Ogasawaran Mandarina Snail (Mandarina ogasawarana)
This species was described in 1999, it is known exclusively from Holocene deposits at Nankinhama on southern Hahajima Island, Ogasawara Islands, Japan.
The Ogasawaran Mandarina Snail was a medium-sized member of its genus, reaching average shell heigths of about 2 cm, they were characterized by a flat spire and a relatively large body whorl with a weak peripheral angulation and other characters.
The species disappeared at around 2000 BCE, most likely because of environmental changes due to natural climatic changes that resulted in a rise of temperatures creating a dryer climate. [1]
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References:
[1] Satoshi Chiba: A new species of land snail of the genus Mandarina (Gastropoda: Pulmonata) from Hahajima of the Bonin Islands, Western Pacific: a species that became extinct after 2000 yr. B.P.. Bulletin of the National Science Museum (C) 25(3-4): 121–127. 1999
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edited: 19.04.2019
Tag Archives: Mandarina
Mandarina titan Chiba
Giant Mandarina Snail (Mandarina titan)
This species was described in 1989 based on fossil and subfossil material that had been collected from the fissure deposits of Minamijima Island, Ogasawara Islands, Japan. [1]
The Giant Mandarina Snail was indeed a giant, its shells reached sizes of up to nearly 7 to 8 cm in diameter, making it the largest land snail species of the Ogasawara Islands and also of Japan. [2]
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The species first appeared about 13000 BCE and finally disappeares from the deposits at around 8000 BCE in the early Holocene, it disappeared due to natural environmental changes. [1]
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References:
[1] Satoshi Chiba: Taxonomy and morphologic diversity of Mandarina (Pulmonata) in the Bonin Islands. Transactions and Proceedings – Palaeontological Society of Japan 155: 218-251. 1989
[2] Satoshi Chiba: Taxonomic revision of the fossil land snail species of the genus Mandarina in the Ogasawara Islands. Paleontological Research 11(4): 317-329. 2007
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edited: 19.04.2019
Mandarina pallasiana (Pfeiffer)
Pallas Mandarina (Mandarina pallasiana)
This species was described in 1850, it is known from subfossil specimens that were recovered from Holocene deposits at the Kominato Beach on southern Chichijima Island, Ogasawara Islands, Japan.
The shells are quite large, some are white and bear two to four brown bands, some are unicolored brown without bands. [1]
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The species was for some time thought to be identical with the Minamizaki Mandarina Snail. [1]
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The Pallas Mandarina died out because of natural climatic changes that lead to a rise of the temperatures making the habitat becoming dryer.
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References:
[1] Satoshi Chiba: Taxonomic revision of the fossil land snail species of the genus Mandarina in the Ogasawara Islands. Paleontological Research 11(4): 317-329. 2007
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edited: 19.04.2019