Peristoma

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Peristoma
Peristoma merduenianum

Peristoma merduenianum

Systematics
Subordination : Land snails (Stylommatophora)
Superfamily : Enoidea
Family : Wolverine snails (Enidae)
Subfamily : Eninae
Tribe : Chondrulini
Genre : Peristoma
Scientific name
Peristoma
Krynicki , 1833

Peristoma is a genus of the family of wolverines (Enidae) from the suborder of land snails (Stylommatophora).

features

The right-hand winding, oblong-conical to tower-shaped cases are 12 to 20 mm high and 4 to 9 mm wide. They have 6.5 to 9 turns with only a moderately convex periphery. The mouth is pointed ovoid, the mouth plane is oblique to the coil axis. The edge of the mouth is only slightly bent with thin mouth edges. The points of attachment of the mouth to the previous turn approach each other somewhat. They are connected to one another by a more or less thick whitish layer. The mouth is without teeth. The surface of the whitish-yellowish to maroon-brown housing shows indistinct radial stripes and wrinkles and sometimes fine spiral elements.

In the male tract of the hermaphroditic genital apparatus, the spermatic duct , which is not very twisted, enters the comparatively short epiphallus . A short, conical flagellum is formed at the point of entry, which is opposite to a shorter, conical epiphallus caecum. The epiphallus is longer than the penis. At the transition from the epiphallus to the penis, the penis is very strong and flattened-spherically thickened, more than three times the thickness of the epiphallus. The thickness gradually decreases to the thickness of the epiphallus at the confluence of the penis with the atrium. A penile caecum is missing, the penile appendix opens directly into the atrium. It consists of a thickened lower part ((A-1, significantly longer than the penis), followed by a short, spherical part (A-2). The thinner part (A-3) is comparatively short, while the thin upper part Part (A-4) is very long. The club-shaped end part (A-5) is moderately long. Overall, the penile appendix has about twice the length of penis and epiphallus together. The stimulator inside the penis is cone-shaped with a longitudinal groove. The retractor muscle splits into two cords, one cord attaches to the penis, near the transition to the epiphallus, the other cord near the end of the thickened part (A-1) of the penile appendix. In the female tract the free fallopian tube (oviduct) is only slightly longer than The vagina, the spermathec is comparatively short, the stalk thick and not twisted, the bladder lies roughly in the middle of the prostate, and a short worm-shaped diverticulum branches off just in front of the bladder .

Geographical distribution

The few species of the genus occur in the Crimea and the western Caucasus .

Taxonomy

The genus was proposed by Josef Krynicki in 1833. The only species assigned at that time and thus the type species is Peristoma merdueniana , recte Peristoma merduenianum , since Peristoma is a neuter gender. The genre is recognized as an independent genre in the more recent publications.

supporting documents

literature

  • Burçin Aşkım Gümüş, Eike Neubert: New taxa of terrestrial molluscs from Turkey (Gastropoda, Pristilomatidae, Enidae, Hygromiidae, Helicidae). ZooKeys, 171: 17-37, 2012 doi : 10.3897 / zookeys.171.2273
  • Anatolij A. Schileyko: Treatise on Recent Terrestrial Pulmonate Molluscs. Part 2. Gastrocoptidae, Hypselostomatidae, Vertiginidae, Truncatellinidae, Pachnodidae, Enidae, Sagdidae. Ruthenica, Supplement 2 (2): 129-261, Moscow 1998 ISSN  0136-0027
  • Francisco W. Welter-Schultes: European non-marine molluscs, a guide for species identification = identification book for European land and freshwater mollusks. A1-A3 p., 679 p., Q1-Q78 p., Planet Poster Ed., Göttingen 2012, ISBN 3-933922-75-5 , ISBN 978-3-933922-75-5 (p. 132)

Individual evidence

  1. ^ Johann Krynicki: Novae species aut minus cognitae e chondri, bulimi, peristomae helicisque generibus praecipue Rossiæ meridionalis. Bulletin de la Société Impériale des Naturalistes de Moscou, 6: 391-436, Moscow 1833 Online at biodiversitylibrary.org .

On-line

Web links