familiar Diplodocus. Remains have been found in the Morrison Formation from the Upper Jurassic Period, along with five other sauropods: Diplodocus, Apatosaurus, Camarasaurus, Brachiosaurus andHaplocanthosaurus, as well as the predator Allosaurus and armored dinosaur Stegosaurus.
    Barosaurus was an enormous animal, with some adults measuring more than 26 meters  in length and weighing more than 20 metric tons (22 short tons). Barosaurus was differently proportioned than its close relative Diplodocus, with a longer neck and shorter tail, but was about the same length overall. It was longer than Apatosaurus, but its skeleton was less robust.

    Sauropod skulls are rarely preserved, and scientists have yet to discover a Barosaurus skull. Related diplodocids like Apatosaurus and Diplodocus had long, low skulls with peg-like teeth confined to the front of the jaws.
    Most of the distinguishing skeletal features of Barosaurus were in the vertebrae, although a complete vertebral column has never been found. Apatosaurus and Diplodocus both had 15 cervical (neck) and 10 dorsal (trunk) vertebrae, while Barosaurus had only 9 dorsals.

    A dorsal may have been converted into a cervical vertebra, for a total of 16 vertebrae in the neck. Barosaurus cervicals were similar to those of Diplodocus, but some were up to 50% longer.

    The neural spines protruding from the top of the vertebrae were neither as tall or as complex in Barosaurus as they were in Diplodocus. In contrast to its neck vertebrae, Barosaurus had shorter caudal (tail) vertebrae than Diplodocus, resulting in a shorter tail. The chevron bones lining the underside of the tail were forked and had a prominent forward spike, much like the closely-related Diplodocus.

    The tail probably ended in a long whiplash, much like Apatosaurus, Diplodocus and other diplodocids, some of which had up to 80 tail vertebrae.

    The limb bones of Barosaurus were virtually indistinguishable from those of Diplodocus.

    Both were quadrupedal, with columnar limbs adapted to support the enormous bulk of the animals. Barosaurus had proportionately longer forelimbs than other diplodocids, although they were still shorter than most other groups of sauropods. There was a single carpal bone in the wrist, and the metacarpals were more slender than those of Diplodocus. Barosaurus feet have never been discovered, but like other sauropods, it would have been digitigrade, with all four feet each bearing five small toes. A large claw adorned the inside digit on the manus (forefoot) while smaller claws tipped the inside three digits of the pes (hindfoot).

    Barosaurus is a member of the sauropod family Diplodocidae, and sometimes placed with Diplodocus in the subfamily Diplodocinae. Diplodocids are characterized by long tails with over 70 vertebrae, shorter forelimbs than other sauropods, and numerous features of the skull. Diplodocines like Barosaurus and Diplodocus have more slender builds and longer necks and tails than apatosaurines, the other subfamily of diplodocids.

    The systematics (evolutionary relationships) of Diplodocidae are becoming better established.

    Diplodocus has long been regarded as the closest relative of Barosaurus. Barosaurus is monospecific, containing only the type species, B. lentus, while at least three species belong to the species Diplodocus.

    Another diplodocid genus, Seismosaurus, is considered by many paleontologists to be a junior synonym of Diplodocus as a possible fourth species.

    Tornieria (formerly “Barosaurus” africanus) and Australodocus from the famous Tendaguru Beds of Tanzania in eastern Africa have also been classified as diplodocines.

    With its elongated neck vertebrae, Tornieria may have been particularly closely related to Barosaurus.

    The other subfamily of diplodocids is Apatosaurinae, which includes Apatosaurus (aka brontosaurus ? ) and Supersaurus.

    The early genus Suuwassea is considered by some to be an apatosaurine, while others regard it as a basal member of the superfamily Diplodocoidea. Diplodocid fossils are found in North America, Europe, and Africa. More distantly related within Diplodocoidea are the families Dicraeosauridae and Rebbachisauridae, found only on the southern continents.

    The first Barosaurus remains were discovered in the Morrison Formation of South Dakota by Othniel Charles Marsh and John Bell Hatcher of Yale University in 1889. Only six tail vertebrae were recovered at that time, forming the type specimen (YPM 429) of a new species, which Marsh named Barosaurus lentus, from the Classical Greek words βαρυς/barus (“heavy”) and σαυρος/sauros (“lizard”), and the Latin word lentus (“slow”). The rest of the type specimen was left in the ground under the protection of the landowners until it was collected nine years later, in 1898, by Marsh’s assistant, George Wieland. Marsh described these new remains, consisting of vertebrae, ribs and limb bones, and classified Barosaurus as a diplodocid for the first time. In his last published paper before his death, Marsh named two smaller metatarsals found by Wieland as a second species, B. affinis, but this has long been considered a junior synonym of B. lentus.
    After the turn of the 20th century, Pittsburgh’s Carnegie Museum of Natural History sent fossil hunter Earl Douglass to Utah to excavate the Carnegie Quarry in what is now known as Dinosaur National Monument.

    Four neck vertebrae, each one meter (3 feet) long, were collected in 1912 near a specimen of Diplodocus, but a few years later, William Jacob Holland realized they belonged to a different species.

