Tag Archives: achatinidae

Venezuelan land snails

The following report was found on Facebook, with land snails data from NE Venezuela, a region for which hardly reliable data exist in literature.


foto van Ignacio Agudo.
foto van Ignacio Agudo.
foto van Ignacio Agudo.

Ignacio Agudo aan Moluscos del Caribe/ Moluscos do Caribe/ Caribbean Mollusks


Total of seventeen (17) verified species (thirteen (13) terrestrial — two (2) non-native/ exotic — and four (4) freshwater forms — one non-native/ exotic), found in “xerophytic environments” of the parish until “December 2016”, distributed in fourteen (14) genus and nine (9) families.

Important to highlight that, in addition to the three (3) other specifically native aquatic/ limnic forms, all the thirteen (13) native terrestrial species so far detected in the region “contradictorily” correspond to own forms of environments/ humid forest ecosystems ……….


– Family HELICINIDAE Férussac, 1822
Helicina tamsiana (Pfeiffer, 1850)

– Family NEOCYCLOTIDAE Kobelt & Möllendorff, 1897
Poteria fasciatum (Kobelt & Schwanheim, 1912)

– Family AMPULLARIIDAE Gray, 1824
Pomacea glauca (Linnaeus, 1758)
Marisa cornuarietis (Linnaeus, 1758)

– Family LYMNAEIDAE Rafinesque, 1815
Pseudosuccinea columella (Say, 1817)

– Family PLANORBIDAE Rafinesque, 1815
Drepanotrema lucidum (Pfeiffer, 1839)

– Family ORTHALICIDAE Albers, 1860
Bulimulus cacticolus (Reeve, 1849)
Bulimulus constrictus Pfeiffer, 1841)
Bulimulus krebsianus Pilsbry, 1897
Drymaeus multilineatus (Say, 1825)
Oxystyla abducta (Shuttleworth, 1856)
Oxystyla maracaibensis (Pfeiffer, 1899)
Plekocheilus (Eudolichotis) distortus (Bruguière, 1789)

– Family ODONTOSTOMIDAE Pilsbry & Vanatta, 1898
Biotocus (- Tomigerus) cumingi (Pfeiffer, 1849) [according to Simone, 2006: Biotocus cumingi]

– Family SUBULINIDAE Fischer & Crosse, 1877
Beckianum beckianum (Pfeiffer, 1846)
Subulina octona (Bruguière, 1798)

– Family ACHATINIDAE Swainson, 1840
Achatina (Lissachatina) fulica (Bowdich, 1822)

The adjective ‘native’ which is used here, should be considered with care. E.g., the Subulinid and Achatinid species have been introduced, and also Drymaeus multilineatus has probably been introduced in the past. The list contains thus several species which originate from elsewhere, which is no big surprise as the locality is at the coast.

Apart from some minor errors (Bulimulus and Drymaeus belong to the family Bulimulidae; Oxystyla should be Orthalicus, abducta = obductus), this is information from a country with comparably hardly good information in the malacological literature.

Population structure Megalobulimus

Miranda et al. (2015) published (advanced online) a paper dealing with two Megalobulimus species. Their abstract reads as follows: “Native Megalobulimus paranaguensis was identified on Brazil’s Ilha Porchat promontory, an area that Achatina fulica commonly populates. The population structures of these species were investigated for interactions. Spatial distribution, niche overlap and mark–recapture analysis were conducted. The outer lip of M. paranaguensis and environmental variables were measured.

Miranda f3

Miranda f2

One and two abundance peaks were observed for A. fulica and M. paranaguensis, respectively. Survivorship was higher in A. fulica. Distribution was aggregate for M. paranaguensis, whereas for A. fulica it varied from random to aggregate. Both species aggregate as abundance increases. The lifespan of M. paranaguensis in this location is shorter than its lifespan in a nearby location. Achatina fulica was affected by soil temperature and humidity; M. paranaguensis was influenced by humidity. Niche overlap was random. The results show that M. paranaguensis can keep its
natural activity and abundance in the presence of A. fulica, but environmental degradation impacts M. paranaguensis and should be evaluated.”

As can be seen from the above figures, the observations were made during one year resp. 7 months. The conclusions thus have to be viewed within the context of this limited evidence.

