Meniscoessus is a genus of extinct multituberculates from the Upper Cretaceous Period that lived in North America.

They were significant for having diverged early in mammalian evolution, co-existing with dinosaurs for ~100 million years, surviving through the Cretaceous–Paleogene extinction event and lasting until the end of the Paleogene, likely having been replaced by true rodents.

This was a period of significant diversification of multiturbiculates, and evidence that contradicts the popular misconception that mammals were unable to thrive due to being outcompeted by the dinosaurs.

[citation needed] Close similarities were then noticed with an already established dinosaur genus, Paronychodon (Cope 1876), also based on teeth from the Laramie Formation.

[citation needed] Over time, an impressive school of names was synonymized under P. However, this is now considered a nomen dubium.