    Meanwhile, the type specimen of Barosaurus had finally been prepared at Yale and was fully described by Richard Swann Lull in 1919. Based on Lull’s description, Holland referred the vertebrae (CM 1198), along with a second partial skeleton found by Douglass in 1918 (CM 11984), to Barosaurus. This second Carnegie specimen remains in the rock wall at Dinosaur National Monument and was not fully prepared until the 1980s.
    The most complete specimen of Barosaurus was excavated from the Carnegie Quarry in 1923 by Douglass, now working for the University of Utah after the death of U.S. Steel founder Andrew Carnegie, who had been financing Douglass’ earlier work in Pittsburgh.

    Material from this specimen was spread across three institutions. Most of the back vertebrae, ribs, pelvis, hindlimb and most of the tail stayed at the University of Utah, while the neck vertebrae, some back vertebrae, the shoulder girdle and forelimb were shipped to the National Museum of Natural History in Washington D.C., and a small section of tail vertebrae ended up in the Carnegie Museum in Pittsburgh.

    In 1929, Barnum Brown arranged for all of the material to be shipped to the American Museum of Natural History in New York City, where it remains today. A cast of this specimen (AMNH 6341) was controversially mounted in the lobby of the American Museum, rearing up to defend its young from a marauding Allosaurus.
    More recently, more vertebrae and a pelvis were recovered in South Dakota. This material (SDSM 25210 and 25331) is stored in the collection of the South Dakota School of Mines and Technology in Rapid City.

    In 2007, paleontologist David Evans discovered a partial Barosaurus skeleton forgotten in the collection of the Royal Ontario Museum in Toronto, where he had recently become a curator.

    Earl Douglass excavated this specimen (ROM 3670) at the Carnegie Quarry in the early 20th century and the ROM acquired it in a 1962 trade with the Carnegie Museum. The specimen never made it out on exhibit and instead remained in storage until its rediscovery 45 years later. It is now one of the centerpieces of the dinosaur exhibit at the ROM. John McIntosh believes that this skeleton is the same individual represented by four neck vertebrae (CM 1198) in the collection of the Carnegie Museum.
    In 1907, German paleontologist Eberhard Fraas discovered the skeletons of two sauropods on an expedition to the Tendaguru Beds in German East Africa (now Tanzania). He classified both specimens in the new genus Gigantosaurus, with each skeleton representing a new species (G. africanus and G. robustus). However, this genus name had already been given to the fragmentary remains of a sauropod from England. Both species were moved to a new genus, Tornieria, in 1911. Upon further study of these remains and many other sauropod fossils from the hugely productive Tendaguru Beds, Werner Janensch moved the species once again, this time to the North American genus Barosaurus. In 1991, “Gigantosaurus” robustus was recognized as a titanosaur and placed in a new genus, Janenschia, as J. robusta. Meanwhile, many paleontologists suspected “Barosaurus” africanus was also distinct from the North American genus, which was confirmed when the material was redescribed in 2006. The African species, although closely related to Barosaurus lentus and Diplodocus from North America, is now once again known as Tornieria africana.

    Paleoecology
    Barosaurus remains are limited to the Morrison Formation, which is widespread in the western United States between the Great Plains and Rocky Mountains. Radiometric dating agrees with biostratigraphic and paleomagnetic studies, indicating that the Morrison was deposited during the Kimmeridgian and early Tithonian stages of the Late Jurassic Period, or approximately 155 to 148 million years ago. Barosaurus fossils are found in late Kimmeridgian sediments, around 150 million years old.
    The Morrison Formation was deposited in floodplains along the edge of the ancient Sundance Sea, an arm of the Arctic Ocean which extended southward to cover the middle of North America as far south as the modern state of Colorado. Due to tectonic uplift to the west, the sea was receding to the north, and had retreated into what is now Canada by the time Barosaurus evolved. The sediments of the Morrison were washed down out of the western highlands, which had been uplifted during the earlier Nevadan orogeny and were now eroding. Very high atmospheric concentrations of carbon dioxide in the Late Jurassic led to high temperatures around the globe, due to the greenhouse effect. One study, estimating CO2 concentrations of 1120 parts per million, predicted average winter temperatures in western North America of 20 °C (68 °F) and summer temperatures averaging 40–45 °C (104–113 °F). A more recent study suggested even higher CO2 concentrations of up to 3180 parts per million. Warm temperatures that led to significant evaporation year-round, along with possible rain shadow effect from the mountains to the west, led to a semi-arid climate with only seasonal rainfall.

    Posted Image

    Key words  Diplodocus Apatosaurus Camarasaurus Brachiosaurus Allosaurus Stegosaurus

    http://www.youtube.com/watch?v=Lz6oL-ELwZQ&feature=player_embedded

  • Barrosasaurus

BARSBOLDIA (named for Rinchen Barsbold) was a duck-billed dinosaur (a lambeosaurine hadrosaur) about 30 feet (10 m) long, weighing roughly 6500 kg. It was a quadrupedal plant-eater with a hollow crest and tall spines on its back vertebrae (which may have formed a fin on its back). It lived in what is now Mongolia during the late Cretaceous period, about 70 million years ago. The type species is B. sicinskii. It was named by Maryanska and Osmolska in 1981. This is a doubtful genus since it is so poorly known.

