Theropod（兽脚亚目的） dinosaurs2, a group which includes such famous species as Tyrannosaurus rex and Velociraptor, are often regarded as carnivorous and predatory animals, using their sharp teeth and claws to capture and dispatch prey3. However, a detailed4 look at the claws on their forelimbs（前肢） revealed that the form and shape of theropod claws are highly variable and might also have been used for other tasks. Inspired by this broad spectrum5 of claw morphologies, Dr Stephan Lautenschlager from Bristols School of Earth Sciences studied the differences in claw shape and how these are related to different functions.His research focussed on the therizinosaurs, an unusual group of theropods which lived between 145 and 66 million years ago. Therizinosaurs were very large animals, up to 7m tall, with claws more than 50cm long on their forelimbs, elongated6 necks and a coat of primitive7, down-like feathers along their bodies. But in spite of their bizarre appearance, therizinosaurs were peaceful herbivores.Dr Lautenschlager said: Theropod dinosaurs were all bipedal, which means their forelimbs were no longer involved in walking as in other dinosaurs. This allowed them to develop a whole new suite8 of claw shapes adapted to different functions.In order to fully9 understand how these different claws on the forelimbs were used, detailed computer models were created to simulate a variety of possible functions for different species and claw morphologies.The dinosaur1 claws were also compared to the claws of mammals, still alive today, whose function is already known.In the course of evolution, several theropod groups, including therizinosaurs, changed from being carnivores to become plant-eaters. This new study reveals that, during this transition, theropod dinosaurs developed a large variety of claw shapes adapted to specific functions, such as digging, grasping or piercing.Dr Lautenschlager said: Its fascinating to see that, with the shift from a carnivorous to a plant-based diet, we find a large variety of claw shapes adapted to different functions. This suggests that dietary adaptations were an important driver during the evolution of theropod dinosaurs and their transition to modern birds.
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1 dinosaur n.恐龙 参考例句： Are you trying to tell me that David was attacked by a dinosaur你是想要告诉我大卫被一支恐龙所攻击？ He stared at the faithful miniature of the dinosaur.他凝视著精确的恐龙缩小模型。
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