Powelliphanta hochstetteri
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Powelliphanta hochstetteri , Rameka Track, Golden Bay |
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| Powelliphanta hochstetteri | ||||||||||||
| ( Pfeiffer , 1862) |
Powelliphanta hochstetteri ( synonym : Paryphanta hochstetteri ) is the name of a predatory living snail from the family Rhytididae in the subordination of terrestrial snails (gastropod), which in New Zealand is widespread.
features
Powelliphanta hochstetteri has a firm, moderately open naveled, flattened, irregularly wrinkled, slightly shiny, red-yellow or greenish-brownish snail shell with a dark brown outer band with impressed, dense spiral lines. The thread protrudes only a little and has a blunt vortex. The house of the adult snail has five and a half moderately arched and rapidly increasing coils, the last being more arched and compressed. There is a wide dark zone around the navel. The very oblique and broadly elliptical case mouth is strongly cut out. The blunt muzzle, the edges of which are connected by a whitish callus, is covered by the strong periostracum . The shell of the adult snail reaches an average diameter of 56 mm and 65 mm and a height of 28 mm. Depending on the subspecies, case sizes of up to 80 mm at a height of 35 mm have also been measured.
The central tooth of the radula is smaller than the neighboring, internal posterior teeth. The number of teeth on either side of the transverse rows on the radula of Powelliphanta hochstetteri varies between 59 and 67.
Distribution and occurrence
Powelliphanta hochstetteri is endemic to the provinces of Marlborough and Nelson on New Zealand's South Island . The snail can be found in the highlands at an altitude of 750 to over 1200 meters above sea level under leaf litter and rotting wood in damp forests, especially with the pseudo beech species Nothofagus menziesii and Nothofagus fusca . It is dependent on humid climates.
Life cycle
Like other species of the genus Powelliphanta , the snails can live up to 20 years and reach sexual maturity at around 5 years. The hermaphrodites fertilize each other and then lay around 10 eggs. The oval eggs vary in size, moving around 12mm by 10mm.
nutrition
Like other snails of the genus Powelliphanta , Powelliphanta hochstetteri prefers earthworms as prey, which are grasped with the radula and crushed in the foregut with the radula teeth.
Predators and threats
As with other Powelliphanta species, the main enemies of Powelliphanta hochstetteri are predatory mammals , which have led to a rapid decline in populations. The most dangerous predator is the imported climbing bag Trichosurus vulpecula , which eats all stages of development of the snail, but also pigs , hedgehogs and rats . Among the birds, song thrushes that have been introduced hunt young snails, while the native Wekaralle ( Gallirallus australis ) only occasionally plays an important role in snail mortality today. Further factors are the deforestation of the forests, especially for the production of agricultural land, as well as the destruction of the habitat through browsing or being represented by imported goats , cattle and deer .
Initial description
Powelliphanta hochstetteri was first described in 1862 by the German malacologist Ludwig Karl Georg Pfeiffer under the name Helix hochstetteri . The basis for the description was solely the snail shell that the German geologist Ferdinand von Hochstetter had brought to Germany from New Zealand. Ferdinand von Hochstetter is honored with the specific epithet hochstetteri . For a long time - until Powelliphanta was raised to its own genus - the species was placed as Paryphanta hochstetteri in the genus Paryphanta first described by Johann Friedrich Hermann Albers in 1850 .
Subspecies
There are 5 subspecies:
- Powelliphanta hochstetteri hochstetteri ( Pfeiffer , 1862) has a case diameter of around 75 mm and a height of 35 mm. The house has many irregular stripes, bands or zones (except at the navel) on a khaki to gold background. It lives on the upper reaches of the Takaka River on the Pikikiruna , northern Arthur Range , Lockett Range , Cobb Ridge in Kahurangi and in the Abel Tasman National Park in northwest Nelson at altitudes of 750 to 1200 meters above sea level in forests with Nothofagus menziesii and Nothofagus fusca , occasionally with Metrosideros umbellata and Libocedrus spp. About 50% of the subspecies habitat is found on calcareous soils over marble . The main threats come from imported climbing baglers, pigs and deforestation.
- Powelliphanta hochstetteri anatokiensis Powell , 1938 has a case diameter of around 80 mm and a height of 35 mm. The house has a pattern of tightly arranged, diffuse, reddish brown to black spiral lines and bands on a reddish brown to yellow background. It lives on the upper reaches of the Anatoki River, on the Yuletide Peak Ridge and on the river plain opposite the Anatoki Forks Hut in smaller numbers down the river to The Bend at heights of 760 to 1050 meters above sea level below Gahnia spp. and Microlaena avenacea in forests with Nothofagus menziesii , Nothofagus fusca , Phyllocladus alpinus and Dracophyllum traversii , the yellow form on the eastern mountains of Devil Range , Anatoki Range and Walker Ridge as well as on the ridge between the rivers Waikoropupu and Pariwhaka in , unter Kalkstein Forests of Nothofagus menziesii , Nothofagus fusca , Metrosideros umbellata , Libocedrus bidwillii and Dracophyllum traversii . The main endangerment comes primarily from imported climbing baglers, but also from pigs.