Miranda, M.S., Fontenelle, J.H. & Pecora, I.L. (2014 [2015]). Population structure of a native and an alien species of snail in an urban area of the Atlantic Rainforest. – Journal of Natural History, 49: 19-35.

GAS in Brazil (MSc. thesis)

The Giant African Snail (Lissachatina fulica) is around in Brazil for more than 30 years. Aquino (2013) has made his Master thesis on this subject within the framework of biology and health policy. Since this kind of theses is often difficult to grasp (no formal publication, unless the author takes the effort to write also a paper summarising the data), it is mentioned here. As an exception, the full text (in Portuguese) is added after the reference.


The abstract reads: “Since it had been introduced in Brazil dating back to the 80s, the Great African Snail Achatina fulica has spread all over the country. Some researchers associate its incredibly good adaptation success to the dermal mucous of this species. With the objective and the aim of better knowing and understanding the dermal mucous of the Great African Snail and also suggesting new forms of taking advantage of it with a view to controlling this invading and exotic snail, this study work carried out the chemical characterization of the shell, of the snail without the shell and of the dermal mucous of the Great African Snail in the State of Alagoas, Brazil, and also evaluated and assessed the scarring/healing action of a solution from the mucous, already confirmed for skin tissue, in corneal ulcers surgically produced in rabbits. The wild snails were kept in a laboratory utilizing a new methodology specially developed for keeping arboreal snails in laboratory, with sensibly improved hygienic conditions, reduction of the time spent for the daily treatment and reduction of animal stress. This methodology has been described in details at the XXII EBRAM in 2011, in Fortaleza, State of Ceará, Brazil, and published in the form of a scientific article under the name “new breeding management for snails (molusca: gastropoda: pulmonata) in plastic boxes (recipients/containers)”. The following analyses were carried out: the mineral composition of the snail without its shell, of the shell and of the mucous; the centesimal composition of the lyophilized mucous and the anti oxidizing capacity evaluated through the seizing activity of the free radical 2,2-diphenyl- 1-picryl-hydrazyl (DPPH). With regards to the results, the macro and micro minerals composition present in the snail without a shell, in the shell and in the dermal mucous of the A. fulica was determined for 23 nutrients, 5 macro-nutrients (Ca, P, Na, K and Mg) and 18 micro-nutrients (Al, As, Ba, Cd, Cr, Cu, Fe, Li, Mn, Mo, Ni, Si, Sr, V, Zn, Co, Sb and Se). With regards to the centesimal composition, the following data was obtained: dried matter (91.72 ± 1.85), humidity (8.28 ± 0.97), ashes (31.1 ± 0.35), crude protein (49.97 ± 3.21), carbohydrates (8.15 ± 1.43), total calories (242.48 ± 53.23), lipids in 100 g (2.5 ± 0.44), cholesterol (50.2 ± 0.3). The mucous did not show anti oxidizing capacity in any of the analysed samples. For the experiment in vivo, the evolution of the corneal lesions on the 18 rabbits, divided in three groups of 6 animals: the control group, the mucous group and the group treated with the ophthalmic solution Epitegel, was accompanied and monitored by the percentage measurement of scarring/healing of the 36 areas of scarring through 144 macro photographs taken along the experiment at 0, 24, 48 and 72 hours. To carry out the experiment, duly approved by the Ethical Committee of UFAL (The Federal University of Alagoas), process no. 010190/2011-85, a scalpel blade to remove the corneal epithelium previously circumscribed by a circular scalpel (punch no. 5) and the anaesthetic protocol utilized comprised 3 steps: tranquilizing with acepromazine (0,05 mg / kgPV/IM), anaesthetizing with cetamine chlorydrate (12mg/IM/kgPV) and local anesthetizing with proxymethacaine chlorydrate 0,5%. For the orientation regarding the ideal choice for mucous concentration for the treatment of the lesions on the experiment in vivo, solutions were tested in the following concentrations: 0.01 mg mL-1, 0.03 mg mL-1, 0.06 mg mL-1 and 0.125 mg mL-1. The cellular viability was verified through the MTT and Tripan Blue methods. No statistical differences were observed between the tested concentrations; therefore, the chosen concentration to be the base for the preparation of the ophthalmic solution was the one that gratifyingly better stimulated the cellular proliferation (0,125 mg mL-1). With regards to the results, there were no statistical differences between the mucous group and the Epitegel; the ophthalmic solution based on the mucous (0,125 mg 25 μL) had a similar performance to the ophthalmic solution Epitegel 10g (Ophthalmological Gel Dexpantenol 50 mg g-1, positive control), one of the best available medicines in the market for the treatment of corneal ulcers/lesions. Nevertheless, both presented some significance regarding the result of the control group, which presented a longer scarring/healing time. With 72 hours, of the 12 lesions of the control group, only 2 (16,66%) were scarred/healed; of the Epitegel group, only 8 (66,66%) were scarred/healed and of the mucous groups, all (100%) were scarred/healed. It has been thus demonstrated the scarring/healing capacity of the A. fulica’s mucous also for the treatment of corneal ulcers and its specific action, furthermore than merely accelerating the recovery of lesions in animals and it also did not produce, in any of them, a single visible scar. It is yet to be exactly known its action mechanism in conjunction with the set of steps of the corneal scarring/healing, especially if it detains a stimulating action over the reproduction of trunk cells, which are responsible for the regeneration of this epithelium”.

