Thomas's pygmy jerboa is a tiny jerboa with a 5.7 cm head-and-body length and a 10.5 cm tail. It is known from a single type specimen from southeastern Afghanistan, and much of its ecology is unknown.
The type specimen measures 57 mm from head to body and 105 mm in tail length. Its hind feet have three toes with brushes of hair underneath, and its ears are short and tube-shaped.
The treatment says the habitat is probably sandy desert. It reports no information on food, activity patterns, breeding, or home range.
An extinction-risk assessment has not been added yet.