Mesolimax

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Mesolimax
Systematics
Superordinate : Heterobranchia
Order : Lung snails (pulmonata)
Subordination : Land snails (Stylommatophora)
Family : Field slugs (Agriolimacidae)
Subfamily : Mesolimacinae
Genre : Mesolimax
Scientific name of the  subfamily
Mesolimacinae
Hausdorf , 1998
Scientific name of the  genus
Mesolimax
Pollonera , 1888

Mesolimax is a genus of the nudibranch family of the field slugs (Agriolimacidae) from the suborder of the land snails (Stylommatophora). It currently only includes two types. Mesolimax is the only genus of the monotypic subfamily Mesolimacinae .

features

The representatives of the genus Mesolimax have a slender body of medium size. The length indications differ between the authors: up to about 6 cm according to Schileyko, up to 7 cm according to Fechter and Falkner (for the middle beak ( Mesolimax brauni )) or "up to 53 mm" according to Wiktor. The coat takes up less than 3/4 of the body length. The breathing hole (pseumostom) lies slightly behind the middle of the mantle shield and is surrounded by a clear, raised ring. The keel at the rear end of the body is weak and relatively short. The skin is thick and covered with strong wrinkles. The animals are colored olive brown, red brown, dark brown to black. The sole of the foot is divided into three parts in the longitudinal direction. The two side panels of the sole each have two (or more) longitudinal furrows and numerous transverse furrows. The midfield shows V-shaped transverse furrows curved backwards.

The peel leaflet in the mantle is almost symmetrical (in the longitudinal axis). The nucleus lies at the rear edge of the plate.

In the genital tract the spermatic duct (vas deferens) runs parallel to the penis; The penis and vas deferens are surrounded by a thin membrane. The penis is very long, cylindrical and somewhat twisted. The penile retractor muscle attaches subapically to the penis. The free fallopian tube (oviduct) is moderately long and thin, the vagina is short. The stem of the sperm library is very short. In the digestive tract, the rectum runs through the posterior attachment point of the main retractor muscle.

According to Hausdorf, apomorphic features of the genus and subfamily are the membrane that surrounds the penis and vas deferens, the diagonal, V-shaped pits in the side panels of the sole of the foot and the course of the intestine through the posterior attachment point of the main retractor muscle.

Geographical distribution, habitat and way of life

The species occurs in western and southwestern Asia Minor as well as on the offshore Greek islands (e.g. Rhodes). Earlier statements that the distribution area also extends into the Caucasus and the Balkans were rejected as incorrect by Wiktor (2001).

The animals live very hidden under stones and dense vegetation. Usually only juvenile specimens are found. This phenomenon is explained by the fact that either the mortality during the juvenile phase is very high and very few specimens become adults, or that the adults live so hidden that they are simply found less often.

Taxonomy and systematics

The genus Mesolimax was established by Carlo Pollonera in 1888 . Type species by monotype is Mesolimax brauni Pollonera, 1888 (the mean snail). Currently only two species are included in the genus. The genus was previously mostly placed in the family of the Schnegel (Limacidae). In 1998 Bernhard Hausdorf presented a cladistic analysis of Limacoidea s. l. in front. According to his results, the genus Mesolimax is the sister group of the Agriolimacinae. Therefore, he established the monotypical subfamily Mesolimacinae for the genus Mesolimax . The subfamily assignment of the genus Mesolimax and the subfamily division of the Agriolimacidae into Mesolimacinae and Agriolimacinae is accepted by Philippe Bouchet & Jean-Pierre Rocroi as well as the Fauna Europaea.

  • Family field snails (Agriolimacidae Wagner, 1935)
    • Subfamily Mesolimacinae Hausdorf, 1998
      • Genus Mesolimax Pollonera, 1888 (Schileyko put the genus with question marks about the subfamily Limacinae, family Schnegel (Limacidae))

supporting documents

literature

  • Bernhard Hausdorf: Phylogeny of the Limacoidea sensu lato (Gastropoda: Stylommatophora). In: Journal of Molluscan Studies. 64: 35-66, London 1998 ISSN  0260-1230
  • Anatolij A. Schileyko: Treatise on Recent Terrestrial Pulmonate Molluscs Part 11 Trigonochlamydidae, Papillodermidae, Vitrinidae, Limacidae, Bielziidae, Agriolimacidae, Boettgerillidae, Camaenidae. Ruthenica, Supplement 2 (11): 1467-1626, Moscow 2003 ISSN  0136-0027
  • Andrzej Wiktor: Fauna Graeciae. VIII. The slugs of Greece (Arionidae, Milacidae, Limacidae, Agriolimacidae - Gastropoda, Stylommatophora). 240 pp., Natural History Museum of Crete & Hellenic Zoologic Society, Iraklio, Crete, 2001 ISBN 960-367-005-7

Individual evidence

  1. ↑ a b Schileyko (2003: p. 1497/8)
  2. ^ Fechter, Rosina & Gerhard Falkner: Mollusks. 287 p., Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10) ISBN 3-570-03414-3 (p. 190, Mittelschnegel)
  3. ↑ a b c Wiktor (2001: p. 180/1)
  4. ↑ a b Hausdorf (1998: p. 64)
  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
  6. ^ Philippe Bouchet and Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005 ISSN  0076-2997 (p. 269, subfamily Mesolimacinae)
  7. ↑ Fauna Europaea - Mesolimacinae

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