Baryonyx (meaning “heavy claw”) was an unusual theropod dinosaur (a carnivore) from the earlyCretaceous period, about 125 million years ago. It had crocodile-like jaws, a low-slung-body, and it ate fish. It was about 31 ft (9.5 m) long and weighed roughly 1700 kg.

http://spinosauridae.fr.gd/Baryonyx-walkeri.htm
http://qilong.wordpress.com/2010/05/21/croc-snouted-lizards-a-mystery-in-gadoufaoua/

Baryonyx was the first carnivorous dinosaur to be discovered in England. It was an unusual theropod with huge foot-long claws on its hands. Most theropods had S-shaped necks, but Baryonyx had a long straight one that was fairly inflexible. The design of its hips and pelvis suggests that it was bipedal for the purposes of walking from place to place. However, its forelimbs were absurdly large for a theropod, suggesting that it also spent much of its time on all fours. It had a long long tail and a low-slung body.
The skull was set at an acute angle, not the 90° angle common in similar dinosaurs. The long jaw was distinctly crocodilian, and had 96 teeth, twice as many as its relatives. Sixty-four of the teeth were placed in the lower jaw (mandible), and 32 large ones in the upper (maxilla). The snout probably bore a small but distinctive crest.
The crocodile-like jaws and large number of finely serrated teeth suggested to scientists that Baryonyx was a fish-eater. As confirmation, a number of scales and bones from the fish Lepidotes were also discovered in the body cavity. Some believe that Baryonyx would sit on a riverbank, resting on its powerful front legs, and then sweep fish from the river with its powerful striking claw. This is the same fishing technique used by modern grizzly bears. The long but low stance and angled head support this theory. Interestingly, Iguanodon bones were found with the Baryonyx skeleton, suggesting that it may have scavenged any extra meat it could find.

Baryonyx was discovered by William Walker, an amateur fossil hunter, in 1983. He found an enormous claw sticking out the side of a clay pit. He retrieved the specimen, which was surprisingly intact. He took it to the Natural History Museum in London, where it was examined by Alan J. Charig and Angela C. Milner.
About 70 percent of the skeleton was later recovered, including the skull. The bones were fossilized in an unnatural position, so the paleontologists reconstructing it placed them on the front feet because these legs were so powerful. The bone structure suggests a massive bulk of muscle ran down the sides of these front legs. It was and is the only known specimen and it seems to have been a juvenile, so the upper limits of its size are still unknown..
Charig and Milner published their description of the type species, B. walkeri, in 1986, and named it after Walker. There is only one specimen of Baryonyx, so there is little debate about classification. There is a similarity to the tetanuran Becklespinax, but there is no evidence that Baryonyx had similar elongated spines on the back of its neck.
Baryonyx was the only known piscivorous (fish-eating) dinosaur until the discovery of the closely-related Suchomimus. It was another crocodile-like fish-eater. Described in 1998, it was placed in the same subfamily (Baryonyichae). It has recently been suggested that Suchomimus tenerensis should be redefined as Baryonyx tenerensis due to similarities in their vertebrae.

Baryonyx

Parmi les dinosaures connus, Baryonyx walkeri est l’un des plus rares. Le premier spécimen a été retrouvé en 1983 dans une carrière du Sud de l’Angleterre.

L’anatomie de Baryonyx “Griffes puissantes ” est très différente de celle des autres dinosaures. Il possédait un cou flexible et de longues mâchoires. Baryonyx possédait les plus grandes griffes jamais trouvées parmi les fossiles de dinosaures. Cette serre recourbée, de 31 cm, représentait une arme redoutable

De profil, le crâne de Baryonyx ressemble à celui du crocodile. Cette caractéristique est commune à toutes les espèces de la famille des Spinosauridés.

On pense qu’il attrapait des poissons avec son museau long et étroit car on a retrouvé des écailles de poissons dans son squelette.

Baryonyx

Crâne d’un baryonyx. © dinosoria.com

De plus, ses narines sont situées à 10 cm du bout de son museau.
On peut donc en déduire, qu’il pouvait plonger son museau dans l’eau tout en continuant à respirer.

Il se tenait la tête basse et le cou droit, et non penché comme beaucoup d’autres théropodes.

Baryonyx

Ce Baryonyx se serait noyé dans un lac. © dinosoria.com

Il ne dédaignait pas la viande cependant car des petits os dans son estomac ont été identifiés comme ceux d’un jeune iguanodon.

Griffe de Baryonyx

Griffe de Baryonyx. © dinosoria.com

La taille de Baryonyx walkeri est estimée à 9 mètres. Ce dinosaure vivait au Crétacé inférieur.

Classification: Saurischia Theropoda Tetanurae Spinosauroidae Baryonychidae

Charig & Milner, 1986

V.Battaglia (11.2003)

Spinosauridés

baryonyx

baryonyx walkeri

.Baryonix

°

BASUTODON Basutodon (meaning “Basuto [former name of Lesotho, South Africa] tooth”) is a dubious genus of reptile that may or may not be dinosaurian. Fossil teeth that date from the Triassic period were found in South Africa. Basutodon was named by paleontologist von Huene in 1932.

The type species is B. ferox.

_

becklespinax

beipiaosaurus

Beipiaosaurus 
http://www.dinosaurus.net/genera/BBB/beipiaosaurus.htm
http://en.wikipedia.org/wiki/Beipiaosaurus

© Académie chinoise des Sciences.

(bron
http://www.volkskrant.nl/wetenschap/article1120042.ece/Dinosaurusfossiel_onthult_vroegste_veer
Ben van Raaij 13 januari 2009)

Twee dinosaurusfossielen uit Liaoning (Noord-Oost China) laten afdrukken zien van de vroegst bekende primitieve veren.
Een tweede soort veren werden eveneens gevonden ;dat waren waarschijnlijk sierveren .

