Archachatina ventricosa :
Other Species :
- Archachatina land snails
Archachatina marginata :
courtesy to : en.wikipedia.org/wiki/Archachatina_marginata
Archachatina marginata, common name the giant West African snail or banana rasp snail, is a species of air-breathing tropical land snail, a terrestrial pulmonategastropod mollusk in the family Achatinidae. They can grow up to 20 cm long, and live up to 10 years.
The shell of Archachatina marginata
Scientific classification :
Kingdom:Animalia
Phylum:Mollusca
Class:Gastropoda
(unranked):clade Heterobranchia
clade Euthyneura
clade Panpulmonata
clade Eupulmonata
cladeStylommatophora
informal groupSigmurethra
Superfamily:Achatinoidea
Family:Achatinidae
Genus:Archachatina
Species:A. marginata
Archachatina marginata
(Swainson, 1821)
Distribution
This species occurs in Western Africa: Cameroon through Democratic Republic of the Congo, and can be found in the Caribbean, in Martinique.[1]
How the species reached Martinique is unknown, but it is possible they were intentionally introduced as "pets" or by workers returning from West Africa.[2]
The natural spread of this species is very slow; however, unintentional spread by individuals for food and as folk medicine is very common.[3] The USDA routinely checks for the species in the luggage of travelers from West Africa, Nigeria particularly, Ghana and Cameroon.
This species has not yet become established in the United States, but it is considered to represent a potentially serious threat as a pest, an invasive species which could negatively affect agriculture, natural ecosystems, human health or commerce. Therefore it has been suggested that this species be given top national quarantine significance in the United States.[4]
Description :
The snail has a bulbous protoconch that is large and broad, with a white or bluish-white columella, parietal wall and outer lip. The shell of the snail can grow up to 21 centimeters in height, and 13 centimeters in diameter. The shell, when magnified, has the appearance of a woven texture.[5]
Invasive species :
The snail feeds on a large variety of plants, mainly fruits. Plants included in the snail's diet are bananas, lettuce, peanuts, and peas, some of which are important crops in certain economies.[6] The giant West African snail is one of the worst invasive species in the world and is extremely devastating to any species that it affects. However, the more prevalent problem with the spread of the snail as an invasive species is that it is often a carrier of the disease rat lungworm. Within humans this causes the disease eosinophilic meningoencephalitis, which is what makes the snails' spread to North America problematic. If the snails continues to spread it could potentially be a problem for the health of people all throughout North America from Cuba to the United States.[7] Archachatina marginata can live up to 10 years, and attain sexual maturity at 9–10 months under laboratory conditions. In addition to being an agricultural pest, they act as the reservoir host of rat lung parasites which cause eosinophilic meningoencephalitis in humans and are seen as a threat to public health because of this.[8]
Ecology :
Achatinids are nocturnal forest dwellers but can adapt to disturbed habitats. The snails prefer concealed habitats and if overcrowding occurs, they may colonize more open habitats. During periods of high humidity, Achatinids are more active but if the individuals are found during broad daylight it is most likely due to high population density.
Eggs of Achatinids are normally laid in the soil, but can be found under leaves or rocks. They produce as many as 40 eggs which are yellow in color with dark blotches and an incubation period of approximately 40 days.
Mating :
Mating for the Archachatina marginata species varies in the three separate states of Nigeria: Enugu, Edo, and River. The rate of snail mating across the three states is low at 20 percent because most A. marginata snails have homotypes rather than heterotypes. As a result, the reproductive rate for A. marginata is relatively slow.[9]
In pre-mating process, one A. marginita attempts to exhibit mating behavior while another A. marginita must respond positively in order to proceed with mating. In wet season (from March), A. marginita begin their reproductive process. After the A. marginita baby hatches, it usually takes up to four weeks for the growing traits to develop. During the first few weeks of life, the A. mariginita eats less than an adult due to the slow process of gaining weight.[10]
Archachatina marginata var. ovum(Pfeiffer, 1858)
Archachatina marginata var.suturalis (Philippi, 1849)
Diet :
Wild snails eat plants at a ferocious rate.[clarification needed] Often times this leads to property destruction and damage to homes. Studies have shown that the snails will eat during the day but they prefer to eat at night. Wild snails have a very wide appetite on a whole and they are known to eat up to 500 different species of plants. Snails that have become domesticated typically consume food that is high in protein and low in fats. Studies from 2005 that were done to test food on domesticated snails have shown that poultry droppings have been the most effective meal to both grow and gain weight.[11]
Nervous system :
In this organism's nervous system, there are two main types of nerves: pallial nerves and visceral nerves. Pallial nerves are the subject of the majority of scientific research. Visceral nerves are split into two subcategories: the main visceral nerve and the rectal visceral nerve. The main visceral nerve is on the snail's back and connects to a large group of nerve cells to transmit information in the body. The rectal visceral nerve starts further down under the main visceral and extends a short length before branching off near the rectum.[12]
Heat can stimulate reactions in the West African snail as a result of the snail's nervous system. The nerves produce warm responsive fibers when the temperature exceeds 25°C and produce cold responsive fibers when the temperature falls below 19° C. The ideal temperature range for this species falls between 13° and 32° C; this is also formally known as the thermopreferendum of the species.[13]
Subspecies :
Archachatina marginata var. Ovum
Archachatina marginata var. Suturalis
Archachatina marginata var. Egregia
Archachatina marginata var. Eduardi
Archachatina marginata var.Candefacta
Archachatina marginata var. Grevillei
Archachatina marginata var. Icterica
Archachatina marginata var. Ovum
Archachatina marginata var. Egregia
Archachatina marginata var. Grevillei
Archachatina (Calachatina) marginata (Swainson, 1821)
courtesy to : www.petsnails.co.uk/species/archachatina-marginata
West African Land Snail, Banana Rasp Snail, "Margie"
Archachatina marginata is the largest of the Archachatina snails and is found in West Africa. It appears to be a mainly terrestrial snail. In Cameroon it can be found aestivating under ground during the drier months, having a closed aperture, sealed with a solid, calcareous, white epiphragm.