- Powelliphanta hochstetteri bicolor Powell , 1930 has a case diameter of around 70 mm and a height of 32 mm. The very flattened house with a low apex has few irregular spiral lines at the edge on a light yellowish olive-colored to almost black background, while the base is free of spiral lines, but there is always a circular zone with a dark chocolate-brown color in and around the navel. It lives in the eastern Marlborough Sounds including Mount Stokes , Mount Cullen, and on the peaks west of Picton from Mount Robertson to Kahikatea and Arapawa Island, and from sea level to the summit on Blumine Island in forests with Dysoxylum spectabile , Beilschmiedia tawa , Rhopalostylis sapida , Leptospermum scoparium and Pseudopanax arboreus . The main threats come from deforestation for agriculture, introduced pigs, climbing baggers, song thrushes and habitat destruction by goats.
- Powelliphanta hochstetteri consobrina Powell , 1936 has a case diameter of around 63 mm and a height of 27.5 mm. The house usually has a smooth surface, but there are sometimes a few narrow black spiral lines. The basic color is reddish yellow, and at the base there is a dark reddish brown zone from the navel to halfway to the periphery. It lives in a relatively large area in the mountains between the Waimea and Wairau rivers in eastern Nelson , on the Richmond Range between Grass Knob and Mount Baldy and on the Bryant Range between Mount Starveall and Trig 16 north of Mount Duppa at heights of 884 to 1280 meters above sea level under leaf litter and Chionochloa spp. in forests with Nothofagus solandri , Nothofagus menziesii , individual Phyllocladus alpinus , Libocedrus bidwillii and Metrosideros umbellata , mostly on slate . The main threats come from deforestation, destruction of the habitat by imported goats and deer as well as from the introduced pigs, climbing baglers, song thrushes and rats.
- Powelliphanta hochstetteri obscura Beutler, 1901 has a case diameter of around 70 mm and a height of 39 mm. The house has brown spiral lines on a uniformly dark brown to almost black background and a green-brown to yellowish olive upper color. She lives in the western Marlborough Sounds as well as on D'Urville Island and Maud Island , formerly on Stephens Island and Emslie Bay in French Pass at heights of 600 meters above sea level, but occasionally down to sea level, for example in Matai Bay in a forest with Griselinia littoralis , Nothofagus spp. and Podocarpus spp. The main threats come from introduced pigs, climbing baglers, song thrushes, rats and deforestation.
Trivia
Like other species of the genera Powelliphanta and Paryphanta , the snails in New Zealand are known as kauri snails or pupurangi .
Web links
Individual evidence
- ^ A b Ludwig Karl Georg Pfeiffer (1862): Diagnoses of some land snails from New Zealand. Malakozoologische Blätter 8 , pp. 146-150.
- ^ O. von Möllendorff: Agnatha Moerch. Predator snails. 2. Genus Paryphanta Alb. , 2. Paryphanta hochstetteri, p. 11f. In: O. von Moellendorff and Wilhelm Kobelt: Die Raublungenschnecken (Agnatha). Systematic Conchylia Cabinet by Martini and Chemnitz. Verlag von Bauer and Raspe (Emil Küster), Nuremberg 1905.
- ↑ a b c d e Kath Walker: Recovery plans for Powelliphanta land snails 2003-2013. Threatened Species Recovery Plan 49, 3. The recovery plans. Pp. 44-61.
- ^ Gary M. Barker and Murray G. Efford: Predatory Gastropods as Natural Enemies of Terrestrial Gastropods and Other Invertebrates. In: Gary M. Barker (Ed.): Natural Enemies of Terrestrial Molluscs. CABI, Wallingford (UK) 2004. pp. 279-404, here p. 342.
- ^ AC O'Connor (1945): Notes on the Eggs of New Zealand Paryphantidae, With Description of a New Subgenus. Transactions of the Royal Society of New Zealand 5 (1945-1946), p 54 -57.
- ^ Arthur William Baden Powell : New Zealand Mollusca . William Collins Publishers Ltd, Auckland 1979. ISBN 0-00-216906-1
- ↑ Kauri Snails. Department of Conservation (New Zealand) .