Misplaced Pages

#473526

38-449: Bambiraptor is a Late Cretaceous , 72-million-year-old, bird-like dromaeosaurid theropod dinosaur described by scientists at the University of Kansas , Yale University , and the University of New Orleans . The holotype fossil is less than one meter long, although this specimen appears to be a juvenile, and it is possible that Bambiraptor is a juvenile Saurornitholestes . It

76-469: A goose 's wishbone go back to at least the Late Medieval Period . Johannes Hartlieb in 1455 recorded the divination of weather by means of a goose's wishbone, "When the goose has been eaten on St. Martin's Day or Night, the oldest and most sagacious keeps the breast-bone and allowing it to dry until the morning examines it all around, in front, behind and in the middle. Thereby they divine whether

114-434: A juvenile individual. Though the right side of the skeleton is damaged, most bones are uncompressed and well-preserved. The end of the tail is lacking. Also a paratype was assigned in 2000, FIP 002-136, consisting of thirty-four skeletal elements of at least two adult individuals found near the holotype. In 2004 an upper jaw bone was referred to the species, specimen MOR 553S-7-30-91-274. While adult specimens are known, only

152-403: A new genus: Bambiraptor feinbergi . The generic name is derived from Bambi , in reference to the young age of the specimen, and a Latin raptor , "seizer". The specific epithet honours Michael and Ann Feinberg who acquired the specimen from a fossil poacher and made it available to science. In 2000 George Olshevsky suggested the emended epithet "feinbergorum", the plural genitive , and this

190-631: A northward course towards Asia. In the Southern Hemisphere, Australia and Antarctica seem to have remained connected and began to drift away from Africa and South America. Europe was an island chain. Populating some of these islands were endemic dwarf dinosaur species. In the Late Cretaceous, the hadrosaurs , ankylosaurs , and ceratopsians experienced success in Asiamerica (Western North America and eastern Asia). Tyrannosaurs dominated

228-483: A result of hunting more agile prey items such as lizards and mammals. The Bambiraptor holotype had with 14 cm the largest brain for its size of any dinosaur yet discovered, although the brain size may be due to its age, because juvenile animals tend to have larger brain-to-body ratios compared to adults. During the conference where Bambiraptor was first introduced, the dinosaur reconstruction specialist Brian Cooley portrayed Bambiraptor as having feathers, despite

266-536: A very different dinosaurian fauna, with most predators being abelisaurids and carcharodontosaurids ; and titanosaurs being among the dominant herbivores. Spinosaurids were also present during this time. Birds became increasingly common, diversifying in a variety of enantiornithe and ornithurine forms. Early Neornithes such as Vegavis co-existed with forms as bizarre as Yungavolucris and Avisaurus . Though mostly small, marine Hesperornithes became relatively large and flightless, adapted to life in

304-403: Is a forked bone found in most birds and some species of non-avian dinosaurs, and is formed by the fusion of the two clavicles . In birds, its primary function is in the strengthening of the thoracic skeleton to withstand the rigors of flight . The furcula works as a strut between a bird's shoulders, and articulates to each of the bird's scapulae . In conjunction with the coracoid and

342-401: Is even suspected that the type specimen is a chimera, based on the fact that "there are elements of three different similarly sized lower legs included in the holotype." Because of its small size, it was named Bambiraptor feinbergi , after the popular Disney movie character (the name literally translates to "Bambi thief") and the surname of the wealthy family who bought and lent the specimen to

380-474: Is it particularly evident that a true systematic decline was ever in place, especially with the discovery of smaller pterosaur species. Several old mammal groups began to disappear, with the last eutriconodonts occurring in the Campanian of North America . In the northern hemisphere, cimolodont , multituberculates , metatherians and eutherians were the dominant mammals, with the former two groups being

418-558: The Deccan Traps , both of which have been firmly dated to the time of the extinction event. In theory, these events reduced sunlight and hindered photosynthesis , leading to a massive disruption in Earth's ecology . A much smaller number of researchers believe the extinction was more gradual, resulting from slower changes in sea level or climate . Furcula The furcula (Latin for "little fork"; pl. : furculae ) or wishbone

SECTION 10

#1732881210474

456-515: The Lamar State College in Orange, Texas has indicated that Bambiraptor may have had mutually opposable first and third fingers and a forelimb maneuverability that would allow the hand to reach its mouth. This would have given the animal the ability to "hold" food in its front limbs and place it in its mouth, in a similar manner to some modern-day small mammals. Bambiraptor had a brain size in

494-463: The air sacs . Several groups of theropod dinosaurs have also been found with furculae, including dromaeosaurids , oviraptorids , tyrannosaurids , troodontids , coelophysids and allosauroids . Seeing the occurrence in diplodocid dinosaurs of interclavicles , Tschopp and Mateus (2013) proposed that the furcula is a transformed and divided interclavicle, rather than a fused clavicle. Superstitions surrounding divination by means of

