V rozlehl\u00fdch prostor\u00e1ch geologick\u00e9ho souvrstv\u00ed Kaiparowits, ukryt\u00e9ho v n\u00e1rodn\u00edm parku Grand Staircase-Escalante, se \u010dtvrt stolet\u00ed ukr\u00fdvala pozoruhodn\u00e1 zkamen\u011blina. Tato zkamen\u011blina, nyn\u00ed zn\u00e1m\u00e1 jako Mirarce eatoni, pat\u0159ila pt\u00e1koje\u0161t\u011brovi, starobyl\u00e9mu rodu pt\u00e1k\u016f, kte\u0159\u00ed koexistovali s dinosaury v obdob\u00ed k\u0159\u00eddy.<\/p>\n\n
Jessie Atterholt, uzn\u00e1van\u00e1 paleontolo\u017eka, pe\u010dliv\u011b zkoumala tento mimo\u0159\u00e1dn\u011b dob\u0159e zachoval\u00fd exempl\u00e1\u0159. Fos\u00edlie odhalila tvora p\u016fsobiv\u00e9 velikosti, srovnateln\u00e9ho s krocanem divok\u00fdm, a vykazovala p\u0159ibli\u017en\u011b 30 % jeho kostry, v\u010detn\u011b t\u00e9m\u011b\u0159 v\u0161ech \u010d\u00e1st\u00ed t\u011bla krom\u011b lebky.<\/p>\n\n
Podrobn\u00e1 anal\u00fdza anatomie Mirarce eatoni odhalila soubor pokro\u010dil\u00fdch adaptac\u00ed pro let, kter\u00e9 jej odli\u0161ovaly od jeho d\u0159\u00edv\u011bj\u0161\u00edch p\u0159\u00edbuzn\u00fdch pt\u00e1koje\u0161t\u011br\u016f. Nejv\u00fdrazn\u011bji m\u011bl hluboce k\u00fdlovitou hrudn\u00ed kost, kter\u00e1 poskytovala dostatek m\u00edst pro \u00fapon siln\u00fdch letov\u00fdch sval\u016f, podobn\u011b jako u modern\u00edch pt\u00e1k\u016f.<\/p>\n\n
Krom\u011b toho jeho vidlicov\u00e1 kost, neboli furcula, vykazovala v\u00fdrazn\u00fd tvar p\u00edsmene V, rys, kter\u00fd zvy\u0161oval s\u00edlu m\u00e1v\u00e1n\u00ed k\u0159\u00eddly. P\u0159\u00edtomnost \u201ebrkov\u00fdch hrbolk\u016f\u201c na p\u0159edlokt\u00ed nazna\u010dovala m\u00edsta \u00faponu pro letky, co\u017e pt\u00e1kovi umo\u017e\u0148ovalo vzn\u00e1\u0161et se vzduchem s v\u011bt\u0161\u00ed \u00fa\u010dinnost\u00ed a na v\u011bt\u0161\u00ed vzd\u00e1lenosti.<\/p>\n\n
Pt\u00e1koje\u0161t\u011b\u0159i, navzdory sv\u00fdm pokro\u010dil\u00fdm adaptac\u00edm pro let, z\u00e1hadn\u011b vymizeli b\u011bhem hromadn\u00e9ho vym\u00edr\u00e1n\u00ed, kter\u00e9 vyhubilo dinosaury a mnoho dal\u0161\u00edch druh\u016f p\u0159ed 65 miliony lety. Tato z\u00e1hada tr\u00e1p\u00ed paleontology po cel\u00e1 desetilet\u00ed.<\/p>\n\n
Jedna z p\u0159evl\u00e1daj\u00edc\u00edch teori\u00ed nazna\u010duje, \u017ee pt\u00e1koje\u0161t\u011b\u0159i mohli b\u00fdt siln\u011b z\u00e1visl\u00ed na lesn\u00edch biotopech, kde h\u0159adovali a hn\u00edzdili. Kataklyzmick\u00e1 ud\u00e1lost, jako nap\u0159\u00edklad dopad asteroidu nebo sope\u010dn\u00e1 erupce, mohla zdecimovat lesy po cel\u00e9m sv\u011bt\u011b, \u010d\u00edm\u017e by se zlikvidovalo jejich prim\u00e1rn\u00ed prost\u0159ed\u00ed a vedlo k jejich vyhynut\u00ed.<\/p>\n\n
