{"id":272997,"date":"2025-07-25T14:49:11","date_gmt":"2025-07-25T14:49:11","guid":{"rendered":"https:\/\/www.europesays.com\/fr\/272997\/"},"modified":"2025-07-25T14:49:11","modified_gmt":"2025-07-25T14:49:11","slug":"grenoble-un-fossile-vieux-de-247-millions-dannees-au-coeur-dune-decouverte-paleontologique-majeure","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/fr\/272997\/","title":{"rendered":"Grenoble. Un fossile vieux de 247\u00a0millions d\u2019ann\u00e9es au c\u0153ur d\u2019une d\u00e9couverte pal\u00e9ontologique majeure"},"content":{"rendered":"

Un cr\u00e2ne minuscule, vieux de 247\u00a0millions d\u2019ann\u00e9es, vient bouleverser notre compr\u00e9hension de l\u2019\u00e9volution. Et c\u2019est \u00e0 Grenoble, au Synchrotron europ\u00e9en (ESRF)<\/a> , que les chercheurs ont lev\u00e9 le voile sur ce fossile \u00e9tonnant\u00a0: Mirasaura grauvogeli ou \u00ab\u00a0\u00e9tonnant reptile de Grauvogel\u00a0\u00bb, en hommage au collectionneur alsacien qui l\u2019a d\u00e9nich\u00e9 dans les ann\u00e9es 1930.<\/p>\n

Le fossile dormait depuis au Mus\u00e9e d\u2019histoire naturelle de Stuttgart, avant d\u2019\u00eatre scann\u00e9 au rayon X sur la ligne BM18 de l\u2019ESRF. R\u00e9sultat\u00a0: une cr\u00eate dorsale unique, dont la structure rappelle celle des plumes, mais dont l\u2019origine \u00e9volutive est tout autre.<\/p>\n

\u00ab\u00a0Quelque chose d\u2019exceptionnel\u00a0\u00bb<\/p>\n

\u00ab\u00a0Au d\u00e9but, la cr\u00eate a laiss\u00e9 les scientifiques perplexes\u00a0\u00bb, raconte Stephan Spiekman, pal\u00e9ontologue au mus\u00e9e de Stuttgart et premier auteur de l\u2019\u00e9tude parue dans Nature. Le scan 3D du cr\u00e2ne a r\u00e9v\u00e9l\u00e9 une morphologie singuli\u00e8re\u00a0: museau effil\u00e9, grandes orbites orient\u00e9es vers l\u2019avant, dents sur le palais et un cr\u00e2ne bomb\u00e9, typique d\u2019un tr\u00e8s jeune individu. Des caract\u00e9ristiques communes aux animaux arboricoles.<\/p>\n

Mais c\u2019est cette fameuse cr\u00eate, compos\u00e9e d\u2019appendices denses et complexes, qui intrigue. Ni poils, ni v\u00e9ritables plumes, ces excroissances pourraient avoir servi \u00e0 la communication entre individus. Une alternative \u00e9volutive aux plumes, d\u00e9velopp\u00e9e bien avant les dinosaures \u00e0 plumes connus depuis les ann\u00e9es 1990. \u00ab\u00a0Mirasaura fournit la premi\u00e8re preuve directe que de telles structures ont \u00e9merg\u00e9 tr\u00e8s t\u00f4t dans l\u2019histoire \u00e9volutive des reptiles\u00a0\u00bb, s\u2019\u00e9merveille Stephan Spiekman.<\/p>\n

Une d\u00e9couverte rendue possible par l \u2019extr\u00eame finesse des faisceaux de lumi\u00e8re synchrotron<\/a> , capables de d\u00e9voiler la structure interne d\u2019un fossile de moins de 0,5\u00a0mm de large. \u00ab\u00a0Sans l\u2019ESRF, il aurait \u00e9t\u00e9 impossible de r\u00e9aliser la reconstruction du cr\u00e2ne\u00a0\u00bb, explique le chercheur. Kathleen Dollman, scientifique \u00e0 l\u2019ESRF et coautrice de l\u2019\u00e9tude, ajoute\u00a0: \u00ab\u00a0D\u00e8s les premi\u00e8res images, on a compris qu\u2019on tenait quelque chose d\u2019exceptionnel.\u00a0\u00bb<\/p>\n","protected":false},"excerpt":{"rendered":"Un cr\u00e2ne minuscule, vieux de 247\u00a0millions d\u2019ann\u00e9es, vient bouleverser notre compr\u00e9hension de l\u2019\u00e9volution. Et c\u2019est \u00e0 Grenoble, au…\n","protected":false},"author":2,"featured_media":272998,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9566],"tags":[1111,11,1867,2430,112,1777,674,107,1011,27,2731,2732,1757,108,12,25,767],"class_list":{"0":"post-272997","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-grenoble","8":"tag-actu","9":"tag-actualites","10":"tag-animaux","11":"tag-auvergne-rhone-alpes","12":"tag-edition-grenoble-agglomeration","13":"tag-eu","14":"tag-europe","15":"tag-fil-info","16":"tag-fr","17":"tag-france","18":"tag-grenoble","19":"tag-grenoble-bassin","20":"tag-insolite","21":"tag-isere","22":"tag-news","23":"tag-republique-francaise","24":"tag-science-et-technologie"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@fr\/114914431208343145","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/posts\/272997","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/comments?post=272997"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/posts\/272997\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/media\/272998"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/media?parent=272997"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/categories?post=272997"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/fr\/wp-json\/wp\/v2\/tags?post=272997"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}