[2012] Brèves paléontologiques générales
Discussion:
60 008
114
Dernière réponse
60 008
114
Dernière réponse
Posté par Webmaster
Nouvelle année, nouvelle discussion pour toutes les actualités paléontologiques, à l'exclusion de celles sur les dinosaures.
Posté par Naldo
New Ophthalmosaurid Ichthyosaurs from the European Lower Cretaceous Demonstrate Extensive Ichthyosaur Survival across the Jurassic–Cretaceous Boundary
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0029234
Un nouvel ichthyosaure ophthalmosauride du Crétacé moyen d'Angleterre, très proche d'Ophthalmosaurus. C'est le plus récent ophthalmosauridé, et les auteurs suggèrent donc que les ichthyosaures n'ont été que peu affectés (voire pas du tout) par le passage Jurassique/Crétacé, là où on pensait qu'ils avaient subi un évènement d'extinction.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0029234
Un nouvel ichthyosaure ophthalmosauride du Crétacé moyen d'Angleterre, très proche d'Ophthalmosaurus. C'est le plus récent ophthalmosauridé, et les auteurs suggèrent donc que les ichthyosaures n'ont été que peu affectés (voire pas du tout) par le passage Jurassique/Crétacé, là où on pensait qu'ils avaient subi un évènement d'extinction.
Posté par AgressiveHumanParasa
Intérressant. Les ichtyosaures ont donc passé la barre de Jurassique-crétacé.
Posté par Naldo
Oh oui on le savait depuis longtemps. J'ai peut être pas assez clair.
Par contre on pensait qu'ils avaient morflé.
Par contre on pensait qu'ils avaient morflé.
Posté par Leolios
Il aurait pas disparue vers 90 Ma
Posté par Croc en stock
Limite Cénomanien-Turonien 
Posté par Charlie
Ce qui est intéressant dans ce que j'ai lu de l'affaire, c'est qu'à priori, il faudrait aussi revoir les fossiles existants d'ichtyosaures du crétacé qui sont tous plus ou moins mis dans le genre Platyptérygius et qui seraient en fait plus variés qu'il n'y parait (Platyptérygius devenant un peu un genre "valise").
Pour ceux qui veulent une version un chouia plus vulgarisé, par l'auteur de l'article : http://blogs.scientificamerican.com/tetrapod-zoology/2012/01/03/cretaceous-ichthyosaur-revolution-part-i/
Pour ceux qui veulent une version un chouia plus vulgarisé, par l'auteur de l'article : http://blogs.scientificamerican.com/tetrapod-zoology/2012/01/03/cretaceous-ichthyosaur-revolution-part-i/
Posté par Lolo
JUNCHANG LÜ, DAVID M. UNWIN, BO ZHAO, CHUNLING GAO & CAIZHI SHEN (2012) A new rhamphorhynchid (Pterosauria: Rhamphorhynchidae) from the Middle/Upper Jurassic of Qinglong, Hebei Province, China. Zootaxa 3158: 1–19
Résumé: A heavily compressed, but nearly complete fossil skeleton recovered from the Middle/Upper Jurassic Tiaojishan Formation of Mutoudeng, Qinglong County, Hebei Province, China, represents a new genus and species of long-tailed pterosaur, Qinglongopterus guoi gen. et sp. nov. The holotype and only known specimen has an estimated forelimb length of 0.18 m. The new taxon is distinguished by a relatively short skull, a remarkably short pteroid with a distinctive knob-like distal expansion, and a prepubis with a relatively slender distal process. Phylogenetic analysis demonstrates that Qinglongopterus is a member of Rhamphorhynchidae, exhibiting many of the unique character states found in members of this clade. Qinglongopterus is strikingly similar to Rhamphorhynchus and more closely related to this taxon than to any other rhamphorhynchine, this pairing is supported by morphometric data and several synapomorphies (short, broad nasal process of the maxilla; forelimb length more than four times that of the hind limb; wing-phalanx one more than twice the length of the tibia). Qinglongopterus demonstrates that the highly derived skeletal morphology of Rhamphorhynchus, known only from the latest Jurassic (Tithonian) of Europe, had already appeared by the start of the Late Jurassic. This hints at evolutionary stasis in Rhamphorhynchinae, a phenomenon seemingly also present in two other clades of basal pterosaurs, Anurognathidae and Scaphognathinae, and contrasting sharply with basal monofenestratans which appear to have under gone extensive evolutionary change during the same interval.