Zaj\u00edmav\u00e9 je, \u017ee pokro\u010dil\u00e9 adaptace pro let, kter\u00e9 vykazuje Mirarce eatoni, zrcadl\u00ed ty, kter\u00e9 se vyskytuj\u00ed u modern\u00edch pt\u00e1k\u016f. Tento objev vyvol\u00e1v\u00e1 ot\u00e1zky o evolu\u010dn\u00edch cest\u00e1ch, kter\u00e9 vedly k p\u0159e\u017eit\u00ed modern\u00edch pt\u00e1k\u016f, zat\u00edmco jejich prot\u011bj\u0161ky pt\u00e1koje\u0161t\u011b\u0159i zahynuli.<\/p>\n\n
Paleontologov\u00e9 spekuluj\u00ed, \u017ee p\u0159edkov\u00e9 modern\u00edch pt\u00e1k\u016f mohli m\u00edt ur\u010dit\u00e9 v\u00fdhody, kter\u00e9 jim umo\u017enily p\u0159e\u010dkat hromadn\u00e9 vym\u00edr\u00e1n\u00ed. Mezi tyto v\u00fdhody mohly pat\u0159it adaptace pro hn\u00edzd\u011bn\u00ed na zemi, \u0161ir\u0161\u00ed spektrum potravn\u00edch zdroj\u016f nebo lep\u0161\u00ed letov\u00e9 schopnosti, kter\u00e9 jim umo\u017enily uniknout zni\u010duj\u00edc\u00edm \u00fa\u010dink\u016fm ztr\u00e1ty prost\u0159ed\u00ed.<\/p>\n\n
Objev Mirarce eatoni a jeho pokro\u010dil\u00fdch adaptac\u00ed pro let prohloubil z\u00e1hadu obklopuj\u00edc\u00ed vyhynut\u00ed pt\u00e1koje\u0161t\u011br\u016f. C\u00edlem prob\u00edhaj\u00edc\u00edho v\u00fdzkumu je odhalit d\u016fvody jejich vymizen\u00ed a vrhnout sv\u011btlo na evolu\u010dn\u00ed historii pta\u010d\u00edho letu.<\/p>","protected":false},"excerpt":{"rendered":"
Pt\u00e1koje\u0161t\u011b\u0159i: Pokro\u010dil\u00ed letci z \u00e9ry dinosaur\u016f Objev a popis V rozlehl\u00fdch prostor\u00e1ch geologick\u00e9ho souvrstv\u00ed Kaiparowits, ukryt\u00e9ho v n\u00e1rodn\u00edm parku Grand Staircase-Escalante, se \u010dtvrt stolet\u00ed ukr\u00fdvala pozoruhodn\u00e1 zkamen\u011blina. Tato zkamen\u011blina, nyn\u00ed…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[138],"tags":[6346,6345,6344,1381,561,6347,137],"class_list":["post-3281","post","type-post","status-publish","format-standard","hentry","category-paleontology","tag-flight-adaptations","tag-dinosaur-era","tag-enantiornithines","tag-bird-evolution","tag-mass-extinction","tag-mirarce-eatoni","tag-paleontology"],"_links":{"self":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/3281","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/comments?post=3281"}],"version-history":[{"count":1,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/3281\/revisions"}],"predecessor-version":[{"id":3282,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/3281\/revisions\/3282"}],"wp:attachment":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/media?parent=3281"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/categories?post=3281"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/tags?post=3281"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}