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FIGURE 21 in Adding the West-African riverine component: Revision of the Recent freshwater snails belonging to Pseudocleopatra Thiele, 1928 (Caenogastropoda, Cerithioidea, Paludomidae)

FIGURE 21. Known occurrence records of Pseudocleopatra broecki (Putzeys, 1899) n. comb. in the Congo River system. Asterisks indicate type localities; 1: type locality of Cleopatra broecki Putzeys, 1899 and Cleopatra broecki var. zonata Putzeys, 1899; 2: type locality of Pseudocleopatra bennikei Mandahl-Barth, 1974. The arrow indicates the approximate location of the Inga dams.

FIGURE 10 in Adding the West-African riverine component: Revision of the Recent freshwater snails belonging to Pseudocleopatra Thiele, 1928 (Caenogastropoda, Cerithioidea, Paludomidae)

FIGURE 10. Known occurrence records of Pseudocleopatra togoensis Thiele, 1928 in the Volta River system. The asterisk indicates the type locality. The arrow indicates the approximate location of the Akosombo dam.

FIGURE 9 in Adding the West-African riverine component: Revision of the Recent freshwater snails belonging to Pseudocleopatra Thiele, 1928 (Caenogastropoda, Cerithioidea, Paludomidae)

FIGURE 9. Radula of Pseudocleopatra togoensis Thiele, 1928, Ghana, NE region, DBL 214. A. Radula ribbon; scale bar: 20 μm. B. Lateral and central teeth; scale bar: 10 μm. C. Cutting edge of lateral and central teeth; scale bar: 2 μm. D. Central, lateral and marginal teeth; scale bar: 20 μm.

FIGURE 8 in Adding the West-African riverine component: Revision of the Recent freshwater snails belonging to Pseudocleopatra Thiele, 1928 (Caenogastropoda, Cerithioidea, Paludomidae)

FIGURE 8. Opercula of Pseudocleopatra Thiele, 1928 species. A. Lectotype of P. togoensis Thiele, 1928, ZMB 190048b. B. Paratype of Pseudocleopatra voltana Mandahl-Barth, 1973, Mogeyenga village, DBL 2591. C. Probable paratype of Pseudocleopatra dartevellei Mandahl-Barth, 1973, Matadi, DBL 2583. D. Pseudocleopatra broecki (Putzeys, 1899) n. comb., MCZ 171520. E. Lectotype of Pseudocleopatra broecki (Putzeys, 1899) n. comb., MRAC 47360. Scale bar: 1mm.

FIGURE 7 in Adding the West-African riverine component: Revision of the Recent freshwater snails belonging to Pseudocleopatra Thiele, 1928 (Caenogastropoda, Cerithioidea, Paludomidae)

FIGURE 7. Shells of Pseudocleopatra togoensis Thiele, 1928. A. Lectotype, ZMB 190048a. B. Oti River at Bdakune village, DBL 2601. C. NE-Ghana, DBL 214. D. White Volta River, DBL 12761. Scale bar: 5 mm.

FIGURE 16 in Adding the West-African riverine component: Revision of the Recent freshwater snails belonging to Pseudocleopatra Thiele, 1928 (Caenogastropoda, Cerithioidea, Paludomidae)

FIGURE 16. Radula of Pseudocleopatra dartevellei Mandahl-Barth, 1973 (Morph a), probable paratype, Île des Princes, MRAC 146342. A. Radula ribbon, scale bar: 10 μm. B. Lateral and central teeth, scale bar: 10 μm. C. Cutting edge of lateral and central teeth, scale bar: 10 μm. D. Central, lateral and marginal teeth, scale bar: 10 μm.

FIGURE 6 in Adding the West-African riverine component: Revision of the Recent freshwater snails belonging to Pseudocleopatra Thiele, 1928 (Caenogastropoda, Cerithioidea, Paludomidae)

FIGURE 6. Total variance of examined shell shapes and results of geometric morphometrics analyses of Pseudocleopatra Thiele, 1928 species and Cleopatra bulimoides (Olivier, 1804). A. Relative variance of shell shape along PC1 and PC2. The colours of dots imply species affiliations. Depicted thin plate splines represent shell shapes of individuals with the highest and lowest value along PC1. B, F. Variance of shell shapes of PC1 (B) and PC2 (F). Arrow heads indicate the maximum value on the respective shape axis, whereas grey dots indicate the minimum value. C, E. Boxplots for PC1 (C) and PC2 (E) of shell shape sorted according to species. Significant differences (p <0.05) are indicated by bars. D. Total variance of landmark positions; grey dots correspond to all positions of all landmark sets; black dots indicate the mean position of each landmark across the complete data set.

