Re: [2012] Brèves de l'actualité des dinosauresPosté par Webmaster
On est loin des 70 cm d'envergure de libellules au Carbonifère, mais ça fait déjà de la bonne puce...
Posté par AgressiveHumanParasa
Brrr... J'aimerais pas avoir ces horreurs sur moi où même sur un animal de compagnie.
Posté par Lolo
Longrich, N.R. & Field, D.J. (2012) Torosaurus Is Not Triceratops: Ontogeny in Chasmosaurine Ceratopsids as a Case Study in Dinosaur Taxonomy. PLoS ONE 7(2)
Résumé: In horned dinosaurs, taxonomy is complicated by the fact that the cranial ornament that distinguishes species changes with age. Based on this observation, it has been proposed that the genera Triceratops and Torosaurus are in fact synonymous, with specimens identified as Torosaurus representing the adult form of Triceratops. The hypothesis of synonymy makes three testable predictions: 1) the species in question should have similar geographic and stratigraphic distributions, 2) specimens assigned to Torosaurus should be more mature than those assigned to Triceratops, and 3) intermediates should exist that combine features of Triceratops and Torosaurus. The first condition appears to be met, but it remains unclear whether the other predictions are borne out by the fossil evidence.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0032623
Résumé: In horned dinosaurs, taxonomy is complicated by the fact that the cranial ornament that distinguishes species changes with age. Based on this observation, it has been proposed that the genera Triceratops and Torosaurus are in fact synonymous, with specimens identified as Torosaurus representing the adult form of Triceratops. The hypothesis of synonymy makes three testable predictions: 1) the species in question should have similar geographic and stratigraphic distributions, 2) specimens assigned to Torosaurus should be more mature than those assigned to Triceratops, and 3) intermediates should exist that combine features of Triceratops and Torosaurus. The first condition appears to be met, but it remains unclear whether the other predictions are borne out by the fossil evidence.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0032623
Posté par Trex
Donc finalement torosaurus n'est plus un vieux trice, je m'en doutais un peu.
Posté par Stalker
Je vote toujours pour un dimorphisme sexuel...
Posté par Fablespinosaurus
On avait toujours pas trouver des puces? Bon, au moins c'est fait.
Si il étaient si diversifiées que ça, leurs origines remontent-ils au Trias? Dans ce cas là, la présence de poiles chez les dinosaures datant de cette époque est surement affirmée (sans compter les mammifères)?
Posté par Lolo
Stephen L. Brusatte, Thomas D. Carr, and Mark A. Norell (2012) The Osteology of Alioramus, A Gracile and Long-Snouted Tyrannosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Mongolia. Bulletin of the American Museum of Natural History:1-197.
Résumé: The Late Cretaceous tyrannosaurid theropod Alioramus has long been one of the most puzzling large carnivorous dinosaur taxa, largely because for several decades it has been represented only by a single, fragmentary specimen that seems to represent a long-snouted and gracile individual but is difficult to interpret. The discovery of a substantially complete skeleton of Alioramus at the Tsaagan Khuushu locality in the Maastrichtian Nemegt Formation of Mongolia, recovered during the 2001 American Museum–Mongolian Academy of Sciences expedition and described as a new species (Alioramus altai) in 2009, definitively shows that this mysterious taxon is a distinct form of longirostrine tyrannosaurid that lived alongside the larger and more robust Tarbosaurus. Here we describe and figure this remarkably preserved skeleton in detail. We provide exhaustive descriptions and photographs of individual bones, and make extensive comparisons with other tyrannosauroids. This monographic description provides further evidence that Alioramus is an unusual long-snouted, gracile, and slender-limbed taxon with an unpredecented degree of cranial ornamentation among tyrannosaurids and an extremely pneumatized skeleton.
Anatomical comparisons indicate that the long skull of Alioramus is an autapomorphic feature that is proportionally longer (relative to femur length) than in any other known tyrannosaurid specimen, including juveniles, and that Alioramus is morphologically distinctive relative to similarly sized individuals of the contemporary and sympatric Tarbosaurus. The holotype specimen of A. altai belongs to a young individual, and many differences between it and the other known specimen of Alioramus (the holotype of A. remotus) may represent ontogenetic variation. The unusual longirostrine skull of Alioramus was largely produced by lengthening of the snout bones (maxilla, nasal, dentary, lacrimal, jugal), rather than the orbiotemporal bones (frontal, postorbital, squamosal, quadratojugal). The long snout, gracile skull bones, comparatively small attachment sites for jaw muscles, and lack of interlocking sutures and a robust orbital brow would have precluded the holotype individual from employing the characteristic “puncture-pull” feeding style of large-bodied adult tyrannosaurids, in which the muscular jaws, thick teeth, and interlocking sutures enabled individuals to bite with enough force to fracture bone. Whether adult Alioramus could utilize “puncture-pull” feeding awaits discovery of mature individuals of the genus. The coexistence of the long-snouted Alioramus and robust and deep-snouted Tarbosaurus, which are found together at the Tsaagan Khuushu locality, demonstrate that multiple large tyrannosaurids were able to live in sympatry, likely because of niche partitioning due to differences in craniofacial morphology and functional behavior.
