[3] A 2016 study lumped the genus back within the Palaeotheriidae.

[1] The species P. parvulum and P. messelensis have been alternately assigned to the equid genus Eurohippus.

[4] Propalaeotherium was a small animal, ranging from 30–60 cm at the shoulder (2.9 to 5.9 hands), and weighing just 10 kg (22 lb).

It had no hooves, but instead several small nail-like hooflets.

The well-preserved Messel fossils showed their herbivory, specifically their preference to eat berries and leaf matter picked up from the forest floor.