Freitag, 24. Mai 2013

Species of the Day (May 25th, 2013) - Cepaea hortensis O. F. MÜLLER, 1974

This time, I want to present you another animal. This animal is Cepaea hortensis O.F. MUELLER; a snail from the Helicidae family, which belongs to the order of the Pulmonata. The Pulmonata are one of the classic orders of snails (Gastropoda). It includes all snails with “lungs” instead of gills. The Taxonomy is

  • Mollusca (“Molluscs”)
  •   -> Gastropoda (“Snails”)
  •     -> Pulmonata (“Terrestrial Snails with lungs”)
  •      -> Helicidae
  •       -> Cepaea ("banded snails")
  •         -> Cepaea hortensis

*) please note: this is the old taxonomy, but you still find this in many books.

In English, the species is known as “white-lipped banded snail” and in German as “Garten-Bänderschnecke”.

1) Description

C. hortensis - habitus

C. hortensis is a small snail, which can reach a maximum length of 12 centimeters. Its body has a white or silver-white color with a dark stripe on the back. As all snails, the species has four antennas (two short and two long). The eyes are located at the end of the long antennas.

C. hortensis - head with antennas and eyes

The shell has a white aperture (“Mündung”), what is an distinctive feature of this species and the reason for its name. In some rare cases, the aperture may be brown, but this is a mutation

C. hortensis with white aperture (right side)

As with the most snails from the Helicidae, the shell of C. hortensis is spherical. It also has a high variation in color. In the most cases, the shell is dull yellow with brown stripes but shells without stripes are also very common (as on my picture). Some snails even have a brown shell.

C. hortensis - shell (side view)

The measurements of the shell are 16 millimeters in height and 22 millimeters in diameter. It has between 5 and 5.5 convolutions.

C. hortensis is a hermaphrodite; so it has a male and a female reproductive system. If a snail meets a sexual partner, one animal works in its love dart (Gypsobelum) to inseminate the partner. The Gypsobelum of C. hortensis has several glands, what is another distinctive feature of this species.

C. hortensis - view into the aperture
Self-fertilization is also possible, but not very common

C. hortensis is closely related to Cepaea nemoralis (brown-lipped snail). As the name suggest, the aperture of C. nemoralis is brown, what is a good differential between these two species (as long as you haven't the variation with a brown aperture).

2) Distribution & Biology

The white-lipped banded snail is native to Europe and can also be found in North America as neophyte. It colonized a wide range of different habitats like grassland, woods, gardens, parks and so on.

C. hortensis - shell (aperture is black by dirt)

C. hortensis lives in dense vegetation. The most time of the day, the snail rest in its shell. When active, the species searches for food. It eats plants like hogweed, ragwort or nettles. However, the species isn't a vermin and no hazard for gardens or ornamental plants.

C. hortensis - variant without black stripes

The natural enemies of C. hortensis includes all predators, which are able to break the shell. A special predator is the Song Thrush (Trudus philomelos; “Singdrossel” in German). This birds cracks the shell by throwing it on rocks and stones. Around such stones, you can find the remains of shells of C. hortensis

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