Dat staat in een bijdrage van Chinese paleontologen  in het Amerikaanse tijdschrift Proceedings of the National Academy of Sciences (PNAS). Het gaat om fossielen van twee Beipiaosauriërs ( die reeds enkelejaren geleden werden ontdekt ) Ze stammen uit het vroege Krijt en zijn 125 miljoen jaar oud.

De Beipiaosaurus was een therizinosaurus-achtige theropode.
Theropoden waren veelal vleesetende dino’s die op hun achterpoten liepen

.

The elongated, single filament feathers of Beipiaosaurus. The yellow arrows point to feathers on the head and neck (right) and tail (above)
(From: Xu et al. 2009).

  <

beipiaosaurus

X. Xu, X. Zheng, H. You (2009).
A new feather type in a nonavian theropod and the early evolution of feathers Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0810055106

vergelijk ook met

Het 1999 paper on Beipiaosaurus by XING XU *, ZHI-LU TANG & XIAO-LIN WANG
“A therizinosauroid dinosaur with integumentary structures from China”

*Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences in Beijing.

Het ene fossiel bezit korte, slanke veerdraden die lijken op die bij andere niet-vliegende dino’s zijn gevonden.
Het andere fossiel heeft veren van een tot nu toe geheel onbekend type: stevige, enkele pennen van ongebruikelijke lengte.

De onderzoekers denken met deze slanke draadachtige dons-veren (Elongated Broad Filamentous Feathers gedoopt) het evolutionair vroegste type veer te hebben gevonden, mede omdat alle andere tot nu toe gevonden dinoveren van een complexer, samengesteld type zijn.

De functie van de pinachtige veren is onduidelijk. Ze lijken ongeschikt om mee te vliegen of de lichaamstemperatuur mee te regelen, zoals het geval lijkt bij veel andere gevederde dinosauriërs.

De veren waren dan ook vooral bedoeld als versiering, denken de onderzoekers, mede omdat ze op plekken van het lichaam zitten (kop, nek, rug, staart) waar ook bij vogels, verre afstammelingen van de dinosauriërs, sierveren zitten.

http://www.sciencenews.org/view/generic/id/39830/description/Dinosaur_fossil_reveals_creature_of_a_different_feather


” …..Flight feathers on modern birds have a central shaft and stiff fibers, called barbs, that branch from that shaft.
Barbules, smaller fibers that branch from the barbs, are tipped with small hooks that latch on to adjacent barbs or barbules, stiffening the feather into a single vane…..

This arrangement is so complicated that many scientists theorize it could have evolved only once (SN: 8/18/01, p. 106).
But paleontologists have proposed that a variety of simpler structures — including peculiar, branched structures colloquially called “dinofuzz” — evolved before feathers.
Now, researchers have finally found an important yet long-missing piece of the feather lineage: single, unbranched filaments…..”


Zie ook
http://dracovenator.blogspot.com/2009/01/new-beipiaosaurus-beautifull-plumage.html
http://paleonews.wordpress.com/2009/01/13/2009-01-13-beipaosaurus-le-prime-piume-non-per-il-volo-beipaosaurus-feathers-for-show/

http://cas.bellarmine.edu/tietjen/Evolution/Fossil%20Record/a_therizinosauroid_dinosaur_with.htm

Figure 1 Beipiaosaurus inexpectus (V11559, holotype). Photograph (a)and outline (b) of the skeleton (broken lines indicate features preserved in impressions). The holotype was collected in 1996 by a farmer, Li Yinxian, from the famous Sihetun locality. It was later (1997) determined to be from the lower part of the Yixian Formation. According to communication with the collector, and consistent with the close proximity, preservation and proportions of the elements, all elements (including the integumentary structures) are from a single individual. V11559 includes the partial right dentary with dentition, right postorbital, right parietal, right nasal?, right prootic, a few cervicals and dorsals, an incomplete caudal, incomplete ribs, partial scapula, coracoids and furcula, partial humerus, radius and ulna, nearly complete hands, partial ilium, pubis and ischium, complete right femur, right tibia and right fibula, incomplete left femur, tibia and fibula, incomplete right foot. Some elements are represented by impressions.Sacral and most caudal vertebrae are missing. a, astragalus; c, cervical vertebra; ca, caudal vertebra; co, coracoids; d, dentary; dcI, distal carpal I; do, dorsal vertebra; f, femur; fi, fibula; fu, furcula; I-III, metacarpals I-III, I-1 to III-4, manual phalanges I-1 to phalanges III-4; il, ilium; is, ischium; lh, left humerus; lr, left radius; lu, left ulna; ?n, ?nasal; p, parietal; pe, pes; po, postorbital; pr, prootic; pu, pubis; r, rib; ?ra, ?radiale; rh, right humerus; rr, right radius; ru, right ulna; s, scapula; sl, semilunate distal carpal; t, tibia

Locality and horizon.

Sihetun locality near Beipiao, Liaoning, China. The lower part of the Yixian Formation, probably from the Lower Cretaceous based on latest radiometric evidence13.

