Shell shape, dysodont tooth morphology, and hinge-ligament thickness in the bay mussel Mytilus trossulus correlate with wave exposure

2000 ◽  
Vol 78 (2) ◽  
pp. 240-253 ◽  
Author(s):  
Robert J Akester ◽  
André L Martel
Keyword(s):  
Shell Length ◽  
Shell Height ◽  
Wave Exposure ◽  
Shell Morphology ◽  
Shell Shape ◽  
Width Ratio ◽  
Mytilus Trossulus ◽  
Barkley Sound ◽  
High Wave Energy ◽  
Mussel Mytilus Trossulus

We examined the shell morphology of the bay mussel Mytilus trossulus (Gould) at six locations with various levels of wave exposure in Barkley Sound on the west coast of Vancouver Island, British Columbia, Canada. Young adult M. trossulus (29-35 mm shell length) collected from wave-exposed sites displayed striking differences in shell morphology from M. trossulus from sheltered sites. Mytilus trossulus from wave-exposed habitats had a lower shell height / shell width ratio and a thicker shell; they also had higher, more robust dysodont teeth, as well as a thicker hinge ligament. Examination of juveniles (12-14 mm shell length) collected from a wave-exposed shore and a sheltered shore separated by only a few hundred metres displayed similar differences in shell morphology and ligament thickness. These observations suggest that wave exposure is the cause of the observed differences in shell morphology and ligament thickness in M. trossulus. This is the first report of a correlation between wave exposure and morphology of the dysodont teeth and ligament in a bivalve. We discuss potential selective pressures that may favor characteristics of wave-exposed shells, including the probability of dislodgment and misalignment of valves in high wave energy areas.

scholarly journals Spatial distribution and morphometry of the succineid snail Succinea baconi (Pfeiffer, 1854) in India

2021 ◽  
Author(s):  
Himangshu Barman ◽  
Soujita Pramanik ◽  
Gargi Nandy ◽  
Sampa Banerjee ◽  
Gautam Aditya
Keyword(s):  
Spatial Distribution ◽  
Vertical Distribution ◽  
Shell Length ◽  
Land Snail ◽  
Shell Morphology ◽  
Shell Shape ◽  
Regression Equations ◽  
Growth Strategies ◽  
Shell Weight ◽  
Significant Difference

The spatial distribution and morphological features of the land snail Succinea baconi (Pfeiffer, 1854) (Gastropoda: Succineidae) from India were evaluated. The survey performed in gardens and bushes in Coochbehar, West Bengal, India, has made it possible to assess the abundance of the snail S. baconi on the randomly selected lemon plants (n = 18). Logistic regressions were employed to judge differences in vertical distribution, resource association and size class variation in the snails under study. Variation in shell morphology was assessed by performing the regression analysis of the sampled shells of live snails (n = 258) and vacant shells of the deceased individuals (n = 100). An overall significant difference (p < 0.05) in the vertical distribution of snails in lemon plants was observed. As to their association with resources available, snails were found to be more abundant in detritus than on living parts of the plants. The performed logistic regression revealed that the relative abundance of different S. baconi size classes was significantly different (p < 0.001). Significant correlations (p < 0.001) were found among different body size variables, with the shell length (x)-body weight (y) relationship being: y = 0.232x2.524 (for live snails) and the shell length (x)-shell weight (y) relationship being: y = 0.358x2.537 (for shells of dead snails). Various parameters of the snail shell shape could be represented through regression equations. Although reproduction and growth strategies of snails need to be explored further, the presented observations improve our understanding of the ecology of S. baconi, which may prove useful for future conservation efforts.

