Terrestrial Snail Research Articles

Biocontrol potential of some bacterial and fungal isolates against the terrestrial snail, Monacha obstructa, evaluating their laboratory and field efficiency

BackgroundThe land snail Monacha obstructa, commonly known as the glassy clover snail, poses a significant threat to crops, causing substantial damage in agriculture and horticulture. It particularly thrives in regions of Egypt, where it can reproduce rapidly, leading to substantial population increases and consequent damage. This study aimed to perform laboratory experiments and field trials to assess the effectiveness of bacterial (Bacillus thuringiensis) and fungal (Metarhizium anisopliae and Trichoderma harzianum) isolates, as well as methomyl, a carbamate compound approved by the Ministry of Agriculture in Egypt against the terrestrial snails. Various methods including contact and leaf dipping as well as baiting techniques were applied under both laboratory and field conditions, using spray and baiting techniques.ResultsBacillus thuringiensis (Bt) and M. anisopliae isolates showed the most effective results outcomes in comparison with methomyl against M. obstructa. Out of all the application approaches tested, the residual film (contact) technique of these microorganisms proved to be the most potent, with LC50 values of 6.49 × 106 cells/ml Bt (after 14 days), 1.24 × 108 and 1.49 × 108 spores/ml (M. anisopliae, T. harzianum, respectively), after 21 days and 620 ppm, for methomyl after 7 days of treatments. Besides, the findings demonstrated that Bt exhibited the highest success rate in decreasing the number of snails in the field. It was also observed that pathological symptoms increased as the duration of exposure increased, and the snails ceased to feed and showed a noticeable decline in their activity. A slimy, almost tan-like substance coated the exterior of their shells for Bt, and part of the soft body came out of the shell for M. anisopliae. In the case of T. harzianum, fungus hypha growth took on a white color formed inside the shell, and in addition, a black substance formed on the mouth of the shell.ConclusionsThe gathered data revealed that Bt and M. anisopliae effectively combatted the terrestrial snail, making them viable options in integrated pest control as substitutes for pesticides.

Local terrestrial snails as natural intermediate hosts of the zoonotic parasite Angiostrongylus cantonensis in the new European endemic area of Valencia, Spain.

The rat lungworm, Angiostrongylus cantonensis, has recently been found in the city of Valencia, parasitizing rats, Rattus norvegicus and Rattus rattus, its natural definitive hosts. This is the first finding of this zoonotic nematode in continental Europe. After informing local and national health authorities, the collection of local terrestrial snails took place with the aim of elucidating their potential role as intermediate hosts of A. cantonensis. A total of 145 terrestrial snails, belonging to the species Cernuella virgata, Cornu aspersum, Eobania vermiculata, Otala punctata, Pseudotachea splendida, Rumina decollata and Theba pisana, were randomly collected between May and December 2022 in public gardens, parks and orchards in six districts of Valencia, in five of which A. cantonensis had been reported previously in rats. Once collected and identified, the snails were frozen at -20°C. Subsequently, the DNA was isolated and screened by PCR using specific primers targeting the A. cantonensis COI gene. Seven individual snails, belonging to the species C. virgata, C. aspersum and T. pisana, were positive, for an overall prevalence of 4.8%. The PCR product from one of them was sequenced by Sanger sequencing. The three positive terrestrial snail species are among the edible species that are frequently included in various dishes in Spain. C. virgata is reported as a previously unrecorded intermediate host and should be added to the list of more than 200 species of terrestrial snails that have been reported worldwide as intermediate hosts of the rat lungworm. Considering that these terrestrial snails may release infective larvae of A. cantonensis on leafy green vegetables on which they feed and during their handling and preparation for consumption, prophylactic measures to prevent human neuroangiostrongyliasis in Valencia and other regions to which this zoonotic parasite may spread are recommended.