Figure 2Beipiaosaurus inexpectusa, Nine right dentary teeth in medial view. Note the resorption pits and replacement teeth. b, A dentary tooth in lateral view. c, Close-up of the left semilunate carpal of V11559.d, Drawing of part of the right manus of V11559. Note the shape and position of the semilunate, which is very similar to that of birds17e, Drawing of the partially preserved right pes of V11559. f, Close-up of the first metatarsal of V11559. Note the proximally pinched theropod first metatarsal. The theropod first metatarsal is absent in other therizinosauroids, which has been argued as being strong evidence against the theropod affinities of therizinosauroids1.Additional abbreviations: mc I-III, metacarpals I-III; mt I-IV, metatarsals I-IV; pul, pedal ungual; r, radius; ra, radiale; ta, tarsal; u, ulna.

Natural History Museum
Show taxonomic details
Lengte
 tot 2 m Diet: alleseter


Periode: Lower Cretaceous (Laat- krijt ) Barremiaan -127-121 Ma


Vindplaats Peoples Republic of China Liaoning
http://nl.wikipedia.org/wiki/Liaoning

” De fossielen uit de Liaoning provincie zijn 120-125 miljoen jaar oud en stammen ( meestal) uit het Vroeg-Krijt, toen Liaoning een tropisch regenwoud moet zijn geweest. Veel fossielen tonen afdrukken van veren of haren.
De vondsten zijn gedaan in de Yixian- en de Jiufotang-Formatie uit de Jehol Groep. ” 

Een verenkleed is niet alleen aan vogels voorbehouden, maar was al in een veel vroeger evolutionair stadium en bij andere diersoorten uit de stamlijnen( en de collaterale verwanten )van de vogelvoorouders , aanwezig ….
Opzienbarend is deze nieuwe vondst dan ook niet :Paleontologen zijn er immers al langer van overtuigd dat zowel primitieve als moderne vogels direct afstammen van kleine en middelgrote vleesetende landdinosauriërs :
de Maniraptorae ,-150MY , tijdens het Jura

Beipiaosaurus

, een niet overdreven grote vleesetende dinosauriër met relatief grote klauwen, was 125 miljoen jaar geleden al uitgerust met een donzig verenkleed ___ trouwens ook aanwezig bij veel andere niet-aviale dino’s
( Misschien is deze dons wel te vergelijken met de haar-achtige – veren van de KIWI )

*Het grootste deel van zijn lichaam was bedekt met deze fijne donsveren( bestaande uit een schachtje met draadachtige vertakkingen:de zogenaamde baarden van de vlag ) Aangezien het reptiel geen vleugels had ( het kan dus geen vogel geweest zijn —> ook geen (loop) vogel die het vliegen heeft verloren (1 ) kunnen de veren geen rol gespeeld hebben bij eventuele pogingen om een vliegend bestaan te leiden.
Misschien speelden ze een belangrijke rol bij de isolatie en warmteregulering ( net als bij de andere gevederde dino’s )

* Het tweede (nu ontdekte )type lange en brede veren( maar zonder vertakkingen ) vervulden waarschijnlijk de rol van pronkobjecten : Als communicatiemiddel of lokmiddel voor seksueel receptieve vrouwtjes is zo’n opvallend verenrenkleed immers altijd handig.
Ook een dierlijk oog wil tenslotte wat.


(1)
*Loopvogels ( en pinguins ) zonder vliegvermogen bezitten altijd echte vleugels en altijd een bek ;
Vogels bezitten nooit een reptielenstaart en meestal geen volwaardige vleugelklauwen ( Hoatzin kuikens wel? )
* Sommige vogels bezitten veren maar vliegen niet …veren zijn dus niet noodzakelijk indicatoren van dieren met werkelijk vliegvermogen
* Deze Beipiaosaurus is geen vogel , maar een vertegenwoordiger van groepen die nauw verwant zijn met de vogels ( groepen van collaterale verwanten )
Velen uit die groepen ( bv. velociraptor ) bezaten veren , sommigen waren uitgerust met een “bek ” (oviraptor? ) sommigen bezaten een vogel-vorkbeen (= furricula )
Andere vertegenwoordigers (der kleinere theropoden) zijn ware mozaiken ( zoals de archeaopteryx —> vooral reptielstaart , tanden , en weliswaar vleugels maar ook vleugel-klauwen )
* De vogels stammen af van gevederde Maniraptorae …Niet omgekeerd

LINKS

zie ook  http://the_dinosauria.tripod.com/therizinosaurs.html

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bellusaurus

BIRDS   —>VOGELS  

http://en.wikipedia.org/wiki/Bird

File:Bird Diversity 2013.png

 

bolong

bonapartenykus  ultimus

borogovia

brachiosaurus

Image Copyright © 2005 Miles Kelly Publishing.

Brachiosaurus meaning “Arm Lizard”, from the Greek brachion/meaning ‘arm’ and sauros/σαυρος meaning ‘lizard’, was a genus of sauropod dinosaur which lived during the Late Jurassic Period. It was thus named because its forelimbs were longer than its hind limbs. One of the largest animals ever to walk the earth, it has become one of the most famous of all dinosaurs and is widely recognised worldwide.

For many decades, Brachiosaurus was the largest dinosaur known. It has since been discovered that a number of giant titanosaurians (Argentinosaurus, for example) surpassed Brachiosaurus in terms of sheer mass. More recently, another brachiosaurid, Sauroposeidon, has also been discovered; based on incomplete fossil evidence, it too is likely to have outweighed Brachiosaurus.

