{"id":208355,"date":"2026-09-09T14:57:17","date_gmt":"2026-09-09T14:57:17","guid":{"rendered":"https:\/\/www.europesays.com\/cz\/208355\/"},"modified":"2026-09-09T14:57:17","modified_gmt":"2026-09-09T14:57:17","slug":"cerstve-vylihnuty-tyrannosaurus-rex-byl-velky-jen-jako-dnesni-krkavec","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/cz\/208355\/","title":{"rendered":"\u010cerstv\u011b vyl\u00edhnut\u00fd Tyrannosaurus rex byl velk\u00fd jen jako dne\u0161n\u00ed krkavec"},"content":{"rendered":"

O pravd\u011bpodobn\u00e9m vzez\u0159en\u00ed a\u00a0velikosti \u201enovorozen\u011bte\u201c druhu Tyrannosaurus rex jsem ji\u017e pojednal v\u00a0d\u0159\u00edve. Dosud v\u0161ak byly prakticky v\u0161echny podobn\u00e9 \u00fadaje zalo\u017eeny pouze na hypot\u00e9z\u00e1ch, domn\u011bnk\u00e1ch a\u00a0nejist\u00fdch odhadech<\/a>. Na\u0161t\u011bst\u00ed v\u0161ak p\u0159ekvapiv\u00fdch objev\u016f i\u00a0zaj\u00edmav\u00fdch v\u00fdzkum\u016f stabiln\u011b p\u0159ib\u00fdv\u00e1 a\u00a0nov\u00e1 odborn\u00e1 pr\u00e1ce, publikovan\u00e1 ned\u00e1vno v\u00a0odborn\u00e9m\u00a0periodiku Biology, p\u0159in\u00e1\u0161\u00ed prvn\u00ed pon\u011bkud ov\u011b\u0159en\u011bj\u0161\u00ed \u00fadaje, zalo\u017een\u00e9 na skute\u010dn\u00fdch datech.[1] Hlavn\u00edm autorem t\u00e9to pr\u00e1ce je m\u00edrn\u011b kontroverzn\u00ed, ale z\u00a0hlediska sv\u00e9 odbornosti v\u00fdborn\u00fd paleontolog Nicholas R. Longrich, kter\u00fd se sv\u00fdm t\u00fdmem poprv\u00e9 p\u0159in\u00e1\u0161\u00ed nejenom odhady velikosti \u010derstv\u011b vyl\u00edhnut\u00e9ho tyranosaura, ale tak\u00e9 odhady mno\u017estv\u00ed vaj\u00ed\u010dek, kter\u00e9 tyranosau\u0159\u00ed samice sn\u00e1\u0161ely, odhady hmotnosti cel\u00e9 sn\u016f\u0161ky v\u00a0z\u00e1vislosti na t\u011blesn\u00fdch rozm\u011brech tyranosau\u0159\u00ed matky, p\u0159edstavu o\u00a0reproduk\u010dn\u00edch strategi\u00edch dinosaur\u016f v\u00a0obecn\u00e9 rovin\u011b a\u00a0nap\u0159\u00edklad tak\u00e9 \u00favahy o\u00a0podob\u011b a\u00a0ekologii samotn\u00fdch ml\u00e1\u010fat nebo o\u00a0rodi\u010dovsk\u00fdch strategi\u00edch tyranosaurid\u016f. Tyto zaj\u00edmav\u00e9 \u00favahy byly a\u017e do ned\u00e1vn\u00e9 doby zcela hypotetick\u00e9, chyb\u011bly toti\u017e jak\u00e9koliv fosiln\u00ed podklady, na kter\u00fdch by se dalo stav\u011bt.[2] <\/p>\n

