Scientists have excavated the largest dinosaur fosil which would have been the largest terrestrial animal on our planeta.
Tim znanstvenika iz Južna Afrika, Velika Britanija i Brazil na čelu sa Sveučilištem Witwatersrand otkrili su a fosil nove vrste dinosaurus u Južnoj Africi smatra se da je srodnik brontosaurusu. Ovaj rani jurski dinosaur težio je ogromnih 26,000 funti, što je dvostruko veći od afričkog slona, a na boku je četiri metra. Nazvana je "Ledumahadi mafube" što znači "divovski udar groma u zoru" na domorodačkom jeziku sesotho regije u kojoj je otkriven.
Evolucijska tranzicija
Ledumahadi je usko povezan sa sauropod dinosaurima uključujući dobro poznate vrste Brontosaurus i Diplodocus. Bio je biljojed, imao je debele udove i bio je četveronožac, tj. hodao je na sve četiri noge u položaju sličnom modernim slonovima. U usporedbi s dugim, vitkim stupastim udovima sauropoda, Ledumahadijevi prednji udovi bili su zgrčeniji, odnosno imao je savijenije udove poput primitivnih dinosaura. Njihovi su preci hodali samo na dvije noge i sigurno su se prilagodili hodanju na sve četiri i zato su narasli kako bi podržali probavu jer su bili biljojedi.
Researchers compared fosil data from dinosaurs, reptiles etc who walked on two or four legs and they measured limb size and thickness. This is how they concluded Ledumahadi’s posture and its way of walking on all four limbs. It is understood that many other dinosaurs must have experimented walking on all four limbs which could optimally balance a bigger body. Based upon these collective observations, researchers say that Ledumahadi was definitely a ‘transitional’ dinosaur, as it had ‘crouched’ yet very thick limbs to support its large body. Their limb bones– both arms and legs – are very robust and similar in shape to giant sauropod dinosaurs but obviously thicker while sauropods had more slender limbs. The evolution of four-legged postures came before their giant bodies. Just sheer size and elephant-like limb posture helped them, example sauropods, to become one of the most dominant dinosaur groups during the Jurassic era. Ledumahadi definitely represents a transitional stage between two major groups of dinosaurs. The group of early dinosaurs were experimenting with various ways of becoming bigger in size during the first tens of millions of years of their evolution. What it means for research is that the evolutionary transition from a small, bipedal creature to a large, quadrupled sauropod is a complex path and this evolution certainly led to survival and achieving dominance.
The discovery published tells us that even more than 200 million years ago, these dinosaurs were the largest vertebrates to be present on the planeta, and this time period was almost 40-50 million years earlier than giant sauropods were first seen. The new dinosaur is closely related to giant dinosaurs who lived in Argentina around that time supporting the idea that all continents that we see today were assembled as Pangea – a supercontinent comprised of world’s land mass during Early Jurassic. And at that time this region of South Africa was not mountainous as we see it today but was flat and semi-arid with shallow streams. Certainly, it was a thriving ecosystem. Like Ledumahadi, many other dinosaurs – both giant and tiny – roamed the place at the time. It is fascinating that South Africa has helped to understand the rise of giant dinosaurs during Jurassic era.
***
{Izvorni istraživački rad možete pročitati klikom na vezu DOI koja se nalazi u nastavku na popisu citiranih izvora}
Izvor (i)
McPhee BW et al 2018. Divovski dinosaurus iz najranije jure Južne Afrike i prijelaz na četveronožje kod ranih sauropodomorfa. Znanost. 28 (19). https://doi.org/10.1016/j.cub.2018.07.063
***