High‐Resolution Intrashell Oxygen Isotope Studies of Cathaica fasciola and Bradybaena ravida Land Snails and Their Environmental Implications

AbstractIntrashell oxygen isotope (δ18Os) analyses of terrestrial snails have been carried out over two decades. However, the intraspecies/interspecies differences are not yet well understood. Here, we conducted a high‐resolution intrashell δ18Os study on 43 shells from Cathaica fasciola and Bradybaena ravida, and 1449 δ18Os data were obtained. These large amounts of data demonstrate the reproducibility of intrashell δ18Os. Our results suggest that C. fasciola and B. ravida have similar growing seasons mainly from March to October in the studied region. The ecological habits of the two species could explain the distinctive variations in their δ18Os sequences. Therefore, our study may interpret the discrepancy between the studies of land snail species and the stable/clumped isotopes of their shells. Moreover, the calculated average growth rate is ∼290 μm/day (from 250 to 330 μm/day) for nonadult C. fasciola. Thus, the use of snail shells for reconstructing high‐resolution terrestrial climate changes is promising.

Intercontinental dispersal and niche fidelity drive 50 million years of global diversification in Vertigo land snails

AbstractAimWe aimed to understand how biogeographical processes and moisture niche ecology contributed to the spatio‐temporal diversification dynamics in the land snail genus Vertigo.LocationGlobal (North America, Europe, Asia, Africa).Time PeriodCenozoic era.Major Taxa StudiedMinute terrestrial snails of the genus Vertigo.MethodsWe reconstructed a time‐calibrated phylogeny of 94 Vertigo taxa (~85% of all known extant species) based on mitochondrial and nuclear DNA data. Leveraging this phylogeny with distributional and ecological data from >7000 populations, we performed biogeographic and ecological modelling to investigate evolutionary mechanisms of global Vertigo diversification.ResultsVertigo has diversified since the Early Eocene, ca. 47.6 Ma (95% HPD = 46.0–52.7), with its six subgenera originating from the Late Eocene (30.2–48.7 Ma) to the Early Miocene (13.3–23.0 Ma). Species diversity accumulated linearly, with a slight increase 35–30 and 25–20 Ma, coinciding with the emergence of most subgenera and northern hemisphere cooling, respectively. Biogeographic modelling indicated that most diversification events occurred in sympatry (no range modification), but that rare founder events drove global diversification. Soil moisture conditions, a major variable defining Vertigo niches, displayed significant phylogenetic signal, but varied less among subgenera relative to within. Shifts in biogeographical ranges and moisture niches (or the absence thereof) were significantly associated at macroevolutionary scales, with most niche shifts upon sympatric cladogenesis and hardly any upon founder‐event speciation.Main ConclusionsOur results indicate that ecological shifts in soil moisture niches occasionally drove cladogenesis in sympatry and anagenetic range extensions, but that long‐distance dispersal was mainly successful in the absence of such shifts. A combination of neutral (founder events and drift) and selective mechanisms (adaptive habitat shifts) has determined the macroevolutionary success of Vertigo. Our results imply that species with high niche fidelity or fewer opportunities for long‐distance dispersal will be more vulnerable to future anthropogenic stressors.

Morphological and Molecular Identification of Some Terrestrial Snails: First Report

Morphological and Molecular Identification of Some Terrestrial Snails: First Report

Assessment of terrestrial snails’ diversity and composition in six forests of west central - Morocco along an altitudinal gradient

This study aims to investigate the diversity of terrestrial gastropods in west-central Morocco. It also examines how elevation and other abiotic factors affect the distribution and composition patterns of said malacofauna. The sampling covered six different forest sites with thirty stations spanning on an altitudinal gradient that ranges from 24 to 2434m. The influence of abiotic factors on species richness and abundance was evaluated via the Pearson correlation. The Shannon index evaluated the malacofaunal diversity within each station. Whittaker’s index assessed heterogeneity of each forest site. The similarity between the forest sites was determined by multivariate analyses; namely the Jaccard index and the Nonmetric Multi-Dimentional Scaling analysis (NMDS). A total of 31312 specimens representing 30 species were recorded. Low altitude stations display the highest values of diversity and uniformity, while the highest altitude stations present the opposite trend. The NMDS analysis revealed that the elevation and vegetation type represent the principal factors affecting the distribution of land snails in the six forest sites.