A\u010dkoliv jsou toti\u017e fosilie velk\u00fdch exempl\u00e1\u0159\u016f tyranosauridn\u00edch teropod\u016f relativn\u011b hojn\u00e9, zcela jin\u00e1 je situace v\u00a0p\u0159\u00edpad\u011b jejich hn\u00edzd, vajec a\u00a0mal\u00fdch ml\u00e1\u010fat zhruba do v\u011bku 2\u00a0let. P\u0159esto se ji\u017e poda\u0159ilo n\u011bkter\u00e9 fosilie velmi mal\u00fdch jedinc\u016f tyranosauridn\u00edch teropod\u016f objevit, a\u00a0Longrich\u016fv t\u00fdm se zam\u011b\u0159il na jejich detailn\u00ed v\u00fdzkum a\u00a0interpretaci. Za pou\u017eit\u00ed synchrotronov\u00e9 mikrotomografie a\u00a0dal\u0161\u00edch pokro\u010dil\u00fdch metod provedli pe\u010dliv\u00fd histologick\u00fd rozbor mikroskopick\u00e9 stavby drobn\u00fdch fosili\u00ed. Zkoumali tak\u00e9 chemick\u00e9 slo\u017een\u00ed a\u00a0vnit\u0159n\u00ed strukturu t\u011bchto k\u016fstek a\u00a0zub\u016f n\u011bkolika jedinc\u016f druh\u016f Tyrannosaurus rex, Gorgosaurus libratus a\u00a0(z\u0159ejm\u011b) Nanotyrannus sp<\/a>. Tyto fosilie byly objeveny p\u0159edev\u0161\u00edm v\u00a0souvrstv\u00edch Hell Creek na \u00fazem\u00ed americk\u00e9ho st\u00e1tu Ji\u017en\u00ed Dakota a\u00a0v souvrstv\u00ed Frenchman na \u00fazem\u00ed kanadsk\u00e9 provincie Saskatchewan.[3] V\u011bdci pak porovn\u00e1vali z\u00edskan\u00e9 informace o\u00a0vzorci r\u016fstu tyranosaurid\u016f s\u00a0podobn\u00fdmi \u00fadaji od jin\u00fdch teropod\u016f i\u00a0dal\u0161\u00edch dinosaur\u016f a\u00a0pokusili se tak vytvo\u0159it prvn\u00ed hrub\u00fd r\u00e1mec na\u0161ich v\u011bdomost\u00ed o\u00a0celkov\u00e9m vzez\u0159en\u00ed, ekologii a\u00a0ontogenezi mal\u00fdch tyranosaurid\u016f, kte\u0159\u00ed v\u00a0dosp\u011blosti p\u0159edstavovali dominantn\u00ed pred\u00e1tory sv\u00fdch ekosyst\u00e9m\u016f.<\/p>\n

D\u016fle\u017eitou roli m\u011blo tak\u00e9 porovn\u00e1v\u00e1n\u00ed a\u00a0dopl\u0148ov\u00e1n\u00ed chyb\u011bj\u00edc\u00edch informac\u00ed ze studia sou\u010dasn\u00fdch v\u00fdvojov\u00fdch p\u0159\u00edbuzn\u00fdch tyranosaurid\u016f, tedy pt\u00e1k\u016f a\u00a0krokod\u00fdl\u016f<\/a>. Auto\u0159i studie p\u0159edpokl\u00e1dali, \u017ee z\u00a0hlediska reproduk\u010dn\u00edch strategi\u00ed se tyranosauridi nach\u00e1zeli zhruba uprost\u0159ed mezi \u201eprimitivn\u011bj\u0161\u00ed\u201c podobou rodi\u010dovsk\u00e9 p\u00e9\u010de krokod\u00fdl\u016f (u kter\u00fdch pozorujeme jist\u00fd stupe\u0148 ochrany vaj\u00ed\u010dek i\u00a0ml\u00e1\u010fat) a\u00a0mezi vysp\u011blej\u0161\u00ed podobou pta\u010d\u00ed rodi\u010dovsk\u00e9 p\u00e9\u010de, kter\u00e1 je obvykle velmi intenzivn\u00ed a\u00a0odpov\u00edd\u00e1 pta\u010d\u00ed strategii vysok\u00e9 energetick\u00e9 a\u00a0\u010dasov\u00e9 investice do rychle rostouc\u00edho potomstva.[4] Jak se ji\u017e d\u0159\u00edve p\u0159edpokl\u00e1dalo, mal\u00e1 ml\u00e1\u010fata tyranosaurid\u016f vypadala zcela jinak ne\u017e dosp\u011bl\u00ed jedinci, a\u00a0to nejen z\u00a0hlediska celkov\u00e9 velikosti, ale tak\u00e9 tvaru t\u011bla a\u00a0potravn\u00ed strategie. Drobn\u00fd fragment metatarz\u00e1ln\u00ed k\u016fstky objeven\u00fd v\u00a0sedimentech geologick\u00e9ho souvrstv\u00ed Frenchman a\u00a0p\u0159isuzovan\u00fd druhu Tyrannosaurus rex (fosiln\u00ed exempl\u00e1\u0159 se sb\u00edrkov\u00fdm ozna\u010den\u00edm RSKM P2416.82) pat\u0159il velmi mal\u00e9mu ml\u00e1d\u011bti, kter\u00e9 podle histologick\u00e9ho rozboru kosti nebylo star\u0161\u00ed ne\u017e 1\u00a0rok.<\/p>\n