Aquino, M. C. (2013): Caracterizaçao química do caracol africano (Achatina (Lissachatina) fulica (Bowdich, 1822) e avaliação dos efeitos do muco cutâneo em úlceras de córnea em coelhos (Oryctolagus cuniculus). MSc. thesis, Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, 94 pp.

Aquino 2013


Modeling on Giant African Snail invasion

An Argentinan group of colleagues has elaborated the potential areas where the Giant African Snail (GAS) might occur or invade (Vogler et al., 2013). Using the same methodology as Borrero et al. (2009), they have detailed now the potential distribution areas for all South American countries. The abstract reads:

The best way to reduce problems related to invasive species is by preventing introductions into potentially susceptible areas. The purpose of this study was to create distribution models for the invasive gastropod Achatina fulica Bowdich, 1822 in South America in order to evaluate its potential geographic distribution and identify areas at potential risk. This mollusc, considered one of the 100 world’s worst invasive alien species, is the focus of intense concern due to its impact on agriculture, human health, and native fauna. We tested two commonly used ecological niche modeling methods: Genetic Algorithm for Rule-Set Prediction (GARP) and Maximum Entropy (MaxEnt). Models were run with occurrence points obtained from several sources, including the scientific literature, international databases, governmental reports and newspapers, WorldClim bioclimatic variables, and altitude. Models were evaluated with the threshold-independent Receiver Operating Characteristic (ROC) and Area Under the Curve (AUC). Both models had consistent performances with similar areas predicted as susceptible, including areas already affected and new potentially susceptible areas in both tropical and temperate regions of South America.

This new study is more detailed and much more elaborated than Borrero et al. (2009), and uses two modeling methods, (A) GARP and (B) Maxent, of which the latter is generally performing best in comparative studies. The relevance of presenting country maps for potential distribution of this species in each South American country is clear: the responsible authorities now have a handle to focus their attention to areas most under threat. Generally, the Amazon basin is most infected or theathened, but certain areas in Ecuador, Colombia and Venezuela are across the Andes but have already been invaded. The following table shows that none of the South American countries can escape to the threat of GAS, although there are gradual differences.

Borrero F.J. et al., 2009. Into the Andes. Three new introductions of Lissachatina fulica (Gastropoda, Achatinidae) and its potential distribution in South America. – Tentacle 17: 6-8.
Vogler, R.E., Beltramino, A.A., Sede, M.M., Gutiérrez Gregoric, D.E., Nuñez, V. & Rumi, A., 2013. The Giant African Snail, Achatina fulica (Gastropoda: Achatinidae): using bioclimatic models to identify South American areas suspectible to invasion. – American Malacological Bulletin 31: 39-50.

A new infection of Lissachatina fulica

The Giant African Snail, Lissachatina fulica, has set foot on the island of Cura??ao. In a just published press release, Mr Gerard van Buurt and Dr Mark Vermeij (CARMABI) announced the discovery of these snails in a garden in Oud Jan Thiel on the island. 




