Upon their initial discovery, Jenkins and coauthors (2005) considered the Laotian rock rat to represent a completely new family. The discovery of a new species of an extant mammal genus, or a new genus, happens periodically, such as with the leaf muntjac or the saola. The discovery of a completely new family is, by comparison, much more unusual. The most recent incident before the discovery of the family Laonastidae by Western science was the discovery of the bumblebee bat ("Craseonycteris thonglongyai"; family Craseonycteridae) in 1974. The only other examples from the 20th century are species that are only considered distinct families by a few authorities. These discoveries are: the Chinese river dolphin ("Lipotes vexillifer"; family Lipotidae) in 1918, the Zagros mouse-like hamster ("Calomyscus bailwardi"; family Calomyscidae) in 1905, and Goeldi's marmoset ("Callimico goeldii"; family Callimiconidae) in 1904. Representatives from all the remaining rodent families with living representatives (approximately 30) were discovered before 1900.