532-813: The Cretaceous Period derived from the German name Kreidezeit , and T is the abbreviation for the Tertiary Period (a historical term for the period of time now covered by the Paleogene and Neogene periods). The event marks the end of the Mesozoic Era and the beginning of the Cenozoic Era. "Tertiary" being no longer recognized as a formal time or rock unit by the International Commission on Stratigraphy ,

570-847: The K-T event is now called the Cretaceous—Paleogene (or K-Pg) extinction event by many researchers. Non- avian dinosaur fossils are found only below the Cretaceous–Paleogene boundary and became extinct immediately before or during the event. A very small number of dinosaur fossils have been found above the Cretaceous–Paleogene boundary, but they have been explained as reworked fossils , that is, fossils that have been eroded from their original locations then preserved in later sedimentary layers. Mosasaurs , plesiosaurs , pterosaurs and many species of plants and invertebrates also became extinct. Mammalian and bird clades passed through

608-605: The Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Due to plate tectonics , the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia . India maintained

646-519: The boundary with few extinctions, and evolutionary radiation from those Maastrichtian clades occurred well past the boundary. Rates of extinction and radiation varied across different clades of organisms. Many scientists hypothesize that the Cretaceous–Paleogene extinctions were caused by catastrophic events such as the massive asteroid impact that caused the Chicxulub crater , in combination with increased volcanic activity , such as that recorded in

684-583: The excavation of a skeleton that was approximately 95 percent complete. Because of its completeness Florida Paleontology Institute Director Martin Shugar compared it to the Rosetta Stone that enabled archaeologists to translate Egyptian hieroglyphics . Yale paleontologist John Ostrom , who reintroduced the theory of bird evolution from dinosaurs after his 1964 discovery of Deinonychus in Wyoming , agreed, calling

722-652: The fact that no feathers were found with the fossil itself. His decision was influenced by the fact that because Bambiraptor within a cladistic analysis was a member of a group, Paraves , that contained feathered true birds and that was the sister taxon of Oviraptorosauria , a group that also had feathered forms (e.g. Caudipteryx ), Bambiraptor most likely had feathers too due to phylogenetic bracketing. Most paleontologists support Cooley's view, and subsequent discoveries confirmed that small dromaeosaurid dinosaurs like Bambiraptor were fully covered in feathers (see Dromaeosauridae for more information). Bambiraptor

760-434: The furcula is vestigial, reduced to a thin strap of ossified ligament, seemingly purposeless. Other species have evolved the furcula in the opposite direction, so that it has increased in size and become too stiff or massive to act as a spring. In strong flyers like cranes and falcons, the arms of the furcula are large, hollow and quite rigid. In birds , the furcula also may aid in respiration by helping to pump air through

798-441: The goose-bone; and as the goose-bone predicted so did they order their two campaigns, one in summer and one in winter." The custom of two persons pulling on the bone with the one receiving the larger part making a wish developed in the early 17th century. In some family traditions, the one receiving the smaller part made the wish. At that time, the name of the bone was a merrythought . The name wishbone in reference to this custom

SECTION 20

#1732881210474

836-465: The holotype is 30-40% the size of specimen MOR 553S-7-30-91-274. Directly scaling up the holotype specimen gives a length of 2.5-3.3 m. However, this is likely a low estimate since the specimen is a maxilla with proportions like that of the holotype, and juvenile animals tend to have proportionally longer skulls. In 2010 Gregory S. Paul estimated the adult length at 1.3 metres (4.3 ft), the weight at five kilogrammes. Research done by Phil Senter of

874-646: The large predator niche in North America. They were also present in Asia, although were usually smaller and more primitive than the North American varieties. Pachycephalosaurs were also present in both North America and Asia. Dromaeosaurids shared the same geographical distribution, and are well documented in both Mongolia and Western North America. Additionally therizinosaurs (known previously as segnosaurs) appear to have been in North America and Asia. Gondwana held

912-426: The lower range of modern birds . Because of its enlarged cerebellum , which may indicate higher agility and higher intelligence than other dromaeosaurs, David A. Burnham has hypothesized that Bambiraptor feinbergi may have been arboreal. Life in the trees may have required evolutionary pressure that resulted in a larger brain. Burnham also offers an alternative hypothesis that a larger brain could be selected for as

950-636: The most common mammals in North America. In the southern hemisphere there was instead a more complex fauna of dryolestoids , gondwanatheres and other multituberculates and basal eutherians ; monotremes were presumably present, as was the last of the haramiyidans , Avashishta . Mammals, though generally small, ranged into a variety of ecological niches, from carnivores ( Deltatheroida ), to mollusc-eater ( Stagodontidae ), to herbivores (multituberculates, Schowalteria , Zhelestidae and Mesungulatidae ) to highly atypical cursorial forms ( Zalambdalestidae , Brandoniidae ). True placentals evolved only at