Brachiosaurus is often considered to be the largest dinosaur known from a relatively complete fossilized skeleton. However, the most complete specimens, including the Brachiosaurus in the Humboldt Museum of Berlin (excavated in Africa, the tallest mounted skeleton in the world), are members of the species B. brancai which some scientists consider to be part of a separate genus, Giraffatitan. The holotype material of the type species, B. altithorax. includes a sequence of seven posterior dorsal vertebrae, sacrum, proximal caudal vertebra, coracoid, humerus, femur and ribs: enough from which to estimate size.

Based on a complete composite skeleton, Brachiosaurus attained 25 metres (82 feet) in length and was probably able to raise its head about 13 metres (42 ft) above ground level. Fragmentary material from larger specimens indicates that it could grow 15% longer than this. Such material includes an isolated fibula HMN XV2 1340 cm in length and the brachiosaurid scapulocoracoid referred to Ultrasauros.

Brachiosaurus has been estimated to have weighed anywhere between 15 tonnes (Russell et al., 1980) and 78 tonnes (Colbert, 1962). These extreme estimates can be discarded as that of Russell et al. was based on limb-bone allometry rather than a body model, and that of Colbert on an outdated and overweight model. More recent estimates based on models reconstructed from osteology and inferred musculature are in the range 32 tonnes (Paul 1988) to 37 tonnes (Christiansen 1997). The 15% longer specimens hinted at above would have massed 48 to 56 tonnes.

From Wikipedia, the free encyclopedia


Brachiosaurus
 May 15, 2011

Filed under: Sauropoda —
Brachiosaurus was one of the largest and heaviest dinosaurs that ever lived. The top of a man’s head would have reached only to this giant creature’s knees. It had a huge body, a very long neck, a small head and a long tail.
The best-known Brachiosaurus skeleton in the world is now thought to be a different genus – Giraffatitan. However, an even bigger animal,Ultrasauros, found in the Dry Mesa Quarry in Colorado, is now regarded as a particularly big specimen of Brachiosaurus. The originalBrachiosaurus was discovered as two partial skeletons in the Morrison Formation near Fruita in Utah in 1900 by Elmer G. Riggs.

Factbox
Name: Brachiosaurus, meaning ‘tall-chested arm lizard’
Size: up to 23m long and 12m high
Food: leaves and shoots of trees
Lived: about 152-145 million years ago in the Late Jurassic Period in western North America
brachiosaurus
About half of the height of Brachiosaurus is due to the neck. This, with its long front legs and tall shoulders, meant that it could reach high up into the trees to feed. Even its front feet contributed to its high reach – the fingers are arranged long and pillar-like, and arranged vertically in the hand. Despite its fame, it is one of the rarest of the sauropods of the Morrison Formation.
A large, powerful heart pumped blood all the way up Brachiosaurus’ neck to its small brain. Some scientists believed it may have even have had several hearts to pump the blood around its massive body. Strong muscles along the neck bones helped to hold up its head. Unlike most dinosaurs, Brachiosaurus’ front legs were longer than its back legs. These helped to support the weight of its long neck.
Brachiosaurus browsed among the treetops that were out of reach for other herbivores. Using its long neck, it could pluck the highest leaves, in the same way that giraffes feed today. Brachiosaurus had strong jaws with teeth shaped rather like sharp-edged spoons for nipping off shoots and twigs. The position of the neck – whether it was vertical or horizontal – is an ongoing debate among scientists.
Brachiosaurus’ legs ended in short, thick toes. Underneath the bones of each foot was a pad which cushioned the legs against the jarring shock of its weight. Brachiosaurus held its legs straight underneath its body. This helped to support its enormous body weight. Elephants also hold their legs very straight beneath their bodies.
Brachiosaurus needed to eat an enormous amount to supply enough energy for its huge body to grow and move about. An elephant eats about 150kg of food a day. Brachiosaurus may have eaten as much as 1500kg of food a day – ten times as much as the average elephant. It probably travelled in herds and roamed over large areas of land each day to find fresh trees.
Because Brachiosaurus was so heavy, scientists once thought that it lived in lakes and rivers, where the water would support its massive weight. They believed that its legs would sink deep into the ground as it walked on land. Its nostrils were on the top of its head so it could probably keep its head above the water to breathe. In the water, Brachiosaurus would be safe from attack by fierce carnivores.
Nowadays however, scientists believe that Brachiosaurus lived only on land. The pressure of the water would have crushed its ribs, squashing its lungs. We now know, too, thats its legs were strong enough to carry the weight of its body as it lumbered through forests, along rivers and around lakes.

Brachiosaurus (“armhagedis”), was één van de grootste Mesozoïsche landdieren die ooit geleefd heeft. Hij werd minstens 25 meter lang en woog meer dan dan vijftig ton. Hij leefde tijdens het Boven – Jura- Noordamerika, Afrika en azië die toen nog van één landmassa deel uitmaakten: Pangaea.

Brachiosaurus had een kleine kop in verhouding tot zijn lichaam, een typisch kenmerk van de groep waartoe hij behoorde: de sauropoda. De Brachiosauridae (Brachiosaurus zelf en enkele verwante soorten), hadden zéér lange voorpoten; samen met de lange nek konden ze wellicht zo hun hoofd tot wel dertien meter (Sauroposeidon proteles) hoogte brengen om boomtakken van naalden te ontdoen. Met hun tanden, konden ze niet kauwen; het voedsel werd misschien door maagstenen (gastrolieten) verpulverd.