Evaluation of reproduction for mussel Mytilus trossulus (Bivalvia: Mytilidae) in the Veselaya Bay (Tauiskaya Guba Bay, Okhotsk Sea)

2018 ◽  
Vol 194 ◽  
pp. 175-187 ◽  
Author(s):  
V. S. Zharnikov
Keyword(s):  
Growth Rate ◽  
Shell Length ◽  
Size Composition ◽  
High Water ◽  
Mytilus Trossulus ◽  
Okhotsk Sea ◽  
High Water Temperature ◽  
Spat Collection ◽  
Mussel Mytilus Trossulus ◽  
Larvae Density

Abundance, size composition, and terms of plankton stage were investigated for the larvae of pacific mussel in the Veselaya Bay (Okhotsk Sea) in two years with different oceanographic regime. The first larvae (density 8-30 ind./m³, shell length 75–150 μm) appeared in late June in the year with relatively high water temperature (2016) and in early July in the year with lowered temperature (2011), then their number had increased to 1750 ind./m³ in early August of 2016 and to 1320 ind./m³ in late August of 2011. Density and size composition of the spat and young mussels were examined in hanging collectors and nurseries. The growth rate change in dependence on shell length was noted. There is concluded that the hanging collectors are more effective for spat collection, while the nurseries are better for growing of littoral mussels.  

Factors Influencing Shell Shape in the Mussel Mytilus Edulis

1968 ◽  
Vol 48 (3) ◽  
pp. 561-584 ◽  
Author(s):  
R. Seed
Keyword(s):  
Mytilus Edulis ◽  
Slow Growth ◽  
Shell Height ◽  
Shell Morphology ◽  
Population Variation ◽  
Shell Shape ◽  
Factors Influencing ◽  
High Incidence ◽  
Local Variability ◽  
Transplantation Experiments

An attempt is made to explain the great variations in gross shell morphology noted in field populations of Mytilus edulis.In any one mussel population, variation in shell form can be attributed to differences in age, old mussels having proportionately heavier shells where width often exceeds shell height. This is invariably accompanied by down-turned, divergent umbones and varying degrees of incurvature of the ventral shell margin.Variations in the age structure of mussel populations from different habitats can also account for local variability in shell morphology. Localities where the life expectancy of mussels is increased due to absence of predators (especially in the upper shore) reveal a high incidence of old ‘ungulate’ individuals, whereas populations in which the mussel turnover is more rapid show a preponderance of relatively young mussels.Shell morphology is greatly influenced by growth rate and density. These probably exert their effect through physical compression which is maximum in localities of fast growth and high density and least in areas of slow growth and low density. High compression leads to an elongate form whereas low compression results in higher, more triangular shaped shells. Growth rates and densities, even within the same habitat, are, however, exceedingly variable.Since all environmental conditions vary in both time and space, wide variation in shell morphology is to be expected, even in animals from the same locality.Transplantation experiments indicate that variation in shell morphology is essentially phenotypic, older animals being more likely to exhibit a form which is characteristic of their particular habitat. Smaller mussels from widely different habitats show remarkable similarity in shell morphology.

Trematode-induced alterations in shell shape of the mud snail Zeacumantus subcarinatus (Prosobranchia: Batillariidae)

2005 ◽  
Vol 85 (4) ◽  
pp. 989-992 ◽  
Author(s):  
K.B. Hay ◽  
B.L. Fredensborg ◽  
R. Poulin
Keyword(s):  
Shell Length ◽  
Host Response ◽  
Shell Morphology ◽  
Shell Shape ◽  
Trematode Species ◽  
Double Infection ◽  
Mud Snail ◽  
Species Specific

The shell morphology of mud snails, Zeacumantus subcarinatus, both uninfected and infected by trematodes, was compared to determine if different trematode species induce different degrees of alteration in host shell shape. Snails harbouring either the echinostomatid Acanthoparyphium sp., or a double infection by the microphallid Maritrema novaezealandensis and an undescribed philophthalmid species, had a wider shell base relative to the rest of the shell spire, than uninfected snails or snails infected by only one of the latter two trematode species. These results are independent of any differences in shell length among the different infection groups. The findings of this study suggest that alterations in host shell morphology are species-specific trematode manipulations of host phenotype rather than a generalized host response to castrating trematodes.

