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A (KONTRIBUTION TO THE CENSUS OF THE NON-MARINE MOLLUSCA OF SUFFOLK H. E. J. BIGGS, F.L.S. THE Conchological Society of Great Britain and Ireland (founded 1876) has maintained a census of the non-marine mollusca of the British Isles from its earliest days and the first census report was published in 1885. This was on a county and vice-county basis. T h e last edition, the seventh, appeared in October, 1951, with a Supplement in June, 1966. T h i s basis was found to give a rather inadequate, and in some cases quite inaccurate, picture of the precise distribution of certain species and a much smaller unit of area was necessary. For instance, in East Anglia, Norfolk and Suffolk were each divded into vice-counties, Norfolk East and West and Suffolk East and West, by the meridian of longitude 1° East of Greenwich. Essex was divided by an arbitary line drawn across the county, following certain roads, into Essex North and Essex South. T h e result of this was that on the distrubtion map of a species which had a limited distribution and which lived in a few specially favourable localities, the whole of East Anglia would be blacked in. T o correct this a mapping scheine was adopted in 1962 based on the 10 km. squares of the Ordnance Survey Maps and put undcr direction of Dr. M . P. Kerney of the Imperial College of Science. For the purpose of the new census only records made since 1950 were accepted thus not only would a more accurate knowledge of the distribution of a species be built up but many old records checked and changes in distribution revealed. Some would prove to have extended their distribution, some beeil diminished and others even become extinct. As there are some 3,500 10 km. squares in the British Isles and nearly 180 species of non-marine mollusca on our list the task projected was prodigeous. Iiowever, already, a great n u m b e r of new records have been made ar.d a glance at the most recent map which has been compiled as a result of these new records received up to January, 1968, reveals the following Situation. Ireland has been scarcely touched; Scotland has received a little more attention; Wales and central England only fairly covered. T h e rest of England has had quite appreciable attention. A useful four-page paper has been produced by Dr. Kerney entitled 'Notes for the guidance of recorders' and is available from him to potential workers. In our area of Suffolk, in ordcr to cover the whole county, records must be made for fifty-five squares which lie wholly or in part in the county. Dr. Kerney informs me (in litt.) that he has records of over forty species for only seventeen of these squares and adds 'anything less than this must be considered poor'. In


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short a vast a m o u n t of collecting, checking determinations and recording has yet to be done before we can get even a moderately clear conception of the molluscan fauna of our county.

Historical T u r n i n g over the pages of the Transactions of the Suffolk Naturalists' Society little seems to have been written on mollusca, except for a few useful notes, in recent years. T h e most comprehensive attempt to record Suffolk non-marine mollusca was made by A r t h u r Mayfield of M e n d l e s h a m (18691956) and the results of his work were published in 'The Journal of Conchology' in 1903, 1906, and 1909. However, the first list to be published was that of Green (1891) and the last that of Morley (1940). T h e latter included non-marine mollusca in a general s u m m a r y of all the molluscan records for the county which were known to him to date. Apart f r o m a few notes in some journals no a t t e m p t at a comprehensive review of the mollusca of the county has been m a d e for twenty-eight years.

The New Census For the present State of the new census so far as Suffolk is concerned see MAP (p. 186). T h i s is the work of several competent observers. In order to assist with this, and as I was closely connected with Aldeburgh, I began in 1964, to record the local species, b u t the progress was slow and so it was decided to make a more determined effort to cover the Square. W i t h the help of M r . L. W . Stratton of H a r p e n d e n , who provided a car, and what was perhaps more important, a wide knowledge of the British species, a more intensive search was made in 1967 and 1968. W e also decided to cover three of the adjacent squares and the result is shown in the T A B L E below Species Viviparus contectus Miller Valvata piscinalis (Müller) Valvata cristata Müller Hydrobia ventrosa (Montagu) Hydrobia ulvae Pennant Hydrobia neglecta M u u s Potamopyrgus jenkinsi (Smith) Bithynia tentaculata (Linne) Bithynia leachii (Sheppard) Assiminea grayana Fleming Carychium tridentatum (Risso) Phytia myosotis Draparnaud Lymnaea truncatula (Müller) Lymnaea palustris (Müller) Lymnaea stagnalis (Linne) Ly mnaea auricularia f 1.Inno) Lymnaea peregra (Müller) Aplexa hypnorum (Linne) Physa fontinalis (Linne)

Wickham Market TM3 5

Aldeburgh Saxmundham TM36 TM45

Leiston

TM46 X X X

X X X ?

