The American Museum of Natural History Photograph # 311488 demonstrates an articulated skeleton of a Psittacosaurus mongoliensis, from the Ondai Sair Formation, Lower Cretaceous Period of Mongolia, showing a collection of about 40 gastroliths inside the rib cage, about midway between shoulder and pelvis.
A fotografía # 311488 do Museo Americano de Historia Natural (á dereita) dun esqueleto articulado dun Psittacosaurus mongoliensis, da Formación Ondai Sair, do Cretáceo inferior de Mongolia, mostra un conxunto de 40 gastrólitos dentro da caixa torácica, a medio camiño entre o ombro e a pelve.