It is to be noted that when a crawling snail is disturbed it produces a peculiar screaming noise, caused by the expulsion of air as the shell is rapidly retracting by the powerful columella muscle.
Natively, this species does not cause any appreciable damage to native crops and is actually considered an economic asset among many native peoples who include it in their diet. In many parts of West Africa, it is considered the second best snail to eat after Achatina achatina. They have been known to stow away on banana shipments and make it to Germany (Boettger, 1938).
An albino-bodied form can be found and is actually becoming more common. This is because natives prefer to eat the dark-skinned ones, based on the belief that they are tastier and that there is something undesirable or freakish about the white-skinned ones.
It must be noted that in captivity, it is known that captive snails tend to be lighter than their wild counterparts and this is not the same thing.2
The shells of Archachatina marginata are used for domestic purposes by locals for salt holders and cups etc.
"A. marginata has evidently been dispersed by human agencies in West Africa, having recently invaded the south-west parts of Ghana (Monney, 1994). It has also been introduced to Annobón and São Tomé in the Gulf of Guinea (Gascoigne, 1994). OnSão Tomé it has become widespread and Gascoigne (1994) suggested that competitive interactions, along with habitat destruction, may have contributed to the decline in the indigenous Archachatina bicarinata (Bruguière)." 1
Identification :
Archachatina have a raised V ridge on their tail that you can feel clearly if you run a wet finger over it. For more information on this see the Achatinidae Identification guide.
You'll also find the snail's skin to be more finely textured than Achatina, although this is less apparent near the tail. Unfortunately this can't tell you what type of Archachatina you have but it is the first step.
In addition to geographic locale, there are two main features distinguish the several variations of Archachatina marginata from the related members of the genus:
"The first is the subsutural, usually strongly marked engraved line, separated from the suture by a low narrow depressed area covered with irregular, low, vertical folds, the suture itself being straight or very slightly wavy, not crenulate. The engraved line starts on the fourth and fifth whorl and it is often deep and prominent, particularly on the body-whorl; but occasionally it is weak or almost lacking, especially in subsp. eduardi Pilsbry. The second feature is a peculiar microsculpture of the body-whorl, only visible with the proper magnification. It consists of numerous extremely fine, close-set, criss-cross or anatomising lines, making the surface of the periostracum look as if it had been pressed with a very finely woven cloth. This "weave" type of microsculpture is more pronounced in some forms or races than in others. It is particularly conspicuous when the periostracum is well developed and preserved, as is more common in some of the Cameroon races, such as subsp. egregia. In old shells, even when taken alive, the microsculpture is sometimes almost completely worn off, but traces of it may generally be detected in a few spots. The nepionic whorls, when well preserved, as in newly hatched or very young shells, are densely covered with regular spiral and vertical rows of minute granulations, which become coarser on the first, post-nepionic whorl." Studies in the Achatininae, a group of African land snails - Joseph C. Bequaert, 1950., p.140-141.
Archachatina marginata var.marginata (Note the Bluish-white columella, as shell pattern is not reliable at all).
Archachatina marginata var. ovum(Note the apricot columella, as shell pattern is not reliable at all).
Care:
Conditions in the general care guide are ample, but it should be noted that Archachatina prefer conditions much steadier, and perhaps a little wetter than average.
Archachatina marginata var.suturalis(Note the vinaceous columella, as shell pattern is not reliable at all).
Breeding :
Average longevity is about 4½ years. Early death may occur in the third year, most deaths between 4 and 5 years. A few individuals may survive to 7½ years and occasionally 10 years.