X

X X X X

X

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X X X

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X X

X

X

X

X

X

X


184 Transactions of the Suffolk Naturalists', Vol. 14 (continued)

X X

X X X

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TMjti

X K> X X X X X X X X X X X X X X X

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X X X X X

TM.

X X X X X X X

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X X X X

X

X X

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XX

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X X X

X X X X X X X

X X X X X X

X X

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X X X X X X X X

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XXX

XX X X X

Species Planorbarius corneus (Linne) Planorbis carinatus Müller Planorbis planorbis (Linne) Planorbis vortex (Linne) Planorbis leucostoma Millet Planorbis albus Müller Planorbis contortus (Linne) Segmentina complanata (Linne) Acroloxus lacustris (Linne) Succinea putris (Linne) Succinea pfeifferi Rossmässler Cochlizopa lubrica (Müller) Lauria cylindracea (da Costa) Vallonia costata (Müller) Marpessa laminata (Montagu) Clausilia bidentata (Ström) Cepaea hortensis (Müller) Cepaea nemoralis (Linne) Helix aspersa (Müller) Hygromia striolata (C. Pfeiffer) Hygromia hispida (Linne) Hygromia liberta (Westerlund) Monacha granulata (Alder) Monacha cantiana (Montagu) Monacha cartusiana (Müller) Helicdla caperata (Montagu) Helicella gigaxii (L. Pfeiffer) Helicella virgata (da Costa) Discus rotundatus (Müller) Arion circumscripta Johnson Arion ater (Linne) Arion ater ssp. rufus (Linne) Arion subfuscus (Draparnaud) Euconulus fulvus (Müller) Vitrea crystallina (Müller) Oxychilus drapamaldi (Beck) Oxychilus cellarius (Müller) Oxychilus alliarius (Miller) Retinella pura (Alder) Retinella nitidula (Draparnaud) Retinella radiatula (Alder) Zonitoides nitidus (Müller) Vitrina pellucida (Müller) Limax flavus Linne Lehmannia marginata (Müller) Agriolimax reticulatus Müller Agriolimax laevis (Müller) Anodonta cygnaea (Linne) Anodonta anatina (Linne) Sphaerium corneum (Linne) Sphaerium lacustre (Müller) Pisidium pulchellum Jenyns Pisidium casertanum (Poli) Pisidium milium Held Pisidium subtruncatum M a l m Pisidium nitidum Jenyns

Wickham Market TM35


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Some c o m m e n t s on the recorded species Assiminea grayana Fleming. Morley (1940) reports as follows, 'Several discovered at Aldeburgh in June, 1906; one at the mouth of the R. Orwell in Julv, 1907 by Mayfield, and one in R. Blyth at Blythburgh by A. S. Kennard, F.G.S., before 1908 . . ' We can assume that this was about the time of the beginning of the colonisation of this area by the species; today the population of one drain at the corner of the Aldeburgh Marshes near Slaughden is enormous. Hydrobia neglecta Muus. This species is included in the list with a ?. I collected a large number of Hydrobia spp. on the Aldeburgh Marshes in 1964 and 1965 and several appeared tohave, not only the shape and size as described by Muus, but also the pigmentation of the head and tentacles. Unfortunately I was not able to study the form and shape of the penis which is an important diagnostic character. This species should be searched for on Blythburgh Marshes also. Monacha cartusiana (Müller). For some time the precise status of this species in Suffolk has been in question. From records known to me the only live occurrence was that recorded by Mayfield (1903) who writes, 'There is a flourishing colony of this species on a chalky hedge-bank at Needham Market.' In 1909 he added, 'In a pit at Little Glemham (G.T.R.)'. This observer is Mr. G. T. Rope of Blaxhall, near Wickham Market. Unfortunately there is nothing to show if this latter colony was one of live shells, or whether he only found a few dead shells as has been the case several times in East Anglia. There is also a record of one dead shell at Great Fakenham (Mayfield, 1906). Morley's reference (1940) to ' . . . Glemham Parva (Gr.1903)' may be to the same pit as the one in which Rope found the species. But Green's 1903 list was of Marine Mollusca, so the record is suspect. Mr. R. Fresco-Corbu, of Westcliff-on-Sea, Essex, visited the Needham Market site in the summer of 1968 and reported no trace of the species, not even dead shells. This means that since Mayfield's record (1903) of shells collected by him alive in 1902 no record of live shells of this species has been made in Suffolk for sixty-six years until this species was found by Mr. Stratton in October, 1968, a few miles from Saxmundham. Only one live shell was found and two dead ones, it can be assumed that this colony too may be on the verge of extinction and so preservation of the site is of the utmost importance. Discus rotundatus (Müller). Morley (1940) records, 'Goniodiscus (H) rotundatus, Müll.—Abundant everywhere: Monks Soham'. Our experience was that after careful search in the Aldeburgh Square we found no example of this normally extremely common