Thermal Impact and the Relevance of Body Size and Activity on the Oxygen Consumption of a Terrestrial Snail, Theba pisana (Helicidae) at High Ambient Temperatures.

Metabolism, mainly driven by oxygen consumption, plays a key role in life, as it is one of the main ways to respond to extreme temperatures through internal processes. Theba pisana, a widespread Mediterranean land snail, is exposed to a wide range of ambient temperature. In this species the oxygen consumption was tested as a response variable by multiple regression modelling on the "explanatory" variables shell-free mass, temperature, and relative humidity. Our results show that the oxygen consumption of T. pisana can be well described (73.1%) by these three parameters. In the temperature range from 23 °C to 35 °C the oxygen consumption decreased with increasing temperature. Relative humidity, in the range of 67% to 100%, had the opposite effect: if it increases, oxygen consumption will increase as well. Metabolism is proportional to an individual's mass to the power of the allometric scaling exponent α, which is between 0.62 and 0.77 in the mentioned temperature range. CT scans of shells and gravimetry revealed the shell-free mass to be calculated by multiplying the shell diameter to the third power by 0.2105. Data were compared to metabolic scaling exponents for other snails reported in the literature.

Contribution of Epigenetic Mechanisms to the Formation, Maintenance, and Reconsolidation of a Long-Term Food-Related Aversive Memory in Terrestrial Snails

Contribution of Epigenetic Mechanisms to the Formation, Maintenance, and Reconsolidation of a Long-Term Food-Related Aversive Memory in Terrestrial Snails

Effect of Boiling on Chemical Composition of Small Brown Snail (Cornu aspersum aspersum) Meat

Abstract The aim of this study was to assess the changes occurring as a result of boiling (100°C, 1 h) small brown snail (Cornu aspersum aspersum) meat in relation to its proximate composition, calcium, phosphorus and cholesterol content, as well as the profile of fatty acids and nutritional quality indices of the lipids. This species of snail was selected for research because it is currently of the greatest economic importance among edible terrestrial snails. It was hypothesized that the cooking effect may be different for foot and visceral sac. Samples for the research were collected from 6 populations bred on experimental fields of the National Research Institute of Animal Production in balice (Poland). The foot and the visceral sac, the edible parts of the snail species under investigation, were analysed separately, raw and boiled in water. The results were then compared to analogous studies carried out by other authors on beef, pork and poultry. It was found that in the visceral sac of Cornu aspersum aspersum the shares of dry matter, crude protein, fat, ash, calcium and phosphorus were greater than those in the foot (P<0.05), both in the raw and boiled material, whereas the cholesterol content was higher in the foot (P<0.05). Generally, especially in the foot, the heat treatment elevated the levels of the afore-mentioned quantities, yet the increases were not always statistically significant. Boiling the snail meat caused moderate changes in the fatty acid composition. The profile of the fatty acids and the nutritional quality indices of the foot fat were more advantageous than those in the visceral sac. In both parts of the snail carcass, the polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) ratio substantially exceeded the minimum value of 0.45 recommended by the British Department of Health. However, the n-6/n-3 ratio was too high, exceeding the maximum recommended level of 4.0 twofold and as much as threefold in the case of the foot and the visceral sac, respectively. In the foot, due to boiling, an increase of the share of sfa and monounsaturated fatty acids (MUFA) was observed, while PUFA, n-6 and n-3 decreased. In the visceral sac, the changes were less pronounced with a slight decrease of the share of sfa and PUFA, and an increase of MUFA. Therefore, in the foot, boiling worsened the PUFA/SFA ratio, the nutritive value index (NVI = (C18:0 + C18:1) / C16:0) and dietary fatty acids having a desirable neutral and hypocholesterolemic effect in humans (DFA = Σ MUFA + Σ PUFA + C18:0), but in the visceral sac these indices practically did not change. On the whole, the trends of the changes in terms of chemical composition due to boiling found in the small brown snail meat are similar to those after heat treatment of meat from popular farm animals, but the ranges of the changes differ.

