BASTERIA 44: 3-8, 1980 the Pigmentation of the mantle border in Polish representatives of subgenus Radix (Lymnaeidae, Basommatophora, Gastropoda) Andrzej Falniowski Muzeum Zoologiczne, Uniwersytet Jagiellonski, Ul. Mieczyslawa Karasia 6, 30-060 Krakow, Poland While material of the Radix Montfort from various working on a large subgenus parts of Poland, I noticed marked interspecific differences in mantle border pigmentation. of value a number of molluscs Pigmentation characters may be taxonomic in (e.g., Muus, 1967). Roszkowski (1914) when studying specimens from Ruda Maleniecka found small differences mantle between near Warsaw in pigmentation Lymnaea (Radix) auricularia and L. the latter the border (Linne), (R.) peregra (O.F. Miiller); in species free from somewhat wider. Feliksiak showed belt, pigmentation, was (1939) Myxas to characteristic of similar to that glutinosa (O.F. Miiller) possess a pattern pigmentation, which would further for the found by me in L. auricularia, provide a argument similarity of these species. Marked differences in the development of this character in L. auricularia of Lake found Burla and L. peregra the Zurich were by & Speich (1971). In the investigations here presented I included 5,096 specimens from stations of distributed all Poland. Mantle various type, nearly over pigmentation generally displayed often several the but pronounced polymorphism; types were present at same station, In the ofblack had generally the variability was continuous. most cases spots pigment an indented border this even or a slightly (the specimen shown in fig. 5 is atypical in respect) in L. whereas in L. the border indented. The auricularia, pere gra was always strongly degree to which the mantle is covered with black pigmentation shows great individual from of of and the variability, complete absence spots (fig. 6), through spots varying size which cream-coloured rather degree to they are covering the background, to infrequent with the border specimens a completely black mantle except for area. In general, a with somewhat is noted in L. a stronger pigmentation usually peregra; specimens black found this but the completely mantle have been by me to occur in species only, allow for distinction between the variability is so high as not to drawing a species. I can corroborate the data of Roszkowski L. the only partly (1914): in most peregra area without in fact than in deviations this pigment is wider L. auricularia, yet there are from rule. from Lake Slawskie with wide A specimen (fig. 12) an unusually strip without and the the similar pigmentation in remaining part of mantle a pigmentation pattern to 4 BASTERIA, Vol. 44, No. 1-4, 1980 of L. the of that characteristic glutinosa is noteworthy. Perhaps atypical pattern pigmentation in this animal is connected with the fact of it being strongly infected by larvae of trematodes. differences have been found the the Distinct interspecific to occur in development of the border. the pigmentation pattern near mantle As can be seen from figs. 1-19 spots free from disappear at some distance from the border, leaving a belt of varying width, clusters. There when the pigmentation are frequent cases spots next to the border are on covered with less dense a background a more or pigmentation (figs. 3, 8-9, 11, 13-16, this often L. the border of the 18-19), happening more in peregra. On spotless strip mantle of L. there is while in L. auricularia there is peregra usually no pigmentation, marked line of dark in the middle of this belt always a pigmentation approximately worth that such line (figs. 2-11). It is noting a is clearly seen even in quite spotless this specimens (fig. 6). The line under discussion in most cases in species is composed of discernible but then it series clearly dots, being rarely vague (figs. 7-11), even occurs as a of dots the the ventral side of the mantle sharply standing out against background on (fig. 2). I should like to stress that the photographs present all pigmentation types found in even those characteristic of individual hence they do not my material, specimens; adequately reflect the distinct specific