Anders dan veel andere sauropoden, hadden de brachiosauriërs een vrij korte staart. Het is niet helemaal duidelijk hoe ze erin slaagden het bloed tot zo’n hoogte op te pompen. Sommigen suggereren daarom dat de nek vrijwel horizontaal gehouden werd. Omdat de onderste nekwervels niet goed bekend zijn, kan dat niet duidelijk bewezen of weerlegd worden. Er was in ieder geval geen sprake van een abrupte overgang: de achterste nekwervels waren niet wigvormig en maakten slechts een geleidelijke bocht naar boven mogelijk. Sommige afbeeldingen van skeletten lijken dat iets anders aan te geven maar dat komt doordat ze correct tonen dat de overlapping met de volgende nekwervel kantelt als de nek gekromd wordt. Indien de nekwervels van Brachiosaurusgevormd zijn als die van de meeste andere sauropoden, was zeker een hoek van ongeveer 45 graden met de al oplopende ruggewervels mogelijk wat de nek zo’n zestig graden omhoog deed steken.

Er worden tegenwoordig drie soorten erkend:

  • B.altithorax: de Amerikaanse vorm.
  • B.atalaiensis: de vorm uit Noord-Afrika en Portugal, tegenwoordig ook wel toegeschreven aan een apart genus: Lusotitan.
  • B.brancai: de vorm uit Tanzania.

Brachiosaurus brancai is door Gregory S. Paul in 1988 een subgenus toegekend: Giraffatitan. George Olshevsky stelde in 1991 voor dit als een apart genus te beschouwen. Dit voorstel werd de eerste tijd algemeen veronachtzaamd, maar vindt de laatste jaren steeds meer instemming.

 60 ton lichter dan eerder geschat

− 06/06/12,− Bron: afp
© thinkstock.

Een van de zwaarste dinosaurussen ooit op aarde kan heel wat lichter zijn geweest. In plaats van de gedachte 80.000 kilo woog de Brachiosaurus volgens een nieuwe berekening ‘slechts’ 23.000 kilo, een verschil van zo’n 60 ton dat overeenkomt met zes bussen.

“Onze bevindingen duiden erop dat alle dinosaurussen te zwaar zijn ingeschat”, zegt onderzoeker Bill Sellers van de Universiteit van Manchester. Voor de meeste soorten is het verschil echter niet zo groot als voor de Brachiosaurus.

Berekeningen
Het team biologen maakte nieuwe berekeningen aan de hand van de lichaamsmassa van dieren als de bizon, olifant, kameel, ijsbeer en neushoorn. “Zoogdieren zijn maar enigszins verwant met de dino’s, maar de manier waarop ze staan en bewegen is vrijwel hetzelfde, zodat we denken dat ze best als model kunnen dienen.”

Belang
In het verleden werd de massa van de uitgestorven zwaargewichten op nogal artistieke manier geschat. “We zochten een objectievere methode”, zei Sellers. “Het gewicht van een dier is het belangrijkste gegeven voor een bioloog. Alle andere eigenschappen worden daarvan afgeleid.”

Voorbeeld
De zogeheten Berlijnse Brachiosaurus, ofwel de Giraffatitan brancai, was gekozen als rekenvoorbeeld omdat hiervan een van de compleetste fossielen bestaat. Het dier leefde volgens wetenschappers circa 200 tot 145 miljoen jaar geleden. Het was van neus tot staart ongeveer 25 meter lang.

 

brachyceratops

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brachylophosaurus

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brachytrachelopan

Brontomerus_Utahraptor

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Bugenasaura

bugenasaura

buitreraptor

Buitreraptor

buitre

The discovery of a bird-like dinosaur in South America has paleontologists rethinking when, where and how one group of raptors evolved.
The rooster-sized dinosaur is called Buitreraptor (bwee-tree-rap-tor) gonzalezorum. It has a long head and long tail and wing-like forelimbs. Its serrated teeth, like steak knives, suggest it was a carnivore.

Buitreraptor is related to Velociraptor, the presumed cunning killer made famous by Hollywood. Both belong to a class of birdlike dinosaurs that ran swiftly on two legs and are called dromaeosaurs.
The new find suggests such raptors go back much further in time that previously thought.

New timeline
Until recently, dromaeosaurs had been found only in Asia and North America and only in the Cretaceous period, which ran from 145 million to 65 million years ago. Evidence that they existed in the Southern Hemisphere has been mounting.
Today’s announcement of a well preserved fossil represents the first definitive evidence that dromaeosaurs roamed South America. Here’s why that’s important:
About 200 million years ago, Earth had just one giant land mass called Pangea. Toward the end of the Jurassic period, it split in two. Laurasia eventually became North America, Asia and Europe. The other chunk, Gondwana, developed into the continents of the Southern Hemisphere and India.
Since dromaeosaurs had only been found in places that used to be part of Laurasia, scientists figured the beasts evolved into being after Pangea split.
But the Buitreraptor fossil in South America, which dates back 90 million years and closely resembles fossils from the North, means one of two things:

Either dromaeosaurs existed when Pangea was intact;
or the newfound Buitreraptor and its northern look-alikes evolved separately yet with remarkably similar results.
Odds being against such striking parallel evolution, paleontologists speculate that dromaeosaurs likely originated more than 180 million years ago, before Pangaea broke apart. The newly discovered fossil also shows that the creatures developed slightly different characteristics after they split up.
“Buitreraptor is one of those special fossils that tells a bigger story about the Earth’s history and the timing of evolutionary events,” said Peter Makovicky, curator of dinosaurs at The Field Museum. “It not only provides definitive evidence for a more global distribution and a longer history for dromaeosaurs than was previously known, but also suggests that dromaeosaurs on northern and southern continents took different evolutionary routes after the landmasses they occupied drifted apart.”