Species identification method by a new non-invasive technique in Korean endangered terrestrial snail, Koreanohadra Koreana (Gastropoda: Mollusca)

Koreanohadra koreana (K. koreana) is an endemic species in South Korea that is listed as endangered. While the ecology and phylogenetics of K. koreana have been studied, its morphological similarity to the related species Koreanohadra kurodana (K. kurodana), can make species identification difficult. Furthermore, this has led to confusion when determining essential habitat information for the conservation of K. koreana. To bypass this issue, we have developed a non-invasive species identification method that can genetically differentiate between them. While there are already various non-invasive genomic DNA (gDNA) extraction methods that utilize the mucus from mollusks, they are limited as they require the target species to be physically located. To address this, in this investigation a method of extracting gDNA from the feces of snails was developed. The method utilized a primer set to amplify a cytochrome b fragment from K. koreana but not K. kurodana or other terrestrial snails. The feces of terrestrial snails could thus be used to obtain gDNA to a genetically usable level if collected within 5 days of excretion. This non-invasive species identification method using feces will help to facilitate genetic research without harming the endangered species and if the target species is not physically in the habitat. Moreover, K. koreana and K. kurodana could perhaps be further distinguished, using their habitat information to help facilitate essential conservation measures.

Genetic diversity of a short-ranged endemic terrestrial snail.

The factors that influence population structure and connectivity are unknown for most terrestrial invertebrates but are of particular interest both for understanding the impacts of disturbance and for determining accurate levels of biodiversity and local endemism. The main objective of this study was to determine the historical patterns of genetic differentiation and contemporary gene flow in the terrestrial snail, Austrochloritis kosciuszkoensis (Shea & O. L. Griffiths, 2010). Snails were collected in the Mt Buffalo and Alpine National Parks in Victoria, in a bid to understand how populations of this species are connected both within continuous habitat and between adjacent, yet separate environments. Utilising both mitochondrial DNA (mtDNA) and single nucleotide polymorphism (SNP) data, the degree of population structure was determined within and between sites. Very high levels of genetic divergence were found between the Mt Buffalo and Alpine snails, with no evidence for genetic exchange detected between the two regions, indicating speciation has possibly occurred between the two regions. Our analyses of the combined mtDNA and nDNA (generated from SNPs) data have revealed patterns of genetic diversity that are consistent with a history of long-term isolation and limited connectivity. This history may be related to past cycles of changes to the climate over hundreds of thousands of years, which have, in part, caused the fragmentation of Australian forests. Within both regions, extremely limited gene flow between separate populations suggests that these land snails have very limited dispersal capabilities across existing landscape barriers, especially at Mt Buffalo: here, populations only 5 km apart from each other are genetically differentiated. The distinct genetic divergences and clearly reduced dispersal ability detected in this data explain the likely existence of at least two previously unnamed cryptic Austrochloritis species within a 30-50 km radius, and highlight the need for more concentrated efforts to understand population structure and gene flow in terrestrial invertebrates.