Foto: Dornicke; Wikimedia Commons (voln\u00e9 d\u00edlo).<\/p>\n

Hypotetick\u00fd model tyranosau\u0159\u00edho embrya z\u00a0expozice Brazilsk\u00e9ho n\u00e1rodn\u00edho muzea ve m\u011bst\u011b Rio de Janeiro.<\/p>\n

Odhadovan\u00e1 hmotnost jej\u00edho p\u016fvodce \u010dinila pouze 2,5\u00a0kilogramu (p\u0159esn\u011bji 2459\u00a0gram\u016f) a\u00a0celkov\u00e1 d\u00e9lka t\u011bla asi 75\u00a0cm. V\u00a0dob\u011b vyl\u00edhnut\u00ed z\u00a0vaj\u00ed\u010dka v\u0161ak bylo ml\u00e1d\u011b je\u0161t\u011b men\u0161\u00ed, podle odhad\u016f autor\u016f pr\u00e1ce mohlo v\u00e1\u017eit zhruba 1,7\u00a0kg. U\u00a0ml\u00e1d\u011bte druhu Gorgosaurus libratus (fosiln\u00ed exempl\u00e1\u0159 TMP 1981.16.475) vy\u0161la v\u011bdc\u016fm podobn\u00e1 velikost (hmotnost 2389\u00a0gram\u016f a\u00a0d\u00e9lka kolem 70\u00a0centimetr\u016f), v\u00a0dob\u011b vyl\u00edhnut\u00ed pak mohlo m\u00edt p\u0159ibli\u017en\u011b hmotnost 1,3\u00a0kg (1325\u00a0gram\u016f) a\u00a0d\u00e9lku 50\u00a0cm. To vcelku dob\u0159e odpov\u00edd\u00e1 velikostn\u00edmu rozd\u00edlu mezi druhem T. rex a\u00a0G. libratus, a\u010dkoliv v\u00fdrazn\u011b v\u011bt\u0161\u00ed dosp\u011bl\u00e9 hmotnosti (~8\u00a0tun oproti ~3\u00a0tun\u00e1m) dosahovali tyranosau\u0159i a\u017e v\u00a0pr\u016fb\u011bhu pozd\u011bj\u0161\u00edho r\u016fstu.[5] \u010cerstv\u011b vyl\u00edhnut\u00fd tyranosaurus nebo gorgosaurus byli tedy tvory o\u00a0velikosti statn\u011bj\u0161\u00edho krkavce velik\u00e9ho (a jejich hmotnost byla zhruba dvojn\u00e1sobn\u011b a\u017e trojn\u00e1sobn\u011b ni\u017e\u0161\u00ed, ne\u017e p\u0159edpokl\u00e1dal nap\u0159\u00edklad Peter Larson). L\u00edhli se z\u00a0vaj\u00ed\u010dek dlouh\u00fdch kolem 40\u00a0cm, kter\u00fdch tyranosau\u0159\u00ed samice kladly a\u017e n\u011bkolik des\u00edtek najednou. V\u00a0z\u00e1vislosti na vyu\u017eit\u00ed \u00fadaj\u016f od krokod\u00fdl\u016f nebo pt\u00e1k\u016f mohla cel\u00e1 sn\u016f\u0161ka v\u00e1\u017eit asi 54\u00a0a\u017e 60\u00a0kg u\u00a0tyranosau\u0159\u00ed samice B-rex (MOR 1125) s\u00a0odhadovanou hmotnost\u00ed kolem 6100\u00a0kg a\u00a0d\u00e1le pak 71\u00a0a\u017e 79\u00a0kg u\u00a0podstatn\u011b mohutn\u011bj\u0161\u00edho exempl\u00e1\u0159e Sue (FMNH PR2081) s\u00a0odhadovanou hmotnost\u00ed kolem 9500\u00a0kg<\/a>.[6]<\/p>\n