FIGURE 4 in Adding the West-African riverine component: Revision of the Recent freshwater snails belonging to Pseudocleopatra Thiele, 1928 (Caenogastropoda, Cerithioidea, Paludomidae)

FIGURE 4. Multivariate ratio analysis of shell measurements of Pseudocleopatra togoensis Thiele, 1928, P. voltana Mandahl- Barth, 1973, P. dartevellei Mandahl-Barth, 1973 and P. broecki (Putzeys, 1899) n. comb. A. Plot of isometric size vs. first principal component in shape space. B. Plot of isometric size vs. second principal component in shape space. C. Plot of isometric size vs. third principal component in shape space. D. Plot of first vs. second principal component in shape space. E. Plot of first vs. third principal component in shape space. F. Plot of second vs. third principal component in shape space. G. PCA ratio spectrum of the first principal component. H. PCA ratio spectrum of the second principal component in shape space. I. PCA ratio spectrum of the third principal component in shape space. J. Allometry ratio spectrum. Vertical bars in G–I = 68% confidence intervals based on 500 bootstrap replicates. For abbreviations of measured shell variables, see Fig. 2.

FIGURE 2 in Adding the West-African riverine component: Revision of the Recent freshwater snails belonging to Pseudocleopatra Thiele, 1928 (Caenogastropoda, Cerithioidea, Paludomidae)

FIGURE 2. Shell measurements and positions of landmarks and sliding landmarks. A. Shell measurements of the adult shell. Abbreviations: h—shell height, w—shell width, bw—last whorl height, la—aperture height, wa—aperture width. B. Dots indicate positions of landmarks, lines indicate lines of sliding landmarks (colours indicate different total numbers of sliding landmarks).

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Data from: Characterising a hybrid zone between a cryptic species pair of freshwater snails

Characterising hybrid zones and their dynamics is a central goal in evolutionary biology, but this is particularly challenging for morphologically cryptic species. The lack of conspicuous divergence between parental types means intermediate hybrid forms often go undetected. We aimed to detect and characterise a suspected hybrid zone between a pair of morphologically cryptic lineages of the freshwater snail, Radix. We sampled Radix from across a contact zone between two mitochondrial lineages (Radix balthica and an undescribed lineage termed MOTU3) and detected admixture between two nuclear genotype clusters, which were significantly but not categorically associated with the mitochondrial lineages. In a model selection approach, we show that the admixture cline is best explained by an interaction between precipitation and temperature gradients over the area, rather than geographic distance. We thus hypothesise that the correlation with climatic gradients suggests environmental selection has played a role in maintaining the hybrid zone. In a 2050 climate change scenario, we furthermore predict an expansion of one of the nuclear clusters and a widening of the hybrid zone as the climate warms and dries.

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Data from: Clonal diversity driven by parasitism in a freshwater snail

One explanation for the widespread abundance of sexual reproduction is the advantage that genetically diverse sexual lineages have under strong pressure from virulent coevolving parasites. Such parasites are believed to track common asexual host genotypes, resulting in negative frequency-dependent selection that counterbalances the population growth-rate advantage of asexuals in comparison with sexuals. In the face of genetically diverse asexual lineages, this advantage of sexual reproduction might be eroded, and instead sexual populations would be replaced by diverse assemblages of clonal lineages. We investigated whether parasite-mediated selection promotes clonal diversity in 22 natural populations of the freshwater snail Melanoides tuberculata. We found that infection prevalence explains the observed variation in the clonal diversity of M. tuberculata populations, while no such relationship was found between infection prevalence and male frequency. Clonal diversity and male frequency were independent of snail population density. Incorporating ecological factors such as presence/absence of fish, habitat geography and habitat type did not improve the predictive power of regression models. Approximately 11% of the clonal snail genotypes were shared among 2-4 populations, creating a web of 17 interconnected populations. Taken together, our study suggests that parasite-mediated selection coupled with host dispersal ecology promotes clonal diversity. This, in return, may erode the advantage of sexual reproduction in M. tuberculata populations.

