Ecologica Montenegrina 41: 84-90 (2021) This journal is available online at: www.biotaxa.org/em http://dx.doi.org/10.37828/em.2021.41.12 Pseudobithynia ambrakis Glöer, Falniowski & Pešić 2010 (Gastropoda: Rissooidea: Bithyniidae), a new species from the Macedonian part of Dojran Lake VALENTINA SLAVEVSKA - STAMENKOVIĆ1*, PETER GLÖER2, JELENA HINIĆ1, DANIJELA MITIĆ - KOPANJA1 & VLADIMIR PEŠIĆ3 1Institute of Biology, Faculty of Natural Science and Mathematics, Ss. Cyril and Methodius University, Republic of North Macedonia. E-mails: [email protected]; [email protected]; [email protected] 2Biodiversity Research Lab, Schulstr.3, D25491 Hetlingen, Germany. E-mail: [email protected] 3Department of Biology, University of Montenegro, Cetinjski put b.b 81000 Podgorica, Montenegro. E-mail: [email protected] *Corresponding author: [email protected] Received 1 March 2021 │ Accepted by V. Pešić: 26 April 2021 │ Published online 27 April 2021. Abstract The recently described freshwater gastropod Pseudobithynia ambrakis Glöer, Falniowski & Pešić 2010 is reported from the R. North Macedonia for the first time. The species was previously known only from Lake Amvrakia in Greece, but it turned out to be present in Dojran Lake as well, only misidentified and recognized under different name, Bithynia leachii (Sheppard, 1823). In the following paper we present information about the species’ habitat and distribution. Photographs of the shell and male genitalia are also provided. Key words: Pseudobithynia ambrakis, first record, Dojran Lake, Republic of North Macedonia. Introduction Family Bithyniidae Gray, 1857 (Gastropoda) presents one of the most challenging groups of invertebrates that caught the attention of many malacologists over the last decades (Chung 1984; Kim 2005; Glöer et al. 2007; Glöer et al. 2010; Kulsantiwong et al. 2013; Serbina 2013). Since the family is known for its great diversity (Glöer et al. 2010; Ponder 2003), new species have constantly been recorded and described (Glöer & Yildirim 2006; Glöer & Naser 2008; Brinesh & Janardanan 2009; Glöer & Massen 2009; Glöer & Pešić 2009; Glöer & Georgiev 2012; Glöer et al. 2015; Odabaşı et al. 2013; Odabaşı & Arslan 2015). Recently, Glöer & Pešić (2006) introduced a new genus Pseudobithynia. The highest species richness of the Bithyniidae can be found in Greece with seven Bithynia and nine Pseudobithynia species (Glöer et al. 2010). From Bulgaria only two Bithynia spp. are known, i.e. Bithynia tentaculata (Linnaeaus, 1758) and B. danubialis Glöer & Georgiev, 2012 (Georgiev & Hubenov 2013), in addition to an uncertain record of Bithynia leachi (Angelov 2000). From Serbia B. tentaculata is known, in addition to uncertain records of B. Ecologica Montenegrina, 41, 2021, 84-90 SLAVEVSKA-STAMENKOVIĆ ET AL. leachii (Sheppard, 1823) and the two species Bithynia schwabii (Frauenfeld, 1865), and Bithynia walderdorffii (Frauenfeld, 1865), both of unclear taxonomical status (Bank 2011). From Montenegro four Bithynia spp. are known (Glöer & Pešić 2007, Pešić & Glöer 2013) and from Albania only B. tentaculata and Bithynia radomani have been mentioned (Dhora & Welter-Schultes 1996; Feher & Eross 2009). However, some authors (Feher & Eross 2009) discussed that the record of B. tentaculata most likely refers to B. radomani meaning that there is probably only one Bithynia species in Albania. The family is present also in R. North Macedonia with only two representatives, Bithynia prespensis Hadžišče, 1963 and B. shapkarevi Glöer, Shoreva & Slavevska-Stamenković, 2015 reported from Prespa Lake (Glöer et al. 2015). This paper provides new additions to the freshwater gastropod fauna of R. North Macedonia. We present the first record of the recently described Pseudobithynia ambrakis Glöer, Falniowski & Pešić 2010 in the Macedonian part of Dojran Lake, giving comments on the species distribution, conservation asspects and habitat preferences of the species. Materials and methods Study area Dojran Lake is a trans-boundary lake shared between Republic of North Macedonia and Greece where the Macedonian part of this lake has a surface of 27.3 km2 and 15,8 km2 belong to the Greek part (Stojanov et al. 2003). It is a tectonic lake situated in the Balkan Peninsula at 148 m a.s.l. The watershed of the lake belongs to the river basin of river Vardar that gravitates towards Aegean Sea (Popovska et al. 2005). The Lake was created in the neogen-quarterian period and has a tectonic-volcanic origin (Stojanov 2002). According to the latter author, it is a relict remnant of the former Pleistocene Peon lake, which occupied an area of about 127 km2. Figure 1. Map of the study area and the sampling sites on Dojran Lake (T: Toplec; K: Kaldrma). Data sampling and processing During field trip in 2016, littoral