[3] The oldest putative representatives of the family herald from Burmese amber dated to the mid-Cretaceous, around 100 million years ago, with representatives from Dominican and Baltic amber attesting to a broader distribution in the Palaeogene / Neogene; molecular variability suggests that the family's crown group may have arisen in the early Mesozoic.

[8] There are no known oviparous species—the overwhelming majority, including all the Neotropical Peripatidae, are viviparous with females that develop a placenta to provide the growing embryo with nutrients.

[10] The Asian genera Typhloperipatus and Eoperipatus, however, exhibit lecithotrophic ovoviviparity; that is, their females do not develop any placenta and instead retain yolky eggs in their uteri to supply nourishment.

[10] The Peripatidae, also known as equatorial velvet worms,[11] are restricted to the tropical and subtropical zones; in particular, they inhabit Central America, the Caribbean, northern South America, Gabon, Northeast India, and Southeast Asia.

[13] The excluded peripatid genera are the southeast Asian †Cretoperipatus and Eoperipatus, the African Mesoperipatus, and the northeast Indian Typhloperipatus.