Intraspecific Morphological and Genetic Variability in the European Freshwater Snail Radix Labiata (Rossmaessler, 1835) (Gastropoda: Basommatophora: Lymnaeidae)
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Contributions to Zoology, 82 (1) 55-68 (2013) Intraspecific morphological and genetic variability in the European freshwater snail Radix labiata (Rossmaessler, 1835) (Gastropoda: Basommatophora: Lymnaeidae) Katrin Schniebs1, 4, Peter Glöer2, Maxim V. Vinarski3, Anna K. Hundsdoerfer1 1 Senckenberg Natural History Collections Dresden, Museum of Zoology, Königsbrücker Landstraße 159, D-1109 Dresden, Germany 2 Biodiversity Research Laboratory, Schulstraße 3, D-25491 Hetlingen, Germany 3 Museum of Siberian Aquatic Molluscs, Omsk State Pedagogical University, Tukhachevskogo Emb. 14, 6440099 Omsk, Russian Federation 4 E-mail: [email protected] Key words: molecular genetics, morphology, Radix labiata, variation Abstract Conclusions ...................................................................................... 63 Acknowledgements ........................................................................ 65 References ........................................................................................ 65 Radix labiata is a widely distributed Palaearctic freshwater Appendix .......................................................................................... 67 snail. This work aims to improve the knowledge of the intraspe- cific variability in the most important characters used for its determination. To find out which characters are really suitable to distinguish this species from other similar Radix species an Introduction integrative approach was applied, involving morphological and molecular data.Molecular sequences of the nuclear spacer frag- The pond snail Radix labiata (Rossmaessler, 1835) is a ment ITS-2 and/or the mitochondrial gene fragment cyt-b were obtained from 26 individuals of R. labiata from different re- Palaearctic species that occurs both in lowlands and gions of Europe, including type localities of Limnaeus pereger mountains. In earlier literature this species has com- labiatus. From the subsample of 24 specimens of which se- monly been referred to as ‘Lymnaea peregra’, ‘Radix quences of both gene fragments were available, the variability pereger’, or ‘Radix peregra’. However, the name R. la- of several characters that are commonly used for species identi- biata has been reinstated for the present species by fication (shell morphology, mantle pigmentation, shape and po- sition of the bursa copulatrix, length and position of the bursa Falkner et al. (2001) while the name Buccinum pere- duct, length ratio of praeputium to penial sheath) were meas- grum O. F. Müller 1774 introduced for specimens from ured or documented. Morphological characters distinguishing Copenhagen (Frederiksberg) is considered to be a jun- R. labiata from R. balthica, R. lagotis and the genus Stagnicola ior synonym of Radix balthica (Linnaeus, 1758) accord- are discussed. The best morphological character to differentiate ing to Glöer (2002). these species is the position of the bursa and the bursa duct. Mantle pigmentation and the ratio of the length of the praepu- In Europe R. labiata is distributed from Norway, tium to that of the penial sheath are not useful for differentiat- Sweden and Finland in the north (Falkner et al., 2001; ing R. labiata and R. balthica. Analysis of the network of hap- Welter-Schultes, 2012), to Spain in the west and Italy in lotypes (cyt-b) revealed no correlation between recognisable the south (Welter-Schultes, 2012), Bulgaria in the south- clusters and geography amongst the studied specimens. east (Angelov, 2000; Welter-Schultes, 2012), and the Ukraine in the east (Stadnichenko, 2004; Welter-Schul- tes, 2012). In Asia it is known from Turkey and the Ural Contents Mountains (Khokhutkin et al., 2009) up to the Irtysh River Basin in the east (Kruglov and Starobogatov, Introduction ..................................................................................... 55 1983; Kruglov, 2005; Vinarski et al., 2008). In these Material and methods .................................................................... 56 Molecular techniques .............................................................. 56 Russian sources the species is still mentioned under the Morphology ............................................................................... 57 name Lymnaea (Peregriana) peregra (O.F. Müller, Results ............................................................................................... 57 1774). Molecular genetics .................................................................. 57 Radix labiata prefers small, still or slow-running Morphology ............................................................................... 