region of the Macedonian part of the Dojran Lake was investigated for the occurrence of freshwater molluscs. The biological material was collected from two sampling sites: Toplec and Kaldrma (Figure 1). Details on the sampling sites are presented in Table 1. The samples were taken with Kick-net from 0.5 to 1 meter depth and then preserved in 75% ethanol. The specimens of Pseudobithynia ambrakis were collected from soft sediment on the sampling locality Toplec where rich plant community of Ecologica Montenegrina, 41, 2021, 84-90 85 PSEUDOBITHYNIA AMBRAKIS FROM THE MACEDONIAN PART OF DOJRAN LAKE macrophytes is encountered (Figure 1 and Figure 2a). The species was also recorded on solid sand and gravel bottom on the sampling site Kaldrma (Figure 1 and Figure 2b). Table 1. Sampling localities where specimens of P. ambrakis were detected. Locality GPS Substrate Date Dojran Lake (near Toplec) 41.235788, 22.718025 Macrophytes 13.08.2016 Dojran Lake (near Kaldrma) 41.214137, 22.709934 Sand and gravel 13.08.2016 Further processing of the collected materials was conducted in the Laboratory of Invertebrates at the Institute of Biology, Faculty of Natural Science and Mathematics in Skopje. All specimens were identified using Nikon SMZ 745 stereomicroscope and deposited in the Macedonian National Collection of Invertebrates (MNCI). Confirmation of the taxonomical identification was conducted by Peter Glöer. Figure 2. Photos of the localities where Pseudobithynia ambrakis was collected: a) Toplec and b) Kaldrma. Photos by V. S. Stamenković. 86 SLAVEVSKA-STAMENKOVIĆ ET AL. Results and discussion The results presented in this paper summarise the recent findings of live individuals of Pseudobithynia ambrakis in Dojran Lake (near Toplec and Kaldrma). These findings presented here are not only the first record of the species in R. North Macedonia, but also the first record of the genus Pseudobithynia in the country. Until now, there were no indications that this species inhabits Dojran Lake, since it was previously reported as Bithynia leachii (Sheppard, 1823) (Stanković 1985) and this data have shown to be misidentification. Namely, B. leachii isn’t distributed in the Balkans, nor the Mediterranean region as published by Welter-Schultes (2012). The latter species is known the lowlands of Northern and Central Europe (Glöer 2019) to Western France to the south (Falkner et al. 2002). Having in mind the similarities between the shells of the Bithynia and Pseudobithynia, errors in the taxonomical identification is expected to occur. The genus Pseudobithynia is relatively new taxon established by Glöer & Pešić (2006) when the authors noticed that some topotypes of “Bithynia” leachii var. graeca had no penial appendix (Figure 3). Figure 3. Pseudobithynia ambrakis. 1: adult specimen shell; 2: juvenile specimen shell; 3: head. Abbreviations: e: eye, p: penis, s: snout, t: tentacle. Photos by P. Glöer. Pseudobithynia ambrakis presents Balkan endemic species known from its type locality, Lake Amvrakia in Greece and now, from Dojran Lake in R. of North Macedonia. It is listed as Vulnerable (VU D2) on the IUCN Red List of Threatened Species based on data about Lake Amvrakia in Greece (Cuttelod et al. 2011). Back in 2017 it was added to the list of species that trigger the criterion for identifying key biodiversity areas (KBA) prepared by Darwall et al. (2014). The change in the Dojran Lake surface balance due to continuous irrigation of the surrounding fields (Manley et al. 2008; Popovska & Bonacci 2008) has been proven to show a negative impact towards the conservation important species (Griffith et al. 2000). This results in degradation of the littoral ecosystem, especially in its northern parts. The eutrophication of the littoral zones is a consequence of their loading with fertilizers and pesticides from the surrounding cultivated fields which provides high eutrophication levels in the whole lake, detected in many investigations such as Tasevska et al. (2010; 2012) and Krstić & Aleksovski (2016). This issue may be a serious threat to the P. ambrakis populations especially because starting from 1988 and due to unfavourable climate conditions and negative anthropogenic impact, the water level in the Lake began to decline rapidly, by which Dojran Lake was subject of hydrological agony (Stojanovski & Krstić 1995). Despite P. ambrakis, the consequences impacted the populations of many other species as well. Namely, the palaeoecology and conservation study conducted on Dojran Lake by Griffith et al. (2002) showed that the status of much of the lake’s endemic life remains problematic. This specifically applies to the Balkan endemic freshwater snail Graecoanatolica macedonica Radoman & Stankovic, 1978 whose live individuals haven’t been detected