Une piste de dinosaures un peu spéciale avait été découverte en 1940 le long de la rivière Paluxy, au Texas, par le paléontologue R.Bird. Les traces s'étendaient sur 45 m de long et étaient datées de 110 millions d'années, elles appartenaient à un Théropode et un Sauropode. La position des traces laissaient penser à une scène de chasse entre les 2 dinosaures.
Le paléontologue avait alors immortalisé les traces par une série de 17 photos, et heureusement car depuis, une partie des traces a été excavée et envoyée dans divers musées dans le monde, et l'autre partie a "disparue". Une équipe de scientifiques du Royal Veterinary College a réussi à réaliser une reconstitution 3D de la scène à partir des photographies, leur rapport est présenté dans PLOS ONE.
Quand le paléontologue avait analysé la piste il y a 75 ans, il avait remarqué que certaines traces du Théropode chevauchaient celles du Sauropode, laissant penser que le Théropode était passé juste derrière. Les Théropodes sont les ancêtres de nos oiseaux modernes, ils étaient carnivores et parmi eux on trouvait les fameux Tyrannosaures et Vélociraptors. Les Sauropodes quand à eux étaient des herbivores à long cou comme les Brachiosaures et les Apatosaures.
Si une partie des traces a été excavée et envoyée dans différents musées et instituts, l'autre partie a "disparue", il ne reste donc que les photos pour se souvenir du site.
Des scientifiques ont scanné les photos et les ont assemblées par ordinateur pour obtenir une image cohérente du site. A partir de techniques de photogrammétrie, ils ont reconstitué un modèle 3D du site. Les ombres des empreintes sur les photos ont permis d'estimer la profondeur des traces, malgré des problèmes de netteté sur certaines photos. A partir de ces informations, ils peuvent imprimer une réplique du site avec des imprimantes 3D. Cette technique ouvre la porte à d'autres études dont les objets originaux ont disparus mais dont ils reste des photos.
Paleontologist
Roland T. Bird first excavated fossilized tracks along the Paluxy River
in Texas in 1940. The tracks belong to a theropod and sauropod that
lived 110 million years ago, and appear to be the remains of an ancient
chase. Bird documented the scene 45-meter-long (147 ft) scene with 17
photographs, and then the actual fossils were sectioned off and sent
around the world. A new paper by Peter Falkingham of the Royal
Veterinary College and his colleagues have now made 3D reconstructions
of the scene based off of those photographs. The full report has been
published in PLOS ONE.
When Bird first analyzed the scene nearly 75 years ago, he noted that some of the theropod tracks overlapped the sauropod tracks, which made it look like the theropod came soon after. Theropods are a primarily carnivorous clade of dinosaurs that are the ancestors of modern birds and some famous genera in the theropod suborder include Tyrannosaurus and Velociraptor. Herbivorous sauropods have long necks and long tails, and include Brachiosaurus and Apatosaurus.
Though some sections of the site were transported to educational institutions, others have been irrevocably lost over the years, with only Bird’s analysis and photographs to represent the entire site.
Falkingham’s study scanned the photographs and combined them in order to have a cohesive image of the entire scene. Through photogrammetry, the researchers were able to construct a 3D computer image of the original site. Shading on the tracks gave information about the depth of the tracks, though not all of the photographs yielded the same clarity. With that information, scientists can now make replicas of the chase scene using a 3D printer. This technique could open the door for other studies where the physical object is lost, but clear photographs remain.
Paul Barrett of London’s Natural History Museum told BBC News that Falkingham’s work was part of a “neat study.” "It has allowed the [team] to recover important data previously thought to be irrevocably lost," he continued. "These dinosaur track sites are of major historical importance, and being able to retrieve this level of information 70 years after they were broken up and dispersed is a nice outcome."
Read more at http://www.iflscience.com/plants-and-animals/110-million-year-old-dinosaur-chase-scene-digitally-reconstructed#T1zEFhlHslD3eJh8.9
When Bird first analyzed the scene nearly 75 years ago, he noted that some of the theropod tracks overlapped the sauropod tracks, which made it look like the theropod came soon after. Theropods are a primarily carnivorous clade of dinosaurs that are the ancestors of modern birds and some famous genera in the theropod suborder include Tyrannosaurus and Velociraptor. Herbivorous sauropods have long necks and long tails, and include Brachiosaurus and Apatosaurus.
Though some sections of the site were transported to educational institutions, others have been irrevocably lost over the years, with only Bird’s analysis and photographs to represent the entire site.
Falkingham’s study scanned the photographs and combined them in order to have a cohesive image of the entire scene. Through photogrammetry, the researchers were able to construct a 3D computer image of the original site. Shading on the tracks gave information about the depth of the tracks, though not all of the photographs yielded the same clarity. With that information, scientists can now make replicas of the chase scene using a 3D printer. This technique could open the door for other studies where the physical object is lost, but clear photographs remain.
Paul Barrett of London’s Natural History Museum told BBC News that Falkingham’s work was part of a “neat study.” "It has allowed the [team] to recover important data previously thought to be irrevocably lost," he continued. "These dinosaur track sites are of major historical importance, and being able to retrieve this level of information 70 years after they were broken up and dispersed is a nice outcome."
Read more at http://www.iflscience.com/plants-and-animals/110-million-year-old-dinosaur-chase-scene-digitally-reconstructed#T1zEFhlHslD3eJh8.9
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