opencc-zeroDec 2012View details →

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Data from: Responses of four submerged macrophytes to freshwater snail density (Radix swinhoei) under clear-water conditions: a mesocosm study

Macrophytes play a key role in stabilizing clear-water conditions in shallow freshwater ecosystems. Their populations are maintained by a balance between plant grazing and plant growth. As a freshwater snail commonly found in shallow lakes, Radix swinhoei can affect the growth of submerged macrophytes by removing epiphyton from the surface of aquatic plants and by grazing directly on macrophyte organs. Thus, we conducted a long-term (11-month) experiment to explore the effects of snail density on macrophytes with distinctive structures in an out-door clear-water mesocosm system (with relatively low total nitrogen (TN, 0.66 ± 0.27 mg L-1) and total phosphorus (TP, 36 ± 20 μg L-1) and a phytoplankton chlorophyll a (Chla) range of 14.8 ± 4.9 μg L-1) based on two different snail densities (low and high) and four macrophyte species treatments (Myriophyllum spicatum, Potamogeton wrightii, P. crispus, and P. oxyphyllus). In the high-density treatment, snail biomass and abundance (36.5 ± 16.5 g m-2 and 169 ± 92 ind m-2, respectively) were approximately twice that observed in the low-density treatment, resulting in lower total and aboveground biomass and ramet number in the macrophytes. In addition, plant height and plant volume inhabited (PVI) showed species-specific responses to snail densities, i.e., the height of P. oxyphyllus and PVI of M. spicatum were both higher under low-density treatment. Thus, compared to low-density treatment, the inhibitory effects of long-term high snail density on macrophytes by direct feeding may be greater than the positive effects resulting from epiphyton clearance when under clear-water conditions with low epiphyton biomass. Thus, under clear-water conditions, the growth and community composition of submerged macrophytes could be potentially modified by the manual addition of invertebrates (i.e., snails) to lakes if the inhibitory effects from predatory fish are minor.

opencc-zeroJun 2021View details →

opennotspecifiedMay 2008View details →

Figure 1 in Protozoan ciliate epibionts on the freshwater apple snail Pomacea figulina (Spix, 1827) (Gastropoda, Ampullariidae) in an urban stream of south-east Brazil

Figure 1 (continued). In vivo photomicrographic images of epibiont ciliates on Pomacea figulina. (K–M). Carchesium polypinum. (N). Colony of Carchesium polypinum as basibiont of the suctorian Tokophrya fasciculata (arrows). (O). Superior view of the suctorian Tokophrya fasciculata. (P–Q). Tokophrya fasciculata. Scale bars: 100 mm.

opennotspecifiedMay 2008View details →

Figure 1 in Protozoan ciliate epibionts on the freshwater apple snail Pomacea figulina (Spix, 1827) (Gastropoda, Ampullariidae) in an urban stream of south-east Brazil

Figure 1. In vivo photomicrographic images of epibiont ciliates on Pomacea figulina. (A–B). Vorticella campanula. (C–D). Epistylis plicatilis. (E–F). Opercularia sp. (G). Vorticella microstoma-complex. (H–J). Epistylis sp. The arrows show the asexual reproduction. Scale bars: 50 mm.

Figure 16 in A unique radiation of marine littorinid snails in the freshwater streams of the Western Ghats of India: the genus Cremnoconchus W.T. Blanford, 1869 (Gastropoda: Littorinidae)

Figure 16. Radula (A, B) and protoconchs (C–F) of Cremnoconchus species. A, B, C. dwarakii (two views of radula, flat and at 45°), Hulikal Ghat, Udupi Dist., Karnataka (shell H = 6.4 mm). C, C. syhadrensis, Matheran, Raigad Dist., Maharashtra. D, C. canaliculatus, 10 km west of Mahabaleshwar, Raigad Dist., Maharashtra. E, C. agumbensis, Agumbe, Udupi Dist., Karnataka. F, C. dwarakii, Hulikal Ghat, Udupi Dist., Karnataka. Scale bars A, B = 50 Mm; C–F = 0.5 mm. White arrowhead marks junction of protoconch and teleoconch.

