Bryceomys is an extinct mammal that lived during the late Cretaceous period (between 100 and 66 million years ago) and thus shared the world with dinosaurs.

The species Bryceomys fumosus (Eaton 1995) is known from fossils found in strata dating to the Turonian (Upper Cretaceous) in the Straight Cliffs Formation of Utah, US.

About a hundred teeth are held at the Oklahoma Museum of Natural History, including the holotype.

1995 Place: Straight Cliffs Formation of Utah Age: Turonian (Upper Cretaceous) Also in the Oklahoma collection.

Suggested bodyweight is around 90 g. Species: Bryceomys intermedius Eaton JG & Cifelli RL, 2001 Place: Cedar Mountain Formation, Utah Age: Albian (late) - Cenomanian (early) (Upper Cretaceous)