الطيور القديمة قطعة قراءة ستيب رقم 78

نص القطعة

1-Giant birds of the past have names that speak for themselves. The elephant bird, a native of Madagascar and the largest known giant bird, stood at over nine feet tall and weighed in at a whopping 1,000 pounds or more, until it went extinct about 1,000 years ago. Australia’s mihirung, nicknamed “thunder bird,” which disappeared nearly 50,000 years ago, is thought to have been nearly seven feet tall and weighed between 500 and 1,000 pounds. But until now, no one had ever found evidence of these towering avians in Europe. 2-A team of paleontologists dug up the fossil—an unusually large femur—in Taurida Cave, located on the Crimean Peninsula in the northern Black Sea. The cave was only discovered last June when the construction of a new highway revealed its entrance. Initial expeditions last summer led to exciting finds, including the bones and teeth of extinct mammoth relatives. Of course, the team didn’t expect to find large birds, since there had never been evidence of their existence in Europe. 3-“When these bones reached me, I felt like I was holding something belonging to elephant birds from Madagascar,” paleontologist Nikita Zelenkov of the Borissiak Paleontological Institute, who lead the study, says in an email. “This was the most surprising [part] for me, such an incredible size. We did not expect [that].” 4-Based on the femur’s dimensions, the team calculated that the bird would have weighed around 992 pounds—as much as an adult polar bear—making it the third largest bird ever recorded. 5-Although the bone was similar in size to an elephant bird’s femur, it was more slender and elongated, like a larger version of the modern ostrich (Struthio camelus). “The main difference from Struthio is the notable robustness. There are also some less visible details, like the shape or orientation of particular surfaces, which indicate a different morphology from ostriches,” Zelenkov says. 6-The femur’s shape also gives us clues about what the world was like when Pachystruthio was alive. Its similarities to the bones of a modern ostrich suggest that enormous bird was a good runner, which could imply that it lived among large carnivorous mammals like the giant cheetah or saber-toothed cats. This idea is supported by the earlier findings of nearby bones and fossils. 7-Perhaps most notably, the team hypothesizes that Pachystruthio was present when Homo erectus arrived in Europe during the Early Pleistocene and possibly arrived via the same route. Knowing that the two ancient species could have coexisted introduces a world of new questions for scientists. 8-“The thought that some of the largest birds to have ever existed were not found in Europe until so recently is revelatory,” Daniel Field, a paleontologist at the University of Cambridge who was not involved in the new research, says in an email. “[It] raises exciting questions about the factors that gave rise to these giant birds, and the factors that drove them to extinction.