Il n'est pas encore en ligne; voici le lien à surveiller:
http://digitallibrary.amnh.org/dspace/handle/2246/7/browse
Résumé: The Late Cretaceous tyrannosaurid theropod Alioramus has long been one of the most puzzling large carnivorous dinosaur taxa, largely because for several decades it has been represented only by a single, fragmentary specimen that seems to represent a long-snouted and gracile individual but is difficult to interpret. The discovery of a substantially complete skeleton of Alioramus at the Tsaagan Khuushu locality in the Maastrichtian Nemegt Formation of Mongolia, recovered during the 2001 American Museum–Mongolian Academy of Sciences expedition and described as a new species (Alioramus altai) in 2009, definitively shows that this mysterious taxon is a distinct form of longirostrine tyrannosaurid that lived alongside the larger and more robust Tarbosaurus. Here we describe and figure this remarkably preserved skeleton in detail. We provide exhaustive descriptions and photographs of individual bones, and make extensive comparisons with other tyrannosauroids. This monographic description provides further evidence that Alioramus is an unusual long-snouted, gracile, and slender-limbed taxon with an unpredecented degree of cranial ornamentation among tyrannosaurids and an extremely pneumatized skeleton.
Anatomical comparisons indicate that the long skull of Alioramus is an autapomorphic feature that is proportionally longer (relative to femur length) than in any other known tyrannosaurid specimen, including juveniles, and that Alioramus is morphologically distinctive relative to similarly sized individuals of the contemporary and sympatric Tarbosaurus. The holotype specimen of A. altai belongs to a young individual, and many differences between it and the other known specimen of Alioramus (the holotype of A. remotus) may represent ontogenetic variation. The unusual longirostrine skull of Alioramus was largely produced by lengthening of the snout bones (maxilla, nasal, dentary, lacrimal, jugal), rather than the orbiotemporal bones (frontal, postorbital, squamosal, quadratojugal). The long snout, gracile skull bones, comparatively small attachment sites for jaw muscles, and lack of interlocking sutures and a robust orbital brow would have precluded the holotype individual from employing the characteristic “puncture-pull” feeding style of large-bodied adult tyrannosaurids, in which the muscular jaws, thick teeth, and interlocking sutures enabled individuals to bite with enough force to fracture bone. Whether adult Alioramus could utilize “puncture-pull” feeding awaits discovery of mature individuals of the genus. The coexistence of the long-snouted Alioramus and robust and deep-snouted Tarbosaurus, which are found together at the Tsaagan Khuushu locality, demonstrate that multiple large tyrannosaurids were able to live in sympatry, likely because of niche partitioning due to differences in craniofacial morphology and functional behavior.
Il n'est pas encore en ligne; voici le lien à surveiller:
http://digitallibrary.amnh.org/dspace/handle/2246/7/browse
Posté par AgressiveHumanParasa
Et dire qu'on parlais de ce théropode il y a peu de temps.
Posté par Lolo
C'est en ligne, le bazar fait 85 Mo
Posté par Croc en stock
Xu, X., K. Wang, K. Zhang, Q. Ma, L. Xing, C. Sullivan, D. Hu, S. Cheng, and S. Wang. 2012. A gigantic feathered dinosaur from the Lower Cretaceous of China. Nature 484: 92-95.
Yutyrannus huali, un tyrannosauroïde de 9 m ayant des "plumes" !
Yutyrannus huali, un tyrannosauroïde de 9 m ayant des "plumes" !
Posté par Lolo
Bel engin !
Posté par Leolios
Ah sa oui ! 
Posté par Stalker
C'est un tyrannosauroide du genre guanlong ou du genre T-rex
Posté par Lolo
Posté par Leolios
Maintenant,je m'imagine facilement un gorgosaurus ou un daspletosaurus couver de plumes !
Posté par Stalker
C'est génial!
Posté par Theropod
Je ne sais pas si Crock a l'article mais sinon il est chez moi.
Dites donc, 9m, 1 tonne 4 et à plumes, je me demande si on pense encore que T.rex perdait ses plumes au cours de sa croissance.
Dites donc, 9m, 1 tonne 4 et à plumes, je me demande si on pense encore que T.rex perdait ses plumes au cours de sa croissance.
Posté par Matt
Y-a t-il des chances pour qu'on puisse découvrir des fossiles de Tyrannosaurus ou de Tarbosaurus à plumes maintenant ?
Yutyrannus était entièrement couvert de plumes ? Le doute m'envahit , il est apparemment signalé que les plumes étaient localisées davantage vers les membres postérieurs et inférieurs de ce théropode .
Yutyrannus était entièrement couvert de plumes ? Le doute m'envahit , il est apparemment signalé que les plumes étaient localisées davantage vers les membres postérieurs et inférieurs de ce théropode .
Posté par Gigy
Un mixte des deux on a des empruntes de peau pour Tarbosaurus à Bugin Tsav en Mongolie.
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