Topic: Gordius (hairworm, Nematomorpha)

Gordius villoti was the recommended name for the Gordius recorded in Britain on the basis that Linnaeus' original Gordius aquaticus was not sufficiently well described. However, Andreas Schmidt-Rhaesa (2010 Zootaxa 2533: 1-35) has re-examined the argument for using the name Gordius aquaticus and now considers it valid and that villoti is probably a separate species.

In the last decade he has also described various new Gordius species from mainland Europe. I don't know that any of them have been recorded in Britain, but that might be just because he has not had any British specimens to examine. The characters he uses are only visible using electron microscopy. So I suggest all Gordius aquaticus/villoti records are reduced to Gordius sp. unless they have been identified using EM.


Re: Gordius (hairworm, Nematomorpha)

Hi John, currently we have both as distinct species and recorders should be able to add records as the genus Gordius if they want. Do you think it might be useful to create a G.aquaticus/villoti species aggregate and sink the 2 species under it? I would be tempted to wait if there is no definitive review of the UK species.

Chris Raper, Manager of the UK Species Inventory, Angela Marmont Centre for UK Biodiversity,
Natural History Museum, Cromwell Road, London, SW7 5BD.  (tel: 020 7942 5894)
also Tachinid Recording Scheme (http://tachinidae.org.uk/)


Re: Gordius (hairworm, Nematomorpha)

I'm not sure an aggregate aquaticus/villoti is the right answer. To a Nematomorpha taxonomist, that would imply those two are more closely related than the other new Gordius spp., and I don't know that is the case.  I think it would be best if records were changed to genus only, but I guess that is a job for the dataset owners. It isn't a huge problem - only one villoti record, mine and I've flagged it; and only two aquaticus records. So as you say, maybe best to wait for a proper review of what species occur in Britain.