Phylogeography of two codistributed terrestrial snails in the Maputaland–Pondoland–Albany biodiversity hotspot, South Africa

Abstract We investigated the evolutionary patterns of two forest-dwelling endemic terrestrial snails (Gittenedouardia spadicea and Maizania wahlbergi) in the Maputaland–Pondoland–Albany biodiversity hotspot in South Africa to examine the degree of phylogeographical congruence between the two species. Phylogenetic relationships and divergence time estimations within each species were inferred using the combined mitochondrial DNA (mtDNA) sequence dataset for the cytochrome c oxidase subunit I (COI) and large subunit ribosomal RNA (16S rRNA). In addition, the rapidly evolving COI datasets were used to infer intraspecific genetic structure and population differentiation within both species. Phylogeographical concordance factor (PCF) analysis was used to statistically estimate the degree of congruence between the two species at localities where both species were sampled. Phylogenetically, G. spadicea exhibited two clades that diverged during the Plio/Pleistocene, while M. wahlbergi formed a single shallow clade that showed Pleistocene divergence. The haplotype networks for the COI locus demonstrated evidence of geographical and genetic isolation within both species. PCF analysis demonstrated partial phylogeographical concordance, suggesting that the two species may have been affected by similar ancient climatic events. Traits other than poor dispersal capabilities and limited gene flow may also influence how a species responds to fluctuating climate change.

Seven new narrowly endemic species of Gulella Pfeiffer, 1856 from eastern South Africa (Gastropoda, Streptaxidae) and status revision for another

Seven new species of very small Gulella Pfeiffer, 1856 are described from two regions in the interior of south-eastern South Africa within the Maputaland-Pondoland-Albany biodiversity hotspot. In addition, the status of Gulella darglensis benthodon van Bruggen, 1980 is revised and raised to species level. All species are very small-shelled and are narrow-range endemics. Six species, G. judithmastersae sp. nov., G. kevincolei sp. nov., G. hlathikhulu sp. nov., G. nkandla sp. nov., G. mystica sp. nov. and G. libertas sp. nov. are each known from only one locality. The first two as well as G. benthodon and G. mcmasteri sp. nov. are found only in the Amathole Mountains, where poaching, illegal harvesting of plant products and uncontrolled access of cattle take place, including in protected areas. The other four species each occur at one locality in north-central KwaZulu-Natal. The localities of three of the last-mentioned species are in protected areas although they are isolated and surrounded by a heavily transformed cultural landscape rendering enforcement of conservation legislation a challenge. Six species occur in nature reserves, highlighting the importance of small pockets of protected habitat for the conservation of terrestrial snails.

Primacy and recency in snails (Cornu aspersum).

Pavlovian conditioning has been proven to be useful for the study of associative learning and animal cognition. This procedure can be used to observe certain memory phenomena. The appetitive conditioning of several neutral stimuli can result in higher response rates, and therefore a better memory, for the first and last stimuli of the series. This is equivalent to primacy and recency effects. In this work, the tentacle lowering procedure was employed to study these phenomena in the snail (Cornu aspersum). Subjects experienced five odorous conditioned stimuli (CS) paired with food (conditioning) in a specific order followed by the exposure to the CSs alone to measure the conditioned response (CR, conditioning test). For Experiment 1, the serial presentation of the five reinforced odors resulted in a higher CR for the initial and final odors in comparison with the middle ones. In Experiment 2, it was established that a 20-min trial is enough to produce appetitive conditioning in snail. For Experiment 3, the results of Experiment 1 were replicated while controlling for odor presentation order. Finally, in Experiment 4, the serial position effect was obtained when the interval between conditioning and test phases were minimized. The results observed in the present study provided evidence of the serial position effect in terrestrial snails. The theoretical implications of these are debated. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Fungi as Control Bioagents Against the Terrestrial Snail, Eobania vermiculata

Fungi as Control Bioagents Against the Terrestrial Snail, Eobania vermiculata

Precipitation δ18O paced the seasonal δ18O variations of terrestrial snail body water and shells in the East Asian monsoon region

