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.

scholarly journals Prediction of body weight using morphometric indices in giant African land snail in three zones of Imo state

2021 ◽  
Vol 47 (6) ◽  
pp. 1-9
Author(s):  
S. I. Ahamba ◽  
C. U. Ekugba ◽  
O. E. Kadurumba ◽  
U. E. Ogundu
Keyword(s):  
Body Weight ◽  
Shell Length ◽  
Land Snail ◽  
Study Data ◽  
Shell Weight ◽  
Ecological Zones ◽  
Imo State ◽  
Shell Width ◽  
Poids Corporel ◽  
Significant Difference

Prediction of body weight using morphometric indices in giant African land snail (Achatina marginata) was studied for the three (3) agro-ecological zones in Imo State (Owerri, Okigwe and Orlu zones). One hundred and sixty (160) snails in Imo State were surveyed in course of this study. Data were generated through measurement of body weight, shell length, shell width, shell thickness, mouth length, weight of shell, weight of visceral, length of foot and thickness of foot. Data collected were subjected to regression analysis using SPSS statistical package. Results showed generally highly significant value (P<0.01) R2 value and R-value across the zoness. Highly significant difference (P<0.01) was observed in Owerri zone for the weight of shell, and the shell length. In Okigwe zone, only the weight of visceral showed a significant effect (P<0.01), whereas, in Orlu zone also, the shell width, shell mouth length and foot thickness showed a significant effect (P<0.01). The study therefore recommends that the linear model used, fits the data. Hence a comprehensive selection program for improvement of A. marginata in Imo State could be planned using the regressions coefficients obtained from the study.   La prédiction du poids corporel à l'aide d'indices morphométriques chez l'escargot terrestre géant africain (Achatina marginata) a été étudiée pour les trois (3) zones agro-écologiques de l'État d'Imo (zones Owerri, Okigwe et Orlu). Cent soixante (160) escargots de l'État d'Imo ont été étudiés au cours de cette étude. Les données ont été générées en mesurant le poids corporel, la longueur de la coquille, la largeur de la coquille, l'épaisseur de la coquille, la longueur de la bouche, le poids de la coquille, le poids du viscéral, la longueur du pied et l'épaisseur du pied. Les données collectées ont été soumises à une analyse de régression à l'aide du progiciel statistique SPSS. Les résultats ont montré une valeur R2 et une valeur R généralement très significatives (P <0,01) dans les zones. Une différence très significative (P <0,01) a été observée dans la zone d'Owerri pour le poids de la coquille et la longueur de la coquille. Dans la zone Okigwe, seul le poids des viscéraux a montré un effet significatif (P<0,01), alors que, dans la zone Orlu, la largeur de la coque, la longueur de la bouche de la coque et l'épaisseur du pied ont également montré un effet significatif (P <0,01) que le modèle linéaire utilisé, ajuste les données. Par conséquent, un programme de sélection complet pour l'amélioration d'A. Marginata dans l'État de l'Imo pourrait être planifié en utilisant les coefficients de régression obtenus à partir de l'étude.

Geographical variation in shell morphology of juvenile snails (Concholepas concholepas) along the physical–chemical gradient of the Chilean coast

2013 ◽  
Vol 93 (8) ◽  
pp. 2167-2176 ◽  
Author(s):  
Laura Ramajo ◽  
Ángel Baltanás ◽  
Rodrigo Torres ◽  
Patricio H. Manríquez ◽  
Alejandro Rodriguez-Navarro ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Environmental Gradients ◽  
Function Analysis ◽  
Shell Morphology ◽  
Shell Shape ◽  
Phenotypic Traits ◽  
Shell Weight ◽  
Chilean Coast ◽  
Physical Chemical ◽  
Concholepas Concholepas

Changes in phenotypic traits, such as mollusc shells, are indicative of variations in selective pressure along environmental gradients. Recently, increased sea surface temperature (SST) and ocean acidification (OA) due to increased levels of carbon dioxide in the seawater have been described as selective agents that may affect the biological processes underlying shell formation in calcifying marine organisms. The benthic snailConcholepas concholepas(Muricidae) is widely distributed along the Chilean coast, and so is naturally exposed to a strong physical–chemical latitudinal gradient. In this study, based on elliptical Fourier analysis, we assess changes in shell morphology (outlines analysis) in juvenileC. concholepascollected at northern (23°S), central (33°S) and southern (39°S) locations off the Chilean coast. Shell morphology of individuals collected in northern and central regions correspond to extreme morphotypes, which is in agreement with both the observed regional differences in the shell apex outlines, the high reclassification success of individuals (discriminant function analysis) collected in these regions, and the scaling relationship in shell weight variability among regions. However, these extreme morphotypes showed similar patterns of mineralization of calcium carbonate forms (calcite and aragonite). Geographical variability in shell shape ofC. concholepasdescribed by discriminant functions was partially explained by environmental variables (pCO2, SST). This suggests the influence of corrosive waters, such as upwelling and freshwaters penetrating into the coastal ocean, upon spatial variation in shell morphology. Changes in the proportion of calcium carbonate forms precipitated byC. concholepasacross their shells and its susceptibility to corrosive coastal waters are discussed.

