Pseudotribos belongs in the Shuotheriidae family of the Mammalia class which lived after the Middle Jurassic period, an epoch of the Jurassic Period which lasted from about 174.1 to 163.5 million years ago.
Animalia Chordata Mammalia Shuotheriidae Pseudotribos
Luo et al., 2007 P. robustus The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. 