An analysis of morphological variation in limpets of the genus Collisella

1978 ◽  
Vol 56 (4) ◽  
pp. 643-650 ◽  
Author(s):  
Paul A. Dehnel
Keyword(s):  
Morphological Variation ◽  
Shell Length ◽  
Shell Height ◽  
Shell Morphology ◽  
Shell Weight ◽  
Shell Width ◽  
Significant Relationships ◽  
Wet Weight ◽  
Animal Growth

Shell morphology, radular length, and wet weight of soft parts were compared between three species (Collisella pelta, Collisella persona, and Collisella scutum) from one geographic locality. Shell length vs. shell height, wet weight of soft parts vs. radular length, and shell length vs. radular length are statistically significant relationships to separate the three species. Shell weight vs. wet weight of soft parts, wet weight of soft parts vs. extravisceral space, and shell volume vs. wet weight of soft parts are statistically significant relationships to separate C. scutum from either C. pelta or C. persona. These comparisons do not separate C. pelta from C. persona. Shell length vs. shell width, shell length vs. shell volume, and shell length vs. shell weight were found not to be statistically significant relationships to separate the three species. The importance of using shell length and wet weight of soft parts as a measure of animal growth is discussed.

scholarly journals Shape and growth in European Atlantic <i>Patella limpets</i> (Gastropoda, Mollusca). Ecological implications for survival

Web Ecology ◽  
2007 ◽  
Vol 7 (1) ◽  
pp. 11-21 ◽  
Author(s):  
J. Paulo Cabral
Keyword(s):  
Shell Growth ◽  
Shell Height ◽  
Relative Size ◽  
Shell Shape ◽  
Width Ratio ◽  
Temperature Stresses ◽  
Ecological Implications ◽  
Low Levels ◽  
Patella Ulyssiponensis ◽  
High Shore

Abstract. Specimens of Patella intermedia, Patella rustica, Patella ulyssiponensis, and Patella vulgata were analyzed for shell and radula characteristics. Shell growth in P. rustica and P. ulyssiponensis was basically isometric, indicating that shell shape was constant during growth. On the contrary, shell growth in P. intermedia and P. vulgata was positively allometric, indicating that as shells increased in size, the base became more circular and the cone more centred and relatively higher. Radula relative size increased in the order P. ulyssiponensis, P. vulgata, P. intermedia and P. rustica, and had negative allometric growth in all species, indicating that radula grew less as shell increased in size. Data reported in the literature estimated that the lowest risk of dislodgment for a limpet is associated with a centred apex, and a (shell height)/(shell length) or (shell height)/(shell width) ratio of ca. 0.53. However, as reported for other limpets, in all four studied Patella species, shells were more eccentric and flat than this theoretical optimum. Data reported in the literature indicated that, in limpets, decreasing the (shell base perimeter)/(shell volume) or (shell surface area)/(shell volume) ratios by increasing size results in lower soft body temperature and desiccation. In the present study, P. rustica shells displayed the lowest ratios, and P. ulyssiponensis shells, the highest. Considering that the former species lives at high shore levels, and the latter species at low levels, it appeared that shell shape in European Atlantic limpets can be directly related to resistance to desiccation and high temperature stresses. Radula relative size (in relation to shell height) also increased with increasing level in the shore, suggesting that this might be due to a decreasing abundance of algae with increasing shore level.

