Checklist of British Marine Mollusca

At last we have an up-to-date taxonomy for the British marine mollusc fauna - and for most of north west Europe too.

A three page introduction discusses the need for a new list, the classification, taxonomy and sources used, and explains the useful system of suffixes denoting brackish, littoral or deepwater species, and those of a southern or northern distribution. There follows a five page systematic list of higher taxa, and then the checklist itself, occupying the bulk - 70 pages - of the work. Copious annotations, indicated by marginal numbers in the checklist, cover the next nine pages, and it ends with five pages of references and a very full 20 page index down to species and variety level, which includes all synonyms. Layout is clear, with good use of different headings, type and indents.

The title British is modest and confusing; the area covered includes Ireland and the French Channel coast, and extends into deep Atlantic water well north of the Faroes, 200 miles west of Ireland and 450 miles south west of Land's End, yet stops short only 40 miles east of East Anglia (02 degrees 40 minutes). The authors then extend the area - and the list of species - by use of a prefix to:

'. . . indicate a species which has not as yet been recorded from the present area but which has been found within 1 degree of latitude or longitude of our limits, and thus might reasonably be expected to occur there'.

This increases the taxonomic value, but should be treated with caution biogeographically; sources for records of the occurrence of prefixed species are not given, and I suspect that the Smith & Heppell '1 degree' is like the countryman's mile - as far as is required! For instance, Norwegian coastal species are included, and one would have to go 7 degrees east to find the nearest Parvicardium hauniense. Choice of an area including the whole North Sea, with a 'North west Europe' title would have been more satisfactory and less confusing.

Others are better qualified than I to comment upon the taxonomy and nomenclature, but there are some errors. Most of these are in citation of authorship of taxa, particularly of date of publication, e.g., Elysia Risso, 1818, not 1826 as shown; Chrysallida indistincta (Montagu, 1808), not 1803; Hiatella arctica (L., 1767), not 1758, Hemiaclis ventrosa is attributed to G. 0. Sars, whereas it should be to Jeffreys in Friele, etc. They are unfortunate in a work which claims that'. . . compared with many authors we have investigated more widely . . . particularly in ... the citing of the correct authorship and date . . .'.

For the Caecidae, the authors follow Aartsen's 1977 review, so including Caecum armoricum only as a synonym of C. glabrum - wrongly, since they have overlooked Aartsen's 1984 revisions with Hoenselaar (Basteria, 48: 23-26) and with Menkhorst and Gittenberger (Basteria, suppl., 2:27), in which armoricum was (and still is; pers. comm.J.J. van Aartsen) considered a good species. This is notwithstanding an acknowledgement to (among others) Aartsen with whom the authors 'have engaged in lengthy correspondence and discussion'. The authors tell me that they are preparing an 'Addenda and Corrigenda' to send out to all who have received a copy.

I would not have expected Theodoxus ftuviatilis in a British marine list, even as a brackish water species, although it does live in the Baltic in reduced salinity. Rissoa labiosa is also shown as a brackish water species although I suspect that usually it is found in full salinity; conversely, Assiminea grayana is listed as littoral @ surely a mistake for this obligate brackish water animal. It is surprising to sec Aplysia parvula in the list without comment; the occurrence of this species in British waters is still subject to confirmation (A. Bebbington, pers. comm.).

It should be noted that there are considerable differences in classification and nomenclature from the earlier list by Smith (in C. M. Howson (ed.), 1987, Directory of the British marine flora and fauna. Marine Conservation Society), which must now be regarded as superseded, although this is not specifically stated. Some mention of the Annotated checklist of Mediterranean marine mollusks by Sabelli, Gianuzzi-savelli & Bedulli, published in 1990 by Libreria Naturalistica Bolognese, with comments on points of difference of taxonomic treatment, would have been valuable since many species occur in both lists.

In spite of some minor faults, Smith and Heppell are to be congratulated for giving us a valuable, workmanlike and usable document which should receive widespread adoption.