CARMABI is now starting investigations about the possible presence of hazardous parasite infections in the animals captured. The extent of the population also has to be established by further research.

American Malacological Society meeting

With the AMS (and COA) meetings scheduled for next week, the book with the program and abstracts for the AMS meeting is now available. Several topics of interest to Neotropical land snails are highlighted here.

Phylogenetics and evolution of Jamaican Pleurodontidae 

Makiri Sei & Gary Rosenberg

The pulmonate family Pleurodontidae (formerly placed in Camaenidae) is one of eight endemic-rich families of land snails in Jamaica. Thirty endemic Jamaican pleurodontid species are currently classified in the genera Pleurodonte, Dentellaria, Thelidomus and Eurycratera, but their evolutionary history within the family has not been rigorously examined with molecular phylogenetics. We obtained partial sequences of mitochondrial cytochrome c oxidase subunit II (COII) gene, 16S ribosomal RNA (rRNA) gene, and nuclear 28S rRNA gene from 70 Jamaican pleurodontid individuals, 24 non-Jamaican pleurodontid individuals, and twelve outgroups including Cochlicellidae, Helminthoglyptidae, Hygromiidae, Sagdidae, and Scolodontidae.

Phylogenetic analysis strongly supports the monophyly of Jamaican species and the polyphyly of the genus Pleurodonte. Jamaican Pleurodonte did not group with Pleurodonte (sensu stricto) from the Lesser Antilles, but with Dentellaria from Jamaica. These results suggest that a single colonization event with subsequent radiation established the Jamaican pleurodontid fauna. The large degree of sequence divergence within some Jamaican pleurodontid species suggests some taxa described at the varietal level need to be elevated to full species status. In addition, some supposed ingroup taxa (Caracolus, Solaropsis, Zachrysia and Parthena) grouped strongly with Jamaican Sagdidae. This suggests that Pleurodontidae is not monophyletic and that the subfamily Polydontinae might be more closely related to Sagdidae. 

Exploration at the verge of extinction ??? estimating diversity in the tropical land snail family Helicinidae (Neritopsina)

Ira Richling

Helicinids represent a family of classic tropical land snails with a distribution range limited to the subtropical and tropical zones of the New World, the Australasian and the Pacific region. Hot spots of helicinid diversity are typically found on different island sites, e. g. the Greater Antilles and certain Indo-Pacific islands.

Although not as severely threatened as other tropical land snail families such as Endodontidae, Partulidae and Achatinellidae, the Helicinidae are faced with extinction in some areas. As almost exclusively forest dwelling species with often high requirements for suitable habitats they suffer almost everywhere at least a dramatic loss of habitat. This not only results in limited available material, but highly fragmentary data on distribution, the documented range of variation etc.

Against this background, and based on case studies in the different parts of the world (Costa Rica, the Lesser Antilles, New Caledonia and Pacific islands), specific and general challenges in approaching diversity estimates are discussed. A critical review of the available data from the different regions will be presented with a new estimate of the worldwide diversity, which will help to expose poorly studied areas and highlight the main sources of new species.

In helicinids, the greatest specific drawbacks to systematic work, and thus to judging diversity, include: a limited number of recognised differentiating characters; still-questionable systematic concepts and the absence of a robust higher phylogeny, and intergrading shell morphologies and multiple cases of convergence, not only in shell shape but in radula characteristics as well. An annotated outline of the past research on Helicinidae will round off the presentation. 

Gal??pagos bulimulids: diversification amongst a vanishing tribe

Christine E. Parent

Why are island systems inhabited by remarkable adaptive radiations? Finches in Gal??pagos, Honeycreepers in Hawaii, Cichlids in the Great Lakes of East Africa–these species display a range of phenotypic variation equivalent to that of many vastly larger taxonomic groups. On Gal??pagos, bulimulid land snails have diversified to an unprecedented density of species richness. In this group there are over 70 described species representing a vast array of variation in form and ecology. This variation is the result of evolution in a fragmented landscape. Phenotypic diversity in these snails results from the combination of within-island speciation, between-island colonization and extinction.

