Introduction to Multituberculates The Lost Tribe of Mammals
Multituberculates are the only major branch of mammals to have
become completely extinct, and have no living descendants.
Although not known to many people, they have a 100 million-year
fossil history, the longest of any mammalian lineage. These
rodent-like mammals were distributed throughout the world, but
seem to have eventually been outcompeted by true rodents.
Multituberculates first appeared in the Late Jurassic, and went
extinct in the early Oligocene, with the appearance of true
rodents. Over 200 species are known, some as small as the
tiniest of mice, the largest the size of beavers. Some, such as
Lambdopsalis from China, lived in burrows like prairie dogs,
while others, such as the North American Ptilodus, climbed trees
as squirrels do today. The narrow shape of their pelvis suggests
that, like marsupials, multituberculates gave birth to tiny,
undeveloped pups that were dependent on their mother for a long
time before they matured. Pictured