Dinosaures à plumes

Spyrex · 04-03-2016 12:28:41

On ne sait même pas s'il avait des plumes, en fait.

Ulfric Sombrage · 04-03-2016 16:16:51

"Reconstructions usually depict it with feathers, as Chatterjee originally interpreted structures on the arm to be quill knobs, the attachment point for flight feathers found in some modern birds and non-avian dinosaurs. However, re-evaluation of the fossil material by subsequent authors such as Lawrence Witmer have been inconclusive regarding whether or not these structures are actual quill knobs."

Allosaure80 · 04-03-2016 17:21:50

Je croyais que Protoavis était une chimère ?

Ulfric Sombrage · 04-03-2016 17:24:02

Chatterjee was convinced that some of these crushed bones belonged to two individuals – one old, one young – of the same species. However, only a few parts were found, primarily a skull and some limb bones which moreover do not well agree in their proportions respective to each other, and this has led many to believe that the Protoavis fossil is chimaeric, made up of more than one organism: the pieces of skull appear like those of a coelurosaur, while the femur and ankle bone catalogued under TTU P-9200 and TTU P-9201 respectively suggest affinities to non-tetanuran theropods[23] and at least some vertebrae are most similar to those of Megalancosaurus, an avicephalan diapsid:[24] However, those supposed similarities between the cervicals of Protoavis and drepanosaurids were the same similarities that Feduccia and Wild (1993) used to argue for an affinity between Archaeopteryx and drepanosaurids.[25]

"Everywhere one turns; the very fossils ascribed thereto challenge the validity of Protoavis. The most parsimonious conclusion to be inferred from these data is that Chatterjee's contentious find is nothing more than a chimera, a morass of long-dead archosaurs."[26]

If it really is a single animal and not a chimera, Protoavis would raise interesting questions about when birds began to diverge from the dinosaurs, but until better evidence is produced, the animal's status currently remains uncertain. Furthermore, paleobiogeography suggests that true birds did not colonize the Americas until the Cretaceous; the most primitive lineages of unequivocal birds found to date are all Eurasian.[21] Certainly, the fossils are most parsimoniously attributed to primitive dinosaurian and other reptiles as outlined above. However, coelurosaurs and ceratosaurs are in any case not too distantly related to the ancestors of birds and in some aspects of the skeleton not unlike them, explaining how their fossils could be mistaken as avian. Palaeontologist Zhonghe Zhou stated:

"[Protoavis] has neither been widely accepted nor seriously considered as a Triassic bird ... [Witmer], who has examined the material and is one of the few workers to have seriously considered Chatterjee’s proposal, argued that the avian status of P. texensis is probably not as clear as generally portrayed by Chatterjee, and further recommended minimization of the role that Protoavis plays in the discussion of avian ancestry."[27]

Welman has argued that the quadrate of Protoavis displays synapomorphies of Theropoda.[28] Paul has demonstrated the drepanosaur affinities of the cervical vertebrae. Gauthier & Rowe, and Dingus & Rowe have argued convincingly for identifying the hind limb of Protoavis as belonging to a ceratosaur. Feduccia has argued that Protoavis represents an arboreal "thecodont".[29] In a study of early ornithischian dinosaurs, Sterling Nesbitt and others determined some of the partial remains of Protoavis to be a non-tetanuran theropod.[30] The entire skull and neck are considered to be most likely from a drepanosaurid because the skull and neck are too big compared to the dorsal vertebrate of Protoavis

Ulfric Sombrage · 19-03-2016 16:51:01

nicolasollivier a écrit :

Bah pas par rapport à cet article, je pense qu'on peut oublier largement les T. rex adultes couverts de plumes.

C'est mieux qu'on continue ici.

Allosaure80 · 14-04-2016 22:20:11

http://calgary.ctvnews.ca/alberta-resea … -1.2859173

Un nouveau Oviraptorosauria(précisément un Caenagnathidae)a était décrit, son nom Apatoraptor, il vivait a l'actuel Alberta au Canada. smile

Ulfric Sombrage · 15-04-2016 15:10:36

velociraptor_portrait___jp3_by_tnilab_ekneb121-d9z2hy6.jpg

Ulfric Sombrage · 26-04-2016 22:17:17

Spyrex · 27-04-2016 06:04:44

Austroraptor ?

Ulfric Sombrage · 27-04-2016 06:17:33

Unenlagia comahuensis.

Spyrex · 27-04-2016 11:32:57

Easy, Carcharodontosaurus.

Monsieur ADN · 13-06-2016 12:14:07

nicolasollivier · 13-06-2016 12:55:48

C'est bizarre, j'ai l'impression d'un certain vide en regardant cette vidéo.

Allosaure80 · 28-06-2016 17:06:51

BigG47 · 28-06-2016 17:11:56

Joli !

Spyrex · 03-07-2016 08:35:30

Une aile de Dinosaure retrouvée dans de l'ambre, vieille de 99 millions d'années.

Ulfric Sombrage · 02-09-2016 15:42:45

http://dinogoss.blogspot.fr/2013/09/you … cales.html

Monsieur ADN · 08-10-2016 12:05:03

Du terrifiant lézard à la grosse poule: l’image des dinosaures a bien changé

http://www.francetvinfo.fr/animaux/vide … 28185.html

Beuhaaaaaaaa.... mad

Et dans la vidéo : les lézards tueurs.
Beuhaaarg....

EDIT : une expo sur les dinos à plume à Rennes si ça intéresse les bretons du forum.
http://culturebox.francetvinfo.fr/expos … nes-246649

Dernière modification par Monsieur ADN (08-10-2016 15:11:53)

Monsieur ADN · 28-10-2016 15:35:25

Une récente étude démontre que les Avimimus disposaient d'un comportement grégaire.
http://www.sci-news.com/paleontology/av … 04307.html

Monsieur ADN · 14-11-2016 16:14:50

Je vous présente Tongtianlong limosus, nouvel Oviraptoridae du Crétacé Supérieur.
http://www.sci-news.com/paleontology/to … 04355.html
http://www.parismatch.com/Actu/Sciences … te-1115699

EDIT :
Certains dinosaures à plumes pourraient avoir été iridescents.
http://www.seeker.com/some-dinosaur-era … 59927.html

Dernière modification par Monsieur ADN (17-11-2016 12:50:13)

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#358 08-10-2016 12:05:03

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Du terrifiant lézard à la grosse poule: l’image des dinosaures a bien changé

#359 28-10-2016 15:35:25

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