59 freshwater bodies but also lives in bogs (Glöer, 2002), in Discussion ........................................................................................ 59 Molecular phylogeny ............................................................... 59 springs or water bodies supplied by ground water (Glöer Morphology ................................................................................ 61 and Diercking, 2010), in floodplains (Khokhutkin et al., Downloaded from Brill.com10/04/2021 12:09:08PM via free access 56 Schniebs et al. – Intraspecific variability in EuropeanRadix labiata 2009) and in shallow parts of high-mountain lakes ty of several characters that are commonly used for (Angelov, 2000). In Switzerland this species occurs at determination was calculated for the 24 individuals of altitudes up to 2700 m in small ponds that are free of which both gene fragments were available. ice for only three to four months (Turner et al., 1998). The species has also been observed in temporary wa- ter bodies (Stadnichenko, 2004; Kruglov, 2005; Vinar- Material and methods ski et al., 2008), and in Western Siberia it occurs al- most exclusively in such habitats (Andreeva et al., As type specimens of R. labiata for anatomical and ge- 2010). In lakes and ponds R. labiata is mostly confined netic analyses are not available, our molecular genetic to areas that temporarily fall dry during dry seasons investigations are based on a specimen from the locus (Ward et al., 1996 and own observations). In Sylt (N typicus of Limnaeus pereger labiatus Rossmaessler, Germany) it was found in a puddle fed by ground wa- 1835: Tharandt (Rossmässler, 1835), Saxony (Germany). ter (Reise and Glöer, 2006). This habitat preference for All specimens used for molecular and morphological ground water may explain why this species is rare in examination are listed in the Appendix. Most were col- lowlands and occurs in mountainous regions. lected or donated for this study and stored in the mol- Caron et al. (2007) demonstrated that R. labiata lusc collection of the Senckenberg Natural History Col- may act as an incidental intermediate host of Fasciola lections Dresden, Museum of Zoology (SNSD). Two hepatica; Huňova et al. (2012) successfully infected it samples are stored in the collection of Dr Ulrich Böß- with Fascioloides magna. Thus, reliable identification neck (Vieselbach, Germany). is important not only for malacologists working on For outgroup comparison in the molecular genetic faunistics and zoogeography but also for parasitolo- analyses we used sequences of specimens of other gists. Because morphological and anatomical examina- freshwater molluscs. The outgroup comprised Planor- tion is still the fastest method of determination, even in barius corneus (Linnaeus, 1758), family Planorbidae. the era of molecular genetics – a method not yet acces- We also included sequences of Lymnaea stagnalis (Lin- sible to all malacologists – we consider the study of naeus, 1758), R. auricularia (Linnaeus, 1758), R. ampla intraspecific variability to be very important in order to (Hartmann, 1821), Radix balthica, and R. lagotis improve the reliability of determination keys. As al- (Schrank, 1803) in the ingroup. ready established, the shell of R. labiata is relatively conserved in its shape (Glöer, 2002; Andreeva et al., Molecular techniques 2010) and does not vary as considerably as in R. balth- ica (Schniebs et al., 2011). However, during morpho- Tissue samples taken from the foot were fixed in 100% logical examinations we found specimens differing in ethanol. All these were registered in the tissue collec- characters, such as mantle pigmentation, length of the tion of the SNSD with both a new collection number bursa duct and length ratio of praeputium to penial and the collection number of the specimen in the mol- sheath from what has been described in literature. The lusc collection of SNSD and stored at -80°C. amount of morphological variation found in the present For molecular genetic analyses we obtained se- study raised doubts whether some of the studied speci- quence data of the complete nuclear ITS-2 spacer (280- mens really belonged to this taxon. The present work 495 bp) and a 361 bp fragment of the cyt-b gene as mi- continues our analyses of intraspecific variability that tochondrial marker. For primers and protocols of DNA we started with R. balthica (Schniebs et al., 2011). extraction, Polymerase Chain Reaction (PCR), purifica- To analyse the variability of the most important tion of PCR products and DNA sequencing see Vinar- distinguishing characters of R. labiata (shell mor- ski et al. (2011). Alignments were performed using the phology, mantle pigmentation, shape and position of sequence alignment editor BioEdit (Hall, 1999). The the bursa copulatrix, length and position of the bursa ITS-2 alignment was obtained using the Clustal algo- duct, and length ratio of praeputium to penial