Morphometric relationships and relative growth of Hexaplex trunculus and Bolinus brandaris (Gastropoda: Muricidae) from the Ria Formosa lagoon (southern Portugal)

2015 ◽  
Vol 96 (7) ◽  
pp. 1417-1425 ◽  
Author(s):  
Paulo Vasconcelos ◽  
Carlos M. Barroso ◽  
Miguel B. Gaspar
Keyword(s):  
Shell Length ◽  
Morphological Plasticity ◽  
Shell Shape ◽  
Shell Weight ◽  
Geometric Morphometric ◽  
Relative Growth ◽  
Ria Formosa ◽  
Hexaplex Trunculus ◽  
Southern Portugal ◽  
Bolinus Brandaris

The present study reports morphometric relationships and discusses the relative growth in the banded murex (Hexaplex trunculus) and the purple dye murex (Bolinus brandaris) from the Ria Formosa lagoon (southern Portugal). A total of 11 morphometric parameters (eight linear variables: shell length, shell width, total aperture length, aperture length, aperture width, spire length, spire width and siphonal canal length; three ponderal variables: total weight, soft parts weight and shell weight) were analysed in both species. The analyses comprised numerous individuals of both sexes and with broad size ranges (H. trunculus: 10.7–82.8 mm shell length; B. brandaris: 14.6–107.7 mm shell length), fairly representative of the populations from the Ria Formosa lagoon. In general, B. brandaris exhibited greater morphological plasticity and higher variability in shell shape compared with H. trunculus. In both species, the vast majority of morphometric relationships displayed positive allometries, distantly followed by negative allometries and by isometries. Although H. trunculus and B. brandaris are known to lack external sexual dimorphism, several morphometric relationships revealed significant differences in the type of growth between sexes, which should be further confirmed using more powerful techniques, such as geometric morphometric analyses of shell shape.

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.

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 How the fluctuations of water levels affect populations of invasive bivalve Corbicula fluminea (Müller, 1774) in a Neotropical reservoir?

2015 ◽  
Vol 75 (1) ◽  
pp. 135-143 ◽  
Author(s):  
LRP. Paschoal ◽  
DP. Andrade ◽  
G. Darrigran
Keyword(s):  
Population Structure ◽  
Spatial Distribution ◽  
Water Column ◽  
Shell Length ◽  
Native Species ◽  
Corbicula Fluminea ◽  
Water Levels ◽  
Hydroelectric Power Station ◽  
Hydroelectric Power ◽  
Significant Difference

Corbicula fluminea is an invasive bivalve responsible for several environmental and financial problems around the globe. Despite the invasive potential of this species, it suffers certain restrictions in lentic environments due to natural phenomena that significantly affect its population structure (e.g. water column fluctuation and sunlight exposure). The present study addresses how temporal decline of the water level in a Neotropical reservoir and exposure to sunlight affect the population structure of C. fluminea. Samplings were carried out twice in the reservoir of Furnas Hydroelectric Power Station (HPS) (Minas Gerais, Brazil), in 2011 and 2012. Population density, spatial distribution and mean shell length of C. fluminea were estimated for each year after sampling in 51 quadrats (0.0625m2) placed on three transects at different distances along the reservoir margins (0, 10 and 20 m from a fixed-point). We observed a predominance of C. fluminea in both years, with a simultaneous gradual decrease in density and richness of native species in the sampling area. Significant differences in density of C. fluminea were registered at different distances from the margin, and are related to the temporal variability of physical conditions of the sediment and water in these environments. We also registered a trend toward an increase in the density and aggregation of C. fluminea as we moved away from the margin, due to the greater stability of these areas (>10 m). The mean shell length of C. fluminea showed significant difference between the distinct distances from the margin and during the years, as well as the interaction of these factors (Distances vs.Years). These results were associated with the reproductive and invasive capacity of this species. This study reveals that these temporal events (especially water column fluctuation) may cause alterations in density, spatial distribution and mean shell length of C. fluminea and the composition of the native malacofauna in Neotropical lentic environments.

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.

Tracking parallel adaptation of shell morphology through geological times in the land snail genus Pupilla (Gastropoda: Stylommatophora: Pupillidae)

2020 ◽  
Author(s):  
Martin Haase ◽  
Stefan Meng ◽  
Michal Horsák
Keyword(s):  
Morphological Changes ◽  
Land Snail ◽  
Land Snails ◽  
Shell Morphology ◽  
Shell Shape ◽  
Ecological Niches ◽  
Habitat Requirements ◽  
Stochastic Nature ◽  
Niche Shifts ◽  
Molecular Phylogenetic

