Ammothea hilgendorfi

Phylum: Chelicerata
Class: Pycnogonida
Order: ------
Species name: Ammothea hilgendorfi (Böhm 1879)
Synonyms: Leionymphon hilgendorfi Böhm 1879
Common name: A sea spider
Date of introduction and origin
Ammothea hilgendorfi was first observed in 1978 in Southampton Water (Bamber 1985). This species is thought to have been introduced from Japan. It originates in the tropical and temperate North Pacific littoral zone of south-east Asia.
Method of introduction
It is transported on ships' hulls.
Reasons for success
Rate of spread and methods involved
Rate of spread is minimal without assistance from man (R.N. Bamber pers. comm.).
Currently it is known in Britain only from Southampton Water (Bamber 1988). Elsewhere in Europe it has been found in a lagoon in Venice.
Factors likely to influence spread and distribution
There is no dispersive phase in the species' life cycle which means dispersal is very slow.
Effects on the environment
Effects on commercial interests
Control methods used and effectiveness
Beneficial effects
None known.
This is a species of no ecological or commercial significance. Introduction to the lagoon in Venice is also presumed to have been on a ship's hull.
Chocolate brown markings on the trunk and legs (as indicated in the illustration) are a useful aid to identification.
Bamber, R.N. 1985. The itinerant sea spider Ammothea hilgendorfi (Böhm) in British waters. Proceedings of Hampshire Field Club & Archaeological Society, 41: 269-270.
Bamber, R.N. 1988. Confirmation of a new record. Porcupine Newsletter, 4: 37.
Acknowledgements (contributions from questionnaire)
Dr R.N. Bamber, Aquatic Research Laboratories Ltd, Southampton.