Scientists have shown that the short forelimbs of Tyrannosaurus rex\nwere not merely a consequence of its colossal body size but part of a\nmajor shift in hunting strategy among predatory dinosaurs. The study,\nled by researchers from University College London (UCL) and the\nUniversity of Cambridge and published in Proceedings of the Royal\nSociety B, analysed 82 theropod species, a two-legged group of\npredominantly carnivorous dinosaurs. The results indicate that short\narms evolved independently in at least five lineages of predatory\ndinosaurs, including the tyrannosaurids that include T. rex.<\/p>\n
Researchers found that dinosaurs with short arms generally possessed\nlarge, highly robust skulls. This relationship appears stronger than any\nlink between arm size and overall body size.<\/p>\n
The team suggests the change may reflect predators increasingly\nrelying on deadly bites rather than claws when hunting giants such as\nsauropods.<\/p>\n
Lead author Charlie Roger Scherer said the head and jaws gradually\nassumed the primary role in striking prey. \u2018This is a use\u2011it\u2011or\u2011lose\u2011it\nprinciple. As the arms became less necessary, their size continued to\nshrink through evolution,\u2019 he said. He added that using claws to grasp\nvery large sauropods was less effective than striking with a powerful\njaw.<\/p>\n
In the study, T. rex was identified as the dinosaur with the\nstrongest skull. Tyrannotitan occupied the next position, a giant\npredator that lived in what is now Argentina millions of years before T.\nrex. The researchers hypothesise that the emergence of giant herbivores\ntriggered an \u2018evolutionary arms race\u2019 in which predators developed\nsturdier skulls and jaws to subdue ever-larger prey.<\/p>\n
Beyond the tyrannosaurids, the study identified several other\ntheropod groups that show reduced forelimbs, including Abelisauridae,\nCarcharodontosauridae, Megalosauridae and Ceratosauridae. One example is\nMajungasaurus, which had very small arms and a robust skull despite\nbeing much smaller than T. rex.<\/p>\n
The researchers found that each group underwent short\u2011arm evolution\nin different ways. Some reduced the hand and forearm, while others\nreduced the size of the forelimb more evenly across the entire forelimb.\nThe scientists conclude that various predator dinosaurs may have reached\nsimilar evolutionary outcomes via different developmental pathways.<\/p>\n
Source: Science Daily<\/p>\n
Based on fossil embryos and juvenile specimens, baby T. rex\nhatchlings are estimated to measure around 90 to 120 centimetres in\nlength.<\/p>\n
Is it true that T\u2011Rex had intelligence on a par with modern birds?\nSee Prof.\u00a0Steve Brusatte\u2019s latest findings on the evolution of dinosaurs\ninto the birds we know today.<\/p>\n
The researchers studied 17 tyrannosaur specimens across different\nages to construct a more accurate growth picture.<\/p>\n
Tyrannosaurus rex (T\u2011Rex) is known as the apex predator of the\ndinosaur era. Its jaw was exceptionally powerful, making it seem\nvirtually unbeatable.<\/p>\n
Now, a new study published in Nature provides the answer that\nNanotyrannus is a distinct species, not a juvenile T. rex.<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/scientists-find-reason-for-the-evolution-of-short-arms-in-predatory-dinosaurs-1779542473", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }