[5] The leptictids are a characteristic example of the non-specialized placental mammals that took part in the late Cretaceous-Paleocene evolutionary radiation, originally bunched together in the order Insectivora.

Leptictid postcranial anatomy has been studied from the well-preserved middle Eocene Leptictidium specimens found at Messel, Germany.

The head had a long and slender snout, probably featuring a short trunk, which may have been used for scratching the undergrowth in search of insects and worms.

While this anatomy is reminiscent of small kangaroos and jerboas, suggesting a jumping locomotion, the structure of the tarsal bones hints at a specialization for terrestrial running.

Additionally, the Messel specimens feature a surprisingly long tail, unique among modern placental mammals, formed by 40 vertebrae and probably used for balance.