character of this feature's development, observed in nearly every case. In L. has the border belt in most cases peregra no pigmentation on (figs. 12-17). Only from the road two specimens of 5,096 examined, an atypical, muddy pond near Bialowieza-Pogorzelce (in the Bialowieza Forest) which also had peculiar shells, I have L. with observed a marked strip of pigmentation, similar to that found in auricularia, but its central border more faded and invisible from the ventral side of the mantle (figs. 18- 19). features the Independently of the described pigmentation in L. peregra background be the darker a could often be may lighter or darker; on background lighter strip with the that the discerned, to a varying extent contrasting background, So general of the border could somehow be likened that foundin L. auricularia. appearance strip to the bursa distinct duct. This happened nearly always in specimens with copulatrix having a differences shown above the of The interspecific in development pigmentation seem to be features and well be that have not been taken good diagnostic one may surprised they t should be in of the with into consideration yet. It emphasized that, spite rare specimens of border well with atypical pigmentation and pronounced variability pigmentation as (yet and the scheme at the discontinuous general intact), any station variability was always of which easily allowed determining the species, even in the case juvenile specimens, would be if different method were be The found not possible a to applied. simultaneously anatomical makes consider the features here described as great variability us pigmentation of which most to one the best diagnostic criteria are, moreover, convenient apply. 5 Falniowski: Mantle border pigmentationin Radix in Poland Figs. 1-6. Habitus and pigmentation of the mantle in Lymnaea (Radix) auricularia from Lake Gardno, Poland. 1. Snail in the shell, dorsal view; 2. Do., ventral view, note the band of black grain-like Mantle in from different pigmentation, which never occurs in L. peregra; 3-6. pigmentation specimens stations in Lake Gardno. 6 BASTERIA, Vol. 44, No. 1-4, 1980 Figs. 7-13. Pigmentation of the mantle in different localities in Poland, figs. 7-11 Lymnaea (Radix) auricularia, 12-13 L. 7-8. Nida River Pińczów; 9-10 Lake 11. Odra River figs. (R.) peregra. near Sarag; near Zielona Gora; 12. Lake Slawskie; 13. Niepolomice Forest (specimen with distinct duct on bursa copulatrix). Falniowski: Mantle border pigmentationin Radix in Poland 7 14-19. of the mantle in in different localities in Poland. Figs. Pigmentation Lymnaea (Radix) peregra ofPuck, Baltic 14. Lake Gardno (specimen with distinct duct on bursa copulatrix); 15. Bay southern Sea Lake (specimen with distinct duct on bursa copulatrix); 16. Gardno; 17. Nida River near Pińczów; duct 18-19. Bialowieża Forest (specimen with distinct on bursa copulatrix). 8 BASTERIA, Vol. 44, No. 1-4, 1980 REFERENCES BURLA, H., & Ch. SPEICH, 1971. Lymnaea auricularia und Lymnaea ovata im Ziirichsee. — Rev. suisse Zool. 78: 549-556. FELIKSIAK, S., 1939. Ueber Biologie und Morphologie der Mantelschnecke, Radix glutinosa (O.F. Miiller). — Zool. Jb. Syst. 72: 17-70. MUUS, B., 1967. The fauna ofDanish estuaries and lagoons. — Meddr. Danra. Fisk. og Havunders. N.S. 5: 1-316. ROSZKOWSKI, W., 1914. Note sur l'appareil genital de Limnaea auricularia L. et Limnaea ovataDrap. -Zool. Anz. 44: 175-179. Samenvatting In Polen auricularia L. elkaar onderscheiden de blijken Lymnaea (Radix) en (R.) peregra van te aan de mantelrand. L. auricularia komt band pigmentatie van Bij een van kleine pigmentvlekjes aan de mantelrand die L. ontbreekt Slechts totaal voor, bij peregra (fig. 2). bij twee exemplaren op een van 5096 van L. werd als auricularia dien peregra een pigmentband bij L. gevonden (fig. 18-19), met ver- stande dat de band wel enigszins afwijkend was. De schelpen van deze dieren waren ook niet geheel L. typisch voor pere gra evenals trouwens de vindplaats. Bij deze soortblijkt een correlatie te bestaan van de de mantelrand ontwikkelde aanwezigheid van een pigmentband op en een goed afvoergang van de bursa copulatrix..