If this is due to a common ancestor, or to the unusual mode of locomotion used by these animals (graviportal and plantigrade) remains a mystery to be seen. However, Gaudry (1909) himself established that Pyrotherium was sufficiently different from any other group of large mammals that it should have its own order, with no clear relation to other mammals.
The mystery surrounding the origins of these animals' unique characteristics, whether attributed to a shared ancestor or their unusual locomotion (graviportal and plantigrade), remains unsolved. Gaudry (1909) concluded that Pyrotherium was distinct enough from other mammals to warrant its own order, with no clear connection to any existing mammal groups.