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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Platyhelminthes |
Order: | Tricladida |
Family: | Geoplanidae |
Genus: | Australoplana |
Species: | A. sanguinea
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Binomial name | |
Australoplana sanguinea (Moseley, 1877)
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Synonyms | |
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Australoplana sanguinea (Moseley, 1877), more commonly referred to as the Australian Flatworm, is found in Australia and New Zealand and is invasive in England and Northern Ireland. It is a species of flatworm that predates on Lumbricina (Earthworms). It currently has two subspecies recognized.
Description:
editA. sanguinea is part of the genus Geoplanidae, more commonly referred to as land planarians/flatworms.
When their soft, unsegmented body is stretched, broadly out curved dorsally and flattened ventrally, A. sanguines creeping sole is only covering about 25% of their body width[1]. The creeping sole is a heavily ciliated area on the ventral epidermis, which it uses as its form of locomotion. It can be up to 80mm long (at rest, less than half that) and 4mm wide, with a blunt posterior and a tapered anterior. Across the species, dorsal coloring is varying, with it ranging from a pale yellow-orange, to dull pinkish-orange, to greyish-pink, to a pale brown. With the possibility of the anterior epidermis being tinged in a pink-to-red hue. The ventral can be slightly paler than the dorsal. With its small and numerous eyes forming a continual line around the anterior tip and extending posteriorly, being more concentrated at the head apex. With the mouth being located on the posterior third of the body, ventrally[2]. They are Acoelomates, which mean that they lack a fluid-filled body cavity, used for separating digestive track from the body wall. This restricts them to be flat and thin enough as to be able to diffuse oxygen and nutrients, but having the danger of internal organs being easily crushed. [3]
Distribution:
editFound in Australia, Europe and New Zealand where it has been found in the South Island (and North Island with only a few records), predominantly Christchurch, where a population was accidentally introduced into an Alexandra, New Zealand through trading of plant material from horticultural sites. This is the same method that let A. sanguinea have far reaching accidental introduction into Europe where it can be found in the Isle of Man, Isles of Scilly, Dorset, and especially south-west England and Northern Ireland (first identified in Belfast, 1974)[4][2]. In these regions it can be found habiting gardens, garden centers, farms and parks (usually nocturnally) where they lie underneath objects on the soil surface, especially containers, stones, logs, and tarps[2]. It is presumed that soil moisture is an important factor in the amount and location of A. sanguinea.[5]
Life Cycle:
editIn mature flatworms, developing eggs are noticeable as bulges on the midline, and when laid in soil, the egg capsules are proportionately smaller than those of relative species, such as the New Zealand flatworm Arthurdendyus triangulatus.[6] They are dull and red at first, but within a few hours, the egg's chitin cures a shiny black. After a few weeks, when the eggs hatch, the juveniles are smaller, paler versions of the parents[2]. Studies have shown that the flatworms prefer wetter times of the year, and so adults are less likely to be found during summer months, as they usually retreat into the soil during this time[7]. They are hermaphrodites, though whether it reproduces sexually by cross-fertilization or self-fertilization is unknown. A lack of eggs being found over in Europe suggests to us that fission may be a means of reproduction.[7][1]
Predations:
editA. sanguinea are obligate predators of Lumbricina and have had impacts on earthworm populations since its introduction into Europe, but not as much as in New Zealand, where it may because they are still confined in restricted, specialized habitats.[4] While they are not as successful and are slower at attacking earthworms than other planarians such as the New Zealand flatworm, they still impact the population. It has been suggested that flatworms and earthworms are able to co-exist in places, such as New Zealand, where they have found most of the endogeic and half of the epigeic species of flatworms in close proximity to flatworms, but none of the anecic species.[5] This may be affected by climate, where colder and moister conditions seem to be more positive for flatworm reproduction and survival.[7]
References
edit- ^ a b Victoria, Field Naturalists' Club of; Barnard, F. G. A.; Lucas, A. H. S.; Victoria, Field Naturalists' Club of; Victoria, Field Naturalists' Club of (1991). "The Victorian Naturalist". 108. Field Naturalists Club of Victoria.
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(help) - ^ a b c d Mather, Janice G.; Christensen, Ole M. (August 1996). The land planarian Australoplana sanguinea var. alba at a horticultural site in New Zealand. Annals of Applied Biology. pp. 171–179.
- ^ Invertebrate zoology (2nd ed.). Melbourne: Oxford University Press. 2001. ISBN 978-0-19-551368-4..
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value: invalid character (help) - ^ a b Yeates, G. W.; Boag, B.; Johns, P. M. (1997). "Observations on feeding and population structure of five New Zealand terrestrial planarians which prey on lumbricid earthworms". Annals of Applied Biology. pp. 351–358. doi:10.1111/j.1744-7348.1997.tb05161.x.
- ^ a b Fraser, P.M; Boag, B. (20 April 1998). "The distribution of lumbricid earthworm communities in relation to flatworms: a comparison between New Zealand and Europe" (PDF).
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(help) - ^ McDowell, S. D. R. Reproduction and survival of invading flatworms, with emphasis on the ‘Australian flatworm’ Australoplana sanguinea var. alba. Ph.D. Thesis, The Queens University of Belfast.
- ^ a b c Jones, Hugh D.; Green, James; Harrison, Kathryn; Palin, Douglas W. (April 2001). "Further monthly records (1994 to 2000) of size and abundance in population of the "Australian" flatworm, Australoplana sanguinea alba in the U.K" (PDF). Belgian journal of zoology.