Tag Archives: Streptaxidae

Perrottetia piriformis (Pfeiffer)

Pear-shaped Perrottetia Snail (Perrottetia piriformis)

This species was described in 1859; it was endemic to the island of Rodrigues in the Mascarenes, however, its taxonomic status is not resolved.:

“Taxonomic issues arose concerning two species when they were submitted to experts, although they had never been reported as nonvalid species in the scientific literature; because their taxonomic status is unclear (the biological species designated by their names are unknown), they were classified as impossible to assess. However, due to this taxonomic uncertainty, no data are available apart from their original 19th-century descriptions, and the model evaluates them as extinct. These taxa are Coilostele acus and Perrottetia piriformis.” [1]

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The genus should not be confused with the plant genus of the same name.

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References:

[1] Claire Régnier; Guillaume Achaz; Amaury Lambert; Robert H. Cowie; Philippe Bouchet; Benoît Fontaine: Mass extinction in poorly known taxa. Proceedings of the National Academy of Sciences. 1-6. 2015

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edited: 09.11.2021

Glabrennea silhouettensis (Verdcourt)

Silhouette Glabrennea Snail (Glabrenna silhouettensis)

The Silhouette Glabrennea Snail was described in 1994, it restricted to a very small area on Mt. Dauban on the island of Silhouette, Seychelles Islands, when it was discovered in 1990.

The species apparently was an inhabitant of leaf litter.

The Silhouette Glabrennea Snail was only ever found at its type locality, once in 1990, and a for second time one year later in 1991, when its population was already declining. All subsequent searches (2000, 2009, 2010) at the type locality and other suitable areas failed to find the species again which thus is considered extinct. [1]

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References:

[1] Justin Gerlach: Red List ing reveals the true state of biodiversity: a comprehensive assessment of Seychelles biodiversity. Phesluma 20: 9-22. 2012
[2] Justin Gerlach: Changes in non-marine mollusc populations in the Seychelles islands 1986-2012. Phelsuma 20: 23-38-2012

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edited: 26.11.2018

Conturbatia crenata Gerlach

Conturbatia Snail (Conturbatia crenata)

This small snail species was described in 2001; it is known only from the Île de Frégate in the Seychelles.

The species was described after its apparent extinction; the last life individuals were seen in the year 2000 and it is believed that this species, who feeds on carrion, inadvertently fell victim to a rat eradication program that used poisoned baits to kill invasive rats.

There is, however, a slight chance that a tiny population might have survived, hidden somewhere and yet unseen.

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edited: 19.08.2022

Campolaemus perexilis Smith

Smith Saint Helena Whorl Snail (Campolaemus perexilis)  

This tiny creature, like so many other of Saint Helena’s endemic snails, fell victim to the nearly complete destruction of the native vegetation by clearings of the island’s forests for timber and fire wood, as well as by feral animals, above all by goats.  

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References:  

[1] Edgar A. Smith: On the Land-Shells of St. Helena. Proceedings of the Zoological Society of London 258-270. 1892
[2] Barna Páll-Gergely: Campolaemus Pilsbry, 1892 is not a hypselostomatid, but a streptaxid (Gastropoda: Eupulmonata). Ruthenica 30(1): 69-73. 2020

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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 25, Pupillidae (Gastrocoptinae, Vertigininae), 1918-1920′  

(public domain)

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edited: 23.05.2015

Gulella argoudi Griffiths

Argoud’s Gulella Snail (Gulella argoudi)

Argoud’s Gulella Snail was described in 2000, it is known only from subfossil remains recovered from a depth of about 10 cm in dry soil under basaltic rocks on the edge of a ravine near La Saline Les Bains on the island of Réunion, Mascarene Islands.

The shells reached sizes of about 0,37 cm in heigth. [1]

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The species is most likely extinct, however, the author while describing it, mentions the following.:

“Although described from subfossil specimens, the presence of a Gulella shell fragment (possibly belonging to this species) collected in leaflitter at Cap Noire, Dos-d’Ane Réunion, at 1300m, in 1992, suggests thius species may still survive.” [1]

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References:

[1] Owen Lee Griffiths: Nine new species of Mascarene land snails (Mollusca: Gastropoda). Molluscan Research 20(2): 37-50. 2000

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edited: 06.05.2019

Gonospira majusculus (Morelet)

Greater Gonospira Snail (Gonospira majusculus)  

The Greater Gonospira Snail from the island of Mauritius is known exclusively from subfossil shells.  

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The name is probably a synonym for some other species, since I was not able to get any information about this species so far.  

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Photo from: ‘Louis Germain: Faune malacologique terrestre et fluviatile des Iles Mascareigne. Paris 1921’  

(public domain)  

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edited: 21.03.2018

Gulella mayottensis (Connolly)

Mayotte Gulella Snail (Gulella mayottensis)  

The Mayotte Gulella Snail was described in 1885, it was endemic to the island of Mayotte in the Indian Ocean.  

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The species is commonly referred to as being extinct, however, given the fact that all other molluscan species on the island of Mayotte appear to be still alive, I personally do not know why this particular species should be extinct.  

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Depiction from: ‘A. Morelet: Malacologie des Comores. Récolte de M. Humblot a la Grande Comore. Journal de Conchyliologie 33: 288-301. 1885’  

(public domain)  

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edited: 06.05.2019

Gibbus lyonetianus (Pallas)

Purple Gibbus Snail (Gibbus lyonetianus) 

This species was described in 1780.  

The Purple Gibbus Snail was endemic to the island of Mauritius, it had a conspicuous, strangely compressed shell and probably was a predatory species.  

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It appears to have been a quite colorful species.:  

“The sole of the foot in this species is yellow; the anterior part of the upper surface varies from reddish claret to purple, and the posterior is yellow, dotted with minute purplish spots; the tentacles are dull purple.” [1]  

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References:  

[1] Geoffrey Nevill: Notes on some of the species of land Mollusca inhabiting Mauritius and the Seychelles. Proceedings of the Zoological Society of London 257-261. 1868  

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Photo from: ‘Louis Germain: Faune malacologique terrestre et fluviatile des Iles Mascareignes. Paris 1921’

(public domain) 

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edited: 06.11.2017