The Cladocera Interest Group

Identification

 

IDENTIFICATION

It is interesting that Buglife have a strap line that reads ‘Conserving the small things that run the world’. As county recorder for freshwater invertebrates it is the small things I am concerned with. However it is telling that out of some 28,000 records on my database I have 5,465 beetle records from 136 recorders but only 477 records of water fleas from 14 recorders. Of those 14 recorders only 6 were working in the last 20 years and during the last 10 years only 3 recorders have sent in records. So whilst the small things that run the world have their fans, the smallest things are definitely less popular and, it would seem, have waning popularity. Not surprising when the only English key available at present is 45 years old! .......... Adrian Chalkley

So, what help is available?

The following are easily available, cheap and when used together will enable anyone to get started identifying Cladocera. See also our hints and tips page (coming soon) .....

A Key to the British Species of Freshwater Cladocera, with Notes on their Ecology
D.J. Scourfield & J.P. Harding
Third edition, 1966 (reprinted 1994), 61pp. ISBN 978-0900386-01-5 Freshwater Biological Association ... £10

As stated above this rather old key from the FBA is reprinted from the last 1966 edition and is still available from the FBA website. There is also link to their website on our links page.

There are a number of problems with this key, especially for newcomers to the Cladocera, the main ones being:

A key to the freshwater cladocerans of France and the neighbouring countries of western Europe, 'Crustacés cladocères'
Claude Amoros
Société Linnéenne de Lyon Tome 53 (1984) n°3-4 ... Free (This key has recently been giving problems but is now working again.)

This is a very visual key which is just as well for it is written entirely in French. However non French speakers should not be put off at all. In fact for the rare occasions when the text is not immediately obvious the Google translation service will turn the key-questions into English very well indeed. The author also notes in the abstract that it was written for 'non-specialists'. Fortunately the Micscape website has made the key freely downloadable in pdf form at:
        Microscopy UK, Micscape magazine article library
..... and do also explore the rest of the Micscape site via our links page.

Although this publication is also a quarter of a century or more in age it suffers from slightly fewer of the problems of taxonomic revision than Scourfield & Harding. It does cover some non-British species but includes the vast majority of our own fauna. Where it does score is that the scanning for the pdf download is of sufficient quality to give the illustrations great clarity and so the key features are easily compared with your specimen. This is especially true if using the Amoros key on a laptop next to your microscope which facilitates enlargement at will.

An Updated Key ? What is the best approach?

The FBA has informed us that they are keen to see a new key written and indeed one was started a few years ago but the project eventually came to a halt. So until a new and up to date key is produced the best approach would seem to be to use both of the two keys outlined above in conjunction with an up to date species list.

The updated species list is now available from the Cladocera Interest Group, just go to the downloads link on the left. In April 2013 one of our members Dave Bentley produced a document which allows users to annotate a copy of Amoros in line with the new checklist for Britain & Ireland. This makes it easy to update species names, points out the species in Amoros that do not occur in Britain & Ireland and shows where in Amoros the few unlisted British species would key out. More information on the download page.

Additionally you can also go to our downloads page and save a copy of the NINA posters for 71 British species and compare the information / illustrations as confirmation of your identification.