There are two families and 110 living species. All living species are terrestrial, in moist or wet tropical areas. However, the phylum goes back to the Cambrian, and all the early specimens are from marine strata.
The two living families are the Peripatidae and the Peripatopsidae. They show a peculiar distribution, with the peripatids being predominantly equatorial and tropical, while the peripatopsids are all found in what used to be Gondwana.
The segmented worm-like organisms have tiny eyes, antennae, multiple pairs of legs and slime glands. The group is thought to be related to arthropods. They prey on smaller animals such as insects, which they catch by squirting a sticky slime.
- Peripatus is the textbook example of this phylum. It lives in the former Gondwana (southern) continents.
- Piper, Ross 2007. Extraordinary animals: an encyclopedia of curious and unusual animals. Greenwood Press.