V\u00a0p\u0159\u00edpad\u011b druh\u00e9ho exempl\u00e1\u0159e v\u0161ak nezn\u00e1me pohlav\u00ed a\u00a0podle Longriche mohly b\u00fdt i\u00a0nejv\u011bt\u0161\u00ed samice stejn\u011b jako v\u00a0p\u0159\u00edpad\u011b mnoha pta\u010d\u00edch druh\u016f o\u00a0trochu men\u0161\u00ed ne\u017e samci (co\u017e by sni\u017eovalo i\u00a0odhadovanou celkovou hmotnost sn\u016f\u0161ky). Z\u00a0t\u011bchto \u00fadaj\u016f bylo d\u00e1le odhadnuto mno\u017estv\u00ed nakladen\u00fdch vajec, a\u00a0to ve vysok\u00e9m po\u010dtu 21\u00a0a\u017e 32.\u00a0To je vy\u0161\u0161\u00ed \u010d\u00edslo, ne\u017e v\u00a0p\u0159\u00edpad\u011b v\u011bt\u0161iny pt\u00e1k\u016f, ale naopak ni\u017e\u0161\u00ed ne\u017e u\u00a0mnoha krokod\u00fdl\u016f a\u00a0\u017eelv. Je ale tak\u00e9 mo\u017en\u00e9, \u017ee ve sn\u016f\u0161ce bylo je\u0161t\u011b podstatn\u011b v\u00edce vajec (teoreticky i\u00a050\u00a0a\u017e 100), a\u00a0to o\u00a0hmotnosti mezi 100\u00a0a\u00a0300\u00a0kg, co\u017e by nicm\u00e9n\u011b p\u0159edstavovalo st\u00e1le jen zhruba 1-3\u00a0% u\u00a0velk\u00e9 samice tyranosaura v\u00e1\u017e\u00edc\u00ed 9,5\u00a0a\u017e 10\u00a0tun<\/a>. V\u00a0ka\u017ed\u00e9m p\u0159\u00edpad\u011b byl po\u010det nakladen\u00fdch vaj\u00ed\u010dek pom\u011brn\u011b velk\u00fd, co\u017e odpov\u00edd\u00e1 tzv. r-strategii, typick\u00e9 pro mnoh\u00e9 sou\u010dasn\u00e9 plazy (nap\u0159\u00edklad \u017eelvy a\u00a0\u0161upinat\u00e9), kdy vysokou m\u00edru reprodukce dopl\u0148uje mal\u00e1 a\u017e \u017e\u00e1dn\u00e1 m\u00edra rodi\u010dovsk\u00e9 p\u00e9\u010de. Ml\u00e1\u010fata tyranosaur\u016f byla tak\u00e9 v\u00a0pom\u011bru ke sv\u00e9\u00a0dosp\u011bl\u00e9 velikosti v\u011bt\u0161\u00ed ne\u017e v\u00fdrazn\u00e1 v\u011bt\u0161ina dal\u0161\u00edch plaz\u016f, ale naopak men\u0161\u00ed ne\u017e u\u00a0vysp\u011blej\u0161\u00edch z\u00e1stupc\u016f kladu Eumaniraptora (v\u010detn\u011b pt\u00e1k\u016f), co\u017e dokl\u00e1d\u00e1, \u017ee jejich reproduk\u010dn\u00ed strategie byla celkov\u011b vysp\u011blej\u0161\u00ed ne\u017e u\u00a0v\u00fdvojov\u011b primitivn\u011bj\u0161\u00edch diapsid\u016f, ale m\u00e9n\u011b vysp\u011bl\u00e1 ne\u017e u\u00a0pt\u00e1k\u016f.[7] <\/p>\n