Terrestrial snails are sensitive to climate changes and their shell's oxygen isotope composition (δ18Oshell) is widely used in studies of paleoclimate reconstructions. However, the interpretation of δ18Oshell remains complex due to the combined effects from different factors such as precipitation δ18O (δ18Op), relative humidity (RH), and temperature. Furthermore, no systematic studies have addressed the transformation of oxygen isotope signals from rainfall to the aragonite shell via snail body water. Here we present the results of Cathaica fasciola body water δ18O (δ18OBW) and its content, which were sampled every two days throughout the growing season in 2021 in Xi'an. Meanwhile, the soil water δ18O (δ18OSW), δ18Op, rainfall amount, RH and temperature were also simultaneously monitored, and two high-resolution (at ∼0.3 mm interval) δ18Oshell series were obtained from two live snails collected in September and October 2021, respectively. These data reveal that the δ18OBW mimic the variations of δ18Op, and they are positively correlated (r2 = 0.84) for precipitation events and the correlation coefficient only increases slightly (r2 = 0.88) when RH is included in the multivariate analysis. During non-precipitation intervals, there is an obvious negative correlation between δ18OBW and RH. Moreover, the variations of two δ18Oshell series are broadly consistent with the theoretically calculated δ18Oshell from δ18OBW/δ18Op at seasonal scale. Collectively, this study demonstrates that δ18Op is the first-order control on the seasonal variations of δ18OBW and δ18Oshell, while RH play its role during non-precipitation periods. Importantly, this study lays good foundation for reconstructing terrestrial seasonal distribution of precipitation and extreme rainfall events using fossil shells in the geological past.

The diversity and abundance of terrestrial snails in yankari game reserve, bauchi state, Nigeria

Land snails represent one of the most important groups of invertebrates in terrestrial ecosystems; this study was aimed at determining the distribution and abundance of land snails in Yankari Game Reserve Bauchi State, Nigeria. Land snails were investigated in Yankari using a combination of direct search and litter sieving techniques. 10 plots were sampled randomly within an area of 100m × 100m so as to have a good spread of each site. Soil sample were collected within each of the plots and analyzed for soil pH, total nitrogen, organic carbon, calcium and moisture content. A total of 103 specimens comprising of six species belonging to four molluscan families were collected from ten plots in Yankari Game Reserve. This showed that the molluscs were moderately diverse. The family, Achatinidae dominated the fauna in Yankari Game Reserve. This study has revealed that the land fauna in Yankari are moderately diverse with low densities. The result indicates that not all the sampling areas of the reserves had much species; it is therefore presumed that there may be richer areas of land snails which were not sampled in both sites.

Assessing the molluscicidal and biochemical activities of New-Fort®, an inorganic fertilizer against Theba pisana snails

Terrestrial snails are a significant issue in agricultural production worldwide. The use of nitrogen - phosphorus - potassium (NPK) based fertilizers played an important role in meeting the food demand throughout the world, so its effectiveness against land snails needs to be investigated. This study was conducted to evaluate toxic lethal effect of New-Fort®, an inorganic NPK based fertilizer, in the field for 3, 7 and 10 days and in the laboratory for 24, 48 and 72 h against Theba pisana snails. Also, the impact of its sub-lethal doses (1/10, 1/5, 1/4 and 1/2 of 48 h-LD50) on biochemical parameters were determined under laboratory conditions. The results showed that the snails percent reduction in the field were 21.4, 61.0 and 80.0 % after 10 days' application of quarter, half and one field rate and the values of LD50 in the laboratory were 4.94, 4.56 and 4.24 mg/g b.w at 24, 48 and 72 h, respectively. New-Fort® sub-lethal doses caused a significant inhibition in catalase, γ-glutamyl transferase and acetylcholinesterase activities. It also elicited a significant elevation in glutathione S-transferase activity post exposure to 1/10 and 1/5 of LD50, whereas an opposite effect was occurred after exposure to 1/4 and 1/2 of LD50. Lipid peroxidation level was reduced in snails treated with 1/10 and 1/5 of LD50, whereas it increased in 1/4 and 1/2 of LD50- treated snails. Moreover, a significant inhibition in alkaline phosphatase activity at all tested doses, with the exception of 1/2 of LD50 was observed. An increase in alanine aminotransferase and aspartate aminotransferase activities were occurred after all tested doses exposure. Our findings highlighted on how biochemical changes can be exploited to better understand the mechanisms underlying New-Fort® fertilizer toxicity against the land snail, T. pisana, as well as how to benefit from NPK fertilizers application in snail control.

