Abstract:To explain the origin of the differentiation of the spring-inhabiting fauna on an island system, this study focused on the Aegean Islands and the Bythinella snails as a model organism. We inferred the phylogeographic pattern of the Aegean Bythinella with two molecular markers, and compared the inferred pattern with the geological history of the region and the estimated levels of biodiversity of Bythinella in Greece. 95 sequences of COI and 60 of ITS-1 were obtained from samples collected from Andros, Crete, Na… Show more
“…The authors of the present paper discovered another Bythinella hotspot in central Greece (Szarowska et al 2015). Thus, all the hotspots occur in mountain areas, which strongly suggests, that this type of landscape is especially favourable for Bythinella .…”
Bythinella is a minute dioecious caenogastropod that inhabits springs in central and southern Europe. In the Balkans, previous studies have addressed its morphological and genetic differentiation within Greece and Romania while the Bulgarian species have remained poorly known. The aim of the present paper has been to expand the knowledge on the subject in Bulgaria. Shell morphology and anatomy of the reproductive organs were examined, and a fragment of the mitochondrial cytochrome oxidase subunit I (COI) gene and the nuclear ribosomal Internal Transcribed Spacer 1 (ITS-1) were sequenced from 15 populations. Additional sequences from eight previously studied populations were included in our analyses. Phylogenetic analyses revealed five main mitochondrial DNA clades, which were partly confirmed by analyses of the ITS-1 sequences. The genetic differentiation between the clades was found to be in the range p=2.4-11.8%. Most of the populations belonged to clade I, representing Bythinella
hansboetersi, and were distributed in SW Bulgaria. Clades II and III inhabit areas adjacent to clade I and were most closely related with the latter clade. Much more distinct were clade V, found at one locality in NW Bulgaria, and clade IV, found at one locality in SE Bulgaria, close to the sea. Four populations were found in caves, but only one of these represented a distinct clade. Considering the observed pattern of interpopulation differentiation of Bythinella in Bulgaria, we can suppose that isolation between clades I, II and III may have been caused by glaciations during the Pleistocene. The time of isolation between the above three clades and clade IV coincides with the Messinian Salinity Crisis, and the time of isolation between the clade V and the other four most probably reflects the isolation of the Rhodopes from western Balkan Mts by the seawater of the Dacic Basin.
“…The authors of the present paper discovered another Bythinella hotspot in central Greece (Szarowska et al 2015). Thus, all the hotspots occur in mountain areas, which strongly suggests, that this type of landscape is especially favourable for Bythinella .…”
Bythinella is a minute dioecious caenogastropod that inhabits springs in central and southern Europe. In the Balkans, previous studies have addressed its morphological and genetic differentiation within Greece and Romania while the Bulgarian species have remained poorly known. The aim of the present paper has been to expand the knowledge on the subject in Bulgaria. Shell morphology and anatomy of the reproductive organs were examined, and a fragment of the mitochondrial cytochrome oxidase subunit I (COI) gene and the nuclear ribosomal Internal Transcribed Spacer 1 (ITS-1) were sequenced from 15 populations. Additional sequences from eight previously studied populations were included in our analyses. Phylogenetic analyses revealed five main mitochondrial DNA clades, which were partly confirmed by analyses of the ITS-1 sequences. The genetic differentiation between the clades was found to be in the range p=2.4-11.8%. Most of the populations belonged to clade I, representing Bythinella
hansboetersi, and were distributed in SW Bulgaria. Clades II and III inhabit areas adjacent to clade I and were most closely related with the latter clade. Much more distinct were clade V, found at one locality in NW Bulgaria, and clade IV, found at one locality in SE Bulgaria, close to the sea. Four populations were found in caves, but only one of these represented a distinct clade. Considering the observed pattern of interpopulation differentiation of Bythinella in Bulgaria, we can suppose that isolation between clades I, II and III may have been caused by glaciations during the Pleistocene. The time of isolation between the above three clades and clade IV coincides with the Messinian Salinity Crisis, and the time of isolation between the clade V and the other four most probably reflects the isolation of the Rhodopes from western Balkan Mts by the seawater of the Dacic Basin.
“…On the other hand, species identification with DNA sequences is always certain, although species boundaries remain disputable, especially with one locus and small divergence. In the case of B. walensae, however, there are two loci, and the p-distances are high (szArowskA et al 2016). …”
Section: Discussionmentioning
confidence: 99%
“…Species boundaries in Bythinella are still unclear, despite hundreds of sequences now available in the GenBank (FAlniowski 1987, 1992, bicHAin et al 2007a, b, szArowskA & FAlniowski 2008, benke et al 2009, FAlniowski & szArowskA 2011, 2012, szArowskA et al 2016. The simple and highly variable morphology is not sufficient even for species determination, thus molecular data are necessary.…”
Section: Discussionmentioning
confidence: 99%
“…Morphological characters within the Truncatelloidea usually lack the states which are unique, or characteristic at least, the ranges of variation are nearly always wide and overlap between the species or even genera (e.g. FAlniowski 1987, szArowskA & FAlniowski 2008, FAlniowski & szArowskA 2011, FAlniowski et al 2012a, szArowskA et al 2016. On the other hand, species identification with DNA sequences is always certain, although species boundaries remain disputable, especially with one locus and small divergence.…”
Section: Discussionmentioning
confidence: 99%
“…Ten sequences of internal transcribed spacer ITS-1, GenBank numbers: KT353614-KT353615 from locality N01 (Aghio Kyriaki), and KT353616-KT353623 from the type locality N02 (Aria Pygi) (szArowskA et al 2016). Diagnosis.…”
A new species of Bythinella: B. walensae is described from Aria spring at Naxos Island, Greece. Cytochrome oxidase subunit I (COI) sequences of mtDNA, as well as internal transcribed spacer (ITS-1) of nuclear ribosomal DNA indicate distinctness of B. walensae. The shell, female reproductive organs and penis are described. The most characteristic of this species are: slender shell, narrow aperture, J-shaped bursa coupled with bulky and spherical receptaculum, and the length ratio of penis arms. Simple anatomy coupled with wide variation ranges overlapping between the species are emphasised.
The subterranean aquatic snails may serve as a model of endemism and isolation vs. migration in subterranean habitats. The aim of the present paper is to verify the hypothesis that subterranean aquatic snails can migrate through diverse subterranean habitats, applying four molecular markers as well as a RAPD technique and shell morphometry. They were used to estimate the differences and gene flow between populations of the hydrobiid subterranean aquatic species Montenegrospeum bogici, collected in the Dinaric karst region. Three molecularly distinct taxonomic units were distinguished. The mOTU B was found at single locality, mOTU C at two, but the mOTU A at ten localities, scattered along 236 km distance, at two of them in sympatry with either mOTU B or C. Within mOTU A, the estimated levels of the gene flow were high. The pairwise measures of genetic differentiation were statistically significantly associated with geographic distances between the populations. In general, neither the infinite-island model of interpopulation differentiation, expected for isolated populations, nor the stepping-stone one, but rather the isolation-by-distance model explained the observed pattern. Our results suggest that interstitial habitats provide ways of migration for the stygobiont M. bogici, as has been already suggested for other subterranean gastropods.
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