【英语时差8,16】还有小恐龙？
时间：2016-01-25 06:41:25
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（单词翻译）
Yaël: Don, when I say "
dinosaur1" what do you picture?
Don: Huge reptile-like creatures like Tyrannosaurus rex or the long-necked brachiosaurus?
Y: Me too, but do you know there were also tiny
dinosaurs2? In recent years, palaeontologists have
unearthed3 some of the smallest dinosaurs known. In the late 1990s two tiny species of Theropods were discovered in China and Mongolia. The Theropod group contains carnivorous dinosaurs that walked on two legs, like T. rex and velociraptors. The newly discovered "tiny-osaurs" were both under two feet long and probably weighed less than your Thanksgiving turkey.
In 2002, the smallest North American dinosaur was uncovered in Alberta, Canada. This
puny4 Theropod is also unique because it probably dined on insects. Most other Theropods were meat-eaters.
D: How do we know these aren't just fossils of baby dinosaurs?
Y: One way to tell is by examining the growth rings in bones. In some bone tissue, layers are created as the bone grows, sort of like the rings of a tree. The bones of older animals grow more slowly, so the rings get closer together. This allows scientists to identify if the bones are from adults or
juveniles5.
Another way to tell is when several fossils are found together that include adults and juveniles---like the discovery of the smallest Sauropod species in Germany in 2006.
The Sauropod group contains the giant, long-necked, plant-eating dinosaurs that walked on four legs---like the eighty-foot long brachiosaurus. But the new species from Germany are much smaller---about twenty feet long as adults, and some juveniles are only four feet long.
D: Well, now when I think "dinosaurs" I'll think "teenie-weenie."
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