During this talk I will first present a general overview of my research work on Gal??pagos bulimulid land snails. I will then focus on my latest work which aims at bridging the gap between the observed patterns of biodiversity at and above the species level and our understanding of how diversification proceeds at the population level. Although the patterns of adaptive radiations are increasingly well described, and the process of intraspecific diversification leading to speciation is better understood, the link between them remains to be studied in detail. 

Populations of abnormally-shelled giant African snails Lissachatina fulica (Bowdich) in Barbados

Anton Norville & Angela Fields

The giant African snail, Lissachatina fulica (Bowdich 1822), first reported from the parish of St. Michael, Barbados in 2000, is now well established in all parishes on the island.

In 2006, specimens of giant African snails possessing abnormally shaped shells were observed. A survey of the island was initiated in 2007 to document the distribution of populations of abnormally shelled (AS) snails. Collection of snails were made at 16 sites to determine the prevalence of AS-snails, the shell lengths of snails displaying shell abnormalities and the whorl at which abnormalities could first be seen. To catalogue the types of abnormality observed, 746 shells were inspected and differences from Bequaert???s description of the shell of Lissachatina fulica were noted.

Of the 78 locations surveyed, 32% were found to have populations containing abnormally shelled snails. The prevalence of AS-snails in these populations ranged from 1% to 70%. The first appearance of an abnormality could be as early as in the third whorl of a neonate shell (shell length, 9 mm) or as late as in the eighth whorl of an adult shell (shell length, 103 mm). Abnormalities found included a reflexed apex, uneven whorls, a disjunct body whorl, an umbilicus, two outer lips and a non-truncated columella.

An ereynetid mite has been found at all sites where AS-snails are present. An investigation as to whether this mite is implicated in the shell abnormalities seen in Lissachatina fulica is under way. 

Diversity, phylogeography and relationships of the Cerion (Gastropoda: Cerionidae) of the Dutch Leeward Islands

M. G. Harasewych

Long known for its exceptionally high diversity, the family Cerionidae ranges from the barrier islands of southern Florida to the Dutch Leeward Islands, usually inhabiting terrestrial vegetation with a few hundred meters of the shore. The nominotypical subgenus Cerion is restricted to the Dutch Leeward Islands, and separated from all living congeners by the Caribbean tectonic plate.

Nine taxa have been proposed for this fauna based exclusively on shell morphology. Several have been supported by subsequent, detailed morphometric analyses. Phylogenetic relationships of the subgenus and its constituent taxa are reviewed based on the first molecular studies of this fauna [partial 16S and CO I sequences]. Samples from the type localities of all named taxa are included in the analyses to infer patterns of interrelatedness among populations on Aruba, Cura??ao and Bonaire, and to evaluate biogeographic hypotheses. 

Morphological and molecular analysis of the Andean land slugs Colosius n. sp., a newly recognized pest of cultivated flowers and coffee from Colombia and Ecuador, and Colosius pulcher (Colosi, 1921) (Gastropoda: Veronicellidae).

Suzete R. Gomes, David G. Robinson, Frederick J. Zimmerman, Oscar Obregon & Norman B. Barr

In this study we identify a new species of Colosius, recognizing it as pest of coffee and cultivated flowers from Colombia and Ecuador. We compare it with C. pulcher, a species with which it has been confused. In order to analyze the genetic relationship of Colosius n. sp., C. pulcher, C. propinquus (currently synonymized with C. pulcher) and C. lugubris (type species), fragments of COI, 16S rRNA, and 28S rRNA genes are analyzed.

Genetic variability within Colosius n. sp. and C. pulcher is also analyzed based on COI and 16S rRNA. In Colosius n. sp. the phallus has a deep longitudinal groove from the base, near the retractor muscle, to its distal region, close to the papilla. In C. pulcher there is an oval to rectangular swelling on the basal region of the phallus. Some important differences between both species are also found in the digitiform gland and bursa copulatrix.

Colosius n. sp. is a distinct lineage within the genus Colosius. It is not a sister species of C. pulcher, which has C. propinquus as a sister species, here confirmed as valid. Colosius n. sp. is closer to the clade that includes C. pulcher and C. propinquus than it is to C. lugubris. Based on the phylogenetic reconstruction, C. lugubris is sister to all the other Colosius. Genetic diversity within Colosius n. sp. and C. pulcher is low.