Je veux bien l'article merci !
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Edité le 12/01/2012 à 16:29 par lolo
Résumé: A heavily compressed, but nearly complete fossil skeleton recovered from the Middle/Upper Jurassic Tiaojishan Formation of Mutoudeng, Qinglong County, Hebei Province, China, represents a new genus and species of long-tailed pterosaur, Qinglongopterus guoi gen. et sp. nov. The holotype and only known specimen has an estimated forelimb length of 0.18 m. The new taxon is distinguished by a relatively short skull, a remarkably short pteroid with a distinctive knob-like distal expansion, and a prepubis with a relatively slender distal process. Phylogenetic analysis demonstrates that Qinglongopterus is a member of Rhamphorhynchidae, exhibiting many of the unique character states found in members of this clade. Qinglongopterus is strikingly similar to Rhamphorhynchus and more closely related to this taxon than to any other rhamphorhynchine, this pairing is supported by morphometric data and several synapomorphies (short, broad nasal process of the maxilla; forelimb length more than four times that of the hind limb; wing-phalanx one more than twice the length of the tibia). Qinglongopterus demonstrates that the highly derived skeletal morphology of Rhamphorhynchus, known only from the latest Jurassic (Tithonian) of Europe, had already appeared by the start of the Late Jurassic. This hints at evolutionary stasis in Rhamphorhynchinae, a phenomenon seemingly also present in two other clades of basal pterosaurs, Anurognathidae and Scaphognathinae, and contrasting sharply with basal monofenestratans which appear to have under gone extensive evolutionary change during the same interval.
Je veux bien l'article merci !
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Edité le 12/01/2012 à 16:29 par lolo
Posté par Lolo
Zoological Journal of the Linnean Society propose quelques 288 pages de Crocodiliformes, et tout ça gratos ! Nouveaux genres: Lorosuchus, Caryonosuchus, Labidiosuchus, Fruitachampsa, Pietraroiasuchus.
http://onlinelibrary.wiley.com/doi/10.1111/zoj.2011.163.issue-s1/issuetoc
http://onlinelibrary.wiley.com/doi/10.1111/zoj.2011.163.issue-s1/issuetoc
Posté par AgressiveHumanParasa
Interressant.
Posté par Naldo
A new genus of Devonian tetrapod from North-East Greenland, with new information on the lower jaw of Ichthyostega
http://onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2011.01117.x/abstract;jsessionid=A462538BB612F78DAABD04018EDC2CC0.d02t03
Un nouveau tétrapode du Dévonien, retrouvé au Groenland comme Ichthyostega et Acanthostega. Son ptit nom c'est Ymeria.
Il est caractérisé notamment par un développement important des dents coronoïdes.
http://onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2011.01117.x/abstract;jsessionid=A462538BB612F78DAABD04018EDC2CC0.d02t03
Un nouveau tétrapode du Dévonien, retrouvé au Groenland comme Ichthyostega et Acanthostega. Son ptit nom c'est Ymeria.
Il est caractérisé notamment par un développement important des dents coronoïdes.
Posté par AgressiveHumanParasa
Décidément 2012 est une bonne année en paléontologie. 
Posté par Leolios
Sa tu la dit !
Posté par Naldo
Lorna J. O'Brien, Jean-Bernard Caron. A New Stalked Filter-Feeder from the Middle Cambrian Burgess Shale, British Columbia, Canada PLoS ONE, 2012; 7 (1)
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0029233
Un nouveau taxon énigmatique de la faune de Burgess, Siphusauctum est un organisme fixé.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0029233
Un nouveau taxon énigmatique de la faune de Burgess, Siphusauctum est un organisme fixé.
