Class Mammalia Linnaeus, 1758 - mammals
Order Rodentia Bowdich, 1821 - rodents
Suborder Sciurognathi (Tullberg, 1899)
see Suborder Sciuromorpha Brandt, 1855
Family Sciuridae Batsch, 1788 - squirrels, chipmunks, marmots, and prairie dogs
Subfamily Sciurinae Batsch, 1788 - tree and ground squirrels
Genus Exilisciurus Moore, 1958 - pygmy squirrels
1 Exilisciurus concinnus Thomas, 1888 - Philippine pygmy squirrel
2 Exilisciurus exilis Müller, 1838 - plain pygmy squirrel
3 Exilisciurus whiteheadi Thomas, 1887 - Whitehead's pygmy squirrel