We describe, illustrate and discuss the color variation, morphological similarities, diagnostic characters and variability, habitat and distribution for Colosius n. sp. and C. pulcher. Associated imports and number of interceptions per year of Colosius n. sp. by federal agricultural inspectors are also presented. 

Land mollusks in northern South America: biogeographic and ecological studies in megadiverse hotspots

Francisco J. Borrero & Timothy A. Pearce 

The terrestrial malacofauna of northern South America is very poorly known. As a team of Colombian, European, and USA scientists (6 institutions total) we are studying the land snails of Colombia to enhance knowledge of systematics, distribution, and phylogeography of terrestrial mollusks and to address broader questions regarding the origin and maintenance of Neotropical biotic diversity. We will assess relations of the northern South America fauna with those of North and Central America, the Caribbean, and the rest of South America. We focus on Colombia because (1) it is at the crossroads of multiple biogeographic provinces and of the inter-American faunal exchange that was facilitated by joining previously separated faunas at Panama, and (2) it includes two megadiverse hotspots (Biogeographic Choco and Northern Andes). Land snails are uniquely well suited for these analyses as they are ancient, diverse, abundant, and, due to their limited dispersal ability, they address our questions better than more mobile taxa.

We outline the rationale, main methodology, and preliminary results of this first modern, comprehensive survey program of any non-arthropod invertebrate animal group in Colombia and northern South America. A species accumulation curve for Colombia continues climbing steeply, indicating that many species remain to be described; a sharp climb since year 2000 (including work by us and others), shows that relatively little effort can markedly increase the known biodiversity.

Suitably collected material will allow us to (1) compare diversity and endemism in various ecosystems, (2) study influences of dispersal limitation and habitat specificity in snail distributions, (3) assess whether snails are as diverse as other invertebrates in leaf litter and canopies, (4) study how the American interchange of land snails differs from that of other groups, and (5) examine the contributions of in situ speciation and accumulation of fauna from other regions to Colombia???s land snail diversity. 

Therrrr Backkkk

This was the heading Harry Lee gave some days ago to his post on the Conch-L site to announce the return of Lissachatina fulica in Florida. Some religious zealot had used these snails to have his disciples swallow their juices, causing that many of them had to go to hospital for treatment.

When the media started to cover this issue, the hype began. See http://n.pr/ovmPPW. Some people now even think that all land snails are banned because they are harmful to man… One cannot be careful enough in choosing the wording of your press releases.

Today, Harry posted the following re-assuring message:

Transmission of the nematode parasite,/ Angiostrongylus cantonensis/, to
man is rare, and disease (most conspicuously eosinophilic
meningoencephalitis) even rarer. Human infection typically involves*
ingestion* of one (or more) un- or under-cooked snail. The parasite
exercises very little if any selectivity as to which amphibious or
terrestrial snail in infects in the course of its somewhat unusual life
cycle. The prominence of /Achatina fulica/ in human transmission is
essentially a function of its size and human cultural preferences. It is
likely that hundreds of snail species are naturally-infected. Among them
are /Bradybaena similaris <http://www.jaxshells.org/gallery2.htm>/ and
subulinids, e.g., <http://www.jaxshells.org/octona.htm>, which have been
introduced into the SE USA like the Giant African Snail but have spread
widely.  If it were customary for people to consume these little fellows
in areas where the parasite was present, these pulmonates would be the
culprits, and they would qualify for vilification by the Fourth Estate.

Someone, somewhere, once wrote that a person touching the mucus of an
infected snail (e.g., /Achatina fulica/) and then touching his mouth or
another mucous membrane, could allow the infective larva(e) of this
roundworm to infect him. That oft-repeated anecdote is the basis for the
rubber glove caveat. While I don’t advocate slathering uncooked snail
slime on your lips, conjunctivae, etc. in geographic areas when this
parasite occurs, reason indicates that this scenario is rank hyperbole.

A discussion of the medical geography of this parasite and the evolution
of human disease in relation to another host, apple snails, is archived
Comments on the virulence of the disease and its treatment are included.

Anyway, S.O.S. Save Our Snails. Don’t let GAS indirectly threaten native snails.