Figure 13 in A unique radiation of marine littorinid snails in the freshwater streams of the Western Ghats of India: the genus Cremnoconchus W.T. Blanford, 1869 (Gastropoda: Littorinidae)

Figure 13. Radulae of Cremnoconchus species (two views of each radula, flat and at 45°). A, B, C. globulus, Lesser Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H = 7.4 mm). C, D, C. agumbensis, Agumbe, Udupi Dist., Karnataka (ZSI/WGRS; shell H = 9.5 mm). E, F, C. cingulatus, Hulikal Ghat, Udupi Dist., Karnataka (ZSI/WGRS; shell H = 5.7 mm). G, H, C. castanea, Arasinagundi Falls, Udupi Dist., Karnataka (ZSI/WGRS; shell H = 8.5 mm). Scale bars = 50 Mm.

Figure 12 in A unique radiation of marine littorinid snails in the freshwater streams of the Western Ghats of India: the genus Cremnoconchus W.T. Blanford, 1869 (Gastropoda: Littorinidae)

Figure 12. Anatomy of Cremnoconchus hanumani (A–G) and C. globulus (H–L), all to same magnification. A–L, penes (all fixed in ethanol); F, G are intact and sectioned views of same penis. A–C, Hanuman Gundi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H: A = 4.9 mm; B = 3.5 mm; C = 3.3 mm). D–G, Greater Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H: D = 3.9 mm; E = 4.0 mm; F, G = 5.0 mm). H–K, Lesser Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H: H = 7.0 mm; I = 6.0 mm; J = 7.0 mm; K = 6.3 mm). L, Greater Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H = 7.9 mm). Shading conventions as in Figure 6.

Figure 8 in A unique radiation of marine littorinid snails in the freshwater streams of the Western Ghats of India: the genus Cremnoconchus W.T. Blanford, 1869 (Gastropoda: Littorinidae)

Figure 8. Distribution of Cremnoconchus species (solid circles). Two or more species names (e.g. syhadrensis + canaliculatus) indicate sympatric occurrence. See Supporting Table S1 for locality details. The shaded area is the Western Ghats region as defined by Irfan-Ullah & Davande (2008). Cities indicated by asterisks.

Figure 7 in A unique radiation of marine littorinid snails in the freshwater streams of the Western Ghats of India: the genus Cremnoconchus W.T. Blanford, 1869 (Gastropoda: Littorinidae)

Figure 7. Radulae of Cremnoconchus species (two views of each radula, flat and at 45°). A, B, C. syhadrensis, Matheran, Raigad Dist., Maharashtra (ZSI/WGRS; shell H = 7.0 mm). C, D, C. conicus, 6 km west of Mahabaleshwar, Satara Dist., Maharashtra (ZSI/WGRS; shell H = 4.9 mm). E, F, C. canaliculatus, 10 km west of Mahabaleshwar, Raigad Dist., Maharashtra (ZSI/WGRS; shell H = 9.3 mm). G, H, C. hanumani, Greater Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H = 5.0 mm). Scale bars = 50 Mm.

Figure 3 in A unique radiation of marine littorinid snails in the freshwater streams of the Western Ghats of India: the genus Cremnoconchus W.T. Blanford, 1869 (Gastropoda: Littorinidae)

Figure 3. Shells of Cremnoconchus syhadrensis. A, Cremnobates syhadrensis W.T. Blanford, 1863, neotype, no locality (BMNH 1906.1.1.2247). B, C, Matheran, Raigad Dist., Maharashtra (two views of same specimen; ZSI/WGRS/IR.INV- 2290). D, E, Anjani, Nashik Dist., Maharashtra (BMNH 1911.8.23.70–71). F, J–L, Torna Fort, Pune Dist., Maharashtra (USNM 317696). G–I, Khandala, Pune Dist., Maharashtra (G, H two views of same specimen; ZSI/WGRS/IR.INV-2293, 2292). M, Torna Fort, Pune Dist., Maharashtra (USNM 317695).