Tyranosau\u0159i tedy sice mohli jistou rodi\u010dovskou p\u00e9\u010di potomstvu ve vaj\u00ed\u010dk\u00e1ch i\u00a0kr\u00e1tce po vyl\u00edhnut\u00ed poskytovat, celkov\u011b ale v\u00a0tomto sm\u011bru sp\u00ed\u0161e investovali minimum \u010dasu a\u00a0energie. Pokud se p\u0159ece jen n\u011bjak\u00e1 investice do potomstva objevila, pak t\u00e9m\u011b\u0159 s\u00a0jistotou jen v\u00a0uniparent\u00e1ln\u00ed podob\u011b (staral se pouze jeden z\u00a0rodi\u010d\u016f), podobn\u011b jako je tomu u\u00a0krokod\u00fdl\u016f a\u00a0v\u00fdvojov\u011b primitivn\u00edch pt\u00e1k\u016f. Tomu odpov\u00edd\u00e1 dal\u0161\u00ed zji\u0161t\u011bn\u00ed, \u017ee mal\u00ed tyranosau\u0159i byli vysoce prekoci\u00e1ln\u00ed (\u201enekrmiv\u00ed\u201c a\u00a0od po\u010d\u00e1tku prakticky samostatn\u00ed) a\u00a0nesetrv\u00e1vali v\u00a0hn\u00edzd\u011b. Dob\u0159e vyvinut\u00e9 kloubn\u00ed plo\u0161ky na kostech i\u00a0opot\u0159ebovan\u00e1 sklovina zub\u016f dokl\u00e1daj\u00ed, \u017ee dok\u00e1zali tak\u0159ka okam\u017eit\u011b opou\u0161t\u011bt m\u00edsto narozen\u00ed a\u00a0aktivn\u011b si hledat potravu v\u00a0okol\u00ed.[8] Op\u011bt se zde jasn\u011b ukazuje, \u017ee reproduk\u010dn\u00ed strategie tyranosaurid\u016f m\u011bla jakousi p\u0159echodnou podobu mezi primitivn\u011bj\u0161\u00ed r-strategi\u00ed v\u011bt\u0161iny plaz\u016f a\u00a0vysp\u011blej\u0161\u00ed K-strategi\u00ed pt\u00e1k\u016f. Pr\u00e1v\u011b u\u00a0teropodn\u00edch dinosaur\u016f je mo\u017en\u00e9 v\u00a0pr\u016fb\u011bhu druhohorn\u00ed \u00e9ry pozorovat postupn\u00fd p\u0159echod od prvn\u00ed strategie ke druh\u00e9 a\u00a0velc\u00ed a\u017e ob\u0159\u00ed tyranosauridi pat\u0159ili v\u00a0tomto sm\u011bru pravd\u011bpodobn\u011b k\u00a0vysp\u011blej\u0161\u00edm z\u00e1stupc\u016fm velk\u00fdch nepta\u010d\u00edch dinosaur\u016f<\/a>.[9]<\/p>\n

Short Summary in English:<\/p>\n

New study demonstrate, that non-avian dinosaurs were intermediate between more primitive diapsid reptiles and modern birds in their anatomy, and reproductive strategies. Reproductive strategies of tyrannosaurid theropods remain poorly understood because fossils of young tyrannosaurids and their eggs are rare. A\u00a0fossil metatarsal bone of very young T. rex and other tyrannosaurs help us understand the reproductive strategies of these predators. Tyrannosaurid theropods had relatively small hatchlings compared to modern Aves, as they laid large numbers of eggs and provided relatively little care for their ~1.5\u00a0kg hatchlings. Dinosaur reproductive strategies were intermediate between those of basal diapsids, with quite limited parental investment, and very intensive investment seen in majority of modern birds.<\/p>\n","protected":false},"excerpt":{"rendered":"O pravd\u011bpodobn\u00e9m vzez\u0159en\u00ed a\u00a0velikosti \u201enovorozen\u011bte\u201c druhu Tyrannosaurus rex jsem ji\u017e pojednal v\u00a0d\u0159\u00edve. Dosud v\u0161ak byly prakticky v\u0161echny podobn\u00e9…\n","protected":false},"author":2,"featured_media":208356,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[13],"tags":[24561,36205,32375,489,37988,39179,6297,487,74,73,78,75,38232,77,76,589,4006],"class_list":["post-208355","post","type-post","status-publish","format-standard","has-post-thumbnail","category-veda-a-technika","tag-dinosaurus","tag-druhohory","tag-embryo","tag-fosilie","tag-jursky-park","tag-jursky-svet","tag-lihnuti","tag-paleontologie","tag-science","tag-science-technology","tag-technika","tag-technology","tag-tyrannosaurus-rex","tag-veda","tag-veda-a-technika","tag-vejce","tag-zkamenelina"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@cz\/117241672516312790","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/posts\/208355","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/comments?post=208355"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/posts\/208355\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/media\/208356"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/media?parent=208355"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/categories?post=208355"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/cz\/wp-json\/wp\/v2\/tags?post=208355"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}