Abstract Changing environmental conditions force species either to disperse or to adapt locally either genetically or via phenotypic plasticity. Although limits of plasticity can be experimentally tested, the predictability of genetic adaptation is restricted due to its stochastic nature. Nevertheless, our understanding of evolutionary adaptation has been improving in particular through studies of parallel adaptation. Based on molecular phylogenetic inferences and morphological investigations of both recent and fossil shells we tracked the morphological changes in three land snails, Pupilla alpicola, Pupilla loessica and Pupilla muscorum. These species differ in habitat requirements as well as historical and extant distributions with P. alpicola and P. loessica being more similar to each other than to P. muscorum. Therefore, we hypothesized, that the three species reacted independently and individually to the conditions changing throughout the Pleistocene, but expected that changes within P. alpicola and P. loessica would be more similar compared to P. muscorum. Indeed, intraspecific shell shape differences across time were similar in P. alpicola and P. loessica, suggesting that similar niche shifts have led to similar transformations in parallel. In contrast, extant P. muscorum populations were practically identical in shape to their ancestors. They have probably tracked their ecological niches through time.

scholarly journals Prediction Accuracies of Genomic Selection for Nine Commercially Important Traits in the Portuguese Oyster (Crassostrea angulata) Using DArT-Seq Technology

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 210
Author(s):  
Sang V. Vu ◽  
Cedric Gondro ◽  
Ngoc T. H. Nguyen ◽  
Arthur R. Gilmour ◽  
Rick Tearle ◽  
...  
Keyword(s):  
Moisture Content ◽  
Genomic Selection ◽  
Shell Length ◽  
Prediction Accuracy ◽  
Genomic Information ◽  
Morphometric Traits ◽  
Shell Weight ◽  
Shell Width ◽  
Crassostrea Angulata ◽  
Selection For

Genomic selection has been widely used in terrestrial animals but has had limited application in aquaculture due to relatively high genotyping costs. Genomic information has an important role in improving the prediction accuracy of breeding values, especially for traits that are difficult or expensive to measure. The purposes of this study were to (i) further evaluate the use of genomic information to improve prediction accuracies of breeding values from, (ii) compare different prediction methods (BayesA, BayesCπ and GBLUP) on prediction accuracies in our field data, and (iii) investigate the effects of different SNP marker densities on prediction accuracies of traits in the Portuguese oyster (Crassostrea angulata). The traits studied are all of economic importance and included morphometric traits (shell length, shell width, shell depth, shell weight), edibility traits (tenderness, taste, moisture content), and disease traits (Polydora sp. and Marteilioides chungmuensis). A total of 18,849 single nucleotide polymorphisms were obtained from genotyping by sequencing and used to estimate genetic parameters (heritability and genetic correlation) and the prediction accuracy of genomic selection for these traits. Multi-locus mixed model analysis indicated high estimates of heritability for edibility traits; 0.44 for moisture content, 0.59 for taste, and 0.72 for tenderness. The morphometric traits, shell length, shell width, shell depth and shell weight had estimated genomic heritabilities ranging from 0.28 to 0.55. The genomic heritabilities were relatively low for the disease related traits: Polydora sp. prevalence (0.11) and M. chungmuensis (0.10). Genomic correlations between whole weight and other morphometric traits were from moderate to high and positive (0.58–0.90). However, unfavourably positive genomic correlations were observed between whole weight and the disease traits (0.35–0.37). The genomic best linear unbiased prediction method (GBLUP) showed slightly higher accuracy for the traits studied (0.240–0.794) compared with both BayesA and BayesCπ methods but these differences were not significant. In addition, there is a large potential for using low-density SNP markers for genomic selection in this population at a number of 3000 SNPs. Therefore, there is the prospect to improve morphometric, edibility and disease related traits using genomic information in this species.

Spatial Simulation of Precipitation Resources in Chongqing

2012 ◽  
Vol 518-523 ◽  
pp. 4261-4265
Author(s):  
Xiao Song Lin ◽  
Sha Sha Yu ◽  
Hai Yan Wang
Keyword(s):  
Spatial Distribution ◽  
Spatial Interpolation ◽  
Regional Difference ◽  
Interpolation Method ◽  
Annual Precipitation ◽  
Regression Equations ◽  
Spatial Simulation ◽  
Simulation Data ◽  
Spatial Interpolation Method ◽  
Precise Simulation

Years’ precipitation data of Chongqing from 101 metrological stations has been adopted in the paper and the regression equations between annual precipitation and altitude, longitude, and height have been obtained by the use of SPSS, then elaborate simulation of Chongqing’s precipitation resources based on regression analysis was completed through the 1km×1km grid system and fitted equation. Elaborated simulation of precipitation resources was realized by best spatial interpolation method with the support of GIS; then the results of two different simulation methods were coupled in the form of linear combination to obtain the coupling simulation of spatial distribution of Chongqing’s precipitation resources, finally the precipitation resources were summed up and distributed according to different administration areas at county level and thus obtain precise simulation data of precipitation resources in each county of Chongqing. The results showed that there is a remarkable regional difference in the spatial distribution of precipitation resources of Chongqing, and it decreases from the southeast to the northwest in general, with the annual precipitation higher than 1270mm in southeast and lower than 1080mm in northwest.

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