Dark forest snail
| Dark forest snail | ||||||||||||
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Cochlostoma obscurum |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Cochlostoma obscurum | ||||||||||||
| ( Draparnaud , 1805) |
The dark forest cap snail ( Cochlostoma obscurum ) is a species of snail from the family of the forest cap snail (Cochlostomatidae) in the order Architaenioglossa ("old bandworm") that lives on land .
features
The right-handed, comparatively large case is 10.0 to 11.5 mm high and 4.8 mm wide. It has 7 to 8½ whorls that are only slightly rounded. The first steps form a slight shoulder, but this is completely hidden by the seam. The outer line is almost straight. The last deal can be an easy shoulder near the outer edge. The surface is slightly wrinkled on the first half embryonic turn. Very fine ribs form on the next 1.5 turns. The following turns are provided with strong, somewhat irregularly arranged ribs; about 8 to 9 ribs come to a millimeter. On the last turns, the ribs become denser (12 to 13 ribs per millimeter). The end turn rises little or not at all towards the mouth. In the frontal view, the mouth has a pear-shaped outline. The mouth edge is bent back and reinforced. It is white in color and uniform, i.e. not thickened on the inside. The bent edge of the mouth becomes narrower towards the spindle, but is not drawn out in the shape of an ear. The navel is very tight. The tan case shows three rows of dark spots or bands: a row of brown spots below the seam, an interrupted brown band above the seam, and a wide periumbilical brown band interrupted by white intervals.
The soft body is red on top, whitish with reddish tones on the sides and pale on the underside.
Similar species
As in the case of the small forest snail ( Cochlostom septemspirale ), the mouth edge is bent back, reinforced and also colored white, but does not consist of two parts as in this species.
Geographical distribution and habitat
The distribution area includes two non-contiguous areas in France and northern Spain (Départements Yonne and Côte-d'Or in Burgundy ) and in the northern foothills of the Pyrenees . The somewhat larger populations of the high mountain Pyrenees were regarded by Gofas (2001) as a separate species, Cochlostoma crassilabrum . Other authors, on the other hand, see Cochlostoma crassilabrum as a synonym for Cochlostoma obscurum . Correspondingly, in the second case, the distribution area extends to the Spanish side of the high mountain Pyrenees.
The animals live on and under limestone rocks and limestone rubble in the leaf litter of forests.
Way of life
The animals are not particularly active and move very slowly. The case is carried upwards at a slight angle. The females lay very large, almost cylindrical eggs up to 1.5 mm in length. The young hatch after 20 to 25 days.
Taxonomy
The taxon was first described in 1805 by Jacques Philippe Raymond Draparnaud as Cyclostoma obscurum . Wilhelm Kobelt first placed the species in the genus Cochlostoma Jan, 1830. Today, the species is usually placed in the subgenus Cochlostoma (Obscurella) Clessin, 1889. Raven (1990) treated Obscurella as a separate genus.
The taxon is not treated uniformly in the literature. Gofas (2001) sees the somewhat larger populations of the high mountain Pyrenees as a separate species, Cochlostoma crassilabrum . In contrast, other authors consider Cochlostoma crassilabrum to be a synonym for Cochlostoma obscurum . Depending on the view, the distribution area is limited to France or in the second case extends into Spain, and the variability in size is significantly smaller in the first case (10 to 11.5 mm high) compared to 10 to 14 mm in the second Conception. Gofas (2001) performed an allozyme electrophoresis on the species. He found a calculated genetic distance of 0.18 to 0.21 between the populations in Burgundy and the foothills of the Pyrenees. In contrast, the genetic distance between the foothill Pyrenees population and the high mountain Pyrenees population was significantly greater at 0.32 to 0.42 and approached the genetic distance of 0.45 to 0.67 for the sympatric species Cochlostoma partioti and Cochlostoma crassilabrum .
supporting documents
literature
- Serge Gofas 2001: The systematics of Pyrenean and Cantabrian Cochlostoma (Gastropoda, Cyclophoroidea) revisited. Journal of Natural History, 35 (9): 1277-1369 doi : 10.1080 / 002229301750384301
- Michael P. Kerney, RAD Cameron & Jürgen H. Jungbluth: The land snails of Northern and Central Europe. 384 pp., Paul Parey, Hamburg & Berlin 1983 ISBN 3-490-17918-8 (p. 64)
- Francisco W. Welter-Schultes: European non-marine molluscs, a guide for species identification = identification book for European land and freshwater mollusks. A1-A3 S., 679 S., Q1-Q78 S., Göttingen, Planet Poster Ed., 2012 ISBN 3-933922-75-5 , ISBN 978-3-933922-75-5
Individual evidence
- ^ Jacques Philippe Raymond Draparnaud: Histoire naturelle des mollusques terrestres et fluviatiles de la France. Ouvrage posthumous. Pp. I-VIII, pp. 1-134, plates 1-13, Paris, Montpellier, Plassan, Renaud. Online at www.biodiversitylibrary.org: pp.39-40 or plate 1, Fig. 13
- ↑ Fauna Europaea - Cochlostoma (Obscurella) obscurum (Draparnaud, 1805)
- ↑ JGM (Han) Raven: A revision of Obscurella Clessin, 1889 (Gastropoda, Prosobranchia, Cyclophoridae). Basteria, 54: pp. 1-62, Leiden 1990.
On-line
Web links
- Molluscs of Central Europe
- Cochlostoma obscurum inthe IUCN Red List of Threatened Species 2013.2. Posted by: Feher, Z., 2011. Retrieved February 14, 2014.