Odd duck 
The Buitreraptor fossil was found in northwestern Patagonia about 700 miles southwest of Buenos Aires.
The field research was led by Argentine paleontologist Sebastián Apesteguía. The discovery is detailed in the Oct. 13 issue of the journal Nature.
Buitreraptor is an odd duck among dinosaurs. Its peculiarly long snout may have evolved to hunt snakes, mammals, and lizards that burrowed into the ground. Fossils of such critters found near Buitreraptor suggest that scenario.
The large, hollow wishbone of the dinosaur, along with its wing-like forelimbs and bird-like pelvis, add more evidence to the theory that birds evolved from dinosaurs, the scientists said.
An analysis of Buitreraptor also reveals it to be very similar to Rhonavis, which had been thought to be a primitive bird. The researchers now believe the two constitute a separate branch of the dromaeosaur family tree.

Buitreraptor gonzalezorum

Parmi les dinosaures carnivores, les dromaeosauridés étaient de petits prédateurs très agressifs. Par leur intelligence, ils surpassaient la plupart des autres théropodes. La découverte d’un nouveau dinosaure de cette famille, Buitreraptor gonzalezorum, en Argentine, remet totalement en question leur arbre généalogique.

En effet, jusqu’à présent tous les fossiles de dromaeosauridés, comprenant entre autre Deinonychus et Velociraptor, ont été découverts en Asie et en Amérique du Nord.

Les paléontologues, de ce fait, pensaient que ces dinosaures étaient apparus au Jurassique, bien que les fossiles retrouvés datent du Crétacé.
Pourquoi le Jurassique ?

Dérive des continents au Jurassique

La Pangée, ce supercontinent qui s’est formé au cours du Permien, et a existé durant tout le Trias, a commencé à se dissoudre au Jurassique.

La Pangée éclata lorsque l’océan Atlantique s’ouvrit.
Cette ouverture s’effectua entre l’Afrique et l’Amérique du Sud d’une part, et l’Amérique du Nord et l’Europe d’autre part.
Cette fissure sépara l’Amérique du Nord et l’Amérique du Sud.

A la fin du Jurassique, il y a 160 millions d’années environ, la mer Téthys s’étendit presque autour du monde entier.
Elle séparait l’Asie du continent du Gondwana, et forma donc une séparation entre l’Amérique du Nord et l’Amérique du Sud, en constituant une sorte de précurseur de la mer Caraïbe.

Continents au Jurassique

Au Crétacé, la Pangée se divisa en deux continents :

  • La Laurasie au nord
  • Le Gondwana au sud

 Apparition des Dromaeosauridés remise en question

La découverte de Buitreraptor gonzalezorum remet donc en cause l’évolution de cette famille. Avant cette découverte, l’apparition des dromaeosauridés était estimée à la fin du Jurassique. On pensait que cette famille s’était particulièrement développée dans l’Hémisphère nord au Crétacé inférieur et moyen.

Buitreraptor gonzalezorum

Buitreraptor gonzalezorum. By Dinoguy2. Licence

Leur distribution, Amérique du Nord et Asie, était donc directement reliée à la position qu’occupaient les continents au moment de leur apparition.

Or, la découverte d’un dromaeosaure en Amérique du Sud prouve que leur apparition est bien antérieure.
Ce dinosaure a évolué avant la séparation de la Pangée. Son origine pourrait remonter à 180 millions d’années.

 Buitreraptor gonzalezorum

Le squelette découvert est très complet. Il est daté du Crétacé supérieur. Sebastiàn Apesteguìa et ses collègues en ont donné une première description dans la revue Nature.

Buitreraptor gonzalezorum

Buitreraptor gonzalezorum. The Field Museum. By opacity

« Ce dinosaure avait la taille d’un très gros coq, avec une tête très allongée, une très longue queue et de petites dents espacées. Il possède les caractéristiques d’un coureur (longues pattes arrière) et d’un prédateur (bras allongés).
Ce spécimen vivait il y a environ 90 millions d’années. «

V.Battaglia (14.10.2005)

 Les Dromaeosaures

skull  Bunostegos

Klik hier om een link te hebben waarmee u dit artikel later terug kunt lezen.DINOSAURICON B

http://en.wikipedia.org/wiki/Bonapartenykus
http://www.sciencedirect.com/science/article/pii/S0195667111001923
http://blogs.smithsonianmag.com/dinosaur/2011/12/eggs-and-enigmatic-dinosaurs/http://www.zie.nl/video/algemeen/Argentijnen-vinden-botten-en-eieren-van-dino/m1fzacaftdbk
http://www.zie.nl/video/algemeen/Wetenschappers%20ontdekken-nieuwe-dinosoort/m1fzf9lfojlp

Bijlagen:
B beeldmateriaal.docx (8 MB)
B.doc (2.4 MB)
DINO B.doc (1.6 MB)   

Over tsjok45
Gepensioneerd . Improviserend jazzmuzikant . Instant composer. Jamsession fanaat Gentenaar in hart en nieren

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