Photo of the day (69): Vitrina pellucida

Vitrina pellucida is a small land snail in the family Vitrinidae. It is widely distributed in the Holarctic and it is very common species.

There is visible mantle appendix (extension of the mantle that slightly cover the shell) and open pneumostome (breathing pore) on the photo:

Vitrina pellucidaYou can find them in autumn much more easily. They are fully grown up to 10 mm in body length in autumn. Then they will lay eggs and die. The next generation will hatch out from eggs at spring. Therefore you can not usually find adult Vitrina pellucida at (late) spring (depending on country).

I was mushroom hunting in Moravia on October 14, 2017. I found this snail altogether with two juvenile Lehmannia marginata slugs on a Xerocomellus chrysenteron mushroom.

Vitrina pellucida and two Lehmannia marginataVitrina pellucidaDoes the Vitrina pellucida eat mushrooms? I do not know. But what does it eat?

British malacologist John William Taylor (1845-1931) wrote in 1914: “Vitrina pellucida has an almost omnivorous appetite, and is credited with feeding upon Liverwort (Jungermannia platyphylla), mosses, fallen leaves, and decaying vegetable matter. It is also carnivorous, being said by Dr. Baudon to voraciously devour raw mutton, and will also feast upon the bodies of dead or dying worms and animals of its own or other species.”

Falkner et al. wrote in their dataset in 2001:
Deciduous forest litter 2
Lichens (gen.) 1
Epilithic/epiphytic 1
Living algae 1
Higher plants (gen.) 2
Dead 2
Carnivorous/saprophagous 2

This can be read (approximately) in human language: Vitrina pellucida eat sometimes deciduous forest litter and dead plants. It is sometimes carnivorous and/or saprophagous. Rarely it also feeds on epilithic and/or epiphytic lichens and on living algae.

Both authors does not mention fungi. Falkner at al. ignored information, that it eats mosses (although mosses have its own column in the dataset and although they cited Taylor in the reference section), but they listed lichens. Among hundreds of references listed at the end on the book only, it impossible to practically detect where informations comes from.

References

Falkner G., Obrdlík P., Castella E. & Speight M. C. D. 2001: Shelled Gastropoda of Western Europe. München: Friedrich-Held-Gesellschaft, 267 pp.

Horsák M., Juřičková L. & Picka J. 2013: Měkkýši České a Slovenské republiky. Molluscs of the Czech and Slovak Republics. Kabourek, Zlín, 264 pp. (in Czech and English). page 112 and page 34.

Taylor J. W. 1914″ Monograph of the land and freshwater Mollusca of the British Isles. Zonitidae, Endodontidae, Helicidae. Leeds, page 7.

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Photo of the day (27): three gastropods from the family Vitrinidae

These are three gastropods from the family Vitrinidae on a human hand. Each of them belong to a different genus. All of them shows a different level of a reduction of its shell.

Vitrina pellucidae and Eucobresia diaphana and Semilimax semilimaxThe upper one is Vitrina pellucida. This gastropod can completely withdraw into its shell and therefore it is called a snail.

Two others can not fully withdraw into their shells. They are semi-slugs.

The lower left is Eucobresia diaphana. Mantle covers apical part of the shell.

The lower right is Semilimax semilimax. Quite big mantle lobe is covering an apex. The reduction of the shell of Semilimax semilimax is the highest among these three species.

Genera in the family Vitrinidae shows the complete example of the shell reduction from the snails through semi-slugs to slugs.

Examples of snails: Phenacolimax, Vitrina.

Examples of semi-slugs: Eucobresia, Semilimax, Vitrinobrachium.

Example of a slug in Vitrinidae is Plutonia atlantica. It is a slug with an internal shell living on Azores.

References:

Species summary for Plutonia atlantica. AnimalBase, accessed 2 January 2014.

Species summary for Vitrina pellucida. AnimalBase, accessed 2 January 2014.