Tag Archives: Diplommatinidae

Plectostoma tenggekensis Liew, Vermeulen, Marzuki & Schilthuizen

Tenggek Karst Snail (Plectostoma tenggekensis)

The Tenggek Karst Snail was described in 2014; it is only known from the type locality: Bukit Tenggek in Pahang, central Peninsular Malaysia.

The shells reach sizes of 0.16 to 0.17 cm in height; the apical spire is depressed, the basal spire is conical and the whorl periphery is moderately convex, the umbilicus is open.

The only known locality where this species was known to occur, is now completely destroyed by limestone quarrying.

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Photo from: ‘Thor-Seng Liew; Jaap Jan Vermeulen; Mohammad Effendi bin Marzuki; Menno Schilthuizen: A cybertaxonomic revision of the micro-landsnail genus Plectostoma Adam (Mollusca, Caenogastropoda, Diplommatinidae), from Peninsular Malaysia, Sumatra and Indochina. ZooKeys 393: 1-107. 2014’

https://creativecommons.org/licenses/by/4.0/

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References:

[1] Thor-Seng Liew; Jaap Jan Vermeulen; Mohammad Effendi bin Marzuki; Menno Schilthuizen: A cybertaxonomic revision of the micro-landsnail genus Plectostoma Adam (Mollusca, Caenogastropoda, Diplommatinidae), from Peninsular Malaysia, Sumatra and Indochina. ZooKeys 393: 1-107. 2014

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edited: 01.03.2024

Plectostoma charasense (Tomlin)

Charas Karst Snail (Plectostoma charasense)

This species was described in 1948; it was known from only two localities: Bukit Panching and Gua Charas, two neighboring limestone hills near Sungai Lembing in Pahang, central Peninsular Malaysia.

The shells reach sizes of only about 0.19 to 0.2 cm in height; the apical spire is oblong conical, the basal spire is conical and the whorl periphery is distinctly convex, the umbilicus is open.

Bukit Panching has been destroyed by limestone quarrying and Gua Charas is now surrounded by oil palm plantations, leaving only traces of the former forest cover; the species has not been found during exhaustive searches in 2010 and 2011 and is very likely extinct.

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Many congeneric species are strictly restricted to single localities and very likely many of them are now likewise extinct due to the complete destruction of their habitats.

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Photo from: ‘Thor-Seng Liew; Jaap Jan Vermeulen; Mohammad Effendi bin Marzuki; Menno Schilthuizen: A cybertaxonomic revision of the micro-landsnail genus Plectostoma Adam (Mollusca, Caenogastropoda, Diplommatinidae), from Peninsular Malaysia, Sumatra and Indochina. ZooKeys 393: 1-107. 2014’

https://creativecommons.org/licenses/by/4.0/

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References:

[1] Thor-Seng Liew; Jaap Jan Vermeulen; Mohammad Effendi bin Marzuki; Menno Schilthuizen: A cybertaxonomic revision of the micro-landsnail genus Plectostoma Adam (Mollusca, Caenogastropoda, Diplommatinidae), from Peninsular Malaysia, Sumatra and Indochina. ZooKeys 393: 1-107. 2014

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edited: 01.03.2024

Opisthostoma decrespignyi H. Adams

De Crespigny’s Karst Snail (Opisthostoma decrespignyi)  

This minute species, whose shell hardly reaches 0,2 cm, was described in the year 1865.  

De Crespigny’s Karst Snail inhabited small islets like Pulau Burung, Pulau Daat, and Pulau Papan offshore the island state of Labuan, which again lies offshore Borneo’s northwest coast, where it was strictly restricted to limestone rocks.  

The limestone (of all these islands ?) was removed in the 1960s by quarrying, and thus the habitat of this snail species was destroyed. [1]  

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De Crespigny’s Karst Snail is now considered possibly extinct – however, there have been no recent surveys to confirm this assumption.  

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References:  
[1] Reuben Clements; Navjot S. Sodhi; Menno Schilthuizen; Peter K. L. Ng: Limestone Karsts of Southeast Asia: Imperiled Arks of Biodiversity. BioScience 56(9): 733-742. 2006 

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Depiction from: ‘Henry Adams: Descriptions of Six New Species of Shells, and Note on Opisthostoma de-Crespignii. Proceedings of the Zoological Society of London. 445-451. 1866’

(public domain)

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edited: 04.11.2020

Opisthostoma otostoma Boettger

Brunei Karst Snail (Opisthostoma otostoma)  

This species was described in 1893, it occurred in a single locality on limestone outcrops in lowland tropical Dipterocarp rainforest on limestone.  

The shell reached an average size of about 0,25 cm in diameter.  

The only place where this snail existed is now an airport, the habitat of the snail does not exist anymore.  

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References:  

[1] Reuben Clements; Navjot S. Sodhi; Menno Schilthuizen; Peter K. L. Ng: Limestone Karsts of Southeast Asia: Imperiled Arks of Biodiversity. BioScience 56(9): 733-742. 2006  

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Depiction from: ‘E. A. Smith: On a Collection of Land-Shells from Sarawak, British North Borneo, Palawan, and other neighbouring Islands. Proceedings of the Zoological Society of London. 79-127. 1895’ 

(public domain)

Depiction from: ‘E. A. Smith: On a Collection of Land-Shells from Sarawak, British North Borneo, Palawan, and other neighbouring Islands. Proceedings of the Zoological Society of London. 79-127. 1895’  

(public domain)

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edited: 04.11.2020