化石证据表明,在大约2.3亿年前恐龙就已经出现在地球上了,在随后约1.6亿年的演化历史中内它们进化出各种体型,并占据了大部分陆地生态系统。但在恐龙时代的头3000万年里,热带地区只有寥寥数种体型很小的肉食性恐龙存在,大型草食性恐龙很罕见,这种现象在古生物学上成为一个谜。为了解恐龙时代早期热带地区 Fossil evidence shows that about 230 million years ago dinosaurs had appeared on Earth, and within about 160 million years of evolution they evolved a variety of body types and occupied most of the terrestrial ecosystems. But in the first 30 million years of the dinosaurs, there were only a few species of carnivorous dinosaurs in the tropics. Rare herbivorous dinosaurs were rare, a phenomenon that has become a mystery in paleontology. To understand the early dinosaurs tropical regions