Posté par Leolios
elle est jolie !
Posté par AgressiveHumanParasa
Un beau fossile dont je me demande bien à quelle famille appartient une telle créature.
Posté par Gigy
On dirait une convergence évolutive avec les crinoïdes.
Posté par Lolo
Holliday, C.M. & Gardner, N.M. (2012) A New Eusuchian Crocodyliform with Novel Cranial Integument and Its Significance for the Origin and Evolution of Crocodylia. PLoS ONE 7(1): e30471
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030471
Crocodyliforms were one of the most successful groups of Mesozoic tetrapods, radiating into terrestrial, semiaquatic and marine environments, while occupying numerous trophic niches, including carnivorous, insectivorous, herbivorous, and piscivorous species. Among these taxa were the enigmatic, poorly represented flat-headed crocodyliforms from the late Cretaceous of northern Africa. Here we report a new, giant crocodyliform from the early Late Cretaceous (Cenomanian) Kem Kem Formation of Morocco. Represented by a partial braincase, the taxon has an extremely long, flat skull with large jaw and craniocervical muscles. The skull roof is ridged and ornamented with a broad, rough boss surrounded by significant vascular impressions, likely forming an integumentary structure unique among crocodyliforms. Size estimates using endocranial volume indicate the specimen was very large. The taxon possesses robust laterosphenoids with laterally oriented capitate processes and isolated epipterygoids, features allying it with derived eusuchians. Phylogenetic analysis finds the taxon to be a derived eusuchian and sister taxon to Aegyptosuchus, a poorly understood, early Late Cretaceous taxon from the Bahariya formation. This clade forms the sister clade of crown-group Crocodylia, making these taxa the earliest eusuchian crocodyliforms known from Africa. These results shift phylogenetic and biogeographical hypotheses on the origin of modern crocodylians towards the circum-Tethyean region and provide important new data on eusuchian morphology and evolution.
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Edité le 01/02/2012 à 20:04 par lolo
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030471
Crocodyliforms were one of the most successful groups of Mesozoic tetrapods, radiating into terrestrial, semiaquatic and marine environments, while occupying numerous trophic niches, including carnivorous, insectivorous, herbivorous, and piscivorous species. Among these taxa were the enigmatic, poorly represented flat-headed crocodyliforms from the late Cretaceous of northern Africa. Here we report a new, giant crocodyliform from the early Late Cretaceous (Cenomanian) Kem Kem Formation of Morocco. Represented by a partial braincase, the taxon has an extremely long, flat skull with large jaw and craniocervical muscles. The skull roof is ridged and ornamented with a broad, rough boss surrounded by significant vascular impressions, likely forming an integumentary structure unique among crocodyliforms. Size estimates using endocranial volume indicate the specimen was very large. The taxon possesses robust laterosphenoids with laterally oriented capitate processes and isolated epipterygoids, features allying it with derived eusuchians. Phylogenetic analysis finds the taxon to be a derived eusuchian and sister taxon to Aegyptosuchus, a poorly understood, early Late Cretaceous taxon from the Bahariya formation. This clade forms the sister clade of crown-group Crocodylia, making these taxa the earliest eusuchian crocodyliforms known from Africa. These results shift phylogenetic and biogeographical hypotheses on the origin of modern crocodylians towards the circum-Tethyean region and provide important new data on eusuchian morphology and evolution.
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Edité le 01/02/2012 à 20:04 par lolo
Posté par Tyran65
Extrêmement intéressant . 
un résumé en français:
http://www.slateafrique.com/82069/ancetre-crocodiles-africains-maroc-dinosaures
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Edité le 02/02/2012 à 11:00 par Tikémi
un résumé en français:
http://www.slateafrique.com/82069/ancetre-crocodiles-africains-maroc-dinosaures
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Edité le 02/02/2012 à 11:00 par Tikémi
Posté par AgressiveHumanParasa
étonnant ce crocodile à armure .
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