A multi-region study of carbonate clumped isotope data from terrestrial snails

The stable oxygen isotope composition (δ18O) of land snail shells has been used for decades to provide insight into past changes in δ18Oprecipitation, relative humidity, moisture source and several other paleoenvironmental parameters across diverse environments and ecosystems. Recently, carbonate clumped isotope values (Δ47) recorded from land snail shells have also been applied as a geothermometer. However, there is limited information available regarding the relationship between modern shell geochemistry and paleoenvironmental conditions for regions with contrasting climates, which is needed for further contextualization and validation of snail shell temperature proxies. Our study utilizes paired Δ47 and δ18Oshell measurements in terrestrial snail shells to reconstruct temperature (T47) and δ18Obody water composition, which are two key variables used for the study of regional and sub-regional paleoclimates and paleoecosystems. We examine shells from three geographical regions with distinct hydroclimates: Central Europe, the Canary Islands, and the Chinese Loess Plateau. To constrain the timing of shell growth, we compare snail shell isotope-derived climate parameters to independent environmental data, including mean annual, warm season, and rainy season temperatures, assuming snail shells mineralize during the optimal activity range of 15–25 °C. Our results indicate that values for samples from the Canary Islands are most consistent with year-round growth; Chinese Loess Plateau samples are most consistent with summer growth; and samples from Central Europe are most consistent with growth between spring and autumn. Calculated values of δ18O body water in snail shells were found to be enriched relative to the value of δ18Oprecipitation for the season of growth, with values ranging from ∼1–5‰. Altogether, our data suggest that Δ47 and δ18O measurements from terrestrial snail shells represent a useful archive of environmental temperature and humidity. However, their application in the paleo-record requires careful consideration of the ecophysiology of the taxa, and the climate of the region.

Phasmarhabditis eagyptiaca n. sp. (Nematoda: Rhabditidae) Isolated from Egyptian Terrestrial Snails and Its Role as Control Bio-agentto Gastropods.

To date nineteen nematode species in the genus Phasmarhabditis Andrássy, 1976 recorded and described. This paper describes Phasmarhabditis eagyptiaca n. sp. (Nematoda: Rhabditidae), morphologically and phylogenatically and investigate its role as bio control agent for gastropods. Snails infected with nematode collected from Great Cairo Egypt. Sequences of the 18S ribosomal (18S rRNA) gene performed and used for phylogenetic studies. Morphological parameter measured and the nematode photographed and illustrated. Bioassay conducted on some snails and slugs species. Phasmarhabditis eagyptiaca n. sp. is the second new species of the genus Phasmarhabditis recorded and described in Egypt after Phasmarhabditis tawfiki Azzam2003, the fourth species from Africa and the 20th from the world. Morphological and molecular parameter showed that the new isolate is close to other species of Phasmarhabditis, especially Phasmarhabditis neopapillosa Andrássy, 1983, Phasmarhabditis hermaphrodita (Schneider, 1859) and P. tawfiki Azzam with high bootstrap supported values (99.25%, 98.85%, and 98.64%, respectively). This nematode could infect and killed all snails and slugs exposed to infection in laboratory. Phasmarhabditis eagyptiaca n. sp. differs from all previously recorded species by shorter tail of female spikey tail of male and the arrangement of genital papillae formula which different from all previous species. It could be confirmed that this nematode is a new species of Phasmarhabditis. This nematode could be considering a biological control agent for snails and slugs.