Parasitic mites associated with spiders are spreading world-wide through the trade in tarantulas and other pet species.
Ljunghia pulleinei Womersley, a mesostigmatic laelapid mite originally found in association with the mygalomorph spider
Selenocosmia stirlingi Hogg (Theraphosidae) in Australia, is redescribed and illustrated on the basis of specimens from the
African theraphosid spider Pterinochilus chordatus (Gersta¨cker) kept in captivity in the British Isles (Wales). The mite is known
from older original descriptions of Womersley in 1956; the subsequent redescription of Domrow in 1975 seems to be
questionable in conspecificity of treated specimens with the type material. Some inconsistencies in both descriptions are
recognised here as intraspecific variability of the studied specimens. The genus Arachnyssus Ma, with species A. guangxiensis
(type) and A. huwenae, is not considered to be a valid genus, and is included in synonymy with Ljunghia Oudemans. A new
key to world species of the genus Ljunghia is provided