Middle cone

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Middle cone
Systematics
Class : Snails (gastropoda)
Order : Lung snails (pulmonata)
Subordination : Land snails (Stylommatophora)
Family : Field slugs (Agriolimacidae)
Genre : Mesolimax
Type : Middle cone
Scientific name
Mesolimax brauni
Pollonera , 1888

The middle snail ( Mesolimax brauni ) is a species of slug from the family of the field slugs ( Agriolimacidae), which belongs to the suborder of the land snails (Stylommatophora).

features

The body is comparatively slim and reaches a medium length. The maximum length specifications differ from author to author: up to 53 mm (average 35 to 40 mm) according to Wiktor (2001), up to 55 mm according to AnimalBase, up to 59.7 mm according to Yildirim and Kebapçi (2004) and up to 7 cm according to Fechter and Falconer (1990). The color varies from olive brown to reddish brown to dark brown. Melanistic specimens are also rare . The coat takes up less than 3/4 of the total body length and is darker than the body. The breathing hole is in the middle to slightly behind the middle of the mantle shield. The short keel is usually a little lighter in color. The cream-colored sole of the foot has three longitudinal fields, the middle field is often somewhat darker and shows V-shaped transverse furrows directed backwards. There are two longitudinal furrows in the side panels.

The shell plate is quite stable, roughly rectangular and has rounded corners and growth lines. The nucleus is approximately central and symmetrical. In the radula , the central and posterior teeth have poorly developed secondary tips, whereas the marginal teeth are dagger-like. Only two intestinal loops are formed. The rectum has no caecum , or at most as a small lateral swelling. The intestine runs through the posterior attachment point of the main retractor muscle.

In the genital apparatus, the tubular penis is about half the length of the body and is not or only slightly twisted. The spermatic duct ( vas deferens ) and penile retractor are applied apically to the penis. The basal part of the penis and part of the spermatic duct are surrounded by a thin membrane. The ommatophore muscle and the penis cross each other. The spermathec is oval and relatively small, the stem of the spermathec is shorter than the spermathec itself. The fallopian tube is tubular, the atrium is short.

Similar species

The middle cone differs from the other species of the genus Mesolimax , M. escherichi Simroth, 1899, by the mostly lighter colors ( M. escherichi is always black), by the slightly longer penis, which reaches about half the body length (compared to the shorter penis at M. escherichi , which reaches only ⅓ of the body length) and through the side panels of the three-part sole of the foot, which have two longitudinal furrows (compared to three or more longitudinal furrows in M. escherichi ).

Geographical distribution, habitat and way of life

The species occurs on the Aegean islands of Rhodes , Lesbos and Karpathos as well as in southwestern Turkey, especially between Izmir and Silifke .

The animals live very hidden in crevices, under stones, under leaves and in dense vegetation. Strangely enough, mostly only juvenile specimens are found throughout the year . Wiktor explains this observation with the fact that either the mortality during the juvenile phase is very high and only very few specimens become adults, or that the adults change their habitat and / or live so hidden that they are simply found much less often. Little is known about the way of life of the species; at least juvenile specimens seem to have a tendency towards synanthropy .

Taxonomy

The species was first described by Carlo Pollonera in 1888. It is the type species of the genus Mesolimax Pollonera, 1888.

supporting documents

literature

  • Hesse, Paul 1926: The nudibranchs of the Palaearctic region. Treatises of the Archiv für Molluskenkunde, 2 (1): 1–152, Frankfurt / Main.
  • Fechter, Rosina & Gerhard Falkner: Mollusks. 287 pp., Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10) ISBN 3-570-03414-3
  • Wiktor, Andrzej 1971: The nudibranchs (Milacidae and Limacidae, Pulmonata) collected by the Dutch biological expedition to Turkey in 1959 with a description of a new Deroceras species from the Balkans and Turkey, Zoologische Mededelingen, 45 (23): 261 –280, Leiden PDF .
  • Wiktor, Andrzej 2001: Fauna Graeciae. VIII. The slugs of Greece (Arionidae, Milacidae, Limacidae, Agriolimacidae - Gastropoda, Stylommatophora). 240 p., Natural History Museum of Crete & Hellenic Zoologic Society, Heraklion, Crete
  • M. Zeki Yildirim & Ümit Kebapçi: Slugs (Gastropoda: Pulmonata) of the Lakes Region (Göller Bölgesi) in Turkey. Turkish Journal of Zoology, 28: 155-160, Ankara 2004 PDF .

On-line

Individual evidence

  1. ↑ a b c Wiktor (2001: p. 181/2)
  2. ↑ AnimalBase - Mesolimax brauni
  3. ↑ a b Yildirim & Kebapçi (2004: p. 159)
  4. ^ Fechter & Falkner (1990: p. 190)
  5. ^ Pollonera, Carlo 1888: Appunti di malacologia. Bollettino dei Musei di Zoologia ed Anatomia Comparata della Reale Università di Torino, 3 (43): 1-10, Turin Online at Biodiversity Heritage Library (p. 8).

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