Catopsbaatar
Catopsbaatar is a genus of multituberculate, an extinct order of rodent-like mammals. It lived in what is now Mongolia during the late Campanian age of the Late Cretaceous Period, about 72 million years ago. The first fossils were collected in the early 1970s, and the animal was named as a new species of the genus "Djadochtatherium " in 1974, "D. catopsaloides". The specific name refers to the animal's similarity to the genus "Catopsalis". The species was moved to the genus "Catopsalis" in 1979, and received its own genus ("Catopsbaatar", Greek and Mongolian for "visible hero") in 1994. Five skulls, one molar, and one skeleton with a skull are known; the latter is the genus' most complete specimen. "Catopsbaatar" was a member of the family Djadochtatheriidae.
Timeline of ceratopsian research
The early 20th century was a fruitful time for ceratopsian research. In 1907, Hatcher and others published a monograph on ceratopsid anatomy that is still considered the single most significant publication on the topic to date. Many new species were being described, including "Centrosaurus", "Styracosaurus", and "Chasmosaurus". Not long after, the Central Asiatic Expedition led by Roy Chapman Andrews of the American Museum of Natural History discovered the primitive ceratopsians "Psittacosaurus" and "Protoceratops" in Mongolia. "Protoceratops" gained notoriety as the supposed parent of the first fossil dinosaur eggs known to science. One of these supposed "Protoceratops" nests preserved the skeleton of a new kind of theropod dinosaur, "Oviraptor". It was thought to have been preserved after being killed in the act of raiding the "Protoceratops" nest. This narrative would last until the , when the ""Protoceratops"" eggs were determined to belong to "Oviraptor" itself.