988-620: The new Graves Museum of Natural History in Florida . The Bambiraptor skeleton was discovered in 1995 by 14-year-old fossil hunter Wes Linster, who was looking for dinosaur bones with his parents near Glacier National Park in Montana , United States. Linster told Time magazine that he uncovered the skeleton on a tall hill and was amazed at his discovery. "I bolted down the hill to get my mom because I knew I shouldn't be messing with it", he said. The bones that Linster discovered on that hilltop led to

1026-531: The numerous teleost fishes, which in turn evolved into new advanced and modern forms ( Neoteleostei ). Ichthyosaurs and pliosaurs , on the other hand, became extinct during the Cenomanian-Turonian anoxic event . Near the end of the Cretaceous Period, flowering plants diversified. In temperate regions, familiar plants like magnolias , sassafras , roses , redwoods , and willows could be found in abundance. The Cretaceous–Paleogene extinction event

1064-407: The open sea. Though primarily represented by azhdarchids , other forms like pteranodontids , tapejarids ( Caiuajara and Bakonydraco ), nyctosaurids and uncertain forms ( Piksi , Navajodactylus ) are also present. Historically, it has been assumed that pterosaurs were in decline due to competition with birds, but it appears that neither group overlapped significantly ecologically, nor

1102-508: The scapula, it forms a unique structure called the triosseal canal, which houses a strong tendon that connects the supracoracoideus muscles to the humerus . This system is responsible for lifting the wings during the recovery stroke. As the thorax is compressed by the flight muscles during downstroke, the upper ends of the furcula spread apart, expanding by as much as 50% of its resting width, and then contracts. X-ray films of starlings in flight have shown that in addition to strengthening

1140-400: The shoulders toward the midline of the body. While the starling has a moderately large and strong furcula for a bird of its size, there are many species where the furcula is completely absent, for instance scrubbirds , some toucans and New World barbets , some owls , some parrots , turacos , and mesites . These birds are still fully capable of flying. They also have close relatives where

1178-432: The specimen a "jewel", and telling reporters that the completeness and undistorted qualities of the bones should help scientists further understand the dinosaur-bird link. The fossil first was seen as the young of Saurornitholestes and in 1997 reported as belonging to a Velociraptor sp. In 2000 it was named and described by David Burnham, Kraig Derstler , Phil Currie , Robert Bakker , Zhou Zhonge and John Ostrom as

Bambiraptor - Misplaced Pages Continue

1216-425: The thorax, the furcula acts like a spring in the pectoral girdle during flight. It expands when the wings are pulled downward and snaps back as they are raised. In this action, the furcula is able to store some of the energy generated by contraction in the breast muscles, expanding the shoulders laterally, and then releasing the energy during upstroke as the furcula snaps back to the normal position. This, in turn, draws

1254-407: The type specimen, a juvenile, has been described. This juvenile Bambiraptor has a preserved length of 90 centimetres (3.0 ft), and an estimated total length of one metre. It perhaps weighed only two kilograms (4.4 lb). It had long hindlimbs, indicating it could have been a fast runner. It also had very long arms and a well-developed wishbone . According to an SVP abstract published in 2021,

1292-433: The very end of the epoch; the same can be said for true marsupials . Instead, nearly all known eutherian and metatherian fossils belong to other groups. In the seas, mosasaurs suddenly appeared and underwent a spectacular evolutionary radiation. Modern sharks also appeared and penguin-like polycotylid plesiosaurs (3 meters long) and huge long-necked elasmosaurs (13 meters long) also diversified. These predators fed on

1330-530: The winter will be severe or mild, dry or wet, and are so confident in their prediction that they will wager their goods and chattels on its accuracy.", and of a military officer: "This valiant man, this Christian Captain drew forth out of his doublet that heretical object of superstition, the goose-bone, and showed me that after Candlemas an exceeding severe frost should occur, and could not fail." The Captain also said, "Teutonic knights in Prussia waged all their wars by

1368-537: Was a large-scale mass extinction of animal and plant species in a geologically short period of time, approximately 66  million years ago (Ma). It is widely known as the K–T extinction event and is associated with a geological signature, usually a thin band dated to that time and found in various parts of the world, known as the Cretaceous–Paleogene boundary (K–T boundary). K is the traditional abbreviation for

1406-466: Was assigned to the Dromaeosauridae in 2000, though its position within the family remains uncertain, since subsequent cladistic analyses show different results. It has been recovered as a microraptorian or a saurornitholestine , and the most recent phylogenetic analyses place it as a sister taxon or a member of Eudromaeosauria . [REDACTED] [REDACTED] Late Cretaceous During

1444-636: Was followed by some authors but such emendations are no longer allowed by the ICZN . The holotype specimen AMNH FR 30556 (previously AMNH 001 and FIP 001, sometimes wrongly referred to as AMNH FR 30554), was uncovered in layers of the Upper Two Medicine Formation dating to the late Campanian . It is currently housed at the American Museum of Natural History , New York. It consists of a partially articulated largely complete skeleton with skull of

#473526