學名：Psittacosaurus（鸚鵡嘴龍屬）
年代：中生代白堊紀
發現地：中國
說明：
鸚鵡嘴龍（屬名：Psittacosaurus），在希臘文中意為「鸚鵡蜥蜴」，是個十分貼切的名字，因為屬於爬蟲類的鸚鵡嘴龍事實上是使用後方雙足站立、行走，各位不妨想像一下牠們行動的樣子，再搭配上如鳥類的喙，是不是跟鸚鵡有點相似呢？
Psittacosaurus, Greek for “parrot lizard”, is quite a fitting name for the fossil you see before you. In fact, the reptilian Psittacosaurus were bipeds and had a robust beak. Imagine its movement, and you can see its similarity to a parrot.
要說到牠們與鳥類的相似處，就一定要提到「砂囊」了！因為鸚鵡嘴龍沒有適合磨碎植物的牙齒，所以會吞食小石子到胃裡協助消化，有時在牠們胃裡發現的胃石甚至超過50顆。
When it comes to other similarities that it shares with birds, we cannot ignore its gizzard, an organ commonly found in many modern birds. Because the Psittacosaurus do not have suitable teeth for grinding plants, they swallow small stones known as gastroliths to assist digestion. Sometimes, more than fifty gastroliths can be found in their stomachs.
此外，鸚鵡嘴龍為目前所知最完整的恐龍，因為擁有400個以上個體出土，使科學家、古生物學家對於其研究突飛猛進，又因為廣泛分布的特質，鸚鵡嘴龍也常被當作標準化石協助判斷地層分類。
Psittacosaurus is one of the most completely known dinosaur genera currently discovered. More than 400 specimens have been excavated, allowing scientists to rapidly advance research on the genus. Owing to its wide distribution, they have been utilized as index fossils to determine geologic layers.