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species. Although found in the other three squares it was far from common. Vitrina pellucida (MĂźller). The examples taken at Snape in October, 1967, were all alive and active. They were found in litter round the roots of nettles and reeds on the border of Snape Marshes and Snape Common. Some notable absentees Ena obscura (MĂźller). Although this species is usually very common in most places, after careful search we failed to find it. Vertigo spp. Careful search was also made in the most likely places in the marshes in three of the squares but although we have nine species of this genus on the British list none was found. I

Map showing the 10 km. squares in the County of SufTolk with the numbers of non-marine mollusca recorded for each Square to October, 1968.


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Looking forward T h e present paper is the result of a small number of visits to selected places in the four squares recorded, large parts remain untouched so far as the present census is concerned. It is hoped that this paper will stimulate more research. Again, as will be evident from the map, many of the squares are at present blank. It is not difficult to find twenty species; to record sixty species means considerable work but it should be possible for members of the Society living in areas where no records have been made to do good work towards Alling in the blanks. One is tempted to work areas which promise a good number of species. Scientifically it is just as important, and in some cases more important, to work in habitats unfavourable to mollusca such as Lakenheath Warren. Habitats with an acid soil should not be neglected; ancient woodlands which have been undisturbed for centuaries should have special attention. Although we were disappointed at finding no mollusc in Staverton Thicks this absence of shells and slugs should be checked by local naturalists, and if correct its cause be investigated. Finally, certain areas liable to flooding by the sea, e.g., Aldeburgh Marshes, and other similar localities, should be exhaustively studied and the species found there listed so that, should there be another flood as happened in 1953, its effect on the molluscan fauna can be ascertained.

Acknowledgements I am grateful to Mr. Stratton for his help as mentioned above and also to Dr. Kerney for his careful checking of our determinations and advice in writing this paper. And indeed to Lord Cranbrook for his encouragement and his help in making the collections on which this paper is based.

References Greene, C. (1891). Catalogue of L a n d and Freshwater Mollusca of Suffolk. S u f f . Inst, of Archeol. 7, 275. Morley, C. (1940). T h e Mollusca of Suffolk (by our Conchological members). Trans. S u f f . Nat. Soc. 4(1), 2-22. (Note. I have attributed this paper to Claude Morley on t h e basis of the general style of writing and phrasing so well known to any who knew h i m personally.) Mayfield, A. (1903). Notes on the L a n d and Freshwater Mollusca of East Suffolk. J. Conch. 10, 295-299. Mayfield, A. (1906). Contributions towards a List of West Suffolk N o n marine Mollusca. J. Conch. 11, 333-340.


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Mayfield, A. (1909). 12, 269-282.

T h e Non-marine Mollusca of Suffolk.

J.

Conch.

M u u s , B. J. (1963). Some Danish Hydrobiidae with the description of a new species, Hydrobia neglecta. Proc. Malac. Soc. Land. 35, 131-138.

R e c o m m e n d e d Reading Janus, H . T h e Young Specialist looks at L a n d and Fresh Water Molluscs. Burke Publishing Co. Ltd., 15/-.

A Contribution to the Census of the Non-marine Mollusca of Suffolk  
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