Young snails can show signs of sexual maturity at 9-10 months old; prominent genital opening and interest in other snails. The eggs are on average 20 mm. long (range 10.6 - 25.1 mm.) and the average width was 15.7 mm. The size of the eggs is directly related to the size of the snail. The average clutch size is about 8-9 eggs with 3 being a minimum and 16 being a maximum. Sometimes single infertile eggs are laid on the surface. Each animal can lay between 2-4 clutches per season. It would also seem that in captivity in the UK, with no seasonal variation control they show a major peak in egg-laying between May and June and a minor peak during September. It has been hypothesised that if that is a reflection of the wild (Nigeria), the snail would hatch at the beginning of the wet season, meaning the babies have a better chance of survival.
The development of the embryo is heavily affected by soil temperature and moisture. The best conditions seem to be in very damp soil at a temperature of 23°C. The variations in temperature are responsible for many embryonic deaths. At an air temperature of 26-28°C and an inch below the soil surface 17-19° the incubation time is 35-41 days. At an air temperature of 26-28°C and a soil temperature at 22.5-23°C incubation time is 29-35 days.
The hatchlings consume their own egg shell and then start eating their siblings shells. Usually one of the upper eggs hatches first followed, in the next 24 hours, by a second hatching in a similar position. The first one to hatch may take 24-36 hours to do so. All the viable eggs usually hatch within a week of the first.
The young snail tend to burrow underground for at least 7 days but this can be 10-14 days.2
Further Reading:
- Life of Achatinidae in London (Nisbet, 1974)
- Gallery
- Impact on Tropical Agriculture
Sources :
Much of the information on this page was sourced of paraphrased from: Studies in the Achatininae. J. C. Bequaert., 1950.
Some Videos :
Giant land snail Archachatina marginata var. ovum baby
How to care for Giant Snails - Hibernation - Archachatina marginata
Giant land snail Archachatina Marginata Suturalis eating
Other Types of Archachatina species :
Archachatina (Calachatina) degneri (Bequaert and Clench, 1936):
Giant Gold Coast Snail :
Often and easily confused with Archachatina puylaepti. According to A. Mead it is indistinguishable externally and requires analysis of the sexual organs to make the distinction.
Identification :
Originally described as follows from one specimen (not Bequaert):
"Shell solid, subovate, imperforate and somewhat shiny. Color: first three and a half whorls uniformly light brownish-yellow; following two whorls barred with irregular reddish-brown axial streaks which overlie the light brownish-yellow ground color; the reddish-brown color bars continue to the aperture, but the ground color changes from brownish-yellow to a decided light greenish-brown. On the last two whorls there appear to be upon close inspection a series of faint grayish, very fine zigzag lines, arranged more or less axially. Entire interior area of aperture, columella and parietal callus a deep vinaceous-red (Ridgway's pomegranate purple); extreme inner edge of outerlip and outer margin of parietal greyish purple. Whorls 7, convex, the last two impressed somewhat below the suture. Spire somewhat extended, produced at an angle of 60�. Body whorl about 77% of the total shell. Aperture rounded-ovate, about 65% of length of the shell, widest below the middle. Palatal lip flaring, bell-like, slightly thickened. Columella rather wide and twisted within, nearly straight and rather abruptly and broadly truncate. Sculpture: first one and a half whorls minutely rugose, gradually merging into the distinct, but very fine, decussate sculpture of the next three and a half whorls; on the remaining whorls the sculpture becomes irregular and the beading is only very faintly indicated; body-whorl roughened somewhat by coarse growth-lines."
More about the inside of the lip (Bequaert):
"In the holotype, the columella, parietal wall, inner margin of outer lip (except for the narrow edge) and the entire inside of the aperture to far back in the shell are a gorgeous deep vinaceous-red. This is true also for a few shells I have collected in the Gold Coast. More often, however, the inside is reddish, in varying shades from orange-red to violaceous only near the outer-lip over a width of an inch or less. All transitions may be observed between these two extremes."
The data is limited, but the difference between degneri and marginata is....
"...These shells could only have been degneri, even though the species is known to occur in Gaboon, so that the locality should be regarded as erroneous. A. marginata which exists in Gaboon, is ruled out, first because Shuttleworth uses it for comparison; secondly because he mentions no difference in color from his polyphyrostoma, so that his shells must have been extensively purplish inside the aperture, a character not found in any of the several forms of marginata with which I am acquainted..."
Archachatina degneri var. degneri
Archachatina bicarinata
Archachatina camerunensis :
Archachatina crawfordi
Archachatina dimidiata
(E. A. Smith, 1878)
Divided Agate Snail
Archachatina dimidiata var. dimidiata
(Picture Courtesy of the British Natural History Musueum)
Archachatina granulata
Archachatina knorrii
Archachatina limitanea
Archachatina limitanea shell
Archachatina ustulata
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Due to the large quantity of land snails species and the new yearly discoveries we will shortlisted the famous and most colorful and strange shape of these creatures . yet this hobby is challenging for the most of hobbyists ..