Ecophenotypic plasticity in shell growth direction of asari clam Ruditapes philippinarum

2021 ◽  
pp. 1-6
Author(s):  
Takeshi Tomiyama
Keyword(s):  
Growth Rate ◽  
Shell Growth ◽  
Shell Height ◽  
Growth Direction ◽  
Ruditapes Philippinarum ◽  
Shell Morphology ◽  
Individual Growth ◽  
Shell Size ◽  
Internal Factors ◽  
Suitable Habitats

Abstract Asari clam (or Manila clam) Ruditapes philippinarum is an important bivalve for local fisheries. This species exhibits a large variation in shell morphology, and the shell roundness tends to be greater in more unsuitable habitats. To test whether the increments in shell size parameters (length, height and width) were affected solely by environmental conditions or by internal factors such as initial shell shapes or growth rate, a field caging experiment was conducted at two different sites of unsuitable and suitable habitats in Matsukawaura Lagoon, Japan, where shell shapes of wild clams were significantly different between the habitats. In the experiment, clams were released from the two sites to the same site or to the other site and were re-collected after 3, 6 and 12 months of caging. Caged clams originating from unsuitable habitats and released to suitable habitats showed a reduction in shell height relative to shell length, while clams from suitable habitats introduced to unsuitable habitats showed marked increases in both shell height and width. Generalized linear mixed models suggested that the increase in shell height was affected largely by the release habitat (environment) whereas the increase in shell width was affected largely by the individual growth rate. These results suggest that marginal growths in shell height and width respond differently to external and internal factors of clams, resulting in plasticity in their shell shapes according to the environments to which they are translocated.

scholarly journals Effects of low-pH stress on shell traits of the dove snail, <i>Anachis misera</i>, inhabiting shallow-vent environments off Kueishan Islet, Taiwan

2015 ◽  
Vol 12 (9) ◽  
pp. 2631-2639 ◽  
Author(s):  
Y. J. Chen ◽  
J. Y. Wu ◽  
C. T. A. Chen ◽  
L. L. Liu
Keyword(s):  
Shell Length ◽  
Shell Thickness ◽  
Expression Profiles ◽  
Shell Shape ◽  
Natural Environments ◽  
Additional Information ◽  
Shell Width ◽  
T1 And T2 ◽  
Body Whorl ◽  
Protein Expression Profiles

Abstract. The effects of naturally acidified seawater on shell traits were quantified through the comparison of dove snails (Family: Columbellidae) Anachis misera from vent environments with Euplica sp. from non-vent sites in northeastern Taiwan. Samples of A. misera were collected around a shallow vent (24.8341° N, 121.96191° E), which included the east, south, southwest, and northwest sites. An absence of Anachis snails was found in the most acidic north site (pH 7.19–7.25). Based on the similarities of protein expression profiles, the Anachis snails were classified into two groups, i.e., V-South (pH 7.78–7.82) and V-Rest (pH 7.31–7.83). Comparing their shell traits to the non-vent Euplica sp. from Da-xi (DX) and Geng-fang (GF) (pH 8.1–8.2), a difference in shell shape (shell width : shell length) was found, with the populations having more globular shells than the non-vent ones. The means of shell width were significantly different among sites (p < 0.01), with a descending order of GF > DX > V-South and V-Rest. The relationships of shell length to total weight were curvilinear for both Anachis and Euplica snails. The logarithmically transformed slopes differed significantly among sites, and the mean body weight of the GF population was greater than that of the others (p < 0.01). Positive correlations between shell length and shell thickness of body whorl (T1) and penultimate whorl (T2) were only observed in non-vent GF and DX populations. Anachis snails from vent sites were thinner in T1 and T2 compared to the Euplica snails from non-vent sites (p < 0.05). Within each vent group, shell thickness between T1 and T2 was insignificantly different. Between vent groups, T1 and T2 from V-Rest showed a decrease of 10.6 and 10.2%, respectively, compared to V-South ones. The decrease of T1 and T2 between vent Anachis snails and non-vent Euplica snails was as great as 55.6 and 29.0%, respectively. This was the first study to compare snail's morphological traits under varying shallow-vent stresses with populations previously classified by biochemical responses. Overall, the shallow-vent-based findings provide additional information from subtropics on the effects of acidified seawater on gastropod snails in natural environments.

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