Palpigradi: Ecology & Faunistics
Palpigrades have been reported from latitudes between 49°N and 33°S and from altitudes between sea level and about 2000 m. All known palpigrade species live in subsurface habitats such as soil, littoral sand, caves, and gravel deposits. Inhabitants of small pore habitats are thin and have short appendages, whereas cave dwellers often display troglomorphy, having a big stout trunk and long appendages.
The genus Eukoenenia occurs in all biogeographic regions and comprises three quarters of known palpigrade species. Only in the Palearctic do troglobiont palpigrade species clearly prevail over soil-dwelling species (30:4), which cannot be explained by uneven or biased sampling alone. Species-level endemism is generally high in Palpigradi. A small handful of species have been widely dispersed by human agency.